Peng Qu

P2X7R is involved in the progression of atherosclerosis by promoting NLRP3 inflammasome activation.

Purinergic 2X7 receptor (P2X7R) and nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) are expressed in macrophages in atherosclerotic lesions. However, the mechanisms through which P2X7R participates in the inflammatory response in atherosclerosis remain largely unknown. The aim of the present study was to investigate the role of P2X7R in atherosclerosis and the mechanisms of action of the NLRP3 inflammasome following stimulation with oxidized low-density lipoprotein (oxLDL). We observed the expression and distribution of P2X7R in the atherosclerotic plaque in the coronary arteries from an autopsy specimen and in that of the aortic sinuses of apoE−/− mice by immunohistochemistry and immunofluorescence staining. The specificity of short interfering RNA (siRNA) was used to suppress P2X7R and NLRP3 mRNA expression. RT-qPCR and western blot analysis were used to analyze mRNA and protein expression, respectively. Co-immunoprecipitation was used to examine the interaction between protein kinase R (PKR) phosphorylation and NLRP3. P2X7R and NLRP3 were expressed at high levels in the atherosclerotic plaque in the coronary arteries. Stimulation with oxLDL upregulated P2X7R, NLRP3 and interleukin (IL)-1β expression. P2X7R knockdown by siRNA suppressed NLRP3 inflammasome activation by inhibiting the PKR phosphorylation mediated by oxLDL. In the atherosclerotic lesions in the aortic sinuses of apoE−/− mice, P2X7R expression was found at high levels. Moreover, P2X7R siRNA attenuated the development of atherosclerosis in the apoE−/− mice. In conclusion, our results demonstrate that P2X7R plays a significant role in the development of atherosclerosis and regulates NLRP3 inflammasome activation by promoting PKR phosphorylation.

NLRP3 inflammasome in peripheral blood monocytes of acute coronary syndrome patients and its relationship with statins.

ObjectivesDespite recent advances in the understanding of the role of NLRP3 inflammasomes in coronary atherosclerosis, further work on their activation and clinical implications remains to be performed. In this study, we aimed to evaluate the effect of the dose of rosuvastatin on NLRP3 and cathepsin-B expression in peripheral blood monocytes in patients with acute coronary syndrome. MethodsA total of 123 participants were enrolled in this study; these included acute myocardial infarction (AMI) patients (n=53), unstable angina patients (UA, n=40), and normal controls (n=30). AMI and UA patients were divided into high-dose rosuvastatin (20 mg) and low-dose rosuvastatin (5 mg) groups. NLRP3, cathepsin-B, and downstream cytokine expressions were appropriately evaluated using real-time PCR, flow cytometry, western blotting and enzyme-linked immunosorbent assay. The concentrations of serum inflammatory markers were also evaluated for correlation with NLRP3 levels. ResultsAMI and UA patients had higher NLRP3, cathepsin-B, interleukin-18 (IL-18), pro-IL-18, IL-1&bgr;, and pro-IL-1&bgr; expressions as compared with the control group (P<0.05). This corresponded with higher levels of serum total cholesterol, serum low-density lipoprotein cholesterol, and oxidized low-density lipoprotein in UA and AMI patients (P<0.05). Rosuvastatin at a concentration of 20 mg led to a significant decrease (P<0.05) in the expressions of NLRP3, cathepsin-B, and their downstream cytokines as compared with 5 mg rosuvastatin (P>0.05) from baseline to 4 weeks. This study also showed a positive correlation between NLRP3, cathepsin-B, and downstream inflammatory mediators. ConclusionNLRP3 is involved in inflammation that leads to atherosclerosis. A high dose of rosuvastatin can modulate the inflammatory process of atherosclerosis by downregulating the expression of NLRP3, cathepsin-B, and their downstream mediators. These findings provide insight into the pathogenesis and management of acute coronary syndrome, with NLRP3 as the potential target.

Saikosaponin-a Attenuates Oxidized LDL Uptake and Prompts Cholesterol Efflux in THP-1 Cells.

Abstract: Saikosaponins-a (Ssa) is a major bioactive extract of Radix Bupleuri which is a traditional Chinese medicine. The roles of inflammatory response and lipid transportation in the process of atherosclerosis have drawn increasing attention. We explored the regulation of lipid transportation and immune-inflammatory role of Ssa in early atherosclerosis. The antiatherogenic actions and possible molecular mechanisms of Ssa were texted in THP-1 cells. We examined the effect of Ssa on oxidized low-density lipoprotein (ox-LDL)-induced lipid uptake, cholesterol efflux, immune-inflammatory response. THP-1 macrophages were treated with Ssa followed by ox-LDL for 24 hours. Results from western blot showed that Ssa obviously reduced lipoprotein uptake to block foam cell formation and the expression of Density Lipoprotein Receptor-1 and CD36. Ssa also significantly boosted cholesterol efflux and the expression of ATP binding cassettetransporter A1 and peroxisome proliferator-activated receptor &ggr;. The results also indicated that Ssa inhibited ox-LDL–induced activation of AKT and nuclear factor-&kgr;B, assembly of NLRP3 inflammasome and production of proinflammatory cytokines. It is suggested that the ability against immune inflammatory response of Ssa is due to modulation of the PI3K/AKT/NF-&kgr;B/NLRP3 pathway. In conclusion, this study provides new insight into Ssas molecular mechanism and its therapeutic potential in the treatment of atherosclerosis.

NF-κB inhibitor on Toll-like receptor 4 signal-induced expression of angiotensinogen and AT1a receptor in neonatal rat left ventricular myocytes

Effects of toll-like receptor 4 (TLR4)/nuclear factor-κB (NF-κB) pathway on expression of angiotensinogen and AT1a receptor were investigated, to explore the role of TLR4/NF-κB signaling pathway in cardiovascular disease. Neonatal rat left ventricular myocytes (NRVMs) were cultured and cardiomyocytes were identified by immunocytochemical staining of sarcomeric α-actin. NRVMs were treated with lipopolysaccharide (LPS) at a dose of 10, 100 and 1,000 ng/ml, and RT-PCR was performed 24 h later to detect the expression of TLR4, angiotensinogen (ATG) and AT1a at mRNA level. NRVMs were cultured and pretreated with caffeic acid phenethylester (CAPE) for 30 min. Then NRVMs were stimulated with LPS (1,000 ng/ml) for 24 h. Nuclear translocation of NF-κB p65 was detected by immunocytochemistry. Expression of TLR4, angiotensinogen and AT1a receptor after CAPE stimulation was detected by RT-PCR. TLR4 mRNA was highly expressed in in vitro cultured NRVMs, and the expression level was significantly increased by LPS (10–1,000 ng/ml) stimulation in a dose-dependent manner (P<0.05). LPS stimulation also significantly increased the expression levels of angiotensinogen and AT1a receptor in a dose-dependent manner (P<0.05). NF-κB was activated and nuclear translocation of NF-κB p65 occurred after stimulation with LPS (1,000 ng/ml) for 24 h, while CAPE (20 µg/ml) inhibited the nuclear translocation of NF-κB p65 and inhibited LPS-induced expression of angiotensinogen and AT1a receptor. With LPS stimulation, TLR4 signaling positively regulates the expression of TLR4 and upregulates the expression of angiotensinogen and AT1a receptor in NRVMs. CAPE, an inhibitor of NF-κB, inhibited NF-κB p65 activation and inhibited the upregulation of TLR4, angiotensinogen and AT1a receptors induced by LPS. These results suggest that NF-κB plays a key regulatory role in the above-mentioned effects induced by LPS. Intervention with TLR4/NF-κB signaling may become a new target for prevention and treatment of cardiovascular diseases.

PS 02-12 Analysis of serum stromal interaction molecules 1 (STIM1) in hypertension combining acute coronary syndrome

Objective: The aim of this study is to explore the change of serum stromal interaction molecules 1 (STIM1) in the people with hypertension combining acute coronary syndrome. Design and Method: The study group was composed of 30 patients with primary hypertension combining acute coronary syndrome (ACS, A group) and 30 patients with primary hypertension (B group). The control group (C group) was composed of 30 healthy individuals. The severity of coronary artery disease was determined by the Gensini score. STIM1 concentration was measured via Elisa. SPSS19.0 was used for statistical analysis. Results: The expression level of STIM1 in patients with primary hypertension(607.69 ± 108.89 and 410.26 ± 71.86), inclouding A group and B group, was significantly higher than that in control (339.53 ± 66.39)(P < 0.05). Pearson correlation analysis showed that the expression level of STIM1 was positively correlated with Gensini Score(R = 0.836, P < 0.05). While the level of STIM1 was negatively correlated with left ventricular ejection fraction(R = −0.333, P < 0.05) and NO(R = −0.768, P < 0.05). Univariate Logistic regression analysis showed that sex (OR = 0.010), smoking (OR = 3.656), WBC (OR = 1.236), ApoA1 (OR = 0.014), Scr (OR = 1.033), ALT (OR = 1.043), NO (OR = 0.965) and STIM1 (OR = 1.023) were risk factors for ACS(P < 0.05). In addition, multivariable Logistic regression analysis showed that smoking (OR = 6.656) and STIM1 (OR = 1.026) were associated with ACS (P < 0.05). Conclusions: The expression level of STIM1 in patients with primary hypertension was higher than that in control. The expression level of STIM1 in patient with hypertension combining acute coronary syndrome (A group) was higher than in hypertension(B group). And the expression level of STIM1 was positively correlated with Gensini Score, which indicated that the expression level of STIM1 might reflect the severity of coronary artery lesions. The expression level of STIM1 was negatively correlated with NO. Which indicated that the expression level of STIM1 might reflect the endothelial function.