L-Kynurenine activates the AHR-PCSK9 pathway to mediate the lipid metabolic and ovarian dysfunction in polycystic ovary syndrome
Yujiao Wang, Yifan Wu, Hongwei Jiang, Shang Li, Jingjing Li, Cong Wang, Lexin Yang, Xiying Zhou, Juanjuan Yu, Junyu Zhai, Zi‐Jiang Chen, Yanzhi Du
Abstract
Dysregulated amino acid metabolism is a key contributor to polycystic ovary syndrome (PCOS). This cross-sectional study revealed that serum levels of L-kynurenine (L-Kyn) were significantly elevated in women with PCOS, whereas pyridoxal 5'-phosphate (PLP) levels were markedly reduced. Moreover, human serum L-Kyn levels exhibited a positive correlated with low-density lipoprotein cholesterol (LDL-C) and a negative correlation with high-density lipoprotein cholesterol (HDL-C). Additionally, letrozole (LET) induced PCOS-like mice displayed increased hepatic L-Kyn levels. Mechanistically, both in vivo and in vitro experiments demonstrated that the upregulation of indoleamine 2,3-dioxygenase (IDO1) activates the aryl hydrocarbon receptor (AHR) - proprotein convertase subtilisin/kexin type 9 (PCSK9) pathway in the liver of PCOS-like mice, thereby contributing to dyslipidemia. Treatment with epacadostat, an inhibitor of the enzyme IDO1, or PLP, a cofactor for L-Kyn catabolism, effectively restored ovarian function, improved glucose tolerance, and ameliorated lipid profile abnormalities in PCOS-like mice.