In vitro characterization of mitochondrial function and structure in rat and human cells with a deficiency of the NADH: ubiquinone oxidoreductase Ndufc2 subunit

• Published in: Human molecular genetics 2017-12, Vol.26 (23), p.4541-4555
• Main Authors: Raffa, Salvatore, Scrofani, Cristina, Valente, Sabatino, Micaloni, Andrea, Forte, Maurizio, Bianchi, Franca, Coluccia, Roberta, Geurts, Aron M, Sciarretta, Sebastiano, Volpe, Massimo, Torrisi, Maria Rosaria, Rubattu, Speranza
• Format: Article
• Language: English
• Subjects: Animals; Electron Transport Complex I - deficiency; Electron Transport Complex I - metabolism; Fibroblasts - enzymology; Fibroblasts - pathology; Fibroblasts - ultrastructure; Humans; Leukocytes, Mononuclear - enzymology; Leukocytes, Mononuclear - metabolism; Metabolism, Inborn Errors - metabolism; Mitochondria - enzymology; Mitochondria - pathology; Mitochondrial Diseases - enzymology; Mitochondrial Proteins - deficiency; Mitochondrial Proteins - metabolism; Oxidation-Reduction; Oxidative Phosphorylation; Oxidative Stress - physiology; Protein Subunits; Rats; Rats, Inbred SHR; Reactive Oxygen Species - metabolism; Stroke - metabolism; Ubiquinone - metabolism
• ISSN: 0964-6906; 1460-2083
• DOI: 10.1093/hmg/ddx333

Ndufc2, a subunit of the NADH: ubiquinone oxidoreductase, plays a key role in the assembly and activity of complex I within the mitochondrial OXPHOS chain. Its deficiency has been shown to be involved in diabetes, cancer and stroke. To improve our knowledge on the mechanisms underlying the increased disease risk due to Ndufc2 reduction, we performed the present in vitro study aimed at the fine characterization of the derangements in mitochondrial structure and function consequent to Ndufc2 deficiency. We found that both fibroblasts obtained from skin of heterozygous Ndufc2 knock-out rat model showed marked mitochondrial dysfunction and PBMC obtained from subjects homozygous for the TT genotype of the rs11237379/NDUFC2 variant, previously shown to associate with reduced gene expression, demonstrated increased generation of reactive oxygen species and mitochondrial damage. The latter was associated with increased oxidative stress and significant ultrastructural impairment of mitochondrial morphology with a loss of internal cristae. In both models the exposure to stress stimuli, such as high-NaCl concentration or LPS, exacerbated the mitochondrial damage and dysfunction. Resveratrol significantly counteracted the ROS generation. These findings provide additional insights on the role of an altered pattern of mitochondrial structure-function as a cause of human diseases. In particular, they contribute to underscore a potential genetic risk factor for cardiovascular diseases, including stroke.