Calcineurin ‐NFAT Signaling Molecules Regulate Proliferation, Migration and Apoptosis in PASMCs of Pulmonary Hypertensive Rats induced by Monocrotaline

Abstract

Pulmonary arterial hypertension (PAH) is characterized by increased resting intracellular free Ca2+ concentration of pulmonary arterial smooth muscle cells (PASMCs), angiogenesis and vascular remodeling. Previous studies of PAH show that canonical transient receptor potential (TRPC) genes are upregulated and store‐operated Ca2+ entry is augmented in PASMCs of monocrotaline (MCT)‐treated rats. While increased intracellular Ca2+ can further activate calcineurin (CaN) and make nuclear factor of activated T cells (NFAT) dephosphorylation and nuclear translocation. Since CaN and NFAT may functionally regulate the transcription of a variety of cytokines, we sought to examine the effects of CaN‐NFAT signaling molecules on proliferation, apoptosis and migration in PASMCs of control and MCT‐induced rats. Rats developed severe PAH and right ventricular hypertrophy within three weeks after single intraperitoneal injection of MCT at a dose of 60 mg/kg. MCT treatment can upregulated mRNA and protein expression of STIM1/2‐ORAI1/2‐CaNBβ‐NFATc2/3/4 on PAs, as well as developed proliferation and migration and decreased apoptosis on PASMCs. Pretreatment with Cyclosporine A (CsA) inhibited proliferation and migration on PASMCs of control (CON) and MCT rats, in a dose dependence manner (15, 30 60μM), but inhibited apoptosis only on high concentration (60μM). Proliferation, migration and apoptosis resistance of PASMCs in CON and MCT rats were obviously inhibit by siRNA of NFATc2 and NFATc4. Pretreatment with siRNA of NFATc3 were no effect to proliferation, migration and apoptosis resistance of PASMCs in CON rats, but can obviously suppressed proliferation and migration, promoted apoptosis of PASMCs in MCT rats. Our results hence show that MCT treatment caused significant alterations in the expression of STIM1/2‐ORAI1/2‐CaNβ‐NFATc2/3/4 signaling molecules. NFATc2/4 are essential factor for PASMCs growth, however, NFATc2/34 may contribute to pulmonary vascular remodeling in PAH induced by MCT.Support or Funding InformationThis work is supported by NSFC31171104, NSFC 31371165, NSFC 31571179 and FJMU09ZD010