Autor(es)

Francisco, Annelise ; Goler, Ayse Mine Yilmaz ; Navarro, Claudia Daniele Carvalho ; Onder, Asan ; Yildiz, Melek ; Kendir Demirkol, Yasemin ; Karademir Yilmaz, Betul ; Seven Menevse, Tuba ; Guran, Tulay ; Castilho, Roger Frigerio

• Tipo de documento: Artigo Científico
• Fonte: EUROPEAN JOURNAL OF ENDOCRINOLOGY; v. 190, n. 2, p. 9-pg., 2024-02-07.

Resumo

Background: Pathogenic variants in the nicotinamide nucleotide transhydrogenase gene (NNT) are a rare cause of primary adrenal insufficiency (PAI), as well as functional impairment of the gonads. Objective: Despite the description of different homozygous and compound heterozygous NNT variants in PAI patients, the extent to which the function and expression of the mature protein are compromised remains to be clarified. Design: The activity and expression of mitochondrial NAD(P)(+) transhydrogenase (NNT) were analyzed in blood samples obtained from patients diagnosed with PAI due to genetically confirmed variants of the NNT gene (n = 5), heterozygous carriers as their parents (n = 8), and healthy controls (n = 26). Methods: NNT activity was assessed by a reverse reaction assay standardized for digitonin-permeabilized peripheral blood mononuclear cells (PBMCs). The enzymatic assay was validated in PBMC samples from a mouse model of NNT absence. Additionally, the PBMC samples were evaluated for NNT expression by western blotting and reverse transcription quantitative polymerase chain reaction and for mitochondrial oxygen consumption. Results: NNT activity was undetectable (<4% of that of healthy controls) in PBMC samples from patients, independent of the pathogenic genetic variant. In patients' parents, NNT activity was approximately half that of the healthy controls. Mature NNT protein expression was lower in patients than in the control groups, while mRNA levels varied widely among genotypes. Moreover, pathogenic NNT variants did not impair mitochondrial bioenergetic function in PBMCs. Conclusions: The manifestation of PAI in NNT-mutated patients is associated with a complete lack of NNT activity. Evaluation of NNT activity can be useful to characterize disease-causing NNT variants. (AU)

• Processo FAPESP: 19/20855-7 - Papel da NAD(P)-Transidrogenase mitocondrial no desenvolvimento da Doença Hepática Gordurosa e no envelhecimento
• Beneficiário: Claudia Daniele Carvalho Navarro
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
• Processo FAPESP: 20/05202-4 - Papel da NAD(P)+ transidrogenase mitocondrial na neurotransmissão monoaminérgica e neurodegeneração em camundongos
• Beneficiário: Annelise Francisco
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
• Processo FAPESP: 17/17728-8 - Função e disfunção mitocondrial: implicações para o envelhecimento e doenças associadas
• Beneficiário: Aníbal Eugênio Vercesi
• Modalidade de apoio: Auxílio à Pesquisa - Temático