Variants in the HMG-CoA reductase (HMGCR) gene influence component phenotypes in polycystic ovary syndrome

Causal association between lipid-lowering drugs and female reproductive endocrine diseases: a drug-targeted Mendelian randomization study

Purpose

The relationship between dyslipidemia and female reproductive endocrine diseases has been increasingly studied. The use of lipid-lowering drugs in treating various related diseases, including coronary heart disease, may affect female reproductive endocrine diseases. Therefore, our study aims to investigate the effects of lipid-lowering drugs on female reproductive endocrine diseases and provide a basis for the appropriate selection of drugs.

Methods

In this study, we focused on three drug targets of statins, namely HMG-CoA reductase (HMGCR) inhibitors, proprotein convertase kexin 9 (PCSK9) inhibitors, and Niemann-Pick C1-Like 1 (NPC1L1) inhibitors. To identify potential inhibitors for these targets, we collected single nucleotide polymorphisms (SNPs) associated with HMGCR, PCSK9, and NPC1L1 from published genome-wide association study statistics. Subsequently, we conducted a drug target Mendelian randomization (MR) analysis to investigate the effects of these inhibitors on reproductive endocrine diseases mediated by low-density lipoprotein cholesterol (LDL-C) levels. Alongside coronary heart disease as a positive control, our main outcomes of interest included the risk of polycystic ovary syndrome (PCOS), premature ovarian insufficiency (POI), premenstrual syndrome (PMS), abnormal uterine bleeding (including menorrhagia and oligomenorrhea), and infertility.

Results

PCSK9 inhibitors significantly increased the risk of infertility in patients (OR [95%CI] = 1.14 [1.06, 1.23], p<0.05). In contrast, HMGCR inhibitors significantly reduced the risk of menorrhagia in female patients (OR [95%CI] = 0.85 [0.75, 0.97], p<0.05), but had no statistical impact on patients with oligomenorrhea.

Conclusion

The findings suggest that PCSK9 inhibitors may significantly increase the risk of infertility in patients. On the other hand, HMGCR inhibitors could potentially offer protection against menorrhagia in women. However, no effects of lipid-lowering drugs have been observed on other reproductive endocrine disorders, such as PCOS, POF, PMS and oligomenorrhea.

Identification of risk for ovarian disease enhanced by BPB or BPAF exposure

The ban on bisphenol A (BPA) has led to a rapid increase in the use of BPA analogs, and they are increasingly being detected in the natural environment and biological organisms. Studies have pointed out that BPA analogs can lead to adverse health outcomes. However, their interference with ovarian tissue has not been fully elucidated. In this study, seven- to eight-week-old CD-1 mice were exposed to corn oil containing 300 μg/kg/day bisphenol B (BPB) or bisphenol AF (BPAF) through oral gavage, and ovarian tissues were collected at 14 and 28 days of exposure. Ovarian toxicity was evaluated by the ovarian index, ovarian area, and follicle number. mRNA-seq was used to identify differentially expressed genes (DEGs) and infer the association of DEGs with ovarian diseases. BPB or BPAF exposure induced morphological changes in ovarian tissue in CD-1 mice. In addition, Gene Ontology (GO) analysis revealed disturbances in biological processes (BP) associated with steroid biosynthetic process (GO:0006694) and cellular calcium ion homeostasis (GO:0006874). Subsequently, regulatory networks of BPA analogs (BPB or BPAF)-DEGs-ovarian diseases were constructed. Importantly, the expression levels of DEGs and transcription factors (TFs) associated with ovarian disease were altered. BPB or BPAF exposure causes damage to ovarian morphology through the synergistic effects of multiple biological processes and may be associated with altered mRNA expression profiles as a risk factor for ovarian diseases.

Effects of Androgen Excess-Related Metabolic Disturbances on Granulosa Cell Function and Follicular Development

Polycystic ovary syndrome (PCOS) is a common reproductive endocrine disease in women of reproductive age. Ovarian dysfunction including abnormal steroid hormone synthesis and follicular arrest play a vital role in PCOS pathogenesis. Hyperandrogenemia is one of the important characteristics of PCOS. However, the mechanism of regulation and interaction between hyperandrogenism and ovulation abnormalities are not clear. To investigate androgen-related metabolic state in granulosa cells of PCOS patients, we identified the transcriptome characteristics of PCOS granulosa cells by RNA-seq. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis of differentially expressed genes (DEGs) revealed that genes enriched in lipid metabolism pathway, fatty acid biosynthetic process and ovarian steroidogenesis pathway were abnormally expressed in PCOS granulosa cells in comparison with that in control. There are close interactions among these three pathways as identified by analysis of the protein-protein interaction (PPI) network of DEGs. Furthermore, in vitro mouse follicle culture system was established to explore the effect of high androgen and its related metabolic dysfunction on follicular growth and ovulation. RT-qPCR results showed that follicles cultured with dehydroepiandrosterone (DHEA) exhibited decreased expression levels of cumulus expansion-related genes (Has2, Ptx3, Tnfaip6 and Adamts1) and oocyte maturation-related genes (Gdf9 and Bmp15), which may be caused by impaired steroid hormone synthesis and lipid metabolism, thus inhibited follicular development and ovulation. Furthermore, the inhibition effect of DHEA on follicle development and ovulation was ameliorated by flutamide, an androgen receptor (AR) antagonist, suggesting the involvement of AR signaling. In summary, our study offers new insights into understanding the role of androgen excess induced granulosa cell metabolic disorder in ovarian dysfunction of PCOS patients.