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1.
Am J Hum Genet ; 107(5): 977-988, 2020 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-33058759

RESUMO

PRKACA and PRKACB code for two catalytic subunits (Cα and Cß) of cAMP-dependent protein kinase (PKA), a pleiotropic holoenzyme that regulates numerous fundamental biological processes such as metabolism, development, memory, and immune response. We report seven unrelated individuals presenting with a multiple congenital malformation syndrome in whom we identified heterozygous germline or mosaic missense variants in PRKACA or PRKACB. Three affected individuals were found with the same PRKACA variant, and the other four had different PRKACB mutations. In most cases, the mutations arose de novo, and two individuals had offspring with the same condition. Nearly all affected individuals and their affected offspring shared an atrioventricular septal defect or a common atrium along with postaxial polydactyly. Additional features included skeletal abnormalities and ectodermal defects of variable severity in five individuals, cognitive deficit in two individuals, and various unusual tumors in one individual. We investigated the structural and functional consequences of the variants identified in PRKACA and PRKACB through the use of several computational and experimental approaches, and we found that they lead to PKA holoenzymes which are more sensitive to activation by cAMP than are the wild-type proteins. Furthermore, expression of PRKACA or PRKACB variants detected in the affected individuals inhibited hedgehog signaling in NIH 3T3 fibroblasts, thereby providing an underlying mechanism for the developmental defects observed in these cases. Our findings highlight the importance of both Cα and Cß subunits of PKA during human development.

2.
J Med Genet ; 2020 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-32820033

RESUMO

OBJECTIVE: To determine the potential disease association between variants in LMBRD2 and complex multisystem neurological and developmental delay phenotypes. METHODS: Here we describe a series of de novo missense variants in LMBRD2 in 10 unrelated individuals with overlapping features. Exome sequencing or genome sequencing was performed on all individuals, and the cohort was assembled through GeneMatcher. RESULTS: LMBRD2 encodes an evolutionary ancient and widely expressed transmembrane protein with no known disease association, although two paralogues are involved in developmental and metabolic disorders. Exome or genome sequencing revealed rare de novo LMBRD2 missense variants in 10 individuals with developmental delay, intellectual disability, thin corpus callosum, microcephaly and seizures. We identified five unique variants and two recurrent variants, c.1448G>A (p.Arg483His) in three cases and c.367T>C (p.Trp123Arg) in two cases. All variants are absent from population allele frequency databases, and most are predicted to be deleterious by multiple in silico damage-prediction algorithms. CONCLUSION: These findings indicate that rare de novo variants in LMBRD2 can lead to a previously unrecognised early-onset neurodevelopmental disorder. Further investigation of individuals harbouring LMBRD2 variants may lead to a better understanding of the function of this ubiquitously expressed gene.

3.
Trends Mol Med ; 26(9): 799-800, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32709506

RESUMO

Desdín-Micó et al. have shown that Tfam specific knockout in mouse T cells disrupts mitochondrial genome integrity and induces a burst of inflammatory cytokines and tumor necrosis factor (TNF)-α production, resulting in increased senescence, neuromuscular and vascular dysfunction, and molecular features that recapitulate premature aging. Interestingly, treatment with nicotinamide riboside (NR) alleviates this phenotype by reducing senescence and systemic inflammation.


Assuntos
Senilidade Prematura , Multimorbidade , Senilidade Prematura/genética , Animais , Humanos , Inflamação , Camundongos , Mitocôndrias , Linfócitos T
4.
Eur J Med Genet ; 63(10): 104004, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32688057

RESUMO

De novo pathogenic variants in the GATAD2B gene have been associated with a syndromic neurodevelopmental disorder (GAND) characterized by severe intellectual disability (ID), impaired speech, childhood hypotonia, and dysmorphic features. Since its first description in 2013, nine patients have been reported in case reports and a series of 50 patients was recently published, which is consistent with the relative frequency of GATAD2B pathogenic variants in public databases. We report the detailed phenotype of 19 patients from various ethnic backgrounds with confirmed pathogenic GATAD2B variants including intragenic deletions. All individuals presented developmental delay with a median age of 2.5 years for independent walking and of 3 years for first spoken words. GATAD2B variant carriers showed very little subsequent speech progress, two patients over 30 years of age remaining non-verbal. ID was mostly moderate to severe, with one profound and one mild case, which shows a wider spectrum of disease severity than previously reported. We confirm macrocephaly as a major feature in GAND (53%). Most common dysmorphic features included broad forehead, deeply set eyes, hypertelorism, wide nasal base, and pointed chin. Conversely, prenatal abnormalities, non-cerebral malformations, epilepsy, and autistic behavior were uncommon. Other features included feeding difficulties, behavioral abnormalities, and unspecific abnormalities on brain MRI. Improving our knowledge of the clinical phenotype is essential for correct interpretation of the molecular results and accurate patient management.

5.
Horm Res Paediatr ; 93(1): 30-39, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32454486

RESUMO

BACKGROUND: FOXL2 is the gene involved in blepharophimosis, ptosis, and epicanthus inversus syndrome (BPES). There have been few single case reports of growth hormone deficiency (GHD) with this syndrome, and Foxl2 is known to be involved in pituitary development in mice. Our aim was to analyze the prevalence of FOXL2 gene alteration in a series of patients with congenital hypopituitarism and eyelid anomalies. METHODS: FOXL2 was analyzed in 10 patients with hypopituitarism (ranging from isolated GHD to complete pituitary hormone deficiency) and eyelid anomalies (typical BPES in 4 patients and milder anomalies in 6 patients). In patients with an FOXL2 mutation, we ruled out other possible molecular explanations by analyzing a panel of 20 genes known to be associated with hypopituitarism, and a candidate gene approach was used for patients without an FOXL2mutation. RESULTS: Three patients had an FOXL2mutation. All 3 had typical BPES. Their pituitary phenotype varied from GHD to complete pituitary hormone deficiency and their pituitary morphology ranged from normal to an interrupted pituitary stalk. No mutations were found in genes previously associated with hypopituitarism. CONCLUSION: Our study shows that some patients with BPES have hypopituitarism with no molecular explanation other than FOXL2 mutation. This points toward an involvement of FOXL2 in human pituitary development.

6.
Mol Biol Rep ; 47(5): 3779-3787, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32319008

RESUMO

Mitochondrial diseases are a clinically heterogeneous group of multisystemic disorders that arise as a result of various mitochondrial dysfunctions. Autosomal recessive aARS deficiencies represent a rapidly growing group of severe rare inherited mitochondrial diseases, involving multiple organs, and currently without curative option. They might be related to defects of mitochondrial aminoacyl t-RNA synthetases (mtARS) that are ubiquitous enzymes involved in mitochondrial aminoacylation and the translation process. Here, using NGS analysis of 281 nuclear genes encoding mitochondrial proteins, we identified 4 variants in different mtARS in three patients from unrelated Tunisian families, with clinical features of mitochondrial disorders. Two homozygous variants were found in KARS (c.683C>T) and AARS2 (c.1150-4C>G), respectively in two patients, while two heterozygous variants in EARS2 (c.486-7C>G) and DARS2 (c.1456C>T) were concomitantly found in the third patient. Bio-informatics investigations predicted their pathogenicity and deleterious effects on pre-mRNA splicing and on protein stability. Thus, our results suggest that mtARS mutations are common in Tunisian patients with mitochondrial diseases.

7.
Hum Mol Genet ; 29(8): 1319-1329, 2020 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-32202296

RESUMO

Interpretation of variants of uncertain significance is an actual major challenge. We addressed this question on a set of OPA1 missense variants responsible for variable severity of neurological impairments. We used targeted metabolomics to explore the different signatures of OPA1 variants expressed in Opa1 deleted mouse embryonic fibroblasts (Opa1-/- MEFs), grown under selective conditions. Multivariate analyses of data discriminated Opa1+/+ from Opa1-/- MEFs metabolic signatures and classified OPA1 variants according to their in vitro severity. Indeed, the mild p.I382M hypomorphic variant was segregating close to the wild-type allele, while the most severe p.R445H variant was close to Opa1-/- MEFs, and the p.D603H and p.G439V alleles, responsible for isolated and syndromic presentations, respectively, were intermediary between the p.I382M and the p.R445H variants. The most discriminant metabolic features were hydroxyproline, the spermine/spermidine ratio, amino acid pool and several phospholipids, emphasizing proteostasis, endoplasmic reticulum (ER) stress and phospholipid remodeling as the main mechanisms ranking OPA1 allele impacts on metabolism. These results demonstrate the high resolving power of metabolomics in hierarchizing OPA1 missense mutations by their in vitro severity, fitting clinical expressivity. This suggests that our methodological approach can be used to discriminate the pathological significance of variants in genes responsible for other rare metabolic diseases and may be instrumental to select possible compounds eligible for supplementation treatment.

8.
Clin Genet ; 97(5): 723-730, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-31898322

RESUMO

Disease-causing variants in TGFB3 cause an autosomal dominant connective tissue disorder which is hard to phenotypically delineate because of the small number of identified cases. The purpose of this retrospective cross-sectional multicenter study is to elucidate the genotype and phenotype in an international cohort of TGFB3 patients. Eleven (eight novel) TGFB3 disease-causing variants were identified in 32 patients (17 families). Aortic root dilatation and mitral valve disease represented the most common cardiovascular findings, reported in 29% and 32% of patients, respectively. Dissection involving distal aortic segments occurred in two patients at age 50 and 52 years. A high frequency of systemic features (65% high-arched palate, 63% arachnodactyly, 57% pectus deformity, 52% joint hypermobility) was observed. In familial cases, incomplete penetrance and variable clinical expressivity were noted. Our cohort included the first described homozygous patient, who presented with a more severe phenotype compared to her heterozygous relatives. In conclusion, TGFB3 variants were associated with a high percentage of systemic features and aortic disease (dilatation/dissection) in 35% of patients. No deaths occurred from cardiovascular events or pregnancy-related complications. Nevertheless, homozygosity may be driving a more severe phenotype.

9.
Hum Genet ; 139(4): 461-472, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31980905

RESUMO

SKI pathogenic variations are associated with Shprintzen-Goldberg Syndrome (SGS), a rare systemic connective tissue disorder characterized by craniofacial, skeletal and cardiovascular features. So far, the clinical description, including intellectual disability, has been relatively homogeneous, and the known pathogenic variations were located in two different hotspots of the SKI gene. In the course of diagnosing Marfan syndrome and related disorders, we identified nine sporadic probands (aged 2-47 years) carrying three different likely pathogenic or pathogenic variants in the SKI gene affecting the same amino acid (Thr180). Seven of these molecular events were confirmed de novo. All probands displayed a milder morphological phenotype with a marfanoid habitus that did not initially lead to a clinical diagnosis of SGS. Only three of them had learning disorders, and none had intellectual disability. Six out of nine presented thoracic aortic aneurysm, which led to preventive surgery in the oldest case. This report extends the phenotypic spectrum of variants identified in the SKI gene. We describe a new mutational hotspot associated with a marfanoid syndrome with no intellectual disability. Cardiovascular involvement was confirmed in a significant number of cases, highlighting the importance of accurately diagnosing SGS and ensuring appropriate medical treatment and follow-up.


Assuntos
Aracnodactilia , Craniossinostoses , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Síndrome de Marfan , Mutação , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas/metabolismo , Adolescente , Adulto , Aracnodactilia/diagnóstico , Aracnodactilia/genética , Aracnodactilia/metabolismo , Criança , Pré-Escolar , Craniossinostoses/diagnóstico , Craniossinostoses/genética , Craniossinostoses/metabolismo , Feminino , Humanos , Masculino , Síndrome de Marfan/diagnóstico , Síndrome de Marfan/genética , Síndrome de Marfan/metabolismo , Pessoa de Meia-Idade , Patologia Molecular
10.
Am J Med Genet A ; 182(3): 565-569, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31793730

RESUMO

RING Finger Protein 113 A (RNF113A, MIM 300951) is a highly conserved gene located on chromosome Xq24-q25, encoding a protein containing two conserved zinc finger domains involved in DNA alkylation repair and premessenger RNA splicing. To date, only one pathogenic variant of RNF113A, namely c.901C>T; p.Gln301Ter, has been reported in humans by Tarpey et al. in 2009. Thereafter, Corbett et al. stated that this variant was responsible for an X-linked form of nonphotosensitive trichothiodystrophy associated with profound intellectual disability, microcephaly, partial corpus callosum agenesis, microphallus, and absent or rudimentary testes. This variant was then shown to alter DNA alkylation repair, providing an additional argument supporting its pathogenicity and important clues about the underlying pathophysiology of nonphotosensitive trichothiodystrophy. Using exome sequencing, we identified exactly the same RNF113A variant in two fetuses affected with abnormalities similar to those previously reported by Corbett et al. To our knowledge, this is the second report of a RNF113A pathogenic variant in humans.

11.
Neurocase ; 26(1): 36-41, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31771445

RESUMO

Huntington's disease (HD) is a devastating illness, associated with progressive motor, behavioral and cognitive dysfunctions. However, some studies emphasized that social cognition impairment could occur prior to the onset of these other symptoms. Here, we report the case of a 47 years old patient with early manifest HD, whose complaint was mainly related to the behavioral sphere. He exhibited a significant impairment of Theory of Mind abilities as well as behavioral, and discrete motor symptoms without noticeable cognitive decline. This case study suggests that social cognition impairments and behavioral changes could be in some cases a feature of the disease and may represent a major disability, in early stages of manifest HD.

12.
Genet Med ; 22(3): 538-546, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31723249

RESUMO

PURPOSE: Intellectual disability (ID) and autism spectrum disorder (ASD) are genetically heterogeneous neurodevelopmental disorders. We sought to delineate the clinical, molecular, and neuroimaging spectrum of a novel neurodevelopmental disorder caused by variants in the zinc finger protein 292 gene (ZNF292). METHODS: We ascertained a cohort of 28 families with ID due to putatively pathogenic ZNF292 variants that were identified via targeted and exome sequencing. Available data were analyzed to characterize the canonical phenotype and examine genotype-phenotype relationships. RESULTS: Probands presented with ID as well as a spectrum of neurodevelopmental features including ASD, among others. All ZNF292 variants were de novo, except in one family with dominant inheritance. ZNF292 encodes a highly conserved zinc finger protein that acts as a transcription factor and is highly expressed in the developing human brain supporting its critical role in neurodevelopment. CONCLUSION: De novo and dominantly inherited variants in ZNF292 are associated with a range of neurodevelopmental features including ID and ASD. The clinical spectrum is broad, and most individuals present with mild to moderate ID with or without other syndromic features. Our results suggest that variants in ZNF292 are likely a recurrent cause of a neurodevelopmental disorder manifesting as ID with or without ASD.

13.
Prog Neurobiol ; 184: 101698, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31557505

RESUMO

The development of personalized medicine according to gender calls for the integration of sexual dimorphism in pre-clinical models of diseases. Although sexual dimorphism in the brain of the mouse has been the subject of several behavioral, neuroimaging and experimental studies, very few have characterized the bases of sexual dimorphism in the brain on the omics scale. In particular, physiological variations in metabolomic and lipidomic terms related to gender have not been mapped in the brain. We carried out a metabolomic analysis, targeting 188 metabolites representative of various cellular structures and metabolisms, in three brain regions: frontal cortex, brain stem and cerebellum, in 3-month-old C57BL-6 J male (n = 20) vs. female (n = 20) mice. Our results demonstrate the existence of sexual dimorphism in the whole brain as well as in separate brain regions. Half of the 129 accurately measured metabolites were involved in the sexual dimorphism of the murine brain, but only 8% of those (hydroxyproline, creatinine, hexoses, tryptophan, threonine and lysoPC.a.C18.2) were involved in common in the three cerebral regions, while 71%, including phosphatidylcholines, lysophosphatidylcholines, sphingomyelins, acylcarnitines, amino acids, biogenic amines, and polyamines, were specific to only one region of the brain, underscoring the highly regional specificity of cerebral sexual dimorphism in mice.

14.
Exp Neurol ; 323: 113069, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31655048

RESUMO

Charcot-Marie-Tooth (CMT) disease is a common inherited peripheral neuropathy. The CMT2K axonal form is associated with GDAP1 dominant mutations, which according to the affected domain cause a gradient of severity. Indeed, the p.C240Y mutation, located within GDAP1 glutathione S-transferase (GST) domain and associated to a mitochondrial complex I defect, is related to a faster disease progression, compared to other mutations, such as the p.R120W located outside the GST domain. Here, we analysed the pathophysiology of six CMT2K fibroblast cell lines, carrying either the p.C240Y or p.R120W mutations. We show that complex I deficiency leads to a redox potential alteration and a significant reduction of sirtuin 1 (SIRT1) expression, a major deacetylase sensitive to the cellular redox state, and NRF1 the downstream target of SIRT1. In addition, we disclosed that the p.C240Y mutation is associated with a greater mitochondrial oxidative stress than the p.R120W mutation. Moreover, complex I activity is further restored in CMT2K mutant cell lines exposed to resveratrol. Together, these results suggest that the reduction of oxidative stress may constitute a promising therapeutic strategy for CMT2K.


Assuntos
Doença de Charcot-Marie-Tooth/genética , Doença de Charcot-Marie-Tooth/fisiopatologia , Fibroblastos/metabolismo , Mitocôndrias/fisiologia , Proteínas do Tecido Nervoso/genética , Estresse Oxidativo/fisiologia , Antioxidantes/farmacologia , Linhagem Celular , Complexo I de Transporte de Elétrons/metabolismo , Humanos , Mutação , Resveratrol/farmacologia
15.
J Matern Fetal Neonatal Med ; : 1-4, 2019 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-31510824

RESUMO

Desbuquois dysplasia is a very severe and sometimes lethal form of osteochondrodysplasia characterized by prenatal onset of severe micromelic short stature, joint laxity with multiple joint dislocations, specific radiographic features, and facial dysmorphism. Here, we report a case for which whole exome sequencing allowed early prenatal diagnosis of Desbuquois dysplasia before the detection of characteristic ultrasound signs of the disease.

16.
Clin Genet ; 96(4): 354-358, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31290144

RESUMO

TTI2 (MIM 614126) has been described as responsible for autosomal recessive intellectual disability (ID; MRT39, MIM:615541) in only two inbred families. Here, we give an account of two individuals from two unrelated outbred families harbouring compound heterozygous TTI2 pathogenic variants. Together with severe ID, progressive microcephaly, scoliosis and sleeping disorder are the most striking features in the two individuals concerned. TTI2, together with TTI1 and TELO2, encode proteins that constitute the triple T heterotrimeric complex. This TTT complex interacts with the HSP90 and R2TP to form a super-complex that has a chaperone function stabilising and maturing a number of kinases, such as ataxia-telangiectasia mutated and mechanistic target of rapamycin, which are key regulators of cell proliferation and genome maintenance. Pathogenic variants in TTI2 logically result in a phenotype close to that caused by TELO2 variants.

17.
Genet Med ; 21(12): 2723-2733, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31239556

RESUMO

PURPOSE: Pathogenic variants in the chromatin organizer CTCF were previously reported in seven individuals with a neurodevelopmental disorder (NDD). METHODS: Through international collaboration we collected data from 39 subjects with variants in CTCF. We performed transcriptome analysis on RNA from blood samples and utilized Drosophila melanogaster to investigate the impact of Ctcf dosage alteration on nervous system development and function. RESULTS: The individuals in our cohort carried 2 deletions, 8 likely gene-disruptive, 2 splice-site, and 20 different missense variants, most of them de novo. Two cases were familial. The associated phenotype was of variable severity extending from mild developmental delay or normal IQ to severe intellectual disability. Feeding difficulties and behavioral abnormalities were common, and variable other findings including growth restriction and cardiac defects were observed. RNA-sequencing in five individuals identified 3828 deregulated genes enriched for known NDD genes and biological processes such as transcriptional regulation. Ctcf dosage alteration in Drosophila resulted in impaired gross neurological functioning and learning and memory deficits. CONCLUSION: We significantly broaden the mutational and clinical spectrum ofCTCF-associated NDDs. Our data shed light onto the functional role of CTCF by identifying deregulated genes and show that Ctcf alterations result in nervous system defects in Drosophila.


Assuntos
Fator de Ligação a CCCTC/genética , Fator de Ligação a CCCTC/metabolismo , Transtornos do Neurodesenvolvimento/genética , Animais , Criança , Cromatina/genética , Cromatina/metabolismo , Deficiências do Desenvolvimento/genética , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/genética , Drosophila melanogaster/metabolismo , Feminino , Perfilação da Expressão Gênica/métodos , Regulação da Expressão Gênica/genética , Humanos , Deficiência Intelectual/genética , Masculino , Mutação/genética , Mutação de Sentido Incorreto/genética , Transtornos do Neurodesenvolvimento/metabolismo , Fatores de Transcrição/genética , Sequenciamento Completo do Exoma/métodos , Adulto Jovem
18.
J Proteome Res ; 18(7): 2779-2790, 2019 07 05.
Artigo em Inglês | MEDLINE | ID: mdl-31199663

RESUMO

OPA1 is a dynamin GTPase implicated in mitochondrial membrane fusion. Despite its involvement in lipid remodeling, the function of OPA1 has never been analyzed by whole-cell lipidomics. We used a nontargeted, reversed-phase lipidomics approach, validated for cell cultures, to investigate OPA1-inactivated mouse embryonic fibroblasts ( Opa1 -/- MEFs). This led to the identification of a wide range of 14 different lipid subclasses comprising 212 accurately detected lipids. Multivariate and univariate statistical analyses were then carried out to assess the differences between the Opa1 -/- and Opa1 +/+ genotypes. Of the 212 lipids identified, 69 were found to discriminate between Opa1 -/- MEFs and Opa1 +/+ MEFs. Among these lipids, 34 were triglycerides, all of which were at higher levels in Opa1 -/- MEFs with fold changes ranging from 3.60 to 17.93. Cell imaging with labeled fatty acids revealed a sharp alteration of the fatty acid flux with a reduced mitochondrial uptake. The other 35 discriminating lipids included phosphatidylcholines, lysophosphatidylcholines, phosphatidylethanolamine, and sphingomyelins, mainly involved in membrane remodeling, and ceramides, gangliosides, and phosphatidylinositols, mainly involved in apoptotic cell signaling. Our results show that the inactivation of OPA1 severely affects the mitochondrial uptake of fatty acids and lipids through membrane remodeling and apoptotic cell signaling.

19.
Invest Ophthalmol Vis Sci ; 60(7): 2509-2514, 2019 06 03.
Artigo em Inglês | MEDLINE | ID: mdl-31185090

RESUMO

Purpose: To investigate the plasma concentration of nicotinamide in primary open-angle glaucoma (POAG). Methods: Plasma of 34 POAG individuals was compared to that of 30 age- and sex-matched controls using a semiquantitative method based on liquid chromatography coupled to high-resolution mass spectrometry. Subsequently, an independent quantitative method, based on liquid chromatography coupled to mass spectrometry, was used to assess nicotinamide concentration in the plasma from the same initial cohort and from a replicative cohort of 20 POAG individuals and 15 controls. Results: Using the semiquantitative method, the plasma nicotinamide concentration was significantly lower in the initial cohort of POAG individuals compared to controls and further confirmed in the same cohort, using the targeted quantitative method, with mean concentrations of 0.14 µM (median: 0.12 µM; range, 0.06-0.28 µM) in the POAG group (-30%; P = 0.022) and 0.19 µM (median: 0.18 µM; range, 0.08-0.47 µM) in the control group. The quantitative dosage also disclosed a significantly lower plasma nicotinamide concentration (-33%; P = 0.011) in the replicative cohort with mean concentrations of 0.14 µM (median: 0.14 µM; range, 0.09-0.25 µM) in the POAG group, and 0.19 µM (median: 0.21 µM; range, 0.09-0.26 µM) in the control group. Conclusions: Glaucoma is associated with lower plasmatic nicotinamide levels, compared to controls, suggesting that nicotinamide supplementation might become a future therapeutic strategy. Further studies are needed, in larger cohorts, to confirm these preliminary findings.


Assuntos
Glaucoma de Ângulo Aberto/sangue , Niacinamida/deficiência , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos de Casos e Controles , Cromatografia Líquida , Estudos de Coortes , Feminino , Glaucoma de Ângulo Aberto/diagnóstico , Humanos , Pressão Intraocular , Masculino , Pessoa de Meia-Idade , Espectrometria de Massas por Ionização por Electrospray
20.
Biochim Biophys Acta Mol Basis Dis ; 1865(9): 2475-2489, 2019 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-31121247

RESUMO

Due to its pivotal role in NADH oxidation and ATP synthesis, mitochondrial complex I (CI) emerged as a crucial regulator of cellular metabolism. A functional CI relies on the sequential assembly of nuclear- and mtDNA-encoded subunits; however, whether CI assembly status is involved in the metabolic adaptations in CI deficiency still remains largely unknown. Here, we investigated the relationship between CI functions, its structure and the cellular metabolism in 29 patient fibroblasts representative of most CI mitochondrial diseases. Our results show that, contrary to the generally accepted view, a complex I deficiency does not necessarily lead to a glycolytic switch, i.e. the so-called Warburg effect, but that this particular metabolic adaptation is a feature of CI assembly defect. By contrast, a CI functional defect without disassembly induces a higher catabolism to sustain the oxidative metabolism. Mechanistically, we demonstrate that reactive oxygen species overproduction by CI assembly intermediates and subsequent AMPK-dependent Pyruvate Dehydrogenase inactivation are key players of this metabolic reprogramming. Thus, this study provides a two-way-model of metabolic responses to CI deficiencies that are central not only in defining therapeutic strategies for mitochondrial diseases, but also in all pathophysiological conditions involving a CI deficiency.


Assuntos
Complexo I de Transporte de Elétrons/metabolismo , Mitocôndrias/metabolismo , Ciclo do Ácido Cítrico , Fibroblastos/citologia , Fibroblastos/metabolismo , Glicólise , Humanos , Engenharia Metabólica , Doenças Mitocondriais/metabolismo , Doenças Mitocondriais/patologia , NADH Desidrogenase/antagonistas & inibidores , NADH Desidrogenase/genética , NADH Desidrogenase/metabolismo , Análise de Componente Principal , Interferência de RNA , RNA Interferente Pequeno/metabolismo , Espécies Reativas de Oxigênio/metabolismo
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