cyclin-d1 and Familial-Primary-Pulmonary-Hypertension

Pulmonary arterial hypertension, characterized by pulmonary vascular remodelling and vasoconstriction, is associated with excessive proliferative changes in pulmonary vascular walls. However, the role of HDACs in the phenotypic alteration of pulmonary arterial smooth muscle cells (PASMC) is largely unknown.. Pulmonary arterial smooth muscle cells were isolated from newborn sheep. Cell cycle analysis was performed by flow cytometry. mRNA and protein expression were measured by real-time PCR and Western blot analysis. Wound-healing scratch assay was used to measure cell migration. Contractility of newborn PASMCs was determined by gel contraction assay. Chromatin immunoprecipitation was used to examine histone modifications along the p21 promoter region. Global DNA methylation was measured by liquid chromatography-mass spectroscopy.. Inhibition of class I and class II HDACs by apicidin and HDACi VIII suppressed proliferation of newborn PASMC and induced cell cycle arrest in G1 phase. Acetyl H3 levels were higher in newborn PASMC treated with apicidin and HDACi VIII. This was accompanied by increased expression of p21 and reduced expression of CCND1 but not p53. HDAC inhibition altered histone codes around the p21 promoter region in NPASMC. Apicidin inhibited serum-induced cell migration, and modulated profiling of expression of genes encoding pro-oxidant and antioxidant enzymes. Contractility and global DNA methylation levels of newborn PASMCs were also markedly modulated by apicidin.. Our results demonstrate that class I HDACs are clearly involved in phenotypic alteration of newborn PASMC.

Topics: Acetylation; Animals; Antioxidants; Cell Cycle Checkpoints; Cell Movement; Cell Proliferation; Cyclin D1; Cyclin-Dependent Kinase Inhibitor p21; DNA Methylation; Familial Primary Pulmonary Hypertension; G1 Phase; Histone Deacetylase Inhibitors; Histone Deacetylases; Histones; Humans; Hypertension, Pulmonary; Infant, Newborn; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Phenotype; Promoter Regions, Genetic; Pulmonary Artery; Sheep; Transcriptome; Tumor Suppressor Protein p53

Pulmonary arterial hypertension (PAH) is a devastating disease, and no effective treatments are available. Hypoxia-induced pulmonary artery remodeling, including smooth muscle cell proliferation, contributes to PAH, but the exact mechanisms underlying this abnormal process are largely undefined. The forkhead box M1 (FoxM1) transcription factor regulates cancer cell growth by modulating gene expression critical for cell cycle progression. Here, we report for the first time, to the best of our knowledge, a novel function of FoxM1 in the hypoxia-stimulated proliferation of human pulmonary artery smooth muscle cells (HPASMCs). Exposure to hypoxia caused a marked up-regulation of FoxM1 gene expression, mainly at the transcription level, and this induction correlated with HPASMC cell proliferation. The knockdown of FoxM1 inhibited the hypoxia-stimulated proliferation of HPASMCs. We found that the knockdown of HIF-2α, but not HIF-1α, diminished FoxM1 induction in response to hypoxia. However, the knockdown of FoxM1 did not alter expression levels of HIF-2α or HIF-1α, suggesting that HIF-2α is an upstream regulator of FoxM1. Furthermore, the knockdown of FoxM1 prevented the hypoxia-induced expression of aurora A kinase and cyclin D1. Collectively, our results suggest that hypoxia induces FoxM1 gene expression in an HIF-2α-dependent pathway, thereby promoting HPASMC proliferation.

Topics: Aurora Kinases; Basic Helix-Loop-Helix Transcription Factors; Cell Hypoxia; Cell Proliferation; Cells, Cultured; Cyclin B; Cyclin D1; Familial Primary Pulmonary Hypertension; Forkhead Box Protein M1; Forkhead Transcription Factors; Gene Expression; Humans; Hypertension, Pulmonary; Hypoxia; Hypoxia-Inducible Factor 1, alpha Subunit; Myocytes, Smooth Muscle; Protein Serine-Threonine Kinases; Pulmonary Artery