Crosstalk between PKR1 and miR-124 is crucial for EMT regulation of tc21+epicardial mesothelial cells during cardiac development and repair process

Abstract Background The epicardial-mesothelial cells (EMCs) are essential regulators of cardiac growth and repairment process. epicardial-to-mesenchymal transition (EMT) epicardial fate determination controlled by both cell autonomous cardiomyocyte-originated mechanisms. Here, using an in vitro vivo model EMT, we investigated the role miRNAs as these process their potential targets. Methods EMT was induced mice embryonic tcf21+EMCs through angiogenic cytokine, prokineticin treatments. Cre-dependent tracing TCF21-tm-iCRE-EMCs utilized to abrogate receptor-1 (PKR1) epicardium. Human tcf21+ fibroblast (mainly originated from origin also study for signaling. Results Upon EMC-specific abrogation PKR1 early stages development TCF21-tm-iCREPKR1−/− exhibited 13±4% lethality due a disconnection compact layer, failed expansion sub-epicardial space, disruption heterotypic interaction between epicardium myocardium. EMT-RT profiler enrichment analysis revealed impaired hearts. Ingenuity Pathway Analysis on molecular network (e.g., Snai1, Snai2, B-catenin, N-cadherin, vimentin), specific defects MiR-124 part this that inversely associated down-stream cultured Tcf21+ cells. Furthermore, protein expression SNAIL2 significantly downregulated hearts upon treatment with mir124 mimic. luciferase reporter assay showed miR124 directly targeted 3'-untranslated region EMCs. In counter experiment, gene replacement or inhibitor able rescue EMT-genes, increase apoptosis proliferation Importantly, miRNA mimic tcf21 maintained epithelial features EMCs, increased EMT-associated transcripts traits, such apoptosis. contrast, MiR124 is involved wound healing tcf21+human CFs Conclusion This shows importance crosstalk miR-124 respect regulation during repair. Controlling fibroblast-committed pathological fibrotic remodeling increasing interest within field regenerative tissue engineering interventional strategies after injury. Funding Acknowledgement Type funding sources: Foundation. Main source(s): Fondation de France