title: Over-expression of PKGIα inhibits hypoxia-induced proliferation, Akt activation, and phenotype modulation of human PASMCs: the role of phenotype modulation of PASMCs in pulmonary vascular remodeling.
abstract: The proliferation of pulmonary artery smooth muscle cells (PASMCs) plays a role in pulmonary vascular remodeling (PVR). Recently, it was shown that vascular smooth muscular cell phenotype modulation is important for their proliferation in other diseases. However, little is known about the role of human PASMC phenotype modulation in the proliferation induced by hypoxia and its molecular mechanism during PVR. In this study, we found using primary cultured human PASMCs that hypoxia suppressed the expression of endogenous PKGIα, which was reversed by transfection with a recombinant adenovirus containing the full-length cDNA of PKGIα (Ad-PKGIα). Ad-PKGIα transfection significantly attenuated the hypoxia-induced downregulation of the expression of smooth muscle α-actin (SM-α-actin), myosin heavy chain (MHC) and calponin in PASMCs, indicating that hypoxia-induced phenotype modulation was blocked. Furthermore, flow cytometry and (3)H-TdR incorporation demonstrated that hypoxia-induced PASMC proliferation was suppressed by upregulation of PKGIα. These results suggest that enhanced PKGIα expression inhibited hypoxia-induced PASMC phenotype modulation and that it could reverse the proliferation of PASMCs significantly. Moreover, our previous work has demonstrated that Akt protein is activated in the process of hypoxia-induced proliferation of human PASMCs. Interestingly, we found that Akt was not activated by hypoxia when PASMC phenotype modulation was blocked by Ad-PKGIα. This result suggests that blocking phenotype modulation might be a key up-stream regulatory target.
authors.affiliation: Department of Anesthesia, Southwest Hospital, the Third Military Medical University, Chongqing 400038, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Yi
authors.forename: Jian
authors.initials: J
authors.lastname: Cui
authors.forename: Jiao-nin
authors.initials: JN
authors.lastname: Ning
authors.forename: Guan-song
authors.initials: GS
authors.lastname: Wang
authors.forename: Gui-sheng
authors.initials: GS
authors.lastname: Qian
authors.forename: Kai-zhi
authors.initials: KZ
authors.lastname: Lu
mesh_terms: D015687:Cell Hypoxia / Q000235:genetics; D049109:Cell Proliferation; D002478:Cells, Cultured; D062965:Cyclic GMP-Dependent Protein Kinase Type I; D017869:Cyclic GMP-Dependent Protein Kinases / Q000378:metabolism*; D006801:Humans; D000860:Hypoxia; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000502:physiology*; D010641:Phenotype; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D011651:Pulmonary Artery / Q000378:metabolism; D014162:Transfection; D015854:Up-Regulation
chemical_list: D051057:Proto-Oncogene Proteins c-akt; D062965:Cyclic GMP-Dependent Protein Kinase Type I; D017869:Cyclic GMP-Dependent Protein Kinases; C569718:PRKG1 protein, human