title: Blockade of Tim-1 and Tim-4 Enhances Atherosclerosis in Low-Density Lipoprotein Receptor-Deficient Mice.
abstract: OBJECTIVE
  T cell immunoglobulin and mucin domain (Tim) proteins are expressed by numerous immune cells, recognize phosphatidylserine on apoptotic cells, and function as costimulators or coinhibitors. Tim-1 is expressed by activated T cells but is also found on dendritic cells and B cells. Tim-4, present on macrophages and dendritic cells, plays a critical role in apoptotic cell clearance, regulates the number of phosphatidylserine-expressing activated T cells, and is genetically associated with low low-density lipoprotein and triglyceride levels. Because these functions of Tim-1 and Tim-4 could affect atherosclerosis, their modulation has potential therapeutic value in cardiovascular disease.
  
  
  RESULTS
  ldlr(-/-) mice were fed a high-fat diet for 4 weeks while being treated with control (rat immunoglobulin G1) or anti-Tim-1 (3D10) or -Tim-4 (21H12) monoclonal antibodies that block phosphatidylserine recognition and phagocytosis. Both anti-Tim-1 and anti-Tim-4 treatments enhanced atherosclerosis by 45% compared with controls by impairment of efferocytosis and increasing aortic CD4(+)T cells. Consistently, anti-Tim-4-treated mice showed increased percentages of activated T cells and late apoptotic cells in the circulation. Moreover, in vitro blockade of Tim-4 inhibited efferocytosis of oxidized low-density lipoprotein-induced apoptotic macrophages. Although anti-Tim-4 treatment increased T helper cell (Th)1 and Th2 responses, anti-Tim-1 induced Th2 responses but dramatically reduced the percentage of regulatory T cells. Finally, combined blockade of Tim-1 and Tim-4 increased atherosclerotic lesion size by 59%.
  
  
  CONCLUSIONS
  Blockade of Tim-4 aggravates atherosclerosis likely by prevention of phagocytosis of phosphatidylserine-expressing apoptotic cells and activated T cells by Tim-4-expressing cells, whereas Tim-1-associated effects on atherosclerosis are related to changes in Th1/Th2 balance and reduced circulating regulatory T cells.
authors.affiliation: From the Department of Pathology (A.C.F., D.E., F.K., N.A.-G., P.J., A.H.L.) and Department of Surgery (J.L.), Harvard Medical School, Brigham and Women's Hospital, Boston, MA; Department of Medicine, University of California, San Diego, La Jolla (A.G., J.L.W.); Department of Medicine, Stanford University, Stanford, CA (R.H.D.); and Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA (G.J.F.).
authors.forename: Amanda C
authors.initials: AC
authors.lastname: Foks
authors.affiliation: From the Department of Pathology (A.C.F., D.E., F.K., N.A.-G., P.J., A.H.L.) and Department of Surgery (J.L.), Harvard Medical School, Brigham and Women's Hospital, Boston, MA; Department of Medicine, University of California, San Diego, La Jolla (A.G., J.L.W.); Department of Medicine, Stanford University, Stanford, CA (R.H.D.); and Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA (G.J.F.).
authors.forename: Daniel
authors.initials: D
authors.lastname: Engelbertsen
authors.affiliation: From the Department of Pathology (A.C.F., D.E., F.K., N.A.-G., P.J., A.H.L.) and Department of Surgery (J.L.), Harvard Medical School, Brigham and Women's Hospital, Boston, MA; Department of Medicine, University of California, San Diego, La Jolla (A.G., J.L.W.); Department of Medicine, Stanford University, Stanford, CA (R.H.D.); and Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA (G.J.F.).
authors.forename: Felicia
authors.initials: F
authors.lastname: Kuperwaser
authors.affiliation: From the Department of Pathology (A.C.F., D.E., F.K., N.A.-G., P.J., A.H.L.) and Department of Surgery (J.L.), Harvard Medical School, Brigham and Women's Hospital, Boston, MA; Department of Medicine, University of California, San Diego, La Jolla (A.G., J.L.W.); Department of Medicine, Stanford University, Stanford, CA (R.H.D.); and Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA (G.J.F.).
authors.forename: Noah
authors.initials: N
authors.lastname: Alberts-Grill
authors.affiliation: From the Department of Pathology (A.C.F., D.E., F.K., N.A.-G., P.J., A.H.L.) and Department of Surgery (J.L.), Harvard Medical School, Brigham and Women's Hospital, Boston, MA; Department of Medicine, University of California, San Diego, La Jolla (A.G., J.L.W.); Department of Medicine, Stanford University, Stanford, CA (R.H.D.); and Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA (G.J.F.).
authors.forename: Ayelet
authors.initials: A
authors.lastname: Gonen
authors.affiliation: From the Department of Pathology (A.C.F., D.E., F.K., N.A.-G., P.J., A.H.L.) and Department of Surgery (J.L.), Harvard Medical School, Brigham and Women's Hospital, Boston, MA; Department of Medicine, University of California, San Diego, La Jolla (A.G., J.L.W.); Department of Medicine, Stanford University, Stanford, CA (R.H.D.); and Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA (G.J.F.).
authors.forename: Joseph L
authors.initials: JL
authors.lastname: Witztum
authors.affiliation: From the Department of Pathology (A.C.F., D.E., F.K., N.A.-G., P.J., A.H.L.) and Department of Surgery (J.L.), Harvard Medical School, Brigham and Women's Hospital, Boston, MA; Department of Medicine, University of California, San Diego, La Jolla (A.G., J.L.W.); Department of Medicine, Stanford University, Stanford, CA (R.H.D.); and Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA (G.J.F.).
authors.forename: James
authors.initials: J
authors.lastname: Lederer
authors.affiliation: From the Department of Pathology (A.C.F., D.E., F.K., N.A.-G., P.J., A.H.L.) and Department of Surgery (J.L.), Harvard Medical School, Brigham and Women's Hospital, Boston, MA; Department of Medicine, University of California, San Diego, La Jolla (A.G., J.L.W.); Department of Medicine, Stanford University, Stanford, CA (R.H.D.); and Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA (G.J.F.).
authors.forename: Petr
authors.initials: P
authors.lastname: Jarolim
authors.affiliation: From the Department of Pathology (A.C.F., D.E., F.K., N.A.-G., P.J., A.H.L.) and Department of Surgery (J.L.), Harvard Medical School, Brigham and Women's Hospital, Boston, MA; Department of Medicine, University of California, San Diego, La Jolla (A.G., J.L.W.); Department of Medicine, Stanford University, Stanford, CA (R.H.D.); and Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA (G.J.F.).
authors.forename: Rosemarie H
authors.initials: RH
authors.lastname: DeKruyff
authors.affiliation: From the Department of Pathology (A.C.F., D.E., F.K., N.A.-G., P.J., A.H.L.) and Department of Surgery (J.L.), Harvard Medical School, Brigham and Women's Hospital, Boston, MA; Department of Medicine, University of California, San Diego, La Jolla (A.G., J.L.W.); Department of Medicine, Stanford University, Stanford, CA (R.H.D.); and Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA (G.J.F.).
authors.forename: Gordon J
authors.initials: GJ
authors.lastname: Freeman
authors.affiliation: From the Department of Pathology (A.C.F., D.E., F.K., N.A.-G., P.J., A.H.L.) and Department of Surgery (J.L.), Harvard Medical School, Brigham and Women's Hospital, Boston, MA; Department of Medicine, University of California, San Diego, La Jolla (A.G., J.L.W.); Department of Medicine, Stanford University, Stanford, CA (R.H.D.); and Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA (G.J.F.). alichtman@partners.org.
authors.forename: Andrew H
authors.initials: AH
authors.lastname: Lichtman
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000633:toxicity*; D001018:Aortic Diseases / Q000139:chemically induced* / Q000235:genetics / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D017209:Apoptosis / Q000187:drug effects; D050197:Atherosclerosis / Q000139:chemically induced* / Q000235:genetics / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D015496:CD4-Positive T-Lymphocytes / Q000187:drug effects* / Q000276:immunology / Q000473:pathology; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D018920:Coculture Techniques; D059305:Diet, High-Fat; D004195:Disease Models, Animal; D005260:Female; D000072596:Hepatitis A Virus Cellular Receptor 1; D008077:Lipoproteins, LDL / Q000378:metabolism; D008213:Lymphocyte Activation / Q000187:drug effects; D008264:Macrophages / Q000187:drug effects* / Q000276:immunology / Q000473:pathology; D008297:Male; D008565:Membrane Proteins / Q000037:antagonists & inhibitors* / Q000276:immunology / Q000378:metabolism; D018345:Mice, Knockout; D010587:Phagocytosis / Q000187:drug effects; D058226:Plaque, Atherosclerotic; D011973:Receptors, LDL / Q000172:deficiency* / Q000235:genetics; D015398:Signal Transduction / Q000187:drug effects; D050378:T-Lymphocytes, Regulatory / Q000187:drug effects / Q000276:immunology; D018417:Th1 Cells / Q000187:drug effects / Q000276:immunology; D018418:Th2 Cells / Q000187:drug effects / Q000276:immunology
chemical_list: D000911:Antibodies, Monoclonal; C442240:Havcr1 protein, mouse; D000072596:Hepatitis A Virus Cellular Receptor 1; D008077:Lipoproteins, LDL; D008565:Membrane Proteins; D011973:Receptors, LDL; C500399:TIM-4 protein, mouse; C099252:oxidized low density lipoprotein
keywords: T cells; Tim; apoptosis; atherosclerosis; inflammation; macrophage
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