Small glutamine-rich tetratricopeptide repeat-containing protein alpha is present in human ovaries but may not be differentially expressed in relation to polycystic ovary syndrome

Abstract

<h4>Objective</h4>To evaluate the expression and function of small glutamine-rich tetratricopeptide repeat-containing protein alpha (SGTA), an androgen receptor (AR) molecular chaperone, in human ovarian tissues.<h4>Design</h4>Examine the effect of SGTA on AR subcellular localization in granulosa tumor cells (KGN) and SGTA expression in ovarian tissues.<h4>Setting</h4>University-based research laboratory.<h4>Patient(s)</h4>Archived tissues from premenopausal women and granulosa cells from infertile women receiving assisted reproduction.<h4>Intervention(s)</h4>None.<h4>Main outcome measure(s)</h4>AR subcellular localization and SGTA protein or mRNA levels.<h4>Result(s)</h4>SGTA and AR proteins were expressed in the cytoplasm of KGN cells and exposure to androgen stimulated AR nuclear localization. SGTA protein knockdown increased AR nuclear localization at low (0-0.1 nmol/L) but not high (1-10 nmol/L) concentrations of androgen hormone. In ovarian tissues, SGTA was localized to the cytoplasm of granulosa cells at all stages of folliculogenesis and in thecal cells of antral follicles. SGTA protein levels were similar when comparing primordial and primary follicles within core biopsies (n = 40) from women with and without polycystic ovary syndrome (PCOS). Likewise, SGTA mRNA levels were not significantly different in granulosa cells from preovulatory follicles after hyperstimulation of women with and without PCOS.<h4>Conclusion(s)</h4>SGTA is present in human ovaries and has the potential to modulate AR signalling, but it may not be differentially expressed in PCOS.