RESUMEN
Objective: This study aimed to explore the role of circular RNAs (circRNAs) in M2 macrophage (M2M)-derived small extracellular vesicles (SEVs) in myocardial fibrosis development. Methods: The regulatory role of M2M-derived extracellular vesicles (EVs) was evaluated in a mouse model of acute myocardial infarction. Immunofluorescence, quantitative real-time PCR (RT-qPCR), nanoparticle tracking analysis, Western blot analysis and electron microscopy were used to identify macrophages, large extracellular vesicles (LEVs) and SEVs. The circRNA expression profiles of M0 macrophages (M0Ms) and M2Ms were determined by microarray analysis. Bioinformatic analysis, cell coculture and cell proliferation assays were performed to investigate the expression, function, and regulatory mechanisms of circUbe3a in vitro. qPCR, RNA immunoprecipitation (RIP), dual-luciferase reporter assays, RNA fluorescence in situ hybridization (RNA-FISH), Western blot analysis and a series of rescue experiments were used to verify the correlation among circUbe3a, miR-138-5p and RhoC. Results: CircUbe3a from M2M-derived SEVs triggered functional changes in cardiac fibroblasts (CFs). CircUbe3a was synthesized and loaded into SEVs during increased M2M infiltration after myocardial infarction. The fusion of the released SEVs with the plasma membrane likely caused the release of circUbe3a into the cytosol of CFs. Silencing or overexpressing circUbe3a altered CF proliferation, migration, and phenotypic transformation in vitro. We confirmed that circUbe3a plays a crucial role in enhancing functional changes in CFs by sponging miR-138-5p and then translationally repressing RhoC in vitro. In vivo, the addition of M2M-derived SEVs or overexpression of circUbe3a significantly exacerbated myocardial fibrosis after acute myocardial infarction, and these effects were partially abolished by circUbe3a-specific shRNA. Conclusions: Our findings suggest that M2M-derived circUbe3a-containing SEVs promote the proliferation, migration, and phenotypic transformation of CFs by directly targeting the miR-138-5p/RhoC axis, which may also exacerbate myocardial fibrosis after acute myocardial infarction.
Asunto(s)
Vesículas Extracelulares/química , Macrófagos/metabolismo , Infarto del Miocardio/patología , Miocardio/patología , ARN Circular/genética , Animales , División Celular , Movimiento Celular , Fibroblastos/metabolismo , Fibrosis , Humanos , Ratones , MicroARNs/antagonistas & inhibidores , MicroARNs/genética , Infarto del Miocardio/genética , Miocardio/metabolismo , Interferencia de ARN , ARN Interferente Pequeño/genética , Remodelación Ventricular , Proteína rhoC de Unión a GTP/fisiologíaRESUMEN
Previous studies have shown that 4.1 proteins, which are deregulated in many cancers, contribute to cell adhesion and motility. Yurt/Mosaic eyes-like 1 (YMO1) is a member of 4.1 protein family but it is unclear whether YMO1 plays a role in tumor invasion. This study aimed to investigate the effects of YMO1 on hepatocellular carcinoma (HCC) and attempted to elucidate the underlying molecular mechanisms. YMO1 expression in HCC tissues and its correlation with clinicopathological features and postoperative prognosis was analyzed. The results showed that YMO1 was down-regulated in the highly metastatic HCC cell line and in human tumor tissues. Underexpression of YMO1 indicated poor prognosis of HCC patients. Restoration of YMO1 expression caused a significant decrease in cell migration and invasiveness in vitro. In vivo study showed that YMO1 reduced liver tumor invasion and metastasis in xenograft mice. YMO1 directly inhibited RhoC activation. YMO1 expression in HCC was regulated by PAX5. Analysis of YMO1 expression levels in human HCC patients revealed a significant correlation of YMO1 expression with PAX5 and RhoC. Our findings revealed that YMO1 predicts favorable prognosis and the data suggest that YMO1 suppresses tumor invasion and metastasis by inhibiting RhoC activity.