Medicine and Health Sciences Commons^™

Extracellular Vesicle-Derived Mir-144 As A Novel Mechanism For Chronic Intermittent Hypoxia-Induced Endothelial Dysfunction, Huina Zhang, Lu Peng, Yifan Wang, Wen Zhao, Wayne Bond Lau, Yajing Wang, Yu Li, Yunhui Du, Linyi Li, Yu Huang, Shaoping Nie, Yanwen Qin, Xinliang Ma, Yongxiang Wei

Department of Emergency Medicine Faculty Papers

Rationale: Extracellular vesicles (EVs) play a significant role in cell-cell communication. However, whether and how extracellular vesicles are involved in chronic intermittent hypoxia-induced endothelial dysfunction is unknown. Methods: Comparative transcriptomics analysis and miRNA screening were used to identify the possible pathways or target molecules mediating chronic intermittent hypoxia-induced endothelial function. Serum- or erythrocyte-derived EVs were isolated through ultracentrifugation plus filtration. After in vitro or in vivo treatment with EVs, aortic rings were treated with dihydroethidium staining for superoxidative anion measurement or mounted with wire myography to measure isometric forces. Immunoblotting and qPCR were used for evaluating the molecular mechanism mediating …

C1q/Tnf-Related Protein 5 Contributes To Diabetic Vascular Endothelium Dysfunction Through Promoting Nox-1 Signaling., Jing Liu, Zhijun Meng, Lu Gan, Rui Guo, Jia Gao, Caihong Liu, Di Zhu, Demin Liu, Ling Zhang, Zhen Zhang, Dina Xie, Xiangying Jiao, Wayne Bond Lau, Bernard L. Lopez, Theodore A. Christopher, Xin-Liang Ma, Jimin Cao, Yajing Wang

Department of Emergency Medicine Faculty Papers

OBJECTIVE: Dysregulated adipokine profiles contribute to the pathogenesis of diabetic cardiovascular complications. Endothelial cell (EC) dysfunction, a common pathological alteration in cardiovascular disorders, is exaggerated in diabetes. However, it is unclear whether and how dysregulated adipokines may contribute to diabetic EC dysfunction.

METHODS AND RESULTS: Serum C1q/TNF-Related Protein 5 (CTRP5) were determined in control/diabetes patients, and control/diabetic mice (high-fat diet, HFD). We observed for the first time that serum total CTRP5 was increased, high molecular weight (HMW) form was decreased, but the globular form (gCTRP5) was significantly increased in diabetic patients. These pathological alterations were reproduced in diabetic mice. To …

Adiporon, The First Orally Active Adiponectin Receptor Activator, Attenuates Postischemic Myocardial Apoptosis Through Both Ampk-Mediated And Ampk-Independent Signalings., Yanqing Zhang, Jianli Zhao, Rui Li, Wayne Bond Lau, Yue-Xing Yuan, Bin Liang, Rong Li, Er-He Gao, Walter J. Koch, Xin-Liang Ma, Ya-Jing Wang

Department of Emergency Medicine Faculty Papers

Adiponectin (APN) is a cardioprotective molecule. Its reduction in diabetes exacerbates myocardial ischemia/reperfusion (MI/R) injury. Although APN administration in animals attenuates MI/R injury, multiple factors limit its clinical application. The current study investigated whether AdipoRon, the first orally active molecule that binds APN receptors, may protect the heart against MI/R injury, and if so, to delineate the involved mechanisms. Wild-type (WT), APN knockout (APN-KO), and cardiomyocyte specific-AMPK dominant negative (AMPK-DN) mice were treated with vehicle or AdipoRon (50 mg/kg, 10 min prior to MI) and subjected to MI/R (30 min/3-24 h). Compared with vehicle, oral administration of AdipoRon to WT …

Irf8 Suppresses Pathological Cardiac Remodelling By Inhibiting Calcineurin Signalling., Ding-Sheng Jiang, Xiang Wei, Xiao-Fei Zhang, Yu Liu, Yan Zhang, Ke Chen, Lu Gao, Heng Zhou, Xue-Hai Zhu, Peter P. Liu, Wayne Bond Lau, Xin-Liang Ma, Yunzeng Zou, Xiao-Dong Zhang, Guo-Chang Fan, Hongliang Li

Department of Emergency Medicine Faculty Papers

Interferon regulatory factor 8 (IRF8) is known to affect the innate immune response, for example, by regulating the differentiation and function of immune cells. However, whether IRF8 can influence cardiac hypertrophy is unknown. Here we show that IRF8 levels are decreased in human dilated/hypertrophic cardiomyopathic hearts and in murine hypertrophic hearts. Mice overexpressing Irf8 specifically in the heart are resistant to aortic banding (AB)-induced cardiac hypertrophy, whereas mice lacking IRF8 either globally or specifically in cardiomyocytes develop an aggravated phenotype induced by pressure overload. Mechanistically, we show that IRF8 directly interacts with NFATc1 to prevent NFATc1 translocation and thus inhibits …

Adiponectin Inhibits Oxidative/Nitrative Stress During Myocardial Ischemia And Reperfusion Via Pka Signaling., Yanqing Zhang, Xiao-Liang Wang, Jianli Zhao, Ya-Jing Wang, Wayne Bond Lau, Yue-Xing Yuan, Er-He Gao, Walter J. Koch, Xin-Liang Ma

Department of Emergency Medicine Faculty Papers

The cardioprotective effects of adiponectin (APN) against myocardial ischemia/reperfusion (MI/R) injury are well known. However, comprehension of the mechanisms mediating intracellular APN signaling remains incomplete. We recently demonstrate the antioxidant/antinitrative effects of APN are not dependent on AMPK. Protein kinase A (PKA) has been previously shown to be activated by APN, with uncertain relevance to APN cardiac protection. The current study determined whether the antioxidative/antinitrative effect of APN is mediated by PKA. Administration of APN (2 μg/g) 10 min before reperfusion significantly enhanced cardiac PKA activity, reduced oxidative stress, and decreased infarct size. Knockdown of cardiac PKA expression (PKA-KD) by …

Lymphotoxin-Α Is A Novel Adiponectin Expression Suppressor Following Myocardial Ischemia/Reperfusion., Wayne Bond Lau, Yanqing Zhang, Jianli Zhao, Baojiang Liu, Xiaoliang Wang, Yuexing Yuan, Theodore A. Christopher, Bernard Lopez, Erhe Gao, Walter J. Koch, Xin L. Ma, Yajing Wang

Department of Emergency Medicine Faculty Papers

Recent clinical observations demonstrate adiponectin (APN), an adipocytokine with potent cardioprotective actions, is significantly reduced following myocardial ischemia/reperfusion (MI/R). However, mechanisms responsible for MI/R-induced hypoadiponectinemia remain incompletely understood. Adult male mice were subjected to 30-min MI followed by varying reperfusion periods. Adipocyte APN mRNA and protein expression and plasma APN and TNFα concentrations were determined. APN expression/production began to decline 3 h after reperfusion (reaching nadir 12 h after reperfusion), returning to control levels 7 days after reperfusion. Plasma TNFα levels began to increase 1 h after reperfusion, peaking at 3 h and returning to control levels 24 h after …

The Alternative Crosstalk Between Rage And Nitrative Thioredoxin Inactivation During Diabetic Myocardial Ischemia-Reperfusion Injury., Yi Liu, Yan Qu, Rutao Wang, Yanzhuo Ma, Chenhai Xia, Chao Gao, Jingyi Liu, Kun Lian, Aibing Xu, Xiaoyan Lu, Lu Sun, Lu Yang, Wayne B. Lau, Erhe Gao, Walter Koch, Haichang Wang, Ling Tao

Department of Emergency Medicine Faculty Papers

The receptor for advanced glycation end products (RAGE) and thioredoxin (Trx) play opposing roles in diabetic myocardial ischemia-reperfusion (MI/R) injury. We recently demonstrated nitrative modification of Trx leads to its inactivation and loss of cardioprotection. The present study is to determine the relationship between augmented RAGE expression and diminished Trx activity pertaining to exacerbated MI/R injury in the diabetic heart. The diabetic state was induced in mice by multiple intraperitoneal low-dose streptozotocin injections. RAGE small-interfering RNA (siRNA) or soluble RAGE (sRAGE, a RAGE decoy) was via intramyocardial and intraperitoneal injection before MI/R, respectively. Mice were subjected to 30 min of …

C1q/Tumor Necrosis Factor-Related Protein-3, A Newly Identified Adipokine, Is A Novel Antiapoptotic, Proangiogenic, And Cardioprotective Molecule In The Ischemic Mouse Heart., Wei Yi, Yang Sun, Yuexing Yuan, Wayne Bond Lau, Qijun Zheng, Xiaoliang Wang, Yajing Wang, Xiying Shang, Erhe Gao, Walter J Koch, Xin-Liang Ma

Department of Emergency Medicine Faculty Papers

BACKGROUND: Obesity and diabetes mellitus adversely affect postischemic heart remodeling via incompletely understood mechanisms. C1q/tumor necrosis factor-related protein-3 (CTRP3) is a newly identified adipokine exerting beneficial metabolic regulation, similar to adiponectin. The aim of the present study was to determine whether CTRP3 may regulate postischemic cardiac remodeling and cardiac dysfunction, and, if so, to elucidate the underlying mechanisms.

METHODS AND RESULTS: Male adult mice were subjected to myocardial infarction (MI) via left anterior descending coronary artery occlusion. Both the effect of MI on endogenous CTRP3 expression/production and the effect of exogenous CTRP3 (adenovirus or recombinant CTRP3) replenishment on MI injury …

Essential Role Of Caveolin-3 In Adiponectin Signalsome Formation And Adiponectin Cardioprotection., Yajing Wang, Xiaoliang Wang, Jean-François Jasmin, Wayne Bond Lau, Rong Li, Yuexin Yuan, Wei Yi, Kurt Chuprun, Michael P. Lisanti, Walter J Koch, Erhe Gao, Xin-Liang Ma

Department of Emergency Medicine Faculty Papers

OBJECTIVE: Adiponectin (APN) system malfunction is causatively related to increased cardiovascular morbidity/mortality in diabetic patients. The aim of the current study was to investigate molecular mechanisms responsible for APN transmembrane signaling and cardioprotection.

METHODS AND RESULTS: Compared with wild-type mice, caveolin-3 knockout (Cav-3KO) mice exhibited modestly increased myocardial ischemia/reperfusion injury (increased infarct size, apoptosis, and poorer cardiac function recovery; P

CONCLUSIONS: Taken together, these results demonstrated for the first time that Cav-3 plays an essential role in APN transmembrane signaling and APN anti-ischemic/cardioprotective actions.

Reduced Cardioprotective Action Of Adiponectin In High-Fat Diet-Induced Type Ii Diabetic Mice And Its Underlying Mechanisms., Wei Yi, Yang Sun, Erhe Gao, Xufeng Wei, Wayne Bond Lau, Qijun Zheng, Yajing Wang, Yuexing Yuan, Xiaoliang Wang, Ling Tao, Rong Li, Walter Koch, Xin-Liang Ma

Department of Emergency Medicine Faculty Papers

Diabetes exacerbates ischemic heart disease morbidity and mortality via incompletely understood mechanisms. Although adiponectin (APN) reduces myocardial ischemia/reperfusion (MI/R) injury in nondiabetic animals, whether APN's cardioprotective actions are altered in diabetes, a pathologic condition with endogenously reduced APN, has never been investigated. High-fat diet (HD)-induced diabetic mice and normal diet (ND) controls were subjected to MI via coronary artery ligation, and given vehicle or APN globular domain (gAPN, 2 μg/g) 10 min before reperfusion. Compared to ND mice (where gAPN exerted pronounced cardioprotection), HD mice manifested greater MI/R injury, and a tripled gAPN dose was requisite to achieve cardioprotective extent …

Dynamic Alteration Of Adiponectin/Adiponectin Receptor Expression And Its Impact On Myocardial Ischemia/Reperfusion In Type 1 Diabetic Mice., Yanzhuo Ma, Yi Liu, Shaowei Liu, Yan Qu, Rutao Wang, Chenhai Xia, Haifeng Pei, Kun Lian, Tao Yin, Xiaoyan Lu, Lu Sun, Lu Yang, Yanjie Cao, Wayne Bond Lau, Erhe Gao, Haichang Wang, Ling Tao

Department of Emergency Medicine Faculty Papers

The present study determined the dynamic change of adiponectin (APN, a cardioprotective adipokine), its receptor expression, and their impact upon myocardial ischemia/reperfusion (MI/R) injury during type 1 diabetes mellitus (T1DM) progression, and involved underlying mechanisms. Diabetic state was induced in mice via multiple intraperitoneal injections of low-dose streptozotocin. The dynamic change of plasma APN concentration and cardiac APN receptor-1 and -2 (AdipoR1/2) expression were assessed immediately after diabetes onset (0 wk) and 1, 3, 5, and 7 wk thereafter. Indicators of MI/R injury (infarct size, apoptosis, and LDH release) were determined at 0, 1, and 7 wk of DM duration. …

Cardiomyocyte-Derived Adiponectin Is Biologically Active In Protecting Against Myocardial Ischemia-Reperfusion Injury., Yajing Wang, Wayne Bond Lau, Erhe Gao, Ling Tao, Yuexing Yuan, Rong Li, Xiaoliang Wang, Walter J. Koch, Xin-Liang Ma

Department of Emergency Medicine Faculty Papers

Adiponectin (APN) has traditionally been viewed as an adipocyte-specific endocrine molecule with cardioprotective effects. Recent studies suggest that APN is also expressed in cardiomyocytes. However, biological significances of this locally produced APN remain completely unknown. The aim of this study was to investigate the pathological and pharmacological significance of cardiac-derived APN in cardiomyocyte pathology. Adult cardiomyocytes from wild-type littermates (WT) or gene-deficient mice were pretreated with vehicle (V) or rosiglitazone (RSG) for 6 h followed by simulated ischemia-reperfusion (SI/R, 3 h/12 h). Compared with WT cardiomyocytes, myocytes from APN knockout (APN-KO) mice sustained greater SI/R injury, evidenced by greater oxidative/nitrative …

Cardioprotective Effect Of Adiponectin Is Partially Mediated By Its Ampk-Independent Antinitrative Action., Yajing Wang, Ling Tao, Yuexing Yuan, Wayne Bond Lau, Rong Li, Bernard L. Lopez, Theodore A. Christopher, Rong Tian, Xin-Liang Ma

Department of Emergency Medicine Faculty Papers

Adiponectin (APN) exerts its metabolic regulation largely through AMP-dependent protein kinase (AMPK). However, the role of AMPK in APN's antiapoptotic effect in ischemic-reperfused (I/R) adult cardiomyocytes remains incompletely understood. The present study was designed to determine the involvement of AMPK in the antiapoptotic signaling of APN. Cardiomyocytes from adult male mice overexpressing a dominant-negative alpha(2)-subunit of AMPK (AMPK-DN) or wild-type (WT) littermates were subjected to simulated I/R (SI/R) and pretreated with 2 microg/ml globular domain of APN (gAPN) or vehicle. SI/R-induced cardiomyocyte apoptosis was modestly increased in AMPK-DN cardiomyocytes (P < 0.05). Treatment with gAPN significantly reduced SI/R-induced apoptosis in WT cardiomyocytes as well as in AMPK-DN cardiomyocytes, indicating that the antiapoptotic effect of gAPN is partially AMPK independent. Furthermore, gAPN-induced endothelial nitric oxide synthase (eNOS) phosphorylation was significantly reduced in AMPK-DN cardiomyocytes, suggesting that the APN-eNOS signaling axis is impaired in AMPK-DN cardiomyocytes. Additional experiments demonstrated that treatment of AMPK-DN cardiomyocytes with gAPN reduced SI/R-induced NADPH oxidase overexpression, decreased superoxide generation, and blocked peroxynitrite formation to the same extent as that observed in WT cardiomyocytes. Collectively, our present study demonstrated that although the metabolic and eNOS activation effect of APN is largely mediated by AMPK, the superoxide-suppressing effect of APN is not mediated by AMPK, and this AMPK-independent antioxidant property of APN increased nitric oxide bioavailability and exerted significant antiapoptotic effect.

Heme Oxygenase-2 Gene Deletion Attenuates Oxidative Stress In Neurons Exposed To Extracellular Hemin., Raymond F Regan, Jing Chen, Luna Benvenisti-Zarom

Department of Emergency Medicine Faculty Papers

BACKGROUND: Hemin, the oxidized form of heme, accumulates in intracranial hematomas and is a potent oxidant. Growing evidence suggests that it contributes to delayed injury to surrounding tissue, and that this process is affected by the heme oxygenase enzymes. In a prior study, heme oxygenase-2 gene deletion increased the vulnerability of cultured cortical astrocytes to hemin. The present study tested the effect of HO-2 gene deletion on protein oxidation, reactive oxygen species formation, and cell viability after mixed cortical neuron/astrocyte cultures were incubated with neurotoxic concentrations of hemin. RESULTS: Continuous exposure of wild-type cultures to 1-10 microM hemin for 14 …