Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 383
Filtrar
1.
Zhongguo Dang Dai Er Ke Za Zhi ; 26(9): 940-945, 2024.
Artigo em Chinês | MEDLINE | ID: mdl-39267509

RESUMO

OBJECTIVES: To explore early diagnostic biological markers for Leigh syndrome caused by the m.8993T>G mutation. METHODS: A retrospective analysis was performed on the clinical data of four children diagnosed with m.8993T>G mutation-related mitochondrial disease at the Children's Hospital of Chongqing Medical University from January 2014 to January 2024. Additionally, a literature review was conducted. RESULTS: All four children had plasma amino acid and acylcarnitine analyses that revealed decreased citrulline levels, and one child was initially identified through neonatal genetic metabolic disease screening. According to the literature review, there were 26 children with mitochondrial disease and hypocitrullinemia caused by the m.8993T>G mutation (including the four children in this study). Among these, 12 children exhibited clinical phenotypes of Leigh syndrome or Leigh-like syndrome, while 18 children were identified with hypocitrullinemia and/or elevated levels of 3-hydroxyisovalerylcarnitine (C5-OH) during neonatal genetic metabolic disease screening. CONCLUSIONS: Hypocitrullinemia may serve as a potential biomarker for the early diagnosis of m.8993T>G mutation-associated Leigh syndrome, detectable as early as during neonatal genetic metabolic disease screening.


Assuntos
Citrulina , Doença de Leigh , Mutação , Humanos , Doença de Leigh/genética , Masculino , Feminino , Lactente , Citrulina/sangue , Pré-Escolar , Recém-Nascido , Carnitina/análogos & derivados , Carnitina/sangue , Estudos Retrospectivos
2.
BMC Res Notes ; 17(1): 228, 2024 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-39152498

RESUMO

OBJECTIVES: Cox10 is an enzyme required for the activity of cytochrome c oxidase. Humans who lack at least one functional copy of Cox10 have a form of Leigh Syndrome, a genetic disease that is usually fatal in infancy. As more human genomes are sequenced, new alleles are being discovered; whether or not these alleles encode functional proteins remains unclear. Thus, we set out to measure the phenotypes of many human Cox10 variants by expressing them in yeast cells. RESULTS: We successfully expressed the reference sequence and 25 variants of human Cox10 in yeast. We quantitated the ability of these variants to support growth on nonfermentable media and directly measured cytochrome c oxidase activity. 11 of these Cox10 variants supported approximately half or more the cytochrome c oxidase activity compared to the reference sequence. All of the strains containing those 11 variants also grew robustly using a nonfermentable carbon source. Cells expressing the other variants showed low cytochrome c oxidase activity and failed to grow on nonfermentable media.


Assuntos
Complexo IV da Cadeia de Transporte de Elétrons , Doença de Leigh , Fenótipo , Doença de Leigh/genética , Complexo IV da Cadeia de Transporte de Elétrons/genética , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Humanos , Saccharomyces cerevisiae/genética , Variação Genética , Proteínas de Membrana , Alquil e Aril Transferases
3.
Methods Mol Biol ; 2835: 121-133, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39105911

RESUMO

Leigh syndrome (LS), a complex multisystemic disorder, poses significant challenges in genetic medicine due to its intricate pathogenesis and wide-ranging clinical manifestations. Notably, these arise from mutations in either nuclear genetic DNA or mitochondrial DNA, affecting ATP production and resulting in diverse clinical outcomes. The unpredictable trajectory of this disease, ranging from severe developmental delays to early mortality, underscores the need for improved therapeutic solutions. This research pivots toward the novel use of induced pluripotent stem cells (iPSCs) as a promising platform for understanding disease mechanisms and spearheading patient-specific drug discoveries. Given the past successes of iPSCs in delineating organ-specific disorders and the recent endorsement of human iPSC-derived cardiomyocytes (CMs) by the FDA for drug evaluation, our work seeks to bridge this innovation to Leigh syndrome research. We detail a methodological approach to generate iPSCs from LS patients and differentiate them into iPSCs-CMs. Using multi-electrode array (MEA) analyses, we evaluate the field potential of these cells, spotlighting the potential of hiPSC-CM in drug validation and disease modeling. This pioneering approach offers a glimpse into the future of patient-centric therapeutic interventions for Leigh/Leigh-like syndrome.


Assuntos
Diferenciação Celular , Células-Tronco Pluripotentes Induzidas , Doença de Leigh , Miócitos Cardíacos , Células-Tronco Pluripotentes Induzidas/metabolismo , Células-Tronco Pluripotentes Induzidas/citologia , Humanos , Doença de Leigh/genética , Doença de Leigh/metabolismo , Miócitos Cardíacos/metabolismo , Miócitos Cardíacos/citologia , Células Cultivadas , Técnicas de Cultura de Células/métodos , Avaliação Pré-Clínica de Medicamentos/métodos
4.
Mol Syndromol ; 15(4): 333-338, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-39119452

RESUMO

Introduction: Leigh syndrome is a rare mitochondrial disorder characterized by subacute necrotizing encephalomyelopathy, resulting from defects in mitochondrial respiratory enzymes or pyruvate dehydrogenase complex. Symptoms can manifest in infancy, childhood, or adulthood. We present a case of a 7-month-old girl initially misdiagnosed with septic shock but was later found to have Leigh encephalomyelopathy due to MT-ATP6 deficiency. Case Presentation: A 7-month-old girl was admitted with fever, drowsiness, and wheezing, initially diagnosed with septic shock. She had a history of parental consanguinity and hypotonia. Physical examination revealed unconsciousness, miotic pupils, and respiratory distress. Initial laboratory tests showed significant metabolic acidosis and elevated lactate, creatine kinase, and ammonia levels. The patient was treated for sepsis and shock, but her condition worsened with elevated lactate and liver transaminases, eventually leading to hypertrophic cardiomyopathy and multiorgan failure. Her basic metabolic scans showed extremely low citrulline levels, whole-exome sequencing analysis did not show any pathologic change in nuclear genome, and mitochondrial genome analysis revealed an MT-ATP homoplasmic variant. She passed away on the 22nd day of hospitalization. Discussion/Conclusion: While mitochondrial disorders are broadly acknowledged for their phenotypic diversity, it is essential to note that specific disorders, such as Leigh syndrome, display distinctive presentations with varying degrees of severity. Factors such as the percentage of homoplasmy contribute to the variability in manifestations. Notably, MT-ATP6-associated Leigh syndrome is predominantly characterized by an early onset, typically occurring before the age of 2 years. Low citrulline levels have been observed in approximately 90% of patients with MT-ATP6-related disorders, distinguishing them from other mitochondrial disorders. The exact mechanisms underlying this specific metabolic alteration are not fully understood, but it could be linked to disruptions in the mitochondrial energy production process. The mitochondria are essential for various metabolic pathways, including the urea cycle, where citrulline is involved. The association between low citrulline levels and MT-ATP6-related disorders raises the possibility of using citrulline as a potential biomarker for disease identification. MT-ATP6 defects should be kept in mind in cases with mitochondrial disease and low plasma citrulline levels.

5.
Orphanet J Rare Dis ; 19(1): 305, 2024 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-39169373

RESUMO

BACKGROUND: Leigh syndrome (LS) is a common mitochondrial disease caused by mutations in both mitochondrial and nuclear genes. Isoleucyl-tRNA synthetase 2 (IARS2) encodes mitochondrial isoleucine-tRNA synthetase, and variants in IARS2 have been reported to cause LS. However, the pathogenic mechanism of IARS2 variants is still unclear. METHODS: Two unrelated patients, a 4-year-old boy and a 5-year-old boy diagnosed with LS, were recruited, and detailed clinical data were collected. The DNA of the patients and their parents was isolated from the peripheral blood for the identification of pathogenic variants using next-generation sequencing and Sanger sequencing. The ClustalW program, allele frequency analysis databases (gnomAD and ExAc), and pathogenicity prediction databases (Clinvar, Mutation Taster and PolyPhen2) were used to predict the conservation and pathogenicity of the variants. The gene expression level, oxygen consumption rate (OCR), respiratory chain complex activity, cellular adenosine triphosphate (ATP) production, mitochondrial membrane potential (MMP) and mitochondrial reactive oxygen species (ROS) levels were measured in patient-derived lymphocytes and IARS2-knockdown HEK293T cells to evaluate the pathogenicity of the variants. RESULTS: We reported 2 unrelated Chinese patients manifested with LS who carried biallelic IARS2 variants (c.1_390del and c.2450G > A from a 4-year-old boy, and c.2090G > A and c.2122G > A from a 5-year-old boy), of which c.1_390del and c.2090G > A were novel. Functional studies revealed that the patient-derived lymphocytes carrying c.1_390del and c.2450G > A variants exhibited impaired mitochondrial function due to severe mitochondrial complexes I and III deficiencies, which was also found in IARS2-knockdown HEK293T cells. The compensatory experiments in vitro cell models confirmed the pathogenicity of IARS2 variants since re-expression of wild-type IARS2 rather than mutant IARS2 could rescue complexes I and III deficiency, oxygen consumption, and cellular ATP content in IARS2 knockdown cells. CONCLUSION: Our results not only expand the gene mutation spectrum of LS, but also reveal for the first time the pathogenic mechanism of IARS2 variants due to a combined deficiency of mitochondrial complexes I and III, which is helpful for the clinical diagnosis of IARS2 mutation-related diseases.


Assuntos
Doença de Leigh , Mutação , Fosforilação Oxidativa , Humanos , Doença de Leigh/genética , Doença de Leigh/patologia , Doença de Leigh/metabolismo , Masculino , Pré-Escolar , Mutação/genética , Células HEK293 , Potencial da Membrana Mitocondrial , Aminoacil-tRNA Sintetases/genética , Aminoacil-tRNA Sintetases/metabolismo
6.
Am J Med Genet C Semin Med Genet ; : e32106, 2024 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-39166720
8.
Pediatr Radiol ; 54(10): 1758-1762, 2024 09.
Artigo em Inglês | MEDLINE | ID: mdl-39066889

RESUMO

A 23-month-old boy with poor growth, developmental delay, and hypotonia presented with acute onset of ataxia and fatigue. Magnetic resonance imaging (MRI) of the brain and spinal cord was performed as part of diagnostic work-up. MRI showed bilateral symmetrical lesions in basal ganglia, midbrain, and brainstem consistent with Leigh syndrome. Signal abnormalities were also present within the cervical cord, with enhancement of multiple cranial, spinal, and cauda equina nerve roots. Genetic testing confirmed compound heterozygosity for two pathogenic variants in SURF1 implicated in Leigh syndrome. Whilst nerve root enhancement has been described in other mitochondrial disorders, we believe this is the first published case of both cranial and spinal nerve root enhancement in Leigh syndrome.


Assuntos
Doença de Leigh , Imageamento por Ressonância Magnética , Proteínas de Membrana , Proteínas Mitocondriais , Humanos , Doença de Leigh/diagnóstico por imagem , Doença de Leigh/genética , Masculino , Lactente , Imageamento por Ressonância Magnética/métodos , Proteínas de Membrana/genética , Proteínas Mitocondriais/genética
9.
Biochim Biophys Acta Bioenerg ; 1865(4): 149491, 2024 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-38960077

RESUMO

Energy converting NADH:ubiquinone oxidoreductase, complex I, is the first enzyme of respiratory chains in most eukaryotes and many bacteria. Mutations in genes encoding subunits of human complex I may lead to its dysfunction resulting in a diverse clinical pattern. The effect of mutations on the protein structure is not known. Here, we focus on mutations R88G, E246K, P252R and E377K that are found in subunit NDUFV1 comprising the NADH binding site of complex I. Homologous mutations were introduced into subunit NuoF of Aquifex aeolicus complex I and it was attempted to crystallize variants of the electron input module, NuoEF, with bound substrates in the oxidized and reduced state. The E377K variant did not form crystals most likely due to an improper protein assembly. The architecture of the NADH binding site is hardly affected by the other mutations indicating its unexpected structural robustness. The R88G, E246K and P252R mutations led to small local structural rearrangements that might be related to their pathogenicity. These minor structural changes involve substrate binding, product release and the putative formation of reactive oxygen species. The structural consequences of the mutations as obtained with the bacterial enzyme might thus help to contribute to the understanding of disease causing mutations.


Assuntos
Complexo I de Transporte de Elétrons , NAD , Complexo I de Transporte de Elétrons/metabolismo , Complexo I de Transporte de Elétrons/química , Complexo I de Transporte de Elétrons/genética , Sítios de Ligação , NAD/metabolismo , Aquifex/enzimologia , Aquifex/metabolismo , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Mutação , Modelos Moleculares , Humanos , Cristalografia por Raios X , Conformação Proteica
10.
Res Sq ; 2024 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-38883711

RESUMO

Background: Genetic mitochondrial diseases are a major challenge in modern medicine, impacting around 1:4,000 individuals. Leigh syndrome is the most common pediatric presentation of mitochondrial disease. There are currently no effective clinical treatments for mitochondrial disease. In humans, patients are often treated with antioxidants, vitamins, and strategies targeting energetics. The vitamin-E related compound vatiquinone (EPI-743, α-tocotrienol quinone) has been the subject of at least 19 clinical trials in the US since 2012, but the effects of vatiquinone on an animal model of mitochondrial disease have not yet been reported. Here, assessed the impact of vatiquinone on disease progression and in two animal models of mitochondrial disease. Methods: The efficacy of vatiquinone in vitro was assessed using human fibroblasts treated with the general mitochondrial oxidative stress inducer paraquat, the GPX4 inhibitor RSL3, or the glutathione synthase inhibitor BSO in combination with excess iron. The therapeutic potential of vatiquinone in vivo was assessed using tamoxifen-induced mouse model for GPX4 deficiency and the Ndufs4 knockout mouse model of Leigh syndrome. In both models, animals were treated daily with vatiquinone or vehicle and relevant disease endpoints were assessed. Results: Vatiquinone robustly prevented death in cultured cells induced by RSL3 or BSO/iron, but had no effect on paraquat induced cell death. Vatiquinone had no impact on disease onset, progression, or survival in either the tamoxifen-inducible GPX4 deficient model or the Ndufs4(-/-) mouse model, though the drug may have reduced seizure risk. Conclusions: Vatiquinone provided no benefit to survival in two mouse models of disease, but may prevent seizures in the Ndufs4(-/-) model. Our findings are consistent with recent press statements regarding clinical trial results and have implications for drug trial design and reporting in patients with rare diseases.

11.
Pediatr Neurol ; 157: 29-38, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38848614

RESUMO

BACKGROUND: Six percent of patients with Leigh syndrome (LS) present with infantile epileptic spasms syndrome (IESS). However, treatment strategies for IESS with LS remain unclear. This retrospective study aimed to evaluate the efficacy and safety of treatment strategies in patients with IESS complicated by LS and Leigh-like syndrome (LLS). METHODS: We distributed questionnaires to 750 facilities in Japan, and the clinical data of 21 patients from 15 hospitals were collected. The data comprised treatment strategies, including adrenocorticotropic hormone (ACTH) therapy, ketogenic diet (KD) therapy, and antiseizure medications (ASMs); effectiveness of each treatment; and the adverse events. RESULTS: The median age at LS and LLS diagnosis was 7 months (range: 0 to 50), whereas that at the onset of epileptic spasms was 7 (range: 3 to 20). LS was diagnosed in 17 patients and LLS in four patients. Seven, two, five, and seven patients received ACTH + ASMs, ACTH + KD + ASMs, KD + ASMs, and ASMs only, respectively. Four (44%) of nine patients treated with ACTH and one (14%) of seven patients treated with KD achieved electroclinical remission within one month of treatment. No patients treated with only ASMs achieved electroclinical remission. Seven patients (33%) achieved electroclinical remission by the last follow-up. Adverse events were reported in four patients treated with ACTH, none treated with KD therapy, and eight treated with ASMs. CONCLUSION: ACTH therapy shows the best efficacy and rapid action in patients with IESS complicated by LS and LLS. The effectiveness of KD therapy and ASMs in this study was insufficient.


Assuntos
Hormônio Adrenocorticotrópico , Anticonvulsivantes , Dieta Cetogênica , Doença de Leigh , Espasmos Infantis , Humanos , Doença de Leigh/complicações , Lactente , Espasmos Infantis/tratamento farmacológico , Espasmos Infantis/complicações , Estudos Retrospectivos , Feminino , Masculino , Anticonvulsivantes/uso terapêutico , Japão , Pré-Escolar , Hormônio Adrenocorticotrópico/administração & dosagem , Recém-Nascido
12.
Cureus ; 16(5): e59669, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38836159

RESUMO

Although Leigh syndrome (LS) is a neurodegenerative disorder of infancy, adult-onset LS has also been rarely reported. We report a case of late-onset LS in a 42-year-old female who presented with protracted gastrointestinal manifestations, chronic headaches, ataxia, and loss of consciousness. Brain magnetic resonance imaging (MRI) revealed hyperintensities in the bilateral basal ganglia and brain stem. Serum and cerebrospinal fluid lactate levels were significantly raised. Muscle biopsy showed reduced cytochrome oxidase (COX) activity. She was diagnosed with probable diagnosis of late-onset LS based on her clinical features, radiological findings, biochemical results, and biopsy findings. She responded well to intravenous thiamine, and her symptoms gradually improved.

13.
Int J Mol Sci ; 25(9)2024 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-38732047

RESUMO

Mitochondrial dysfunction plays a major role in physiological aging and in many pathological conditions. Yet, no study has explored the consequence of primary mitochondrial deficiency on the blood-brain barrier (BBB) structure and function. Addressing this question has major implications for pharmacological and genetic strategies aimed at ameliorating the neurological symptoms that are often predominant in patients suffering from these conditions. In this study, we examined the permeability of the BBB in the Ndufs4-/- mouse model of Leigh syndrome (LS). Our results indicated that the structural and functional integrity of the BBB was preserved in this severe model of mitochondrial disease. Our findings suggests that pharmacological or gene therapy strategies targeting the central nervous system in this mouse model and possibly other models of mitochondrial dysfunction require the use of specific tools to bypass the BBB. In addition, they raise the need for testing the integrity of the BBB in complementary in vivo models.


Assuntos
Barreira Hematoencefálica , Modelos Animais de Doenças , Complexo I de Transporte de Elétrons , Doença de Leigh , Animais , Camundongos , Barreira Hematoencefálica/metabolismo , Complexo I de Transporte de Elétrons/metabolismo , Complexo I de Transporte de Elétrons/genética , Complexo I de Transporte de Elétrons/deficiência , Doença de Leigh/genética , Doença de Leigh/metabolismo , Doença de Leigh/patologia , Camundongos Knockout , Mitocôndrias/metabolismo , Mitocôndrias/genética
14.
Int J Mol Sci ; 25(10)2024 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-38791166

RESUMO

Movement disorders such as bradykinesia, tremor, dystonia, chorea, and myoclonus most often arise in several neurodegenerative diseases with basal ganglia and white matter involvement. While the pathophysiology of these disorders remains incompletely understood, dysfunction of the basal ganglia and related brain regions is often implicated. The VPS13D gene, part of the VPS13 family, has emerged as a crucial player in neurological pathology, implicated in diverse phenotypes ranging from movement disorders to Leigh syndrome. We present a clinical case of VPS13D-associated disease with two variants in the VPS13D gene in an adult female. This case contributes to our evolving understanding of VPS13D-related diseases and underscores the importance of genetic screening in diagnosing and managing such conditions.


Assuntos
Ataxias Espinocerebelares , Humanos , Feminino , Ataxias Espinocerebelares/genética , Ataxias Espinocerebelares/diagnóstico , Ataxias Espinocerebelares/congênito , Proteínas de Transporte Vesicular/genética , Adulto , Fenótipo , Mutação , Genes Recessivos , Linhagem , Proteínas
15.
Front Genet ; 15: 1375467, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38706791

RESUMO

Leigh syndrome French Canadian type (LSFC) is a recessive neurodegenerative disease characterized by tissue-specific deficiency in cytochrome c oxidase (COX), the fourth complex in the oxidative phosphorylation system. LSFC is caused by mutations in the leucine rich pentatricopeptide repeat containing gene (LRPPRC). Most LSFC patients in Quebec are homozygous for an A354V substitution that causes a decrease in the expression of the LRPPRC protein. While LRPPRC is ubiquitously expressed and is involved in multiple cellular functions, tissue-specific expression of LRPPRC and COX activity is correlated with clinical features. In this proof-of-principle study, we developed human induced pluripotent stem cell (hiPSC)-based models from fibroblasts taken from a patient with LSFC, homozygous for the LRPPRC*354V allele, and from a control, homozygous for the LRPPRC*A354 allele. Specifically, for both of these fibroblast lines we generated hiPSC, hiPSC-derived cardiomyocytes (hiPSC-CMs) and hepatocyte-like cell (hiPSC-HLCs) lines, as well as the three germ layers. We observed that LRPPRC protein expression is reduced in all cell lines/layers derived from LSFC patient compared to control cells, with a reduction ranging from ∼70% in hiPSC-CMs to undetectable levels in hiPSC-HLC, reflecting tissue heterogeneity observed in patient tissues. We next performed exploratory analyses of these cell lines and observed that COX protein expression was reduced in all cell lines derived from LSFC patient compared to control cells. We also observed that mutant LRPPRC was associated with altered expression of key markers of endoplasmic reticulum stress response in hiPSC-HLCs but not in other cell types that were tested. While this demonstrates feasibility of the approach to experimentally study genotype-based differences that have tissue-specific impacts, this study will need to be extended to a larger number of patients and controls to not only validate the current observations but also to delve more deeply in the pathogenic mechanisms of LSFC.

16.
Genes (Basel) ; 15(4)2024 04 17.
Artigo em Inglês | MEDLINE | ID: mdl-38674434

RESUMO

Oxidative phosphorylation involves a complex multi-enzymatic mitochondrial machinery critical for proper functioning of the cell, and defects herein cause a wide range of diseases called "primary mitochondrial disorders" (PMDs). Mutations in about 400 nuclear and 37 mitochondrial genes have been documented to cause PMDs, which have an estimated birth prevalence of 1:5000. Here, we describe a 4-year-old female presenting from early childhood with psychomotor delay and white matter signal changes affecting several brain regions, including the brainstem, in addition to lactic and phytanic acidosis, compatible with Leigh syndrome, a genetically heterogeneous subgroup of PMDs. Whole genome sequencing of the family trio identified a homozygous 12.9 Kb deletion, entirely overlapping the NDUFA4 gene. Sanger sequencing of the breakpoints revealed that the genomic rearrangement was likely triggered by Alu elements flanking the gene. NDUFA4 encodes for a subunit of the respiratory chain Complex IV, whose activity was significantly reduced in the patient's fibroblasts. In one family, dysfunction of NDUFA4 was previously documented as causing mitochondrial Complex IV deficiency nuclear type 21 (MC4DN21, OMIM 619065), a relatively mild form of Leigh syndrome. Our finding confirms the loss of NDUFA4 function as an ultra-rare cause of Complex IV defect, clinically presenting as Leigh syndrome.


Assuntos
Complexo I de Transporte de Elétrons , Doença de Leigh , Humanos , Doença de Leigh/genética , Doença de Leigh/patologia , Feminino , Pré-Escolar , Complexo IV da Cadeia de Transporte de Elétrons/genética , Doenças Mitocondriais/genética , Doenças Mitocondriais/patologia , Linhagem , Deleção de Sequência
17.
Cell Rep ; 43(4): 114067, 2024 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-38583150

RESUMO

Mitochondrial dysfunction critically contributes to many major human diseases. The impact of specific gut microbial metabolites on mitochondrial functions of animals and the underlying mechanisms remain to be uncovered. Here, we report a profound role of bacterial peptidoglycan muropeptides in promoting mitochondrial functions in multiple mammalian models. Muropeptide addition to human intestinal epithelial cells (IECs) leads to increased oxidative respiration and ATP production and decreased oxidative stress. Strikingly, muropeptide treatment recovers mitochondrial structure and functions and inhibits several pathological phenotypes of fibroblast cells derived from patients with mitochondrial disease. In mice, muropeptides accumulate in mitochondria of IECs and promote small intestinal homeostasis and nutrient absorption by modulating energy metabolism. Muropeptides directly bind to ATP synthase, stabilize the complex, and promote its enzymatic activity in vitro, supporting the hypothesis that muropeptides promote mitochondria homeostasis at least in part by acting as ATP synthase agonists. This study reveals a potential treatment for human mitochondrial diseases.


Assuntos
Mitocôndrias , Fosforilação Oxidativa , Animais , Humanos , Mitocôndrias/metabolismo , Mitocôndrias/efeitos dos fármacos , Fosforilação Oxidativa/efeitos dos fármacos , Camundongos , Estresse Oxidativo/efeitos dos fármacos , Peptidoglicano/metabolismo , Camundongos Endogâmicos C57BL , Trifosfato de Adenosina/metabolismo
18.
Pediatr Neurol ; 155: 91-103, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38626668

RESUMO

BACKGROUND: Pathogenic variants in the NDUFV1 gene disrupt mitochondrial complex I, leading to neuroregression with leukoencephalopathy and basal ganglia involvement on neuroimaging. This study aims to provide a concise review on NDUFV1-related disorders while adding the largest cohort from a single center to the existing literature. METHODS: We retrospectively collected genetically proven cases of NDUFV1 pathogenic variants from our center over the last decade and explored reported instances in existing literature. Magnetic resonance imaging (MRI) patterns observed in these patients were split into three types-Leigh (putamen, basal ganglia, thalamus, and brainstem involvement), mitochondrial leukodystrophy (ML) (cerebral white matter involvement with cystic cavitations), and mixed (both). RESULTS: Analysis included 44 children (seven from our center and 37 from literature). The most prevalent comorbidities were hypertonia, ocular abnormalities, feeding issues, and hypotonia at onset. Children with the Leigh-type MRI pattern exhibited significantly higher rates of breathing difficulties, whereas those with a mixed phenotype had a higher prevalence of dystonia. The c.1156C>T variant in exon 8 of the NDUFV1 gene was the most common variant among individuals of Asian ethnicity and is predominantly associated with irritability and dystonia. Seizures and Leigh pattern of MRI of the brain was found to be less commonly associated with this variant. Higher rate of mortality was observed in children with Leigh-type pattern on brain MRI and those who did not receive mitochondrial cocktail. CONCLUSIONS: MRI phenotyping might help predict outcome. Appropriate and timely treatment with mitochondrial cocktail may reduce the probability of death and may positively impact the long-term outcomes, regardless of the genetic variant or age of onset.


Assuntos
Complexo I de Transporte de Elétrons , Doenças Mitocondriais , NADH Desidrogenase , Humanos , Estudos Retrospectivos , Masculino , Complexo I de Transporte de Elétrons/genética , Feminino , Pré-Escolar , Lactente , Criança , NADH Desidrogenase/genética , Doenças Mitocondriais/genética , Doenças Mitocondriais/diagnóstico por imagem , Imageamento por Ressonância Magnética , Doença de Leigh/genética , Doença de Leigh/diagnóstico por imagem , Adolescente
19.
Mov Disord ; 39(7): 1225-1231, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38685873

RESUMO

BACKGROUND: The MRPS36 gene encodes a recently identified component of the 2-oxoglutarate dehydrogenase complex (OGDHC), a key enzyme of the Krebs cycle catalyzing the oxidative decarboxylation of 2-oxoglutarate to succinyl-CoA. Defective OGDHC activity causes a clinically variable metabolic disorder characterized by global developmental delay, severe neurological impairment, liver failure, and early-onset lactic acidosis. METHODS: We investigated the molecular cause underlying Leigh syndrome with bilateral striatal necrosis in two siblings through exome sequencing. Functional studies included measurement of the OGDHC enzymatic activity and MRPS36 mRNA levels in fibroblasts, assessment of protein stability in transfected cells, and structural analysis. A literature review was performed to define the etiological and phenotypic spectrum of OGDHC deficiency. RESULTS: In the two affected brothers, exome sequencing identified a homozygous nonsense variant (c.283G>T, p.Glu95*) of MRPS36. The variant did not affect transcript processing and stability, nor protein levels, but resulted in a shorter protein lacking nine residues that contribute to the structural and functional organization of the OGDHC complex. OGDHC enzymatic activity was significantly reduced. The review of previously reported cases of OGDHC deficiency supports the association of this enzymatic defect with Leigh phenotypic spectrum and early-onset movement disorder. Slightly elevated plasma levels of glutamate and glutamine were observed in our and literature patients with OGDHC defect. CONCLUSIONS: Our findings point to MRPS36 as a new disease gene implicated in Leigh syndrome. The slight elevation of plasma levels of glutamate and glutamine observed in patients with OGDHC deficiency represents a candidate metabolic signature of this neurometabolic disorder. © 2024 International Parkinson and Movement Disorder Society.


Assuntos
Complexo Cetoglutarato Desidrogenase , Doença de Leigh , Doença de Leigh/genética , Humanos , Masculino , Complexo Cetoglutarato Desidrogenase/genética , Complexo Cetoglutarato Desidrogenase/deficiência , Proteínas Mitocondriais/genética , Pré-Escolar , Lactente
20.
Cureus ; 16(3): e55308, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38559521

RESUMO

MEGDEL syndrome, a rare autosomal recessive disorder characterized by 3-methylglutaconic aciduria, deafness, encephalopathy, and Leigh-like syndrome, results from mutations in the SERAC1 gene. This case report explores the clinical presentation, diagnostic challenges, and genetic findings of an 11-year-old boy with MEGDEL syndrome at a tertiary care center in Saudi Arabia. The patient, born to consanguineous parents, presented with developmental delay, cerebral palsy, intellectual disability, and seizures. Diagnostic evaluation at 15 months revealed 3-methylglutaconic aciduria, and subsequent genetic testing through whole exome sequencing confirmed a rare homozygous deletion variant in the SERAC1 gene. The patient exhibited brain atrophy, tracheal stenosis, laryngomalacia, and skeletal abnormalities. The complexity of MEGDEL syndrome manifestations and the challenge of distinguishing it from other metabolic disorders are discussed, emphasizing the significance of genetic testing in confirming the diagnosis. This case underscores the occurrence of MEGDEL syndrome in a child with cerebral palsy, highlighting the importance of a multidisciplinary approach for diagnosis and the need for genetic counseling in consanguineous families. Although the management remains primarily supportive, the report calls for more comprehensive epidemiological studies to determine the prevalence and incidence of MEGDEL syndrome. The findings contribute to the growing understanding of this rare disorder, thus emphasizing the necessity for ongoing research to enhance diagnostic accuracy and management strategies.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA