Monocyte-specific Bcl-2 expression attenuates inflammation and heart failure in monocyte chemoattractant protein-1 (MCP-1)-induced cardiomyopathy.
OBJECTIVE
Infiltrating inflammatory cells within the myocardium have been shown to be apoptotic, but the significance of apoptotic inflammatory cells to the development of cardiomyopathy remains undefined. Transgenic mice with cardiac-specific expression of MCP-1 exhibit extensive apoptosis of infiltrating mononuclear cells and develop heart failure. Here, we tested the hypothesis that in vivo selective inhibition of apoptosis of infiltrating mononuclear cells would preserve cardiac structure and function and improve survival in this murine model.


METHODS
Mice with cardiac-specific expression of MCP-1 and monocyte-specific expression of Bcl-2 were generated by cross-breeding MCP-1 transgenic mice with hMRP8-Bcl-2 mice that over-express Bcl-2 in the monocytes. Structural and functional parameters and the inflammatory response of the heart were evaluated and compared between the wild-type and transgenic mice.


RESULTS
Expression of Bcl-2 in monocytes results in superior preservation of myocardial structure, cardiac function and a significant prolongation of survival of MCP-1 transgenic mice. The beneficial effects of monocyte-specific Bcl-2 expression are associated with inhibition of apoptosis of infiltrating mononuclear cells, normalization of circulating C-reactive protein levels, attenuation of cellular infiltrates, macrophage activation and production of proinflammatory cytokines, tumor necrosis factor (TNF-alpha), interleukin (IL)-1 beta and IL-6 in the hearts.


CONCLUSIONS
These results demonstrate that apoptosis of infiltrating mononuclear cells plays a detrimental role in the development of heart failure in this murine model, suggesting that modulation of apoptosis of infiltrating mononuclear cells may be of clinical benefit in heart failure.
Niu
Jianli
J
Biomolecular Science Center and Department of Molecular Biology and Microbiology, Burnett College of Biomedical Science, University of Central Florida, FL 32816, USA. jniu@mail.ucf.edu
Azfer
Asim
A
Kolattukudy
Pappachan E
PE
D000818:Animals; D017209:Apoptosis; D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein / Q000032:analysis; D018932:Chemokine CCL2 / Q000235:genetics / Q000378:metabolism*; D002634:Chemotaxis, Leukocyte; D004452:Echocardiography; D015870:Gene Expression; D006333:Heart Failure / Q000276:immunology* / Q000378:metabolism; D007150:Immunohistochemistry / Q000379:methods; D020287:In Situ Nick-End Labeling; D053583:Interleukin-1beta / Q000097:blood; D015850:Interleukin-6 / Q000097:blood; D008214:Lymphocytes / Q000378:metabolism* / Q000473:pathology; D008262:Macrophage Activation; D051379:Mice; D008817:Mice, Mutant Strains; D008822:Mice, Transgenic; D009206:Myocardium / Q000378:metabolism* / Q000473:pathology; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016019:Survival Analysis; D014409:Tumor Necrosis Factor-alpha / Q000097:blood
D015415:Biomarkers; D018932:Chemokine CCL2; D053583:Interleukin-1beta; D015850:Interleukin-6; D019253:Proto-Oncogene Proteins c-bcl-2; D014409:Tumor Necrosis Factor-alpha; D002097:C-Reactive Protein