Single-cell transcriptomics uncovering a critical AKT-LONP1-STAR axis in ovarian hyperandrogenism of PCOS.

backgroundPolycystic ovary syndrome (PCOS), a prevalent endocrine-metabolic disorder affecting reproductive-aged women worldwide, is characterized by oligo-/anovulation, hyperandrogenism, and polycystic ovarian morphology. Despite affecting 6 ~ 20% of women globally, the molecular mechanisms driving PCOS pathogenesis remain poorly understood, hindering the development of targeted therapeutic strategies.

methodsTo delineate the cellular basis of PCOS pathophysiology, we employed single-cell RNA sequencing (scRNA-seq) data from ovarian theca cells and oocytes of normo-ovulatory controls and PCOS patients. Cellular heterogeneity was systematically mapped using unsupervised clustering, followed by differential expression analysis, pathway enrichment, and pseudotemporal trajectory reconstruction. Key findings were validated in a prenatal dihydrotestosterone-induced murine PCOS model and in vitro theca-interstitial cell cultures treated with AKT activator SC79.

resultsscRNA-seq identified seven distinct theca cell clusters. PCOS patients exhibited an expanded proportion of theca cells expressing steroidogenic acute regulatory protein (STAR), correlating with elevated androgen production, heightened oxidative stress pathway activity, and diminished PI3K-AKT signaling. Oocytes from PCOS patients also showed increased oxidative stress markers. Pathway enrichment indicated impaired oocyte differentiation and development. Pseudotime trajectory analysis of theca cells revealed altered gene expression patterns linked to AKT signaling, oxidative stress, and androgenesis. Integrative analyses uncovered a novel pathogenic axis: reduced AKT signaling downregulates mitochondrial protease LONP1, impairing mitochondrial homeostasis. This LONP1 deficiency elevates STAR expression, promoting oxidative stress and hyperandrogenemia. Consistent with these findings, ovaries from prenatal androgenized PCOS mice exhibited significantly reduced AKT3 and LONP1 expression alongside elevated STAR expression. Mechanistically, in vitro activation of AKT by SC79 in theca-interstitial cells significantly increased LONP1 protein levels and concurrently decreased STAR protein expression.

conclusionsThis study identifies a novel pathogenic axis in PCOS where reduced PI3K-AKT signaling downregulates the mitochondrial protease LONP1, and elevated STAR expression may driving hyperandrogenism in ovarian theca cells. These findings, revealed by scRNA-seq in human patients and validated in a prenatal androgenized mouse model and human theca cell cultures, demonstrate that AKT activation rescues LONP1 levels and suppresses STAR. Thus, targeting the AKT-LONP1-STAR pathway presents a promising therapeutic strategy for PCOS.