rBMSCs/ITGA5B1 Promotes Human Vascular Smooth Muscle Cell Differentiation via Enhancing Nitric Oxide Production

BACKGROUND AND OBJECTIVES: Previous studies have shown that integrins alpha5beta1 (ITGA5B1) gene-modified rat bone marrow mesenchymal stem cells (rBMSCs) could prevent cell anoikis and increase the nitric oxide (NO) production. Here we examined the capability of rBMSCs/ITGA5B1 on the phenotype modulation of Human Pulmonary Artery Smooth Muscle Cell (HPASMC) in vitro. METHODS AND RESULTS: The synthetic (dedifferentiated) phenotype of HPASMC was induced by monocrotaline (MCT, 1μM) for 24 h and then co-cultured with rBMSCs/ITGA5B1 in a transwell culture system. The activation of NO/cGMP (nitric oxide/Guanosine-3′, 5′-cyclic monophosphate) signaling was investigated in HPASMC. The changes of pro-inflammatory factors, oxidative stress, vasodilator, vasoconstrictor, contractile and synthetic genes, and the morphological changes of HPASMC were investigated. The results of this study showed that the NO/cGMP signal, endothelial nitric oxide synthase (eNOS) expression, the expression of the vasoprotective genes heme oxygenase-1 (HMOX1) and prostaglandin-endoperoxide synthase 2 (PTGS2) were increased, but the expression of transforming growth factor-β1 (TGF-β1), CCAAT/enhancer-binding proteins delta (Cebpd), Krüppel-like factor 4 (KLF4), and activating transcription factor 4 (ATF4) were reduced in MCT treated HPASMC co-cultured with rBMSCs/ITGA5B1. The synthetic smooth muscle cells (SMCs) phenotype markers thrombospondin-1, epiregulin and the vasoconstrictor endothelin (ET)-1, thromboxane A2 receptor (TbxA2R) were down-regulated, whereas the contractile SMCs phenotype marker transgelin expression was up-regulated by rBMSCs/ITGA5B1. Furthermore, rBMSCs/ITGA5B1 promoted the morphological restoration from synthetic (dedifferentiation) to contractile (differentiation) phenotype in MCT treated HPASMC. CONCLUSIONS: rBMSCs/ITGA5B1 could inhibit inflammation and oxidative stress related genes to promote the HPASMC cell differentiation by activation NO/cGMP signal.

Effect of Mycophenolic Acid on Human Vascular Smooth Muscle Cell Proliferation and Its Signal Transduction

PURPOSE: Vascular smooth muscle cells (VSMCs) migration and proliferation play important roles in chronic allograft rejection. Mycophenolic acid (MPA) inhibits the proliferation of VSMCs, glomerular mesangial cells and fibroblasts as well as lymphocytes. Since reactive oxygen species (ROS) and mitogen-activated protein kinase (MAPK) play important roles in the proliferation of VSMCs, the present study examined the effects of MPA on intracellular ROS generation, activation of ERK and p38 MAPK, and the proliferation of VSMCs cultured under platelet derived growth factor (PDGF). METHODS: Human VSMCs obtained from ATCC were cultured with RPMI-1640 containing 10% fetal bovine serum. Near confluent VSMCs were incubated with serum-free media for 48 hours to arrest and synchronize the cell growth. MPA was administered 1 hour before the addition of PDGF. 5-(and-6)- chloromethyl-2',7'-dichlorodihydrofluorescein (DCF)-sensitive intracellular ROS was detected by FACS. Activations of ERK1/ERK2 and p38 MAPK were measured by Western blot analysis. Proliferation of VSMC was assessed by [(3)]. RESULTS: PDGF administered at 10 ng/ml, which induced human VSMCs proliferation, rapidly increased intracellular ROS by 1.6-fold (P<0.05), ERK1/ERK2 activation by 2.1-fold, (P<0.05) and p38 MAPK activation by 1.9-fold (P<0.05), respectively, as compared to the control. MPA 1 and 10nM effectively inhibited PDGF-induced human VSMCs proliferation. MPA also effectively inhibited PDGF-induced intracellular ROS generation as well as ERK1/ERK2 and p38 MAPK activation. CONCLUSION: The present study suggests that MPA inhibits PDGF-induced human VSMCs proliferation, possibly by inhibiting intracellular ROS generation and the phosphorylation of ERK1/ERK2 and p38 MAPK. H]-thymidine incorporation.