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CD19 CAR-T cells have led to durable remissions in patients with refractory B-cell malignancies; nevertheless, most patients eventually relapse in the long term. Many interventions aimed at improving current products have been reported, with a subset of them focusing on a direct or indirect link to the metabolic state of the CAR-T cells. We assessed clinical products from an ongoing clinical trial utilizing CD19-28z CAR-T cells from patients with acute lymphoblastic leukemia. CAR-T clinical products leading to a complete response had significantly higher mitochondrial function (by oxygen consumption rate) irrespective of mitochondrial content. Next, we replaced the carbon source of the media from glucose to galactose to impact cellular metabolism. Galactose-containing media increased mitochondrial activity in CAR-T cells, and improved in in-vitro efficacy, without any consistent phenotypic change in memory profile. Finally, CAR-T cells produced in galactose-based glucose-free media resulted in increased mitochondrial activity. Using an in-vivo model of Nalm6 injected mice, galactose-primed CAR-T cells significantly improved leukemia-free survival compared to standard glucose-cultured CAR-T cells. Our results prove the significance of mitochondrial metabolism on CAR-T cell efficacy and suggest a translational pathway to improve clinical products., (© 2024. The Author(s), under exclusive licence to Springer Nature Limited.)

Background: Conventional oral levodopa therapy for the treatment of Parkinson's disease can be associated with variations in plasma concentrations. Levodopa infusion strategies might provide more consistent drug delivery and fewer motor fluctuations. We aimed to assess the safety and efficacy of a continuous 24 h/day subcutaneous infusion of ND0612 (a levodopa-carbidopa solution) compared with oral immediate-release levodopa-carbidopa for the treatment of motor fluctuations in people with Parkinson's disease., Methods: We conducted a phase 3, randomised, double-blind, double-dummy, active-controlled, multicentre trial at 117 academic and community neurology sites in 16 countries, including in Europe, Israel, and the USA. Eligible participants were men and women aged 30 years or older with a diagnosis of Parkinson's disease (Hoehn and Yahr stage ≤3 in the on state) who experienced at least 2·5 h/day of off time. Participants underwent an open-label run-in phase (<12 weeks), during which time optimal regimens were established for both oral immediate-release levodopa-carbidopa and for 24 h/day subcutaneous ND0612 infusion (levodopa-carbidopa 60·0/7·5 mg/mL), with supplemental oral levodopa-carbidopa if needed. Participants were then randomly assigned (1:1) to 12 weeks of double-blind treatment with their optimised regimen of either subcutaneous ND0612 or oral levodopa-carbidopa, with matching oral or subcutaneous placebo given as required to maintain blinding. Randomisation was done via an interactive web response system, stratified by region, using a permuted block schedule. Participants, study partners, treating investigators, study site personnel, and the sponsor were masked to treatment group allocation. The primary efficacy endpoint was the change from baseline (ie, time of randomisation, when all patients were receiving an optimised open-label ND0612 regimen) to end of the double-blind phase in total daily on time without troublesome dyskinesia, analysed by intention to treat. This trial is registered with ClinicalTrials.gov, NCT04006210, and is complete., Findings: Between Sept 30, 2019, and April 8, 2022, 381 participants were enrolled, of whom 259 (68%) were randomly assigned, 128 (49%) to subcutaneous ND0612 and 131 (51%) to oral levodopa-carbidopa. 243 (94%) participants completed the study. Treatment with subcutaneous ND0612 provided an additional 1·72 h (95% CI 1·08 to 2·36) of on time without troublesome dyskinesia compared with oral levodopa-carbidopa (change from baseline of -0·48 h [-0·94 to -0·02] with subcutaneous ND0612 vs -2·20 h [-2·65 to -1·74] with oral levodopa-carbidopa; p<0·0001). Significant treatment differences favouring subcutaneous ND0612 were also found in the first four of nine prespecified hierarchical outcomes of daily off time (-1·40 h [95% CI -1·99 to -0·80]), Movement Disorders Society-Unified Parkinson's Disease Rating Scale part II scores (-3·05 [-4·28 to -1·81]), Patients Global Impression of Change (odds ratio [OR] 5·31 [2·67 to 10·58]), and Clinical Global Impression of Improvement (OR 7·23 [3·57 to 14·64]). Hierarchical testing ended after the fourth secondary endpoint. Adverse events were reported by 287 (89%) of 322 participants during open-label ND0612 optimisation, and by 103 (80%) of 128 in the ND0612 group and 97 (74%) of 131 in the oral levodopa-carbidopa group during the double-blind phase. The most common adverse events were infusion-site reactions (266 [83%] participants during open-label ND0612, and 73 [57%] in the ND0612 group vs 56 [43%] in the oral levodopa-carbidopa group during the double-blind phase), most of which were mild. Serious adverse events in four participants in the ND0612 group were related to study treatment (infusion-site cellulitis [n=2], infusion-site abscess and infusion-site ulcer [n=1]; and paraesthesia and peripheral sensorimotor neuropathy [n=1]). One participant in the ND0612 group died during the double-blind phase, but the death was not related to study treatment (fall leading to traumatic brain injury)., Interpretation: Results of this phase 3 study showed that subcutaneous ND0612 used in combination with oral immediate-release levodopa-carbidopa increased on time without troublesome dyskinesia and reduced off time, with a favourable benefit-risk profile. ND0612 might offer a safe and efficacious subcutaneous levodopa infusion approach to managing motor fluctuations in people with Parkinson's disease. The ongoing open-label extension phase will provide further information on the long-term efficacy and safety of treatment., Funding: NeuroDerm., Competing Interests: Declaration of interests AJE, FS, RP, AA, AE, JJF, NG, TG, SH-B, JH-V, SHI, KK, PAL, LL-M, WP, HS, and OR were investigators in the study and they or their institution received fees for participation. CWO and KK have stock ownership in Clintrex, which was contracted by NeuroDerm to provide services for this study. TY, LA, LS, NL, and NS are employed by NeuroDerm. RC was employed by NeuroDerm at the time of the study and is now employed by Mitsubishi Tanabe Pharma America. AJE has received grant support from the National Institutes of Health and the Michael J Fox Foundation; personal compensation as a consultant or scientific advisory board member for NeuroDerm, Herantis Pharma, Amneal, Acadia, Acorda, Kyowa Kirin, Sunovion, and Supernus; personal compensation as honoraria for speakership for Avion; and publishing royalties from Lippincott Williams & Wilkins, Cambridge University Press, and Springer. AJE cofounded REGAIN Therapeutics (a biotech startup developing non-aggregating peptide analogues as replacement therapies for neurodegenerative diseases) and is co-owner of a patent that covers synthetic soluble non-aggregating peptide analogues as replacement treatments in proteinopathies. FS reports honoraria and consulting fees from BIAL, Sunovion, AbbVie, Luosofarmaco, Kyowa, Synagile, Lundbeck, TEVA, UCB, Zambon, Blue Rock, NeuroDerm, Contera, Zambon, Biogen, Ever, and Britannia; speaker fees from BIAL, Sunovion, AbbVie, Luosofarmaco, Kjowa, Synagile, Lundbeck, TEVA, UCB, and Zambon; and travel support from Bial, Zambon, Synagile, and AbbVie. RP reports grants from Abbott, AbbVie, Alexza, Annovis, Biogen, Bluerock, Bukwang, Cerevel, Global Kinetics, Jazz, the Michael J Fox Foundation, NeuroDerm, Neuraly, the Parkinson's Foundation, Praxis, Roche, Sage, Scion, Sun Pharma, UCB, and Voyager; and consulting fees from Abbott, AbbVie, ACADIA, Acorda, Allevion, Amneal, Artemida, BioVie, CalaHealth, Convatec, Global Kinetics, Inbeeo, Insightec, Jazz, Kyowa, Lundbeck, Merz, Neurocrine, NeuroDerm, Ono, PhotoPharmics, Sage, Sunovion, Supernus, UCB, and Wren. AA has received speaker's honoraria from Ipsen and Merz; is President of the International Association on Parkinsonism and Related Disorders; and is Section Editor for Frontiers in Movement Disorders. AE reports honoraria and consulting fees from AbbVie, Acadia, Acorda, Adamas, Affiris, Allergan, Arbor, Biohaven, BioVie, Cerevel, Ipsen, Mitsubishi Tanabe Pharma America, NeuroDerm, Praxis, Revance, Supernus, Teva, US WorldMeds, and XW Labs. JJF has provided consultancy for AbbVie, BIAL, Biogen, Lundbeck, and Sunovion; received grants from Angelini, Novartis, Medtronic, AbbVie, Zambon, BIAL, Biogen, and Grunenthal; and received speaker fees for BIAL, Ono, SK Chemical, and Infucure. NG serves as consultant to NeuroDerm, Sanofi, and Biogen. NG also reports payment for lectures, travel support, or both from BIAL, NeuroDerm, and Biogen; stock options in Vibrant and Longevity AI; and a patent pending for GaitBetter. TG has served as consultant to NeuroDerm, AbbVie, Medisson, Truemed, and Tradis Gat; has received research support from the Movement Disorders Society; and has received the Center of Excellence grant from the Parkinson's Foundation. TG reports fees for lectures, travel support, or both from AbbVie, Medisson, Teva, Boston Scientific, and Alphamedix; stock options in Cytora and Neurosteer; and a patent for an automated analysis of speech and development of vocal biomarkers in Parkinson's disease. SH-B serves as consultant to NeuroDerm, AbbVie, Teva, Takeda, Medison, Trumed, and Abbott; has received payment for lectures from AbbVie, Medisson, and Teva; and has received research support from AbbVie and the Michael J Fox Foundation. JH-V reports grants from Fondo de Investigación Sanitaria; honoraria for lectures, travel support, or both from BIAL, Zambon, Italfarmaco, and AbbVie; and stock in Sense4care. SHI reports honoraria for CME, consultant fees, research grants, or promotional speaker fees on behalf of AbbVie, Acadia, Acorda, Adamas, Addex, Affiris, Alexva, Allergan, Amarantus, Amneal, Aptinyx, Axial, Axovant, Benevolent, Biogen, Britannia, Cadent, Cala, Cerecor, Cerevel, Cipla, Eli Lilly, Enterin, GE Healthcare, Global Kinetics, Impax, Impel, Intec Pharma, Ipsen, Jazz, Kyowa, Lundbeck, Merz, the Michael J Fox Foundation, Mitsubishi Tanabe, Neuralys, Neurocrine, NeuroDerm, Parkinson Study Group, Pharma2B, Prilenia, Promentis, Revance, Roche, Sanofi, Sunovion, Sun Pharma, Supernus, Teva, Theravance, UCB, and Zambon. KK reports equity interest in Clintrex and Hoover Brown; patents for information management; and participation in safety monitoring boards for Roche, Lilly, and Janssen. PAL reports advisory roles for Abide, Acorda Therapeutics, Adamas, Amneal, Aptinyx, Biogen, Britannia, Bukwang Pharma, Cavion, Cerevel, Denali, F Hoffmann–La Roche, Jazz Pharmaceuticals, Kyowa Kirin Hakko, Neurocrine, Mitsubishi NeuroDerm, Sage, Supernus, and US WorldMeds; and research grant support from the Michael J Fox Foundation, NeuroDerm, Parkinson Study Group, Pharma Two B, Hoffmann–La Roche, Sunovion, Sun Pharma, and US WorldMeds. CWO reports equity interest in Clintrex and expert witness testimony in the Paraquat litigation. WP has received lecture fees and honoraria for consultancy in relation to clinical drug development programs from AbbVie, AC Immune, Alterity, BIAL, Boehringer, Britannia, Lilly, Eisai, Lundbeck, Roche, Takeda, Britannia, Eisai, Roche, Stada, and Zambon; grant support from the Michael J Fox Foundation and the EU FP7 & Horizon 2020 programs; and safety monitoring board membership for UCB. WP also reports leadership roles in the Movement Disorder Society, Austrian Society of Neurology, and Austrian Parkinson's disease Society. HS reports consultancy fees from Novo Nordisk, Blue Rock Therapeutics, and Neurocrine; clinical trial support from Insightec, Sun Pharmaceuticals, Prevail Therapeutics, Blue Rock Therapeutics, Novo Nordisk, Biogen, Genentech–Roche, Bukwang, and the National Institutes of Health. OR has participated in advisory boards or provided consultancy for AbbVie, Adamas, Acorda, Addex, AlzProtect, ApoPharma, AstraZeneca, Axovant, Bial, Biogen, Britannia, Buckwang, CereSpir, Clevexel, Denali, INC Research, IPMDS, Lundbeck, Lupin, Merck, MundiPharma, NeurATRIS, NeuroDerm, Novartis, ONO Pharma, Osmotica, Parexel, Pfizer, Prexton Therapeutics, Quintiles, Roche, Sanofi, Servier, Sunovion, Theranexus, Takeda, Teva, UCB, Vectura, Watermark Research, XenoPort, XO, and Zambon; and has received grants from Agence Nationale de la Recherche, CHU de Toulouse, France-Parkinson, INSERM-DHOS Recherche Clinique Translationnelle, the Michael J Fox Foundation, Programme Hospitalier de Recherche Clinique, European Commission (FP7 and H2020), and Cure Parkinson's., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Mitochondrial dysfunction can be associated with a range of clinical manifestations. Here, we report a family with a complex phenotype including combinations of connective tissue, neurological, and metabolic symptoms that were passed on to all surviving children. Analysis of the maternally inherited mtDNA revealed a novel genotype encompassing the haplogroup J - defining mitochondrial DNA (mtDNA) ND5 m.13708G>A (A458T) variant arising on the mtDNA haplogroup H7A background, an extremely rare combination. Analysis of transmitochondrial cybrids with the 13708A-H7 mtDNA revealed a lower mitochondrial respiration, increased reactive oxygen species production (mROS), and dysregulation of connective tissue gene expression. The mitochondrial dysfunction was exacerbated by histamine, explaining why all eight surviving children inherited the dysfunctional histidine decarboxylase allele (W327X) from the father. Thus, certain combinations of common mtDNA variants can cause mitochondrial dysfunction, mitochondrial dysfunction can affect extracellular matrix gene expression, and histamine-activated mROS production can augment the severity of mitochondrial dysfunction. Most important, we have identified a previously unreported genetic cause of mitochondrial disorder arising from the incompatibility of common, nonpathogenic mtDNA variants.

Objective: Mitochondrial disorders are often characterized by muscle weakness and fatigue. Null mutations in the heart-muscle adenine nucleotide translocator isoform 1 (ANT1) of both humans and mice cause cardiomyopathy and myopathy associated with exercise intolerance and muscle weakness. Here we decipher the molecular underpinnings of ANT1-deficiency-mediated exercise intolerance., Methods: This was achieved by correlating exercise physiology, mitochondrial function and metabolomics of mice deficient in ANT1 and comparing this to control mice., Results: We demonstrate a peripheral limitation of skeletal muscle mitochondrial respiration and a reduced complex I respiration in ANT1-deficient mice. Upon exercise, this results in a lack of NAD + leading to a substrate limitation and stalling of the TCA cycle and mitochondrial respiration, further limiting skeletal muscle mitochondrial respiration. Treatment of ANT1-deficient mice with nicotinamide riboside increased NAD + levels in skeletal muscle and liver, which increased the exercise capacity and the mitochondrial respiration., Conclusion: Increasing NAD +  levels with nicotinamide riboside can alleviate the exercise intolerance associated to ANT1-deficiency, indicating the therapeutic potential of NAD + -stimulating compounds in mitochondrial myopathies., (Copyright © 2022 The Author(s). Published by Elsevier GmbH.. All rights reserved.)

Background: Continuous, subcutaneous (SC) levodopa/carbidopa infusion with ND0612 is under development as a treatment for patients with Parkinson's disease (PD) and motor fluctuations., Objective: Evaluate 1-year safety data., Methods: BeyoND is an open-label study evaluating the long-term safety of two ND0612 dosing regimens., Results: Of the 214 enrolled patients (24-hour SC infusion: n = 90; 16-hour SC infusion: n = 124), 120 (56%) completed 12 months of treatment. Leading causes for study discontinuation were consent withdrawal (19.6%) and adverse events (17.3%). Rates of discontinuation were reduced from 49% to 29% after a protocol revision and retraining. Systemic safety was typical for PD patients treated with levodopa/carbidopa. Most patients experienced infusion site reactions, particularly nodules (30.8%) and hematoma (25.2%), which were judged mostly mild to moderate and led to discontinuation in only 10.3% of the participants., Conclusions: Subcutaneous levodopa/carbidopa continuous infusion with ND0612 is generally safe, with typical infusion site reactions for SC delivery as the main adverse event. © 2021 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society., (© 2021 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.)

Autism spectrum disorders (ASDs) are characterized by a deficit in social communication, pathologic repetitive behaviors, restricted interests, and electroencephalogram (EEG) aberrations. While exhaustive analysis of nuclear DNA (nDNA) variation has revealed hundreds of copy number variants (CNVs) and loss-of-function (LOF) mutations, no unifying hypothesis as to the pathophysiology of ASD has yet emerged. Based on biochemical and physiological analyses, it has been hypothesized that ASD may be the result of a systemic mitochondrial deficiency with brain-specific manifestations. This proposal has been supported by recent mitochondrial DNA (mtDNA) analyses identifying both germline and somatic mtDNA variants in ASD. If mitochondrial defects do predispose to ASD, then mice with certain mtDNA mutations should present with autism endophenotypes. To test this prediction, we examined a mouse strain harboring an mtDNA ND6 gene missense mutation (P25L). This mouse manifests impaired social interactions, increased repetitive behaviors and anxiety, EEG alterations, and a decreased seizure threshold, in the absence of reduced hippocampal interneuron numbers. EEG aberrations were most pronounced in the cortex followed by the hippocampus. Aberrations in mitochondrial respiratory function and reactive oxygen species (ROS) levels were also most pronounced in the cortex followed by the hippocampus, but absent in the olfactory bulb. These data demonstrate that mild systemic mitochondrial defects can result in ASD without apparent neuroanatomical defects and that systemic mitochondrial mutations can cause tissue-specific brain defects accompanied by regional neurophysiological alterations., Competing Interests: Competing interest statement: D.C.W. has informal associations with MitoCURIAi and Mitrios. He is a consultant for Pano Therapeutics, Inc. and received funding from SP Accure Lab, Ltd., (Copyright © 2021 the Author(s). Published by PNAS.)

Background: ND0612 is a continuous, subcutaneous levodopa/carbidopa delivery system in development for patients with Parkinson's disease (PD) experiencing motor fluctuationsObjective:Evaluate the efficacy and safety of two ND0612 dosing regimens in patients with PD., Methods: This was a 28-day open-label study (NCT02577523) in PD patients with ≥2.5 hours/day of OFF time despite optimized treatment. Patients were randomized to treatment with either a 24-hour infusion (levodopa/carbidopa dose of 720/90 mg) or a 14-hour 'waking-day' infusion (levodopa/carbidopa dose of 538/68 mg plus a morning oral dose of 150/15 mg). Supplemental oral doses of levodopa were permitted for patients in both groups if required. In-clinic assessments of OFF time (primary endpoint) and ON time with or without dyskinesia were determined by a blinded rater over 8 hours (normalized to 16 hours)., Results: A total of 38 patients were randomized and 33 (87%) completed the study. Compared to baseline, OFF time for the overall population was reduced by a least squares (LS) mean[95% CI] of 2.0[- 3.3, - 0.7] hours (p = 0.003). ON time with no/mild dyskinesia (no troublesome dyskinesia) was increased from baseline by a LS mean of 3.3[2.0, 4.6] hours (p < 0.0001), and ON time with moderate/severe dyskinesia was reduced by a LS mean of 1.2[- 1.8, - 0.5] hours (p≤0.001). Reduction in OFF time was larger in the 24-hour group (- 2.8[- 4.6, - 0.9] hours; p = 0.004) than in the 14-hour group (- 1.3[- 3.1, 0.5] hours; p = 0.16). Complete resolution of OFF time was observed in 42% (n = 8) of patients in the 24-hour group. Infusion site reactions were the most common adverse event., Conclusion: This study demonstrates the feasibility and safety of continuous subcutaneous delivery of levodopa as a treatment for PD and provides preliminary evidence of efficacy.

Changes in the gut microbiota and the mitochondrial genome are both linked with the development of disease. To investigate why, we examined the gut microbiota of mice harboring various mutations in genes that alter mitochondrial function. These studies revealed that mitochondrial genetic variations altered the composition of the gut microbiota community. In cross-fostering studies, we found that although the initial microbiota community of newborn mice was that obtained from the nursing mother, the microbiota community progressed toward that characteristic of the microbiome of unfostered pups of the same genotype within 2 months. Analysis of the mitochondrial DNA variants associated with altered gut microbiota suggested that microbiome species diversity correlated with host reactive oxygen species (ROS) production. To determine whether the abundance of ROS could alter the gut microbiota, mice were aged, treated with N -acetylcysteine, or engineered to express the ROS scavenger catalase specifically within the mitochondria. All three conditions altered the microbiota from that initially established. Thus, these data suggest that the mitochondrial genotype modulates both ROS production and the species diversity of the gut microbiome, implying that the connection between the gut microbiome and common disease phenotypes might be due to underlying changes in mitochondrial function., (Copyright © 2019 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.)

Introduction: Sialic acids are important contributors to the polyanionic component of the glomerular filtration barrier, which regulates permeability selectivity. Pathologic glomerular hyposialylation, associated with podocyte effacement, has been implicated in human and mouse glomerulopathies. Oral treatment with N -acetylmannosamine (ManNAc), the uncharged precursor of sialic acid, ameliorates glomerular pathology in different models of glomerular disease., Methods: Here we explore the sialylation status of kidney biopsies obtained from 27 subjects with various glomerular diseases using lectin histochemistry., Results: We identified severe glomerular hyposialylation in 26% of the biopsies. These preliminary findings suggest that this condition may occur relatively frequently and may be a novel target for therapy. We describe the background, rationale, and design of a phase 1 study to test safety, tolerability, and pharmacokinetics of ManNAc in subjects with primary podocyte diseases., Conclusion: We recently demonstrated that ManNAc was safe and well tolerated in a first-in-human phase 1 study in subjects with UDP- N -acetylglucosamine (GlcNAc) 2-epimerase/ManNAc kinase (GNE) myopathy, a disorder of impaired sialic acid synthesis. Using previous preclinical and clinical data, we propose to test ManNAc therapy for subjects with primary glomerular diseases. Even though the exact mechanisms, affected cell types, and pathologic consequences of glomerular hyposialylation need further study, treatment with this physiological monosaccharide could potentially replace or supplement existing glomerular diseases therapies.

microRNAs (miRNAs) are critical for neuronal function and their dysregulation is repeatedly observed in neurodegenerative diseases. Here, we implemented high content image analysis for investigating the impact of several miRNAs in mouse primary motor neurons. This survey directed our attention to the neuron-specific miR-124, which controls axonal morphology. By performing next generation sequencing analysis and molecular studies, we characterized novel roles for miR-124 in control of mitochondria localization and function. We further demonstrated that the intermediate filament Vimentin is a key target of miR-124 in this system. Our data establishes a new pathway for control of mitochondria function in motor neurons, revealing the value of a neuron-specific miRNA gene as a mechanism for the re-shaping of otherwise ubiquitously-expressed intermediate filament network, upstream of mitochondria activity and cellular metabolism.

Primary coenzyme Q10 (CoQ 10 ; MIM# 607426) deficiencies are an emerging group of inherited mitochondrial disorders with heterogonous clinical phenotypes. Over a dozen genes are involved in the biosynthesis of CoQ 10 , and mutations in several of these are associated with human disease. However, mutations in COQ5 (MIM# 616359), catalyzing the only C-methylation in the CoQ 10 synthetic pathway, have not been implicated in human disease. Here, we report three female siblings of Iraqi-Jewish descent, who had varying degrees of cerebellar ataxia, encephalopathy, generalized tonic-clonic seizures, and cognitive disability. Whole-exome and subsequent whole-genome sequencing identified biallelic duplications in the COQ5 gene, leading to reduced levels of CoQ 10 in peripheral white blood cells of all affected individuals and reduced CoQ 10 levels in the only muscle tissue available from one affected proband. CoQ 10 supplementation led to clinical improvement and increased the concentrations of CoQ 10 in blood. This is the first report of primary CoQ 10 deficiency caused by loss of function of COQ5, with delineation of the clinical, laboratory, histological, and molecular features, and insights regarding targeted treatment with CoQ 10 supplementation., (© Published 2017. This article is a U.S. Government work and is in the public domain in the USA.)

Cellular distribution and dynamics of mitochondria are regulated by several motor proteins and a microtubule network. In neurons, mitochondrial trafficking is crucial because of high energy needs and calcium ion buffering along axons to synapses during neurotransmission. The trafficking kinesin proteins (TRAKs) are well characterized for their role in lysosomal and mitochondrial trafficking in cells, especially neurons. Using whole exome sequencing, we identified homozygous truncating variants in TRAK1 (NM&#95;001042646:c.287-2A > C), in six lethal encephalopathic patients from three unrelated families. The pathogenic variant results in aberrant splicing and significantly reduced gene expression at the RNA and protein levels. In comparison with normal cells, TRAK1-deficient fibroblasts showed irregular mitochondrial distribution, altered mitochondrial motility, reduced mitochondrial membrane potential, and diminished mitochondrial respiration. This study confirms the role of TRAK1 in mitochondrial dynamics and constitutes the first report of this gene in association with a severe neurodevelopmental disorder., (© Published by Oxford University Press on behalf of the Guarantors of Brain 2017. This work is written by US Government employees and is in the public domain in the US.)

UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase is the key enzyme of sialic acid biosynthesis in vertebrates. It catalyzes the first two steps of the cytosolic formation of CMP-N-acetylneuraminic acid from UDP-N-acetylglucosamine. In this review we give an overview of structure, biochemistry, and genetics of the bifunctional enzyme and its complex regulation. Furthermore, we will focus on diseases related to UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase.

Background: UDP-GlcNAc 2-epimerase/ManNAc 6-kinase (GNE) is a bifunctional enzyme responsible for the first committed steps in the synthesis of sialic acid, a common terminal monosaccharide in both protein and lipid glycosylation. GNE mutations are responsible for a rare autosomal recessive neuromuscular disorder, GNE myopathy (also called hereditary inclusion body myopathy). The connection between the impairment of sialic acid synthesis and muscle pathology in GNE myopathy remains poorly understood., Methods: Glycosphingolipid (GSL) analysis was performed by HPLC in multiple models of GNE myopathy, including patients' fibroblasts and plasma, control fibroblasts with inhibited GNE epimerase activity through a novel imino sugar, and tissues of Gne(M712T/M712T) knock-in mice., Results: Not only neutral GSLs, but also sialylated GSLs, were significantly increased compared to controls in all tested models of GNE myopathy. Treatment of GNE myopathy fibroblasts with N-acetylmannosamine (ManNAc), a sialic acid precursor downstream of GNE epimerase activity, ameliorated the increased total GSL concentrations., Conclusion: GNE myopathy models have increased total GSL concentrations. ManNAc supplementation results in decrease of GSL levels, linking abnormal increase of total GSLs in GNE myopathy to defects in the sialic acid biosynthetic pathway. These data advocate for further exploring GSL concentrations as an informative biomarker, not only for GNE myopathy, but also for other disorders of sialic acid metabolism.

Aim: The exact pathomechanism of GNE myopathy remains elusive, but likely involves aberrant sialylation. We explored sialylation status of blood-based glycans as potential disease markers., Methods: We employed immunoblotting, lectin histochemistry and mass spectrometry., Results: GNE myopathy muscle showed hyposialylation of predominantly O-linked glycans. The O-linked glycome of patients' plasma compared with controls showed increased amounts of desialylated Thomsen-Friedenreich (T)-antigen, and/or decreased amounts of its sialylated form, ST-antigen. Importantly, all patients had increased T/ST ratios compared with controls. These ratios were normalized in a patient treated with intravenous immunoglobulins as a source of sialic acid., Discussion:  GNE myopathy clinical trial data will reveal whether T/ST ratios correlate to muscle function. , Conclusion: Plasma T/ST ratios are a robust blood-based biomarker for GNE myopathy, and may also help explain the pathology and course of the disease.

The bifunctional enzyme UDP-GlcNAc 2-epimerase/ManNAc kinase (GNE) catalyzes the first two committed steps in sialic acid synthesis. Non-allosteric GNE gene mutations cause the muscular disorder GNE myopathy (also known as hereditary inclusion body myopathy), whose exact pathology remains unknown. Increased knowledge of GNE regulation, including isoform regulation, may help elucidate the pathology of GNE myopathy. While eight mRNA transcripts encoding human GNE isoforms are described, we only identified two mouse Gne mRNA transcripts, encoding mGne1 and mGne2, homologous to human hGNE1 and hGNE2. Orthologs of the other human isoforms were not identified in mice. mGne1 appeared as the ubiquitously expressed, major mouse isoform. The mGne2 encoding transcript is differentially expressed and may act as a tissue-specific regulator of sialylation. mGne2 expression appeared significantly increased the first 2 days of life, possibly reflecting the high sialic acid demand during this period. Tissues of the knock-in Gne p.M712T mouse model had similar mGne transcript expression levels among genotypes, indicating no effect of the mutation on mRNA expression. However, upon treatment of these mice with N-acetylmannosamine (ManNAc, a Gne substrate, sialic acid precursor, and proposed therapy for GNE myopathy), Gne transcript expression, in particular mGne2, increased significantly, likely resulting in increased Gne enzymatic activities. This dual effect of ManNAc supplementation (increased flux through the sialic acid pathway and increased Gne activity) needs to be considered when treating GNE myopathy patients with ManNAc. In addition, the existence and expression of GNE isoforms needs consideration when designing other therapeutic strategies for GNE myopathy.

GNE myopathy, previously termed hereditary inclusion body myopathy (HIBM), is an adult-onset neuromuscular disorder characterized by progressive muscle weakness. The disorder results from biallelic mutations in GNE, encoding UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase, the key enzyme of sialic acid synthesis. GNE myopathy, associated with impaired glycan sialylation, has no approved therapy. Here we test potential sialylation-increasing monosaccharides for their effectiveness in prophylaxis (at the embryonic and neonatal stages) and therapy (after the onset of symptoms) by evaluating renal and muscle hyposialylation in a knock-in mouse model (Gne p.M712T) of GNE myopathy. We demonstrate that oral mannosamine (ManN), but not sialic acid (Neu5Ac), mannose (Man), galactose (Gal), or glucosamine (GlcN), administered to pregnant female mice has a similar prophylactic effect on renal hyposialylation, pathology and neonatal survival of mutant offspring, as previously shown for N-acetylmannosamine (ManNAc) therapy. ManN may be converted to ManNAc by a direct, yet unknown, pathway, or may act through another mode of action. The other sugars (Man, Gal, GlcN) may either not cross the placental barrier (Neu5Ac) and/or may not be able to directly increase sialylation. Because GNE myopathy patients will likely require treatment in adulthood after onset of symptoms, we also administered ManNAc (1 or 2g/kg/day for 12 weeks), Neu5Ac (2 g/kg/day for 12 weeks), or ManN (2 g/kg/day for 6 weeks) in drinking water to 6 month old mutant Gne p.M712T mice. All three therapies markedly improved the muscle and renal hyposialylation, as evidenced by lectin histochemistry for overall sialylation status and immunoblotting of specific sialoproteins. These preclinical data strongly support further evaluation of oral ManNAc, Neu5Ac and ManN as therapy for GNE myopathy and conceivably for certain glomerular diseases with hyposialylation., (Published by Elsevier Inc.)

Pathological glomerular hyposialylation has been implicated in certain unexplained glomerulopathies, including minimal change nephrosis, membranous glomerulonephritis, and IgA nephropathy. We studied our previously established mouse model carrying a homozygous mutation in the key enzyme of sialic acid biosynthesis, N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase. Mutant mice died before postnatal day 3 (P3) from severe glomerulopathy with podocyte effacement and segmental glomerular basement membrane splitting due to hyposialylation. Administration of the sialic acid precursor N-acetylmannosamine (ManNAc) led to improved sialylation and survival of mutant pups beyond P3. We determined the onset of the glomerulopathy in the embryonic stage. A lectin panel, distinguishing normally sialylated from hyposialylated glycans, used WGA, SNA, PNA, Jacalin, HPA, and VVA, indicating glomerular hyposialylation of predominantly O-linked glycoproteins in mutant mice. The glomerular glycoproteins nephrin and podocalyxin were hyposialylated in this unique murine model. ManNAc treatment appeared to ameliorate the hyposialylation status of mutant mice, indicated by a lectin histochemistry pattern similar to that of wild-type mice, with improved sialylation of both nephrin and podocalyxin, as well as reduced albuminuria compared with untreated mutant mice. These findings suggest application of our lectin panel for categorizing human kidney specimens based on glomerular sialylation status. Moreover, the partial restoration of glomerular architecture in ManNAc-treated mice highlights ManNAc as a potential treatment for humans affected with disorders of glomerular hyposialylation., (Copyright © 2012 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.)

Hereditary inclusion body myopathy (HIBM) is an autosomal recessive adult-onset myopathy due to mutations in the GNE (UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase) gene. Affected patients have no therapeutic options. We have previously demonstrated in preclinical testing the ability to safely correct GNE gene function through liposomal delivery of the wild-type GNE gene. Results were verified in a single patient treated by intravenous infusion of GNE gene lipoplex. A single patient (patient 001) with severe HIBM treated with a compassionate investigational new drug received seven doses of GNE gene lipoplex via intravenous infusion at the following doses: 0.4, 0.4, 1.0, 4.0, 5.0, 6.0, and 7.0 mg of DNA. GNE transgene expression, downstream induction of sialic acid, safety, and muscle function were evaluated. Transient low-grade fever, myalgia, tachycardia, transaminase elevation, hyponatremia, and hypotension were observed after infusion of each dose of GNE gene lipoplex. Quadriceps muscle expression of the delivered GNE, plasmid, and RNA was observed 24 hr after the 5.0-mg dose and at significantly greater levels 72 hr after the 7.0-mg infusion in comparison with expression in quadriceps muscle immediately before infusion. Sialic acid-related proteins were increased and stabilization in the decline of muscle strength was observed. We conclude that clinical safety and activity have been demonstrated with intravenous infusion of GNE gene lipoplex. Further assessment will involve a phase I trial of intravenous administration of GNE gene lipoplex in individuals with less advanced HIBM with more muscle function.

UDP-GlcNAc 2-epimerase/ManNAc kinase (GNE) catalyzes the first two committed steps in sialic acid synthesis. In addition to the three previously described human GNE isoforms (hGNE1-hGNE3), our database and polymerase chain reaction analysis yielded five additional human isoforms (hGNE4-hGNE8). hGNE1 is the ubiquitously expressed major isoform, while the hGNE2-hGNE8 isoforms are differentially expressed and may act as tissue-specific regulators of sialylation. hGNE2 and hGNE7 display a 31-residue N-terminal extension compared to hGNE1. On the basis of similarities to kinases and helicases, this extension does not seem to hinder the epimerase enzymatic active site. hGNE3 and hGNE8 contain a 55-residue N-terminal deletion and a 50-residue N-terminal extension compared to hGNE1. The size and secondary structures of these fragments are similar, and modeling predicted that these modifications do not affect the overall fold compared to that of hGNE1. However, the epimerase enzymatic activity of GNE3 and GNE8 is likely absent, because the deleted fragment contains important substrate binding residues in homologous bacterial epimerases. hGNE5-hGNE8 have a 53-residue deletion, which was assigned a role in substrate (UDP-GlcNAc) binding. Deletion of this fragment likely eliminates epimerase enzymatic activity. Our findings imply that GNE is subject to evolutionary mechanisms to improve cellular functions, without increasing the number of genes. Our expression and modeling data contribute to elucidation of the complex functional and regulatory mechanisms of human GNE and may contribute to further elucidating the pathology and treatment strategies of the human GNE-opathies sialuria and hereditary inclusion body myopathy., (© 2011 American Chemical Society)

Intravenous vascular access is technically challenging in the adult mouse and even more challenging in neonatal mice. The authors describe the technique of retro-orbital injection of the venous sinus in the adult and neonatal mouse. This technique is a useful alternative to tail vein injection for the administration of non-tumorigenic compounds. The authors report that they have routinely used this technique in the adult mouse to administer volumes up to 150 μl without incident. Administration of retro-orbital injections is more challenging in neonatal mice but can reliably deliver volumes up to 10 μl.

Progressive familial intrahepatic cholestasis (PFIC) is a group of rare heterogeneous autosomal recessive disorders characterized by metabolic defects in biliary proteins involved in the formation and transfer of bile acids in the liver. The genotype-phenotype correlation is not always clear. Mutations in the ATP8B1, BSEP and MDR3 genes have been associated with PFIC1, PFIC2 and PFIC3, respectively. This study sought to characterize the molecular genetic basis for PFIC subtypes in Israel. It was conducted on 14 children with PFIC and their families; 10 with a PFIC1 or PFIC2 phenotype and 4 with a PFIC3 phenotype. Using denaturing high-performance liquid chromatography (DHPLC), five different mutations were identified in four affected families: three novel mutations in BSEP (G19R-g181c, S226L-c803t and G877R-g2755a), one novel mutation in MDR3 (IVS14+6 t/c) and one heterozygous mutation in ATP8B1 (R600W, in a family with the PFIC1/PFIC2 phenotype). The cause of PFIC was identified in 20% of the families tested. These findings indicate the probable involvement of additional genes in PFIC and the need for further studies to determine whether the abnormality lies on the RNA or protein level. A better understanding of the phenotype-genotype correlation in PFIC will lead to improved diagnoses and treatments.

The bifunctional enzyme UDP-GlcNAc 2-epimerase/ ManNAc kinase (GNE/MNK), encoded by the GNE gene, catalyzes the first two committed, rate-limiting steps in the biosynthesis of N-acetylneuraminic acid (sialic acid). GNE/MNK is feedback inhibited by binding of the downstream product, CMP-sialic acid in its allosteric site. GNE mutations can result in two human disorders, hereditary inclusion body myopathy (HIBM) or sialuria. So far, no active site geometry predictions or conformational transitions involved with function are available for mammalian GNE/MNK. The N-terminal GNE domain is homologous to various prokaryotic 2-epimerases, some of which have solved crystallographic structures. The C-terminal MNK domain belongs to the sugar kinases superfamily; its crystallographic structure is solved at 2.84 A and three-dimensional structures have also been reported for several other kinases. In this work, we employed available structural data of GNE/MNK homologs to model the active sites of human GNE/MNK and identify critical amino acid residues responsible for interactions with substrates. In addition, we modeled effects of GNE/MNK missense mutations associated with HIBM or sialuria on helix arrangement, substrate binding, and enzyme action. We found that all reported mutations are associated with the active sites or secondary structure interfaces of GNE/MNK. The Persian-Jewish HIBM founder mutation p.M712T is located at the interface alpha4alpha10 and likely affects GlcNAc, Mg2+, and ATP binding. This work contributes to further understanding of GNE/MNK function and ligand binding, which may assist future studies for therapeutic options that target misfolded GNE/MNK in HIBM and/or sialuria.

The aims of our research were to define the genotype-phenotype correlations of mutations in the phenylalanine hydroxylase (PAH) gene that cause phenylketonuria (PKU) among the Israeli population. The mutation spectrum of the PAH gene in PKU patients in Israel is described, along with a discussion on genotype-phenotype correlations. By using polymerase chain reaction/denaturing high-performance liquid chromatography (PCR/dHPLC) and DNA sequencing, we screened all exons of the PAH gene in 180 unrelated patients with four different PKU phenotypes [classic PKU, moderate PKU, mild PKU, and mild hyperphenylalaninemia (MHP)]. In 63.2% of patient genotypes, the metabolic phenotype could be predicted, though evidence is also found for both phenotypic inconsistencies among subjects with more than one type of mutation in the PAH gene. Data analysis revealed that about 25% of patients could participate in the future in (6R)-L: -erythro-5, 6, 7, 8-tetrahydrobiopterin (BH4) treatment trials according to their mutation genotypes. This study enables us to construct a national database in Israel that will serve as a valuable tool for genetic counseling and a prognostic evaluation of future cases of PKU.