Long noncoding RNAs – Potential regulators involved in the pathogenesis of polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is the most common cause of anovulatory infertility in women of reproductive age, and its etiology remains poorly understood. Altered activities of long noncoding RNAs (lncRNAs) have been associated with human diseases and development. However, the roles of lncRNAs are unknown in reproductive medicine. Researchers from the Southern Medical University investigated the potential role of lncRNAs in the pathogenesis of PCOS, using human granulosa cells (GCs) and the KGN cell line. They used microarrays to compare lncRNA expression profiles in GCs from 7 PCOS patients and 7 matched women. GC samples were collected during 2014-2016 from infertile women in Guangzhou, China. Quantitative real-time PCR was used to measure levels of the lncRNA HCG26 in GCs from 53 PCOS patients and 50 controls. HCG26 was knocked down with locked nucleic acid GapmaRs in KGN cells to examine the role of HCG26 in cell proliferation, aromatase and FSH receptor gene expression, and estradiol production. A total of 862 lncRNA transcripts and 998 mRNA transcripts were differentially expressed (≥ 2.0-fold change, P < 0.05) in the PCOS GCs compared with controls. HCG26 levels were up-regulated in PCOS patients and associated with antral follicle count. HCG26 knockdown in KGN cells inhibited cell proliferation and cell-cycle progression and increased aromatase gene expression and estradiol production. This study first reported the lncRNA profiles in GCs from PCOS patients and healthy women and suggested that dysregulated lncRNAs may play vital roles in GC proliferation and steroidogenesis, providing new insights into the pathogenesis of PCOS.

Hierarchical clustering map and qRT-PCR validation of lncRNAs and mRNAs

(A) The differentially expressed lncRNAs in granulosa cells from PCOS patients compared with those from healthy women (≥ 2.0-fold; P< 0.05) were analyzed using hierarchical clustering. A1–7 represent PCOS patients 1–7, and C1-7 represent controls. (B and C) The differential expression of lncRNAs and mRNAs: comparison of microarrays with qRT-PCR results. Twelve differentially expressed lncRNAs and eight mRNAs were validated by qRT-PCR (P < 0.05). The Y-axis indicates the fold changes (PCOS/control). The blue bars represent the fold change in the mean expression level (array, n = 7 vs. 7) of granulosa cells between PCOS and control women, whereas the red bars represent the fold change in the mean expression level(qRT-PCR, n= 10 vs. 10) of granulosa cells between PCOS and control women.