Progesterone Activates a Progesterone Receptor Membrane Component 1-Dependent Mechanism That Promotes Human Granulosa/Luteal Cell Survival But Not Progesterone Secretion

Abstract

Objective: We performed this study to test the hypothesis that variation in the lamin a/c gene (LMNA) contributes to milder phenotypes of insulin resistance, hyperandrogenism, and/or metabolic syndrome associated with polycystic ovary syndrome (PCOS). Research Design and Methods: We resequenced the coding region, flanking intronic, and proximal promoter regions of the lamin a/c gene in 43 women with PCOS with evidence of upper-body obesity (waist circumference 88 cm) and identified 56 variants, two of which were nonsynonymous substitutions (lmna11 exon1 E98D; lmna24 exon 7 R455C). We genotyped 53 single-nucleotide polymorphisms (44 identified through resequencing and nine included to maximize informativeness of the entire gene) in 624 index (PCOS) cases and 544 controls of European ancestry. We tested for association between these variants and PCOS. In a subset of individuals, we also tested for association with metabolic syndrome and quantitative traits (body mass index, waist circumference, total testosterone, dehydroepiandrosterone sulfate, fasting glucose and insulin, low-density lipoprotein, and TTG). Results: After correction for multiple testing, none of the variants showed significant evidence for association with PCOS, the metabolic syndrome, or any of the quantitative traits tested. Conclusions: Whereas these studies cannot exclude the role of genetic variation in the lamin a/c gene in isolated cases of PCOS, we can conclude that common variation in the lamin a/c gene does not contribute to the etiology of PCOS in women of European ancestry. Progesterone Activates a Progesterone Receptor Membrane Component 1-Dependent Mechanism That Promotes Human Granulosa/Luteal Cell Survival But Not Progesterone Secretion John J. Peluso, Xiufang Liu, Anna Gawkowska, and Erika Johnston-MacAnanny (J Clin Endocrinol Metab, published May 5, 2009, 10.1210/jc.2009-0147) ABSTRACT Context: Progesterone (P4) promotes its own secretion and the survival of human granulosa/luteal (GL) cells.Context: Progesterone (P4) promotes its own secretion and the survival of human granulosa/luteal (GL) cells. Objective: The objective of these studies was to determine whether progesterone receptor membrane component-1 (PGRMC1) mediates P4’s actions. Design: In vitro studies were conducted on GL cells from women undergoing in vitro fertilization and GL5 cells, which are derived from GL cells. Setting and Patients: GL cells were obtained from women undergoing fertility treatment at a university-based clinic and used for in vitro studies. Main Outcome Measures: PCR, Western blot, and immunocytochemistry were used to detect various progestin binding proteins. H-P4 binding kinetics were assessed on partially purified PGRMC1. Apoptosis was determined after culture by either TUNEL or DAPI staining. P4 was measured by an ELISA assay. PGRMC1 was depleted using small interfering RNA. Results: GL and GL5 cells expressed several P4 binding proteins including the nuclear progesterone receptor (PGR), progestin/ adipoQ receptors (PAQR 7, 8, and 5) and PGRMC1. Ligand binding studies revealed that both P4 and the progestin, R5020, bound PGRMC1 with an EC50 of approximately 10 nM. Interestingly, P4 inhibited apoptosis at concentrations in the 10 nM range, whereas R5020 stimulated P4 secretion at concentrations of at lease 16 M. Depleting PGRMC1 attenuated P4’s antiapoptotic action but failed to influence R5020-induced P4 secretion. T R A N S L A T I O N A L H I G H L I G H T S F R O M J C E M