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Background: Synaptic degeneration is a central pathogenic event in Alzheimer's disease that occurs early during the course of disease and correlates with cognitive symptoms. The pre-synaptic vesicle protein synaptotagmin-1 appears to be essential for the maintenance of an intact synaptic transmission and cognitive function. Synaptotagmin-1 in cerebrospinal fluid is a candidate Alzheimer biomarker for synaptic dysfunction that also may correlate with cognitive decline. Methods: In this study, a novel mass spectrometry-based assay for measurement of cerebrospinal fluid synaptotagmin-1 was developed, and was evaluated in two independent sample sets of patients and controls. Sample set I included cerebrospinal fluid samples from patients with dementia due to Alzheimer's disease (N = 17, age 52-86 years), patients with mild cognitive impairment due to Alzheimer's disease (N = 5, age 62-88 years), and controls (N = 17, age 41-82 years). Sample set II included cerebrospinal fluid samples from patients with dementia due to Alzheimer's disease (N = 24, age 52-84 years), patients with mild cognitive impairment due to Alzheimer's disease (N = 18, age 58-83 years), and controls (N = 36, age 43-80 years). Results: The reproducibility of the novel method showed coefficients of variation of the measured synaptotagmin-1 peptide 215-223 (VPYSELGGK) and peptide 238-245 (HDIIGEFK) of 14 % or below. In both investigated sample sets, the CSF levels of synaptotagmin-1 were significantly increased in patients with dementia due to Alzheimer's disease (P = 0.0001) and in patients with mild cognitive impairment due to Alzheimer's disease (P < 0.001). In addition, in sample set I the synaptotagmin-1 level was significantly higher in patients with mild cognitive impairment due to Alzheimer's disease compared with patients with dementia due to Alzheimer's disease (P ≤ 0.05). Conclusions: Cerebrospinal fluid synaptotagmin-1 is a promising biomarker to monitor synaptic dysfunction and degeneration in Alzheimer's disease that may be useful for clinical diagnosis, to monitor effect on synaptic integrity by novel drug candidates, and to explore pathophysiology directly in patients with Alzheimer's disease. [ABSTRACT FROM AUTHOR]

Background: Lrrk2, a gene linked to Parkinson's disease, encodes a large scaffolding protein with kinase and GTPase activities implicated in vesicle and cytoskeletal-related processes. At the presynaptic site, LRRK2 associates with synaptic vesicles through interaction with a panel of presynaptic proteins., Results: Here, we show that LRRK2 kinase activity influences the dynamics of synaptic vesicle fusion. We therefore investigated whether LRRK2 phosphorylates component(s) of the exo/endocytosis machinery. We have previously observed that LRRK2 interacts with NSF, a hexameric AAA+ ATPase that couples ATP hydrolysis to the disassembling of SNARE proteins allowing them to enter another fusion cycle during synaptic exocytosis. Here, we demonstrate that NSF is a substrate of LRRK2 kinase activity. LRRK2 phosphorylates full-length NSF at threonine 645 in the ATP binding pocket of D2 domain. Functionally, NSF phosphorylated by LRRK2 displays enhanced ATPase activity and increased rate of SNARE complex disassembling. Substitution of threonine 645 with alanine abrogates LRRK2-mediated increased ATPase activity., Conclusions: Given that the most common Parkinson's disease LRRK2 G2019S mutation displays increased kinase activity, our results suggest that mutant LRRK2 may impair synaptic vesicle dynamics via aberrant phosphorylation of NSF.

Recessive loss-of-function mutations in the mitochondrial enzyme Glutamate Pyruvate Transaminase 2 (GPT2) cause intellectual disability in children. Given this cognitive disorder, and because glutamate metabolism is tightly regulated to sustain excitatory neurotransmission, here we investigate the role of GPT2 in synaptic function. GPT2 catalyzes a reversible reaction interconverting glutamate and pyruvate with alanine and alpha-ketoglutarate, a TCA cycle intermediate; thereby, GPT2 may play an important role in linking mitochondrial tricarboxylic acid (TCA) cycle with synaptic transmission. In mouse brain, we find that GPT2 is enriched in mitochondria of synaptosomes (isolated synaptic terminals). Loss of Gpt2 in mouse appears to lead to reprogramming of glutamate and glutamine metabolism, and to decreased glutamatergic synaptic transmission. Whole-cell patch-clamp recordings in pyramidal neurons of CA1 hippocampal slices from Gpt2-null mice reveal decreased excitatory post-synaptic currents (mEPSCs) without changes in mEPSC frequency, or importantly, changes in inhibitory post-synaptic currents (mIPSCs). Additional evidence of defective glutamate release included reduced levels of glutamate released from Gpt2-null synaptosomes measured biochemically. Glutamate release from synaptosomes was rescued to wild-type levels by alpha-ketoglutarate supplementation. Additionally, we observed evidence of altered metabolism in isolated Gpt2-null synaptosomes: decreased TCA cycle intermediates, and increased glutamate dehydrogenase activity. Notably, alterations in the TCA cycle and the glutamine pool were alleviated by alpha-ketoglutarate supplementation. In conclusion, our data support a model whereby GPT2 mitochondrial activity may contribute to glutamate availability in pre-synaptic terminals, thereby highlighting potential interactions between pre-synaptic mitochondrial metabolism and synaptic transmission. [ABSTRACT FROM AUTHOR]

Background: Reversible cerebral vasoconstriction syndrome (RCVS) is characterized by severe headaches, often thunderclap headaches, and a multifocal constriction of the cerebral arteries. Although RCVS can occur spontaneously, some cases occur after exposure to drugs. We describe the first case of RCVS in which methylphenidate, a drug with vasoconstrictive properties, is the only suspected drug. Still an unexpected adverse drug reaction of methylphenidate, and so far observed with the concomitant use of vasoactive drugs and methylphenidate, RCVS can be observed when methylphenidate is used alone. Case presentation: A 44-year-old French female presented with sudden onset of severe thunderclap headache during exercise. She had been treated for about 2 years with 54 mg extended-release MPH twice a week for attention deficit / hyperactivity disorder. After clinical, biological and imaging examinations, clinicians concluded to a highly probable RCVS diagnosis, probably linked to methylphenidate use. Major causes of RCVS were ruled out and the methylphenidate treatment was discontinued. The outcome was favourable with nimodipine treatment. We also describe two other cases of methylphenidate induced RCVS recorded in French Pharmacovigilance Database. Moreover, RCVS is an adverse reaction reported more frequently than expected with methylphenidate in the International Pharmacovigilance Database (VigiBase®), suggesting a pharmacovigilance signal. Given its pharmacodynamics, i.e. pre-synaptic dopamine and norepinephrine reuptake inhibition, methylphenidate is theoretically likely to contribute to this vascular event. Conclusions: The role of methylphenidate needs to be considered in case of RCVS diagnosis observed in a treated patient. Although the frequency of this potential adverse drug reaction is expected to be rare, clinicians should be aware of its possible occurrence, given the ever-increasing use of methylphenidate. [ABSTRACT FROM AUTHOR]

Background: The snake genera Atropoides, Cerrophidion, and Metlapilcoatlus form a clade of neotropical pit vipers distributed across Mexico and Central America. This study evaluated the myotoxic and neurotoxic effects of nine species of Atropoides, Cerrophidion, and Metlapilcoatlus, and the neutralising efficacy of the ICP antivenom from Costa Rica against these effects, in the chick biventer cervicis nerve-muscle preparation. Given the prominence of PLA2s within the venom proteomes of these species, we also aimed to determine the neutralising potency of the PLA2 inhibitor, varespladib. Results: All venoms showed myotoxic and potential neurotoxic effects, with differential intra-genera and inter-genera potency. This variation was also seen in the antivenom ability to neutralise the muscle damaging pathophysiological effects observed. Variation was also seen in the relative response to the PLA2 inhibitor varespladib. While the myotoxic effects of M. mexicanus and M. nummifer venoms were effectively neutralised by varespladib, indicating myotoxicity is PLA2 mediated, those of C. godmani and M. olmec venoms were not, revealing that the myotoxicity is driven by non-PLA2 toxin types. Conclusions: This study characterises the myotoxic and neurotoxic venom activity, as well as neutralisation of venom effects from the Atropoides, Cerrophidion, and Metlapilcoatlus clade of American crotalids. Our findings contribute significant clinical and evolutionary knowledge to a clade of poorly researched snakes. In addition, these results provide a platform for future research into the reciprocal interaction between ecological niche specialisation and venom evolution, as well as highlighting the need to test purified toxins to accurately evaluate the potential effects observed in these venoms. [ABSTRACT FROM AUTHOR]

Human studies consistently identify bioenergetic maladaptations in brains upon aging and neurodegenerative disorders of aging (NDAs), such as Alzheimer's disease, Parkinson's disease, Huntington's disease, and Amyotrophic lateral sclerosis. Glucose is the major brain fuel and glucose hypometabolism has been observed in brain regions vulnerable to aging and NDAs. Many neurodegenerative susceptible regions are in the topological central hub of the brain connectome, linked by densely interconnected long-range axons. Axons, key components of the connectome, have high metabolic needs to support neurotransmission and other essential activities. Long-range axons are particularly vulnerable to injury, neurotoxin exposure, protein stress, lysosomal dysfunction, etc. Axonopathy is often an early sign of neurodegeneration. Recent studies ascribe axonal maintenance failures to local bioenergetic dysregulation. With this review, we aim to stimulate research in exploring metabolically oriented neuroprotection strategies to enhance or normalize bioenergetics in NDA models. Here we start by summarizing evidence from human patients and animal models to reveal the correlation between glucose hypometabolism and connectomic disintegration upon aging/NDAs. To encourage mechanistic investigations on how axonal bioenergetic dysregulation occurs during aging/NDAs, we first review the current literature on axonal bioenergetics in distinct axonal subdomains: axon initial segments, myelinated axonal segments, and axonal arbors harboring pre-synaptic boutons. In each subdomain, we focus on the organization, activity-dependent regulation of the bioenergetic system, and external glial support. Second, we review the mechanisms regulating axonal nicotinamide adenine dinucleotide (NAD+) homeostasis, an essential molecule for energy metabolism processes, including NAD+ biosynthetic, recycling, and consuming pathways. Third, we highlight the innate metabolic vulnerability of the brain connectome and discuss its perturbation during aging and NDAs. As axonal bioenergetic deficits are developing into NDAs, especially in asymptomatic phase, they are likely exaggerated further by impaired NAD+ homeostasis, the high energetic cost of neural network hyperactivity, and glial pathology. Future research in interrogating the causal relationship between metabolic vulnerability, axonopathy, amyloid/tau pathology, and cognitive decline will provide fundamental knowledge for developing therapeutic interventions. [ABSTRACT FROM AUTHOR]

Alpha-synuclein (aSyn) is a pre-synaptic monomeric protein that can form aggregates in neurons in Parkinson's disease (PD), Parkinson's disease with dementia (PDD) and dementia with Lewy bodies (DLB), and in oligodendrocytes in multiple system atrophy (MSA). Although aSyn in astrocytes has previously been described in PD, PDD and DLB, the biochemical properties and topographical distribution of astrocytic aSyn have not been studied in detail. Here, we present a systematic investigation of aSyn astrocytic pathology using an expanded antibody toolset covering the entire sequence and key post-translational modifications (PTMs) of aSyn in Lewy body disorders (LBDs) and in MSA. Astrocytic aSyn was detected in the limbic cortical regions of LBDs but were absent in main pathological regions of MSA. The astrocytic aSyn was revealed only with antibodies against the mid N-terminal and non-amyloid component (NAC) regions covering aSyn residues 34–99. The astroglial accumulations were negative to canonical aSyn aggregation markers, including p62, ubiquitin and aSyn pS129, but positive for phosphorylated and nitrated forms of aSyn at Tyrosine 39 (Y39), and not resistant to proteinase K. Our findings suggest that astrocytic aSyn accumulations represent a major part of aSyn pathology in LBDs and possess a distinct sequence and PTM signature that is characterized by both N- and C-terminal truncations and modifications at Y39. This is the first description that aSyn accumulations are made solely from N- and C-terminally cleaved aSyn species and the first report demonstrating that astrocytic aSyn is a mixture of Y39 phosphorylated and nitrated species. These observations underscore the importance of systematic characterization of aSyn accumulations in different cell types to capture the aSyn pathological diversity in the brain. Our findings combined with further studies on the role of astrocytic pathology in the progression of LBDs can pave the way towards identifying novel disease mechanisms and therapeutic targets. [ABSTRACT FROM AUTHOR]

Multiple studies have recognized the involvement of the complement cascade during Alzheimer's disease pathogenesis. However, the specific role of C5a-C5aR1 signaling in the progression of this neurodegenerative disease is still not clear. Furthermore, its potential as a therapeutic target to treat AD still remains to be elucidated. Canonically, generation of the anaphylatoxin C5a as the result of complement activation and interaction with its receptor C5aR1 triggers a potent inflammatory response. Previously, genetic ablation of C5aR1 in a mouse model of Alzheimer's disease exerted a protective effect by preventing cognitive deficits. Here, using PMX205, a potent, specific C5aR1 antagonist, in the Tg2576 mouse model of Alzheimer's disease we show a striking reduction in dystrophic neurites in parallel with the reduced amyloid load, rescue of the excessive pre-synaptic loss associated with AD cognitive impairment and the polarization of microglial gene expression towards a DAM-like phenotype that are consistent with the neuroprotective effects seen. These data support the beneficial effect of a pharmacological inhibition of C5aR1 as a promising therapeutic approach to treat Alzheimer's disease. Supportive of the safety of this treatment is the recent FDA-approval of another other C5a receptor 1 antagonist, Avacopan, as a treatment for autoimmune inflammatory diseases. [ABSTRACT FROM AUTHOR]

Dementia with Lewy bodies (DLB) is pathologically defined by the cytoplasmic accumulation of alpha-synuclein (aSyn) within neurons in the brain. Predominately pre-synaptic, aSyn has been reported in various subcellular compartments in experimental models. Indeed, nuclear alpha-synuclein (aSynNuc) is evident in many models, the dysregulation of which is associated with altered DNA integrity, transcription and nuclear homeostasis. However, the presence of aSynNuc in human brain cells remains controversial, yet the determination of human brain aSynNuc and its pathological modification is essential for understanding synucleinopathies. Here, using a multi-disciplinary approach employing immunohistochemistry, immunoblot, and mass-spectrometry (MS), we confirm aSynNuc in post-mortem brain tissue obtained from DLB and control cases. Highly dependent on antigen retrieval methods, in optimal conditions, intra-nuclear pan and phospho-S129 positive aSyn puncta were observed in cortical neurons and non-neuronal cells in fixed brain sections and in isolated nuclear preparations in all cases examined. Furthermore, an increase in nuclear phospho-S129 positive aSyn immunoreactivity was apparent in DLB cases compared to controls, in both neuronal and non-neuronal cell types. Our initial histological investigations identified that aSynNuc is affected by epitope unmasking methods but present under optimal conditions, and this presence was confirmed by isolation of nuclei and a combined approach of immunoblotting and mass spectrometry, where aSynNuc was approximately tenfold less abundant in the nucleus than cytoplasm. Notably, direct comparison of DLB cases to aged controls identified increased pS129 and higher molecular weight species in the nuclei of DLB cases, suggesting putative pathogenic modifications to aSynNuc in DLB. In summary, using multiple approaches we provide several lines of evidence supporting the presence of aSynNuc in autoptic human brain tissue and, notably, that it is subject to putative pathogenic modifications in DLB that may contribute to the disease phenotype. [ABSTRACT FROM AUTHOR]

Background: Spinal interneurons (INs) relay sensory and motor control information between the brain and body. When this relay circuitry is disrupted from injury or disease, it is devastating to patients due to the lack of native recovery in central nervous system (CNS) tissues. Obtaining a purified population of INs is necessary to better understand their role in normal function and as potential therapies in CNS. The ventral V0 (V0V) INs are excitatory neurons involved in locomotor circuits and are thus of interest for understanding normal and pathological spinal cord function. To achieve scalable amounts of V0V INs, they can be derived from pluripotent sources, such as mouse embryonic stem cells (mESCs), but the resultant culture is heterogenous, obscuring the specific role of V0V INs. This study generated a transgenic mESC line to enrich V0V INs from induced cultures to allow for a scalable, enriched population for future in vitro and in vivo studies. Methods: The transgenic Evx1-PAC mESC line was created by CRISPR-Cas9-mediated insertion of puromycin-N-acetyltransferase (PAC) into the locus of V0V IN marker Evx1. Evx1 and PAC mRNA expression were measured by qPCR. Viability staining helped establish the selection protocol for V0V INs derived from Evx1-PAC mESCs inductions. Immunostaining was used to examine composition of selected inductions. Cultures were maintained up to 30 days to examine maturation by expression of mature/synaptic markers, determined by immunostaining, and functional activity in co-cultures with selected motor neurons (MNs) and V2a INs on microelectrode arrays (MEAs). Results: V0V IN inductions were best selected with 4 µg/mL puromycin on day 10 to 11 and showed reduction of other IN populations and elimination of proliferative cells. Long-term selected cultures were highly neuronal, expressing neuronal nuclear marker NeuN, dendritic marker MAP2, pre-synaptic marker Bassoon, and glutamatergic marker VGLUT2, with some cholinergic VAChT-expressing cells. Functional studies on MEAs showed that co-cultures with MNs or MNs plus V2a INs created neuronal networks with synchronized bursting. Conclusions: Evx1-PAC mESCs can be used to purify V0V IN cultures for largely glutamatergic neurons that can be used in network formation studies or for rodent models requiring transplanted V0V INs. [ABSTRACT FROM AUTHOR]

Background: Maturation is a process that allows synapses to acquire full functionality, optimizing their activity to diverse neural circuits, and defects in synaptic maturation may contribute to neurodevelopmental disorders. Neuroligin-1 (NL1) is a postsynaptic cell adhesion molecule essential for synapse maturation, a role typically attributed to binding to pre-synaptic ligands, the neurexins. However, the pathways underlying the action of NL1 in synaptic maturation are incompletely understood, and some of its previously observed effects seem reminiscent of those described for the neurotrophin brain-derived neurotrophic factor (BDNF). Here, we show that maturational increases in active zone stability and synaptic vesicle recycling rely on the joint action of NL1 and brain-derived neurotrophic factor (BDNF). Results: Applying BDNF to hippocampal neurons in primary cultures or organotypical slice cultures mimicked the effects of overexpressing NL1 on both structural and functional maturation. Overexpressing a NL1 mutant deficient in neurexin binding still induced presynaptic maturation. Like NL1, BDNF increased synaptic vesicle recycling and the augmentation of transmitter release by phorbol esters, both hallmarks of presynaptic maturation. Mimicking the effects of NL1, BDNF also increased the half-life of the active zone marker bassoon at synapses, reflecting increased active zone stability. Overexpressing NL1 increased the expression and synaptic accumulation of BDNF. Inhibiting BDNF signaling pharmacologically or genetically prevented the effects of NL1 on presynaptic maturation. Applying BDNF to NL1-knockout mouse cultures rescued defective presynaptic maturation, indicating that BDNF acts downstream of NL1 and can restore presynaptic maturation at late stages of network development. Conclusions: Our data introduce BDNF as a novel and essential component in a transsynaptic pathway linking NL1-mediated cell adhesion, neurotrophin action, and presynaptic maturation. Our findings connect synaptic cell adhesion and neurotrophin signaling and may provide a therapeutic approach to neurodevelopmental disorders by targeting synapse maturation. [ABSTRACT FROM AUTHOR]

Background: Temperature influences biology at all levels, from altering rates of biochemical reactions to determining sustainability of entire ecosystems. Although extended exposure to elevated temperatures influences organismal phenotypes important for human health, agriculture, and ecology, the molecular mechanisms that drive these responses remain largely unexplored. Prolonged, mild temperature stress (48 h at 28 °C) has been shown to inhibit reproduction in Caenorhabditis elegans without significantly impacting motility or viability. Results: Analysis of molecular responses to chronic stress using RNA-seq uncovers dramatic effects on the transcriptome that are fundamentally distinct from the well-characterized, acute heat shock response (HSR). While a large portion of the genome is differentially expressed ≥ 4-fold after 48 h at 28 °C, the only major class of oogenesis-associated genes affected is the vitellogenin gene family that encodes for yolk proteins (YPs). Whereas YP mRNAs decrease, the proteins accumulate and mislocalize in the pseudocoelomic space as early as 6 h, well before reproduction declines. A trafficking defect in a second, unrelated fluorescent reporter and a decrease in pre-synaptic neuronal signaling indicate that the YP mislocalization is caused by a generalized defect in endocytosis. Molecular chaperones are involved in both endocytosis and refolding damaged proteins. Decreasing levels of the major HSP70 chaperone, HSP-1, causes similar YP trafficking defects in the absence of stress. Conversely, increasing chaperone levels through overexpression of the transcription factor HSF-1 rescues YP trafficking and restores neuronal signaling. Conclusions: These data implicate chaperone titration during chronic stress as a molecular mechanism contributing to endocytic defects that influence multiple aspects of organismal physiology. Notably, HSF-1 overexpression improves recovery of viable offspring after exposure to stress. These findings provide important molecular insights into understanding organismal responses to temperature stress as well as phenotypes associated with chronic protein misfolding. [ABSTRACT FROM AUTHOR]

In addition to providing structural support, caveolin-1 (Cav1), a component of lipid rafts, including caveolae, in the plasma membrane, is involved in various cellular mechanisms, including signal transduction. Although pre-synaptic membrane dynamics and trafficking are essential cellular processes during synaptic vesicle exocytosis/synaptic transmission and synaptic vesicle endocytosis/synaptic retrieval, little is known about the involvement of Cav1 in synaptic vesicle dynamics. Here we demonstrate that synaptic vesicle exocytosis is significantly impaired in Cav1–knockdown (Cav1–KD) neurons. Specifically, the size of the synaptic recycled vesicle pool is modestly decreased in Cav1–KD synapses and the kinetics of synaptic vesicle endocytosis are somewhat slowed. Notably, neurons rescued by triple mutants of Cav1 lacking palmitoylation sites mutants show impairments in both synaptic transmission and retrieval. Collectively, our findings implicate Cav1 in activity-driven synaptic vesicle dynamics—both exocytosis and endocytosis—and demonstrate that palmitoylation of Cav1 is important for this activity. [ABSTRACT FROM AUTHOR]

Background: Physiological disturbances in cortical network excitability and plasticity are established and widespread in amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) patients, including those harbouring the C9ORF72 repeat expansion (C9ORF72RE) mutation – the most common genetic impairment causal to ALS and FTD. Noting that perturbations in cortical function are evidenced pre-symptomatically, and that the cortex is associated with widespread pathology, cortical dysfunction is thought to be an early driver of neurodegenerative disease progression. However, our understanding of how altered network function manifests at the cellular and molecular level is not clear. Methods: To address this we have generated cortical neurons from patient-derived iPSCs harbouring C9ORF72RE mutations, as well as from their isogenic expansion-corrected controls. We have established a model of network activity in these neurons using multi-electrode array electrophysiology. We have then mechanistically examined the physiological processes underpinning network dysfunction using a combination of patch-clamp electrophysiology, immunocytochemistry, pharmacology and transcriptomic profiling. Results: We find that C9ORF72RE causes elevated network burst activity, associated with enhanced synaptic input, yet lower burst duration, attributable to impaired pre-synaptic vesicle dynamics. We also show that the C9ORF72RE is associated with impaired synaptic plasticity. Moreover, RNA-seq analysis revealed dysregulated molecular pathways impacting on synaptic function. All molecular, cellular and network deficits are rescued by CRISPR/Cas9 correction of C9ORF72RE. Our study provides a mechanistic view of the early dysregulated processes that underpin cortical network dysfunction in ALS-FTD. Conclusion: These findings suggest synaptic pathophysiology is widespread in ALS-FTD and has an early and fundamental role in driving altered network function that is thought to contribute to neurodegenerative processes in these patients. The overall importance is the identification of previously unidentified defects in pre and postsynaptic compartments affecting synaptic plasticity, synaptic vesicle stores, and network propagation, which directly impact upon cortical function. [ABSTRACT FROM AUTHOR]

Cognitive dysfunction occurs in greater than 50% of individuals with multiple sclerosis (MS). Hippocampal demyelination is a prominent feature of postmortem MS brains and hippocampal atrophy correlates with cognitive decline in MS patients. Cellular and molecular mechanisms responsible for neuronal dysfunction in demyelinated hippocampi are not fully understood. Here we investigate a mouse model of hippocampal demyelination where twelve weeks of treatment with the oligodendrocyte toxin, cuprizone, demyelinates over 90% of the hippocampus and causes decreased memory/learning. Long-term potentiation (LTP) of hippocampal CA1 pyramidal neurons is considered to be a major cellular readout of learning and memory in the mammalian brain. In acute slices, we establish that hippocampal demyelination abolishes LTP and excitatory post-synaptic potentials of CA1 neurons, while pre-synaptic function of Schaeffer collateral fibers is preserved. Demyelination also reduced Ca2+-mediated firing of hippocampal neurons in vivo. Using three-dimensional electron microscopy, we investigated the number, shape (mushroom, stubby, thin), and post-synaptic densities (PSDs) of dendritic spines that facilitate LTP. Hippocampal demyelination did not alter the number of dendritic spines. Surprisingly, dendritic spines appeared to be more mature in demyelinated hippocampi, with a significant increase in mushroom-shaped spines, more perforated PSDs, and more astrocyte participation in the tripartite synapse. RNA sequencing experiments identified 400 altered transcripts in demyelinated hippocampi. Gene transcripts that regulate myelination, synaptic signaling, astrocyte function, and innate immunity were altered in demyelinated hippocampi. Hippocampal remyelination rescued synaptic transmission, LTP, and the majority of gene transcript changes. We establish that CA1 neurons projecting demyelinated axons silence their dendritic spines and hibernate in a state that may protect the demyelinated axon and facilitates functional recovery following remyelination. [ABSTRACT FROM AUTHOR]

Background: Significant developments in stem cell therapy for Parkinson's disease (PD) have already been achieved; however, methods for reliable assessment of dopamine neuron maturation in vivo are lacking. Establishing the efficacy of new cellular therapies using non-invasive methodologies will be critical for future regulatory approval and application. The current study examines the utility of neuroimaging to characterise the in vivo maturation, innervation and functional dopamine release of transplanted human embryonic stem cell-derived midbrain dopaminergic neurons (hESC-mDAs) in a preclinical model of PD. Methods: Female NIH RNu rats received a unilateral stereotaxic injection of 6-OHDA into the left medial forebrain bundle to create the PD lesion. hESC-mDA cell and sham transplantations were carried out 1 month post-lesion, with treated animals receiving approximately 4 × 105 cells per transplantation. Behavioural analysis, [18F]FBCTT and [18F]fallypride microPET/CT, was conducted at 1, 3 and 6 months post-transplantation and compared with histological characterisation at 6 months. Results: PET imaging revealed transplant survival and maturation into functional dopaminergic neurons. [18F]FBCTT-PET/CT dopamine transporter (DAT) imaging demonstrated pre-synaptic restoration and [18F]fallypride-PET/CT indicated functional dopamine release, whilst amphetamine-induced rotation showed significant behavioural recovery. Moreover, histology revealed that the grafted cells matured differently in vivo producing high- and low-tyrosine hydroxylase (TH) expressing cohorts, and only [18F]FBCTT uptake was well correlated with differentiation. Conclusions: This study provides further evidence for the value of in vivo functional imaging for the assessment of cell therapies and highlights the utility of DAT imaging for the determination of early post-transplant cell maturation and differentiation of hESC-mDAs. [ABSTRACT FROM AUTHOR]

Background: Acaricide resistance is a central problem for the control of the cattle tick Rhipicephalus microplus. The physiological effects and phenotypes of the mutations that cause acaricide resistance are not always well understood or characterized. Single nucleotide polymorphisms (SNPs) that confer cypermethrin knockdown resistance (kdr) have been reported in R. microplus. These SNPs have been associated and correlated with pyrethroid resistance although there is no direct physiological evidence that their presence does confer kdr in this organism. Methods: Resistant and susceptible strain resistance profiles were obtained using the larval packet discriminating dose assay. The relevant genomic regions of the para-sodium channel were amplified using standard PCR; SNPs were detected by sequencing the corresponding amplicons. Ovary response to cypermethrin exposure/treatment was evaluated using videometrical analysis. Results: We found that the pyrethroid resistance trait is stable in a resistant reference strain after years without selection, suggesting that the resistance conferring mutations are fixed in the population. In this strain, a change in the structure of the pre-synaptic para-sodium channel caused by the G184C, the C190A and the T2134A SNPs appears to confer resistance. These mutations are absent in the susceptible strain used as control. We demonstrate that cypermethrin blocks ovary contraction in cypermethrin-susceptible ticks. We also show that ovaries from organisms that carry the kdr associated SNPs still contract at cypermethrin concentrations that completely block ovary contraction in the susceptible strain. The configuration of the experimental system excludes a xenobiotic detoxification mechanism. Conclusions: This is the first report that presents physiological evidence that the presence of the G184C, the C190A, and the T2134A mutations in the para-sodium channel correlates with maintaining muscle contractility in R. microplus exposed to cypermethrin. These SNPs may confer cypermethrin resistance in this organism by avoiding presynaptic blockage, inhibiting the flaccid muscle paralysis characteristic of this acaricide. The videometric assay that we previously validated can be used to detect more rapidly than other assays that involve larval mortality kdr-like cypermethrin resistant tick strains, permitting to directly assay adult pre-engorged females after they are collected on the field without waiting until eggs are laid and larvae eclose. [ABSTRACT FROM AUTHOR]

Background: α-Synuclein (α-syn) is a pre-synaptic protein which progressively accumulates in neuronal and non-neuronal cells in neurodegenerative diseases such as Parkinson's disease (PD), dementia with Lewy bodies (DLB), and multiple system atrophy. Recent evidence suggests that aberrant immune activation may be involved in neurodegeneration in PD/DLB. While previous studies have often focused on the microglial responses, less is known about the role of the peripheral immune system in these disorders.Methods: To understand the involvement of the peripheral immune system in PD/DLB, we evaluated T cell populations in the brains of α-syn transgenic (tg) mice (e.g., Thy1 promoter line 61) and DLB patients.Results: Immunohistochemical analysis showed perivascular and parenchymal infiltration by CD3+/CD4+ helper T cells, but not cytotoxic T cells (CD3+/CD8+) or B cells (CD20+), in the neocortex, hippocampus, and striatum of α-syn tg mice. CD3+ cells were found in close proximity to the processes of activated astroglia, particularly in areas of the brain with significant astrogliosis, microgliosis, and expression of pro-inflammatory cytokines. In addition, a subset of CD3+ cells co-expressed interferon γ. Flow cytometric analysis of immune cells in the brains of α-syn tg mice revealed that CD1d-tet+ T cells were also increased in the brains of α-syn tg mice suggestive of natural killer T cells. In post-mortem DLB brains, we similarly detected increased numbers of infiltrating CD3+/CD4+ T cells in close proximity with blood vessels.Conclusion: These results suggest that infiltrating adaptive immune cells play an important role in neuroinflammation and neurodegeneration in synucleinopathies and that modulating peripheral T cells may be a viable therapeutic strategy for PD/DLB. [ABSTRACT FROM AUTHOR]

Background and aim: Human dental pulp stem cells (hDPSCs) constitute a promising alternative for central nervous system (CNS) cell therapy. Unlike other human stem cells, hDPSCs can be differentiated, without genetic modification, to neural cells that secrete neuroprotective factors. However, a better understanding of their real capacity to give rise to functional neurons and integrate into synaptic networks is still needed. For that, ex vivo differentiation protocols must be refined, especially to avoid the use of fetal animal serum. The aim of our study is to improve existing differentiation protocols of hDPSCs into neuron-like cells. Methods: We compared the effects of the (1) absence or presence of fetal serum during the initial expansion phase as a step prior to switching cultures to neurodifferentiation media. We (2) improved hDPSC neurodifferentiation by adding retinoic acid (RA) and potassium chloride (KCl) pulses for 21 or 60 days and characterized the results by immunofluorescence, digital morphometric analysis, RT-qPCR and electrophysiology. Results: We found that neural markers like Nestin, GFAP, S100β and p75NTR were expressed differently in neurodifferentiated hDPSC cultures depending on the presence or absence of serum during the initial cell expansion phase. In addition, hDPSCs previously grown as spheroids in serum-free medium exhibited in vitro expression of neuronal markers such as doublecortin (DCX), neuronal nuclear antigen (NeuN), Ankyrin-G and MAP2 after neurodifferentiation. Presynaptic vGLUT2, Synapsin-I, and excitatory glutamatergic and inhibitory GABAergic postsynaptic scaffold proteins and receptor subunits were also present in these neurodifferentiated hDPSCs. Treatment with KCl and RA increased the amount of both voltage-gated Na+ and K+ channel subunits in neurodifferentiated hDPSCs at the transcript level. Consistently, these cells displayed voltage-dependent K+ and TTX-sensitive Na+ currents as well as spontaneous electrophysiological activity and repetitive neuronal action potentials with a full baseline potential recovery. Conclusion: Our study demonstrates that hDPSCs can be differentiated to neuronal-like cells that display functional excitability and thus evidence the potential of these easily accessible human stem cells for nerve tissue engineering. These results highlight the importance of choosing an appropriate culture protocol to successfully neurodifferentiate hDPSCs. [ABSTRACT FROM AUTHOR]

The brain presents various structural and functional sex differences, for which multiple factors are attributed: genetic, epigenetic, metabolic, and hormonal. While biological sex is determined by both sex chromosomes and sex hormones, little is known about how these two factors interact to establish this dimorphism. Sex differences in the brain also affect its resident immune cells, microglia, which actively survey the brain parenchyma and interact with sex hormones throughout life. However, microglial differences in density and distribution, morphology and ultrastructural patterns in physiological conditions during adulthood are largely unknown. Here, we investigated these aforementioned properties of microglia using the Four Core Genotypes (FCG) model, which allows for an independent assessment of gonadal hormones and sex chromosomal effects in four conditions: FCG XX and Tg XY− (both ovaries); Tg XXSry and Tg XYSry (both testes). We also compared the FCG results with XX and XY wild-type (WT) mice. In adult mice, we focused our investigation on the ventral hippocampus across different layers: CA1 stratum radiatum (Rad) and CA1 stratum lacunosum-moleculare (LMol), as well as the dentate gyrus polymorphic layer (PoDG). Double immunostaining for Iba1 and TMEM119 revealed that microglial density is influenced by both sex chromosomes and sex hormones. We show in the Rad and LMol that microglia are denser in FCG XX compared to Tg XYSry mice, however, microglia were densest in WT XX mice. In the PoDG, ovarian animals had increased microglial density compared to testes animals. Additionally, microglial morphology was modulated by a complex interaction between hormones and chromosomes, affecting both their cellular soma and arborization across the hippocampal layers. Moreover, ultrastructural analysis showed that microglia in WT animals make overall more contacts with pre- and post-synaptic elements than in FCG animals. Lastly, microglial markers of cellular stress, including mitochondrion elongation, and dilation of the endoplasmic reticulum and Golgi apparatus, were mostly chromosomally driven. Overall, we characterized different aspects of microglial properties during normal physiological conditions that were found to be shaped by sex chromosomes and sex hormones, shading more light onto how sex differences affect the brain immunity at steady-state. [ABSTRACT FROM AUTHOR]

Delta-opioid receptors (δ-ORs) are known to be involved in associative learning and modulating motivational states. We wanted to study if they were also involved in naturally-occurring reinforcement learning behaviors such as vocal learning, using the zebra finch model system. Zebra finches learn to vocalize early in development and song learning in males is affected by factors such as the social environment and internal reward, both of which are modulated by endogenous opioids. Pairs of juvenile male siblings (35-day-old) were systemically administered a δ-OR-selective antagonist naltrindole or vehicle (controls) for a period of 10 days. The acoustic structure of songs differed across treated and control groups at adulthood (120 days). Naltrindole-treated birds had a significantly lower pitch, mean frequency, and frequency modulation than controls, whereas there was no difference in the number of songs in naltrindole-treated and control siblings. Since the opioid and dopaminergic systems interact, we decided to study whether blocking δ-ORs during the sensitive period led to changes in dopaminoceptive neurons in Area X, a song control nucleus in the basal ganglia. Interestingly, compared with controls, naltrindole-treated birds had higher numbers of DARPP-32-positive medium spiny neurons and potentially excitatory synapses in Area X. We show that manipulating δ-OR signaling during the learning phase resulted in alterations in the acoustic features of song and had long term effects on dopaminergic targets within the basal ganglia in adulthood. Our results suggest that endogenous opioids regulate the development of cognitive processes and the underlying neural circuitry during the sensitive period for learning. [ABSTRACT FROM AUTHOR]

Leucine-rich repeat kinase 2 (LRRK2) is a ROCO family member which its mutation is closely related with Parkinson's disease, and LRRK2 is widely involved into the regulation of autophagy, vesicle transport and neuronal proliferation. However, the roles of LRRK2 during mammalian oocyte maturation are still largely unclear. In present study, we disturbed the activity of LRRK2 and showed its essential roles in porcine oocytes. We showed that LRRK2 stably expressed during oocyte maturation, and the loss of LRRK2 activity disturbed cumulus expansion and oocyte polar body extrusion, indicating its involvement into oocyte maturation. Further analysis indicated that LRRK2 was related with cytoskeleton dynamics since its inhibition caused spindle organization defect and chromosome misalignment, and both cytoplasmic and cortex actin decreased. Moreover, LRRK2 co-localized with mitochondria and its activity was essential for mitochondria distribution. Loss of LRRK2 activity altered the TMRE level, which ultimately induced ROS-related oxidative stress. Taken together, our data suggested the important roles of LRRK2 on mammalian oocyte maturation through its effects on cytoskeleton dynamics and mitochondria functions. [ABSTRACT FROM AUTHOR]

Parkinson's disease (PD) is a neurodegenerative disease affecting millions of people around the world. Conventional PD detection algorithms are generally based on first and second-generation artificial neural network (ANN) models which consume high energy and have complex architecture. Considering these limitations, a time-varying synaptic efficacy function based leaky-integrate and fire neuron model, called SEFRON is used for the detection of PD. SEFRON explores the advantages of Spiking Neural Network (SNN) which is suitable for neuromorphic devices. To evaluate the performance of SEFRON, 2 publicly available standard datasets, namely (1) UCI: Oxford Parkinson's Disease Detection Dataset and (2) UCI: Parkinson Dataset with replicated acoustic features are used. The performance is compared with other well-known neural network models: Multilayer Perceptron Neural Network (MLP-NN), Radial Basis Function Neural Network (RBF-NN), Recurrent Neural Network (RNN) and Long short-term memory (LSTM). The experimental results demonstrate that the SEFRON classifier achieves a maximum accuracy of 100% and an average accuracy of 99.49% on dataset 1. For dataset 2, it attains a peak accuracy of 94% and an average accuracy of 91.94%, outperforming the other classifiers in both cases. From the performance, it is proved that the presented model can help to develop a robust automated PD detection device that can assist the physicians to diagnose the disease at its early stage. [ABSTRACT FROM AUTHOR]

Eating disorders (EDs) are a group of debilitating mental illnesses characterized by maladaptive eating behaviors and severe cognitive-emotional dysfunction, directly affecting 1–3% of the population. Standard treatments are not effective in approximately one third of ED cases, representing the need for scientific advancement. There is emerging evidence for the safety and efficacy of psilocybin-assisted psychotherapy (PAP) to improve treatment outcomes in individuals with EDs. However, the limited knowledge of the neurobiological mechanisms underlying the therapeutic effects of PAP restricts the ability to confirm its clinical utility. This narrative review presents an overview of methodologies used to elucidate the pathophysiological mechanisms of EDs or the effects of psilocybin that could be employed to probe the neurobiological correlates of PAP in EDs, including magnetic resonance imaging and molecular neuroimaging techniques, electrophysiological approaches, and neuroplasticity markers. Finally, the implications of these methodologies are described in relation to the unique features of the psychedelic study design, challenges, limitations, and future directions to advance the field. This paper represents a valuable resource for scientists during study conceptualization and design phases and stimulates advancement in the identification of effective therapeutic interventions for EDs. Plain English Summary: Eating disorders (EDs) are serious mental health conditions that impact eating behaviors, thoughts, and emotions, directly affecting up to 3% of people worldwide. Current treatments are not effective in about one third of cases, highlighting the need for new approaches. Psilocybin-assisted psychotherapy (PAP) is an emerging treatment option that shows promise for improving outcomes in people with EDs. However, there is a lack of understanding for the mechanisms in which PAP may support recovery, making it difficult to confirm its benefits. This review presents several research methods that could help uncover how PAP influences the brain in EDs, including neuroimaging approaches and neuroplasticity markers. The challenges of incorporating these methods into the psychedelic study design and future research directions are also discussed. Together, this review presents a valuable resource for scientists and stimulates advancements in the development of more effective treatments for EDs. [ABSTRACT FROM AUTHOR]

Cranial radiation therapy (RT) for brain cancers is often associated with the development of radiation-induced cognitive dysfunction (RICD). RICD significantly impacts the quality of life for cancer survivors, highlighting an unmet medical need. Previous human studies revealed a marked reduction in plasma brain-derived neurotrophic factor (BDNF) post-chronic chemotherapy, linking this decline to a substantial cognitive dysfunction among cancer survivors. Moreover, riluzole (RZ)-mediated increased BDNF in vivo in the chemotherapy-exposed mice reversed cognitive decline. RZ is an FDA-approved medication for ALS known to increase BDNF in vivo. In an effort to mitigate the detrimental effects of RT-induced BDNF decline in RICD, we tested the efficacy of RZ in a cranially irradiated (9 Gy) adult mouse model. Notably, RT-exposed mice exhibited significantly reduced hippocampal BDNF, accompanied by increased neuroinflammation, loss of neuronal plasticity-related immediate early gene product, cFos, and synaptic density. Spatial transcriptomic profiling comparing the RT + Vehicle with the RT + RZ group showed gene expression signatures of neuroprotection of hippocampal excitatory neurons post-RZ. RT-exposed mice performed poorly on learning and memory, and memory consolidation tasks. However, irradiated mice receiving RZ (13 mg/kg, drinking water) for 6–7 weeks showed a significant improvement in cognitive function compared to RT-exposed mice receiving vehicle. Dual-immunofluorescence staining, spatial transcriptomics, and biochemical assessment of RZ-treated irradiated brains demonstrated preservation of synaptic integrity and mature neuronal plasticity but not neurogenesis and reduced neuroinflammation concurrent with elevated BDNF levels and transcripts compared to vehicle-treated irradiated brains. In summary, oral administration of RZ represents a viable and translationally feasible neuroprotective approach against RICD. [ABSTRACT FROM AUTHOR]

Misfolding of normal prion protein (PrPC) to pathological isoforms (prions) causes prion diseases (PrDs) with clinical manifestations including cognitive decline and mood-related behavioral changes. Cognition and mood are linked to the neurophysiology of the limbic system. Little is known about how the disease affects the synaptic activity in brain parts associated with this system. We hypothesize that the dysfunction of synaptic transmission in the limbic regions correlates with the onset of reduced cognition and behavioral deficits. Here, we studied how prion infection in mice disrupts the synaptic function in three limbic regions, the hippocampus, hypothalamus, and amygdala, at a pre-clinical stage (mid-incubation period) and early clinical onset. PrD caused calcium flux dysregulation associated with lesser spontaneous synchronous neuronal firing and slowing neural oscillation at the pre-clinical stage in the hippocampal CA1, ventral medial hypothalamus, and basolateral amygdala (BLA). At clinical onset, synaptic transmission and synaptic plasticity became significantly disrupted. This correlated with a substantial depletion of the soluble prion protein, loss of total synapses, abnormal neurotransmitter levels and synaptic release, decline in synaptic vesicle recycling, and cytoskeletal damage. Further, the amygdala exhibited distinct disease-related changes in synaptic morphology and physiology compared with the other regions, but generally to a lesser degree, demonstrating how different rates of damage in the limbic system influence the evolution of clinical disease. Overall, PrD causes synaptic damage in three essential limbic regions starting at a preclinical stage and resulting in synaptic plasticity dysfunction correlated with early disease signs. Therapeutic drugs that alleviate these early neuronal dysfunctions may significantly delay clinical onset. [ABSTRACT FROM AUTHOR]

Introduction: Myocardial dissection is a rare complication of ischaemic heart disease. It occurs when a haematoma forms within the cardiac muscle, either due to an endocardial rupture or rupture of an intra-myocardial vessel. Higher ventricular wall tension and reduced myocardial tensile strength increase the risk of dissection. We describe a young male who developed a myocardial dissection following an ST elevation infarction. We explore the possible pathophysiological connection between myocardial dissection and his amphetamine use. Case presentation: A 37-year-old Sri Lankan patient presented with progressively worsening heart failure for two weeks. One month before the presentation, he had developed an ischaemic chest pain, for which he had not sought medical advice. He was abusing inhalational heroin, crystal methamphetamines and cigarette smoke daily for five years. On examination, the patient had a blood pressure of 90/60 mmHg and a pulse rate of 110 beats per minute. The cardiac apex was deviated. The jugular venous pressure was elevated, bilateral pitting ankle and pulmonary oedema were present. The ECG had Q-ST elevations in the lateral leads. Serum troponin was elevated. A transthoracic echocardiogram revealed a poorly functioning dilated left ventricle with a mass within the myocardial apex. Cardiac MRI established that the mass was an intra-myocardial haematoma. A coronary angiogram demonstrated a critical plaque stenosis at the mid left-anterior-descending artery with poor distal flow. The patient did not have HIV or infective endocarditis. We treated the patient with diuretics and guideline-directed medical therapy for heart failure with reduced ejection fraction. We did not attempt surgical repair as the dissection was non-expanding, and the patient was at a high risk of operative complications. Conclusions: Myocardial dissection with aneurysm formation is a rare complication of ischaemic heart disease. Methamphetamines enhance the risk of myocardial dissection by inducing myocardial inflammation, causing a dilated cardiomyopathy and increasing the left ventricular pressures. [ABSTRACT FROM AUTHOR]

Background: In fly brains, the Drosophila Adar (adenosine deaminase acting on RNA) enzyme edits hundreds of transcripts to generate edited isoforms of encoded proteins. Nearly all editing events are absent or less efficient in larvae but increase at metamorphosis; the larger number and higher levels of editing suggest editing is most required when the brain is most complex. This idea is consistent with the fact that Adar mutations affect the adult brain most dramatically. However, it is unknown whether Drosophila Adar RNA editing events mediate some coherent physiological effect. To address this question, we performed a genetic screen for suppressors of Adar mutant defects. Adar5G1 null mutant flies are partially viable, severely locomotion defective, aberrantly accumulate axonal neurotransmitter pre-synaptic vesicles and associated proteins, and develop an age-dependent vacuolar brain neurodegeneration. Results: A genetic screen revealed suppression of all Adar5G1 mutant phenotypes tested by reduced dosage of the Tor gene, which encodes a pro-growth kinase that increases translation and reduces autophagy in well-fed conditions. Suppression of Adar5G1 phenotypes by reduced Tor is due to increased autophagy; overexpression of Atg5, which increases canonical autophagy initiation, reduces aberrant accumulation of synaptic vesicle proteins and suppresses all Adar mutant phenotypes tested. Endosomal microautophagy (eMI) is another Tor-inhibited autophagy pathway involved in synaptic homeostasis in Drosophila. Increased expression of the key eMI protein Hsc70-4 also reduces aberrant accumulation of synaptic vesicle proteins and suppresses all Adar5G1 mutant phenotypes tested. Conclusions: These findings link Drosophila Adar mutant synaptic and neurotransmission defects to more general cellular defects in autophagy; presumably, edited isoforms of CNS proteins are required for optimum synaptic response capabilities in the brain during the behaviorally complex adult life stage. [ABSTRACT FROM AUTHOR]

Background: Olfactomedin-1 (Olfm1; also known as Noelin or Pancortin) is a highly-expressed secreted brain and retina protein and its four isoforms have different roles in nervous system development and function. Structural studies showed that the long Olfm1 isoform BMZ forms a disulfide-linked tetramer with a V-shaped architecture. The tips of the Olfm1 "V" each consist of two C-terminal ß-propeller domains that enclose a calcium binding site. Functional characterisation of Olfm1 may be aided by new biochemical tools derived from these core structural elements. Results: Here we present the production, purification and structural analysis of three novel monomeric, dimeric and tetrameric forms of mammalian Olfm1 for functional studies. We characterise these constructs structurally by high-resolution X-ray crystallography and small-angle X-ray scattering. The crystal structure of the Olfm1 ß-propeller domain (to 1.25 Å) represents the highest-resolution structure of an olfactomedin family member to date, revealing features such as a hydrophilic tunnel containing water molecules running into the core of the domain where the calcium binding site resides. The shorter Olfactomedin-1 isoform BMY is a disulfide-linked tetramer with a shape similar to the corresponding region in the longer BMZ isoform. Conclusions: These recombinantly-expressed protein tools should assist future studies, for example of biophysical, electrophysiological or morphological nature, to help elucidate the functions of Olfm1 in the mature mammalian brain. The control over the oligomeric state of Olfm1 provides a firm basis to better understand the role of Olfm1 in the (trans-synaptic) tethering or avidity-mediated clustering of synaptic receptors such as post-synaptic AMPA receptors and pre-synaptic amyloid precursor protein. In addition, the variation in domain composition of these protein tools provides a means to dissect the Olfm1 regions important for receptor binding. [ABSTRACT FROM AUTHOR]

Spinal and bulbar muscular atrophy (SBMA) is an X-linked, neuromuscular neurodegenerative disease for which there is no cure. The disease is characterized by a selective decrease in fast-muscle power (e.g., tongue pressure, grip strength) accompanied by a selective loss of fast-twitch muscle fibers. However, the relationship between neuromuscular junction (NMJ) pathology and fast-twitch motor unit vulnerability has yet to be explored. In this study, we used a cross-model comparison of two mouse models of SBMA to evaluate neuromuscular junction pathology, glycolytic-to-oxidative fiber-type switching, and cytoskeletal alterations in pre- and postsynaptic termini of tibialis anterior (TA), gastrocnemius, and soleus hindlimb muscles. We observed significantly increased NMJ and myofiber pathology in fast-twitch, glycolytic motor units of the TA and gastrocnemius compared to slow-twitch, oxidative motor units of the soleus, as seen by decreased pre- and post-synaptic membrane area, decreased pre- and post-synaptic membrane colocalization, increased acetylcholine receptor compactness, a decrease in endplate area and complexity, and deficits in neurofilament heavy chain. Our data also show evidence for metabolic dysregulation and myofiber atrophy that correlate with severity of NMJ pathology. We propose a model in which the dynamic communicative relationship between the motor neuron and muscle, along with the developmental subtype of the muscle, promotes motor unit subtype specific vulnerability, metabolic alterations, and NMJ pathology. [ABSTRACT FROM AUTHOR]

Highlights: The inaugural Clinical and Scientific Conference on Adenylosuccinate Synthetase 1 (ADSS1) myopathy was held on June 3, 2024, at the National Institutes of Health (NIH) National Center for Advancing Translational Sciences (NCATS) in Rockville, Maryland, USA. ADSS1 myopathy is an ultra-rare, inherited neuromuscular disease. Features of geographical patient clusters in South Korea, Japan, India and the United States of America were characterised and discussed. Pre-clinical animal and cell-based models were discussed, providing unique insight into disease pathogenesis. The biochemical pathogenesis was discussed, and potential therapeutic targets identified. Potential clinical and pre-clinical biomarkers were discussed. An ADSS1 myopathy consortium was established and a roadmap for therapeutic development created. [ABSTRACT FROM AUTHOR]

Background: Huntington's disease (HD) is a genetic neurological disorder predominantly characterised by the progressive loss of GABAergic medium spiny neurons in the striatum resulting in motor dysfunction. One potential strategy for the treatment of HD is the development of cell replacement therapies to restore neuronal circuitry and function by the replacement of lost neurons. We propose the generation of lineage-specific human lateral ganglionic eminence precursors (hiLGEP) using direct reprogramming technology provides a novel and clinically viable cell source for cell replacement therapy for HD. Methods: hiLGEPs were derived by direct reprogramming of adult human dermal fibroblasts (aHDFs) using chemically modified mRNA (cmRNA) and a defined reprogramming medium. hiLGEPs were differentiated in vitro using an optimised striatal differentiation medium. Acquisition of a striatal precursor and neural cell fate was assessed through gene expression and immunocytochemical analysis of key markers. hiLGEP-derived striatal neuron functionality in vitro was demonstrated by calcium imaging using Cal-520. To investigate the ability for hiLGEP to survive, differentiate and functionally integrate in vivo, we transplanted hiLGEPs into the striatum of quinolinic acid (QA)-lesioned rats and performed behavioural assessment using the cylinder test over the course of 14 weeks. Survival and differentiation of hiLGEPs was assessed at 8 and 14-weeks post-transplant by immunohistochemical analysis. Results: We demonstrate the capability to generate hiLGEPs from aHDFs using cmRNA encoding the pro-neural genes SOX2 and PAX6, combined with a reprogramming medium containing Gö6983, Y-27,632, N-2 and Activin A. hiLGEPs generated functional DARPP32 + neurons following 14 days of culture in BrainPhys™ media supplemented with dorsomorphin and Activin A. We investigated the ability for hiLGEPs to survive transplantation, differentiate to medium spiny-like striatal neurons and improve motor function in the QA lesion rat model of HD. Fourteen weeks after transplantation, we observed STEM121 + neurons co-expressing MAP2, DARPP32, GAD65/67, or GABA. Rats transplanted with hiLGEPs also demonstrated reduction in motor function impairment as determined by spontaneous exploratory forelimb use when compared to saline transplanted animals. Conclusion: This study provides proof-of-concept and demonstrates for the first time that aHDFs can be directly reprogrammed to hiLGEPs which survive transplantation, undergo neuronal differentiation to generate medium spiny-like striatal neurons, and reduce functional impairment in the QA lesion rat model of HD. Significance statement: The present study reports for the first time that human lateral ganglionic eminence precursor (hiLGEP) cells directly reprogrammed from adult human fibroblasts using chemically modified mRNA can survive transplantation into the quinolinic acid-lesioned rat striatum and generate medium spiny striatal neurons. Most importantly, the authors show that transplantation of directly reprogrammed hiLGEPs restores motor function impairment by 14 weeks post-transplantation. This work provides proof of concept and demonstrates that directly reprogrammed hiLGEPs offer an effective and clinically viable cell source for cell replacement therapy to treat Huntington's disease. [ABSTRACT FROM AUTHOR]

Background: Defects in the ataxin-2 (ATXN-2) protein and CAG trinucleotide repeat expansion in its coding gene, Atxn-2, cause the neurodegenerative disorder spinocerebellar ataxia type 2 (SCA2). While clinical studies suggest potential benefits of human-derived mesenchymal stem cells (hMSCs) for treating various ataxias, the exact mechanisms underlying their therapeutic effects and interaction with host tissue to stimulate neurotrophin expression remain unclear specifically in the context of SCA2. Methods: Human bone marrow-derived MSCs (hMSCs) were injected into the cisterna magna of 26-week-old wild-type and SCA2 mice. Mice were assessed for impaired motor coordination using the accelerating rotarod, open field test, and composite phenotype scoring. At 50 weeks, the cerebellum vermis was harvested for protein assessment and immunohistochemical analysis. Results: Significant loss of NeuN and calbindin was observed in 25-week-old SCA2 mice. However, after receiving multiple injections of hMSCs starting at 26 weeks of age, these mice exhibited a significant improvement in abnormal motor performance and a protective effect on Purkinje cells. This beneficial effect persisted until the mice reached 50 weeks of age, at which point they were sacrificed to study further mechanistic events triggered by the administration of hMSCs. Calbindin-positive cells in the Purkinje cell layer expressed bone-derived neurotrophic factor after hMSC administration, contributing to the protection of cerebellar neurons from cell death. Conclusion: In conclusion, repeated administration of hMSCs shows promise in alleviating SCA2 symptoms by preserving Purkinje cells, improving neurotrophic support, and reducing inflammation, ultimately leading to the preservation of locomotor function in SCA2 mice. [ABSTRACT FROM AUTHOR]

Postoperative cognitive dysfunction (POCD) is a frequent neurological complication encountered during the perioperative period with unclear mechanisms and no effective treatments. Recent research into the pathogenesis of POCD has primarily focused on neuroinflammation, oxidative stress, changes in neural synaptic plasticity and neurotransmitter imbalances. Given the high-energy metabolism of neurons and their critical dependency on mitochondria, mitochondrial dysfunction directly affects neuronal function. Additionally, as the primary organelles generating reactive oxygen species, mitochondria are closely linked to the pathological processes of neuroinflammation. Surgery and anesthesia can induce mitochondrial dysfunction, increase mitochondrial oxidative stress, and disrupt mitochondrial quality-control mechanisms via various pathways, hence serving as key initiators of the POCD pathological process. We conducted a review on the role and potential mechanisms of mitochondria in postoperative cognitive dysfunction by consulting relevant literature from the PubMed and EMBASE databases spanning the past 25 years. Our findings indicate that surgery and anesthesia can inhibit mitochondrial respiration, thereby reducing ATP production, decreasing mitochondrial membrane potential, promoting mitochondrial fission, inducing mitochondrial calcium buffering abnormalities and iron accumulation, inhibiting mitophagy, and increasing mitochondrial oxidative stress. Mitochondrial dysfunction and damage can ultimately lead to impaired neuronal function, abnormal synaptic transmission, impaired synthesis and release of neurotransmitters, and even neuronal death, resulting in cognitive dysfunction. Targeted mitochondrial therapies have shown positive outcomes, holding promise as a novel treatment for POCD. [ABSTRACT FROM AUTHOR]

Background: Ferroptosis represents a nonapoptotic type of programmed cell death induced by excessive intracellular iron accumulation. Ferroptosis is an essential driver of the pathogenesis of Alzheimer's disease (AD). Tetrahedral framework nucleic acids (tFNAs) are a novel type of nanoparticle with superior antiapoptotic capacity and excellent biocompatibility. However, the effect of tFNAs on Aβ triggered ferroptosis, cognitive and synaptic impairments in AD remains unknown. Methods: N2a cells were treated with Aβ combined with/without tFNAs. Cell viability and levels of Fe2+, lipid peroxidation, MDA, LDH, and GSH were examined. RNA sequencing was applied to explore dysregulated ferroptosis related genes. Seven-month-old APP/PS1 mice were intranasally administrated with tFNAs for two weeks. Fluorescence imaging was used to detect the tFNAs distribution in the brain. Novel object recognition (NOR) test followed by Morris water maze (MWM) was used to test the learning and memory performance of mice. Golgi staining, Western blot, and immunofluorescence staining were used to examine synaptic plasticity. Results: tFNAs promoted cell viability and GSH levels, reduced the levels of Fe2+, lipid peroxidation, MDA, and LDH in N2a cells treated with Aβ. RNA sequencing revealed that tFNAs reversed the promotive effect of Aβ on ferroptosis driver Atf3 gene and suppressive effect on ferroptosis suppressors Rrm2 and Furin genes. Fluorescence imaging confirmed the brain infiltration of tFNAs. tFNAs rescued synaptic and memory impairments, and ferroptosis in seven-month-old APP/PS1 mice. Conclusions: Collectively, tFNAs inhibited Aβ-mediated ferroptosis and ameliorated cognitive and synaptic impairments in AD mice. tFNAs may serve as novel option to deal with AD. [ABSTRACT FROM AUTHOR]

Background: Cerebral palsy (CP) is considered the most prevalent developmental motor disorder in children. There is a need for training programs that enhance motor abilities and normalize function from an early age. Previous studies report improved motor outcomes in dance interventions for CP. Investigating the neurophysiological mechanisms underlying such improvements is necessary for efficient and safe intervention design. This study reports changes in stretch reflex responses as the primary neurophysiological motor outcome of a targeted ballet class intervention. Results: A case series of participants with mixed spastic and dyskinetic CP (n = 4, mean age = 12.5 years, SD = 6.9S years, three female, one male) who learned ballet technique in a course of one-hour classes twice per week for six weeks is presented. Changes in stretch reflex responses and in clinical motor tests as secondary outcomes were observed after the course and at one-month follow-up. Quantitative measures of elbow or ankle stretch reflex were obtained using electromyography and electrogoniometry. The joint angle of the stretch reflex onset varied across velocities of stretch, and its variability decreased after the intervention. Within-subject tests of the central tendency of stretch reflex angle coefficients of variation and frequency distribution demonstrated significant changes (p-values < 0.05). Secondary outcomes included the Quality of Upper Extremity Skills Test (QUEST), Pediatric Balance Scale (PBS), Modified Tardieu Scale (MTS), Dyskinesia Impairment Scale (DIS), and Selective Control Assessment of the Lower Extremity (SCALE). All the participants demonstrated improvements larger than the minimal clinical important difference (MCID) or the smallest detectable difference (SDD), as applicable. Conclusions: Evidence of changes in the stretch reflex responses in these four cases of mixed CP was observed. The observed variability in the stretch reflex responses may be due to the dyskinetic component of the mixed CP presentations. More studies with a larger sample size and longer duration of learning and practice of ballet technique are necessary to establish the extent of possible modulation and adaptation of the stretch reflex response as a neurophysiological basis for observed improvements in clinical measures. Trial registration: This study was registered in the Clinical Trials Protocol Registration and Results System (NCT04237506, January 17, 2020). [ABSTRACT FROM AUTHOR]

Background: Parkinson's disease is characterized by a progressive loss of dopaminergic neurons in the nigrostriatal pathway, leading to dopamine deficiency and motor impairments. Current treatments, such as L-DOPA, provide symptomatic relief but result in off-target effects and diminished efficacy over time. This study explores an alternative approach by investigating the activation of tyrosine hydroxylase, the rate-limiting enzyme in dopamine synthesis. Specifically, we explore the effects of phosphodiesterase (PDE) inhibition and guanylate cyclase-C (GUCY2C) activation on tyrosine hydroxylase Ser40 phosphorylation and their impact on motor behavior in a 6-hydroxydopamine (6-OHDA) Parkinson's disease model. Results: Our findings demonstrate that increasing cyclic nucleotide levels through PDE inhibition and GUCY2C activation significantly enhances tyrosine hydroxylase Ser40 phosphorylation. In a Pitx3-deficient mouse model, which mimics the loss of dopaminergic neurons seen in Parkinson's disease, Ser40 phosphorylation remained manipulable despite reduced tyrosine hydroxylase protein levels. Moreover, we observed no evidence of tyrosine hydroxylase degradation due to Ser40 phosphorylation, challenging previous reports. Furthermore, both PDE inhibition and GUCY2C activation resulted in improved motor behavior in the 6-OHDA Parkinson's disease mouse model, highlighting the potential therapeutic benefits of these approaches. Conclusions: This study underscores the therapeutic potential of enhancing tyrosine hydroxylase Ser40 phosphorylation to improve motor function in Parkinson's disease. Both PDE inhibition and GUCY2C activation represent promising non-invasive strategies to modulate endogenous dopamine biosynthesis and address motor deficits. These findings suggest that targeting cyclic nucleotide pathways could lead to novel therapeutic approaches, either as standalone treatments or in combination with existing therapies like L-DOPA, aiming to provide more durable symptom relief and potentially mitigate neurodegeneration in Parkinson's disease. [ABSTRACT FROM AUTHOR]

Unprovoked seizures in early life are one of the most severe conditions in pediatric neurology, and are often associated with long-lasting cognitive and behavioral deficits, as well as pharmacoresistant epilepsy in adulthood in some conditions. Unillustrated mechanisms greatly restrict the development of preventive strategies for early-life seizures (ELSs) related neuronal impairments. The recent groundbreaking study published in The Journal of Clinical Investigation represents a giant leap forward in understanding the complex pathogenesis mechanism and developing targeted therapies for ELS related neuronal impairments. The authors conducted elegant experiments to locate the activated pyramidal neuron subpopulation in the hippocampus and demonstrated the altered functions of (α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid)-type glutamate receptors (AMPARs). And we believe that the conclusions of this study may assist in further translational efforts to identify preventive targets for neurological disorders associated with early life seizures and propose new avenues for further exploration in this field. [ABSTRACT FROM AUTHOR]

Background: Progressive hearing loss is a common problem in the human population with no effective therapeutics currently available. However, it has a strong genetic contribution, and investigating the genes and regulatory interactions underlying hearing loss offers the possibility of identifying therapeutic candidates. Mutations in regulatory genes are particularly useful for this, and an example is the microRNA miR-96, a post-transcriptional regulator which controls hair cell maturation. Mice and humans carrying mutations in miR-96 all exhibit hearing impairment, in homozygosis if not in heterozygosis, but different mutations result in different physiological, structural and transcriptional phenotypes. Methods: Here we present our characterisation of two lines of mice carrying different human mutations knocked-in to Mir96. We have carried out auditory brainstem response tests to examine their hearing with age and after noise exposure and have used confocal and scanning electron microscopy to examine the ultrastructure of the organ of Corti and hair cell synapses. Bulk RNA-seq was carried out on the organs of Corti of postnatal mice, followed by bioinformatic analyses to identify candidate targets. Results: While mice homozygous for either mutation are profoundly deaf from 2 weeks old, the heterozygous phenotypes differ markedly, with only one mutation resulting in hearing impairment in heterozygosis. Investigations of the structural phenotype showed that one mutation appears to lead to synaptic defects, while the other has a much more severe effect on the hair cell stereociliary bundles. Transcriptome analyses revealed a wide range of misregulated genes in both mutants which were notably dissimilar. We used the transcriptome analyses to investigate candidate therapeutics, and tested one, finding that it delayed the progression of hearing loss in heterozygous mice. Conclusions: Our work adds further support for the importance of the gain of novel targets in microRNA mutants and offers a proof of concept for the identification of pharmacological interventions to maintain hearing. [ABSTRACT FROM AUTHOR]

Background: Coffee and tea consumption account for most caffeine intake and 2–3 billion cups are taken daily around the world. Caffeine dependence is a widespread but under recognized problem. Objectives: To conduct a systematic review on the genetic susceptibility factors affecting caffeine metabolism and caffeine reward and their association with caffeine intake. Methodology: We conducted PubMed and Embase searches using the terms "caffeine", "reward", "gene", "polymorphism", "addiction", "dependence" and "habit" from inception till 2024. The demographics, genetic and clinical data from included studies were extracted and analyzed. Only case-control studies on habitual caffeine drinkers with at least 100 in each arm were included. Results: A total of 2552 studies were screened and 26 studies involving 1,851,428 individuals were included. Several genes that were involved with caffeine metabolism such as CYP1A2, ADORA2A, AHR, POR, ABCG2, CYP2A6, PDSS2 and HECTD4 rs2074356 (A allele specific to East Asians and monomorphic in Europeans, Africans and Americans) were associated with habitual caffeine consumption with effect size difference of 3% to 32% in number of cups of caffeinated drink per day per effect allele. In addition, ALDH2 was linked to the Japanese population. Genes associated with caffeine reward included BDNF, SLC6A4, GCKR, MLXIPL and dopaminergic genes such as DRD2 and DAT1 which had around 2–5% effect size difference in number of cups of caffeinated drink for each allele per day. Conclusion: Several genes that were involved in caffeine metabolism and reward were associated with up to 30% effect size difference in number of cups of caffeinated drink per day, and some associations were specific to certain ethnicities. Identification of at-risk caffeine dependence individuals can lead to early diagnosis and stratification of at-risk vulnerable individuals such as pregnant women and children, and can potentially lead to development of drug targets for dependence to caffeine. [ABSTRACT FROM AUTHOR]

Lewy body dementia (LBD), a class of disorders comprising Parkinson's disease dementia (PDD) and dementia with Lewy bodies (DLB), features substantial clinical and pathological overlap with Alzheimer's disease (AD). The identification of biomarkers unique to LBD pathophysiology could meaningfully advance its diagnosis, monitoring, and treatment. Using quantitative mass spectrometry (MS), we measured over 9,000 proteins across 138 dorsolateral prefrontal cortex (DLPFC) tissues from a University of Pennsylvania autopsy collection comprising control, Parkinson's disease (PD), PDD, and DLB diagnoses. We then analyzed co-expression network protein alterations in those with LBD, validated these disease signatures in two independent LBD datasets, and compared these findings to those observed in network analyses of AD cases. The LBD network revealed numerous groups or "modules" of co-expressed proteins significantly altered in PDD and DLB, representing synaptic, metabolic, and inflammatory pathophysiology. A comparison of validated LBD signatures to those of AD identified distinct differences between the two diseases. Notably, synuclein-associated presynaptic modules were elevated in LBD but decreased in AD relative to controls. We also found that glial-associated matrisome signatures consistently elevated in AD were more variably altered in LBD, ultimately stratifying those LBD cases with low versus high burdens of concurrent beta-amyloid deposition. In conclusion, unbiased network proteomic analysis revealed diverse pathophysiological changes in the LBD frontal cortex distinct from alterations in AD. These results highlight the LBD brain network proteome as a promising source of biomarkers that could enhance clinical recognition and management. [ABSTRACT FROM AUTHOR]

Background: In Alzheimer's disease (AD), the associations between tau pathology and brain atrophy and cognitive decline are well established, but imperfect. We investigate whether cerebrospinal fluid (CSF) biomarkers of biological processes (vascular, synaptic, and axonal integrity, neuroinflammation, neurotrophic factors) explain the disconnection between tau pathology and brain atrophy (brain resilience), and tau pathology and cognitive decline (cognitive resilience). Methods: We included 428 amyloid positive participants (134 cognitively unimpaired (CU), 128 with mild cognitive impairment (MCI), 166 with AD dementia) from the BioFINDER-2 study. At baseline, participants underwent tau positron emission tomography (tau-PET), magnetic resonance imaging (MRI), cognitive testing, and lumbar puncture. Longitudinal data were available for MRI (mean (standard deviation) follow-up 26.4 (10.7) months) and cognition (25.2 (11.4) months). We analysed 18 pre-selected CSF proteins, reflecting vascular, synaptic, and axonal integrity, neuroinflammation, and neurotrophic factors. Stratifying by cognitive status, we performed linear mixed-effects models with cortical thickness (brain resilience) and global cognition (cognitive resilience) as dependent variables to assess whether the CSF biomarkers interacted with tau-PET levels in its effect on cortical atrophy and cognitive decline. Results: Regarding brain resilience, interaction effects were observed in AD dementia, with vascular integrity biomarkers (VEGF-A (βinteraction = -0.009, pFDR = 0.047) and VEGF-B (βinteraction = -0.010, pFDR = 0.037)) negatively moderating the association between tau-PET signal and atrophy. In MCI, higher NfL levels were associated with more longitudinal cortical atrophy (β = -0.109, pFDR = 0.033) and lower baseline cortical thickness (β = -0.708, pFDR = 0.033) controlling for tau-PET signal. Cognitive resilience analyses in CU revealed interactions with tau-PET signal for inflammatory (GFAP, IL-15; βinteraction -0.073–-0.069, pFDR 0.001–0.045), vascular (VEGF-A, VEGF-D, PGF; βinteraction -0.099–-0.063, pFDR < 0.001–0.046), synaptic (14–3-3ζ/δ; βinteraction = -0.092, pFDR = 0.041), axonal (NfL; βinteraction = -0.079, pFDR < 0.001), and neurotrophic (NGF; βinteraction = 0.091, pFDR < 0.001) biomarkers. In MCI higher NfL levels (βmain = -0.690, pFDR = 0.025) were associated with faster cognitive decline independent of tau-PET signal. Conclusions: Biomarkers of co-existing pathological processes, in particular vascular pathology and axonal degeneration, interact with levels of tau pathology on its association with the downstream effects of AD pathology (i.e. brain atrophy and cognitive decline). This indicates that vascular pathology and axonal degeneration could impact brain and cognitive resilience. [ABSTRACT FROM AUTHOR]

Background: Defective mitochondria and aberrant brain mitochondrial bioenergetics are consistent features in syndromic intellectual disability disorders, such as Rett syndrome (RTT), a rare neurologic disorder that severely affects mainly females carrying mutations in the X-linked MECP2 gene. A pool of CB1 cannabinoid receptors (CB1R), the primary receptor subtype of the endocannabinoid system in the brain, is located on brain mitochondrial membranes (mtCB1R), where it can locally regulate energy production, synaptic transmission and memory abilities through the inhibition of the intra-mitochondrial protein kinase A (mtPKA). In the present study, we asked whether an overactive mtCB1R-mtPKA signaling might underlie the brain mitochondrial alterations in RTT and whether its modulation by systemic administration of the CB1R inverse agonist rimonabant might improve bioenergetics and cognitive defects in mice modeling RTT. Methods: Rimonabant (0.3 mg/kg/day, intraperitoneal injections) was administered daily to symptomatic female mice carrying a truncating mutation of the Mecp2 gene and its effects on brain mitochondria functionality, systemic oxidative status, and memory function were assessed. Results: mtCB1R is overexpressed in the RTT mouse brain. Subchronic treatment with rimonabant normalizes mtCB1R expression in RTT mouse brains, boosts mtPKA signaling, and restores the defective brain mitochondrial bioenergetics, abnormal peripheral redox homeostasis, and impaired cognitive abilities in RTT mice. Limitations: The lack of selectivity of the rimonabant treatment towards mtCB1R does not allow us to exclude that the beneficial effects exerted by the treatment in the RTT mouse model may be ascribed more broadly to the modulation of CB1R activity and distribution among intracellular compartments, rather than to a selective effect on mtCB1R-mediated signaling. The low sample size of few experiments is a further limitation that has been addressed replicating the main findings under different experimental conditions. Conclusions: The present data identify mtCB1R overexpression as a novel molecular alteration in the RTT mouse brain that may underlie defective brain mitochondrial bioenergetics and cognitive dysfunction. [ABSTRACT FROM AUTHOR]

A hexanucleotide repeat expansion (HRE) in C9ORF72 is the most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Human brain imaging and experimental studies indicate early changes in brain structure and connectivity in C9-ALS/FTD, even before symptom onset. Because these early disease phenotypes remain incompletely understood, we generated iPSC-derived cerebral organoid models from C9-ALS/FTD patients, presymptomatic C9ORF72-HRE (C9-HRE) carriers, and controls. Our work revealed the presence of all three C9-HRE-related molecular pathologies and developmental stage-dependent size phenotypes in cerebral organoids from C9-ALS/FTD patients. In addition, single-cell RNA sequencing identified changes in cell type abundance and distribution in C9-ALS/FTD organoids, including a reduction in the number of deep layer cortical neurons and the distribution of neural progenitors. Further, molecular and cellular analyses and patch-clamp electrophysiology detected various changes in synapse structure and function. Intriguingly, organoids from all presymptomatic C9-HRE carriers displayed C9-HRE molecular pathology, whereas the extent to which more downstream cellular defects, as found in C9-ALS/FTD models, were detected varied for the different presymptomatic C9-HRE cases. Together, these results unveil early changes in 3D human brain tissue organization and synaptic connectivity in C9-ALS/FTD that likely constitute initial pathologies crucial for understanding disease onset and the design of therapeutic strategies. [ABSTRACT FROM AUTHOR]

The identification of acute cardioprotective strategies against myocardial ischemia/reperfusion (I/R) injury that can be applied in the catheterization room is currently an unmet clinical need and several interventions evaluated in the past at the pre-clinical level have failed in translation. Autonomic imbalance, sustained by an abnormal afferent signalling, is a key component of I/R injury. Accordingly, there is a strong rationale for neuromodulation strategies, aimed at reducing sympathetic activity and/or increasing vagal tone, in this setting. In this review we focus on cervical vagal nerve stimulation (cVNS) and on transcutaneous auricular vagus nerve stimulation (taVNS); the latest has the potential to overcome several of the issues of invasive cVNS, including the possibility of being used in an acute setting, while retaining its beneficial effects. First, we discuss the pathophysiology of I/R injury, that is mostly a consequence of the overproduction of reactive oxygen species. Second, we describe the functional anatomy of the parasympathetic branch of the autonomic nervous system and the most relevant principles of bioelectronic medicine applied to electrical vagal modulation, with a particular focus on taVNS. Then, we provide a detailed and comprehensive summary of the most relevant pre-clinical studies of invasive and non-invasive VNS that support its strong cardioprotective effect whenever there is an acute or chronic cardiac injury and specifically in the setting of myocardial I/R injury. The potential benefit in the emerging field of post cardiac arrest syndrome (PCAS) is also mentioned. Indeed, electrical cVNS has a strong anti-adrenergic, anti-inflammatory, antioxidants, anti-apoptotic and pro-angiogenic effect; most of the involved molecular pathways were already directly confirmed to take place at the cardiac level for taVNS. Pre-clinical data clearly show that the sooner VNS is applied, the better the outcome, with the possibility of a marked infarct size reduction and almost complete left ventricular reverse remodelling when VNS is applied immediately before and during reperfusion. Finally, we describe in detail the limited but very promising clinical experience of taVNS in I/R injury available so far. [ABSTRACT FROM AUTHOR]

Rationale: Central neuropathic pain resulting from spinal cord injury is notoriously debilitating and difficult to treat with few currently available treatments. A novel molecule with intrathecal administration: Ziconotide has been approved for treatment of refractory neuropathic pain in general. It acts as a presynaptic calcium channel blocker. A pilot study has shown its potential in SCI neuropathic pain patients. Objective: The aim of this study is to determine the long-term (6 months) efficacy of chronic intrathecal ziconotide for the treatment of neuropathic SCI pain. Study design: Multicenter, Randomized, Comparative, Placebo controlled, Double blind clinical trial, with a crossover of random alternated periods of 6 months (placebo or ITZ) for a total of 15 months including a total of 44 patients. Study population: • Patients with SCI of various etiologies exhibiting neuropathic pain refractory to non-invasive treatments. • > 18 years. Intervention: Intrathecal administration of ziconotide via an implanted pump. Study outcomes: Primary study outcome Difference in pain intensity for all patients between effective treatment and placebo periods. Secondary study outcomes 1. Continuous evaluation of pain intensity. 2. Percentage of patients with at least 30% of pain reduction. 3. Satisfaction level of the patient pain relief. 4. Declarations of serious adverse events. 5. Duration and intensity of spontaneous and provoked pain. 6. Quality of life. 7. Patient global impression of change. 8. Quantification of daily dosages of analgesic drug intake. 9. Long term memory and neurocognitive effects. 10. Assessment of the patient's physical and emotional distress. Nature and extent of the burden and risks associated with participation, benefit, and group relatedness: Participation in this study is in accordance with current treatment protocols for SCI neuropathic pain in France therefore it proposes a treatment that would currently be considered regular practice even though no RCT evidence is yet available. The study gives patients the advantage of directly testing versus placebo a treatment that otherwise entails significant constraints. A Data Safety Monitoring board (DSMB) will be created for continuous safety analysis. Furthermore, patients will be followed in specialized pain centers offering the possibility of continuing their treatment after the study period. [ABSTRACT FROM AUTHOR]

Gamma-aminobutyric acid (GABA), the most important inhibitory neurotransmitter in the human brain, has long been considered essential in human behavior in general and learning in particular. GABA concentration can be quantified using magnetic resonance spectroscopy (MRS). Using this technique, numerous studies have reported associations between baseline GABA levels and various human behaviors. However, regional GABA concentration is not fixed and may exhibit rapid modulation as a function of environmental factors. Hence, quantification of GABA levels at several time points during the performance of tasks can provide insights into the dynamics of GABA levels in distinct brain regions. This review reports on findings from studies using repeated measures (n = 41) examining the dynamic modulation of GABA levels in humans in response to various interventions in the perceptual, motor, and cognitive domains to explore associations between GABA modulation and human behavior. GABA levels in a specific brain area may increase or decrease during task performance or as a function of learning, depending on its precise involvement in the process under investigation. Here, we summarize the available evidence and derive two overarching hypotheses regarding the role of GABA modulation in performance and learning. Firstly, training-induced increases in GABA levels appear to be associated with an improved ability to differentiate minor perceptual differences during perceptual learning. This observation gives rise to the 'GABA increase for better neural distinctiveness hypothesis'. Secondly, converging evidence suggests that reducing GABA levels may play a beneficial role in effectively filtering perceptual noise, enhancing motor learning, and improving performance in visuomotor tasks. Additionally, some studies suggest that the reduction of GABA levels is related to better working memory and successful reinforcement learning. These observations inspire the 'GABA decrease to boost learning hypothesis', which states that decreasing neural inhibition through a reduction of GABA in dedicated brain areas facilitates human learning. Additionally, modulation of GABA levels is also observed after short-term physical exercise. Future work should elucidate which specific circumstances induce robust GABA modulation to enhance neuroplasticity and boost performance. [ABSTRACT FROM AUTHOR]

Background: Delirium and Alzheimer's disease (AD) are common causes of cognitive dysfunction among older adults. These neurodegenerative diseases share a common and complex relationship, and can occur individually or concurrently, increasing the chance of permanent mental dysfunction. However, the common molecular pathophysiology, key proteomic biomarkers, and functional pathways are largely unknown, whereby delirium is superimposed on AD and dementia. Methods: We employed an integrated bioinformatics and system biology analysis approach to decipher such common key proteomic signatures, pathophysiological links between delirium and AD by analyzing the gene expression data of AD-affected human brain samples and comparing them with delirium-associated proteins. The present study identified the common drug target hub-proteins examining the protein–protein interaction (PPI) and gene regulatory network analysis. The functional enrichment and pathway analysis was conducted to reveal the common pathophysiological relationship. Finally, the molecular docking and dynamic simulation was used to computationally identify and validate the potential drug target and repurposable drugs for delirium and AD. Results: We detected 99 shared differentially expressed genes (sDEGs) associated with AD and delirium. The sDEGs-set enrichment analysis detected the transmission across chemical synapses, neurodegeneration pathways, neuroinflammation and glutamatergic signaling pathway, oxidative stress, and BDNF signaling pathway as the most significant signaling pathways shared by delirium and AD. The disease-sDEGs interaction analysis highlighted the other disease risk factors with delirium and AD development and progression. Among the sDEGs of delirium and AD, the top 10 hub-proteins including ALB, APP, BDNF, CREB1, DLG4, GAD1, GAD2, GFAP, GRIN2B and GRIN2A were found by the PPI network analysis. Based on the maximum molecular docking binding affinities and molecular dynamic simulation (100 ns) results, the ALB and GAD2 were found as prominent drug target proteins when tacrine and donepezil were identified as potential drug candidates for delirium and AD. Conclusion: The study outlined the common key biomolecules and biological pathways shared by delirium and AD. The computationally reported potential drug molecules need a deeper investigation including clinical trials to validate their effectiveness. The outcomes from this study will help to understand the typical pathophysiological relationship between delirium and AD and flag future therapeutic development research for delirium. [ABSTRACT FROM AUTHOR]

Palmitoylation is a type of lipid modification that plays an important role in various aspects of neuronal function. Over the past few decades, several studies have shown that the palmitoylation of synaptic proteins is involved in neurotransmission and synaptic functions. Palmitoyl acyltransferases (PATs), which belong to the DHHC family, are major players in the regulation of palmitoylation. Dysregulated palmitoylation of synaptic proteins and mutated/dysregulated DHHC proteins are associated with several neurodegenerative diseases, such as Alzheimer's disease (AD), Huntington's disease (HD), and Parkinson's disease (PD). In this review, we summarize the recent discoveries on the subcellular distribution of DHHC proteins and analyze their expression patterns in different brain cells. In particular, this review discusses how palmitoylation of synaptic proteins regulates synaptic vesicle exocytotic fusion and the localization, clustering, and transport of several postsynaptic receptors, as well as the role of palmitoylation of other proteins in regulating synaptic proteins. Additionally, some of the specific known associations of these factors with neurodegenerative disorders are explored, with a few suggestions for the development of therapeutic strategies. Finally, this review provides possible directions for future research to reveal detailed and specific mechanisms underlying the roles of synaptic protein palmitoylation. [ABSTRACT FROM AUTHOR]

Background: Local translation at synapses is important for rapidly remodeling the synaptic proteome to sustain long-term plasticity and memory. While the regulatory mechanisms underlying memory-associated local translation have been widely elucidated in the postsynaptic/dendritic region, there is no direct evidence for which RNA-binding protein (RBP) in axons controls target-specific mRNA translation to promote long-term potentiation (LTP) and memory. We previously reported that translation controlled by cytoplasmic polyadenylation element binding protein 2 (CPEB2) is important for postsynaptic plasticity and memory. Here, we investigated whether CPEB2 regulates axonal translation to support presynaptic plasticity. Methods: Behavioral and electrophysiological assessments were conducted in mice with pan neuron/glia- or glutamatergic neuron-specific knockout of CPEB2. Hippocampal Schaffer collateral (SC)-CA1 and temporoammonic (TA)-CA1 pathways were electro-recorded to monitor synaptic transmission and LTP evoked by 4 trains of high-frequency stimulation. RNA immunoprecipitation, coupled with bioinformatics analysis, were used to unveil CPEB2-binding axonal RNA candidates associated with learning, which were further validated by Western blotting and luciferase reporter assays. Adeno-associated viruses expressing Cre recombinase were stereotaxically delivered to the pre- or post-synaptic region of the TA circuit to ablate Cpeb2 for further electrophysiological investigation. Biochemically isolated synaptosomes and axotomized neurons cultured on a microfluidic platform were applied to measure axonal protein synthesis and FM4-64FX-loaded synaptic vesicles. Results: Electrophysiological analysis of hippocampal CA1 neurons detected abnormal excitability and vesicle release probability in CPEB2-depleted SC and TA afferents, so we cross-compared the CPEB2-immunoprecipitated transcriptome with a learning-induced axonal translatome in the adult cortex to identify axonal targets possibly regulated by CPEB2. We validated that Slc17a6, encoding vesicular glutamate transporter 2 (VGLUT2), is translationally upregulated by CPEB2. Conditional knockout of CPEB2 in VGLUT2-expressing glutamatergic neurons impaired consolidation of hippocampus-dependent memory in mice. Presynaptic-specific ablation of Cpeb2 in VGLUT2-dominated TA afferents was sufficient to attenuate protein synthesis-dependent LTP. Moreover, blocking activity-induced axonal Slc17a6 translation by CPEB2 deficiency or cycloheximide diminished the releasable pool of VGLUT2-containing synaptic vesicles. Conclusions: We identified 272 CPEB2-binding transcripts with altered axonal translation post-learning and established a causal link between CPEB2-driven axonal synthesis of VGLUT2 and presynaptic translation-dependent LTP. These findings extend our understanding of memory-related translational control mechanisms in the presynaptic compartment. [ABSTRACT FROM AUTHOR]