Overexpression of heme oxygenase-1 protects smooth muscle cells against oxidative injury and inhibits cell proliferation

To investigate whether the expression of exogenous heme oxygenase-1 (HO-1) gene within vascular smooth muscle cells (VSMC) could protect the cells from free radical attack and inhibit cell proliferation, we established an in vitro transfection of human HO-1 gene into rat VSMC mediated by a retroviral vector. The results showed that the profound expression of HO-1 protein as well as HO activity was 1.8- and 2.0-fold increased respectively in the transfected cells compared to the non-transfected ones. The treatment of VSMC with different concentrations of H2O2 led to the remarkable cell damage as indicated by survival rate and LDH leakage. However, the resistance of the HO-1 transfected VSMC against H2O2 was significantly raised. This protective effect was dramatically diminished when the transfected VSMC were pretreated with ZnPP-IX, a specific inhibitor of HO, for 24 h. In addition, we found that the growth potential of the transfected cells was significantly inhibited directly by increased activity of HO-1, and this effect might be related to decreased phosphorylation of MAPK. These results suggest that the overexpression of introduced hHO-1 is potentially able to reduce the risk factors of atherosclerosis, partially due to its cellular protection against oxidative injury and to its inhibitory effect on cellular proliferation.

Advanced oxidation protein products induce monocyte chemoattractant protein-1 expression via p38 mitogen-activated protein kinase activation in rat vascular smooth muscle cells

Background Advanced oxidation protein products （AOPPs） are new uremic toxins reported by Witko-Sarsat in 1996, which are associated with the pathogenesis of atherosclerosis. However, the mechanisms by which AOPPs enhance atherosclerosis have not been fully understood. Monocyte chemoattractant protein-1 （MCP-1） is a chemokine which stimulates migration of monocytes and plays a critical role in the development of atherosclerosis. In this study, we investigated the effect of AOPPs on MCP-1 expression in cultured vascular smooth muscle cells （VSMCs）.

Qibai Pingfei capsule medicated serum inhibits the proliferation of hypoxia-induced pulmonary arterial smooth muscle cells via the Ca^(2+)/calcineurin/nuclear factor of activated T-cells 3 pathway

OBJECTIVE: To observe the effect of Qibai Pingfei capsule(QBPF) medicated serum on the proliferation of rat pulmonary arterial smooth muscle cells(PASMCs) under hypoxia conditions and to investigate its key molecular effects on the Ca^(2+)/calcineurin/nuclear factor of activated T-cells 3(NFATc3) signaling pathway.METHODS: QBPF was provided to rats via continuous gavage for 10 days. Primary rat PASMCs were cultured using the direct adherent culture method.Methyl thiazolyl tetrazolium assay was used to eval-uate the effect of QBPF on PASMCs proliferation under hypoxia conditions. Laser scanning confocal microscopy was used to detect changes in intracellular free calcium([Ca^(2+)]_i) in PASMC-loaded Fluo-3-AM.Real-time quantitative polymerase chain reaction and western blot were used to detect the transcription and protein expression levels of calcineurin and NFATc3 genes in PASMCs.RESULTS: Compared with normoxia conditions,PASMCs proliferated at 12, 24, 48, and 72 h under hypoxia conditions. QBPF at concentrations of 5%,10%, and 20% could inhibit hypoxia-induced PASMC proliferation to different degrees. The inhibitory effect was most significant in the 20% QBPF group under 24 h hypoxia conditions. The concentration of [Ca^(2+)]_iin PASMCs under hypoxia was increased and [Ca^(2+)]_iwas significantly decreased when co-incubated with QBPF at 5%, 10%, and 20%. Compared with normoxia conditions, the m RNA and protein expression levels of calcineurin and NFATc3 in PASMCs induced by hypoxia were up-regulated.QBPF application significantly down-regulated m RNA and protein expression levels of calcineurin and NFATc3 in PASMCs.CONCLUSION: QBPF can effectively inhibit hypoxia-induced proliferation of PASMCs through down-regulation of key molecular expression via the Ca^(2+)/calcineurin/NFATc3 pathway.

Mechanisms responsible for pulmonary hypertension

Pulmonary hypertension is a pathophysiologic process characterized by progressive elevation of pulmonary vascular resistance and right heart failure, which is a common complication of many diseases. Pulmonary hypertension with no apparent causes （unknown etiology） is termed primary pulmonary hypertension or, more recently, idiopathic pulmonary arterial hypertension （IPAH）. Before the availability of disease-specific （targeted） therapy （through the mid-1980s） the median life expectancy from the time of diagnosis in patients with this disease was 2.8 years. Modem treatment has markedly improved physical function and has extended survival, and the 5-year mortality is 50%. Although there is already more than 100 years of research history, the mechanisms of this disease are still not very clear. Recently, with the development of cell biology and molecular genetics, further research into the mechanisms responsible for pulmonary hypertension have been possible, which has helped in its diagnosis and treatment. It is believed that the mechanisms of pulmonary hypertension can not only be described by pathophysiology but involve multiple factors （pathways） like cellular, humoral and molecular genetics, etc.