急性心肌梗死患者血清中miRNA-21的表达研究

Expression and clinical significance of mirna-21 in serum of patients with acute myocardial infarction

目的研究老年急性心肌梗死(acute myocardial infarction,AMI)患者血清中miRNA-21的表达,探讨血清miRNA-21作为早期心肌细胞损伤标记的潜在作用。方法研究中包括AMI的老年患者29例(AMI组),不稳定心绞痛(UA)的老年患者21例(UA组),以及健康的老年人18例(对照组)。血清miRNA-21是先RNA提取并反向转录到cDNA后,再进行RT-PCR测得。血清CK-MB和cTnI表达水平是由电化学发光分析得出。利用流式细胞仪测心肌细胞的凋亡。Western blot检测caspase-3蛋白等表达。结果老年AMI患者血清中miRNA-21的表达水平与血清CK-MB水平(r=0.3597,P<0.05),cTnI水平(r=0.5056,P<0.05)呈正相关。肿瘤坏死因子(TNF-α)诱导下转染shRNA模拟的miRNA-21与对照组心肌细胞相比,心肌细胞凋亡率下降了37.6%, JNK和p38的蛋白表达没有改变(P>0.05);p-JNK、p-p38和caspase-3的表达降低了36.5%、35.5%和37.1%。结论老年AMI患者血清中miRNA-21的表达通过激活JNK/p38/caspase-3信号通路抑制了TNF-α介导的心肌细胞凋亡。

Objective To investigate the Expression and clinical significance of mirna-21 in serum of elderly patients with acute myocardial infarction(AMI),and to explore the potential role of serum miRNA-21 as a marker of early cardiac myocyte damage.Methods A total of 29 elderly patients with AMI,21 elderly patients with unstable angina pectoris and 18 healthy elderly subjects were enrolled in the study.The expression levels of serum miRNA-21 were detected by reverse transcription-polymerase chain reaction(RT-PCR)after total RNA was extracted and reverse-transcribed into cDNA.The levels of serum creatine kinase MB isoenzyme(CK-MB)and cardiac troponin I(cTnI)were measured by electrochemiluminescence.Apoptosis of human cardiac myocytes(HCM)was detected by using fluorescenceactivatedcell sorting(FACS),and protein expression of caspase-3 was detected by using Western Blot.Results The expression levels of miRNA-21 in serum of elderly patients with AMI were positively correlated with those of of CK-MB(r=0.3597,P<0.05)and cTnI(r=0.5056,P<0.05).As compared with that in control group,the apoptosis rate of HCM transfected with the miRNA-21 mimic short hairpin RNA(shRNA)was decreased by 37.6%,however,there was no significant changes in the protein expression of c-Jun N-terminal kinases(JNK)and p38(P>0.05).Moreover the protein expression levels of p-JNK,p-p38 and caspase-3 were decreased by 36.5%,35.5%,and 37.1%,respectively.Conclusion The expression levels of miRNA-21 are upregulated in serum of elderly patients with AMI,which inhibits TNF-αinduced apoptosis in HCM by activating the JNK/p38/caspase-3 signaling pathway.