崔贺贺
中国医学科学院阜外医院 教育处
BACKGROUND:Traditional Chinese medicine Tongxinluo (TXL) has been widely used to treat coronary artery disease in China, since it could reduce myocardial infarct size and ischemia/reperfusion injury in both non-diabetic and diabetic conditions. It has been shown that TXL could regulate peroxisome proliferator activated receptor-α (PPAR-α), a positive modulator of angiopoietin-like 4 (Angptl4), in diabetic rats. Endothelial junction substructure components, such as VE-cadherin, are involved in the protection of reperfusion injury. Thus, we hypothesized cell-intrinsic and endothelial-specific Angptl4 mediated the protection of TXL on endothelial barrier under high glucose condition against ischemia/reperfusion-injury via PPAR-α pathway.METHODS:Incubated with high glucose medium, the human cardiac microvascular endothelial cells (HCMECs) were then exposed to oxygen-glucose-serum deprivation (2 hours) and restoration (2 hours) stimulation, with or without TXL, insulin, or rhAngptl4 pretreatment.RESULTS:TXL, insulin, and rhAngptl4 had similar protective effects on the endothelial barrier. TXL treatment reversed the endothelial barrier breakdown in HCMECs significantly as identified by decreasing endothelial permeability, upregulating the expression of JAM-A, VE-cadherin, and integrin-α5 and increasing the membrane location of VE-cadherin and integrin-α5, and these effects of TXL were as effective as insulin and rhAngptl4. However, Angptl4 knock-down with small interfering RNA (siRNA) interference and PPAR-α inhibitor MK886 partially abrogated these beneficial effects of TXL. Western blotting also revealed that similar with insulin, TXL upregulated the expression of Angptl4 in HCMECs, which could be inhibited by Angptl4 siRNA or MK886 exposure. TXL treatment increased PPAR-α activity, which could be diminished by MK886 but not by Angptl4 siRNA.CONCLUSION:These data suggest cell-intrinsic and endothelial-specific Angptl4 mediates the protection of TXL against endothelial barrier breakdown during oxygen-glucose-serum deprivation and restoration under high glucose condition partly via the PPAR-α/Angptl4 pathway.
Medicine 2020
OBJECTIVE:Endothelial barrier function in the onset and Tongxinluo (TXL) protection of myocardial ischemia/reperfusion (I/R) injury, and TXL can induce the secretion of Angiopoietin-like 4 (Angptl4) in human cardiac microvascular endothelial cells during hypoxia/reoxygenation. We intend to demonstrate whether TXL can attenuate myocardial I/R injury in diabetes, characterized with microvascular endothelial barrier disruption, by induction of Angptl4-mediated protection of endothelial barrier integrity.METHODS AND RESULTS:I/R injury was created by coronary ligation in ZDF diabetic and non-diabetic control rats. The animals were anesthetized and randomized to sham operation or I/R injury with or without the exposure to insulin, rhAngptl4, TXL, Angptl4 siRNA, and the PPAR-α inhibitor MK886. Tongxinluo, insulin and rhAngptl4 have the similar protective effect on diabetic hearts against I/R injury. In I/R-injured diabetic hearts, TXL treatment remarkably reduced the infarct size, and protected endothelial barrier integrity demonstrated by decreased endothelial cells apoptosis, microvascular permeability, and myocardial hemorrhage, fortified tight junction, and upregulated expression of JAM-A, integrin-α5, and VE-cadherin, and these effects of TXL were as effective as insulin and rhAngptl4. However, Angptl4 knock-down with siRNA interference and inhibition of PPAR-α with MK886 partially diminished these beneficial effects of TXL and rhAngptl4. TXL induced the expression of Angptl4 in I/R-injured diabetic hearts, and was canceled by Angptl4 siRNA and MK886. TXL treatment increased myocardial PPAR-α activity, and was abolished by MK886 but not by Angptl4 siRNA.CONCLUSIONS:TXL protects diabetic hearts against I/R injury by activating Angptl4-mediated restoration of endothelial barrier integrity via the PPAR-α pathway.
PloS one 2018
What is the central question of this study? In a rat model of acute myocardial infarction (AMI), we investigated the effect of Tongxinluo (TXL) treatment. Does TXL activate autophagy and attenuate apoptosis of cardiomyocytes through the AMPK pathway to facilitate survival of cardiomyocytes and improve cardiac function? What is the main finding and its importance? Major findings are as follows: (i) TXL treatment preserved cardiac function and reduced ventricular remodelling, infarct size and inflammation in rat hearts after AMI; (ii) TXL treatment dramatically increased autophagy and inhibited apoptosis in myocardium; and (iii) the AMPK signalling pathway played a crucial role in mediating the beneficial effects of TXL. Tongxinluo (TXL) has been demonstrated to have a protective role during ischaemia-reperfusion after acute myocardial infarction, but the long-term effects and underlying mechanisms are still unknown. The aim of this study was to investigate whether TXL could have an effect on apoptosis or autophagy of cardiomyocytes through the AMP-activated protein kinase (AMPK) pathway. Male Sprague-Dawley rats (n = 75) were randomly divided to sham, control, TXL (4 mg kg-1 day-1 orally), compound C (i.p. injection of 10 mg kg-1 day-1 ) and TXL + compound C groups. The extent of fibrosis, infarct size and angiogenesis were determined by pathological and histological studies. Four weeks after acute myocardial infarction, TXL treatment significantly increased ejection fraction, promoted angiogenesis in the peri-infarct region and substantially decreased fibrosis and the size of the infarcted area (P < 0.05). Treatment with TXL also increased AMPK/mTOR phosphorylation, upregulated expression of the autophagic protein LC3 and downregulated expression of the apoptotic protein Bax in the infarcted myocardium (P < 0.05). Addition of the AMPK inhibitor, compound C, counteracted these beneficial effects significantly (P < 0.05). The cardioprotective benefits of TXL against myocardial infarction are related to the inhibition of apoptosis and promotion of autophagy in rat hearts after acute myocardial infarction. This effect may occur through the AMPK signalling pathway.
Experimental physiology 2017
Cardiac microvascular endothelial cells (CMECs) extensively secrete cytokines during myocardial ischemia/reperfusion injury (MIRI). Tongxinluo (TXL) has been demonstrated to preserve the function of the endothelium and myocardium against MIRI. This study was designed to identify alterations in the paracrine function of CMECs under hypoxia/reoxygenation (H/R) conditions and assess its modulation by TXL. CMECs were exposed to different concentrations of TXL for 30 min and then subjected to hypoxia and reoxygenation for 12 and 2 h, respectively. Apoptosis was measured to determine the optimal TXL concentration. Protein antibody arrays were used to assess changes in cytokines secreted into conditioned medium by CMECs. A Gene Ontology (GO) analysis was applied to interpret the functional implications of changes in cytokines. TXL inhibited CMEC apoptosis in a concentration-dependent manner after H/R, reaching peak efficacy at a concentration of 800 μg/ml. H/R significantly altered 33 cytokines, and TXL (800 μg/ml) changed the levels of 121 different cytokines compared with the H/R group. Among these cytokines, 10 that were increased by H/R were decreased by TXL, five that were decreased by H/R were increased by TXL, and eight that were attenuated by H/R were further decreased by TXL. Insulin-like growth factor binding protein-1 was up-regulated by H/R and was further increased by TXL. Significantly altered factors were found to be involved in cell proliferation, growth and differentiation, as well as chemotaxis and transport. TXL inhibited the apoptosis of CMECs and modulated their paracrine function in MIRI.
American journal of translational research 2016
OBJECTIVE:Tongxinluo (TXL) has been shown to decrease myocardial necrosis after ischemia/reperfusion (I/R) by simulating ischemia preconditioning (IPC). However, the core mechanism of TXL remains unclear. This study was designed to investigate the key targets of TXL against I/R injury (IRI) among the cardiac structure-function network.MATERIALS AND METHODS:To evaluate the severity of lethal IRI, a mathematical model was established according to the relationship between myocardial no-reflow size and necrosis size. A total of 168 mini-swine were employed in myocardial I/R experiment. IRI severity among different interventions was compared and IPC and CCB groups were identified as the mildest and severest groups, respectively. Principal component analysis was applied to further determine 9 key targets of IPC in cardioprotection. Then, the key targets of TXL in cardioprotection were confirmed.RESULTS:Necrosis size and no-reflow size fit well with the Sigmoid Emax model. Necrosis reduction space (NRS) positively correlates with I/R injury severity and necrosis size (R2=0.92, R2=0.57, P<0.01, respectively). Functional and structural indices correlate positively with NRS (R2=0.64, R2=0.62, P<0.01, respectively). TXL recovers SUR2, iNOS activity, eNOS activity, VE-cadherin, β-catenin, γ-catenin and P-selectin with a trend toward the sham group. Moreover, TXL increases PKA activity and eNOS expression with a trend away from the sham group. Among the above nine indices, eNOS activity, eNOS, VE-cadherin, β-catenin and γ-catenin expression were significantly up-regulated by TXL compared with IPC (P>0.05) or CCB (P<0.05) and these five microvascular barrier-related indices may be the key targets of TXL in minimizing IRI.CONCLUSIONS:Our study underlines the lethal IRI as one of the causes of myocardial necrosis. Pretreatment with TXL ameliorates myocardial IRI through promoting cardiac microvascular endothelial barrier function by simulating IPC.
PloS one 2015
Tongxinluo (TXL), a traditional Chinese medicine, is widely used to treat cardiovascular diseases in China. Our previous study has demonstrated the pro-survival role of TXL on mesenchymal stem cells (MSCs) in vivo. But whether TXL could decrease apoptosis of MSCs in vitro, and the underlying mechanism are still unknown. Moreover, AMPK/eNOS pathway is crucial in regulating cell apoptosis. Therefore, we designed the study to investigate whether TXL could decrease MSCs apoptosis under hypoxia and serum deprivation (H/SD) conditions and to determine the role of AMPK/eNOS pathway. To test the hypothesis, MSCs were treated with TXL (50-400 μg/mL) under H/SD for 6 hours. For inhibitor studies, the cells were preincubated with AMPK inhibitor compound C. Results indicated that TXL decreased MSCs apoptosis concentration-dependently evidenced by reduced Annexin V+/PI- cells and increased red/green ratio of JC-1. Further, TXL enhanced the phosphorylation of AMPK and eNOS. Whereas, treatment with compound C decreased the phosphorylation of AMPK and eNOS and was accompanied by attenuated anti-apoptotic effect of TXL. In conclusion, TXL protected MSCs against H/SD-induced injury at least in part through the AMPK/eNOS pathway, which provides a novel explanation for the multi-effect of TXL on cardiovascular system.
Journal of cardiovascular pharmacology 2014
: In contrast to cardiomyocytes, autophagy in cardiac microvascular endothelial cells (CMECs) during ischemia/reperfusion (I/R) injury has not been fully investigated. Tongxinluo (TXL), a traditional Chinese medicine, was shown to be vascular protective. We aimed to elucidate the role of autophagy and its regulatory mechanisms by TXL in CMECs subjected to I/R injury. CMECs were exposed to different treatments for 30 minutes and subjected to hypoxia/reoxygenation each for 2 hours. The results indicated that hypoxia/reoxygenation significantly induced autophagy, as identified by an increased number of monodansylcadaverine-positive CMECs, increased autophagosome formation, and a higher type II/type I of light chain 3 ratio, but not Beclin-1 expression. Autophagy inhibition using 3-methyladenine was proapoptotic, but rapamycin-induced autophagy was antiapoptotic. TXL enhanced autophagy and decreased apoptosis in a dose-dependent manner, reaching its largest effect at 800 μg/mL. 3-methyladenine attenuated the TXL-promoted autophagy and antiapoptotic effects, whereas rapamycin had no additional effects compared with TXL alone. TXL upregulated mitogen-activated protein kinase and extracellular signal-regulated kinase (ERK) phosphorylation; however, PD98059 abrogated ERK phosphorylation and decreased autophagy and increased apoptosis compared with TXL alone. These results suggest that autophagy is a protective mechanism in CMECs subjected to I/R injury and that TXL can promote autophagy through activation of the mitogen-activated protein kinase/ERK pathway.
Journal of cardiovascular pharmacology 2014
OBJECTIVE:Myocardial edema plays an important role in the development of myocardial no-reflow and reperfusion injury after the revascularization of acute myocardial infarction (AMI). The present study investigated whether the effect of ischemic preconditioning (IPC) against myocardial no-reflow and reperfusion injury was related to the reduction of myocardial edema through the protein kinase A (PKA) pathway.METHODS:Twenty-four minipigs were randomized into sham, AMI, IPC, and IPC + H-89 (PKA inhibitor, 1.0 µg · kg(-1) · min(-1)) groups. The area of no-reflow (ANR), area of necrosis (AN), and water content in left ventricle and ischemic-myocardium and non-ischemic area were determined by pathological studies. Microvascular permeability was determined by FITC-labeled dextran staining. Cardiomyocyte cross-sectional area (CSA) and mitochondria cross-sectional area (MSA) were evaluated by histological analysis. Myocardial expression of aquaporins (AQPs) was detected by Western blot.RESULTS:Compared with the MI group, the sizes of no-reflow and infarct were reduced by 31.9% and 46.6% in the IPC group (all P < 0.01), water content was decreased by 5.7% and 4.6% in the reflow and no-reflow myocardium of the IPC group (all P < 0.05), microvascular permeability and cardiomyocytes swelling in the reflow area were inhibited by 29.8% and 21.3% in the IPC group (all P < 0.01), mitochondrial water accumulation in the reflow and no-reflow areas of the IPC group were suppressed by 45.5% and 34.8% respectively (all P < 0.01), and the expression of aquaporin-4, -8, and -9 in the reflow and no-reflow myocardium were blocked in the IPC group. However, these beneficial effects of IPC were partially abolished in the IPC + H-89 group.CONCLUSIONS:The cardioprotective effects of IPC against no-reflow and reperfusion injury is partly related to the reduction of myocardial edema by inhibition of microvascular permeability and aquaporins up-regulation via PKA pathway.
Zhonghua xin xue guan bing za zhi 2012
