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【Objective】 To explore the distribution of polymorphisms of miR-208 genes rs8022522 and rs12894524 locus in Guangxi healthy population and compare the differences in the polymorphism distribution in different population. 【Methods】 SNPscan technology was used to detect genotypes of rs8022522 and rs12894524 from 297 healthy people in Guangxi, and the results were compared with other populations from Human genome Haplotype Map(HapMap) data. 【Results】 Three genotypes, namely, AA (2.7%), AG (24.2%) and GG (73.1%), in rs8022522 were found, with the allele frequencies of A and G being 14.8% and 85.2%. The genotypes of rs12894524 locus were TT (1.3%), TG (13.5%) and GG (85.2%), and the frequency of T and G allele was 8.1% and 91.9%, respectively. rs8022522 and rs12894524 locus genotypes and allele frequencies were significantly different from HapMap-CEU, HapMap- YRI and HapMap-TSI (P<0.05). Compared with HapMap-JPT and HapMap-CHB, there was no significant difference in genotype or allele frequency between the two sites (P>0.05). As for the blood lipid level among the three genotypes in rs8022522, the level of high density lipoprotein cholesterol (HDL-C) with GG genotype was significantly different from that in AG group (P<0.05). 【Conclusion】 The polymorphisms of rs8022522 and rs12894524 of miR-208 gene in Guangxi population are different from those in other regions to varying degrees. The polymorphism of rs8022522 locus is related to the level of HDL-C.
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ObjectiveTo investigate the effect of myosin heavy chain 7 gene-derived miRNA-208b-3p on the fibrotic phenotype of cardiac fibroblasts. MethodsmiRNA chip array was performed to detect the dysregulated miRNAs in the myocardium of diabetic db/db mice and db/m control mice. Neonatal mouse ventricular cardiomyocytes （NMVCs） and cardiac fibroblasts （CFs） were isolated from C57BL/6 mice and cultured. Real-time quantitative PCR （RT-qPCR） was conducted to determine the expression of miR-208b-3p in mouse CFs and NMVCs subjected to angiotensinⅡ（AngⅡ） and high glucose plus glucose oxidase （G/Go） treatment， respectively. Cell counting kit 8（CCk8） assay， flow cytometry and determination of fibrosis-related protein， including COL1A1， COL3A1and α-SMA， were performed in mCFs transfected with miR-208b-3p. Dual luciferase reporter assay was performed to confirm the interaction between miR-208b-3p and the 3'-UTR of metal response element binding transcription factor 2 （Mtf2） and progesterone receptor membrane component 1（Pgrmc1）， respectively. The expressions of Mtf2 and Pgrmc1 at the mRNA and protein levels in mCFs after miR-208b-3p mimic transfection were determined using RT-qPCR and Western blot assay， respectively. The small interfering RNA （siRNA） was used to inhibit Mtf2 and Pgrmc1 expression in mCFs， and the effects of Mtf2 siRNA， Pgrmc1 siRNA and miR-208b-3p on fibrosis-related protein expression in mCFs were investigated. ResultsResults of miRNA chip array and RT-qPCR assay showed that miR-208b-3p was up-regulated in the myocardium of the diabetic db/db mice. miR-208b precursor and the host gene of Myh7 were consistently increased in db/db mice. miR-208b-3p and Myh7 mRNA were expressed in mCFs and NMVCs， but the levels of miR-208b-3p and Myh7 mRNA in NMVCs were much higher than those in mCFs. miR-208b-3p was up-regulated in mCFs and NMVCs subjected to Ang Ⅱ and G/Go treatment， respectively. miR-208b-3p could significantly enhance fibrosis-related protein， including COL1A1， COL3A1 and α-SMA， in mCFs， without affecting the proliferation activity and cell cycle distribution of mCFs. Dual luciferase reporter assay revealed the interactions of miR-208b-3p with the 3'-UTR of Mtf2 and Pgrmc1. The results of RT-qPCR and Western blotting confirmed that miR-208b-3p inhibited Mtf2 and Pgrmc1 expression at the post- transcriptional level. Transfection with miR-208b-3p mimic， Mtf2 siRNA and Pgrmc1 siRNA could consistently enhance the fibrosis-related protein expression in the cardiac fibroblasts. ConclusionsmiR-208b-3p enhances fibrosis-related gene expression by targeting Mtf2 and Pgrmc1in mCFs.
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Objectives: To investigate whether remote ischemic conditioning (RIC) applied to patients with ST-segment elevation myocardial infarction (STEMI) before percutaneous coronary intervention (PCI) could affect circulating miR-208b level or not. Methods:Patients diagnosed with STEMI undergoing PCI from January 2016 to July 2017 were enrolled from the Department of Cardiology, Affiliated Zhongshan Hospital of Dalian University.The patients were randomly allocated to two groups: (1) control group (n=25), PCI alone; (2) RIC group (n=50), PCI combined with RIC (three cycles of 5 min inflation and 5 min deflation of the right lower limb with blood pressure cuff performed before reperfusion). Serum miR-208b was measured before and immediately, at 24 h, and 48 h after PCI with real-time quantitative polymerase chain reaction. Results: The expression of miR-208b was significantly higher immediately post PCI than that before operation in the control group (84.1±9.0 vs 77.8±9.4; P=0.032), while it was significantly lower immediately post PCI than that before operationin RIC group (71.0±9.3 vs 77.4±8.8; P=0.028).miR-208b level was similar before PCI between the control and RIC groups (P=0.874), which was significantly reduced immediately post PCI in RIC group as compared with the control group (P=0.021).The peak value of creatine kinase isoenzyme (CK-MB) in the limb RIC group was significantly lower than that in the control group ([135.2±18.6] U/L vs [167.7±17.2] U/L; P=0.038).The area under the CK-MB curve of the RIC group was significantly smaller than that of the control group ([3 060.7±17.1] U/L vs [3 635.9±15.1] U/L); P=0.047]. The left ventricular ejection fraction (LVEF) in RIC group was significantly higher than that in the control group ([57.8±7.8]% vs [51.9±7.9]%; P=0.003) post PCI. The expression level of serum miR-208b was positively correlated with CK-MB AUC in RIC group (r=0.498, P<0.001). Conclusions: RIC of the lower limb prior to PCI could reduce miR-208b level and improve cardiac functionin STEMI patients.
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Objective To investigate the role of miR-208b-3p in dexmedetomidine(DEX) alleviating rat myocardial ischemia reperfusion injury(MIRI).Methods Eighty adult male Wister rats were divided into the sham operation(Sham) group,I/R group,DEX group and miR-208b-3p+ DEX group.In the Sham group,a 6-0 silk suture was only placed without ligation,and other 3 groups were treated by I/R model.Before ischemia reperfusion,the DEX group received a loading dose of DEX(5 μg/kg) via the femoral vein followed by a continuous infusion of 5 μg · kg-1 · h-1 for 1 h.In the miR-208b-3p+ DEX group,rats received intramuscular injection of miR-208b-3p analogue at 24 h before ischemia reperfusion.The cardiac function indexes were monitored at 120 min after reperfusion,including heart rate(HR),left ventricular systolic blood pressure(LVSP),left ventricular end diastolic pressure(LVEDP) and left ventricular rate maximum(dp/dtmax).The serum levels of cTn-Ⅰ and CK-MB were detected and the apoptosis rate(AI) was measured by in situ apoptosis assay.The levels of oxidative stress related indicators were detected and Western blot was used to detect the level of myocardial apoptosis protein.Results Compared with the Sham group,the cardiac function in the I/R group was decreased,but the levels of CTn-Ⅰ,CK-MB,AI,MDA,Bax and Caspase-3 were increased(P＜0.05);compared with the I/R group,the above indexes in the DEX group were improved(P＜0.05);compared with the DEX group,the above indexes in the miR-208b-3p+DEX group were deteriorated(P＜0.05).Conclusion Overexpression of miR-208b-3p can eliminate the protective effect of DEX on MIRI.