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Researchers identified a rare genetic variant in the OPA1 gene (c.563C>T) in a patient with dilated cardiomyopathy (DCM) and demonstrated that this mutation disrupts mitochondrial structure and function. Laboratory studies showed the mutant protein causes mitochondrial fragmentation, reduced energy production, increased calcium levels and oxidative stress, and activation of cell death pathways. The findings suggest this OPA1 variant contributes to heart disease development by impairing the energy-producing organelles within heart muscle cells.
Why it matters
This research links a specific mitochondrial gene mutation to dilated cardiomyopathy, potentially explaining disease mechanisms in some patients and opening new diagnostic possibilities. The identification of OPA1-mediated mitochondrial dysfunction as a disease pathway suggests potential targets for developing therapies aimed at improving mitochondrial function in heart failure patients.
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⚠️ Preprint – Noch nicht peer-reviewed
Dieser Artikel wurde noch nicht von unabhängigen Experten begutachtet. Die Ergebnisse sind vorläufig und sollten mit Vorsicht interpretiert werden.
Abstract Optic Atrophy 1 (OPA1), an important inner mitochondrial membrane GTPase, regulates mitochondrial fusion, maintains cristae structure, calcium buffering, cellular bioenergetics, preserves mtDNA and controls apoptosis. Here we examined the role of OPA1 variants in DCM using whole-exome sequencing (WES) of 5 familial and 10 sporadic DCM cases. A rare de novo OPA1 variant, c.563C>T (p.Pro188Leu), was identified in a DCM patient, which is absent in 100 healthy controls as well as in the 1000 Genomes, IndiGenomes and GenomeAsia 100k databases while it showed very low MAF (0.000069) in GnomAD. Structural modelling predicted the variant to be highly deleterious and revealed marked conformational distortion of the mutant protein (RMSD = 3.5 Angstrom). Molecular docking further demonstrated enhanced accessibility of mutant OPA1 to mitochondrial protease OMA1, suggesting increased OPA1 proteolytic processing and a consequent increase in mitochondrial fragmentation. Functional analysis in stable H9C2 cardiomyoblast cells, demonstrated significantly reduced OPA1 protein expression, extensive mitochondrial fragmentation in mutant-OPA1 expressing cells. The mutant protein caused significant reduction in mitochondrial membrane potential, ATP generation, and oxygen consumption rate (OCR), together with elevated cytosolic Calcium and reactive oxygen species (ROS) levels. qRT-PCR analysis further revealed depletion in mtDNA copy number and increased in expression of intrinsic apoptotic markers Caspase3, 9 and Bax/Bcl-2 ratio. The above findings collectively highlighted the significant impact of the OPA1 mutation on mitochondrial dynamics and cellular health, suggesting a significant correlation with the pathogenesis of DCM. Collectively, these findings suggest that OPA1-mediated mitochondrial dysfunction represents a potential therapeutic avenue for the management of DCM.