Rabbit Anti-Human PRKG1 (a.a. 336-631) Polyclonal antibody

Pulmonary arterial hypertension (PAH) is a progressive, usually fatal disease with abnormal vascular remodeling. Pulmonary artery smooth muscle cells (PASMCs) from PAH patients are hyperproliferative and apoptosis-resistant and demonstrate decreased signaling in response to bone morphogenetic proteins (BMPs). Cyclic GMP-elevating agents are beneficial in PAH, but their mechanism(s) of action are incompletely understood. Here we show that BMP signaling via Smad1/5/8 requires cGMP-dependent protein kinase isotype I (PKGI) to maintain PASMCs in a differentiated, low proliferative state. BMP cooperation with cGMP/PKGI was crucial for transcription of contractile genes and suppression of pro-proliferative and anti-apoptotic genes. Lungs from mice with low or absent PKGI (Prkg1(+/-) and Prkg1(-/-) mice) exhibited impaired BMP signaling, decreased contractile gene expression, and abnormal vascular remodeling. Conversely, cGMP stimulation of PKGI restored defective BMP signaling in rats with hypoxia-induced PAH, consistent with cGMP-elevating agents reversing vascular remodeling in this PAH model. Our results provide a mechanism for the therapeutic effects of cGMP-elevating agents in PAH and suggest that combining them with BMP mimetics may provide a novel, disease-modifying approach to PAH therapy.

Cyclic GMP (cGMP)-dependent protein kinase II (Prkg2, cGK II) was identified as a potential target of the progesterone receptor (Nr3c3) in the mouse ovary based on microarray analyses. To document this further, the expression patterns of cGK II and other components of the cGMP signaling pathway were analyzed during follicular development and ovulation using the pregnant mare serum gonadotropin (PMSG)-human chorionic gonadotropin (hCG)-primed immature mice. Levels of cGK II mRNA were low in ovaries of immature mice, increased 4-fold in response to pregnant mare serum gonadotropin and 5-fold more within 12 h after hCG, the time of ovulation. In situ hybridization localized cGK II mRNA to granulosa cells and cumulus oocyte complexes of periovulatory follicles. In progesterone receptor ( PR) null mice, cGK II mRNA was reduced significantly at 12 h after hCG in contrast to heterozygous littermates. In primary granulosa cell cultures, cGK II mRNA was induced by phorbol 12-myristate 13-acetate enhanced by adenoviral expression of PR-A and blocked by RU486 and trilostane. PR-A in the absence of phorbol 12-myristate 13-acetate was insufficient to induce cGK II. Expression of cGK I (Prkg1) was restricted to the residual tissue and not regulated by hormones. Guanylate cyclase-A ( Npr1; GC-A) mRNA expression increased 6-fold by 4 h after hCG treatment in contrast to pregnant mare serum gonadotropin alone and was localized to granulosa cells of preovulatory follicles. Collectively, these data show for the first time that cGK II ( not cGK I) and GC-A are selectively induced in granulosa cells of preovulatory follicles by LH- and PR-dependent mechanisms, thereby providing a pathway for cGMP function during ovulation.