Abstract 17169: Endothelium-Specific Reduction in Mitochondrial ROS Induces Coronary Angiogenesis in Ischemic Myocardium via Activation of PI3k/Akt/ERG, ERK1/2, and Jag-1 Signaling

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Rayane Brinck Teixeira ◽  
Melissa Pfeiffer ◽  
Catherine Karbasiafshar ◽  
Giana Blume Corssac ◽  
Nagib Ahsan ◽  
...  
Keyword(s):  
Cardiac Function ◽  
De Novo ◽  
Ischemic Myocardium ◽  
Mouse Heart ◽  
Western Blots ◽  
Mitochondrial Ros ◽  
Acute Mi ◽  
Student’S T ◽  
Related Proteins ◽  
Coronary Angiogenesis

Introduction: Global reduction in reactive oxygen species (ROS) failed to improve outcomes in cardiovascular disease patients. Recent reports suggest that subcellular, rather than global ROS, play a crucial role in endothelial cell (EC) health. To that end, we generated a novel transgenic mouse model that overexpresses mitochondrial antioxidant MnSOD in EC-specific manner (MnSODVE-OE). Hypothesis: We hypothesized that decreased EC mitochondrial-ROS will improve post-myocardial infarction (MI) cardiac function by inducing coronary angiogenesis in ischemic myocardium. Methods: MnSODVE mice were assigned to Tet-ON (control) or Tet-OFF (MnSODVE-OE) group. To turn off the transgene, Tetracycline (Tet) (2mg/kg) was added to the drinking water (Tet-ON), while Tet-OFF mice did not receive Tet. Both groups underwent left anterior descending coronary artery (LAD) ligation surgery to mimic acute MI. Echocardiography was done 28 days after LAD ligation. Capillaries, arteriole density, and proliferating ECs were measured in heart sections using anti-CD31, anti-αSMA, and anti-PCNA immunofluorescence. Western blot, proteomic and phosphoproteomic analyses of mouse heart ECs isolated from MnSODVE (Tet-ON and Tet-OFF) animals were performed to study modulation of signaling cascades. Results: MnSODVE-OE mice demonstrated improved cardiac function (EF and FS increased by 16±7.87% and 21.73±10.31%, respectively, p <0.01), increase in capillary and arteriole densities by 4.13±4.10-fold, p<0.05 and 5.48±3.51-fold, p<0.001, respectively, and in EC proliferation by 1.46±0.80-fold, p <0.01, suggesting de novo coronary angiogenesis. Western blots showed activation of Akt (80.46±3.95% increase in p-Akt/ t-Akt ratio, p<0.05) and ERK1/2 (21.05±4.45% increase in p-ERK/ t-ERK 1/2 ratio, p<0.05). Proteome and phosphoproteome analyses showed upregulation of mitochondrial complex I biogenesis, RNA metabolism, and upregulation of Notch-related proteins ERG and Jag-1 (p<0.05). Student’s t-test was used for data analyses. Conclusions: Taken together, these results suggest that decreased mito-ROS in ECs improves post-MI cardiac function by inducing coronary angiogenesis through activation of PI3k/Akt/ERG, ERK1/2, and Jag-1 signaling.

Abstract 17385: Endothelium Specific Reduction in Mitochondrial ROS Reverses the Deleterious Effects on Coronary Endothelium Caused by Prolonged Increase in NADPH Oxidase Derived ROS

Circulation ◽  
2018 ◽  
Vol 138 (Suppl_1) ◽  
Author(s):  
Isabella McCormack ◽  
Bonnie Colantuono ◽  
Melissa Stanley ◽  
Frank Sellke ◽  
Ruhul Abid
Keyword(s):  
Transgenic Mice ◽  
Nadph Oxidase ◽  
Cardiac Function ◽  
Cardiovascular Health ◽  
Prolonged Exposure ◽  
Capillary Density ◽  
Mouse Heart ◽  
Therapeutic Modalities ◽  
Mitochondrial Ros ◽  
Coronary Endothelium

Introduction: Recent findings from our lab demnstrated that prolonged increase in NADPH oxidase (NOX)-derived ROS results in increased mitochondrial (mito) ROS levels, reduced aspartate/dNTP synthesis, reduced coronary endothelial cell (EC) proliferation, and decreased recovery of post-MI cardiac function. Hypothesis: We hypothesized that endothelium-specific reduction in mitochondrial ROS will reverse the deleterious effects of prolonged NOX-ROS increase by improving mitochondrial function and aspartate/dNTP synthesis. Methods: Tetracycline (Tet)-ON/Tet-OFF binary transgenic mice, Tet-Nox2:VE-Cad-tTA (NOX-OE), were used as a model for endothelium-specific increase in the expression of the catalytic subunit of NADPH oxidase resulting in increased ROS. Mouse heart EC (MHEC) were isolated from Tet-ON and Tet-OFF Tg-Nox2 mice that were exposed to >16 weeks of increased EC-ROS. MHECs were then subject to mitochondrial antioxidants nitroxide (XJB-131) and nanoparticle (CeTiO2) followed by determination of mito-ROS, aspartate/dNTP synthesis, and EC proliferation. NOX-OE was crossbred with SOD-OE to generate a double-transgenic mice with EC-specific overexpression of mitochondrial antioxidant MnSOD (Sod2), Tet-Sod2:Tet-Nox2:VE-Cad-tTA ( SOD-OE ). Both NOX-OE and SOD-OE were subject to myocardial infarction (MI) LAD ligation experiments. Results: Mito-ROS levels were significantly reduced (by >2-fold) in MHEC from SOD-OE compared to NOX-OE. Both dNTP and proliferation were increased in SOD-OE, and also in NOX-EC treated with XJB-131 and CeTiO2. Together, these data suggest that reduction in mito-ROS abrogated negative effects of NOX-ROS in EC. Preliminary data demonstrate that there was an increase in capillary density (by 34± 5.8 %; p<0.05) and angiogenesis (by 2-fold) in SOD-OE post-MI myocardium compared to that of NOX-OE. Infarct sizes and cardiac function between NOX-OE and SOD-OE will be presented. Conclusion: These results suggest that reduction in mito-ROS can abrogate deleterious effects coronary endothelium caused by prolonged exposure to NOX-ROS. EC-specific modulation of mito-ROS may thus help develop therapeutic modalities to improve cardiovascular health and myocardial preservation in the post-MI heart.

scholarly journals Ecklonia cava Attenuates PM2.5-Induced Cognitive Decline through Mitochondrial Activation and Anti-Inflammatory Effect

Marine Drugs ◽  
2021 ◽  
Vol 19 (3) ◽  
pp. 131
Author(s):  
Seon Kyeong Park ◽  
Jin Yong Kang ◽  
Jong Min Kim ◽  
Hyun-Jin Kim ◽  
Ho Jin Heo
Keyword(s):  
Water Extract ◽  
Ecklonia Cava ◽  
Mitochondrial Activity ◽  
Memory Decline ◽  
Mitochondria Membrane Potential ◽  
Mitochondrial Ros ◽  
Ifn Γ ◽  
Related Proteins ◽  
The Brain ◽  
Pro Inflammatory Cytokines

To evaluate the effects of Ecklonia cava (E. cava) on ambient-pollution-induced neurotoxicity, we used a mouse model exposed to particulate matter smaller than 2.5 µm in aerodynamic diameter (PM2.5). The intake of water extract from E. cava (WEE) effectively prevented the learning and memory decline. After a behavioral test, the toll-like receptor (TLR)-4-initiated inflammatory response was confirmed by PM2.5 exposure in the lung and brain tissues, and the WEE was regulated through the inhibition of nuclear factor-kappa B (NF-κB)/inflammasome formation signaling pathway and pro-inflammatory cytokines (IL-6 and IFN-γ). The WEE also effectively improved the PM2.5-induced oxidative damage of the lungs and brain through the inhibition of malondialdehyde (MDA) production and the activation of mitochondrial activity (mitochondrial ROS content, mitochondria membrane potential (MMP), adenosine triphosphate (ATP) content, and mitochondria-mediated apoptotic molecules). In particular, the WEE regulated the cognition-related proteins (a decreased amyloid precursor protein (APP) and p-Tau, and an increased brain-derived neurotrophic factor (BDNF)) associated with PM2.5-induced cognitive dysfunction. Additionally, the WEE prevented the inactivation of acetylcholine (ACh) synthesis and release as a neurotransmitter by regulating the acetylcholinesterase (AChE) activity, choline acetyltransferase (ChAT), and ACh receptor (AChR)-α3 in the brain tissue. The bioactive compounds of the WEE were detected as the polysaccharide (average Mw; 160.13 kDa) and phenolic compounds including 2′-phloroeckol.

scholarly journals High-Throughput Quantitative Assay Technologies for Accelerating the Discovery and Optimization of Targeted Protein Degradation Therapeutics

2021 ◽  
pp. 247255522098504
Author(s):  
Jeffrey R. Simard ◽  
Linda Lee ◽  
Ellen Vieux ◽  
Reina Improgo ◽  
Trang Tieu ◽  
...  
Keyword(s):  
Drug Discovery ◽  
Protein Degradation ◽  
Protein Interactions ◽  
Fluorescent Protein ◽  
De Novo ◽  
Rapid Development ◽  
Dependent Manner ◽  
Western Blots ◽  
Advantages And Disadvantages ◽  
Degradation Rates

The aberrant regulation of protein expression and function can drastically alter cellular physiology and lead to numerous pathophysiological conditions such as cancer, inflammatory diseases, and neurodegeneration. The steady-state expression levels of endogenous proteins are controlled by a balance of de novo synthesis rates and degradation rates. Moreover, the levels of activated proteins in signaling cascades can be further modulated by a variety of posttranslational modifications and protein–protein interactions. The field of targeted protein degradation is an emerging area for drug discovery in which small molecules are used to recruit E3 ubiquitin ligases to catalyze the ubiquitination and subsequent degradation of disease-causing target proteins by the proteasome in both a dose- and time-dependent manner. Traditional approaches for quantifying protein level changes in cells, such as Western blots, are typically low throughput with limited quantification, making it hard to drive the rapid development of therapeutics that induce selective, rapid, and sustained protein degradation. In the last decade, a number of techniques and technologies have emerged that have helped to accelerate targeted protein degradation drug discovery efforts, including the use of fluorescent protein fusions and reporter tags, flow cytometry, time-resolved fluorescence energy transfer (TR-FRET), and split luciferase systems. Here we discuss the advantages and disadvantages associated with these technologies and their application to the development and optimization of degraders as therapeutics.

Abstract 269: Miofibroblast Tgf-beta Signaling in a Proteotoxic Mouse Model

2016 ◽  
Vol 119 (suppl_1) ◽  
Author(s):  
Bidur Bhandary ◽  
Qinghang Meng ◽  
Hanna Osinska ◽  
Kritton Shay-Winkler ◽  
James Gulick ◽  
...  
Keyword(s):  
Heart Disease ◽  
Mouse Model ◽  
Cardiac Function ◽  
Transforming Growth Factor Beta ◽  
Cardiac Fibrosis ◽  
Transforming Growth Factor ◽  
Prolonged Survival ◽  
Tgfβ Signaling ◽  
Specific Expression ◽  
Western Blots

Introduction: Transforming Growth Factor Beta (TGFβ) is an important cytokine in mediating the fibrogenic response and, in particular, cardiac fibrosis. Extensive fibrosis accompanies the cardiac remodeling that occurs during development of the protein conformation-based disease caused by cardiomyocyte-specific expression of a mutant, small, heat shock-like protein and chaperone, aB crystallin (CryABR120G). During the onset of fibrosis, fibroblasts are activated to the so-called “myofibroblast” state and TGFβ binding is thought to mediate an essential signaling pathway underlying this process. Our central hypothesis is that TGFβ signaling processes that result in significant cardiac fibrosis in a mouse model of proteotoxic heart disease are mediated by cardiac fibroblasts, rather than cardiomyocytes. Here, we have partially ablated TGFβ signaling only in cardiac myofibroblasts to observe if cardiac fibrosis is reduced. Aims and Methods: The objective of this study was to understand the contributions of fibroblast-derived TGFβ signaling to the development of cardiac fibrosis in a proteotoxic mouse model that results in significant cardiac fibrosis. To test the hypothesis we partially deleted the myofibroblast specific canonical and non-canonical signaling by crossing CryAB R120G mice with Tgfbr1 or Tgfbr2 floxed mice. The double transgene containing mice were further crossed with activated myofibroblast specific Cre mice in which Cre expression was driven off the periostin promoter. Echocardiography, Masson’s Trichome staining, PCR arrays, IHC and western blots were performed to characterize the fibrotic progression in CryAB R120G transgenic mice. Results: We observed that myofibroblast-targeted partial knockdown of Tgf βr1 signaling prolonged survival, modestly reducing fibrosis and improving cardiac function . Similarly, Tgf βr2 partial knockdown prolonged survival, modestly reducing fibrosis without improving cardiac function during fibrosis development in CryAB R120G mice. Conclusion: These findings suggest that, in a model of proteotoxic heart disease, myofibroblast based TGFβ signaling in the heart may contribute to cardiac hypertrophy/dysfunction but cannot account entirely for the fibrotic response.

Abstract 290: Haemogenic Endocardium Contribute To Definitive Hematopoiesis During Cardiogenesis

2013 ◽  
Vol 113 (suppl_1) ◽  
Author(s):  
Haruko Nakano ◽  
Xiaoqian Liu ◽  
Armin Arshi ◽  
Ben van Handel ◽  
Rajkumar Sasidharan ◽  
...  
Keyword(s):  
De Novo ◽  
Ex Vivo ◽  
Embryonic Stem ◽  
Circulatory System ◽  
Lineage Tracing ◽  
Mouse Heart ◽  
Heart Tube ◽  
Cardiac Progenitors ◽  
Definitive Hematopoiesis

The circulatory system is the first functional organ system that develops during mammalian life. Accumulating evidences suggest that cardiac and endocardial cells can arise from a single common progenitor cell during mammalian cardiogenesis. Notably, these early cardiac progenitors express multiple hematopoietic transcription factors, consistent with previous reports. Indeed, a close relationship among cardiac, endocardial and hematopoietic lineages has been suggested in fly, zebrafish, and embryonic stem cell in vitro differentiation models. However, it is unclear when, where and how this hematopoietic gene program is in operation during in vivo mammalian cardiogenesis. Hematopoietic colony assay suggests that mouse heart explants generate myeloids and erythroids in the absence of circulation, suggesting that the heart tube is a de novo site for the definitive hematopoiesis. Lineage tracing revealed that putative cardiac-derived Nkx2-5+/Isl1+ endocardial cells give rise to CD41+ hematopoietic progenitors that contribute to definitive hematopoiesis in vivo and ex vivo during embryogenesis earlier than in the AGM region. Furthermore, Nkx2-5 and Isl1 are both required for the hemogenic activity of the endocardium. Together, identification of Nkx2-5/Isl1-dependent hemogenic endocardial cells (1) adds hematopoietic component in the cardiogenesis lineage tree, (2) changes the long-held dogma that AGM is the only major source of definitive hematopoiesis in the embryo proper, and (3) represents phylogenetically conserved fundamental mechanism of cardio-vasculo-hematopoietic differentiation pathway during the development of circulatory system.

scholarly journals Galangin Alleviates Liver Ischemia-Reperfusion Injury in a Rat Model by Mediating the PI3K/AKT Pathway

2018 ◽  
Vol 51 (3) ◽  
pp. 1354-1363 ◽  
Author(s):  
Yang Li ◽  
Liquan Tong ◽  
Jingyan Zhang ◽  
Yafeng Zhang ◽  
Feng  Zhang
Keyword(s):  
Oxidative Stress ◽  
Ischemia Reperfusion Injury ◽  
Hepatic Duct ◽  
Ischemia Reperfusion ◽  
Trauma Surgery ◽  
Liver Ischemia ◽  
Western Blots ◽  
Phosphorylated Akt ◽  
Related Proteins

Background/Aims: Liver ischemia-reperfusion (I/R) injury is a pathological process that often occurs during liver and trauma surgery. There are numerous causes of liver I/R injury, but the mechanism is unknown. Galangin (GA) is a flavonoid, a polyphenolic compound widely distributed in medicinal herbs that has anti-inflammatory, antioxidant, and antitumor activity. This study evaluated the protective effect of GA on hepatic I/R injury. Methods: An I/R model was created in male Wistar rats by clamping the hepatoportal vein, hepatic artery and hepatic duct for 30 min followed by reperfusion for 2 h. A hypoxia/restoration (H/R) model was established in buffalo rat liver (BRL) cells by hypoxia for 4 h followed by normoxic conditions for 10 h. The extent of liver injury was assayed by serum ALT/AST, hepatic histology, and MPO activity. Oxidative stress was assayed by serum superoxide dismutase (SOD), catalase (CAT), glutathione (GSH) and malondialdehyde (MDA). Expression of apoptosis-related proteins in BRL cells was assayed in western blots. Expression of AKT and p-AKT proteins in vivo and vitro were assayed in western blots. Results: GA significantly decreased ALT/AST expression, reversed changes in oxidative stress markers induced by I/R, and mediated caspase-3 activity expression of apoptosis-related proteins in vivo and in vitro. Methylthiazol tetrazolium (MTT) assay, flow cytometry, and Hoechst 33258 staining confirmed that GA inhibited apoptosis of BRL cells. GA also increased the expression of phosphorylated AKT after H/R. Conclusion: GA reduced liver I/R injury both in vivo and vitro and inhibited BRL cell apoptosis. PI3K/AKT signaling have been involved. GA may protect against liver I/R and be a potential therapeutic candidate.

Inhibition of mitochondrial fission as a novel therapeutic strategy to reduce mortality upon myocardial infarction

2018 ◽  
Vol 132 (20) ◽  
pp. 2163-2167 ◽  
Author(s):  
Hannah A. Cooper ◽  
Satoru Eguchi
Keyword(s):  
Myocardial Infarction ◽  
Cardiac Function ◽  
Molecular Mechanisms ◽  
Ischemia Reperfusion ◽  
Mitochondrial Fission ◽  
Future Research ◽  
Mitochondrial Homeostasis ◽  
Acute Mi ◽  
Future Research Directions ◽  
Receive Treatment

Ischemia reperfusion (I/R) injury is a common event following myocardial infarction (MI) resulting in excessive oxidative stress, calcium overload, inflammation, and cardiomyocyte death. Mitochondrial homeostasis including their dynamics are imbalanced in cardiac I/R injury in favor of increased mitochondrial fission. Inhibition of mitochondrial fission prior to I/R injury is protective and improves cardiac function following MI. Clinically, patients with MI often receive treatment following initiation of the ischemic event. Thus, treatments with more realistic timing would have better translational value and are important to research. In a recent study published in Clinical Science, Maneechote et al. [Clin. Sci. (2018) 132, 1669–1683] examined the effect of inhibiting mitochondrial fission using the mitochondrial division inhibitor (Mdivi-1) at different time points, pre-ischemia, during-ischemia, and upon onset of reperfusion, in a rat cardiac I/R model. The findings showed the greatest cardiac function improvement with pre-ischemia treatment along with decreased mitochondrial fragmentation and increased mitochondrial function. Mdivi-1 given during ischemia and at onset of reperfusion also improved cardiac function, but to a lesser extent than pre-ischemia intervention. Maneechote et al. postulated that the LV protection by Mdivi-1 in cardiac I/R could be due to an improvement in mitochondrial dysfunction through attenuating excessive mitochondrial fission which then reduces apoptotic myocytes. Their findings provide new insights into future treatment of patients suffering acute MI which could consider targetting the excessive mitochondrial fission during cardiac ischemia or at onset of reperfusion. Here, we will further discuss the background of the study, potential molecular mechanisms of mitochondrial fission, consequences of the fission, and future research directions.

Abstract 3899: SDF-1α Mediates the Therapeutic Effect of Human Adipose-Derived Stem Cells on Acute Myocardial Infarction Recruiting Bone Marrow-Derived Endothelial Progenitor Cells

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Masaaki Ii ◽  
Ayumi Yokoyama ◽  
Miki Horii ◽  
Hiroshi Akimaru ◽  
Takayuki Asahara
Keyword(s):  
Myocardial Infarction ◽  
Stem Cells ◽  
Cardiac Function ◽  
Therapeutic Effect ◽  
Heart Diseases ◽  
Capillary Density ◽  
Ischemic Myocardium ◽  
Control Group ◽  
Adipose Derived Stem Cells ◽  
Ischemic Heart Diseases

Background: Recently, human multipotent adipose-derived stem cells (hMADSs) have been isolated featuring extensive expansion capacity ex vivo. However, little is known about the therapeutic efficacy of hMADS in ischemic heart diseases. We tested the hypothesis that hMADS transplantation may contribute to cardiac functional recovery following myocardial infarction (MI). Methods and Results: Nude rats were either transplanted with hMADSs (5x10 5 /rat, n=10) or PBS (control, n=9) in ischemic myocardium immediately following MI induction. The cardiac function, infarct size and capillary density in the peri-infarct area were evaluated by echocardiography and immunostaining 28 days after surgery. The cardiac function was significantly greater with increased capillary density and reduced fibrosis area in the hMADS group than that in the control group. Next, we examined tissue regeneration in the infarct heart by the transplanted hMADSs. However, remarkable differentiation of hMADSs into any cardiac cell lineages was not detected. To explore another mechanism for the favorable effect of hMADSs, we further examined mRNA expression of cytokines in hMADSs under hypoxic conditions. Although hypoxia decreased the expressions, robust VEGF, bFGF, and SDF-1α expressions were detected in hMADSs. Notably, the stem/progenitor chemokine SDF-1α expression in hMADSs was significantly greater than that in human mesenchymal stem cells that are well known to have a therapeutic effect on ischemic heart diseases. We then focused on SDF-1α /CXCR4 axis and examined the contribution of bone marrow (BM)-derived endothelial progenitor cells (EPCs), that have CXCR4 receptor for SDF-1v, to ischemic myocardium using a Tie2/LacZ BM transplantation nude mouse model. β-gal positive EPCs are frequently observed in ischemic myocardium in the hMADS group compared to the control group. Conclusion: hMADSs exhibit a therapeutic effect on cardiac function following MI with the production of VEGF, bFGF, and SDF-1α demonstrating paracrine effects rather than direct contribution to cardiac regeneration. These findings suggest that transplanted hMADSs and recruited EPCs may synergistically promote angiogenesis playing a role in ischemic myocardium.

Abstract 19979: Endothelium-specific Increase in ROS has Protective Effects on Vascular Endothelium in Ischemic Myocardium

Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Ehtesham Shafique ◽  
Karla Reichert ◽  
Bonnie Colantuono ◽  
Anali Torina ◽  
Elizabeth Harrington ◽  
...  
Keyword(s):  
Nadph Oxidase ◽  
Vascular Endothelium ◽  
Fold Increase ◽  
Capillary Density ◽  
Ischemic Myocardium ◽  
Vascular Pathology ◽  
Mouse Heart ◽  
Protective Effects ◽  
Specific Increase ◽  
Coronary Endothelium

Introduction: Increased ROS is often associated with vascular pathology. Recent findings demonstrated that increases in NADPH oxidase-derived endothelium (EC)-specific ROS improved coronary endothelial function by activating AMPK-eNOS signaling pathway. Here, we examined the effects of EC-ROS on vessel density in post-infarct ischemic myocardium. Hypothesis: We tested the hypothesis that increased EC-ROS induces AMPK-FOXO1-mediated overexpression of mitochondrial antioxidant MnSOD, which in turn has protective effects on vascular endothelium in ischemic myocardium. Methods: Our binary (Tet-ON/OFF) conditional transgenic mouse (Tet-Nox2:VE-Cad-tTA) induces 1.8±0.42-fold increase in NADPH oxidase-derived ROS in endothelium. Using these animals, we have induced myocardial infarction by LAD (left anterior descending) ligation. Results: Co-immunostaining of the ischemic myocardium using anti-CD31 and anti-SMA antibodies demonstrated that there was an increase in capillary density (by 38± 6.45; p<0.05) in Tet-Nox2:VE-Cad-tTA mice with high EC-ROS. Isolated mouse heart ECs showed an increase in AMPK-Foxo1-mediated expression of MnSOD in Tet-Nox2:VE-Cad-tTA mice compared to control. Together, these findings suggest that increase in EC-ROS increases mitochondrial antioxidant MnSOD, which in turn protects coronary endothelium in myocardial ischemia. Conclusion: This study demonstrates that the endothelial ROS may play an important role in myocardial preservation.

Abstract 10246: Hydroxychloroquine Pretreatment Reduces Myocardial Ischemia-Reperfusion Injury: Role of Cardiac Extracellular-Signal-Regulated Kinase 5 and Autophagy

Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Feiyan Yang ◽  
Chang Yin ◽  
Lei Xi ◽  
Rakesh C Kukreja
Keyword(s):  
Infarct Size ◽  
Ischemia Reperfusion Injury ◽  
Myocardial Infarct ◽  
Ischemia Reperfusion ◽  
Beclin 1 ◽  
Myocardial Infarct Size ◽  
Western Blots ◽  
Extracellular Signal Regulated Kinase ◽  
Extracellular Signal ◽  
Related Proteins

Background: Hydroxychloroquine (HCQ) is an antimalarial drug, which is also widely used to treat chronic rheumatologic diseases. Since HCQ was reported to inhibit cell autophagy and to activate extracellular-signal-regulated kinase 5 (ERK5) in vascular endothelial cells, we designed the current study to determine the effects of HCQ on cardiac ischemia-reperfusion (I-R) injury and post-I-R expression of ERK5 and autophagy marker proteins. Methods: Adult C57BL/6J mice of both genders were pretreated with HCQ (50 mg/kg, i.p.) 1 hour prior to isolation of the hearts, which were subjected to 30 min of no-flow global ischemia followed by 60 min of reperfusion in Langendorff mode. Ventricular function was continuously assessed and myocardial infarct size was determined at the end of I-R. Heart samples were collected following normoxic perfusion (no-ischemic controls), I-R, or I-R with HCQ for assessing ERK5 and autophagy-related proteins with Western blots. Results: HCQ pretreatment reduced infarct size significantly in the female hearts (P<0.05) as compared with the male hearts (Fig. A). Post-I-R cardiac function was better in HCQ-treated males (Fig. B). I-R resulted in a robust increase in total ERK5 (Fig. C) and phosphorylated ERK5 (Thr218/Tyr220) in both genders, which was abolished in HCQ-treated groups. Conversely, either I-R or HCQ did not affect the post-I-R cardiac expression of autophagy-related proteins (e.g., Atg5, Beclin-1, LC3II/LC3I ratio), except Beclin-1 phosphorylation was inhibited in HCQ-treated male hearts, but not females (Fig. D). Conclusions: Acute HCQ pretreatment affords cardioprotection against I-R injury in both genders. Interestingly, cardioprotective effects of HCQ are associated with a strong inhibitory effect on the induction of ERK5 following I-R in the heart, indicating a novel molecular mechanism underlying the HCQ-induced cardioprotection. However, the cardioprotective dose of HCQ has no major impact on cardiac autophagy.

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