CD4+ natural killer T cells potently augment aortic root atherosclerosis by perforin- and granzyme B-dependent cytotoxicity.
BACKGROUND
CD4(+) natural killer T (NKT) cells augment atherosclerosis in apolipoprotein E-deficient (ApoE)(-/-) mice but their mechanisms of action are unknown.


OBJECTIVE
We investigated the roles of bystander T, B, and NK cells; NKT cell-derived interferon-γ, interleukin (IL)-4, and IL-21 cytokines; and NKT cell-derived perforin and granzyme B cytotoxins in promoting CD4(+) NKT cell atherogenicity.


RESULTS
Transfer of CD4(+) NKT cells into T- and B-cell-deficient ApoE(-/-)Rag2(-/-) mice augmented aortic root atherosclerosis by ≈75% that was ≈30% of lesions in ApoE(-/-) mice; macrophage accumulation similarly increased. Transferred NKT cells were identified in the liver and atherosclerotic lesions of recipient mice. Transfer of CD4(+) NKT cells into T-, B-cell-deficient, and NK cell-deficient ApoE(-/-)Rag2(-/-)γC(-/-) mice also augmented atherosclerosis. These data indicate that CD4(+) NKT cells can exert proatherogenic effects independent of other lymphocytes. To investigate the role of NKT cell-derived interferon-γ, IL-4, and IL-21 cytokines and perforin and granzyme B cytotoxins, CD4(+) NKT cells from mice deficient in these molecules were transferred into NKT cell-deficient ApoE(-/-)Jα18(-/-) mice. CD4(+) NKT cells deficient in IL-4, interferon-γ, or IL-21 augmented atherosclerosis in ApoE(-/-)Jα18(-/-) mice by ≈95%, ≈80%, and ≈70%, respectively. Transfer of CD4(+) NKT cells deficient in perforin or granzyme B failed to augment atherosclerosis. Apoptotic cells, necrotic cores, and proinflammatory VCAM-1 (vascular cell adhesion molecule) and MCP-1 (monocyte chemotactic protein) were reduced in mice receiving perforin-deficient NKT cells. CD4(+) NKT cells are twice as potent as CD4(+) T cells in promoting atherosclerosis.


CONCLUSIONS
CD4(+) NKT cells potently promote atherosclerosis by perforin and granzyme B-dependent apoptosis that increases postapoptotic necrosis and inflammation.
From the BakerIDI Heart and Diabetes Institute, Melbourne, Australia (L.Y., K.T., P.K., H.H., V.D., A.B., T.K.); Department of Medicine, Centre for Inflammatory Diseases, Southern Clinical School (L.Y., K.T., P.T., B.-H.T., T.K.) and Department of Immunology, Central Clinical School, Faculty of Medicine Nursing and Health Sciences (A.B.), Monash University, Melbourne, Australia; Immunology in Cancer and Infection Laboratory, QIMR Berghofer Medical Research Institute, Herston, Queensland, Australia (M.J.S.); and School of Medicine, University of Queensland, Herston, Queensland, Australia (M.J.S.).
Yi
Y
Li
From the BakerIDI Heart and Diabetes Institute, Melbourne, Australia (L.Y., K.T., P.K., H.H., V.D., A.B., T.K.); Department of Medicine, Centre for Inflammatory Diseases, Southern Clinical School (L.Y., K.T., P.T., B.-H.T., T.K.) and Department of Immunology, Central Clinical School, Faculty of Medicine Nursing and Health Sciences (A.B.), Monash University, Melbourne, Australia; Immunology in Cancer and Infection Laboratory, QIMR Berghofer Medical Research Institute, Herston, Queensland, Australia (M.J.S.); and School of Medicine, University of Queensland, Herston, Queensland, Australia (M.J.S.).
Kelly
K
To
From the BakerIDI Heart and Diabetes Institute, Melbourne, Australia (L.Y., K.T., P.K., H.H., V.D., A.B., T.K.); Department of Medicine, Centre for Inflammatory Diseases, Southern Clinical School (L.Y., K.T., P.T., B.-H.T., T.K.) and Department of Immunology, Central Clinical School, Faculty of Medicine Nursing and Health Sciences (A.B.), Monash University, Melbourne, Australia; Immunology in Cancer and Infection Laboratory, QIMR Berghofer Medical Research Institute, Herston, Queensland, Australia (M.J.S.); and School of Medicine, University of Queensland, Herston, Queensland, Australia (M.J.S.).
Peter
P
Kanellakis
From the BakerIDI Heart and Diabetes Institute, Melbourne, Australia (L.Y., K.T., P.K., H.H., V.D., A.B., T.K.); Department of Medicine, Centre for Inflammatory Diseases, Southern Clinical School (L.Y., K.T., P.T., B.-H.T., T.K.) and Department of Immunology, Central Clinical School, Faculty of Medicine Nursing and Health Sciences (A.B.), Monash University, Melbourne, Australia; Immunology in Cancer and Infection Laboratory, QIMR Berghofer Medical Research Institute, Herston, Queensland, Australia (M.J.S.); and School of Medicine, University of Queensland, Herston, Queensland, Australia (M.J.S.).
Hamid
H
Hosseini
From the BakerIDI Heart and Diabetes Institute, Melbourne, Australia (L.Y., K.T., P.K., H.H., V.D., A.B., T.K.); Department of Medicine, Centre for Inflammatory Diseases, Southern Clinical School (L.Y., K.T., P.T., B.-H.T., T.K.) and Department of Immunology, Central Clinical School, Faculty of Medicine Nursing and Health Sciences (A.B.), Monash University, Melbourne, Australia; Immunology in Cancer and Infection Laboratory, QIMR Berghofer Medical Research Institute, Herston, Queensland, Australia (M.J.S.); and School of Medicine, University of Queensland, Herston, Queensland, Australia (M.J.S.).
Virginie
V
Deswaerte
From the BakerIDI Heart and Diabetes Institute, Melbourne, Australia (L.Y., K.T., P.K., H.H., V.D., A.B., T.K.); Department of Medicine, Centre for Inflammatory Diseases, Southern Clinical School (L.Y., K.T., P.T., B.-H.T., T.K.) and Department of Immunology, Central Clinical School, Faculty of Medicine Nursing and Health Sciences (A.B.), Monash University, Melbourne, Australia; Immunology in Cancer and Infection Laboratory, QIMR Berghofer Medical Research Institute, Herston, Queensland, Australia (M.J.S.); and School of Medicine, University of Queensland, Herston, Queensland, Australia (M.J.S.).
Peter
P
Tipping
From the BakerIDI Heart and Diabetes Institute, Melbourne, Australia (L.Y., K.T., P.K., H.H., V.D., A.B., T.K.); Department of Medicine, Centre for Inflammatory Diseases, Southern Clinical School (L.Y., K.T., P.T., B.-H.T., T.K.) and Department of Immunology, Central Clinical School, Faculty of Medicine Nursing and Health Sciences (A.B.), Monash University, Melbourne, Australia; Immunology in Cancer and Infection Laboratory, QIMR Berghofer Medical Research Institute, Herston, Queensland, Australia (M.J.S.); and School of Medicine, University of Queensland, Herston, Queensland, Australia (M.J.S.).
Mark J
MJ
Smyth
From the BakerIDI Heart and Diabetes Institute, Melbourne, Australia (L.Y., K.T., P.K., H.H., V.D., A.B., T.K.); Department of Medicine, Centre for Inflammatory Diseases, Southern Clinical School (L.Y., K.T., P.T., B.-H.T., T.K.) and Department of Immunology, Central Clinical School, Faculty of Medicine Nursing and Health Sciences (A.B.), Monash University, Melbourne, Australia; Immunology in Cancer and Infection Laboratory, QIMR Berghofer Medical Research Institute, Herston, Queensland, Australia (M.J.S.); and School of Medicine, University of Queensland, Herston, Queensland, Australia (M.J.S.).
Ban-Hock
BH
Toh
From the BakerIDI Heart and Diabetes Institute, Melbourne, Australia (L.Y., K.T., P.K., H.H., V.D., A.B., T.K.); Department of Medicine, Centre for Inflammatory Diseases, Southern Clinical School (L.Y., K.T., P.T., B.-H.T., T.K.) and Department of Immunology, Central Clinical School, Faculty of Medicine Nursing and Health Sciences (A.B.), Monash University, Melbourne, Australia; Immunology in Cancer and Infection Laboratory, QIMR Berghofer Medical Research Institute, Herston, Queensland, Australia (M.J.S.); and School of Medicine, University of Queensland, Herston, Queensland, Australia (M.J.S.).
Alexander
A
Bobik
From the BakerIDI Heart and Diabetes Institute, Melbourne, Australia (L.Y., K.T., P.K., H.H., V.D., A.B., T.K.); Department of Medicine, Centre for Inflammatory Diseases, Southern Clinical School (L.Y., K.T., P.T., B.-H.T., T.K.) and Department of Immunology, Central Clinical School, Faculty of Medicine Nursing and Health Sciences (A.B.), Monash University, Melbourne, Australia; Immunology in Cancer and Infection Laboratory, QIMR Berghofer Medical Research Institute, Herston, Queensland, Australia (M.J.S.); and School of Medicine, University of Queensland, Herston, Queensland, Australia (M.J.S.). tinsoe.kyaw@bakeridi.edu.au.
Tin
T
Kyaw
D019264:Adoptive Transfer / Q000379:methods; D000818:Animals; D050197:Atherosclerosis / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism*; D053804:Granzymes / Q000172:deficiency*; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D055611:Natural Killer T-Cells / Q000276:immunology / Q000378:metabolism*; D052899:Pore Forming Cytotoxic Proteins / Q000172:deficiency*; D012850:Sinus of Valsalva / Q000276:immunology / Q000378:metabolism* / Q000473:pathology
D052899:Pore Forming Cytotoxic Proteins; C483886:perforin, mouse; D053804:Granzymes; C509214:Gzmb protein, mouse
atherosclerosis; cell death; granzymes; inflammation; natural killer T cells; perforin