SUN-246 Altered Propionate Metabolism Promotes Aldosterone Production in Aldosterone-Producing Adenomas

Abstract Disclosure: Y. Yang: None. M. Gao: None. Z. Xia: None. Y. Liu: None. Z. Zhang: None. M. Sun: None. Aldosterone-producing adenomas (APAs) are a major cause of primary aldosteronism, characterized by upregulation of CYP11B2 gene transcription (encoding aldosterone synthase) and aldosterone biosynthesis in adrenal zona glomerulosa cells. While alterations in metabolic pathways have been reported in APAs, their roles in aldosterone production remain largely undefined. Here, we identified dysregulated propionate metabolism in APAs compared with adjacent zona glomerulosa by bioinformatic analyses using a publicly available dataset (GSE64957). The levels of methylmalonic acid (MMA), a by-product of propionate metabolism, were upregulated in the venous serum from the ipsilateral side of adrenals compared with the contralateral side in patients with APAs (n=15 pairs). This occurred possibly through the upregulation of propionyl-CoA carboxylase alpha (PCCA) in APAs confirmed by immunoblotting and immunohistochemistry. In human adrenocortical cells (HAC15), overexpression or silencing of PCCA caused upregulation or downregulation of CYP11B2 expression and aldosterone production, respectively. MMA treatment in HAC15 cells or C57BL/6 mice also increased CYP11B2 expression and aldosterone production. RNA sequencing revealed an MMA-induced alteration of calcium signaling in HAC15 cells. The elevation of intracellular calcium concentration was later confirmed in MMA-treated cells, and the stimulatory effect of MMA on CYP11B2 expression was reversible by calcium inhibitor nifedipine and calmodulin kinase II inhibitor KN93. Coherently with previous findings, we identified an elevated reactive oxygen species level following MMA treatment. Given the relationship between reactive oxygen species generation and glutathionylation, and the enrichment of the Gene Ontology term “Glutathione binding” in RNA sequencing, we demonstrated that MMA induced glutathionylation in HAC15 cells. Notably, the glutathionylation of L-type calcium channel Cav1.2, which was reported to regulate intracellular calcium influx, was enhanced by MMA. This effect was reversible by the reactive oxygen species scavenger N-acetylcysteine. Mass spectrometry further confirmed that MMA induced the glutathionylation of Cav1.2 at positions Cysteine 106 and Cysteine 621. Collectively, we present a previously uncharacterized dysregulation of propionate metabolism as an important contributor to aldosterone production via MMA-induced Cav1.2 glutathionylation. This pathway represents a potentially valuable target for the development of new therapeutic strategies for primary aldosteronism. Presentation: Sunday, July 13, 2025