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Objective To explore the effect of microRNA-22-3p (miR-22-3p) regulating the expression of Kruppel-like factor 6 (KLF6) on the cardiomyocyte-like differentiation of bone marrow mesenchymal stem cell (BMSC). Methods Rat BMSC was isolated and cultured,and the third-generation BMSC was divided into a control group,a 5-azacytidine(5-AZA)group,a mimics-NC group,a miR-22-3p mimics group,a miR-22-3p mimics+pcDNA group,and a miR-22-3p mimics+pcDNA-KLF6 group.Real-time fluorescent quantitative PCR (qRT-PCR) was carried out to determine the expression of miR-22-3p and KLF6 in cells.Immunofluorescence staining was employed to detect the expression of Desmin,cardiac troponin T (cTnT),and connexin 43 (Cx43).Western blotting was employed to determine the protein levels of cTnT,Cx43,Desmin,and KLF6,and flow cytometry to detect the apoptosis of BMSC.The targeting relationship between miR-22-3p and KLF6 was analyzed by dual luciferase reporter gene assay. Results Compared with the control group,5-AZA up-regulated the expression of miR-22-3p ( q =7.971, P <0.001),Desmin ( q =7.876, P <0.001),cTnT ( q =10.272, P <0.001),and Cx43 ( q =6.256, P <0.001),increased the apoptosis rate of BMSC ( q =12.708, P <0.001),and down-regulated the mRNA ( q =20.850, P <0.001) and protein ( q =11.080, P <0.001) levels of KLF6.Compared with the 5-AZA group and the mimics-NC group,miR-22-3p mimics up-regulated the expression of miR-22-3p ( q =3.591, P <0.001; q =11.650, P <0.001),Desmin ( q =5.975, P <0.001; q =13.579, P <0.001),cTnT ( q =7.133, P <0.001; q =17.548, P <0.001),and Cx43 ( q =4.571, P =0.037; q =11.068, P <0.001),and down-regulated the mRNA ( q =7.384, P <0.001; q =28.234, P <0.001) and protein ( q =4.594, P =0.036; q =15.945, P <0.001) levels of KLF6.The apoptosis rate of miR-22-3p mimics group was lower than that of 5-AZA group ( q =8.216, P <0.001).Compared with the miR-22-3p mimics+pcDNA group,miR-22-3p mimics+pcDNA-KLF6 up-regulated the mRNA( q =23.891, P <0.001) and protein( q =13.378, P <0.001)levels of KLF6,down-regulated the expression of Desmin ( q =9.505, P <0.001),cTnT ( q =10.985, P <0.001),and Cx43 ( q =8.301, P <0.001),and increased the apoptosis rate ( q =4.713, P =0.029).The dual luciferase reporter gene experiment demonstrated that KLF6 was a potential target gene of miR-22-3p. Conclusion MiR-22-3p promotes cardiomyocyte-like differentiation of BMSC by inhibiting the expression of KLF6.

Background: MicroRNAs (miRNAs) play key roles in cardiac development, and the expression of miRNAs is altered in the diseased heart. The aim of this study was to explore the value of circulating microRNA-122-5p (miR-122-5p) as a potential biomarker for acute myocardial infarction (AMI)., Methods: Plasma samples from 50 patients with AMI and 39 healthy adults (non-AMI controls) were collected. The abundance of circulating miR-122-5p was measured using quantitative real-time PCR (qRT-PCR). The cTnI concentrations of these samples were analyzed by ELISA., Results: Our findings revealed that circulating miR-122-5p expression were increased in AMI patients at 4 h, 8 h, 12 h, and 24 h by contrast to those non-AMI controls and displayed similar trends to that of cTnI concentrations in AMI patients. Further study showed that there is a high correlation between circulating miR-122-5p and cTnI concentrations. At last, the receiver operating characteristic (ROC) curve was performed and showed that circulating miR-122-5p had considerable diagnostic accuracy for AMI with an area under curve (AUC) of 0.855., Conclusions: Our results implied that circulating miR-122-5p could be a potential biomarker for AMI.

Melanoma is a malignant cutaneous cancer of high metastasis and lethal rates. Epithelial-mesenchymal transition (EMT) plays an important role in the embryonic developmental process that is often activated during tumorigenesis and metastasis. In this study, we integrated of mRNA and miRNA transcriptome sequencing data of melanocyte and melanoma cell lines to identify genes involved in the process of tumor EMT in the first place, and uncovered 11 miRNAs including miR-130a-3p, miR-130b-3p, miR-125a-5p, miR-30a-3p, miR-195-5p, miR-345-5p, miR-509-3-5p, miR-374a-5p, miR-509-5p, miR-148a-3p and miR-330-3p, negatively related with EMT genes using the Mirsystem software. Bioinformatics analysis with target genes of these miRNAs revealed two networks closely related with cellular development and cell-to-cell interactions, as well as multiple signaling pathways participating in EMT. Validation of the 11 miRNAs with molecular biology experiments demonstrated that four miRNAs regulated oncogenes in melanomas, including miR-195-5p, miR-130a-3p, miR-509-5p, and miR-509-3-5p. Our study integrates two kinds of omics data to screen for EMT-related miRNAs, providing a new research idea in the precision genomics of cancer research.