Expression of NADPH Oxidase and Production of Reactive Oxygen Species in Aorta in an Active Immunization Mouse Model with AT1-EC2 Peptide

The antibody against AT1-EC2 plays a role in some kinds of inflammatory vascular diseases including malignant hypertension,preeclampsia,and renal-allograft rejection,but the detailed mechanisms remain unclear.In order to investigate the changes of NADPH oxidase and reactive oxygen species in the aorta in a mouse model which can produce AT1-EC2 antibody by active immunization with AT1-EC2 peptide,15 mice were divided into three groups:control group,AT1-EC2-immunized group,and AT1-EC2-immunized and valsartan-treated group.In AT1-EC2-immunized group and AT1-EC2-immunized and valsartan-treated group,the mice were immunized by 50 μg peptide subcutaneously at multiple points for 4 times:0,5,10,and 15 days after the experiment.In AT1-EC2-immunized and valsartan-treated group,valsartan was given at a dose of 100 mg/kg every day for 20 days.After the experiment,the mice were sacrificed under anesthesia and the aortas were obtained and frozen in liquid nitrogen for the preparation of frozen section slides and other experiments.The titer of AT1-EC2 was assayed by using ELISA.The level of NOX1 mRNA in the aorta was determined by using RT-PCR.The expression of NOX1 was detected by using Western blotting.Confocal scanning microscopy was used to assay the α-actin and NOX1 expression in the aortic tissue.The O 2.production was detected in situ after DHE staining.The mice produced high level antibody against AT1-EC2 in AT1-EC2-immunized group and AT1-EC2-immunized and valsartan-treated group,and the level of NOX1 mRNA in the aortic tissues was 1.6±0.4 times higher and the NOX1 protein expression was higher in AT1-EC2-immunized group than in control group.There were no significant differences in the level of NOX1 mRNA and protein expression between control group and AT1-EC2-immunized and valsartan-treated group.The expression and co-localization of α-actin and NOX1 in AT1-EC2-immunized group increased significantly as compared with those in control group,and the O 2.production increased about 2.7 times as compared with control group.There were no significant differences between control group and AT1-EC2-immunized and valsartan-treated group.It is concluded that active immunization with AT1-EC2 can activate NOX1-ROS,and increase vascular inflammation,which can be inhibited by AT1 receptor blocker valsartan.This may partially explain the mechanism of the pathogenesis of inflammatory vascular diseases related to antibody against AT1-EC2.

Paeonol reduces microbial metabolite α-hydroxyisobutyric acid to alleviate the ROS/TXNIP/NLRP3 pathway-mediated endothelial inflammation in atherosclerosis mice

Gut microbiota dysbiosis is an avenue for the promotion of atherosclerosis(AS)and this effect is mediated partly via the circulating microbial metabolites.More microbial metabolites related to AS vascular inflammation,and the mechanisms involved need to be clarified urgently.Paeonol(Pae)is an active compound isolated from Paeonia suffruticoas Andr.with anti-As inflammation effect.However,considering the low oral bioavailability of Pae,it is worth exploring the mechanism by which Pae reduces the harmful metabolites of the gut microbiota to alleviate AS.In this study,ApoE--mice were fed a high-fat diet(HFD)to establish an AS model.AS mice were administrated with Pae(200 or 400 mg:kg')by oral gavage and fecal microbiota transplantation(FMT)was conducted.16S rDNA sequencing was performed to investigate the composition of the gut microbiota,while metabolomics analysis was used to identify the metabolites in serum and cecal contents.The results indicated that Pae significantly improved AS by regulating gut microbiota composition and microbiota metabolic profile in AS mice.We also identified a-hydroxyisobutyric acid(HIBA)as a harmful microbial metabolite reduced by Pae.HIBA supplementation in drinking water promoted AS inflammation in AS mice.Furthermore,vascular endothelial cells(VECs)were cultured and stimulated by HIBA.We verified that HIBA stimulation increased intracellular ROS levels,thereby inducing VEC inflammation via the TXNIP/NLRP3 pathway.In sum,Pae reduces the production of the microbial metabolite HIBA,thus alleviating the ROS/TXNIP/NLRP3 pathway-mediated endothelial inflammation in AS.Our study innovatively confirms the mechanism by which Pae reduces the harmful metabolites of gut microbiota to alleviate AS and proposes HIBA as a potential biomarker for AS clinical judgment.

Post-transcriptional gene regulation by RNA-binding proteins in vascular endothelial dysfunction

Endothelial cell dysfunction is a term which implies the dysregulation of normal endothelial cell functions,including impairment of the barrier functions,control of vascular tone,disturbance of proliferative and migratory capacity of endothelial cells,as well as control of leukocyte trafficking.Endothelial dysfunction is an early step in vascular inflammatory diseases such as atherosclerosis,diabetic vascular complications,sepsis-induced or severe virus infection-induced organ injuries.The expressions of inflammatory cytokines and vascular adhesion molecules induced by various stimuli,such as modified lipids,smoking,advanced glycation end products and bacteria toxin,significantly contribute to the development of endothelial dysfunction.The transcriptional regulation of inflammatory cytokines and vascular adhesion molecules has been well-studied.However,the regulation of those gene expressions at post-transcriptional level is emerging.RNA-binding proteins have emerged as critical regulators of gene expression acting predominantly at the post-transcriptional level in microRNA-dependent or independent manners.This review summarizes the latest insights into the roles of RNA-binding proteins in controlling vascular endothelial cell functions and their contribution to the pathogenesis of vascular inflammatory diseases.

Sterol carrier protein 2: A promising target in the pathogenesis of atherosclerosis

Atherosclerosis, the underlying pathophysiological basis of cardiovascular disease, has been recognized as a lipid-driven chronic inflammatory disease. Sterol carrier protein 2 (SCP-2) is a 13-kDa non-specific lipid-transfer protein expressed by various tissues and cells, such as liver, heart, vascular smooth muscle cells (VSMCs), and macrophages. SCP-2 has an extensive role in cardiovascular and metabolic diseases. Recently, SCP-2 was reported to promote the development of atherosclerosis by regulating lipid metabolism and peroxidation, endocannabinoid metabolism, vascular inflammation, and fatty acid metabolism. In this review, we summarized the recent advances regarding the role of SCP-2 in the pathogenesis of atherosclerosis and tried to provide a rationale for future investigation and a better understanding of the biological functions of SCP-2 in atherosclerotic cardiovascular disease.

Baicalein protects against the development of angiotensin II-induced abdominal aortic aneurysms by blocking JNK and p38 MAPK signaling

An abdominal aortic aneurysm(AAA) is a permanent, localized dilatation of the abdominal aorta. In western countries, the morbidity of AAA is approximately 8%. Currently, pharmacotherapies for AAA are limited. Here, we demonstrate that baicalein(BAI), the main component of the Chinese traditional drug "Huang Qin", attenuates the incidence and severity of AAA in Apoe儃/儃 mice infused with angiotensin II(AngII). Mechanically, BAI treatment decreases AngII-induced reactive oxygen species(ROS) production in the aortic wall. Moreover, BAI inhibits inflammatory cell accumulation in the aortas of mice infused with AngII. It also inhibits AngII-induced activation of matrix metalloproteinase 2(MMP-2) and MMP-9 to maintain elastin content in vivo. In addition, it blocks AngII cascade by downregulating angiotensin type 1 receptor(AT1R) and inhibiting mitogen-activated protein kinases(MAPKs). Taken together, our findings show that BAI is an effective agent for AAA prevention.