UTP or higher concentrations of UDP also induced the phosphorylation of MAPK p44 and p42. at substantial concentrations, UDP acted principally on the P2Y2 receptor, considering the fact that P2Y6 is stimulated PI3Kα inhibitor by UDP inside the low uM assortment. Phosphorylation of MAPK was inhibited by suramin, a potent antagonist for P2Y2 and weak for P2Y6, but it was not affected by PPADS, which can be inactive toward P2Y2 but capable to antagonize P2Y6 activa tion. Taken collectively, our data indicated a principal function on the P2Y2 receptor in MAPK activation. There is ample proof that these protein kinases are involved while in the proliferative phenomenon activated by G protein cou pled receptors in various cell methods ]. moreover, p44 and p42 MAPK activation dependent on P2Y2 or P2Y6 receptors has become described, e. g, in gran ulosa luteal cells, glioma cells, and embryonic stem cells.
Staurosporin or long lasting incuba tion with PMA blocked UTP induced p44 and p42 MAPK phosphorylation. Additionally, p44 and p42 MAPK phosphorylation was blocked in BAPTA loaded cells, strongly suggesting that a calcium dependent PKC par ticipates in this response. Activation of MAPK p44 and p42 is directly related to induction of cell proliferation. Our kinase inhibitor Sotrastaurin outcomes demon strated that UTP and UDP induced a robust proliferative response just like that of 10% FBS used as good con trol. ATP induced a proliferative response at 10 uM, but no effect was observed with increased concentrations. This supports the idea that P2Y2 is the main receptor involved inside the response, but an ancillary participation of P2Y6 cannot nevertheless be e cluded.
The regulation of theca cell professional liferation is relevant during folliculogenesis, and it could be involved in pathological processes, such as the altered androgen estrogen stability associated with poly cystic ovary Abexinostat syndrome, a typical sickness characterized by uncontrolled theca cell proliferation. On this con te t, purinergic signaling can activate a feedback mecha nism by inducing a proliferative or an apoptotic response in TIC. ATP actions to stimulate TIC proliferation by way of P2Y2 receptor activation need to be taken into consideration, along with the effects described for other neurotransmitters that appear to regulate particular pro cesses within the ovary. For e ample, previous evidence showed that human granulosa luteal cells e press M1 and M5 muscarinic receptors also as P2Y2 purinergic receptors, stimulation of either process by acetyl choline or ATP can market granulosa luteal cell prolif eration. Stimulation of B adrenergic receptors also modulates steroidogenic action and ovulation and, provided that neurotransmitters launched from cate cholaminergic terminals could possibly consist of ATP, it might be of curiosity to learn the result of activating purinergic receptors in these processes.