miR-148a-3p improves mitochondrial injury and apoptosis induced by high-glucose through inhibiting CRT expression / 西安交通大学学报(医学版)

【Objective】 To evaluate the effects of miR-148a-3p on calreticulin (CRT) expression and mitochondrial function in cardiomyocytes incubated with high glucose. 【Methods】 miR-148a-3p minic and inhibitor were used to intervene the H9c2 cardiomyocytes of rats. The expression of CRT protein was detected. Then the cells were divided into control group, high-glucose group (HG), HG +miR-148a-3p minic group, HG + miR-148a-3p minic + TG (CRT agonist) group, HG + miR-148a-3p inhibitor group, and HG + miR-148a-3p inhibitor + CRT- (CRT-siRNA) group. The content of adenosine triphosphate (ATP) and the level of reactive oxygen species (ROS), the activity of mitochondrial respiratory chain complex enzyme and apoptotic rate were detected. 【Results】 miR-148a-3p minic significantly inhibited the expression of CRT protein in cardiomyocytes, while miR-148a inhibitor increased the expression of CRT. miR-148a-3p minic inhibited the decrease of ATP production, the increase of ROS production and cell apoptosis, and the inactivity of mitochondrial respiratory chain complex enzyme in cardiomyocytes induced by high glucose, while TG weakened the above effects of miR-148a-3p minic. miR-148a inhibitor aggravated the mitochondrial injury and apoptosis of cardiomyocytes induced by high glucose, but the effects of miR-148a-3p inhibitor were partially blocked by CRT-siRNA. 【Conclusion】 miR-148a-3p negatively regulates the expression of CRT in cardiomyocytes and protects the mitochondrial injury and apoptosis induced by high-glucose through inhibiting CRT.

Analysis of circRNA expression profile and functional enrichment of myocardial mitochondria in mice with diabetic cardiomyopathy / 西安交通大学学报(医学版)

【Objective】 To explore the differential expression and functional analysis of circRNA from myocardial mitochondria in diabetes cardiomyopathy (DCM) mice. 【Methods】 The DCM mice model was established in 16-week-old db/db mice, and C57BL/KsJ mice were used as controls. RNA was extracted from the myocardium of two groups of mice, high-throughput sequencing was used to screen mitochondrial circRNA differentially expressed in the two groups, RT-qPCR was used to verify the sequencing results of the first 10 circRNAs with significant differential expression, and functional enrichment analysis was performed on the differentially expressed circRNA target genes, and miRNA target prediction software was used to analyze the circRNA-miRNA co-expression network. 【Results】 There were 147 mitochondrial circRNAs differentially expressed in the myocardium of DCM mice, including 89 highly expressed and 58 low expressed. The expression pattern of differentially expressed circRNAs in tissues was consistent with those of sequencing results. The enrichment analysis of GO and KEGG showed that the differentially expressed circRNA target genes were mainly enriched in cGMP/PKG, glucagon pathways, which were related to mitochondrial energy metabolism and cardiac hypertrophy. circRNA-miRNA co-expression analysis found that the most significantly up-regulated circRNA, chrM:1207-1536+, was associated with miR-491-3p, miR-99a-3p, and miR-99b-3p, and the most significantly down-regulated circRNA, chrM:1453-3205+, was associated with miR-181b-1-3p, miR-181b-2-3p, and miR-672-5p. 【Conclusion】 Compared to the control mice, there is differential expression of circRNAs in myocardial mitochondria of DCM mice. The differentially expressed circRNAs may interact with the corresponding miRNA to affect myocardial fibrosis and hypertrophy through regulation of energy metabolism, apoptosis and other pathways, thus participating in the pathogenesis of DCM.

Rosmarinic acid inhibits high glucose-induced cardiomyocyte hypertrophy by activating Parkin-mediated mitophagy / 南方医科大学学报

OBJECTIVE@#To evaluate the effect of rosmarinic acid (RA) on mitophagy and hypertrophy of cardiomyocytes exposed to high glucose (HG).@*METHODS@#Rat cardiomyocytes (H9c2) exposed to HG (25 mmol/L) were treated with 50 μmol/L RA or with both RA treatment and Parkin siRNA transfection, with the cells cultured in normal glucose (5.5 mmol/L) and HG as the controls. The expressions of PINK1, Parkin and LC3II/LC3I in the cells were detected by Western blotting. The formation of mitochondrial autophagosomes was observed by transmission electron microscope. Flow cytometry was employed to detect the level of reactive oxygen species (ROS) and apoptotic rate of the cells. The activities of respiratory chain complex enzymes were measured by spectrophotometry. Fluorescence enzyme labeling and @*RESULTS@#RA treatment significantly increased the expression levels of PINK1, Parkin and LC3-II/I (@*CONCLUSIONS@#RA can protect rat cardiomyocytes against oxidative stress injury and cardiomyocyte hypertrophy induced by HG by activating Parkin-mediated mitophagy.

Changes of cardiac structure and AngⅡ in streptozotocin-induced diabetic cardiomyopathy rats / 西安交通大学学报(医学版)

Objective To explore the changes of cardiac structure and function in streptozotocin (STZ)-induced diabetic cardiomyopathy (DCM)rats so as to detect the level of angiotensinⅡ (AngⅡ)in blood and the myocardium and illuminate the role of AngⅡ in DCM.Methods We randomly divided 30 SD rats into control group and DCM group (which received a single injection of streptozotocin,65 mg/kg).The changes of cardiac structure and function were observed by ultrasonic cardiogram at the end of 16 weeks after injection.Then the changes in the myocardium were also analyzed by using hemotoxylin and eosin staining and Sirius red staining.The level of AngⅡ in blood was tested by radioimmunoassay.The expression of AngⅡ in the myocardium was detected by immunofluorescence. Results Compared with those of the controls,the hearts were dilated in DCM rats accompanied with cardiac dysfunction.There were significant increases in LVEDd,LVESd,LVEDv,and LVESv but decrease in LVEF (P <0.05).There were arrangement disorder and hypertrophic cardiomyocytes in DCM.Then the fibrosis area of DCM was significantly increased compared with that of the controls.The level of AngⅡ in blood and myocardium was significantly higher in DCM than in controls.At the same time,Pearson analysis revealed that the level of AngⅡ in blood was positively related to the collagen content of myocardium (r =0.907,P <0.05).Conclusion Our study provides experimental evidence that AngⅡ plays an important role in myocardial fibrosis of DCM.

Role of calreticulin-induced mitochondrial damage in high glucose-in-duced apoptosis of myocardial cells / 中国病理生理杂志

[ ABSTRACT] AIM:To observe the effect of high glucose on the protein expression of calreticulin ( CRT) and its association with cell apoptosis and mitochondrial dysfunction in the cardiomyocytes.METHODS: AC-16 cardiomyocytes were randomly divided into normal glucose group, high glucose group, high glucose+CRT siRNA group and isotonic con-trol group.The cell apoptotic rate, reactive oxygen species (ROS), mitochondrial membrane potential level, respiratory enzyme activity, and protein expression of CRT were observed.RESULTS: Compared with the cardiomyocytes in normal glucose group, the apoptotic rate and ROS production of cardiomyocytes increased in high glucose group, accompanying with the decreases in the mitochondrial membrane potential level and enzyme activitiy of the respiratory chain.The protein expression of CRT was significantly increased in high glucose group.However, compared with high glucose group, high glucose+CRT siRNA decreased the expression of CRT and attenuated the damage of mitochondria, but CRT siRNA did not reduce the ROS level in cardiomyocytes.CONCLUSION:High glucose brings about CRT over-expression to induce mito-chondrial injury, thus increasing myocardial apoptosis.