Novel Serum Biomarkers Detected by Protein Array in Polycystic Ovary Syndrome with Low Progesterone Level

Polycystic ovary syndrome (PCOS), characterized by female infertility and metabolic abnormalities, is one of the most common endocrine disorders. The etiology of PCOS remains unknown. The comprehensive analysis of protein alterations in PCOS patients is meaningful for identifying diagnostic biomarkers of PCOS. Here, we explored the clinical value of serum proteins as novel biomarkers to detect PCOS with low progesterone level.

A total of 43 patients with PCOS and 30 healthy women were enrolled. Protein array was used to detect the variations of serum proteins between PCOS patients and healthy women. The level of five serum proteins was further confirmed by ELISA and western blot. The human ovarian granulosa cells (KGN) was cultured to examine the underlying mechanism of PCOS. CCK8 assay and western blot were carried out to evaluate the alterations in proliferative ability, TUNEL assay and DAPI staining to detect the apoptosis of KGN cells.

Among the 507 proteins, we identified 76 differentially expressed serum proteins (≧1.5 fold), with 40 elevated and 36 decreased proteins. Moreover, 47 proteins were newly reported in PCOS. The alterations in the five significantly decreased proteins (EREG, inhibin βA, IDE, PDGF-D and KNG1) were further confirmed by ELISA and western blot. The level of these proteins were directly associated with the low progesterone, and the expression could be upregulated by progesterone. EREG and inhibin βA also promoted the proliferation and inhibited the apoptosis of ovarian granulosa cells.

The study highlights that serum proteins are differentially expressed in PCOS patients and healthy women, and EREG and inhibin βA levels are upregulated by progesterone, which are correlated with ovarian functions. The study suggests that EREG and inhibin βA may be applied as novel potential biomarkers for PCOS with low progesterone level.