GAS5 knockdown suppresses inflammation and oxidative stress induced by oxidized low-density lipoprotein in macrophages by sponging miR-135a.

A large number of long non-coding RNAs have been confirmed to play vital roles in regulating various biological processes. Abnormal expression of growth arrest-specific transcript 5 (GAS5) is reported to be involved in the development of atherosclerosis (AS). This work is to explore the detailed mechanism underling how GAS5 regulates AS progression. We found that the abundance of GAS5 was markedly increased, and miR-135a was decreased in AS patient serums and ox-LDL-induced human THP-1 cells dose and time dependently. Interference of GAS5 suppressed inflammation and oxidative stress induced by ox-LDL in THP-1 cells. Mechanistically, GAS5 acted as a molecular sponge of microRNA-135a (miR-135a). Rescue assays indicated that knockdown of miR-135a partially rescued small interference RNA for GAS5-inhibited inflammatory cytokines release and oxidative stress in ox-LDL-triggered THP-1 cells. In conclusion, the absence of GAS5-inhibited inflammatory response and oxidative stress induced by ox-LDL in THP-1 cells via sponging miR-135a, providing a deep insight into the molecular target for AS treatment.

Clinical significance of leukotriene b4 and extracellular matrix metalloproteinase inducer in acute coronary syndrome.

PURPOSE: Leukotriene B4 (LTB4) and extracellular matrix metalloproteinase (EMMPRIN) have been suggested as modulators of atherosclerotic plaque instability. This study sought to evaluate the potential diagnostic implication of LTB4 and EMMPRIN in patients with acute coronary syndrome (ACS). METHODS: Patients (n=153) who underwent coronary angiography, including 105 patients diagnosed with ACS, were divided into four groups: stable angina pectoris (SAP, n=19), unstable angina pectoris (UAP, n=39), acute myocardial infarction (AMI, n=66) and control (with normal coronary angiography, n=29). EMMPRIN expression in peripheral blood mononuclear cells was determined by flow cytometry and serum LTB4 levels were measured by ELISA. To examine whether LTB4 can regulate the expression of EMMPRIN and matrix metalloproteinases (MMPs) in macrophages, differentiated THP-1 macrophages were stimulated with different concentrations of LTB4 (10-10-10-7mmol/L). Expression of EMMPRIN was evaluated by Western blotting. MMP-9 mRNA expression and enzymatic activity were determined by RT-PCR and SDS-PAGE gelatin zymography. RESULT: Serum LTB4 concentration was significantly higher in AMI and UAP groups, compared with control and SAP groups (p < 0.01). Subgroups analysis showed that LTB4 was significantly higher in the AMI < 24h group, compared with the AMI > 24h group. Expression of EMMPRIN on circulating monocytes was significantly higher in patients with UAP and AMI (> 24h), compared with control, SAP and AMI (< 24h) groups (p < 0.05). In vitro study showed LTB4 up-regulated the expression of EMMPRIN, as well as the expression and activity of MMP-9, in cultured THP-1-derived macrophages (p < 0.05). CONCLUSION: LTB4 and EMMPRIN are associated with the pathogenesis of ACS and may be potential biomarkers for patients with ACS.

[Expression of extracellular matrix metalloproteinase inducer in the unstable plaque of patients with acute coronary syndrome].

OBJECTIVE: To observe the expression of extracellular matrix metalloproteinase inducer (EMMPRIN) in the unstable plaque of patients with acute coronary syndrome (ACS), and the impact of leukotriene B4 (LTB4) on the EMMPRIN expression in macrophages. METHODS: The EMMPRIN expression was detected by immunohistochemistry in 11 unstable plaques from patients with ACS. Protein expression of EMMPRIN was evaluated by Western blot on macrophages differentiated from THP-1 which were stimulated with LTB4 in the absence or presence of LTB4 antagonist U75302. There are 8 study groups: 1-THP-1, 2-8-the macrophages derived from THP-1, 2-6-macrophages were stimulated by LTB4 (0, 10(-10), 10(-9), 10(-8) and 10(-7) mol/L) for 24 h, 7-8-the macrophages were pretreated by 10(-6) mol/L or 10(-7) mol/L U75302 2 h before the LTB4 (10(-7) mol/L) stimulation. RESULTS: Abundant EMMPRIN expression was detected in macrophages and smooth muscle cells of unstable plaques from ACS patients. As to the THP-1 derived macrophages, EMMPRIN expression was significantly upregulated in a concentration-dependent manner in LTB4 stimulated groups, which was significantly higher in group 3-6 than in the THP-1 group (group 1) and macrophages group (group 2) (all P < 0.05) and pretreatment with U75302 significantly reduced the LTB4 induced upregulation of EMMPRIN in a dose-dependent manner (P < 0.05). CONCLUSION: EMMPRIN expression is enhanced in macrophages and smooth muscle cells on unstable coronary artery plaques from ACS patients. LTB4 could stimulate EMMPRIN expression on THP-1 derived macrophages suggesting that LTB4 and EMMPRIN might be both involved in the formation and progression of unstable plaques, future studies are warranted to explore if LTB4 and EMMPRIN antagonists are effective or not for treating patients with ACS.

Matrix metalloproteinase-1, -3, and -9 gene polymorphisms and the risk of idiopathic dilated cardiomyopathy in a Chinese Han population.

OBJECTIVES: To investigate the association between matrix metalloproteinase (MMP)-1(-1607 1G/2G), MMP-3(-1171 5A/6A), and MMP-9(-1562 C/T) polymorphism and susceptibility to idiopathic dilated cardiomyopathy (IDCM). DESIGN AND METHODS: MMP-1, -3, -9 genotypes were determined by PCR-RFLP analysis. RESULTS: Genotype frequency of MMP-3, but not MMP-1 and MMP-9 in IDCM patients, was significantly different from that in healthy controls. CONCLUSIONS: Our data suggested that MMP-3 5A/6A polymorphism could be a risk factor for the susceptibility to IDCM.