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As the most frequent cause of acquired myopathy, toxic myopathies are characterised by clinicopathological features that vary depending on the mode of action of the drugs or toxins involved. Although a large number of substances can induce myotoxicity, the main culprits are statins, alcohol, and corticosteroids. A rigorous, well-organised diagnostic approach is necessary to obtain a rapid diagnosis. For early diagnosis and management, it is important for clinicians to be aware that most toxic myopathies are potentially reversible, and the goal of treatment should be to avoid serious muscle damage.
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OBJECTIVE: The objective of this study was to evaluate the implementation of NGS within the French mitochondrial network, MitoDiag, from targeted gene panels to whole exome sequencing (WES) or whole genome sequencing (WGS) focusing on mitochondrial nuclear-encoded genes. METHODS: Over 2000 patients suspected of Primary Mitochondrial Diseases (PMD) were sequenced by either targeted gene panels, WES or WGS within MitoDiag. We described the clinical, biochemical, and molecular data of 397 genetically confirmed patients, comprising 294 children and 103 adults, carrying pathogenic or likely pathogenic variants in nuclear-encoded genes. RESULTS: The cohort exhibited a large genetic heterogeneity, with the identification of 172 distinct genes and 253 novel variants. Among children, a notable prevalence of pathogenic variants in genes associated with oxidative phosphorylation (OXPHOS) functions and mitochondrial translation was observed. In adults, pathogenic variants were primarily identified in genes linked to mtDNA maintenance. Additionally, a substantial proportion of patients (54% (42/78) and 48% (13/27) in children and adults, respectively), undergoing WES or WGS testing displayed PMD mimics, representing pathologies that clinically resemble mitochondrial diseases. INTERPRETATION: We reported the largest French cohort of patients suspected of PMD with pathogenic variants in nuclear genes. We have emphasized the clinical complexity of PMD and the challenges associated with recognizing and distinguishing them from other pathologies, particularly neuromuscular disorders. We confirmed that WES/WGS, instead of panel approach, was more valuable to identify the genetic basis in patients with "possible" PMD and we provided a genetic testing flowchart to guide physicians in their diagnostic strategy.
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Enfermedades Mitocondriales , Humanos , Enfermedades Mitocondriales/genética , Enfermedades Mitocondriales/diagnóstico , Francia , Niño , Adulto , Masculino , Femenino , Adolescente , Persona de Mediana Edad , Preescolar , Estudios de Cohortes , Adulto Joven , Lactante , Secuenciación del Exoma , Anciano , Secuenciación Completa del Genoma , ADN Mitocondrial/genética , Diagnóstico DiferencialRESUMEN
Background: Mitochondrial functions are controlled by genes of both mitochondrial and nuclear DNA. Pathogenic variants affecting any of these are responsible for primary mitochondrial disorders (MIDs), which can be diagnosed during adulthood. Kidney functions are highly dependent on mitochondrial respiration. However, the prevalence of MID-associated nephropathies (MIDANs) is unknown in the adult population. We aimed to address this point and to provide a full characterization of MIDANs in this population. Methods: We retrospectively included for observational study adults (≥16 years of age) with genetically diagnosed MID between 2000 and 2020 in our tertiary care academic centre when they had a chronic kidney disease (CKD) evaluation. MIDANs were ascertained by CKD occurring in MIDs. The phenotypic, biological, histopathological and genotypic characteristics were recorded from the medical charts. Results: We included 80 MID-affected adults and ascertained MIDANs in 28/80 (35%). Kidney diseases under the care of a nephrologist occurred in only 14/28 (50%) of the adults with MIDAN. MIDANs were tubulointerstitial nephropathy in 14/28 patients (50%) and glomerular diseases in 9/28 (32.1%). In adults with MID, MIDAN was negatively associated with higher albumin levels {odds ratio [OR] 0.79 [95% confidence interval (CI) 0.67-0.95]} and vision abnormalities [OR 0.17 (95% CI 0.03-0.94)] and positively associated with hypertension [OR 4.23 (95% CI 1.04-17.17)]. Conclusion: MIDANs are frequent among adult MIDs. They are mostly represented by tubulointerstitial nephropathy or glomerular disease. Vision abnormalities, hypertension and albumin levels were independently associated with MIDANs. Our results pave the way for prospective studies investigating the prevalence of MIDANs among undetermined kidney disease populations.
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BACKGROUND: Livedoid vasculopathy (LV) is a chronic dermatosis associated with micro-thrombosis of the vessels of the dermis, leading to ischemic lesions and painful skin ulcerations of the lower limbs. This thrombosing occlusive vasculopathy, clearly distinct from 'classical vasculitis' (not related to alteration of vessel walls), may lead to peripheral neuropathy. OBJECTIVE: To clarify the main clinical, electrophysiological and pathological characteristics of peripheral neuropathy linked to LV. METHOD: We presented a series of personal cases of peripheral neuropathy due to LV. We also conducted a review of the literature (since the first description of LV in 1974) using multiple combinations of keywords from 'PubMed', 'Google Scholar' and 'ScienceDirect' databases according to the 'Preferred Reporting Items for Systematic reviews and Meta-Analyses' guidelines. RESULTS: We identified 16 patients (6 personal cases and 10 cases from the medical literature). Our personal cases were five females and one male, with a median age (at the onset of cutaneous signs of LV) of 38 (range 25-62). Several types of skin lesions of the lower limbs were observed. Median age at the onset of peripheral neuropathy symptoms was 48 years (range 29-66), with a main clinical and electrophysiological pattern of mononeuropathy multiplex. DISCUSSION: We observed a typical pattern of peripheral neuropathy, mostly mononeuropathy multiplex, whose pathophysiology might be related to occlusions of the small vessels of the nerves, as seen in the dermis. Moreover, LV may also be associated with other types of peripheral neuropathies (sometimes of autoimmune etiology) not directly related to the skin lesions. CONCLUSION: The 'ischemic form' of peripheral neuropathy linked to LV is mainly responsible for sensory disturbances (with multifocal distribution), sometimes for motor disturbances. This type of peripheral neuropathy has to be distinguished from 'classical vasculitic neuropathies' which are usually treated with antithrombotic therapies.
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Vasculopatía Livedoide , Mononeuropatías , Enfermedades del Sistema Nervioso Periférico , Vasculitis , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Mononeuropatías/complicaciones , Enfermedades del Sistema Nervioso Periférico/diagnóstico , Piel/patología , Vasculitis/complicacionesRESUMEN
Giant cell arteritis, the most frequent form of vasculitis in persons over 50 years of age, is a granulomatous chronic vasculitis involving large and medium-sized vessels, most commonly the temporal and other cranial arteries. This common, treatable condition is associated with various clinical symptoms, including neurological ones, affecting both the central and peripheral nervous systems. In this review, we discuss the cranial and extra cranial neurological complications of giant cell arteritis, to help avoid the many pitfalls in the diagnosis of giant cell arteritis.
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Arteritis de Células Gigantes , Arteritis de Células Gigantes/complicaciones , Arteritis de Células Gigantes/diagnóstico , Humanos , Persona de Mediana EdadRESUMEN
Diagnosis of myopathies is challenged by the high genetic heterogeneity and clinical overlap of the various etiologies. We previously reported a Next-Generation Sequencing strategy to identify genetic etiology in patients with undiagnosed Limb-Girdle Muscular Dystrophies, Congenital Myopathies, Congenital Muscular Dystrophies, Distal Myopathies, Myofibrillar Myopathies, and hyperCKemia or effort intolerance, using a large gene panel including genes classically associated with other entry diagnostic categories. In this study, we report the comprehensive clinical-biological strategy used to interpret NGS data in a cohort of 156 pediatric and adult patients, that included Copy Number Variants search, variants filtering and interpretation according to ACMG guidelines, segregation studies, deep phenotyping of patients and relatives, transcripts and protein studies, and multidisciplinary meetings. Genetic etiology was identified in 74 patients, a diagnostic yield (47.4%) similar to previous studies. We identified 18 patients (10%) with causative variants in different genes (ACTA1, RYR1, NEB, TTN, TRIP4, CACNA1S, FLNC, TNNT1, and PAPBN1) that resulted in milder and/or atypical phenotypes, with high intrafamilial variability in some cases. Mild phenotypes could mostly be explained by a less deleterious effect of variants on the protein. Detection of inter-individual variability and atypical phenotype-genotype associations is essential for precision medicine, patient care, and to progress in the understanding of the molecular mechanisms of myopathies.
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Genotipo , Enfermedades Musculares/patología , Fenotipo , Adulto , Niño , Estudios de Cohortes , Femenino , Secuenciación de Nucleótidos de Alto Rendimiento/métodos , Humanos , Masculino , Enfermedades Musculares/diagnóstico , Enfermedades Musculares/genéticaRESUMEN
NADH:ubiquinone oxidoreductase (respiratory complex I) plays a major role in energy metabolism by coupling electron transfer from NADH to quinone with proton translocation across the membrane. Complex I deficiencies were found to be the most common source of human mitochondrial dysfunction that manifest in a wide variety of neurodegenerative diseases. Seven subunits of human complex I are encoded by mitochondrial DNA (mtDNA) that carry an unexpectedly large number of mutations discovered in mitochondria from patients' tissues. However, whether or how these genetic aberrations affect complex I at a molecular level is unknown. Here, we used Escherichia coli as a model system to biochemically characterize two mutations that were found in mtDNA of patients. The V253AMT-ND5 mutation completely disturbed the assembly of complex I, while the mutation D199GMT-ND1 led to the assembly of a stable complex capable to catalyze redox-driven proton translocation. However, the latter mutation perturbs quinone reduction leading to a diminished activity. D199MT-ND1 is part of a cluster of charged amino acid residues that are suggested to be important for efficient coupling of quinone reduction and proton translocation. A mechanism considering the role of D199MT-ND1 for energy conservation in complex I is discussed.
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Complejo I de Transporte de Electrón/genética , Escherichia coli/crecimiento & desarrollo , Proteínas Mitocondriales/genética , Mutación , NADH Deshidrogenasa/genética , Adulto , Benzoquinonas/metabolismo , Complejo I de Transporte de Electrón/química , Complejo I de Transporte de Electrón/metabolismo , Escherichia coli/genética , Humanos , Recién Nacido , Proteínas Mitocondriales/química , Proteínas Mitocondriales/metabolismo , Modelos Moleculares , NADH Deshidrogenasa/química , NADH Deshidrogenasa/metabolismo , Operón , Plásmidos/genéticaRESUMEN
PURPOSE: Diseases caused by defects in mitochondrial DNA (mtDNA) maintenance machinery, leading to mtDNA deletions, form a specific group of disorders. However, mtDNA deletions also appear during aging, interfering with those resulting from mitochondrial disorders. METHODS: Here, using next-generation sequencing (NGS) data processed by eKLIPse and data mining, we established criteria distinguishing age-related mtDNA rearrangements from those due to mtDNA maintenance defects. MtDNA deletion profiles from muscle and urine patient samples carrying pathogenic variants in nuclear genes involved in mtDNA maintenance (n = 40) were compared with age-matched controls (n = 90). Seventeen additional patient samples were used to validate the data mining model. RESULTS: Overall, deletion number, heteroplasmy level, deletion locations, and the presence of repeats at deletion breakpoints were significantly different between patients and controls, especially in muscle samples. The deletion number was significantly relevant in adults, while breakpoint repeat lengths surrounding deletions were discriminant in young subjects. CONCLUSION: Altogether, eKLIPse analysis is a powerful tool for measuring the accumulation of mtDNA deletions between patients of different ages, as well as in prioritizing novel variants in genes involved in mtDNA stability.
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Genoma Mitocondrial , Enfermedades Mitocondriales , Adulto , ADN Mitocondrial/genética , Genoma Mitocondrial/genética , Secuenciación de Nucleótidos de Alto Rendimiento , Humanos , Mitocondrias/genética , Enfermedades Mitocondriales/diagnóstico , Enfermedades Mitocondriales/genética , Eliminación de Secuencia/genéticaRESUMEN
With the exception of infantile spinal muscular atrophy (SMA) and congenital myotonic dystrophy 1 (DM1), congenital myopathies and muscular dystrophies with neonatal respiratory distress pose diagnostic challenges. Next-generation sequencing (NGS) provides hope for the diagnosis of these rare diseases. We evaluated the efficiency of next-generation sequencing (NGS) in ventilated newborns with peripheral hypotonia. We compared the results of our previous study in a cohort of 19 patients analysed by Sanger sequencing from 2007 to 2012, with a diagnostic yield of 26% (5/19), and those of a new retrospective study in 28 patients from 2007 to 2018 diagnosed using MyoPanel, a neuromuscular disease panel, with a diagnostic yield of 43% (12/28 patients). Pathogenic variants were found in five genes: ACTA1 (n = 4 patients), RYR1 (n = 2), CACNA1S (n = 1), NEB (n = 3), and MTM1 (n = 2). Myopanel increased the diagnosis of congenital neuromuscular diseases, but more than half the patients remained undiagnosed. Whole exome sequencing did not seem to fully respond to this diagnostic limitation. Therefore, explorations with whole genome sequencing will be the next step.
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Secuenciación de Nucleótidos de Alto Rendimiento/métodos , Enfermedades Neuromusculares/diagnóstico , Síndrome de Dificultad Respiratoria del Recién Nacido/diagnóstico , Síndrome de Dificultad Respiratoria del Recién Nacido/etiología , Estudios de Cohortes , Femenino , Humanos , Lactante , Recién Nacido , Masculino , Enfermedades Neuromusculares/genética , Estudios RetrospectivosRESUMEN
Bi-allelic pathogenic variants in genes of the EIF2B family are responsible for Childhood Ataxia with Central nervous system Hypomyelination/Vanishing White Matter disease, a progressive neurodegenerative disorder of the central white matter. Only seven molecularly proven cases with antenatal onset have been reported so far. We report for the first time the neuropathological findings obtained from two foetuses harbouring deleterious variants in the EIF2B5 gene who presented in utero growth retardation and microcephaly with simplified gyral pattern that led to a medical termination of the pregnancy at 27 and 32 weeks of gestation. Neuropathological examination confirmed microcephaly with delayed gyration, periventricular pseudo-cysts and severe cerebellar hypoplasia. Histologically, the cerebellar cortex was immature, the dentate nuclei were fragmented and myelin stains revealed almost no myelination of the infratentorial structures. Bergmann glia was virtually absent associated to a drastic decreased number of mature astrocytes in the cerebellar white matter, multiple nestin-positive immature astrocytes as well as increased numbers of PDGRFα-positive oligodendrocyte precursors. Whole exome sequencing performed in the two foetuses and their parents allowed the identification of two EIF2B5 compound heterozygous variants in the two foetuses: c.468C > G p.Ile156Met and c.1165G > A p.Val389Met, the parents being heterozygous carriers. These variants are absent in the genome Aggregation Database (gnomAD r2.0.2). Contrary to the variant Ile156Met already described in a patient with CACH syndrome, the variant p.Val389Met is novel and predicted to be deleterious using several softwares. Neuropathological findings further expand the phenotypic spectrum of the disease that very likely occurs during early gestation and may manifest from the second half of pregnancy by a severe impairment of cerebral and cerebellar development.
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Factor 2B Eucariótico de Iniciación/genética , Leucoencefalopatías/genética , Leucoencefalopatías/patología , Femenino , Feto , Humanos , Masculino , Embarazo , HermanosRESUMEN
Kidney is a highly adenosine triphosphate dependent organ in human body. Healthy and functional mitochondria are essential for normal kidney function. Clinical and genetic variability are the hallmarks of mitochondrial disorders. We report here the involvement of two MT-ND5 pathogenic variants encoding for ND5 subunit of respiratory chain complex I, the m.13513G>A and the m.13514A>G, in adult-onset kidney disease in three unrelated patients. The first patient had myopathy encephalopathy lactic acidosis and stroke syndrome, left ventricular hypertrophy with Wolff-Parkinson-White syndrome and tubulo-interstitial kidney disease. The second presented Leber hereditary optic neuropathy associated with tubulo-interstitial kidney disease. The third presented with an isolated chronic tubulo-interstitial kidney disease. These mutations have never been associated with adulthood mitochondrial nephropathy. These case reports highlight the importance to consider mitochondrial dysfunction in tubulo-interstitial kidney disease.
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Complejo I de Transporte de Electrón/genética , Riñón/metabolismo , Proteínas Mitocondriales/genética , Nefritis Intersticial/genética , Síndrome de Wolff-Parkinson-White/genética , Adulto , ADN Mitocondrial/genética , Femenino , Humanos , Riñón/patología , Masculino , Persona de Mediana Edad , Mitocondrias/genética , Mutación/genética , Nefritis Intersticial/patología , Fenotipo , Síndrome de Wolff-Parkinson-White/patologíaRESUMEN
Myopathies and muscular dystrophies (M-MDs) are genetically heterogeneous diseases, with >100 identified genes, including the giant and complex titin (TTN) and nebulin (NEB) genes. Next-generation sequencing technology revolutionized M-MD diagnosis and revealed high frequency of TTN and NEB variants. We developed a next-generation sequencing diagnostic strategy targeted to the coding sequences of 135 M-MD genes. Comparison of two targeted capture technologies (SeqCap EZ Choice library capture kit and Nextera Rapid Capture Custom Enrichment kit) and of two whole-exome sequencing kits (SureSelect V5 and TruSeq RapidExome capture) revealed best coverage with the SeqCap EZ Choice protocol. A marked decrease in coverage was observed with the other kits, affecting mostly the first exons of genes and the repeated regions of TTN and NEB. Bioinformatics analysis strategy was fine-tuned to achieve optimal detection of variants, including small insertions/deletions (INDELs) and copy number variants (CNVs). Analysis of a cohort of 128 patients allowed the detection of 52 substitutions, 13 INDELs (including a trinucleotide repeat expansion), and 3 CNVs. Two INDELs were localized in the repeated regions of NEB, suggesting that these mutations may be frequent but underestimated. A large deletion was also identified in TTN that is, to our knowledge, the first published CNV in this gene.
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Conectina/genética , Secuenciación de Nucleótidos de Alto Rendimiento/métodos , Proteínas Musculares/genética , Distrofias Musculares/diagnóstico , Distrofias Musculares/genética , Biología Computacional , ADN/genética , Variaciones en el Número de Copia de ADN/genética , Exones/genética , Heterocigoto , Humanos , Mutación INDEL/genética , Reproducibilidad de los ResultadosRESUMEN
Among the mechanisms underlying the development of L-dopa-induced dyskinesia (LID) in Parkinson's disease, complex alterations in dopamine signaling in D1 receptor (D1R)-expressing medium spiny striatal neurons have been unraveled such as, but not limited to, dysregulation of D1R expression, lateral diffusion, intraneuronal trafficking, subcellular localization and desensitization, leading to a pathological anchorage of D1R at the plasma membrane. Such anchorage is partly due to a decreased proteasomal activity that is specific of the L-dopa-exposed dopamine-depleted striatum, results from D1R activation and feeds-back the D1R exaggerated cell surface abundance. The precise mechanisms by which L-dopa affects striatal proteasome activity remained however unknown. We here show, in a series of in vitro ex vivo and in vivo models, that such rapid modulation of striatal proteasome activity intervenes through D1R-mediated disassembly of the 26S proteasome rather than change in transcription or translation of proteasome or proteasome subunits intraneuronal relocalization.
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Cuerpo Estriado/enzimología , Trastornos Parkinsonianos/metabolismo , Complejo de la Endopetidasa Proteasomal/metabolismo , Receptores de Dopamina D1/metabolismo , Animales , Benzazepinas/farmacología , Células Cultivadas , Cuerpo Estriado/efectos de los fármacos , Cuerpo Estriado/metabolismo , Agonistas de Dopamina/farmacología , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Neuronas/efectos de los fármacos , Neuronas/metabolismo , Trastornos Parkinsonianos/enzimología , Complejo de la Endopetidasa Proteasomal/efectos de los fármacos , Ratas Sprague-DawleyRESUMEN
Regulators of G-protein signalling (RGS) proteins are implicated in striatal G-protein coupled receptor (GPCR) sensitisation in the pathophysiology of l-DOPA-induced abnormal involuntary movements (AIMs), also known as dyskinesia (LID), in Parkinson's disease (PD). In this study, we investigated RGS protein subtype 4 in the expression of AIMs in the unilateral 6-hydroxydopamine (6-OHDA)-lesioned rat model of LID. The effects of RGS4 antisense brain infusion on the behavioural and molecular correlates of l-DOPA priming in 6-OHDA-lesioned rats were assessed. In situ hybridisation revealed that repeated l-DOPA/benserazide treatment caused an elevation of RGS4 mRNA levels in the striatum, predominantly in the lateral regions. The increased expression of RGS4 mRNA in the rostral striatum was found to positively correlate with the behavioural (AIM scores) and molecular (pre-proenkephalin B, PPE-B expression) markers of LID. We found that suppressing the elevation of RGS4 mRNA in the striatum by continuous infusion of RGS4 antisense oligonucleotides, via implanted osmotic mini-pumps, during l-DOPA priming, reduced the induction of AIMs. Moreover, ex vivo analyses of the rostral dorsolateral striatum showed that RGS4 antisense infusion attenuated l-DOPA-induced elevations of PPE-B mRNA and dopamine-stimulated [(35)S]GTPγS binding, a marker used for measuring dopamine receptor super-sensitivity. Taken together, these data suggest that (i) RGS4 proteins play an important pathophysiological role in the development and expression of LID and (ii) suppressing the elevation of RGS4 mRNA levels in l-DOPA priming attenuates the associated pathological changes in LID, dampening its physiological expression. Thus, modulating RGS4 proteins could prove beneficial in the treatment of dyskinesia in PD.
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Antiparkinsonianos/efectos adversos , Cuerpo Estriado/fisiopatología , Discinesia Inducida por Medicamentos/fisiopatología , Levodopa/efectos adversos , Trastornos Parkinsonianos/fisiopatología , Proteínas RGS/metabolismo , Animales , Antiparkinsonianos/farmacología , Células Cultivadas , Cuerpo Estriado/efectos de los fármacos , Discinesia Inducida por Medicamentos/terapia , Encefalinas/metabolismo , Lateralidad Funcional , Expresión Génica/efectos de los fármacos , Terapia Genética , Levodopa/farmacología , Masculino , Oligonucleótidos Antisentido/administración & dosificación , Oxidopamina , Trastornos Parkinsonianos/tratamiento farmacológico , Precursores de Proteínas/metabolismo , Proteínas RGS/genética , ARN Mensajero/metabolismo , Ratas Sprague-Dawley , Regulación hacia Arriba/efectos de los fármacosRESUMEN
Intracellular protein aggregates are common pathological hallmarks of many neurodegenerative disorders, and a defect in axonal transport is also incriminated. Here, we studied intra-axonal abnormal protein aggregation and axonopathy by using immunohistochemistry and electron microscopy on peripheral nerve biopsies from 12 patients with chronic axonal peripheral neuropathy (PN) of unknown etiology. Among these patients, three had idiopathic Parkinson's disease (PD). Intra-axonal ubiquitin aggregates were more numerous in the patients with PD. Intra-axonal aggregates of tau AT8 were found in five patients without PD. Phosphorylated α-synuclein aggregation was absent in all cases, while intra-axonal colocalization of 14-3-3 ß and ubiquitin was observed in two PD cases. Electron microscopy revealed enlarged axons crowded with organelles in six cases, including the three patients with PD, thus attesting a slowing of the axoplasmic flux. The number of ubiquitin aggregates was correlated with features of reduced axonal flux, while no such correlation was found for tau and 14-3-3 ß. Age did not correlate with the number of tau, ubiquitin, and 14-3-3 aggregates. Thus, both ubiquitin and/or abnormal tau intra-axonal aggregates may be found in chronic axonal PN. Ubiquitin aggregates might reduce the axonal flux or result from a disease producing slowing of axonal transport.
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Axones/metabolismo , Proteínas del Tejido Nervioso/metabolismo , Nervios Periféricos/metabolismo , alfa-Sinucleína/metabolismo , Proteínas 14-3-3/metabolismo , Anciano , Anciano de 80 o más Años , Axones/patología , Electromiografía , Femenino , Humanos , Masculino , Persona de Mediana Edad , Enfermedad de Parkinson/patología , Nervios Periféricos/patología , Enfermedades del Sistema Nervioso Periférico/patologíaRESUMEN
The development of right heart failure (RHF) is characterized by alterations of right ventricle (RV) structure and function, but the mechanisms of RHF remain still unknown. Thus, understanding the RHF is essential for improved therapies. Therefore, identification by quantitative proteomics of targets specific to RHF may have therapeutic benefits to identify novel potential therapeutic targets. The objective of this study was to analyze the molecular mechanisms changing RV function in the diseased RHF and thus, to identify novel potential therapeutic targets. For this, we have performed differential proteomic analysis of whole RV proteins using two experimental rat models of RHF. Differential protein expression was observed for hundred twenty six RV proteins including proteins involved in structural constituent of cytoskeleton, motor activity, structural molecule activity, cytoskeleton protein binding and microtubule binding. Interestingly, further analysis of down-regulated proteins, reveals that both protein and gene expressions of proteasome subunits were drastically decreased in RHF, which was accompanied by an increase of ubiquitinated proteins. Interestingly, the proteasomal activities chymotrypsin and caspase-like were decreased whereas trypsin-like activity was maintained. In conclusion, this study revealed the involvement of ubiquitin-proteasome system (UPS) in RHF. Three deregulated mechanisms were discovered: (1) decreased gene and protein expressions of proteasome subunits, (2) decreased specific activity of proteasome; and (3) a specific accumulation of ubiquitinated proteins. This modulation of UPS of RV may provide a novel therapeutic avenue for restoration of cardiac function in the diseased RHF.
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Insuficiencia Cardíaca/genética , Ventrículos Cardíacos/metabolismo , Hipoxia/genética , Complejo de la Endopetidasa Proteasomal/química , Proteoma/genética , Disfunción Ventricular Derecha/genética , Animales , Perfilación de la Expresión Génica , Regulación de la Expresión Génica , Insuficiencia Cardíaca/inducido químicamente , Insuficiencia Cardíaca/metabolismo , Insuficiencia Cardíaca/patología , Ventrículos Cardíacos/patología , Hipoxia/metabolismo , Hipoxia/patología , Masculino , Monocrotalina , Complejo de la Endopetidasa Proteasomal/genética , Complejo de la Endopetidasa Proteasomal/metabolismo , Proteolisis , Proteoma/metabolismo , Ratas , Ratas Wistar , Transducción de Señal , Ubiquitinación , Disfunción Ventricular Derecha/inducido químicamente , Disfunción Ventricular Derecha/metabolismo , Disfunción Ventricular Derecha/patologíaRESUMEN
L-DOPA-induced dyskinesia (LID), a detrimental consequence of dopamine replacement therapy for Parkinson's disease, is associated with an alteration in dopamine D1 receptor (D1R) and glutamate receptor interactions. We hypothesized that the synaptic scaffolding protein PSD-95 plays a pivotal role in this process, as it interacts with D1R, regulates its trafficking and function, and is overexpressed in LID. Here, we demonstrate in rat and macaque models that disrupting the interaction between D1R and PSD-95 in the striatum reduces LID development and severity. Single quantum dot imaging revealed that this benefit was achieved primarily by destabilizing D1R localization, via increased lateral diffusion followed by increased internalization and diminished surface expression. These findings indicate that altering D1R trafficking via synapse-associated scaffolding proteins may be useful in the treatment of dyskinesia in Parkinson's patients.
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Cuerpo Estriado/metabolismo , Discinesia Inducida por Medicamentos/metabolismo , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Levodopa/efectos adversos , Proteínas de la Membrana/metabolismo , Receptores de Dopamina D1/metabolismo , Sinapsis/metabolismo , Animales , Cuerpo Estriado/patología , Homólogo 4 de la Proteína Discs Large , Discinesia Inducida por Medicamentos/genética , Discinesia Inducida por Medicamentos/patología , Células HEK293 , Humanos , Péptidos y Proteínas de Señalización Intracelular/genética , Levodopa/farmacología , Macaca , Masculino , Proteínas de la Membrana/genética , Enfermedad de Parkinson/genética , Enfermedad de Parkinson/metabolismo , Enfermedad de Parkinson/patología , Enfermedad de Parkinson/terapia , Transporte de Proteínas/efectos de los fármacos , Ratas , Ratas Sprague-Dawley , Receptores de Dopamina D1/genética , Sinapsis/genéticaRESUMEN
Aberrant membrane localization of dopamine D(1) receptor (D1R) is associated with L-DOPA-induced dyskinesia (LID), a major complication of L-DOPA treatment in Parkinson's disease (PD). Since the proteasome plays a central role in modulating neuronal response through regulation of neurotransmitter receptor intraneuronal fate, we hypothesized that the ubiquitine-proteasome proteolytic pathway could be impaired in LID. Those LIDs are actually associated with a striatum-specific decrease in proteasome catalytic activity and accumulation of polyubiquitinated proteins in experimental rodent and monkey parkinsonism. We then demonstrated that such decreased proteasome catalytic activity (1) results from D1R activation and (2) feed-back the D1R abnormal trafficking, i.e., its exaggerated cell surface abundance. We further showed that the genetic invalidation of the E3 ubiquitin-protein ligase parkin PD gene leads to exaggerated abnormal involuntary movements compared with wild-type mice. We thus established in an unprecedented series of experimental models that impairment of the ubiquitine-proteasome system at specific nodes (E3 ligase parkin, polyubiquitination, proteasome catalytic activity) leads to the same phenomenon, i.e., aberrant behavioral response to dopamine replacement therapy in PD, highlighting the intimate interplay between dopamine receptor and proteasome activity in a nondegenerative context.
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Discinesia Inducida por Medicamentos/metabolismo , Levodopa/toxicidad , Trastornos Parkinsonianos/tratamiento farmacológico , Trastornos Parkinsonianos/metabolismo , Complejo de la Endopetidasa Proteasomal/metabolismo , Inhibidores de Proteasoma , Receptores de Dopamina D1/agonistas , Animales , Modelos Animales de Enfermedad , Agonistas de Dopamina/toxicidad , Discinesia Inducida por Medicamentos/fisiopatología , Femenino , Macaca mulatta , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Técnicas de Cultivo de Órganos , Trastornos Parkinsonianos/enzimología , Ratas , Ratas Sprague-Dawley , Receptores de Dopamina D1/fisiologíaRESUMEN
Hereditary spastic paraplegias (HSP) constitute a heterogeneous group of neurodegenerative disorders characterized at least by slowly progressive spasticity of the lower limbs. Mutations in REEP1 were recently associated with a pure dominant HSP, SPG31. We sequenced all exons of REEP1 and searched for rearrangements by multiplex ligation-dependent probe amplification (MLPA) in a large panel of 175 unrelated HSP index patients from kindreds with dominant inheritance (AD-HSP), with either pure (n = 102) or complicated (n = 73) forms of the disease, after exclusion of other known HSP genes. We identified 12 different heterozygous mutations, including two exon deletions, associated with either a pure or a complex phenotype. The overall mutation rate in our clinically heterogeneous sample was 4.5% in French families with AD-HSP. The phenotype was restricted to pyramidal signs in the lower limbs in most patients but nine had a complex phenotype associating axonal peripheral neuropathy (= 5/11 patients) including a Silver-like syndrome in one patient, and less frequently cerebellar ataxia, tremor, dementia. Interestingly, we evidenced abnormal mitochondrial network organization in fibroblasts of one patient in addition to defective mitochondrial energy production in both fibroblasts and muscle, but whether these anomalies are directly or indirectly related to the mutations remains uncertain.