Disruption of Mitochondrial Dynamics and Integrity Drives Divergent Metabolic Flexibility and Resilience in Podocytes

Mitochondrial dysfunction is central to the pathogenesis of podocytopathies, yet the determinants of metabolic resilience versus failure remain elusive. We investigated how distinct disruptions of mitochondrial architecture, specifically hyperfusion via OMA1 deletion versus compromised inner mitochondrial membrane (IMM) integrity via PHB2 knockdown, influence the metabolic fate and insulin responsiveness of podocytes. To this end, we analyzed conditionally immortalized mouse podocytes with genetic OMA1 deletion or inducible PHB2 knockdown and employed an integrated approach combining bioenergetic studies, quantitative proteomics, phosphoproteomics, metabolomics, and stable isotope tracing studies with ¹³C₆-glucose and ¹³C₅-glutamine. We characterized metabolic remodeling at baseline and after insulin treatment and uncovered profoundly divergent metabolic states. OMA1 deficiency conferred robust metabolic resilience, characterized by a compensatory glycolytic shift and remodeling of TCA cycle flux through glutamine-driven anaplerosis while maintaining oxidative phosphorylation. OMA1-deficient podocytes sustained bioenergetic homeostasis upon insulin challenge by flexibly rerouting carbon flux, including the GABA shunt. In contrast, PHB2 deficiency led to metabolic failure, impaired respiration, and anaplerotic insufficiency. While maintaining basal ATP levels at baseline, PHB2-deficient podocytes exhibited energetic collapse upon insulin treatment, revealing profound metabolic inflexibility. Taken together, the structural integrity of the inner mitochondrial membrane, rather than mitochondrial morphology per se, is a driving determinant of metabolic competence and resilience in podocytes.