Search

• Improving the conversion efficiency of CFs to cardiac myocytes is a challenging task. • The appearance of fibrotic prevents cardiac reprogramming. • Inhibition of pro-fibrotic signalling by the TGF-β receptor inhibitor enhances the reprogramming of CFs to iCMs. Recent studies have shown that cardiac fibroblasts (CFs) can be transformed into induced cardiomyocytes (iCMs). This phenomenon represents a potential method for rescuing damaged myocardia after myocardial infarction. The mechanism underlying cardiac reprogramming regulation must be clarified to improve the induction efficiency of iCMs. In this study, we treated CFs with 5-aza for 24 h and added TGF-β inhibitor A83-01 for 2 weeks in vitro to investigate the effect of inhibiting fibrosis on myocardial differentiation. Inhibition of TGF-β1 activity with A83-01 significantly decreased the expressions of collagen III and α-SMA and increased the expression of myocardial specific marker cTnT and gap junction protein Cx43 in CFs, enhanced cardiac reprogramming as opposed to 2 weeks with 5-aza alone. Transcriptome and quantitative real-time reverse transcription-polymerase chain reaction analysis at the 14th day postinduction of A83-01 revealed that the expression of genes involved in cardiac development increased in the presence of 5-aza. These findings suggest that the addition of A83-01 remarkably inhibits profibrotic signalling and improved the efficiency of iCMs, provide new insights into the molecular mechanisms of cardiac reprogramming and promote the use of iCMs in clinical applications. [ABSTRACT FROM AUTHOR]

Objective To explore the differentiation tendency of CD90 + cardiac fibroblast (CFs) into cardiomyogenic cells in vitro and repair functions in acute myocardial infarction rats. Methods CD90 + subpopulation was sorted from rat CFs by flow cytometry. 10 μmoL/L of 5-Azacytosine (5-aza) was used to induce differentiation of CFs into cardiomyogenic cells. An acute myocardial infarction model was prepared by ligation of the rat left anterior descending coronary artery. After nuclei were labeled by DAPI, induced CD90 + CFs were injected into the infarction marginal zone. Before coronary ligation, 40 min after ligation, and at 7 and 14 days after cell transplantation, cardiac function changes were detected by ultrasound imaging system respectively. cTnT and endothelial cell marker VIII factor were detected by immunofluorescence staining. Infarct size was examined by TTC staining. Fibrosis was evaluated with masson’s trichrome staining, vimentin, type I and type III collagen staining. Results CD90 + CFs sorted by flow cytometry was 34.9%. On day 28 after induction, the cTnT positive rate was 61.17 ± 9.75%. Left ventricular ejection fraction (LVEF) and left ventricular fractional shortening (LVFS) at days 7 and 14 after transplantation were significantly increased compared with those before transplantation (P < 0.05). LVEF and LVFS at the 14th day after transplantation were also significantly increased compared with those at the 7th day (LVEF: 61.40 ± 2.45% vs . 56.25 ± 2.9%, LVFS: 33.21 ± 0.68% vs . 30.26 ± 2.06%, P < 0.01). Additionally, small numbers of CD90 + CFs differentiated into cardiomyocytes and became involved in neovascularization. CD90 + CFs and CFs reduced myocardial infarct size at days 14. It was significantly smaller in rats with CFs transplantation group than those in MI group(24.78 ± 2.28% vs . 31.28 ± 2.83%, P < 0.05), and it was also significantly smaller in rats with CD90 + CFs transplantation group than those in CFs transplantation group (17.47 ± 4.15% vs . 24.78 ± 2.28%, P < 0.05). Meanwhile, The percentage of fibrotic area and vimentin, type I and type III collagen in the infarct border zone and infarct area were both significantly reduced in CD90 + CFs. Conclusion CD90 + CFs is the preponderant subpopulation of cardiomyogenic differentiation, with potential use as seed cells in basic and clinical research of heart regeneration and repair. [ABSTRACT FROM AUTHOR]