The Ras family members follow the blood progesterone level during formation and regression in bovine corpus luteum

Abstract

40Ras family members regulate cellular differentiation, proliferation and survival. CL formation and regression are 41 regulated by the blood P4 level. This study investigated the association between changes in Ras family members and 42 the serum P4 level and determined protein interactions among Ras family members, hormone receptors, and 43 angiogenetic and apoptotic factors during formation and regression of the bovine CL. RASAL3 and RASA3 were found 44 using proteomics in CL and were significantly increased in the SPCL compared to the PPCL, whereas RasGEF1B was 45 decreased in the PPCL. Hormone receptors and angiogenetic proteins expression was lower in the PPCL and SPCL than 46 that in the RPCL, but apoptotic proteins were increased in the RPCL. The P4 and estrogen receptors positive correlated 47 48 Ras protein expression was increased in the PPCL compared to that in the SPCL, whereas RasGEF expression was 49 decreased. In summary, Ras activation and angiogenesis in the CL were positively correlated with the blood P4 during 50 estrous cylce. These results may increase understanding of Ras biological functions following stimulation of hormones 51 and their receptors during tissue proliferation and degeneration. 53The corpus luteum (CL) is a transient endocrine gland in the female reproductive tract that produces progesterone 78 (P4), which is required to maintain pregnancy for the beginning of life in mammals (1). During CL formation, granulosa 79 and theca cells in the ovary are differentiated and proliferate into steroidogenic luteal cells (LSCs) in response to 80 luteinizing hormone (LH) until day 8 to 9 after ovulation. Then, the CL weight increases three to four times when its 81 growth is complete prior to the next round of ovulation (2). LSCs produce P4 that is secreted into the blood vessels, 82 which contribute to the maintenance of pregnancy (3-5). However, if the pregnancy is not established, the CL begins to 83 regress in response to prostaglandin F2 alpha (PGF2α) derived from the endometrium in a process termed luteolysis (6). 84The formation and regression of the CL are repeated, and this repetition by sex hormones distinguishes it from other 85 mammalian tissues (6). For several decades, studies have mainly investigated the formation and regression of 86 gonadotropin release hormone (GnRH) and steroidogenic hormones, whereas few studies have investigated the roles of 87 small GTPases in formation and regression of the CL. 88During the proliferation phase (PP), luteal endothelial cells (LECs) proliferate following interaction with vascular 89 endothelial growth factor A (VEGFA) and VEGF receptor 2 (VEGFR2) to generate blood vessels and support LSC 90 proliferation in the CL (7, 8). After vasculature is stabilized by the balance of angiopoietin 1 (Ang1) and Tie2 (9). When 91 the CL is completely developed, P4 is converted from pregneolone by 3β-hydroxysteroid dehydrogenase (3β-HSD) 92 continuously during a phase that is called the secretion phase (SP) (6). If implantation is successful, matern...