@article{CochainChaudhariKochetal.2014, author = {Cochain, Clement and Chaudhari, Sweena M. and Koch, Miriam and Wiendl, Heinz and Eckstein, Hans-Henning and Zernecke, Alma}, title = {Programmed Cell Death-1 Deficiency Exacerbates T Cell Activation and Atherogenesis despite Expansion of Regulatory T Cells in Atherosclerosis-Prone Mice}, series = {PLoS ONE}, volume = {9}, journal = {PLoS ONE}, number = {4}, issn = {1932-6203}, doi = {10.1371/journal.pone.0093280}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-119823}, pages = {e93280}, year = {2014}, abstract = {T cell activation represents a double-edged sword in atherogenesis, as it promotes both pro-inflammatory T cell activation and atheroprotective Foxp3(+) regulatory T cell (Treg) responses. Here, we investigated the role of the co-inhibitory receptor programmed cell death-1 (PD-1) in T cell activation and CD4(+) T cell polarization towards pro-atherogenic or atheroprotective responses in mice. Mice deficient for both low density lipoprotein receptor and PD-1 (Ldlr(-/-)Pd1(-/-)) displayed striking increases in systemic CD4(+) and CD8(+) T cell activation after 9 weeks of high fat diet feeding, associated with an expansion of both pro-atherogenic IFNγ-secreting T helper 1 cells and atheroprotective Foxp3+ Tregs. Importantly, PD-1 deficiency did not affect Treg suppressive function in vitro. Notably, PD-1 deficiency exacerbated atherosclerotic lesion growth and entailed a massive infiltration of T cells in atherosclerotic lesions. In addition, aggravated hypercholesterolemia was observed in Ldlr(-/-)Pd1(-/-) mice. In conclusion, we here demonstrate that although disruption of PD-1 signaling enhances both pro- and anti-atherogenic T cell responses in Ldlr(-/-) mice, pro-inflammatory T cell activation prevails and enhances dyslipidemia, vascular inflammation and atherosclerosis.}, language = {en} } @article{HowangyinZlatanovaPintoetal.2016, author = {Howangyin, Kiave-Yune and Zlatanova, Ivana and Pinto, Cristina and Ngkelo, Anta and Cochain, Cl{\´e}ment and Rouanet, Marie and Vilar, Jos{\´e} and Lemitre, Mathilde and Stockmann, Christian and Fleischmann, Bernd K. and Mallat, Ziad and Silvestre, Jean-S{\´e}bastien}, title = {Myeloid-epithelial-reproductive receptor tyrosine kinase and milk fat globule epidermal growth factor 8 coordinately improve remodeling after myocardial infarction via local delivery of vascular endothelial growth factor}, series = {Circulation}, volume = {133}, journal = {Circulation}, number = {9}, doi = {10.1161/CIRCULATIONAHA.115.020857}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-190755}, pages = {826-839}, year = {2016}, abstract = {Background: In infarcted heart, improper clearance of dying cells by activated neighboring phagocytes may precipitate the transition to heart failure. We analyzed the coordinated role of 2 major mediators of efferocytosis, the myeloid-epithelial-reproductive protein tyrosine kinase (Mertk) and the milk fat globule epidermal growth factor (Mfge8), in directing cardiac remodeling by skewing the inflammatory response after myocardial infarction. Methods and Results: We generated double-deficient mice for Mertk and Mfge8 (Mertk\(^{-/-}\)/Mfge8\(^{-/-}\)) and challenged them with acute coronary ligature. Compared with wild-type, Mertk-deficient (Mertk\(^{-/-}\)), or Mfge8-deficient (Mfge8\(^{-/-}\)) animals, Mertk\(^{-/-}\)/Mfge8\(^{-/-}\) mice displayed greater alteration in cardiac function and remodeling. Mertk and Mfge8 were expressed mainly by cardiac Ly6C\(^{High and Low}\) monocytes and macrophages. In parallel, Mertk\(^{-/-}\)/Mfge8\(^{-/-}\) bone marrow chimeras manifested increased accumulation of apoptotic cells, enhanced fibrotic area, and larger infarct size, as well as reduced angiogenesis. We found that the abrogation of efferocytosis affected neither the ability of circulating monocytes to infiltrate cardiac tissue nor the number of resident Ly6C\(^{High}\) and Ly6C\(^{Low}\) monocytes/macrophages populating the infarcted milieu. In contrast, combined Mertk and Mfge8 deficiency in Ly6C\(^{High}\)/Ly6C\(^{Low}\) monocytes/macrophages either obtained from in vitro differentiation of bone marrow cells or isolated from infarcted hearts altered their capacity of efferocytosis and subsequently blunted vascular endothelial growth factor A (VEGFA) release. Using LysMCre\(^+\)/VEGFA\(^{fl/fl}\) mice, we further identified an important role for myeloid-derived VEGFA in improving cardiac function and angiogenesis. Conclusions: After myocardial infarction, Mertk- and Mfge8-expressing monocyte/macrophages synergistically engage the clearance of injured cardiomyocytes, favoring the secretion of VEGFA to locally repair the dysfunctional heart.}, language = {en} }