Peptide YY fragment PYY1-36 disrupts mitochondrial biogenesis via RBM43-dependent PGC-1α translation inhibition.

Mitochondrial dysfunction is a key driver of cancer progression, with therapies increasingly targeting metabolic weaknesses. Peptide YY (PYY), a gastrointestinal hormone, regulates cellular activity, but its influence on mitochondrial health in lung cancer remains poorly understood. We explored how PYY1-36, a bioactive fragment of PYY, affects mitochondrial stability in NCI-H1581 lung cancer cells. Using dose-response experiments, we measured oxidative stress by tracking lactate dehydrogenase (LDH) release, mitochondrial ROS levels, and oxidative DNA damage (8-OHdG). Energy production was evaluated through ATP levels, oxygen consumption rates (OCR), and Complex I activity. We also analyzed mitochondrial biogenesis markers (NRF1, TFAM, PGC-1α) and the RNA-binding protein RBM43 via qPCR and immunoblotting. Dose-dependent tests showed that PYY1-36 triggers mitochondrial oxidative damage, marked by higher LDH release and ROS spikes. These changes aligned with sharp drops in ATP production and disrupted respiratory function. Notably, PYY1-36 reduced mitochondrial mass and biogenesis, supported by weaker MitoTracker Red signals and lower mtDNA/nDNA ratios. Key regulators NRF1 and TFAM were strongly suppressed, pointing to widespread mitochondrial failure. Intriguingly, PYY1-36 blocked PGC-1α protein synthesis without altering mRNA levels, suggesting a post-transcriptional control mechanism. PYY1-36 also boosted RBM43 levels. Knocking down RBM43 reversed PYY1-36's effects on PGC-1α and mitochondrial health. Our findings reveal RBM43 as a central player in PYY1-36-induced mitochondrial dysfunction through its suppression of PGC-1α translation. Targeting RBM43 could unlock new strategies to tackle metabolic chaos in lung cancer.