Mcp-1 Causes Cardiomyoblast Death Via Autophagy Resulting From Er Stress Caused By Oxidative Stress Generated By Inducing A Novel Zinc-Finger Protein, Mcpip

MCP-1 (monocyte chemotactic protein-1) plays a critical role in the development of heart failure that is known to involve apoptosis. How MCP-1 contributes to cell death involved in the development of heart disease is not understood. In the present study we show that MCP-1 causes death in cardiac myoblasts, H9c2 cells, by inducing oxidative stress which causes ER stress leading to autophagy via a novel zinc-finger protein, MCPIP (MCP-1-induced protein). MCPIP expression caused cell death, and knockdown of MCPIP attenuated MCP-1-induced cell death. It caused induction of iNOS (inducible NO synthase), translocation of the NADPH oxidase subunit phox47 from the cytoplasm to the membrane, production of ROS (reactive oxygen species), and induction of ER (endoplasmic reticulum) stress markers HSP40 (heat-shock protein 40), PDI (protein disulfide-isomerase), GRP78 (guanine-nucleotide-releasing protein 78) and IRE1α (inositol-requiring enzyme 1α). It also caused autophagy, as indicated by beclin-1 induction, cleavage of LC3 (microtubule-associated protein 1 light chain 3) and autophagolysosome formation, and apoptosis, as indicated by caspase 3 activation and TUNEL (terminal deoxynucleotidyltransferase-mediated dUTP nick-end labelling) assay. Inhibitors of oxidative stress, including CeO2 nanoparticles, inhibited ROS formation, ER stress, autophagy and cell death. Specific inhibitors of ER stress inhibited autophagy and cell death as did knockdown of the ER stress signalling protein IRE1. Knockdown of beclin-1 and autophagy inhibitors prevented cell death. This cell death involved caspase 2 and caspase 12, as specific inhibitors of these caspases prevented MCPIP-induced cell death. Microarray analysis showed that MCPIP expression caused induction of a variety of genes known to be involved in cell death. MCPIP caused activation of JNK(c-Jun N-terminal kinase) and p38 and induction of p53 and PUMA (p53 up-regulated modulator of apoptosis). Taken together, these results suggest that MCPIP induces ROS/RNS (reactive nitrogen species) production that causes ER stress which leads to autophagy and apoptosis through caspase 2/12 and IRE1α-JNK/p38-p53-PUMA pathway. These results provide the first molecular insights into the mechanism by which elevated MCP-1 levels associated with chronic inflammation may contribute to the development of heart failure. © The Authors Journal compilation © 2010 Biochemical Society

Hyperglycaemia-Induced Cardiomyocyte Death Is Mediated Via Mcp-1 Production And Induction Of A Novel Zinc-Finger Protein Mcpip

Aims Cardiomyocyte apoptosis contributes to the development of diabetic cardiomyopathy. How the elevated glucose levels associated with diabetes cause cell death is unknown. Here we report that high glucose-induced cardiomyocyte death is mediated via monocyte chemotactic protein-1 (MCP-1) production and induction of a novel zinc-finger protein. Methods and results H9c2 cardiomyoblasts treated with 28 mmol/L glucose were evaluated for MCP-1 production and induction of the zinc-finger protein, MCP-1-induced protein (MCPIP). Disruptors of MCP-1 interaction with its receptor, CCR2, and knockdown of MCPIP with siRNA were used to determine if MCP-1 and MCPIP mediate glucose-induced cell death. The molecular mechanisms were evaluated by assessing reactive oxygen species (ROS) production, endoplasmic reticulum (ER) stress, and autophagy. Key findings were confirmed in isolated neonatal rat cardiomyocytes. Glucose treatment of H9c2 cardiomyoblasts and isolated cardiomyocytes caused MCP-1 production, MCPIP induction, ROS production, ER stress, autophagy, and cell death. Treatment with CCR2 antagonists and knockdown of MCPIP attenuated glucose-induced ROS production, ER stress, autophagy, and cell death. Inhibition of ROS with 1400 W, tiron, and cerium oxide (CeO 2) nanoparticles attenuated ER stress, autophagy, and cell death. Specific inhibitors of ER stress and knockdown of IRE-1 attenuated glucose-induced autophagy and cell death. Inhibitors of autophagy and knockdown of beclin-1 attenuated glucose-induced death. Conclusion Glucose-induced cardiomyocyte death is mediated via MCP-1 production and MCPIP induction, which causes sequential events-ROS production, ER stress, autophagy, and cell death. © 2010 The Author

Exendin-4 Improves Cardiac Function In Mice Overexpressing Monocyte Chemoattractant Protein-1 In Cardiomyocytes

The incretin hormone glucagon-like peptide-1 (Glp1) is cardioprotective in models of ischemia-reperfusion injury, myocardial infarction and gluco/lipotoxicity. Inflammation is a factor in these models, yet it is unknown whether Glp1 receptor (Glp1r) agonists are protective against cardiac inflammation. We tested the hypothesis that the Glp1r agonist Exendin-4 (Ex4) is cardioprotective in mice with cardiac-specific monocyte chemoattractant protein-1 overexpression. These MHC-MCP1 mice exhibit increased cardiac monocyte infiltration, endoplasmic reticulum (ER) stress, apoptosis, fibrosis and left ventricular dysfunction. Ex4 treatment for 8. weeks improved cardiac function and reduced monocyte infiltration, fibrosis and apoptosis in MHC-MCP1 mice. Ex4 enhanced expression of the ER chaperone glucose-regulated protein-78 (GRP78), decreased expression of the pro-apoptotic ER stress marker CCAAT/-enhancer-binding protein homologous protein (CHOP) and increased expression of the ER calcium regulator Sarco/Endoplasmic Reticulum Calcium ATPase-2a (SERCA2a). These findings suggest that the Glp1r is a viable target for treating cardiomyopathies associated with stimulation of pro-inflammatory factors

Hyperglycaemia-induced cardiomyocyte death is mediated via MCP-1 production and induction of a novel zinc-finger protein MCPIP

Aims Cardiomyocyte apoptosis contributes to the development of diabetic cardiomyopathy. How the elevated glucose levels associated with diabetes cause cell death is unknown. Here we report that high glucose-induced cardiomyocyte death is mediated via monocyte chemotactic protein-1 (MCP-1) production and induction of a novel zinc-finger protein. Methods and results H9c2 cardiomyoblasts treated with 28 mmol/L glucose were evaluated for MCP-1 production and induction of the zinc-finger protein, MCP-1-induced protein (MCPIP). Disruptors of MCP-1 interaction with its receptor, CCR2, and knockdown of MCPIP with siRNA were used to determine if MCP-1 and MCPIP mediate glucose-induced cell death. The molecular mechanisms were evaluated by assessing reactive oxygen species (ROS) production, endoplasmic reticulum (ER) stress, and autophagy. Key findings were confirmed in isolated neonatal rat cardiomyocytes. Glucose treatment of H9c2 cardiomyoblasts and isolated cardiomyocytes caused MCP-1 production, MCPIP induction, ROS production, ER stress, autophagy, and cell death. Treatment with CCR2 antagonists and knockdown of MCPIP attenuated glucose-induced ROS production, ER stress, autophagy, and cell death. Inhibition of ROS with 1400 W, tiron, and cerium oxide (CeO 2) nanoparticles attenuated ER stress, autophagy, and cell death. Specific inhibitors of ER stress and knockdown of IRE-1 attenuated glucose-induced autophagy and cell death. Inhibitors of autophagy and knockdown of beclin-1 attenuated glucose-induced death. Conclusion Glucose-induced cardiomyocyte death is mediated via MCP-1 production and MCPIP induction, which causes sequential events-ROS production, ER stress, autophagy, and cell death. © 2010 The Author

MCP-1 (Monocyte Chemotactic Protein-1)-induced Protein, a Recently Identified Zinc Finger Protein, Induces Adipogenesis in 3T3-L1 Pre-adipocytes without Peroxisome Proliferator-activated Receptor γ*

Adipogenesis is a key differentiation process relevant to obesity and associated diseases such as type 2 diabetes. This process involves temporally regulated genes controlled by a set of transcription factors, CCAAT/enhancer-binding proteins (C/EBP) β, C/EBPδ, and C/EBPα and peroxisome proliferator-activated receptor γ (PPARγ). Currently, PPARγ is universally accepted as the master regulator that is necessary and sufficient to induce adipogenesis as no known factor can induce adipogenesis without PPARγ. We present evidence that a novel zinc finger protein, MCP-1-induced protein (MCPIP), can induce adipogenesis without PPARγ. Classical adipogenesis-inducing medium induces MCP-1 production and expression of MCPIP in 3T3-L1 cells before the induction of the C/EBP family of transcription factors and PPARγ. Knockdown of MCPIP prevents their expression and adipogenesis as measured by expression of adipocyte markers and lipid droplet accumulation. Treatment of 3T3-L1 cells with MCP-1 or forced expression of MCPIP induces expression of C/EBPβ, C/EBPδ, C/EBPα, and PPARγ and adipogenesis without any other inducer. Forced expression of MCPIP induces expression of the C/EBP family of transcription factors and adipogenesis in PPARγ−/− mouse embryonic fibroblasts. Thus, MCPIP is a newly identified protein that can induce adipogenesis without PPARγ