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Frame-shifted amyloid precursor protein (APP+1), which has a truncated out-of-frame C-terminus, accumulates in the neuropathological hallmarks of patients with Alzheimer's disease pathology. To study a possible involvement of APP+1 in the pathogenesis of Alzheimer's disease, we expressed APP695 and APP+1 in the HEK293 cell-line and studied whether the processing of APP695 was affected. APP+1 is a secretory protein, but high expression of APP695 and APP+1 results in the formation of intracellular aggregate-like structures containing both proteins and Fe65, an adaptor protein that interacts with APP695. APP+1 is shown to interact with APP695, suggesting that these structures consist of functional protein complexes. Such an interaction can also be anticipated in post-mortem brains of young Down's syndrome patients without any sign of neuropathology. Here we observed APP+1 immunoreactivity in beaded fibres. Additional support for functional consequences on the processing of APP695 comes from a 1.4-fold increase in levels of secreted amyloid β40 in cells co-expressing APP695 and APP+1, although APP+1 itself does not contain the amyloid β sequence. Taken together, these data show that co-expression of APP695 and APP+1 affects the processing of APP695 in a pro-amyloidogenic way and this could gradually contribute to Alzheimer's disease pathology, as has been implicated in Down's syndrome patients. [ABSTRACT FROM AUTHOR]

The development of immune cell engagers (ICEs) can be limited by logistical and functional restrictions associated with fusion protein designs, thus limiting immune cell recruitment to solid tumors. Herein, a high affinity superantigen‐based multivalent ICE is developed for simultaneous activation and recruitment of NK and T cells for tumor treatment. Yeast library‐based directed evolution is adopted to identify superantigen variants possessing enhanced binding affinity to immunoreceptors expressed on human T cells and NK cells. High‐affinity superantigens exhibiting improved immune‐stimulatory activities are then incorporated into a superantigen‐based tri‐functional yeast‐display‐enhanced multivalent immune cell engager (STYMIE), which is functionalized with a nanobody, a Neo‐2/15 cytokine, and an Fc domain for tumor targeting, immune stimulation, and prolonged circulation, respectively. Intravenous administration of STYMIE enhances NK and T cell recruitment into solid tumors, leading to enhanced inhibition in multiple tumor models. The study offers design principles for multifunctional ICEs. [ABSTRACT FROM AUTHOR]

Rhythmic inspiratory activity is generated in the preBötzinger complex (preBötC), a neuronal network located bilaterally in the ventrolateral medulla. Cholinergic neurotransmission affects respiratory rhythmogenic neurons and inhibitory glycinergic neurons in the preBötC. Acetylcholine has been extensively investigated given that cholinergic fibers and receptors are present and functional in the preBötC, are important in sleep/wake cycling, and modulate inspiratory frequency through its action on preBötC neurons. Despite its role in modulating inspiratory rhythm, the source of acetylcholine input to the preBötC is not known. In the present study, we used retrograde and anterograde viral tracing approaches in transgenic mice expressing Cre‐recombinase driven by the choline acetyltransferase promoter to identify the source of cholinergic inputs to the preBötC. Surprisingly, we observed very few, if any, cholinergic projections originating from the laterodorsal and pedunculopontine tegmental nuclei (LDT/PPT), two main cholinergic, state‐dependent systems long hypothesized as the main source of cholinergic inputs to the preBötC. On the contrary, we identified glutamatergic and GABAergic/glycinergic neurons in the PPT/LDT that send projections to the preBötC. Although these neurons contribute minimally to the direct cholinergic modulation of preBötC neurons, they could be involved in state‐dependent regulation of breathing. Our data also suggest that the source of cholinergic inputs to the preBötC appears to originate from cholinergic neurons in neighboring regions of the medulla, the intermediate reticular formation, the lateral paragigantocellularis, and the nucleus of the solitary tract. [ABSTRACT FROM AUTHOR]

The brain relies on many forms of dynamic activities in individual neurons, from synaptic transmission to electrical activity and intracellular signaling events. Monitoring these neuronal activities with high spatiotemporal resolution in the context of animal behavior is a necessary step to achieve a mechanistic understanding of brain function. With the rapid development and dissemination of highly optimized genetically encoded fluorescent sensors, a growing number of brain activities can now be visualized in vivo. To date, cellular calcium imaging, which has been largely used as a proxy for electrical activity, has become a mainstay in systems neuroscience. While challenges remain, voltage imaging of neural populations is now possible. In addition, it is becoming increasingly practical to image over half a dozen neurotransmitters, as well as certain intracellular signaling and metabolic activities. These new capabilities enable neuroscientists to test previously unattainable hypotheses and questions. This review summarizes recent progress in the development and delivery of genetically encoded fluorescent sensors, and highlights example applications in the context of in vivo imaging. [ABSTRACT FROM AUTHOR]

The formation of extracellular vesicles (EVs) is induced by the sphingolipid ceramide. How this pathway is regulated is not entirely understood. Here, we report that the ceramide transport protein (CERT) mediates a non‐vesicular transport of ceramide between the endoplasmic reticulum (ER) and the multivesicular endosome at contact sites. The process depends on the interaction of CERT's PH domain with PI4P generated by PI4KIIα at endosomes. Furthermore, a complex is formed between the START domain of CERT, which carries ceramide, and the Tsg101 protein, which is part of the endosomal sorting complex required for transport (ESCRT‐I). Inhibition of ceramide biosynthesis reduces CERT‐Tsg101 complex formation. Overexpression of CERT increases EV secretion while its inhibition reduces EV formation and the concentration of ceramides and sphingomyelins in EVs. In conclusion, we discovered a function of CERT in regulating the sphingolipid composition and biogenesis of EVs, which links ceramide to the ESCRT‐dependent pathway. [ABSTRACT FROM AUTHOR]

The gut microbiota coevolves with its host, and numerous factors like diet, lifestyle, drug intake and geographical location continuously modify its composition, deeply influencing host health. Recent studies demonstrated that gut dysbiosis can alter normal brain function through the so‐called gut–brain axis, a bidirectional communication network between the central nervous system and the gastrointestinal tract, thus playing a key role in the pathogenesis of neurodegenerative disorders, such as Alzheimer's disease (AD). In this perspective, in the constant search for novel treatments in AD, the rational modulation of gut microbiota composition could represent a promising approach to prevent or delay AD onset or to counteract its progression. Preclinical and human studies on microbiota modulation through oral bacteriotherapy and faecal transplantation showed anti‐inflammatory and antioxidant effects, upregulation of plasma concentration of neuroprotective hormones, restoration of impaired proteolytic pathways, amelioration of energy homeostasis with consequent decrease of AD molecular hallmarks and improvement of behavioural and cognitive performances. In this review, we dissect the role of gut microbiota in AD and highlight recent advances in the development of new multitarget strategies for microbiota modulation to be used as possible preventative and therapeutic approaches in AD. [ABSTRACT FROM AUTHOR]

Hypothalamic neurons expressing gonadotropin‐releasing hormone (GnRH), the "master molecule" regulating reproduction and fertility, migrate from their birthplace in the nose to their destination using a system of guidance cues, which include the semaphorins and their receptors, the neuropilins and plexins, among others. Here, we show that selectively deleting neuropilin‐1 in new GnRH neurons enhances their survival and migration, resulting in excess neurons in the hypothalamus and in their unusual accumulation in the accessory olfactory bulb, as well as an acceleration of mature patterns of activity. In female mice, these alterations result in early prepubertal weight gain, premature attraction to male odors, and precocious puberty. Our findings suggest that rather than being influenced by peripheral energy state, GnRH neurons themselves, through neuropilin–semaphorin signaling, might engineer the timing of puberty by regulating peripheral adiposity and behavioral switches, thus acting as a bridge between the reproductive and metabolic axes. Synopsis: By regulating GnRH neuronal survival, migration and activity, the expression of Neuropilin 1 in GnRH neurons regulates sexual attraction, prepubertal weight gain and the timing of puberty. Nrp1 expression in GnRH neurons controls their number and distribution during embryogenesis.The lack of Nrp1 expression in GnRH neurons triggers early sexual behavior.GnRH neurons are directly involved in prepubertal weight gain.Disrupting Nrp1 signaling in GnRH neurons leads to central precocious puberty. [ABSTRACT FROM AUTHOR]

Machado--Joseph disease (MJD), also known as spinocerebellar ataxia type 3 (SCA3), is an incurable disorder, widely regarded as the most common form of spinocerebellar ataxia in the world. MJD/SCA3 arises from mutation of the ATXN3 gene, but this simple monogenic cause contrasts with the complexity of the pathogenic mechanisms that are currently admitted to underlie neuronal dysfunction and death. The aberrantly expanded protein product -- ataxin-3 -- is known to aggregate and generate toxic species that disrupt several cell systems, including autophagy, proteostasis, transcription, mitochondrial function and signalling. Over the years, research into putative therapeutic approaches has often been devoted to the development of strategies that counteract disease at different stages of cellular pathogenesis. Silencing the pathogenic protein, blocking aggregation, inhibiting toxic proteolytic processing and counteracting dysfunctions of the cellular systems affected have yielded promising ameliorating results in studies with cellular and animal models. The current review analyses the available studies dedicated to the investigation of MJD/SCA3 pathogenesis and the exploration of possible therapeutic strategies, focusing primarily on gene therapy and pharmacological approaches rooted on the molecular and cellular mechanisms of disease. [ABSTRACT FROM AUTHOR]

ABSTRACT The relationship between atmospheric circulation and climate in Svalbard has been described in dozens of studies. However, the data used for that purpose usually came from permanent stations on the coast. The influence of atmospheric circulation on topoclimatic diversity has not been explored so often, and hardly at all for other periods than the Arctic summer. In this article, the relationships between circulation and air temperature are described using daily data sourced from six sites located around Forlandsundet ( NW Spitsbergen) during 2010-2013. The analysis was conducted independently for three seasons identified as: winter (Nov-Mar), spring/autumn (Apr-May and Sep-Oct) and summer (Jun-Aug) and also for three air temperature parameters: diurnal mean (Ti), maximum (Tmax) and minimum (Tmin) temperature. The atmospheric circulation in the studied area was described using Tadeusz Niedźwiedź's classification of diurnal circulation types for Svalbard. The influence of atmospheric circulation on the spatial pattern of air temperature is not uniform across the Forlandsundet region; in particular, important differences were observed between coastal and inland parts of the study area. Thus, generalization of relationships between air temperature and atmospheric circulation for the entire area of Spitsbergen based on data only from coastal stations is not appropriate. The influence of atmospheric circulation on the spatial pattern of air temperature in the Forlandsundet region also changes through the year. In the cold season (Sep-May) it differs significantly from that observed in summer (Jun-Aug), and this feature is also seen in analyses of the 10% highest (≥ 90th percentile) and lowest (≤ 10th percentile) thermal differences. In summer, the influence of atmospheric circulation on air temperature in the topoclimatic scale is definitely less stable than in the cold season. [ABSTRACT FROM AUTHOR]

Congenital hypogonadotropic hypogonadism ( CHH) is a rare genetic form of isolated gonadotropin-releasing hormone (Gn RH) deficiency caused by mutations in > 30 genes. Fibroblast growth factor receptor 1 ( FGFR1) is the most frequently mutated gene in CHH and is implicated in Gn RH neuron development and maintenance. We note that a CHH FGFR1 mutation (p.L342S) decreases signaling of the metabolic regulator FGF21 by impairing the association of FGFR1 with β-Klotho ( KLB), the obligate co-receptor for FGF21. We thus hypothesized that the metabolic FGF21/ KLB/ FGFR1 pathway is involved in CHH. Genetic screening of 334 CHH patients identified seven heterozygous loss-of-function KLB mutations in 13 patients (4%). Most patients with KLB mutations (9/13) exhibited metabolic defects. In mice, lack of Klb led to delayed puberty, altered estrous cyclicity, and subfertility due to a hypothalamic defect associated with inability of Gn RH neurons to release Gn RH in response to FGF21. Peripheral FGF21 administration could indeed reach Gn RH neurons through circumventricular organs in the hypothalamus. We conclude that FGF21/ KLB/ FGFR1 signaling plays an essential role in Gn RH biology, potentially linking metabolism with reproduction. [ABSTRACT FROM AUTHOR]

Tumor progression alters the composition and physical properties of the extracellular matrix. Particularly, increased matrix stiffness has profound effects on tumor growth and metastasis. While endothelial cells are key players in cancer progression, the influence of tumor stiffness on the endothelium and the impact on metastasis is unknown. Through quantitative mass spectrometry, we find that the matricellular protein CCN1/ CYR61 is highly regulated by stiffness in endothelial cells. We show that stiffness-induced CCN1 activates β-catenin nuclear translocation and signaling and that this contributes to upregulate N-cadherin levels on the surface of the endothelium, in vitro. This facilitates N-cadherin-dependent cancer cell-endothelium interaction. Using intravital imaging, we show that knockout of Ccn1 in endothelial cells inhibits melanoma cancer cell binding to the blood vessels, a critical step in cancer cell transit through the vasculature to metastasize. Targeting stiffness-induced changes in the vasculature, such as CCN1, is therefore a potential yet unappreciated mechanism to impair metastasis. [ABSTRACT FROM AUTHOR]

The ubiquitin mutant UBB+1 has been identified as a hallmark of neurodegenerative diseases. In this study, we characterize polyubiquitinated forms of UBB+1 in vitro and from patient samples. The ability of UBB+1 to be readily ubiquitinated by several E2 enzymes provided a mechanism for the controlled synthesis and purification of defined conjugates. This allowed us to utilize polyUb- UBB+1 conjugates for biochemical assays, as well as solution NMR. Coupled with our immunoassay for detection of ubiquitinated forms of UBB+1 in patient blood samples, we gain a clearer picture of the molecular mechanisms underlying neurodegenerative diseases. [ABSTRACT FROM AUTHOR]

Alzheimer's disease ( AD) is the most common neurodegenerative disease and is characterized by accumulation of misfolded and aggregated proteins. Since the ubiquitin-proteasome system ( UPS) is the major intracellular protein quality control ( PQC) system in eukaryotic cells, it is likely involved in the etiology of AD. The frameshift form of ubiquitin (Ubb+1) accumulates in the neuritic plaques and neurofibrillary tangles in patients with AD. Ubb+1 accumulates in an age-dependent manner as a result of RNA-polymerase mediated molecular misreading during transcription, which allows the formation of mutant proteins in the absence of gene mutations. The accumulation of the Ubb+1 protein may act as an endogenous reporter for proteasome dysfunction and a growing number of studies have shown that Ubb+1 may play more important pathogenic roles in AD etiology than previously hypothesized. The yeast Saccharomyces cerevisiae shares many conserved biological processes with all eukaryotic cells, including human neurons. This organism has been regarded as a model system for investigating the fundamental intracellular mechanisms, including those underlying neurodegeneration. We propose here that yeast systems biology approaches, combined with cell and molecular biology approaches will increase the relevant knowledge needed for advancement and elucidation of mechanisms and complex traits, which could provide new targets for therapeutic intervention in AD. WIREs Syst Biol Med 2016, 8:300-313. doi: 10.1002/wsbm.1340 For further resources related to this article, please visit the . [ABSTRACT FROM AUTHOR]

Aims Polyglutamine ( polyQ) diseases are characterized by the expansion of a polymorphic glutamine sequence in disease-specific proteins and exhibit aggregation of these proteins. This is combated by the cellular protein quality control ( PQC) system, consisting of chaperone-mediated refolding as well as proteasomal and lysosomal degradation pathways. Our recent study in the polyQ disease spinocerebellar ataxia type 3 ( SCA3) suggested a distinct pattern of protein aggregation and PQC dysregulation. Methods To corroborate these findings we have investigated immunohistochemically stained 5 μm sections from different brain areas of Huntington's disease ( HD) and SCA3 patients. Results Irrespective of disease and brain region, we observed peri- and intranuclear polyQ protein aggregates. A subset of neurones with intranuclear inclusions bodies exhibited signs of proteasomal dysfunction, up-regulation of HSPA1A and re-distribution of DNAJB1. The extent of the observed effects varied depending on brain area and disease protein. Conclusions Our results suggest a common sequence, in which formation of cytoplasmic and nuclear inclusions precede proteasomal impairment and induction of the cellular stress response. Clearly, impairment of the PQC is not the primary cause for inclusion formation, but rather a consequence that might contribute to neuronal dysfunction and death. Notably, the inclusion pathology is not directly correlated to the severity of the degeneration in different areas, implying that different populations of neurones respond to polyQ aggregation with varying efficacy and that protein aggregation outside the neuronal perikaryon (e.g. axonal aggregates) or other effects of polyQ aggregation, which are more difficult to visualize, may contribute to neurodegeneration. [ABSTRACT FROM AUTHOR]

Mitral and tufted cells are the projection neurons of the olfactory bulb ( OB). We previously reported that somata location and innervation patterns were different between early- and late-born mitral cells (Imamura et al., 2011). Here, we introduced a plasmid that drives the expression of a GFP gene into the mouse OB using in utero electroporation, and demonstrated that we can deliver the plasmid vectors into distinct subsets of OB projection neurons by changing the timing of electroporation after fertilisation. The electroporation performed at embryonic day (E)10 preferentially labeled mitral cells in the accessory OB and main OB mitral cells in dorsomedial mitral cell layer ( MCL). In contrast, the E12 electroporation introduced the plasmid vectors preferentially into main OB mitral cells in the ventrolateral MCL and tufted cells. Combining these data with BrdU injections, we confirmed that E10 and E12 electroporation preferentially labeled early- and late-born projection neurons, respectively. This work introduces a novel method for segregated labeling of mouse olfactory bulb projection neurons based on their birthdates. With this technique we found that early- and late-born projection neurons extend their secondary dendrites in the deep and superficial external plexiform layer ( EPL), respectively. Although a similar segregation has been suggested for mitral vs. tufted cell dendrites, we found mitral cells projecting secondary dendrites into the superficial EPL in E12-electroporated main OB. Our observations indicate that timing of neurogenesis regulates not only somata location and innervation patterns but also the laminar organisation of projection neuron dendrites in the EPL. [ABSTRACT FROM AUTHOR]

Spinocerebellar ataxia type 2 ( SCA2) is a hereditary neurodegenerative disorder caused by the expansion of the trinucleotide CAG repeats encoding elongated polyglutamine tract in ataxin-2, the SCA2 gene product. Polyglutamine diseases comprise nine genetic entities, including seven different forms of spinocerebellar ataxias, Huntington's disease, and spinal and bulbar muscular atrophy. These are pathologically characterized by neuronal loss and intranuclear aggregates or inclusions of mutant proteins including expanded polyglutamine in selected neuronal groups. Previously, we examined immunolocalization of ubiquitin, expanded polyglutamine (probed by 1 C2 antibody), and ataxin-2 in genetically confirmed SCA2 patients. In the present study, we expanded this approach by distinguishing different patterns of subcellular 1 C2 immunoreactivity ('granular cytoplasmic,' 'cytoplasmic and nuclear' and 'nuclear with inclusions.') and by quantifying their regional frequencies in three autopsied SCA2 brains at different stage of the disease. Comparison with neuronal loss and gliosis revealed that overall 1 C2 immunoreactivity was paralleled with their severity. Furthermore, appearance of granular cytoplasmic pattern corresponded to early stage, cytoplasmic and nuclear pattern to active stage, and nuclear with inclusions pattern to final stage. We conclude that this 1 C2-immunoreactive typing may be useful for evaluating the overall severity and extent of affected regions and estimating the neuropathological stage of SCA2. [ABSTRACT FROM AUTHOR]

K. Seidel, M. Meister, G. J. Dugbartey, M. P. Zijlstra, J. Vinet, E. R. P. Brunt, F. W. van Leeuwen, U. Rüb, H. H. Kampinga and W. F. A. den Dunnen (2012) Neuropathology and Applied Neurobiology 38, 548-558 Cellular protein quality control and the evolution of aggregates in spinocerebellar ataxia type 3 (SCA3) Aims: A characteristic of polyglutamine diseases is the increased propensity of disease proteins to aggregate, which is thought to be a major contributing factor to the underlying neurodegeneration. Healthy cells contain mechanisms for handling protein damage, the protein quality control, which must be impaired or inefficient to permit proteotoxicity under pathological conditions. Methods: We used a quantitative analysis of immunohistochemistry of the pons of eight patients with the polyglutamine disorder spinocerebellar ataxia type 3. We employed the anti-polyglutamine antibody 1C2, antibodies against p62 that is involved in delivering ubiquitinated protein aggregates to autophagosomes, antibodies against the chaperones HSPA1A and DNAJB1 and the proteasomal stress marker UBB+1. Results: The 1C2 antibody stained neuronal nuclear inclusions (NNIs), diffuse nuclear staining (DNS), granular cytoplasmic staining (GCS) and combinations, with reproducible distribution. P62 always co-localized with 1C2 in NNI. DNS and GCS co-stained with a lower frequency. UBB+1 was present in a subset of neurones with NNI. A subset of UBB+1-containing neurones displayed increased levels of HSPA1A, while DNAJB1 was sequestered into the NNI. Conclusion: Based on our results, we propose a model for the aggregation-associated pathology of spinocerebellar ataxia type 3: GCS and DNS aggregation likely represents early stages of pathology, which progresses towards formation of p62-positive NNI. A fraction of NNI exhibits UBB+1 staining, implying proteasomal overload at a later stage. Subsequently, the stress-inducible HSPA1A is elevated while DNAJB1 is recruited into NNIs. This indicates that the stress response is only induced late when all endogenous protein quality control systems have failed. [ABSTRACT FROM AUTHOR]

L. Chadwick, L. Gentle, J. Strachan and R. Layfield (2012) Neuropathology and Applied Neurobiology 38, 118-131 Unchained maladie - a reassessment of the role of Ubb+1-capped polyubiquitin chains in Alzheimer's disease Molecular misreading allows the formation of mutant proteins in the absence of gene mutations. A mechanism has been proposed by which a frameshift mutant of the ubiquitin protein, Ubb+1, which accumulates in an age-dependent manner as a result of molecular misreading, contributes to neuropathology in Alzheimer's disease (Lam et al. 2000). Specifically, in the Ubb+1-mediated proteasome inhibition hypothesis Ubb+1'caps' unanchored (that is, nonsubstrate linked) polyubiquitin chains, which then act as dominant inhibitors of the 26S proteasome. A review of subsequent literature indicates that this original hypothesis is broadly supported, and offers new insights into the mechanisms accounting for the age-dependent accumulation of Ubb+1, and how Ubb+1-mediated proteasome inhibition may contribute to Alzheimer's disease. Further, recent studies have highlighted a physiological role for free endogenous unanchored polyubiquitin chains in the direct activation of certain protein kinases. This raises the possibility that Ubb+1-capped unanchored polyubiquitin chains could also exert harmful effects through the aberrant activation of tau or other ubiquitin-dependent kinases, neuronal NF-κB activity or NF-κB-mediated neuroinflammatory processes. [ABSTRACT FROM AUTHOR]

Huntington’s disease (HD) is a devastating neurodegenerative disorder caused by an expanded polyglutamine repeat within the N-terminus of the huntingtin protein. It is characterized by a selective loss of medium spiny neurons in the striatum. It has been suggested that impaired proteasome function and endoplasmic reticulum (ER) stress play important roles in mutant huntingtin (mHtt)-induced cell death. However, the molecular link involved is poorly understood. In the present study, we identified the essential role of the extra long form of Bim (Bcl-2 interacting mediator of cell death), BimEL, in mHtt-induced cell death. BimEL protein expression level was significantly increased in cell lines expressing the N-terminus of mHtt and in a mouse model of HD. Although quantitative RT-PCR analysis indicated that BimEL mRNA was increased in cells expressing mHtt, we provided evidence showing that, at the post-translational level, phosphorylation of BimEL played a more important role in regulating BimEL expression. Up-regulation of BimEL facilitated the translocation of Bax to the mitochondrial membrane, which further led to cytochrome c release and cell death. On the other hand, knocking down BimEL expression prevented mHtt-induced cell death. Taken together, these findings suggest that BimEL is a key element in regulating mHtt-induced cell death. A model depicting the role of BimEL in linking mHtt-induced ER stress and proteasome dysfunction to cell death is proposed. [ABSTRACT FROM AUTHOR]

• Introduction • Protein aggregation - ‘Toxic oligomer’ hypothesis - Protein (mis)folding - Proteostasis and molecular chaperones - Protein misfolding and endoplasmic reticulum stress - Unfolded protein response - Interaction of proteins - The ubiquitin proteasome system - Autophagy and neurodegeneration - UPS in neurodegenerative disorders - Aggresomes • Oxidative injury - Metals and oxidative stress - Oxidative stress in Alzheimer disease - Oxidative stress in Parkinson disease - Oxidative stress in other neurodegenerative disorders • Impaired bioenergetics and mitochondrial dysfunction - Mitochondrial dysfunction in Alzheimer and Parkinson disease • Fragmentation of neuronal Golgi apparatus • Disruption of cellular/axonal transport - Axonal transport in tauopathies - Axonal transport in synucleinopathies - Axonal transport in other neurodegenerative diseases • Dysfunction of neurotrophins • ‘Neuroinflammatory’ processes • The final pathway: multifaceted neuronal death • Cell death cascades in major NDDs • Acknowledgements Neurodegenerative diseases are characterized by progressive dysfunction of specific populations of neurons, determining clinical presentation. Neuronal loss is associated with extra and intracellular accumulation of misfolded proteins, the hallmarks of many neurodegenerative proteinopathies. Major basic processes include abnormal protein dynamics due to deficiency of the ubiquitin–proteosome–autophagy system, oxidative stress and free radical formation, mitochondrial dysfunction, impaired bioenergetics, dysfunction of neurotrophins, ‘neuroinflammatory’ processes and (secondary) disruptions of neuronal Golgi apparatus and axonal transport. These interrelated mechanisms lead to programmed cell death is a long run over many years. Neurodegenerative disorders are classified according to known genetic mechanisms or to major components of protein deposits, but recent studies showed both overlap and intraindividual diversities between different phenotypes. Synergistic mechanisms between pathological proteins suggest common pathogenic mechanisms. Animal models and other studies have provided insight into the basic neurodegeneration and cell death programs, offering new ways for future prevention/treatment strategies. [ABSTRACT FROM AUTHOR]

The nuclear–cytoplasmic shuttling protein RBCC protein interacting with protein kinase C1 (RBCK1) possesses transcriptional and ubiquitin ligase activities. We have recently reported that RBCC protein interacting with protein kinase C2 (RBCK2), a RING–in-between-RING fingers domain-lacking splice variant of RBCK1, lacks transcriptional activity, but rather represses the RBCK1-mediated transcriptional activity as a cytoplasmic tethering protein for RBCK1. In this study, we have found that RBCK2 overexpressed in human embryonic kidney 293 cells interacts with the polyubiquitin chain and the polyubiquitin-interacting subunit S5a, and significantly increases the intracellular amount of polyubiquitinated proteins. These results strongly suggested that RBCK2 functions as an adaptor protein for the polyubiquitinated protein and the S5a subunit in 26S proteasome through its novel zinc finger motif and ubiquitin-like domain, respectively, presumably delivering the polyubiquitinated proteins to the entrance of the 26S proteasome catalytic domain for degradation. Structured digital abstract • : S5a (uniprotkb: ) binds ( ) to Rbck1 (uniprotkb: ) by pull down ( ) • : S5a (uniprotkb: ) physically interacts ( ) with Rbck1 (uniprotkb: ) by anti bait coimmunoprecipitation ( ) • : S5a (uniprotkb: ) physically interacts ( ) with Rbck1 (uniprotkb: ) by anti tag coimmunoprecipitation ( ) • : Rbck1 (uniprotkb: ) physically interacts ( ) with Ubiquitin (uniprotkb: ) by anti tag coimmunoprecipitation ( ) • : S5a (uniprotkb: ) binds ( ) to Ubiquitin (uniprotkb: ) by pull down ( ) • : Rbck1 (uniprotkb: ) binds ( ) to Ubiquitin (uniprotkb: ) by pull down ( ) [ABSTRACT FROM AUTHOR]

An erroneous transcriptional process, known as molecular misreading, gives rise to an alternative transcript of the ubiquitin B (UBB) gene. This transcript encodes the protein UBB+1, which comprises a ubiquitin moiety and a 19-aa C-terminal extension. UBB+1 is found in affected neurons in neurodegenerative diseases and behaves as an atypical ubiquitin fusion degradation (UFD) proteasome substrate that is poorly degraded and impedes the ubiquitin/proteasome system. Here, we show that the limited length of UBB+1 is responsible for its inefficient degradation and inhibitory activity. Designed UFD substrates with an equally short 19-aa or a 20-aa C-terminal extension were also poorly degraded and had a general inhibitory activity on the ubiquitin/proteasome system in two unrelated cell lines. Extending the polypeptide to 25 aa sufficed to convert the protein into an efficiently degraded proteasome substrate that lacked inhibitory activity. A similar length dependency was found for degradation of two UFD substrates in Saccharomyces cermyisiae, which suggests that the mechanisms underlying this length constraint are highly conserved. Extending UBB+1 also converted this protein into an efficient substrate of the proteasome. These observations provide an explanation for the accumulation of UBB+1 in neurodegenerative disorders and offers new insights into the physical constraints determining proteasomal degradation. [ABSTRACT FROM AUTHOR]

Gene transfer has proven to be an effective neurobiological tool in a number of neurodegenerative diseases, but it is not known if it can correct a sleep disorder. Narcolepsy is a neurodegenerative sleep disorder linked to the loss of neurons containing the neuropeptide orexin, also known as hypocretin. Here, a replication-defective herpes simplex virus-1 amplicon-based vector was constructed to transfer the gene for mouse prepro-orexin into mice with a genetic deletion of the orexin gene. After in vitro tests confirmed successful gene transfer into cells, the gene vector was delivered to the lateral hypothalamus of orexin knockout (KO) mice where the orexin peptide was robustly expressed in the somata and processes of numerous neurons, and the peptide product was detected in the cerebrospinal fluid. During the 4-day life-span of the vector the incidence of cataplexy declined by 60%, and the levels of rapid eye movement sleep during the second half of the night were similar to levels in wild-type mice, indicating that narcoleptic sleep–wake behavior in orexin KO mice can be improved by targeted gene transfer. [ABSTRACT FROM AUTHOR]

Age-related testosterone depletion in men is a risk factor for Alzheimer’s disease. Prior studies suggest that androgens affect Alzheimer’s disease risk by regulating accumulation of β-amyloid protein (Aβ) by an undefined mechanism. In this study, we investigated the role of the Aβ-catabolizing enzyme neprilysin (NEP) in this process. First, we observed that androgens positively regulate neural expression of NEP in adult male rats. Next, we investigated androgen regulatory effects on both NEP expression and Aβ levels using cultured hippocampal neurons and neuronally differentiated rat pheochromocytoma cell 12 with or without androgen receptor (AR). Dihydrotestosterone (DHT) induced a time-dependent increase in NEP expression. DHT also significantly decreased levels of Aβ in AR-expressing cells transfected with amyloid precursor protein, but did not affect levels of either full-length or non-amyloidogenic, soluble amyloid precursor protein. Importantly, the DHT induced decrease of Aβ was blocked by pharmacological inhibition of NEP. The DHT-mediated increase in NEP expression and decrease in Aβ levels were (i) not observed in rat pheochromocytoma cell 12 lacking AR and (ii) blocked in AR-expressing cells by the antagonists, cyproterone acetate and flutamide. Together, these findings suggest that androgen regulation of Aβ involves an AR-dependent mechanism requiring up-regulation of the Aβ catabolizing enzyme NEP. [ABSTRACT FROM AUTHOR]

Protein aggregates in muscle cells are the morphological hallmark of myofibrillar myopathies, including myotilinopathies and desminopathies. The aim of the present study is to analyse the expression of mutant ubiquitin (UBB+1), an aberrant form of ubiquitin which accumulates in certain disorders characterized by intracellular aggregates of proteins, and p62, a multimeric signal protein which plays an active role in aggregate formation, in muscle biopsies from patients suffering from myotilinopathy and desminopathy in order to gain understanding of the mechanisms leading to protein aggregation in these disorders. Single immunohistochemistry, and single- and double-labelling immunofluorescence and confocal microscopy for UBB+1 and p62, has been performed in muscle biopsies from patients suffering from myotilinopathy and desminopathy. Strong UBB+1 immunoreactivity, colocalizing with myotilin aggregates, was found in muscle fibres in myotilinopathies. UBB+1 accumulation, colocalizing with desmin aggregates, also occurs in desminopathies. In addition, strong p62 immunoreactivity colocalizing with myotilin aggregates was observed in myotilinopathies. Similarly, p62 immunoreactivity colocalizing with desmin aggregates was found in desminopathies. The present findings suggest that accumulation of protein aggregates in myotilinopathies and in desminopathies may be related with UBB+1/abnormal protein complexes which are resistant to proteasome degradation. Furthermore, these observations suggest a relationship between the presence of p62 and the formation of inclusions in different subtypes of myofibrillar myopathies. [ABSTRACT FROM AUTHOR]

Down syndrome (DS) patients suffer from mental retardation, but also display enhanced β-APP production and develop cortical amyloid plaques at an early age. As β-APP and Notch are both processed by γ-secretase, we analyzed expression of the Notch signaling pathway in the adult DS brain and in a model system for DS, human trisomy 21 fibroblasts by quantitative PCR. In adult DS cortex we found that Notchl, Dll1 and Hes1 expression is up-regulated. Moreover, DS fibroblasts and Alzheimer disease cortex also show overexpression of Notchl and Dll1, indicating that enhanced β-APP processing found in both DS and AD could be instrumental in these changes. Using pull-down studies we could demonstrate interaction of APP with Notch 1, suggesting that these transmembrane proteins form heterodimers, but independent of γ-secretase. We could demonstrate binding of the intracellular domain of Notch1 to the APP adaptor protein Fe65. Furthermore, activated Notch1 can transactivate an APP target gene, Kail, and vice versa, activated APP can trans-activate the classical Notch target gene Hes1. These data suggest that Notch expression is activated in Down syndrome, possibly through cross-talk with APP signaling. This interaction might affect brain development, since the Notch pathway plays a pivotal role in neuron-glia differentiation. [ABSTRACT FROM AUTHOR]

Molecular misreading of the ubiquitin-B (UBB) gene results in a dinucleotide deletion in UBB mRNA. The resulting mutant protein, UBB&sup+1;, accumulates in the neuropathological hallmarks of Alzheimer disease. In vitro, UBB&sup+1; inhibits proteasomal proteolysis, although it is also an ubiquitin fusion degradation substrate for the proteasome. Using the ligase chain reaction to detect dinucleotide deletions, we report here that UBB&sup+1; transcripts are present in each neurodegenerative disease studied (tauo- and synucleinopathies) and even in control brain samples. In contrast to UBB&sup+1; transcripts, UBB&sup+1; protein accumulation in the ubiquitin-containing neuropathological hallmarks is restricted to the tauopathies such as Pick disease, frontotemporal dementia, progressive supranuclear palsy, and argyrophilic grain disease. Remarkably, UBB&sup+1; protein is not detected in the major forms of synucleinopathies (Lewy body disease and multiple system atrophy). The neurologically intact brain can cope with UBB&sup+1; as lentivirally delivered UBB&sup+1; protein is rapidly degraded in rat hippocampus, whereas the K29,48R mutant of UBB&sup+1;, which is not ubiquitinated, is abundantly expressed. The finding that UBB&sup+1; protein only accumulates in tauopathies thus implies that the ubiquitin-proteasome system is impaired specifically in this group of neurodegenerative diseases and not in synucleinopathies and that the presence of UBB&sup+1; protein reports proteasomal dysfunction in the brain. [ABSTRACT FROM AUTHOR]

Summary The volatile anaesthetic sevoflurane is degraded to fluoride (F- ) and a vinyl ether (Compound A), which have the potential to harm kidney and liver. Whether renal and hepatic injuries can occur in horses is unknown. Cardiopulmonary, biochemical and histopathological changes were studied in six healthy thoroughbred horses undergoing 18 h of low-flow sevoflurane anaesthesia. Serum F- concentrations were measured and clinical laboratory tests performed to assess hepatic and renal function before and during anaesthesia. Necropsy specimens of kidney and liver were harvested for microscopic examination and compared to pre-experimental needle biopsies. Cardiopulmonary parameters were maintained at clinically acceptable levels throughout anaesthesia. Immediately after initiation of sevoflurane inhalation, serum F- levels began to rise, reaching an ongoing 38–45 μ mol l-1 plateau at 8 h of anaesthesia. Serum biochemical analysis revealed only mild increases in glucose and creatinine kinase and a decrease in total calcium. Beyond 10 h of anaesthesia mild, time-related changes in urine included increased volume, glucosuria and enzymuria. Histological examination revealed mild microscopic changes in the kidney involving mainly the distal tubule, but no remarkable alterations in liver tissue. These results indicate that horses can be maintained in a systemically healthy state during unusually prolonged sevoflurane anaesthesia with minimal risk of hepatocellular damage from this anaesthetic. Furthermore, changes in renal function and morphology observed after sevoflurane inhalation are judged minimal and appear to be clinically irrelevant; they may be the result of anaesthetic duration, physiological stressors, sevoflurane (or its degradation products) or other unknown factors associated with these animals and study conditions. [ABSTRACT FROM AUTHOR]