scholarly journals Cannabinoid receptor 2 deletion deteriorates myocardial infarction through the down-regulation of AMPK-mTOR-p70S6K signaling-mediated autophagy

2019 ◽  
Vol 39 (4) ◽  
Author(s):  
Yao Hu ◽  
Yu Tao ◽  
Jing Hu

AbstractCannabinoid receptor 2 (CB2R) has been reported to play an important role in the regulation of pathogenesis and progression of myocardial infarction (MI). Here we tried to investigate its potential mechanisms. The ratio of infarct size in heart issue was detected by TTC staining, and cardiac functions were calculated according to echocardiographic evaluation. Cell viability in cardiomyocytes was investigated by Cell Counting Kit-8 (CCK-8) and lactate dehydrogenase (LDH) release assays. Western blot was used to detect autophagy-related proteins including Beclin-1, LC3, p62, adenosine 5′-monophosphate (AMP)-activated protein kinase (AMPK)-mammalian target of rapamycin rabbit (mTOR)-p70 ribosomal protein S6 kinase (p70S6K) signaling-related proteins including AMPK, mTOR, p70S6K, and their phosphorylation formation. Rapamycin was used for the induction of autophagy. Cleaved caspase-3 and Bax were detected for analyzing apoptosis. TEM was used for the detection of autophagosomes. We found that CB2R deletion (CB2R KO) largely deteriorated the severity of MI and the cardiac function as well as cell viability of cardiomyocytes. Knocking out CB2R decreased the level of autophagy in heart issues from MI mice as well as cardiomyocytes under oxygen-glucose deprivation (OGD). Furthermore, CB2R dysfunction significantly attenuated the cardiac protective effects of rapamycin both in vivo and in vitro. Finally, we found that CB2R-mediated autophagy was induced by AMPK-mTOR-p70S6K signaling pathway. Our current study demonstrated for the first time that CB2R deletion led to a detrimental effect of MI through the dysfunction of AMPK-mTOR-p70S6K signaling pathway, which might provide a novel insight in the treatment of MI.

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Guo Zu ◽  
Jing Guo ◽  
Ningwei Che ◽  
Tingting Zhou ◽  
Xiangwen Zhang

Abstract Ginsenoside Rg1 (Rg1) is one of the major bioactive ingredients in Panax ginseng, and it attenuates inflammation and apoptosis. The aims of our study were to explore the potential of Rg1 for the treatment of intestinal I/R injury and to determine whether the protective effects of Rg1 were exerted through the Wnt/β-catenin signaling pathway. In this study, Rg1 treatment ameliorated inflammatory factors, ROS and apoptosis that were induced by intestinal I/R injury. Cell viability was increased and cell apoptosis was decreased with Rg1 pretreatment following hypoxia/reoxygenation (H/R) in the in vitro study. Rg1 activated the Wnt/β-catenin signaling pathway in both the in vivo and in vitro models, and in the in vitro study, the activation was blocked by DKK1. Our study provides evidence that pretreatment with Rg1 significantly reduces ROS and apoptosis induced by intestinal I/R injury via activation of the Wnt/β-catenin pathway. Taken together, our results suggest that Rg1 could exert its therapeutic effects on intestinal I/R injury through the Wnt/β-catenin signaling pathway and provide a novel treatment modality for intestinal I/R injury.


2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Kaifeng Li ◽  
Mengen Zhai ◽  
Liqing Jiang ◽  
Fan Song ◽  
Bin Zhang ◽  
...  

Hyperglycemia-induced oxidative stress and fibrosis play a crucial role in the development of diabetic cardiomyopathy (DCM). Tetrahydrocurcumin (THC), a major bioactive metabolite of natural antioxidant curcumin, is reported to exert even more effective antioxidative and superior antifibrotic properties as well as anti-inflammatory and antidiabetic abilities. This study was designed to investigate the potential protective effects of THC on experimental DCM and its underlying mechanisms, pointing to the role of high glucose-induced oxidative stress and interrelated fibrosis. In STZ-induced diabetic mice, oral administration of THC (120 mg/kg/d) for 12 weeks significantly improved the cardiac function and ameliorated myocardial fibrosis and cardiac hypertrophy, accompanied by reduced reactive oxygen species (ROS) generation. Mechanically, THC administration remarkably increased the expression of the SIRT1 signaling pathway both in vitro and in vivo, further evidenced by decreased downstream molecule Ac-SOD2 and enhanced deacetylated production SOD2, which finally strengthened antioxidative stress capacity proven by repaired activities of SOD and GSH-Px and reduced MDA production. Additionally, THC treatment accomplished its antifibrotic effect by depressing the ROS-induced TGFβ1/Smad3 signaling pathway followed by reduced expression of cardiac fibrotic markers α-SMA, collagen I, and collagen III. Collectively, these finds demonstrated the therapeutic potential of THC treatment to alleviate DCM mainly by attenuating hyperglycemia-induced oxidative stress and fibrosis via activating the SIRT1 pathway.


2020 ◽  
Vol 11 (5) ◽  
Author(s):  
Yi Peng ◽  
Ji-Ling Zhao ◽  
Zhi-Yong Peng ◽  
Wei-Fang Xu ◽  
Guo-Long Yu

Abstract Mesenchymal stem cell (MSC) therapy is a promising approach against myocardial infarction (MI). Studies have demonstrated that MSCs can communicate with other cells by secreting exosomes. In the present study, we aimed to identify exosomal microRNAs that might contribute to MSC-mediated cardioprotective effects. Primary cardiomyocytes were deprived of oxygen and glucose to mimic MI in vitro. For the animal model of MI, the left anterior descending artery was ligated for 1 h, followed by reperfusion for 12 h. MSC-derived exosomes were used to treat primary cardiomyocytes or mice. Cardioprotection-related microRNAs were determined, followed by target gene identification and functional studies with quantitative PCR, western blotting, MTT assay, flow cytometry assay, chromatin immunoprecipitation and dual-luciferase assay. We found that MSC co-culture reduced OGD-induced cardiomyocyte apoptosis and inflammatory responses. Cardioprotection was also observed upon treatment with MSC-derived exosomes in vitro and in vivo. In line with this, exosome uptake led to a significant increase in miR-25-3p in cardiomyocytes. Depletion of miR-25-3p in MSCs abolished the protective effects of exosomes. Mechanistically, miR-25-3p directly targeted the pro-apoptotic genes FASL and PTEN and reduced their protein levels. Moreover, miR-25-3p decreased the levels of EZH2 and H3K27me3, leading to derepression of the cardioprotective gene eNOS as well as the anti-inflammatory gene SOCS3. Inhibition of EZH2 or overexpression of miR-25-3p in cardiomyocytes was sufficient to confer cardioprotective effects in vitro and in vivo. We concluded that exosomal miR-25-3p from MSCs alleviated MI by targeting pro-apoptotic proteins and EZH2.


2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Xing Li ◽  
Dan Luo ◽  
Yu Hou ◽  
Yonghui Hou ◽  
Shudong Chen ◽  
...  

Spinal cord microcirculation involves functioning endothelial cells at the blood spinal cord barrier (BSCB) and maintains normal functioning of spinal cord neurons, axons, and glial cells. Protection of both the function and integrity of endothelial cells as well as the prevention of BSCB disruption may be a strong strategy for the treatment of spinal cord injury (SCI) cases. Sodium Tanshinone IIA silate (STS) is used for the treatment of coronary heart disease and improves microcirculation. Whether STS exhibits protective effects for SCI microcirculation is not yet clear. The purpose of this study is to investigate the protective effects of STS on oxygen-glucose deprivation- (OGD-) induced injury of spinal cord endothelial cells (SCMECs) in vitro and to explore effects on BSCB and neurovascular protection in vivo. SCMECs were treated with various concentrations of STS (1 μM, 3 μM, and 10 μM) for 24 h with or without OGD-induction. Cell viability, tube formation, migration, and expression of Notch signaling pathway components were evaluated. Histopathological evaluation (H&E), Nissl staining, BSCB permeability, and the expression levels of von Willebrand Factor (vWF), CD31, NeuN, and Notch signaling pathway components were analyzed. STS was found to improve SCMEC functions and reduce inflammatory mediators after OGD. STS also relieved histopathological damage, increased zonula occludens-1 (ZO-1), inhibited BSCB permeability, rescued microvessels, protected motor neuromas, and improved functional recovery in a SCI model. Moreover, we uncovered that the Notch signaling pathway plays an important role during these processes. These results indicated that STS protects microcirculation in SCI, which may be used as a therapeutic strategy for SCI in the future.


ACS Omega ◽  
2020 ◽  
Vol 5 (22) ◽  
pp. 13096-13107
Author(s):  
Chie Moritani ◽  
Kayoko Kawakami ◽  
Hiroshi Shimoda ◽  
Tadashi Hatanaka ◽  
Etsuko Suzaki ◽  
...  

2017 ◽  
Vol 35 (15_suppl) ◽  
pp. e23102-e23102
Author(s):  
Nicola Maurea ◽  
Carmela Coppola ◽  
Giovanna Piscopo ◽  
Gennaro Riccio ◽  
Domenica Rea ◽  
...  

e23102 Background: Ado trastuzumab emtansine (TDM1) is a novel antibody–drug conjugate consisting of trastuzumab (TRAS) covalently linked to the highly potent microtubule inhibitory agent DM1 via a stable thioether linker. TDM1 is used in metastatic ErbB2 positive breast cancer patients. Although, the potential cardiotoxic effects of TDM1 have not yet been fully elucidated, they can include changes in Ca2+ regulation related to blockade of ErbB2, PI3K-Akt and MAPK pathways. Here, we aim to elucidate whether Ranolazine (R), administered after TDM1 treatment, blunts or not cardiotoxicity in vivo and in vitro. Methods: In vitro, human fetal cardiomyocytes (HFC) were treated with TDM1 for 3 days and then treated in the absence or presence of R for 3 days. Cell viability was assessed by cell counting and MTT assay. To evaluate cardiac function in vivo, C57/BL6 mice, 2-4 months old, were daily treated with TDM1 (44.4 mg/kg/day). At day 0 and after 7 days, fractional shortening (FS) and ejection fraction (EF) were measured, by M/B mode echocardiography, and radial and longitudinal strain (RS and LS) were evaluated using 2D speckle-stracking. These measurements were repeated after 5 days of R treatment (305 mg/Kg/day), started at the end of TDM1 treatment. Results: R reduces TDM1 toxicity in HFC, as evidenced by the higher percentage of viable cells treated with TDM1+ R with respect to the cells treated with TDM1 alone (p < 0.01). In in vivo studies: after 7 days with TDM1 administration, FS decreased to 53.6±0.9%, versus 61.0±0.8 % (sham), (p < 0.01), and EF decreased to 85.5±3.5 % versus 91.0±0.8% (sham), (p < 0.01). Moreover, RS decreased to 20.92±3.2 % versus 42.2±10.1% (sham) (p < 0.01), and LS decreased to -15.5±2.8 % versus -23.6±6.7% (sham), (p < 0.01).In mice treated with TDM1 and, successively treated with R for 5 days, the indices of cardiac function partially recovered: FS 58±2.4 % (p < 0.05), EF 88.8±1.7 %, (p < 0.05), RS (35.7±8.2 %, p > 0.05), whereas the alteration of LS persists even after treatment with R (-17.3±3.7 %, p > 0.05) Conclusions: Here we show that in vivo R post-treatment reduces cardiotoxic effects due to TDM1, as demonstrated by the recovery of FS, EF and RS values. As expected, R increases cell viability of HFC treated with TDM1.


2009 ◽  
Vol 297 (4) ◽  
pp. C928-C934 ◽  
Author(s):  
Changgong Wu ◽  
Lin Yan ◽  
Christophe Depre ◽  
Sunil K. Dhar ◽  
You-Tang Shen ◽  
...  

Cytochrome c oxidase (COX) is composed of 13 subunits, of which COX I, II, and III are encoded by a mitochondrial gene. COX I and II function as the main catalytic components, but the function of COX III is unclear. Because myocardial ischemia affects mitochondrial oxidative metabolism, we hypothesized that COX activity and expression would be affected during postischemic cardiomyopathy. This hypothesis was tested in a monkey model following myocardial infarction (MI) and subsequent pacing-induced heart failure (HF). In this model, COX I protein expression was decreased threefold after MI and fourfold after HF ( P < 0.05 vs. sham), whereas COX II expression remained unchanged. COX III protein expression increased 5-fold after MI and further increased 10-fold after HF compared with sham ( P < 0.05 vs. sham). The physiological impact of COX III regulation was examined in vitro. Overexpression of COX III in mitochondria of HL-1 cells resulted in an 80% decrease in COX I, 60% decrease in global COX activity, 60% decrease in cell viability, and threefold increase in apoptosis ( P < 0.05). Oxidative stress induced by H2O2 significantly ( P < 0.05) increased COX III expression. H2O2 decreased cell viability by 47 ± 3% upon overexpression of COX III, but only by 12 ± 5% in control conditions ( P < 0.05). We conclude that ischemic stress in vivo and oxidative stress in vitro lead to upregulation of COX III, followed by downregulation of COX I expression, impaired COX oxidative activity, and increased apoptosis. Therefore, upregulation of COX III may contribute to the increased susceptibility to apoptosis following MI and subsequent HF.


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