Circ_0090231 knockdown protects vascular smooth muscle cells from ox-LDL-induced proliferation, migration and invasion via miR-942-5p/PPM1B axis during atherosclerosis.

Atherosclerosis (AS) is a dominant pathological basis of cardiovascular disease. Circular RNAs (circRNAs) have been proposed to have crucial functions in regulating pathological progressions of AS. Hence, the aim of this study was to investigate the potential function of circ_0090231 in AS progression. Oxidized low densitylipoprotein (ox-LDL)-challenged vascular smooth muscle cells (VSMCs) were used for in vitro functional analysis. Levels of genes and proteins were measured by qRT-PCR and Western blot. The proliferation, migration and invasion were assessed using cell counting kit-8, 5-ethynyl-2'-deoxyuridine, and transwell assays. The interaction between miR-942-5p and circ_0090231 or PPM1B (Protein Phosphatase, Mg2+/Mn2+ Dependent 1B) was evaluated by dual-luciferase reporter and pull-down assays. Circ_0090231 is a stable circRNA, and was increased in the serum of AS patients and ox-LDL-challenged VSMCs. Functionally, silencing of circ_0090231 could reverse ox-LDL-induced proliferation, migration and invasion in VSMCs. Mechanistically, circ_0090231 directly targeted miR-942-5p, and PPM1B was a target of miR-942-5p. Besides, circ_0090231 sequestered miR-942-5p to release PPM1B expression, suggesting the circ_0090231/miR-942-5p/PPM1B axis. Further rescue experiments showed that miR-942-5p inhibition or ectopic overexpression of PPM1B dramatically attenuated the suppressing influences of circ_0090231 knockdown on VSMC proliferative, migratory and invasive abilities under ox-LDL treatment. Silencing of circ_0090231 could reverse ox-LDL-induced proliferation, migration and invasion in VSMCs via miR-942-5p/PPM1B axis, providing a theoretical basis for elucidating the mechanism of AS process.

[Chikusetsu saponin â £a ameliorates myocardial hypertrophy of rats through regulating expression of miR199a-5p/Atg5].

The present study investigated the effects of chikusetsu saponin Ⅳa(CHS Ⅳa) on isoproterenol(ISO)-induced myocardial hypertrophy in rats and explored the underlying molecular mechanism. ISO was applied to establish a rat model of myocardial hypertrophy, and CHS Ⅳa(5 and 15 mg·kg~(-1)·d~(-1)) was used for intervention. The tail artery blood pressure was measured. Cardiac ultrasound examination was performed. The ratio of heart weight to body weight(HW/BW) was calculated. Morphological changes in the myocardial tissue were observed by HE staining. Collagen deposition in the myocardial tissue was observed by Masson staining. The mRNA expression of myocardial hypertrophy indicators(ANP and BNP), autophagy-related genes(Atg5, P62 and beclin1), and miR199 a-5 p was detected by qRT-PCR. Atg5 protein expression was detected by Western blot. The results showed that the model group exhibited increased tail artery blood pressure and HW/BW ratio, thickened left ventricular myocardium, enlarged myocardial cells, disordered myocardial fibers with widened interstitium, and a large amount of collagen aggregating around the extracellular matrix and blood vessels. ANP and BNP were largely expressed. Moreover, P62 expression was up-regulated, while beclin1 expression was down-regulated. After intervention by CHS Ⅳa at different doses, myocardial hypertrophy was ameliorated and autophagy activity in the myocardial tissue was enhanced. Meanwhile, miR199 a-5 p expression declined and Atg5 expression increased. As predicted by bioinformatics, Atg5 was a target gene of miR199 a-5 p. CHS Ⅳa was capable of preventing myocardial hypertrophy by regulating autophagy of myocardial cells through the miR-199 a-5 p/Atg5 signaling pathway.

Chikusetsu saponin IVa attenuates isoprenaline-induced myocardial fibrosis in mice through activation autophagy mediated by AMPK/mTOR/ULK1 signaling.

BACKGROUND: Myocardial fibrosis is a common pathological manifestation of many cardiovascular diseases at the end stage. Autophagy has been demonstrated to play a protective role in the cardiac fibrosis. Our previous studies have demonstrated that the Saponins from Panax japonicus effectively ameliorated the degree of fibrosis in rat acute myocardial ischemia injury model though the mechanisms are not clear. HYPOTHESIS: We hypothesized that Chikusetsusaponin IVa (CS), a major component of Saponins from Panaxjaponicus, may improve isoprenaline induced myocardial fibrosis via AMPK/mTOR/ULK1 mediated autophagy METHODS: Continuous subcutaneous injection of isoproterenol for 21 days was used to induce myocardial fibrosis in mice and high and low doses (15 mg/kg and 5 mg/kg) of CS was administered by oral gavage to observe the efficacy. Animals were sacrificed 12 h after the last administration and samples were collected. H&E staining, Masson staining and wheat germ agglutinin (WGA) staining were used to evaluate histopathological changes, collagen deposition and myocardial cell hypertrophy. Autophagy-related markers (LC3ß, Beclin1 and p62) and AMPK/mTOR/ULK1 pathway-related markers were evaluated by western blot. RESULTS: CS effectively attenuated isoprenaline-induced myocardial fibrosis in vivo, reduced the heart index, inhibited inflammatory infiltration, decreased collagen deposition and myocardial cell size. CS treatment rescued the expression of autophagy-related markers. CS activated autophagy through the activation of AMPK, which in turn inhibited the phosphorylation of mTOR and ULK1(Ser757), rather than directly phosphorylate ULK1(Ser555) by AMPK. CONCLUSION: Our data demonstrated that CS attenuated isoprenaline-induced myocardial fibrosis by activating autophagy through AMPK/mTOR/ULK1 pathway. Our findings suggested that CS is a potential candidate drug against cardiac fibrosis and have identified potential drug targets for the treatment of heart diseases.

[Expression and bioinformatics analysis of miRNA in ISO-induced rat cardiac hypertrophy].

OBJECTIVE: To investigate the expression changes of miRNAs (miR199a-5P, miR206, miR133a-3P, miR499-5P) in rat model of cardiac hypertrophy induced by isoproterenol (ISO), and to explore the main signal pathways and molecular mechanisms which related to that with the way of bioinformatics. METHODS: Sixteen SD male rats were randomly divided into two groups: control group and ISO model group. The rats in model group were treated with ISO (1 mg/kg) to induce cardiac hypertrophy, the rats in control group were treated with the same amount of saline, and all were injected subcutaneously at the back. After 10 days of continuous administration, interventricular septal thickness at diastole (IVSd), left ventricular posterior wall thickness at diastole (LVPWd) , left ventricular end-diastolic diameter(LVDd), and systolic function (EF%) were measured by echocardiography. Heart weight (HW) and rat body weight (BW) were weighed, and heart/body weight ratio (HW/BW) was calculated. Myocardial tissues were stained with HE, and myocardial cell surface area was measured by Image J analysis software; RT-qPCR was used to detect the expressions of 4 miRNAs in rat myocardial tissues. Targetscan, miRDB and miRwalk databases were used to predict the possible target genes of four kinds of miRNAs in rats, and FunRich software was used to analyze and predict the signal pathways related to the target genes. RESULTS: Compared with the control group, the IVSd and LVPWd in the model group were thickened, the LV was increased, and the EF% was decreased significantly. The HW and HW/BW were increased. The myocardial cell volume in the model group was increased significantly, the arrangement was disordered, and the cell surface area was increased; the expressions of miR199a-5P and miR206 in the model group were up-regulated by RT-qPCR (P＜0.05); the expressions of miR133a-3P and miR499-5P were down-regulated (P＜0.05). Predicted by bioinformatics application, related signal pathways which target genes of 4 miRNAs maybe involved in cardiac hypertrophy mainly are: VEGF/VEGFR signal pathway, ErbB receptor signal pathway and other signal pathways. CONCLUSION: ISO-induced cardiac hypertrophy leads to changes in miRNA expression, and bioinformatics predicts related target genes of four miRNAs involved in cardiac hypertrophy and their major signaling pathways. These studies will provide new ideas for the regulation of cardiac hypertrophy and its prevention and treatment measures.