ABSTRACT
Pulmonary hypertension (PH) is a kind of disease characterized by progressive increase of pulmonary vascular resistance and occlusive vascular remodeling. Hypoxic inductive factor-2α (HIF-2α) plays an important role in the abnormal proliferation of pulmonary vascular cells and pulmonary vascular remodeling. This review focuses on the role of HIF-2α in pulmonary hypertension at the cellular and the global level, and candidates targeting HIF-2α for the treatment of pulmonary hypertension, in order to better understand the pathogenesis of PH and find effective treatments.
ABSTRACT
Objective:To investigate the preventive effect of tetramethylpyrazine (TMP) on hypoxic pulmonary hypertension in rats and the underlying mechanism.Methods:Thirty-six male Sprague-Dawley rats were randomly divided into three groups:the normal control group,hypobaric and hypoxic group and TMP group (100 mg·kg-1·d-1).After the animal models of hypobaric and hypoxic pulmonary hypertension were established,mean pulmonary artery pressure (mPAP),mean carotid artery pressure (mCAP),ratio of right ventricular/(lift ventricular + interventricular septum) (RVHI) and morphological changes of pulmonary vessels were observed and the rates of wall thickness/external diameter (WT%) and wall area/total vascular area (WA%) were calculated.The contents of nitric oxide (NO),endothelin-1 (ET-1),hypoxic-inducible factor-1 (HIF-1) and vascular endothelial growth factor (VEGF) were detected in serum after the 21-day treatment with TMP.Results:The values of mPAP,RVHI,WT% and WA% of hypobaric and hypoxic group were significant higher than those of the normal control group (P0.05).The values of NO in serum of hypobaric and hypoxic group was lower than those of the normal control group (P<0.05) and those of TMP group were obviously higher than those of hypobaric and hypoxic group (P<0.05).The values of ET-1,HIF-1α and VEGF in serum of hypobaric and hypoxic group were higher than those of the normal control group (P<0.05) and those of TMP group were obviously lower than those of hypobaric and hypoxic group (P<0.05).Conclusion:TMP can effectively prevent pulmonary hypertension induced by hypobaric and hypoxic and structural remodeling of pulmonary arterioles.The mechanism may be related to the content up-regulation of NO and activity down-regulation of ET-1,HIF-1α and VEGF in serum of rats.
ABSTRACT
@#Brain ischemia/hypoxia preconditioning(I/HPC) is one kind of endocardial protective phenomenon by organism against blood and oxygen deficit.Researches discovered various proteins such as hypoxic inducible factor-1(HIF-1),heat shock proteins(HSPs),erythropoietin(EPO),Bcl-2 family,calcitoningene related peptide(CGRP) and so on participated in brain I/HPC.This essay explains function and participating I/HPC mechanism of these proteins.
ABSTRACT
@#Brain ischemia/hypoxia preconditioning(I/HPC) is one kind of endocardial protective phenomenon by organism against blood and oxygen deficit.Researches discovered various proteins such as hypoxic inducible factor-1(HIF-1),heat shock proteins(HSPs),erythropoietin(EPO),Bcl-2 family,calcitoningene related peptide(CGRP) and so on participated in brain I/HPC.This essay explains function and participating I/HPC mechanism of these proteins.
ABSTRACT
Small hairpin RNA (shRNA) was used to silence the HIF1α gene in human retinal pigment epithelial cells (RPE) under hypoxia in order to observe the effect of gene silencing on the expression of matrix metalloproteinase tissue inhibitor 1 (TIMP1). By using chemical hypoxic inducer CoCl2 to mimic RPE hypoxic environment, shRNA against the targeting region of HIF1α mRNA sequence was synthesized by a method of in vitro transcription, and the HIF1α was interfered in RPE cultured under hypoxia (induced by 150 μmol/L CoCl2 ). RT-PCR was employed to detect the expression of HIF1α and TIMP1. The expression levels of HIF1α and TIMP1 were measured by using Western blotting. The results showed that after the RPE were transfected with specific shRNA against HIF1α mRNA, RT-PCR revealed that under hypoxia, the efficacy of HIF1α gene silencing in RPE was 83. 4 %. Western blotting revealed that the expression levels of HIF1α protein was dramatically dropped. In addition, RT-PCR results demonstrated that the expression of TIMP1 mRNA was decreased by 28.9 %, and the expression levels of TIMP1 protein were also significantly reduced by Western blotting. It was suggested that shRNA targeted against HIF1α mRNA could effectively silence the HIF1α gene, subsequently effectively inhibit the hypoxia-induced up-regulation of TIMP1.