A, Quantification of mRNA expressed in OOX cumulus cells (OOX), OOX cumulus cells treated with GDF9 (OOX+GDF9), GDF9 and SB431542 (OOX+GDF9+SB), or SIS (OOX+GDF9+SIS) for 20 h

A, Quantification of mRNA expressed in OOX cumulus cells (OOX), OOX cumulus cells treated with GDF9 (OOX+GDF9), GDF9 and SB431542 (OOX+GDF9+SB), or SIS (OOX+GDF9+SIS) for 20 h. low in cumulus cells of mutant mice lacking in the creation from the oocyte-derived paracrine elements development differentiation aspect 9 (GDF9) and bone tissue morphogenetic proteins 15 (BMP15). Furthermore, microsurgical removal of oocytes from wild-type COCs decreased appearance of mRNA and proteins significantly, and these levels were restored by either coculture with oocytes or treatment with recombinant GDF9 or GDF9 plus recombinant BMP15. Blocking Sma- and Mad-related protein (SMAD)2/3 phosphorylation inhibited expression in wild-type COCs and in GDF9-treated wild-type cumulus cells, and conditional deletion of and genes in granulosa cells resulted in the reduction of mRNA in cumulus cells. These results indicate that oocytes promote expression of in cumulus cells, and a SMAD2/3-dependent pathway is involved in this process. At least two oocyte-derived growth factors, GDF9 and BMP15, are required for EGFR expression by cumulus cells. In healthy Graafian follicles of mammalian ovaries, oocytes are maintained at immature germinal vesicle stage and form a gap junction-mediated syncytium-like structure with surrounding layers of compact cumulus cells, which is termed the cumulus-oocyte complex (COC). COCs persist at the immature stage until the preovulatory surge of LH induces them to mature. During COC maturation, oocytes undergo germinal vesicle breakdown and resume meiosis, and its surrounding cumulus oophorus undergoes a process called expansion. Expansion involves AV412 cumulus cell production of a sticky mucinous extracellular matrix essential for ovulation, fertilization, and the subsequent embryonic development. Failure to undergo these maturational processes causes female infertility (1,2,3,4). Expression of LH/choriogonadotropin receptors is restricted to theca and mural granulosa cells that line the follicular wall, AV412 and murine cumulus cells or oocytes express no detectable LH/choriogonadotropin receptors (5,6,7). Therefore, the mechanism by which LH induces maturation of COCs in intact follicles was a longstanding puzzle. Recently, however, compelling evidence from studies in mice showed that a locally produced epidermal growth factor (EGF) receptor (EGFR) network within the follicle mediates LH-induced COC maturation (8,9). LH induces a rapid and transient expression of three members of the EGF family of growth factors, (was placed onto the background, creating compound mutants (10). Because AREG binds exclusively to EGFR, the severely impaired maturation of COCs in mice indicates that a functional EGFR network in the follicle, especially the expression of in cumulus cells, is indispensable for the induction of COC maturation and ovulation and, when ovulated using recombinant proteins also demonstrated that both GDF9 and BMP15 are crucial for cumulus expansion (17,19,23,24,25,26). The cumulus expansion enabling effect of mouse oocytes and GDF9 appears to be mediated by a Sma- and Mad-related protein (SMAD; MAD homolog, mRNA and protein levels in cumulus cells. Results expression in cumulus cells from mRNA and protein were significantly lower in both mRNA levels in mRNA and protein in the mutant cumulus cells, levels of phosphorylated SMAD2, a downstream effector of the activated type I receptors (activin receptor-like kinase-4, -5, or -7) for a group of specific TGF superfamily ligands (mRNA expressed in WT-, < 0.05, test. C, EGFR-dependent acute response of WT- and DM-cumulus cells. Freshly isolated WT- and DM-COCs were treated with or without 250 ng/ml AREG for 30 min, indicated as AREG and Control groups, respectively, and the levels of p-MAPK3/1 and total MAPK3/1 were then assayed. D, Quantification of mRNA in WT- and DM-cumulus cells 4 h after hCG injection are significantly different, < 0.05. In C and D, groups denoted with are significantly different from the corresponding WT groups, < 0.05, test. Note that each Western blot image shown is of the Rabbit Polyclonal to EIF3J same membrane sequentially immunoblotted for the proteins indicated. AV412 This applies to all the following figures. Coincident with lower levels of mRNA and protein in DM cumulus cells, the acute response of these cumulus cells to the stimulation of EGFR ligand, AREG, was also.