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Preclinical evidence suggests that antidepressants (ADs) may differentially influence mitochondrial energetics. This study was conducted to investigate the relationship between mitochondrial function and illness vulnerability in bipolar disorder (BD), specifically risk of treatment-emergent mania (TEM). Participants with BD already clinically phenotyped as TEM+ (n = 176) or TEM− (n = 516) were further classified whether the TEM associated AD, based on preclinical studies, increased (Mito+, n = 600) or decreased (Mito−, n = 289) mitochondrial electron transport chain (ETC) activity. Comparison of TEM+ rates between Mito+ and Mito− ADs was performed using generalized estimating equations to account for participants exposed to multiple ADs while adjusting for sex, age at time of enrollment into the biobank and BD type (BD-I/schizoaffective vs. BD-II). A total of 692 subjects (62.7% female, 91.4% White, mean age 43.0 ± 14.0 years) including 176 cases (25.3%) of TEM+ and 516 cases (74.7%) of TEM- with previous exposure to Mito+ and/or Mito- antidepressants were identified. Adjusting for age, sex and BD subtype, TEM+ was more frequent with antidepressants that increased (24.7%), versus decreased (13.5%) mitochondrial energetics (OR = 2.21; p = 0.000009). Our preliminary retrospective data suggests there may be merit in reconceptualizing AD classification, not solely based on monoaminergic conventional drug mechanism of action, but additionally based on mitochondrial energetics. Future prospective clinical studies on specific antidepressants and mitochondrial activity are encouraged. Recognizing pharmacogenomic investigation of drug response may extend or overlap to genomics of disease risk, future studies should investigate potential interactions between mitochondrial mechanisms of disease risk and drug response.

Congenital disorders of glycosylation are genetic disorders that occur due to defects in protein and lipid glycosylation pathways. A deficiency of N-glycanase 1, encoded by the NGLY1 gene, results in a congenital disorder of deglycosylation. The NGLY1 enzyme is mainly involved in cleaving N-glycans from misfolded, retro-translocated glycoproteins in the cytosol from the endoplasmic reticulum before their proteasomal degradation or activation. Despite the essential role of NGLY1 in deglycosylation pathways, the exact consequences of NGLY1 deficiency on global cellular protein glycosylation have not yet been investigated. We undertook a multiplexed tandem mass tags-labeling-based quantitative glycoproteomics and proteomics analysis of fibroblasts from NGLY1-deficient individuals carrying different biallelic pathogenic variants in NGLY1. This quantitative mass spectrometric analysis detected 8041 proteins and defined a proteomic signature of differential expression across affected individuals and controls. Proteins that showed significant differential expression included phospholipid phosphatase 3, stromal cell-derived factor 1, collagen alpha-1 (IV) chain, hyaluronan and proteoglycan link protein 1, and thrombospondin-1. We further detected a total of 3255 N-glycopeptides derived from 550 glycosylation sites of 407 glycoproteins by multiplexed N-glycoproteomics. Several extracellular matrix glycoproteins and adhesion molecules showed altered abundance of N-glycopeptides. Overall, we observed distinct alterations in specific glycoproteins, but our data revealed no global accumulation of glycopeptides in the patient-derived fibroblasts, despite the genetic defect in NGLY1. Our findings highlight new molecular and system-level insights for understanding NGLY1-CDDG.

TRAPPC9 deficiency is an autosomal recessive disorder mainly associated with intellectual disability (ID), microcephaly, and obesity. Previously, TRAPPC9 deficiency has not been associated with biochemical abnormalities.Exome sequencing was performed in 3 individuals with ID and dysmorphic features. N-Glycosylation analyses were performed in the patients' blood samples to test for possible congenital disorder of glycosylation (CDG). TRAPPC9 gene, TRAPPC9 protein expression, and N-glycosylation markers were assessed in patient fibroblasts. Complementation with wild-type TRAPPC9 and immunofluorescence studies to assess TRAPPC9 expression and localization were performed. The metabolic consequences of TRAPPC9 deficiency were evaluated using tracer metabolomics.All 3 patients carried biallelic missense variants in TRAPPC9 and presented with an N-glycosylation defect in blood, consistent with CDG type I. Extensive investigations in patient fibroblasts corroborated TRAPPC9 deficiency and an N-glycosylation defect. Tracer metabolomics revealed global metabolic changes with several affected glycosylation-related metabolites.We identified 3 TRAPPC9 deficient patients presenting with ID, dysmorphic features, and abnormal glycosylation. On the basis of our findings, we propose that TRAPPC9 deficiency could lead to a CDG (TRAPPC9-CDG). The finding of abnormal glycosylation in these patients is highly relevant for diagnosis, further elucidation of the pathophysiology, and management of the disease.

OBJECTIVE: Epalrestat, an aldose reductase inhibitor increases phosphomannomutase (PMM) enzyme activity in a PMM2-congenital disorders of glycosylation (CDG) worm model. Epalrestat also decreases sorbitol level in diabetic neuropathy. We evaluated the genetic, biochemical, and clinical characteristics, including the Nijmegen Progression CDG Rating Scale (NPCRS), urine polyol levels and fibroblast glycoproteomics in patients with PMM2-CDG. METHODS: We performed PMM enzyme measurements, multiplexed proteomics, and glycoproteomics in PMM2-deficient fibroblasts before and after epalrestat treatment. Safety and efficacy of 0.8 mg/kg/day oral epalrestat were studied in a child with PMM2-CDG for 12 months. RESULTS: PMM enzyme activity increased post-epalrestat treatment. Compared with controls, 24% of glycopeptides had reduced abundance in PMM2-deficient fibroblasts, 46% of which improved upon treatment. Total protein N-glycosylation improved upon epalrestat treatment bringing overall glycosylation toward the control fibroblasts' glycosylation profile. Sorbitol levels were increased in the urine of 74% of patients with PMM2-CDG and correlated with the presence of peripheral neuropathy, and CDG severity rating scale. In the child with PMM2-CDG on epalrestat treatment, ataxia scores improved together with significant growth improvement. Urinary sorbitol levels nearly normalized in 3 months and blood transferrin glycosylation normalized in 6 months. INTERPRETATION: Epalrestat improved PMM enzyme activity, N-glycosylation, and glycosylation biomarkers in vitro. Leveraging cellular glycoproteome assessment, we provided a systems-level view of treatment efficacy and discovered potential novel biosignatures of therapy response. Epalrestat was well-tolerated and led to significant clinical improvements in the first pediatric patient with PMM2-CDG treated with epalrestat. We also propose urinary sorbitol as a novel biomarker for disease severity and treatment response in future clinical trials in PMM2-CDG. ANN NEUROL 20219999:n/a-n/a. ispartof: ANNALS OF NEUROLOGY vol:90 issue:6 pages:887-900 ispartof: location:United States status: published

Summary Micro-electrode arrays (MEAs) are increasingly used to characterize neuronal network activity of human induced pluripotent stem cell (hiPSC)-derived neurons. Despite their gain in popularity, MEA recordings from hiPSC-derived neuronal networks are not always used to their full potential in respect to experimental design, execution, and data analysis. Therefore, we benchmarked the robustness of MEA-derived neuronal activity patterns from ten healthy individual control lines, and uncover comparable network phenotypes. To achieve standardization, we provide recommendations on experimental design and analysis. With such standardization, MEAs can be used as a reliable platform to distinguish (disease-specific) network phenotypes. In conclusion, we show that MEAs are a powerful and robust tool to uncover functional neuronal network phenotypes from hiPSC-derived neuronal networks, and provide an important resource to advance the hiPSC field toward the use of MEAs for disease phenotyping and drug discovery., Highlights • MEAs are a robust tool to model neuronal network functioning • Neuronal networks from different healthy donors show comparable network activity • MEAs are able to distinguish disease-specific neuronal network phenotypes • We provide recommendations to standardize neuronal network recordings on MEA, In this article, Mossink and colleagues demonstrate that micro-electrode arrays (MEAs) are a highly robust tool to uncover genotype/phenotype interactions in hiPSC-derived excitatory neuronal networks, and provide an important resource for the design, execution, and analysis of hiPSC-derived neuronal networks studies on MEA.

Policymakers aim to move toward animal-free alternatives for scientific research and have introduced very strict regulations for animal research. We argue that, for neuroscience research, until viable and translational alternatives become available and the value of these alternatives has been proven, the use of animals should not be compromised., We would like to thank Loren Frank, UCSF, USA; Sheena Josselyn, Hospital for Sick Children, University of Toronto, Canada; Shantanu Jadhav, Brandeis University, USA; the European Animal Research Association (EARA); the Federation of European Neuroscience Societies Committee on Animals in Research (CARE); the Swiss Society for Neuroscience; the Society for Neuroscience Committee on Animals in Research (CAR); and Stichting Informatie Dierproeven (the Dutch foundation for public information on animal testing: SID) for input on and support for this article.

TRIT1 defect is a rare, autosomal-recessive disorder of transcription, initially described as a condition with developmental delay, myoclonic seizures, and abnormal mitochondrial function. Currently, only 13 patients have been reported. We reviewed the genetic, clinical, and metabolic aspects of the disease in all known patients, including two novel, unrelated TRIT1 cases with abnormalities in oxidative phosphorylation complexes I and IV in fibroblasts. Taken together the features of all 15 patients, TRIT1 defect could be identified as a potentially recognizable syndrome including myoclonic epilepsy, speech delay, strabismus, progressive spasticity, and variable microcephaly, with normal lactate levels. Half of the patients had oxidative phosphorylation complex measurements and had multiple complex abnormalities.

Post-traumatic stress disorder (PTSD) is a debilitating psychiatric condition that precipitates in ~10% of individuals exposed to a traumatic event (TE). Symptoms include recurrent and intrusive thoughts, sleep disturbance, hypervigilance, exaggerated startle, and reckless or destructive behavior. Given the complex and heterogeneous nature of the disease, animal models for PTSD-like symptomatology are of increasing interest to the field of PTSD research. Because resilience to PTSD-like symptomatology is an important epidemiologic aspect of PTSD, animal models that resolve vulnerable and resilient animals are of particular value. Due to the complex nature of the PTSD phenotype and the potential overlaps between PTSD-like behavior and behaviors associated with other stress-induced psychopathologies such as anxiety or depression, animal models that utilize multiple readouts for PTSD-like behavior are also of increasing value. We utilize a paradigm developed by Lebow et al. 2012 for the induction and identification of PTSD-like symptomatology in mice. This paradigm utilizes inescapable electric foot shock, administered in two decontextualized sessions over two consecutive days. Stressed mice perform four behavioral tests - dark/light transfer, marble burying, acoustic startle, and home cage activity - to generate five behavioral readouts of PTSD-like behavior: % risk assessment (%RA), % marbles buried (%MB), % prepulse inhibition (%PPI), latency to peak startle amplitude (LPSA), and % light phase activity (%LPA). PTSD-like symptomatology is characterized by decreased %RA, increased %MB, decreased %PPI, decreased LPSA, and increased %LPA. The 20% of animals displaying the most PTSD-like behavior in each test are awarded a certain number of points depending on the test, and animals scoring sufficient points are designated as PTSD-like, while animals scoring no points are designated PTSD-resilient. This paradigm identifies PTSD-like behavior in ~15% of animals, a rate comparable to that observed in humans. This protocol represents a robust and reproducible paradigm for the induction of PTSD-like behavior in mice.

Introduction Congenital disorders of glycosylation (CDG) are inborn errors of glycan metabolism with high clinical variability. Only a few antenatal cases have been described with CDG. Due to a lack of reliable biomarker, prenatal CDG diagnostics relies primarily on molecular studies. In the presence of variants of uncertain significance prenatal glycosylation studies are very challenging. Case report A consanguineous couple had a history of second-trimester fetal demise with tetralogy of Fallot and skeletal dysplasia. In the consecutive pregnancy, the second trimester ultrasonography showed skeletal dysplasia, vermian hypoplasia, congenital heart defects, omphalocele and dysmorphic features. Prenatal chromosomal microarray revealed a large region of loss of heterozygosity. Demise occurred at 30 weeks. Fetal whole exome sequencing showed a novel homozygous likely pathogenic variant in ALG3 and a variant of uncertain significance in COG5. Methods Western blot was used to quantify ALG3, COG5, COG6, and the glycosylation markers ICAM-1 and LAMP2. RT-qPCR was used for ALG3 and COG5 expression in cultured amniocytes and compared to age matched controls. Results ALG3 and COG5 mRNA levels were normal. ICAM-1, LAMP2, ALG3 and COG5 levels were decreased in cultured amniocytes, suggesting the possible involvement of both genes in the complex phenotype. Conclusion This is the first case of successful use of glycosylated biomarkers in amniocytes, providing further options of functional antenatal testing in CDG.

Item does not contain fulltext Antidepressants have been shown to influence mitochondrial function directly, and suboptimal mitochondrial function (SMF) has been implicated in complex psychiatric disorders. In the current study, we used a mouse model for trait SMF to test the hypothesis that chronic fluoxetine treatment in mice subjected to chronic stress would negatively impact brain bioenergetics, a response that would be more pronounced in mice with trait SMF. In contrast, we hypothesized that chronic ketamine treatment would positively impact mitochondrial function in both WT and mice with SMF. We used an animal model for trait SMF, the Ndufs4(GT/GT) mice, which exhibit 25% lower mitochondrial complex I activity. In addition to antidepressant treatment, mice were subjected to chronic unpredictable stress (CUS). This paradigm is widely used to model complex behaviours expressed in various psychiatric disorders. We assayed several physiological indices as proxies for the impact of chronic stress and antidepressant treatment. Furthermore, we measured brain mitochondrial complex activities using clinically validated assays as well as established metabolic signatures using targeted metabolomics. As hypothesized, we found evidence that chronic fluoxetine treatment negatively impacted brain bioenergetics. This phenotype was, however, not further exacerbated in mice with trait SMF. Ketamine did not have a significant influence on brain mitochondrial function in either genotype. Here we report that trait SMF could be a moderator for an individual's response to antidepressant treatment. Based on these results, we propose that in individuals with SMF and comorbid psychopathology, fluoxetine should be avoided, whereas ketamine could be a safer choice of treatment.

Contains fulltext : 220691.pdf (Publisher’s version ) (Open Access) Invasive motor Cortex Stimulation (iMCS) was introduced in the 1990's for the treatment of chronic neuropathic orofacial pain (CNOP), although its effectiveness remains doubtful. However, CNOP is known to be a heterogeneous group of orofacial pain disorders, which can lead to different responses to iMCS. Therefore, this paper investigated (1) whether the effectiveness of iMCS is significantly different among different CNOP disorders and (2) whether other confounding factors can be impacting iMCS results in CNOP. A systematic review and meta-analysis using a linear mixed-model was performed. Twenty-three papers were included, totaling 140 CNOP patients. Heterogeneity of the studies showed to be 55.8%. A visual analogue scale (VAS) measured median pain relief of 66.5% (ranging from 0-100%) was found. Linear mixed-model analysis showed that patients suffering from trigeminal neuralgia responded significantly more favorable to iMCS than patients suffering from dysfunctional pain syndromes (p = 0.030). Also, patients suffering from CNOP caused by (supra)nuclear lesions responded marginally significantly better to iMCS than patients suffering from CNOP due to trigeminal nerve lesions (p = 0.049). No other confounding factors were elucidated. This meta-analysis showed that patients suffering from trigeminal neuralgia and patients suffering from (supra)nuclear lesions causing CNOP responded significantly more favorable than others on iMCS. No other confounding factors were found relevant.

Ischemic stroke accounts for over 80% of all strokes and is one of the leading causes of mortality and permanent disability worldwide. Intravenous administration of recombinant tissue plasminogen activator (rt-PA) is an approved treatment strategy for acute ischemic stroke of large arteries within 4.5 h of onset, and mechanical thrombectomy can be used for large arteries occlusion up to 24 h after onset. Improving diagnostic work up for acute treatment, reducing onset-to-needle time and urgent radiological access angiographic CT images (angioCT) and Magnetic Resonance Imaging (MRI) are real problems for many healthcare systems, which limits the number of patients with good prognosis in real world compared to the results of randomized controlled trials. The applied endovascular procedures demonstrated high efficacy, but some cellular mechanisms, following reperfusion, are still unknown. Changes in the morphology and function of mitochondria associated with reperfusion and ischemia-reperfusion neuronal death are still understudied research fields. Moreover, future research is needed to elucidate the relationship between continuously refined imaging techniques and the variable structure or physical properties of the clot along with vascular permeability and the pleiotropism of ischemic reperfusion lesions in the penumbra, in order to define targeted preventive procedures promoting long-term health benefits.

Contains fulltext : 287828.pdf (Publisher’s version ) (Open Access) Resilience to consequences of trauma exposure contains relevant information about the processes that contribute to the maintenance of mental health in the face of adversity; information that is essential to improve treatment success of stress-related mental diseases. Prior literature has implicated aberrant amygdala (re)activity as potential factor contributing to trauma susceptibility. However, it remains to be resolved which amygdalar subregions and neuronal subclasses are involved, and when - i.e., pre-, peri- or post-trauma exposure - and under what conditions changes in amygdala (re)activity manifest themselves. Here, we implemented a preclinical rodent model for PTSD that entailed exposure to a traumatic event (severe, unpredictable foot shock) followed by a trigger (mild, predictable foot shock). Using behavioral phenotyping, trauma susceptible vs. resilient mice were identified and pre-, peri- or post-trauma amygdala activity was compared. Neuronal activity was tagged in living mice by the use of the ArcTRAP transgenic mouse line, labeling all activated (i.e., Arc-expressing) neurons by a systemic injection of tamoxifen. Furthermore, we assessed amygdala responses during fear memory recall, induced by either (re-)exposure to the trauma, trigger, or a novel, yet similar context, and analyzed behavioral fear responses under these conditions, as well as basal anxiety in the mice. Results revealed no major differences dissociating susceptible vs. resilient mice prior to trauma exposure, but exaggerated activity in specifically the basolateral amygdala (BLA) peri-trauma that predicted susceptibility to later PTSD-like symptoms. Post-trauma, susceptible mice did not display altered basal amygdala activity, but BLA hyperreactivity in response to trigger context re-exposure, and BLA hyporesponsivity in response to the trauma context. Exposure to the novel, similar context evoked a differential temporal pattern of freezing behavior in susceptible mice and an increased activity of amygdalar somatostatin-expressing neurons specifically. As such, these results for the first time show that deviant BLA activity during fear learning predicts susceptibility to its long-term consequences and that aberrant subsequent BLA responses to stressful contexts depend on the exact context.

Contains fulltext : 249492.pdf (Publisher’s version ) (Open Access) The centrally-projecting Edinger-Westphal nucleus (EWcp) hosts a large population of neurons expressing urocortin 1 (Ucn1) and about half of these neurons also express the leptin receptor (LepRb). Previously, we have shown that the peripheral adiposity hormone leptin signaling energy surfeit modulates EWcp neurons' activity. Here, we hypothesized that Ucn1/LepRb neurons in the EWcp would act as a crucial neuronal node in the brain-white adipose tissue (WAT) axis modulating efferent sympathetic outflow to the WAT. We showed that leptin bound to neurons of the EWcp stimulated STAT3 phosphorylation, and increased Ucn1-production in a time-dependent manner. Besides, retrograde transneuronal tract-tracing using pseudorabies virus (PRV) identified EWcp Ucn1 neurons connected to WAT. Interestingly, reducing EWcp Ucn1 contents by ablating EWcp LepRb-positive neurons with leptin-saporin, did not affect food intake and body weight gain, but substantially (+26%) increased WAT weight accompanied by a higher plasma leptin level and changed plasma lipid profile. We also found that ablation of EWcp Ucn1/LepRb neurons resulted in lower respiratory quotient and oxygen consumption one week after surgery, but was comparable to sham values after 3 and 5 weeks of surgery. Taken together, we report that EWcp/LepRb/Ucn1 neurons not only respond to leptin signaling but also control WAT size and fat metabolism without altering food intake. These data suggest the existence of a EWcp-WAT circuitry allowing an organism to recruit fuels without being able to eat in situations such as the fight-or-flight response.

OBJECTIVE The primary objective of this anatomical study was to apply innovative imaging techniques to increase understanding of the microanatomical structures of the brainstem related to safe entry zones. The authors hypothesized that such a high-detail overview would enhance neurosurgeons’ abilities to approach and define anatomical safe entry zones for use with microsurgical resection techniques for intrinsic brainstem lesions. METHODS The brainstems of 13 cadavers were studied with polarized light imaging (PLI) and 11.7-T MRI. The brainstem was divided into 3 compartments—mesencephalon, pons, and medulla—for evaluation with MRI. Tissue was further sectioned to 100 μm with a microtome. MATLAB was used for further data processing. Segmentation of the internal structures of the brainstem was performed with the BigBrain database. RESULTS Thirteen entry zones were reported and assessed for their safety, including the anterior mesencephalic zone, lateral mesencephalic sulcus, interpeduncular zone, intercollicular region, supratrigeminal zone, peritrigeminal zone, lateral pontine zone, median sulcus, infracollicular zone, supracollicular zone, olivary zone, lateral medullary zone, and anterolateral sulcus. The microanatomy, safety, and approaches are discussed. CONCLUSIONS PLI and 11.7-T MRI data show that a neurosurgeon possibly does not need to consider the microanatomical structures that would not be visible on conventional MRI and tractography when entering the mentioned safe entry zones. However, the detailed anatomical images may help neurosurgeons increase their understanding of the internal architecture of the human brainstem, which in turn could lead to safer neurosurgical intervention.

Contains fulltext : 235749.pdf (Publisher’s version ) (Open Access) Exposure to antibiotic treatment has been associated with increased vulnerability to various psychiatric disorders. However, a research gap exists in understanding how adolescent antibiotic therapy affects behavior and cognition. Many antibiotics that target bacterial translation may also affect mitochondrial translation resulting in impaired mitochondrial function. The brain is one of the most metabolically active organs, and hence is the most vulnerable to impaired mitochondrial function. We hypothesized that exposure to antibiotics during early adolescence would directly affect brain mitochondrial function, and result in altered behavior and cognition. We administered amoxicillin, chloramphenicol, or gentamicin in the drinking water to young adolescent male wild-type mice. Next, we assayed mitochondrial oxidative phosphorylation complex activities in the cerebral cortex, performed behavioral screening and targeted mass spectrometry-based acylcarnitine profiling in the cerebral cortex. We found that mice exposed to chloramphenicol showed increased repetitive and compulsive-like behavior in the marble burying test, an accurate and sensitive assay of anxiety, concomitant with decreased mitochondrial complex IV activity. Our results suggest that only adolescent chloramphenicol exposure leads to impaired brain mitochondrial complex IV function, and could therefore be a candidate driver event for increased anxiety-like and repetitive, compulsive-like behaviors.

Contains fulltext : 235754.pdf (Publisher’s version ) (Closed access) Individuals with mitochondrial disease often present with psychopathological comorbidity, and mitochondrial dysfunction has been proposed as the underlying pathobiology in various psychiatric disorders. Several studies have suggested that medications used to treat neuropsychiatric disorders could directly influence mitochondrial function. This review provides a comprehensive overview of the effect of these medications on mitochondrial function. We collected preclinical information on six major groups of antidepressants and other neuropsychiatric medications and found that the majority of these medications either positively influenced mitochondrial function or showed mixed effects. Only amitriptyline, escitalopram, and haloperidol were identified as having exclusively adverse effects on mitochondrial function. In the absence of formal clinical trials, and until such trials are completed, the data from preclinical studies reported and discussed here could inform medication prescribing practices for individuals with psychopathology and impaired mitochondrial function in the underlying pathology.

Summary Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) is often caused by an adenine to guanine variant at m.3243 (m.3243A>G) of the MT-TL1 gene. To understand how this pathogenic variant affects the nervous system, we differentiated human induced pluripotent stem cells (iPSCs) into excitatory neurons with normal (low heteroplasmy) and impaired (high heteroplasmy) mitochondrial function from MELAS patients with the m.3243A>G pathogenic variant. We combined micro-electrode array (MEA) measurements with RNA sequencing (MEA-seq) and found reduced expression of genes involved in mitochondrial respiration and presynaptic function, as well as non-cell autonomous processes in co-cultured astrocytes. Finally, we show that the clinical phase II drug sonlicromanol can improve neuronal network activity when treatment is initiated early in development. This was intricately linked with changes in the neuronal transcriptome. Overall, we provide insight in transcriptomic changes in iPSC-derived neurons with high m.3243A>G heteroplasmy, and show the pathology is partially reversible by sonlicromanol., Highlights • High m.3243A>G heteroplasmy leads to neuronal network dysfunction • Expression of genes involved in mitochondrial and synaptic function are affected • Gene expression in co-cultured rat astrocytes is non-cell autonomously affected • Sonlicromanol partially rescues the network activity and transcriptome changes, Using human induced pluripotent stem cell-derived neurons with high levels of m.3243A>G heteroplasmy, Klein Gunnewiek et al. report on transcriptome changes underlying the functional neuronal network phenotype and show that sonlicromanol can partially improve both the neuronal network phenotype and the transcriptome changes.

Mitochondrial metabolism is increasingly implicated in psychopathologies and mood disorders, including post-traumatic stress disorder (PTSD). We recently reported that mice exposed to a novel paradigm for the induction of PTSD-like behavior displayed reduced mitochondrial electron transport chain (mtETC) complex activity as well as decreased multi-system fatty acid oxidation (FAO) flux. Based on these results, we hypothesized that stressed and PTSD-like animals would display evidence of metabolic reprogramming in both cerebellum and plasma consistent with increased energetic demand, mitochondrial metabolic reprogramming, and increased oxidative stress. We performed targeted metabolomics in both cerebellar tissue and plasma, as well as untargeted nuclear magnetic resonance (NMR) spectroscopy in the cerebellum of 6 PTSD-like and 7 resilient male mice as well as 7 trauma-naïve controls. We identified numerous differences in amino acids and tricarboxylic acid (TCA) cycle metabolite concentrations in the cerebellum and plasma consistent with altered mitochondrial energy metabolism in trauma exposed and PTSD-like animals. Pathway analysis identified metabolic pathways with significant metabolic pathway shifts associated with trauma exposure, including the tricarboxylic acid cycle, pyruvate, and branched-chain amino acid metabolism in both cerebellar tissue and plasma. Altered glutamine and glutamate metabolism, and arginine biosynthesis was evident uniquely in cerebellar tissue, while ketone body levels were modified in plasma. Importantly, we also identified several cerebellar metabolites (e.g. choline, adenosine diphosphate, beta-alanine, taurine, and myo-inositol) that were sufficient to discriminate PTSD-like from resilient animals. This multilevel analysis provides a comprehensive understanding of local and systemic metabolite fingerprints associated with PTSD-like behavior, and subsequently altered brain bioenergetics. Notably, several transformed metabolic pathways observed in the cerebellum were also reflected in plasma, connecting central and peripheral biosignatures of PTSD-like behavior. These preliminary findings could direct further mechanistic studies and offer insights into potential metabolic interventions, either pharmacological or dietary, to improve PTSD resilience., Graphical abstract Image 1, Highlights • Trauma-exposed mice display cerebellar and multi-system metabolic reprogramming. • Stressed mice display altered multisystem mitochondrial bioenergetics. • Cerebellar metabolites are sufficient discriminate PTSD-like and resilient mice. • Plasma metabolomics identifies potential dietary promotors of trauma resilience. • Cerebellar metabolic reprogramming is reflected in plasma biosignature.

Viruses spread between hosts through particles, but within hosts, viral genomes can spread from cell to cell through fusion, evading antiviral defenses and obviating costly infectious virion production1-3. Billions of electromechanically coupled cardiomyocytes (CMs) make myocardium inherently vulnerable to pathological electromechanical short circuits caused by intercellular viral spread 4-6. Beyond respiratory illness, COVID-19 affects the heart7 and cardiac injury and arrhythmias are serious public health concerns8-12. By studying myocardium of a young woman who died suddenly, diagnosed postmortem with COVID-19, we discovered highly focal myocardial SARS-CoV-2 infection spreading from one CM to another through intercellular junctions identified by highly concentrated sarcolemmal t-tubule viral spike glycoprotein. SARS-CoV-2 permissively infected beating human induced pluripotent stem cell (hiPSC)-CMs building multinucleated cardiomyotubes (CMTs) through cell type-specific fusion driven by proteolytically-activated spike glycoprotein. Recombinant spike glycoprotein, co-localizing to sarcolemma and sarcoplasmic reticulum, produced multinucleated CMTs with pathological structure, electrophysiology and Ca2+ excitation-contraction coupling. Blocking cleavage, a peptide-based protease inhibitor neutralized SARS-CoV-2 spike glycoprotein pathogenicity. We conclude that SARS-CoV-2 spike glycoprotein, efficiently primed, activated and strategically poised during biosynthesis, can exploit the CM’s inherent membranous connectivities to drive heart damage directly, uncoupling clinically common myocardial injury from lymphocytic myocarditis, often suspected but rarely confirmed in COVID-19.

SummaryMitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes (MELAS) is often caused by an adenine to guanine mutation at m.3243 (m.3243A>G) of the MT-TL1 gene (tRNAleu(UUR)). To understand how this mutation affects the nervous system, we differentiated human induced-pluripotent stem cells (iPSCs) into excitatory neurons with normal (low heteroplasmy) and impaired (high heteroplasmy) mitochondrial function from MELAS patients with the m.3243A>G mutation. We combined micro-electrode array (MEA) measurements with RNA sequencing (MEA-seq) and found that the m.3243A>G mutation affects expression of genes involved in mitochondrial respiration- and presynaptic function, as well as non-cell autonomous processes in co-cultured astrocytes. Finally, we show that the clinical II stage drug sonlicromanol (KH176) improved neuronal network activity in a patient-specific manner when treatment is initiated early in development. This was intricately linked with changes in the neural transcriptome. Overall, MEA-seq is a powerful approach to identify mechanisms underlying the m.3243A>G mutation and to study the effect of pharmacological interventions in iPSC-derived neurons.Highlights- High m.3243A>G heteroplasmy leads to lower neuronal network activity and synchronicity- High heteroplasmy affects expression of genes involved in mitochondrial ATP production and the synaptic function / the presynaptic vesicle cycle- High neuronal heteroplasmy non cell autonomously affects gene expression in healthy co-cultured astrocytes- Sonlicromanol partially rescues neuronal network activity and transcriptome changes induced by high heteroplasmyeTOC BlurbUsing human inducible pluripotent stem cell-derived neurons with high levels of m.3243A>G heteroplasmy, Klein Gunnewiek et al. show transcriptome changes underlying the functional neuronal network phenotype, and how sonlicromanol can partially improve both this neuronal network phenotype, and the transcriptome changes, in a patient-specific manner.

Mitochondria play a critical role in bioenergetics, enabling stress adaptation, and therefore, are central in biological stress responses and stress-related complex psychopathologies. To investigate the effect of mitochondrial dysfunction on the stress response and the impact on various biological domains linked to the pathobiology of depression, a novel mouse model was created. These mice harbor a gene trap in the first intron of the Ndufs4 gene (Ndufs4GT/GT mice), encoding the NDUFS4 protein, a structural component of complex I (CI), the first enzyme of the mitochondrial electron transport chain. We performed a comprehensive behavioral screening with a broad range of behavioral, physiological, and endocrine markers, high-resolution ex vivo brain imaging, brain immunohistochemistry, and multi-platform targeted mass spectrometry-based metabolomics. Ndufs4GT/GT mice presented with a 25% reduction of CI activity in the hippocampus, resulting in a relatively mild phenotype of reduced body weight, increased physical activity, decreased neurogenesis and neuroinflammation compared to WT littermates. Brain metabolite profiling revealed characteristic biosignatures discriminating Ndufs4GT/GT from WT mice. Specifically, we observed a reversed TCA cycle flux and rewiring of amino acid metabolism in the prefrontal cortex. Next, exposing mice to chronic variable stress (a model for depression-like behavior), we found that Ndufs4GT/GT mice showed altered stress response and coping strategies with a robust stress-associated reprogramming of amino acid metabolism. Our data suggest that impaired mitochondrial CI function is a candidate driver for altered stress reactivity and stress-induced brain metabolic reprogramming. These changes result in unique phenomic and metabolomic signatures distinguishing groups based on their mitochondrial genotype.

Phosphoglucomutase 1 (PGM1) encodes the metabolic enzyme that interconverts glucose-6-P and glucose-1-P. Mutations in PGM1 cause impairment in glycogen metabolism and glycosylation, the latter manifesting as a congenital disorder of glycosylation (CDG). This unique metabolic defect leads to abnormal N-glycan synthesis in the endoplasmic reticulum (ER) and the Golgi apparatus (GA). On the basis of the decreased galactosylation in glycan chains, galactose was administered to individuals with PGM1-CDG and was shown to markedly reverse most disease-related laboratory abnormalities. The disease and treatment mechanisms, however, have remained largely elusive. Here, we confirm the clinical benefit of galactose supplementation in PGM1-CDG-affected individuals and obtain significant insights into the functional and biochemical regulation of glycosylation. We report here that, by using tracer-based metabolomics, we found that galactose treatment of PGM1-CDG fibroblasts metabolically re-wires their sugar metabolism, and as such replenishes the depleted levels of galactose-1-P, as well as the levels of UDP-glucose and UDP-galactose, the nucleotide sugars that are required for ER- and GA-linked glycosylation, respectively. To this end, we further show that the galactose in UDP-galactose is incorporated into mature, de novo glycans. Our results also allude to the potential of monosaccharide therapy for several other CDG. ispartof: American Journal of Human Genetics vol:104 issue:5 pages:835-846 ispartof: location:United States status: Published online