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1.
Stem Cell Res ; 76: 103379, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38458030

RESUMO

Leigh syndrome is a rare autosomal recessive disorder showcasing a diverse range of neurological symptoms. Classical Leigh syndrome is associated with mitochondrial complex I deficiency, primarily resulting from biallelic mutations in the NDUFAF5 gene, encoding the NADH:ubiquinone oxidoreductase complex assembly factor 5. Using the Sendai virus delivery system, we generated an induced pluripotent stem cell line from peripheral blood mononuclear cells of a 47-years-old female patient who carried a homozygous NDUFAF5 c.836 T > G (p.Met279Arg) mutation. This cellular model serves as a tool for investigating the underlying pathogenic mechanisms and for the development of potential treatments for Leigh syndrome.


Assuntos
Células-Tronco Pluripotentes Induzidas , Doença de Leigh , Doenças Mitocondriais , Humanos , Feminino , Pessoa de Meia-Idade , Doença de Leigh/genética , Mutação de Sentido Incorreto , Células-Tronco Pluripotentes Induzidas/patologia , Leucócitos Mononucleares/patologia , Doenças Mitocondriais/genética , Doenças Mitocondriais/patologia , Mutação , Metiltransferases/genética , Proteínas Mitocondriais/genética
2.
Orphanet J Rare Dis ; 19(1): 92, 2024 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-38419071

RESUMO

BACKGROUND: Congenital disorders of the mitochondrial respiratory chain are a heterogeneous group of inborn errors of metabolism. Among them, NADH:ubiquinone oxidoreductase (complex I, CI) deficiency is the most common. Biallelic pathogenic variants in NDUFAF2, encoding the nuclear assembly CI factor NDUFAF2, were initially reported to cause progressive encephalopathy beginning in infancy. Since the initial report in 2005, less than a dozen patients with NDUFAF2-related disease have been reported. METHODS: Clinical, biochemical, and neuroradiological features of four new patients residing in Northern Israel were collected during 2016-2022 at Emek Medical Center. Enzymatic activities of the five respiratory-chain complexes were determined in isolated fibroblast mitochondria by spectrophotometric methods. Western blot analyses were conducted with anti-human NDUFAF2 antibody; antibody against the mitochondrial marker VDAC1 was used as a loading control. Genetic studies were performed by chromosome microarray analysis using Affymetrix CytoScan 750 K arrays. RESULTS: All four patients presented with infantile-onset growth retardation, ophthalmological impairments with nystagmus, strabismus (starting between 5 and 9 months), and further progressed to life-threatening episodes of apnea usually triggered by trivial febrile illnesses (between 10 and 18 months) with gradual loss of acquired developmental milestones (3 of 4 patients). Serial magnetic-resonance imaging studies in two of the four patients showed a progressive pattern of abnormal T2-weighted hyperintense signals involving primarily the brainstem, the upper cervical cord, and later, the basal ganglia and thalami. Magnetic-resonance spectroscopy in one patient showed an increased lactate peak. Disease progression was marked by ventilatory dependency and early lethality. 3 of the 4 patients tested, harbored a homozygous 142-kb partial interstitial deletion that omits exons 2-4 of NDUFAF2. Mitochondrial CI activity was significantly decreased in the only patient tested. Western blot analysis disclosed the absence of NDUFAF2 protein compared to normal controls. In addition, we reviewed all 10 previously reported NDUFAF2-deficient cases to better characterize the disease. CONCLUSIONS: Biallelic loss-of-function mutations in NDUFAF2 result in a distinctive phenotype in the spectrum of Leigh syndrome with clinical and neuroradiological features that are primarily attributed to progressive brainstem damage.


Assuntos
Doença de Leigh , Doenças Neurodegenerativas , Humanos , Proteínas Mitocondriais/genética , Proteínas Mitocondriais/metabolismo , Doença de Leigh/genética , Doença de Leigh/metabolismo , Complexo I de Transporte de Elétrons/metabolismo , Tronco Encefálico/patologia , Mutação/genética , Chaperonas Moleculares/genética , Chaperonas Moleculares/metabolismo
3.
Sci Rep ; 14(1): 2975, 2024 02 05.
Artigo em Inglês | MEDLINE | ID: mdl-38316835

RESUMO

Two Jack-Russell Terrier × Chihuahua mixed-breed littermates with Leigh syndrome were investigated. The dogs presented with progressive ataxia, dystonia, and increased lactate levels. Brain MRI showed characteristic bilateral symmetrical T2 hyperintense lesions, histologically representing encephalomalacia. Muscle histopathology revealed accumulation of mitochondria. Whole genome sequencing identified a missense variant in a gene associated with human Leigh syndrome, NDUFS7:c.535G > A or p.(Val179Met). The genotypes at the variant co-segregated with the phenotype in the investigated litter as expected for a monogenic autosomal recessive mode of inheritance. We investigated the functional consequences of the missense variant in a Drosophila melanogaster model by expressing recombinant wildtype or mutant canine NDUFS7 in a ubiquitous knockdown model of the fly ortholog ND-20. Neither of the investigated overexpression lines completely rescued the lethality upon knockdown of the endogenous ND-20. However, a partial rescue was found upon overexpression of wildtype NDUFS7, where pupal lethality was moved to later developmental stages, which was not seen upon canine mutant overexpression, thus providing additional evidence for the pathogenicity of the identified variant. Our results show the potential of the fruit fly as a model for canine disease allele validation and establish NDUFS7:p.(Val179Met) as causative variant for the investigated canine Leigh syndrome.


Assuntos
Distúrbios Distônicos , Doença de Leigh , Animais , Cães , Drosophila melanogaster/genética , Distúrbios Distônicos/genética , Distúrbios Distônicos/veterinária , Doença de Leigh/genética , Doença de Leigh/veterinária , Mutação de Sentido Incorreto
4.
Radiology ; 310(1): e222509, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38289219

RESUMO

HISTORY: A 9-month-old preterm male infant born at 33 weeks gestation presented with a 2-month history of developmental decline. The parents reported that over the past several months, they noted regression of milestones, where the infant stopped smiling, crying, expressing himself, or making eye contact. The parents also reported that the infant had multiple seizures during which he would wake up stiff and stare into space for 10-20 seconds while his lips would become blue. The parents were referred to a neurologist, where physical examination was notable for hypotonia. Electroencephalography (EEG) revealed frequent bilateral parietal epileptiform discharges. The patient was subsequently started on lacosamide. The patient's medical history was notable for abnormally low citrulline levels at birth, with negative results of urea cycle disorder testing at the time, along with left inguinal hernia repair performed 3 months ago. More recent laboratory analysis had shown persistently elevated serum lactate and alanine levels. There was no history of travel, recent infection, or vaccine administration. MRI of the brain with spectroscopy was performed for further evaluation.


Assuntos
Doença de Leigh , Recém-Nascido , Lactente , Humanos , Masculino , Doença de Leigh/diagnóstico por imagem , Encéfalo , Eletroencefalografia , Recém-Nascido Prematuro , Lacosamida
5.
EMBO J ; 43(2): 225-249, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38177503

RESUMO

Respiratory complex I (NADH:ubiquinone oxidoreductase) is essential for cellular energy production and NAD+ homeostasis. Complex I mutations cause neuromuscular, mitochondrial diseases, such as Leigh Syndrome, but their molecular-level consequences remain poorly understood. Here, we use a popular complex I-linked mitochondrial disease model, the ndufs4-/- mouse, to define the structural, biochemical, and functional consequences of the absence of subunit NDUFS4. Cryo-EM analyses of the complex I from ndufs4-/- mouse hearts revealed a loose association of the NADH-dehydrogenase module, and discrete classes containing either assembly factor NDUFAF2 or subunit NDUFS6. Subunit NDUFA12, which replaces its paralogue NDUFAF2 in mature complex I, is absent from all classes, compounding the deletion of NDUFS4 and preventing maturation of an NDUFS4-free enzyme. We propose that NDUFAF2 recruits the NADH-dehydrogenase module during assembly of the complex. Taken together, the findings provide new molecular-level understanding of the ndufs4-/- mouse model and complex I-linked mitochondrial disease.


Assuntos
Doença de Leigh , Doenças Mitocondriais , Animais , Camundongos , Complexo I de Transporte de Elétrons/genética , Complexo I de Transporte de Elétrons/metabolismo , Doença de Leigh/genética , Mitocôndrias/metabolismo , Doenças Mitocondriais/genética , NAD/metabolismo , NADH Desidrogenase/genética , NADH Desidrogenase/metabolismo
7.
Genet Med ; 26(2): 101013, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37924258

RESUMO

PURPOSE: RNF213, encoding a giant E3 ubiquitin ligase, has been recognized for its role as a key susceptibility gene for moyamoya disease. Case reports have also implicated specific variants in RNF213 with an early-onset form of moyamoya disease with full penetrance. We aimed to expand the phenotypic spectrum of monogenic RNF213-related disease and to evaluate genotype-phenotype correlations. METHODS: Patients were identified through reanalysis of exome sequencing data of an unselected cohort of unsolved pediatric cases and through GeneMatcher or ClinVar. Functional characterization was done by proteomics analysis and oxidative phosphorylation enzyme activities using patient-derived fibroblasts. RESULTS: We identified 14 individuals from 13 unrelated families with (de novo) missense variants in RNF213 clustering within or around the Really Interesting New Gene (RING) domain. Individuals presented either with early-onset stroke (n = 11) or with Leigh syndrome (n = 3). No genotype-phenotype correlation could be established. Proteomics using patient-derived fibroblasts revealed no significant differences between clinical subgroups. 3D modeling revealed a clustering of missense variants in the tertiary structure of RNF213 potentially affecting zinc-binding suggesting a gain-of-function or dominant negative effect. CONCLUSION: De novo missense variants in RNF213 clustering in the E3 RING or other regions affecting zinc-binding lead to an early-onset syndrome characterized by stroke or Leigh syndrome.


Assuntos
Doença de Leigh , Doença de Moyamoya , Acidente Vascular Cerebral , Humanos , Criança , Doença de Moyamoya/genética , Doença de Leigh/complicações , Fatores de Transcrição/genética , Ubiquitina-Proteína Ligases/genética , Zinco , Predisposição Genética para Doença , Adenosina Trifosfatases/genética
8.
Pract Neurol ; 24(1): 45-50, 2024 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-37567761

RESUMO

A previously healthy 27-year-old man was admitted to the acute neurology ward with events involving his face, throat and upper limb, which video telemetry later confirmed were refractory focal seizures. He also had progressive pyramidal features, dysarthria and ataxia. MR scans of the brain identified progressive bilateral basal ganglia abnormalities, consistent with Leigh syndrome. However, extensive laboratory and genetic panels did not give a unifying diagnosis. A skeletal muscle biopsy showed no histopathological abnormalities on routine stains. Sequencing of the entire mitochondrial genome in skeletal muscle identified a well-characterised pathogenic variant (m.10191T>C in MT-ND3; NC_012920.1) at 85% heteroplasmy in skeletal muscle. We discuss the clinical and molecular diagnosis of an adult presenting with Leigh syndrome, which is more commonly a paediatric presentation of mitochondrial disease, and how early recognition of a mitochondrial cause is important to support patient care.


Assuntos
Doença de Leigh , Masculino , Adulto , Humanos , Criança , Doença de Leigh/genética , Mutação , Encéfalo/patologia , Músculo Esquelético/patologia , Ataxia
9.
Pharmacol Biochem Behav ; 234: 173689, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38070656

RESUMO

The Ndufs4 knockout (KO) mouse is a validated and robust preclinical model of mitochondrial diseases (specifically Leigh syndrome), that displays a narrow window of relative phenotypical normality, despite its inherent mitochondrial complex I dysfunction and severe phenotype. Preclinical observations related to psychiatric comorbidities that arise in patients with mitochondrial diseases and indeed in Leigh syndrome are, however, yet to be investigated in this model. Strengthening this narrative is the fact that major depression and bipolar disorder are known to present with deficits in mitochondrial function. We therefore screened the behavioural profile of male and female Ndufs4 KO mice (relative to heterozygous; HET and wildtype; WT mice) between postnatal days 28 and 35 for locomotor, depressive- and anxiety-like alterations and linked it with selected brain biomarkers, viz. serotonin, kynurenine, and redox status in brain areas relevant to psychiatric pathologies (i.e., prefrontal cortex, hippocampus, and striatum). The Ndufs4 KO mice initially displayed depressive-like behaviour in the tail suspension test on PND31 but not on PND35 in the forced swim test. In the mirror box test, increased risk resilience was observed. Serotonin levels of KO mice, compared to HET controls, were increased on PND36, together with increased tryptophan to serotonin and kynurenine turnover. Kynurenine to kynurenic acid turnover was however decreased, while reduced versus oxidized glutathione ratio (GSH/GSSG) was increased. When considering the comorbid psychiatric traits of patients with mitochondrial disorders, this work elaborates on the neuropsychiatric profile of the Ndufs KO mouse. Secondly, despite locomotor differences, Ndufs4 KO mice present with a behavioural profile not unlike rodent models of bipolar disorder, namely variable mood states and risk-taking behaviour. The model may elucidate the bio-energetic mechanisms underlying mood disorders, especially in the presence of mitochondrial disease. Studies are however required to further validate the model's translational relevance.


Assuntos
Doença de Leigh , Doenças Mitocondriais , Humanos , Masculino , Feminino , Animais , Camundongos , Doença de Leigh/genética , Doença de Leigh/patologia , Cinurenina , Serotonina , Camundongos Knockout , Transtornos do Humor/genética , Doenças Mitocondriais/genética , Complexo I de Transporte de Elétrons/genética , Complexo I de Transporte de Elétrons/metabolismo
10.
Orphanet J Rare Dis ; 18(1): 355, 2023 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-37974220

RESUMO

BACKGROUND: Leigh syndrome, an inherited neurometabolic disorder, is estimated to be the most common pediatric manifestation of mitochondrial disease. No treatments are currently available for Leigh syndrome due to many hurdles in drug discovery efforts. Leigh syndrome causal variants span over 110 different genes and likely lead to both unique and shared biochemical alterations, often resulting in overlapping phenotypic features. The mechanisms by which pathogenic variants in mitochondrial genes alter cellular phenotype to promote disease remain poorly understood. The rarity of cases of specific causal variants creates barriers to drug discovery and adequately sized clinical trials. BODY: To address the current challenges in drug discovery and facilitate communication between researchers, healthcare providers, patients, and families, the Boston University integrative Cardiovascular Metabolism and Pathophysiology (iCAMP) Lab and Cure Mito Foundation hosted a Leigh Syndrome Symposium. This symposium brought together expert scientists and providers to highlight the current successes in drug discovery and novel models of mitochondrial disease, and to connect patients to providers and scientists to foster community and communication. CONCLUSION: In this symposium review, we describe the research presented, the hurdles ahead, and strategies to better connect the Leigh syndrome community members to advance treatments for Leigh syndrome.


Assuntos
Doença de Leigh , Doenças Mitocondriais , Médicos , Humanos , Criança , Doença de Leigh/tratamento farmacológico , Doença de Leigh/genética , Doença de Leigh/metabolismo , Doenças Mitocondriais/genética , Pessoal de Saúde
13.
Neurobiol Dis ; 187: 106288, 2023 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-37704057

RESUMO

Mutations in the NADH dehydrogenase (ubiquinone reductase) iron­sulfur protein 4 (NDUFS4) gene, which encodes for a key structural subunit of the OXFOS complex I (CI), lead to the most common form of mitochondrial disease in children known as Leigh syndrome (LS). As in other mitochondrial diseases, epileptic seizures constitute one of the most significant clinical features of LS. These seizures are often very difficult to treat and are a sign of poor disease prognosis. Mice with whole-body Ndufs4 KO are a well-validated model of LS; they exhibit epilepsy and several other clinical features of LS. We have previously shown that mice with Ndufs4 KO in only GABAergic interneurons (Gad2-Ndufs4-KO) reproduce the severe epilepsy phenotype observed in the global KO mice. This observation indicated that these mice represent an excellent model of LS epilepsy isolated from other clinical manifestations of the disease. To further characterize this epilepsy phenotype, we investigated seizure susceptibility to selected exogenous seizure triggers in Gad2-Ndufs4-KO mice. Then, using electrophysiology, imaging, and immunohistochemistry, we studied the cellular, physiological, and neuroanatomical consequences of Ndufs4 KO in GABAergic interneurons. Homozygous KO of Ndufs4 in GABAergic interneurons leads to a prominent susceptibility to exogenous seizure triggers, impaired interneuron excitability and interneuron loss. Finally, we found that the hippocampus and cortex participate in the generation of seizure activity in Gad2-Ndufs4-KO mice. These findings further define the LS epilepsy phenotype and provide important insights into the cellular mechanisms underlying epilepsy in LS and other mitochondrial diseases.


Assuntos
Epilepsia , Doença de Leigh , Doenças Mitocondriais , Humanos , Criança , Camundongos , Animais , Doença de Leigh/genética , Convulsões/genética , Complexo I de Transporte de Elétrons/genética , Epilepsia/genética , Interneurônios/metabolismo , Camundongos Knockout
14.
Am J Med Genet A ; 191(12): 2890-2897, 2023 12.
Artigo em Inglês | MEDLINE | ID: mdl-37654102

RESUMO

Mitochondrial disorders can present with a wide range of clinical and biochemical phenotypes. Mitochondrial DNA variants may be influenced by factors such as degree of heteroplasmy and tissue distribution. We present a four-generation family in which 10 individuals carry a pathogenic mitochondrial variant (m.5537_5538insT, MT-TW gene) with differing levels of heteroplasmy and clinical features. This genetic variant has been documented in two prior reports, both in individuals with Leigh syndrome. In the current family, three individuals have severe mitochondrial symptoms including Leigh syndrome (patient 1, 100% in blood), MELAS (patient 2, 97% heteroplasmy in muscle), and MELAS-like syndrome (patient 3, 50% heteroplasmy in blood and 100% in urine). Two individuals have mild mitochondrial symptoms (patient 4, 50% in blood and 67% in urine and patient 5, 50% heteroplasmy in blood and 30% in urine). We observe that this variant is associated with multiple mitochondrial presentations and phenotypes, including MELAS syndrome for which this variant has not previously been reported. We also demonstrate that the level of heteroplasmy of the mitochondrial DNA variant correlates with the severity of clinical presentation; however, not with the specific mitochondrial syndrome.


Assuntos
Doença de Leigh , Síndrome MELAS , Doenças Mitocondriais , Humanos , Síndrome MELAS/diagnóstico , Síndrome MELAS/genética , Síndrome MELAS/complicações , Doença de Leigh/diagnóstico , Doença de Leigh/genética , Doença de Leigh/complicações , Mitocôndrias/genética , DNA Mitocondrial/genética , Doenças Mitocondriais/diagnóstico , Doenças Mitocondriais/genética , Doenças Mitocondriais/complicações
15.
Orphanet J Rare Dis ; 18(1): 264, 2023 09 04.
Artigo em Inglês | MEDLINE | ID: mdl-37667390

RESUMO

BACKGROUND: Leigh Syndrome (LS) is a rare genetic neurometabolic disorder, that leads to the degeneration of the central nervous system and subsequently, early death. LS can be caused by over 80 mutations in mitochondrial or nuclear DNA. Patient registries are important for many reasons, such as studying the natural history of the disease, improving the quality of care, and understanding the healthcare burden. For rare diseases, patient registries are significantly important as patient numbers are small, and funding is limited. Cure Mito Foundation started a global patient registry for LS in September 2021 to identify and learn about the LS patient population, facilitate clinical trial recruitment, and unite international patients and researchers. Priorities were to allow researchers and industry partners to access data at no cost through a clear and transparent process, active patient engagement, and sharing of results back to the community. RESULTS: Patient registry platform, survey design, data analysis process, and patient recruitment strategies are described. Reported results include demographics, diagnostic information, symptom history, loss of milestones, disease management, healthcare utilization, quality of life, and caregiver burden for 116 participants. Results show a high disease burden, but a relatively short time to diagnosis. Despite the challenges faced by families impacted by Leigh syndrome, participants, in general, are described as having a good quality of life and caregivers are overall resilient, while also reporting a significant amount of stress. CONCLUSION: This registry provides a straightforward, no-cost mechanism for data sharing and contacting patients for clinical trials or research participation, which is important given the recruitment challenges for clinical trials for rare diseases. This is the first publication to present results from a global patient registry for Leigh Syndrome, with details on a variety of patient-specific and caregiver outcomes reported for the first time. Additionally, this registry is the first for any mitochondrial disease with nearly 70% of participants residing outside of the United States. Future efforts include continued publication of results and further collaboration with patients, industry partners, and researchers.


Assuntos
Doença de Leigh , Humanos , Doença de Leigh/genética , Qualidade de Vida , Doenças Raras , Sistema Nervoso Central , Efeitos Psicossociais da Doença
16.
Mov Disord ; 38(12): 2217-2229, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37752895

RESUMO

BACKGROUND: Rare mutations in NADH:ubiquinone oxidoreductase complex assembly factor 5 (NDUFAF5) are linked to Leigh syndrome. OBJECTIVE: We aimed to describe clinical characteristics and functional findings in a patient cohort with NDUFAF5 mutations. METHODS: Patients with biallelic NDUFAF5 mutations were recruited from multi-centers in Taiwan. Clinical, laboratory, radiological, and follow-up features were recorded and mitochondrial assays were performed in patients' skin fibroblasts. RESULTS: Nine patients from seven unrelated pedigrees were enrolled, eight homozygous for c.836 T > G (p.Met279Arg) in NDUFAF5 and one compound heterozygous for p.Met279Arg. Onset age had a bimodal distribution. The early-onset group (age <3 years) presented with psychomotor delay, seizure, respiratory failure, and hyponatremia. The late-onset group (age ≥5 years) presented with normal development, but slowly progressive dystonia. Combing 25 previously described patients, the p.Met279Arg variant was exclusively identified in Chinese ancestry. Compared with other groups, patients with late-onset homozygous p.Met279Arg were older at onset (P = 0.008), had less developmental delay (P = 0.01), less hyponatremia (P = 0.01), and better prognosis with preserved ambulatory function into early adulthood (P = 0.01). Bilateral basal ganglia necrosis was a common radiological feature, but brainstem and spinal cord involvement was more common with early-onset patients (P = 0.02). A modifier gene analysis showed higher concomitant mutation burden in early-versus late-onset p.Met279Arg homozygous cases (P = 0.04), consistent with more impaired mitochondrial function in fibroblasts from an early-onset case than a late-onset patient. CONCLUSIONS: The p.Met279Arg variant is a common mutation in our population with phenotypic heterogeneity and divergent prognosis based on age at onset. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.


Assuntos
Distúrbios Distônicos , Hiponatremia , Doença de Leigh , Transtornos dos Movimentos , Pré-Escolar , Humanos , Distúrbios Distônicos/complicações , Hiponatremia/complicações , Doença de Leigh/genética , Doença de Leigh/complicações , Metiltransferases/genética , Proteínas Mitocondriais/genética , Transtornos dos Movimentos/complicações , Mutação/genética , Criança , Adulto Jovem
17.
Br J Anaesth ; 131(5): 832-846, 2023 11.
Artigo em Inglês | MEDLINE | ID: mdl-37770252

RESUMO

BACKGROUND: Volatile anaesthetics are widely used in human medicine. Although generally safe, hypersensitivity and toxicity can occur in rare cases, such as in certain genetic disorders. Anaesthesia hypersensitivity is well-documented in a subset of mitochondrial diseases, but whether volatile anaesthetics are toxic in this setting has not been explored. METHODS: We exposed Ndufs4(-/-) mice, a model of Leigh syndrome, to isoflurane (0.2-0.6%), oxygen 100%, or air. Cardiorespiratory function, weight, blood metabolites, and survival were assessed. We exposed post-symptom onset and pre-symptom onset animals and animals treated with the macrophage depleting drug PLX3397/pexidartinib to define the role of overt neuroinflammation in volatile anaesthetic toxicities. RESULTS: Isoflurane induced hyperlactataemia, weight loss, and mortality in a concentration- and duration-dependent manner from 0.2% to 0.6% compared with carrier gas (O2 100%) or mock (air) exposures (lifespan after 30-min exposures ∗P<0.05 for isoflurane 0.4% vs air or vs O2, ∗∗P<0.005 for isoflurane 0.6% vs air or O2; 60-min exposures ∗∗P<0.005 for isoflurane 0.2% vs air, ∗P<0.05 for isoflurane 0.2% vs O2). Isoflurane toxicity was significantly reduced in Ndufs4(-/-) exposed before CNS disease onset, and the macrophage depleting drug pexidartinib attenuated sequelae of isoflurane toxicity (survival ∗∗∗P=0.0008 isoflurane 0.4% vs pexidartinib plus isoflurane 0.4%). Finally, the laboratory animal standard of care of 100% O2 as a carrier gas contributed significantly to weight loss and reduced survival, but not to metabolic changes, and increased acute mortality. CONCLUSIONS: Isoflurane is toxic in the Ndufs4(-/-) model of Leigh syndrome. Toxic effects are dependent on the status of underlying neurologic disease, largely prevented by the CSF1R inhibitor pexidartinib, and influenced by oxygen concentration in the carrier gas.


Assuntos
Anestésicos Inalatórios , Isoflurano , Doença de Leigh , Humanos , Animais , Camundongos , Isoflurano/toxicidade , Anestésicos Inalatórios/toxicidade , Doença de Leigh/genética , Oxigênio , Redução de Peso , Complexo I de Transporte de Elétrons
18.
PLoS One ; 18(9): e0291442, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37725617

RESUMO

Increasing evidence demonstrate that the electron transfer chain plays a critical role in controlling the effector functions of macrophages. In this work, we have generated a Ndufs4-/- murine macrophage cell lines. The Ndufs4 gene, which encodes a supernumerary subunit of complex I, is a mutational hotspot in Leigh syndrome patients. Ndufs4-/- macrophages showed decreased complex I activity, altered complex I assembly, and lower levels of maximal respiration and ATP production. These mitochondrial respiration alterations were associated with a shift towards a pro-inflammatory cytokine profile after lipopolysaccharide challenge and improved ability to phagocytose Gram-negative bacteria.


Assuntos
Complexo I de Transporte de Elétrons , Doença de Leigh , Humanos , Animais , Camundongos , Complexo I de Transporte de Elétrons/genética , Macrófagos , Fagocitose , Linhagem Celular
19.
Genes (Basel) ; 14(8)2023 07 27.
Artigo em Inglês | MEDLINE | ID: mdl-37628588

RESUMO

Mitochondrial diseases are the most common inherited inborn error of metabolism resulting in deficient ATP generation, due to failure in homeostasis and proper bioenergetics. The most frequent mitochondrial disease manifestation in children is Leigh syndrome (LS), encompassing clinical, neuroradiological, biochemical, and molecular features. It typically affects infants but occurs anytime in life. Considering recent updates, LS clinical presentation has been stretched, and is now named LS spectrum (LSS), including classical LS and Leigh-like presentations. Apart from clinical diagnosis challenges, the molecular characterization also progressed from Sanger techniques to NGS (next-generation sequencing), encompassing analysis of nuclear (nDNA) and mitochondrial DNA (mtDNA). This upgrade resumed steps and favored diagnosis. Hereby, our paper presents molecular and clinical data on a Portuguese cohort of 40 positive cases of LSS. A total of 28 patients presented mutation in mtDNA and 12 in nDNA, with novel mutations identified in a heterogeneous group of genes. The present results contribute to the better knowledge of the molecular basis of LS and expand the clinical spectrum associated with this syndrome.


Assuntos
Doença de Leigh , Criança , Lactente , Humanos , Doença de Leigh/genética , Portugal , DNA Mitocondrial/genética , Mitocôndrias , Evolução Biológica
20.
Metab Brain Dis ; 38(7): 2489-2497, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37642897

RESUMO

Leigh syndrome (LS) and Leigh-like spectrum are the most common infantile mitochondrial disorders characterized by heterogeneous neurologic and metabolic manifestations. Pathogenic variants in SLC carriers are frequently reported in LS given their important role in transporting various solutes across the blood-brain barrier. SLC19A3 (THTR2) is one of these carriers transporting vitamin-B1 (vitB1, thiamine) into the cell. Targeted NGS of nuclear genes involved in mitochondrial diseases was performed in a patient belonging to a consanguineous Tunisian family with LS and revealed a homozygous c.1264 A > G (p.T422A) variant in SLC19A3. Molecular docking revealed that the p.T422A aa change is located at a key position interacting with vitB1 and causes conformational changes compromising vitB1 import. We further disclosed decreased plasma antioxidant activities of CAT, SOD and GSH enzymes, and a 42% decrease of the mtDNA copy number in patient blood.Altogether, our results disclose that the c.1264 A > G (p.T422A) variant in SLC19A3 affects vitB1 transport, induces a mtDNA depletion and reduces the expression level of oxidative stress enzymes, altogether contributing to the LS phenotype of the patient.


Assuntos
Doença de Leigh , Erros Inatos do Metabolismo , Deficiência de Tiamina , Humanos , Consanguinidade , DNA Mitocondrial/genética , Doença de Leigh/genética , Proteínas de Membrana Transportadoras , Simulação de Acoplamento Molecular , Mutação/genética , Estresse Oxidativo/genética , Tiamina
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