Identifying the key role of mitochondrial respiration and lipid metabolism in regulating axillary osmidrosis through proteomics analysis.

Axillary osmidrosis (AO) affects a large number of young people in Asia, resulting from a combination of body and bacterial metabolism. This study aimed to explore the pathogenesis of AO through proteomics. Apocrine gland tissues from 3 mild and 3 severe AO patients were analyzed using 4D label-free proteomics, followed by bioinformatics analysis. The RNA and protein levels of the predicted key regulators were further validated by qPCR and immunohistochemistry in additional AO tissues. A total of 5066 proteins were identified, of which 323 were significantly upregulated and 412 were downregulated (by |log2FC|> 1 and p < 0.05). GO terms related to mitochondria, oxidation-reduction processes, and peroxisomes were significantly enriched among the upregulated DEPs, suggesting enhanced energy metabolism in severe AO patients. Downregulated DEPs were enriched in ribosome, phagosome, and platelet activation pathways according to KEGG, while upregulated DEPs were significantly enriched in metabolic pathways, valine, leucine, and isoleucine degradation, peroxisomes, and fatty acid degradation. The enriched pathways suggest that apocrine gland tissues develop AO by increasing blood flow to promote sweating and secreting excessive short-chain fatty acids by coupling mitochondrial respiration with incomplete metabolism of lipids and branched-chain amino acids. This metabolic coupling may have implications for studies on cardiovascular disease, metabolic disorders, and oxidative stress. Key proteins in the signaling network were further confirmed by qPCR and immunohistochemistry, including reduced FGA and ITGA2B, and increased EHHADH and ACOX1. Our proteomics analysis suggests a paradigm of lipid metabolism involving mitochondrial respiration and incomplete lipid and branched-chain amino acid metabolism as the pathogenesis of AO. We also suggest that EHHADH is a key regulator in promoting AO in this process.