The Cisd gene family modulates physiological development and mitochondria function in Caenorhabditis elegans

Objective Caenorhabditis elegans (C. elegans) was employed as a model organism to investigate the physiological role of CISD-3.1 in nematode growth, development, and mitochondrial function. This study aims to provide insights into the conserved functions of the mitochondrial NEET protein Miner2 in human mitochondria. Methods Cisd-3.1 depletion was achieved through RNA interference (RNAi) using the L4440 plasmid, with the recombinant HT115 strain verified by qRT-PCR (empty L4440 vector served as the control). Growth curves, fecundity, and lifespan assays were conducted using the N2 wild-type strain, while the XY1054 strain was utilized to examine the role of cep-1 in development and growth under cisd-3.1 knockdown. Body fat content was quantified using Oil Red O staining, and fat synthesis was assessed through pharyngeal pumping assays and lipid analysis in the VC8 strain. Mitochondrial function and fat breakdown situation were evaluated by measuring membrane potential, reactive oxygen species (ROS), superoxide levels, adenosine triphosphate (ATP)production, mitochondrial DNA copy number, heat shock protein expression, and resistance to high-concentration paraquat (PQ). Results A 70% reduction in CISD-3.1 expression via RNAi led to growth and developmental arrest in nematodes over two consecutive generations, independent of cep-1 . CISD-3.1 depletion significantly reduced fecundity and caused abnormal fat accumulation through the JNK-mediated lipogenesis pathway, without affecting food intake. Mitochondrially, CISD-3.1 knockdown increased membrane potential, decreased ROS levels, and enhanced the oxygen-dependent mitochondrial unfolded protein response (UPR ^mt ). Additionally, ATP synthesis was impaired, and nematodes exhibited increased sensitivity to PQ, although mitochondrial copy number remained unchanged. Conclusion These findings demonstrate that the mitochondrial NEET protein CISD-3.1 in C. elegans plays a critical role in maintaining energy homeostasis and lipid metabolism, offering valuable insights into the conserved functions of Miner2 in human mitochondrial physiology.