[Calcineurin/NFAT signaling pathway mediates endothelin-1-induced pulmonary artery smooth muscle cell proliferation by regulating phosphodiesterase-5].
OBJECTIVE
To examine whether calcineurin/NFAT signaling pathway mediates endothelin-1 (ET-1)-induced proliferation of pulmonary artery smooth muscle cells (PASMCs) by regulating phosphodiesterase-5 (PDE5) and the effect of the selective calcineurin inhibitor cyclosporine A and PDE5 inhibitor sildenafil on ET-1-induced PASMC proliferation.


METHODS
PASMCs were treated with ET-1 to stimulate their proliferation with or without prior treatment of the cells with CsA or sildenafil. Calcineurin activity in the cells was measured using a calcineurin activity assay kit, PDE5 expression examined using immunoblotting, and cGMP level detected using a cGMP direct immunoassay kit. PASMC proliferation following the treatments was determined using [(3)H]thymidine incorporation assay.


RESULTS
ET-1 caused a 2.05-fold increase in the cellular calcineurin activity, a 1.80-fold increase in PDE5 expression, and a 3.20-fold increase in the DNA synthesis rate, and reduced the cGMP level by 67%. Pretreatment of the cells with Cyclosporine blocked the effects of ET-1, and PDE5 inhibition by sildenafil pretreatment also abolished ET-1-induced reduction of cGMP level in the cells. Both Cyclosporine and sildenafil suppressed ET-1-stimulated PASMC proliferation.


CONCLUSIONS
Activation of calcineurin/NFAT signaling pathway mediates ET-1-induced PASMC proliferation by stimulating PDE5 expression, which further degrades cGMP. Both Cyclosporine and sildenafil can suppress ET-1-stimulated PASMC proliferation in vitro.
Xi'an Jiaotong University, Xi'an, China. lu-jia1980@163.com
Jiamei
J
Lu
Xiaochuang
X
Wang
Xinming
X
Xie
Dong
D
Han
Shaojun
S
Li
Manxiang
M
Li
D000818:Animals; D019703:Calcineurin / Q000378:metabolism*; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D006152:Cyclic GMP / Q000378:metabolism; D054706:Cyclic Nucleotide Phosphodiesterases, Type 5 / Q000378:metabolism*; D016572:Cyclosporine; D004247:DNA / Q000096:biosynthesis; D019332:Endothelin-1 / Q000494:pharmacology*; D009131:Muscle, Smooth, Vascular / Q000166:cytology; D032389:Myocytes, Smooth Muscle / Q000166:cytology* / Q000201:enzymology; D050778:NFATC Transcription Factors / Q000378:metabolism*; D010879:Piperazines; D011651:Pulmonary Artery / Q000166:cytology; D011687:Purines; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction; D000068677:Sildenafil Citrate; D013450:Sulfones
D019332:Endothelin-1; D050778:NFATC Transcription Factors; D010879:Piperazines; D011687:Purines; D013450:Sulfones; D016572:Cyclosporine; D004247:DNA; D000068677:Sildenafil Citrate; D019703:Calcineurin; D054706:Cyclic Nucleotide Phosphodiesterases, Type 5; D006152:Cyclic GMP