Erythropoietin helix B surface peptide modulates miR-21/Atg12 axis to alleviates cardiomyocyte hypoxia-reoxygenation injury.
ABSTRACT: BACKGROUND:The erythropoietin helix B surface peptide (HBSP) has been shown to have neuroprotective and repair-damaging myocardium effects similar to erythropoietin (EPO). However, the protective mechanism of HBSP on cardiomyocyte hypoxia-reoxygenation (H/R) injury is not clear. METHODS:H9C2 cells were pretreated with HBSP and subjected to hypoxia/reoxygenation (H/R), changes in cell function, autophagy and apoptosis were assessed, respectively. Cells were transfected with miR-21 mimic and miR-NC, and the relative expression of miR-21 and Atg12 were detected by qRT-PCR. The target role of miR-21 and Atg12 was evaluated by dual-luciferase reporter. After transfected with si-Atg12 and si-NC, western blot was used to assess autophagy and apoptosis proteins, flow cytometry assay was used to detect apoptosis rate. RESULTS:We found the expression of miR-21 was significantly down-regulated, accompanied by remarkably activated of autophagy and apoptosis in H9C2 cells during H/R injury. Pleasantly, HBSP pretreatment has a similar effect as transfection of miR-21 mimic, which is to evidently inhibit autophagy and apoptosis by up-regulating miR-21 expression. Moreover, Bioinformatics analysis and luciferase reporter assay revealed that Atg12 was directly bond to miR-21. To further understand whether Atg12 is involved in the process of miR-21 regulating autophagy, si-Atg12 and si-NC were transfected into H9C2 cell, the results showed that knockdown of Atg12 enhances the inhibition autophagy and apoptosis effect of HBSP. CONCLUSION:These results demonstrate that HBSP inhibits myocardial H/R injury induced by autophagy over-activation and apoptosis via miR-21/Atg12 axis.
Project description:Recent evidence suggests that hypoxia caused by acute myocardial infarction can induce cardiomyocyte apoptosis. Exosomes are signalling mediators that contribute to intercellular communication by transporting cytosolic components including miRNAs, mRNAs, and proteins. However, the systemic regulation and function of exosomal miRNAs in hypoxic cardiomyocytes are currently not well understood. Here, we used small RNA sequencing to investigate the effects of hypoxia stress on miRNAome of rat cardiomyoblast cells (H9c2) and corresponding exosomes. We identified 92 and 62 miRNAs in cells and exosomes, respectively, that were differentially expressed between hypoxia and normoxia. Hypoxia strongly modulated expression of hypoxia-associated miRNAs in H9c2 cells, and altered the miRNAome of H9c2 cells-derived exosomes. Functional enrichment analysis revealed extensive roles of differentially expressed exosomal miRNAs in the HIF-1 signalling pathway and in apoptosis-related pathways including the TNF, MAPK, and mTOR pathways. Furthermore, gain- and loss-of-function analysis demonstrated potential anti-apoptotic effects of the hypoxia-induced exosomal miRNAs, including miR-21-5p, miR-378-3p, miR-152-3p, and let-7i-5p; luciferase reporter assay confirmed that Atg12 and Faslg are targets of miR-152-3p and let-7i-5p, respectively. To summarize, this study revealed that hypoxia-induced exosomes derived from H9c2 cells loaded cardioprotective miRNAs, which mitigate hypoxia-induced H9c2 cells apoptosis.
Project description:Chronic obstructive pulmonary disease (COPD) has become a significant public health risk. Long non-coding RNAs (lncRNAs) have been identified as important factors involved in the proliferation, apoptosis and inflammatory cytokine expression of lung cells. Peripheral blood samples from 66 subjects (18 non-smokers, 24 smokers without COPD and 28 smokers with COPD) and HBE135-E6E7 cell treated with cigarette smoke extract (CSE) or not were used as the research object. The aim of the present study was to investigate the underlying mechanism of lncRNA maternally expressed gene 3 (MEG3) in COPD. Following transfection with microRNA (miR)-149-3p mimics, miR-negative control mimics, miR-149-3p inhibitor, miR-negative control inhibitor, small interfering (si)RNA targeting MEG3 (si-MEG3) and si-negative control (si-NC), levels of MEG3 and microRNA (miR)-149-3p were detected using reverse transcription-quantitative PCR, Proliferation and apoptosis were examined using the Cell Counting Kit-8 and flow cytometry assays, respectively. Enzyme-linked immunosorbent assay (ELISA) was performed to detect the expression of interleukin-6 (IL-6) and tumor necrosis factor-? (TNF-?). Protein levels of B-cell lymphoma-2 (Bcl-2), cleaved-caspase-3, cleaved-caspase-9, phosphorylated (p)-p65, total (t)-p65, p-lkB? and t-lkB? were measured by western blotting. Luciferase assay was conducted to examine the relationship between MEG3 and miR-149-3p. LncRNA MEG3 was highly expressed, whereas miR-149-3p expression was downregulated in smokers with COPD peripheral blood samples, compared with non-smokers and smokers without COPD samples. Compared with untreated human bronchial epithelial (HBE) cells, MEG3 expression was increased in cigarette smoke extract (CSE)-treated HBE cells. Compared with CSE-treated HBE cells transfected with si-NC, MEG3 knockdown promoted cell proliferation and inhibited apoptosis in CSE-treated HBE cells transfected with si-MEG3, and it also decreased the levels of IL-6, TNF-?, Bcl-2 and increased cleaved-caspase-3 and cleaved-caspase-9 in CSE-treated HBE cells transfected with si-MEG3. The luciferase assay demonstrated that miR-149-3p has target sites for MEG3. MEG3 was demonstrated to regulate the NF-?B signaling pathway by sponging miR-149-3p in CSE-treated HBE cells. In conclusion, these findings suggested that MEG3 promoted proliferation and inhibited apoptosis by regulating the NF-?B signal pathway via miR-149-3p in CSE-treated HBE cells. These results provide an insight for further verification and understanding of the molecular basis of COPD.
Project description:Recent evidence suggests that hypoxia caused by acute myocardial infarction (AMI) can induce evident cardiomyocyte apoptosis. Exosomes, as paracrine signaling mediators by delivering cytosolic components (including miRNA, mRNA, protein), play crucial roles in intercellular communication. However, the systemic regulation of exosome-mediated miRNA delivery and subsequent regulation effect underlying AMI are not well-understood to date. Here, using small RNA-seq, we investigated the miRNAome of H9C2 cells and corresponding paracrine exosmes after hypoxia stress, and identified total of 92 and 62 differentially expressed (DE) miRNAs in cells and exosomes from hypoxia vs. normoxia condition. We found that hypoxia strongly induced the expression of hypoxamiRs in H9C2 cells and altered cardiomyocyte-derived exosomal miRNAome. Functional enrichment analysis revealed extensive roles of DE exosomal miRNAs in HIF-1 signaling pathway and cell apoptosis process, such as TNF signaling pathway, MAPK signaling pathway, mTOR signaling pathway. Furthermore, the gain- and loss-of-function analysis demonstrated the anti-apoptotic effects of hypoxia-induced exosomal miRNAs, i.e. miR-21-5p, miR-378-3p, miR-152-3p, let-7i-5p, and then the luciferase reporter assay confirmed that miR-152-3p and let-7i-5p implemented their anti-apoptotic function by directly targeting Atg12 and Faslg, respectively. In short, this study revealed that hypoxia-exosomes derived from cardiomyocyte, loaded abundant cardio-protective miRNAs, mediate crosstalk among cardiomyocytes and prevent cardiomyocytes apoptosis after hypoxia. Methods: we established the anoxia model using H9C2 cells, an immortal cardiac muscle cell line, to imitate hypoxia condition caused by AMI in vitro, and then small RNA-seq were employed to investigate the miRNA transcriptome of H9C2 cells and its exosomes collected from hypoxia and normoxia culture medium. Results: we identified the miRNAome of H9C2 cells and its exosmes under both hypoxia and normoxia, including 331, 338, 144, 74 unique mature miRNAs from hypoxia-cells, normoxia-cells, hypoxia-exosomes, normoxia-exosomes, respectively. Total of 92 and 62 DE miRNAs were identified from cells and exosomes. Among of which, the DE exosomal miRNAs were mainly involved in HIF-1 signaling pathway and cell apoptosis process, such as TNF signaling pathway, MAPK signaling pathway, mTOR signaling pathway. Interestingly, we found that some DE exosomal miRNAs, including miR-21-5p, miR-378-3p, miR-152-3p, let-7i-5p, have an anti-apoptotic and pro-viability effects in H9C2 cells under hypoxic stress. In addition, Atg12 and Faslg to be respective target of miR-152-3p and let-7i-5p were partly elucidated the anti-apoptosis mechanism of hypoxia-exosomes. Conclusions:In brief, this study illustrated a potential mechanism that, under hypoxic stress, hypoxia pre-perceived cardiomyocytes can spontaneously secrete the hypoxamiRs enriched exosomes, loaded a large amount of cardio-protective miRNA, which mediate crosstalk among cardiomyocytes and prevent apoptosis to heighten the hypoxia adaptability of cardiomyocytes. In more detail, we first discovered that miR-152-3p and let-7i-5p, enriched in hypoxia-exosomes derived by cardiomyocytes, played an anti-apoptosis role via mitochondrial pathway(intrinsic pathway) and death receptor pathway (extrinsic pathway), respectively. Overall design: miRNA transcriptome of H9C2 cells and its exosomes collected from hypoxia and normoxia culture medium
Project description:Helix B surface peptide (HBSP) is an erythropoietin (EPO)-derived peptide that protects tissue from the risks of elevated blood pressure and thrombosis. This study focused on the protection of HBSP in hepatic ischaemia/reperfusion (I/R) by enhancing the level of autophagy. In detail, we randomly divided C57BL/6 mice into sham-operated, hepatic ischaemia/reperfusion (I/R), I/R?+?HBSP, I/R?+?HBSP?+?3-methyladenine (autophagy inhibitor), I/R?+?HBSP?+?rapamycin (mTOR inhibitor), and I/R?+?HBSP?+?Ly294002 (Akt inhibitor) groups. We assessed alanine aminotransferase (ALT), aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) levels in mouse sera, and performed haematoxylin/eosin (HE) staining, immunohistochemistry, electron microscopy, immunofluorescence microscopy, and western blotting on liver tissue to detect the degree of liver injury, liver apoptosis, autophagy, and the expression of microtubule associated protein 1 light chain 3 alpha (Map1lc3, or LC3), Beclin 1, phospho-mTOR, mTOR, phospho-Akt (P-Akt), and Akt. HBSP relieved hepatic I/R injury in a concentration-independent manner. The expression of LC3II, LC3I, and Beclin 1, and the formation of autophagosomes, in the I/R?+?HBSP group were higher than those in the I/R group. The protective effects of HBSP were abolished by 3-methyladenine and, to a lesser extent, Ly294002, but enhanced by rapamycin. Furthermore, In vivo, HBSP also protected against hypoxia injury induced by cobalt chloride (CoCl2) through improving the level of autophagy. Therefore, HBSP protected against hepatic I/R injury, mainly via regulating autophagy by targeting mTOR.
Project description:BACKGROUND:Remote ischemic postconditioning (RIPostC) is an effective strategy for preventing key organs from becoming impaired due to an ischemia/reperfusion injury. In the current study, we investigated how remote exosome transfer of microRNAs (miRs) may contribute to the treatment effect of RIPostC on the central nerve system (CNS). METHODS:Human umbilical vein endothelial cells (HUVECs) were subjected to hypoxia/reoxygenation (H/R) and their miR expression profiles were investigated using the microarray method. The pathways associated with dysregulated miRs were analyzed by gene ontology (GO) annotation of the target genes and a Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis. The role played by the most significantly down-regulated miR (miR-21-3p) in the protective effect of HUVEC-derived exosomes on H/R-treated neural cells was further investigated. The pathway mediating the effect of miR-21-3p was then explored by focusing on activity of autophagy-related 12 (ATG12) protein. RESULTS:The miR expression profile of HUVECs significantly changed after H/R administration, with 104 miRs becoming upregulated and 249 miRs becoming downregulated. Based on the GO and KEGG analyses, the target genes of 8 selected miRs were involved in multiple biological pathways, including the hippo signaling pathway and longevity regulating pathway. Further studies showed that inhibition of miR-21-3p by HUVEC-derived exosomes or a specific inhibitor could the block apoptotic process in H/R-treated neural cells. Molecular level studies showed that the effect of miR-21-3p inhibition depended on the restored function of ATG12, which resulted in the activation of autophagy and suppression of apoptosis. CONCLUSION:Taken together, these results suggest that H/R caused significant changes of miR expression in exosomes derived from H/R-treated HUVECs, and the exosomes protect neurons against H/R-induced injuries by suppressing miR-21-3p.
Project description:The research aims to explore the roles and regulatory mechanisms of the circular RNA (circRNA) ZNF292 (circZNF292) in OGD-induced damage in H9c2 cells. The H9c2 cells were treated by OGD and/or transfected with circZNF292, si-circZNF292, pc-Bcl-2/adenovirus E1B-19 kDa-interacting protein 3 (BNIP3) or corresponding controls. Cell viability was detected with the CCK-8. The protein expression levels of the Bax, caspase-3, Beclin-1, p62, LC3, BNIP3, Wnt3a, ?-catenin and mammalian target of rapamycin (mTOR) were individually determined via western blot. qRT-PCR was used to examine the circZNF292 expression level. The apoptotic rate was determined by the Annexin V-FITC/PI with flow cytometer. The production of the circZNF292 was promoted by OGD. Abundant circZNF292 released OGD-induced damage by up-regulating cell viability and Wnt3a/?-catenin or mTOR proteins, but down-regulating apoptosis and autophagy. circZNF292 had an opposite effect on these elements mentioned above. Besides, BNIP3 was negatively adjusted by the circZNF292. The BNIP3 overproduction destroyed the protective effect of circZNF292 on H9c2. circZNF292 released OGD-induced damage in the H9c2 cells by targeting the BNIP3 through Wnt/?-catenin and mTOR activation.
Project description:Acute myocardial infarction (AMI) is an ischemic heart disease with high mortality worldwide. AMI triggers a hypoxic microenvironment and induces extensive myocardial injury, including autophagy and apoptosis. MiRNAs, which are a class of posttranscriptional regulators, have been shown to be involved in the development of ischemic heart diseases. We have previously reported that hypoxia significantly alters the miRNA transcriptome in rat cardiomyoblast cells (H9c2), including miR-27a-5p. In the present study, we further investigated the potential function of miR-27a-5p in the cardiomyocyte response to hypoxia, and showed that miR-27a-5p expression was downregulated in the H9c2 cells at different hypoxia-exposed timepoints and the myocardium of a rat AMI model. Follow-up experiments revealed that miR-27a-5p attenuated hypoxia-induced cardiomyocyte injury by regulating autophagy and apoptosis via <i>Atg7</i>, which partly elucidated the anti-hypoxic injury effects of miR-27a-5p. Taken together, this study shows that miR-27a-5p has a cardioprotective effect on hypoxia-induced H9c2 cell injury, suggesting it may be a novel target for the treatment of hypoxia-related heart diseases.
Project description:Autophagy and apoptosis are associated with cardiovascular diseases. Emerging evidence shows that microRNAs (miRs) are critical in the development of pathological processes underlying cardiovascular diseases by regulating the induction of apoptosis and autophagy. The present study aimed to investigate the role of miR?103a?3p in cardiomyocyte injury through autophagy and apoptosis. H9c2 cells were cultured under hypoxia and reoxygenation (H/R) conditions and were used to mimic cells under ischemia. The transfection of cells with miR?103a?3p (mimics and inhibitors) was performed to examine its function in cardiomyocytes. The expression levels of miR?103a?3p were evaluated by reverse transcription?quantitative polymerase chain reaction analysis. Cell viability was determined using an MTT assay, and the lactate dehydrogenase assay (LDH) was used to investigate cell injury. The expression levels of B?cell lymphoma 2 (Bcl?2), Bcl?2?associated X protein, Beclin?1, autophagy?related 5 (Atg5), cleaved caspase?3 and cleaved caspase?9 were detected using western blotting. Immunofluorescence assays were performed to detect the expression of LC3 as a marker of autophagy. The target gene of miR?103a?3p was identified using dual?luciferase reporter assays. The results revealed that the expression levels of miR?103a?3p were significantly downregulated in cardiomyocytes under H/R conditions. Injury of the cardiomyocytes was evaluated under H/R conditions. Following transfection of the cells with miR?103a?3p inhibitors, cell injury was increased, as determined by LDH and MTT assays. The expression levels of apoptotic proteins were consistent with the results obtained in the LDH and cell viability assays. The induction of autophagy was increased in cells under H/R conditions and cells with miR?103a?3p inhibitor transfection, whereas the induction of autophagy was decreased in cells transfected with miR?103a?3p mimics. In addition, the data indicated that miR?103a?3p directly targeted Atg5, which regulated the induction of autophagy and apoptosis. Taken together, these findings indicate that, following the inhibition of miR?103a?3p, Atg5 promotes autophagy and apoptosis in cardiomyocytes by directly targeting Atg5. Therefore, miR?103a?3p can be considered a potential therapeutic target for myocardial ischemia.
Project description:Chemoresistance remains a major clinical problem in combating human lung adenocarcinoma (LAD), and abnormal autophagy is closely associated with this phenomenon. In the present study, an inverse correlation between miR-200b and autophagy-associated gene 12 (ATG12) expressions was observed in docetaxel-resistant (SPC-A1/DTX and H1299/DTX) and sensitive (SPC-A1 and H1299) LAD cells as well as in tissue samples. Further study showed that miR-200b directly targeted ATG12 in LAD. Moreover, miR-200b-dependent ATG12 downregulation inhibited autophagy and enhanced the chemosensitivity of SPC-A1/DTX and H1299/DTX cells both in vivo and in vitro. LAD chemoresistance is therefore closely related to downregulation of miR-200b and the corresponding upregulation of ATG12. These results provide new evidence for the mechanisms governing the microRNA (miRNA)-ATG12 network and their possible contribution to autophagy modulation and LAD chemoresistance.
Project description:Background: Doxorubicin (DOX) is one of the widely used anti-cancer drugs, whereas it can induce irreversible cardiac injury in a dose-dependent manner which limits its utility in clinic. Our study aimed to investigate the relationship between miR-25 and DOX-induced cardiac injury and its underlying mechanism. Methods: Mice and H9c2 cells were exposed to DOX. The overexpressed or knockdown of miR-25 in H9c2 cells was achieved by miR-25 mimic or inhibitor and the efficiency of transfection was identified by qRT-PCR or Western blotting. Cell viability, apoptotic cell rate, and levels of apoptosis-related proteins were determined by CCK-8, flow cytometry, and Western blotting, respectively. Furthermore, Western blotting and immunofluorescence staining (IF) were performed to assess the expression levels of reactive oxygen species and degree of DNA damage. Results: As a result, DOX significantly upregulated miR-25 expression in mice and H9c2 cells and reduced cell viability and increased cell apoptosis in vitro and in vivo. miR-25 overexpression expedited cell injury induced by DOX in H9c2 cells demonstrated by the increased cell apoptosis and reactive oxygen species (ROS) production, whereas miR-25 inhibition attenuated the cell injury. Furthermore, miR-25 negatively controlled the expression of phosphatase and tensin homolog deleted on chromosome 10 (PTEN). Intervention the expression of PTEN using si-PTEN reversed the beneficial effects of miR-25 inhibition on DOX-injured H9c2 cells. Conclusion: In conclusion, this study demonstrated that miR-25 is involved in DOX-induced cell damage through the regulation of PTEN expression.