title: Lck Inhibits Heat Shock Protein 65-Mediated Reverse Cholesterol Transport in T Cells.
abstract: Previously, we reported that heat shock protein (HSP)65 impairs the effects of high-density lipoprotein on macrophages. We also showed that immune response activation adversely affects reverse cholesterol transport (RCT). In this study, we investigated the effects of the Src family kinase lymphocyte-specific protein tyrosine kinase (Lck) and elucidated the mechanism underlying HSP65-regulated cholesterol efflux in T cells. We evaluated cell proliferation, Lck expression, and inflammatory cytokine production in Jurkat cells and CD4+T cells. HSP65-mediated inhibition of RCT was assessed by evaluating ABCA1, ABCG1, SR-BI, PPAR-γ, and liver X receptor-α expression. A dose-dependent relationship was found between the levels of these proteins and the suppression of cholesterol efflux. Stimulation of Lck-silenced T cells with ionomycin resulted in a decrease in intracellular calcium levels. Treatment of Jurkat cells with PP2, an inhibitor of Src family kinase, inhibited calcium-induced, but not PMA-induced, ERK phosphorylation. NF-κB activation in response to PMA was minimally inhibited in cells stimulated with PP2. HSP65 failed to trigger downstream ERK or JNK phosphorylation or to activate NF-κB or protein kinase C-γ in Lck-silenced cells. Additionally, elevation of intracellular calcium was also impaired. However, HSP65 significantly enhanced cholesterol efflux and decreased cellular cholesterol content by inducing the expression of cholesterol transport proteins in Lck-silenced cells. The treatment of Jurkat cells with PP2 also inhibited cell proliferation and promoted RCT. In conclusion, Lck is a key molecule in the TCR signaling cascade that inhibits cholesterol efflux and upregulates intracellular cholesterol ester content in T cells. Our results demonstrate that the immune response plays a previously unrecognized role in RCT.
authors.affiliation: Division of Cardiology, HuiQiao Medical Center, Nanfang Hospital, Southern Medical University, Guangzhou 510515, People's Republic of China.
authors.forename: Tiantian
authors.identifier: 0000-0002-1987-8978
authors.initials: T
authors.lastname: Luo
authors.affiliation: Division of Cardiology, HuiQiao Medical Center, Nanfang Hospital, Southern Medical University, Guangzhou 510515, People's Republic of China.
authors.forename: Jing
authors.initials: J
authors.lastname: Hu
authors.affiliation: Division of Cardiology, HuiQiao Medical Center, Nanfang Hospital, Southern Medical University, Guangzhou 510515, People's Republic of China.
authors.forename: Dan
authors.initials: D
authors.lastname: Xi
authors.affiliation: Division of Cardiology, HuiQiao Medical Center, Nanfang Hospital, Southern Medical University, Guangzhou 510515, People's Republic of China.
authors.forename: Haowei
authors.initials: H
authors.lastname: Xiong
authors.affiliation: Division of Cardiology, HuiQiao Medical Center, Nanfang Hospital, Southern Medical University, Guangzhou 510515, People's Republic of China.
authors.forename: Wenshuai
authors.initials: W
authors.lastname: He
authors.affiliation: Division of Cardiology, HuiQiao Medical Center, Nanfang Hospital, Southern Medical University, Guangzhou 510515, People's Republic of China.
authors.forename: Jichen
authors.identifier: 0000-0002-4447-7367
authors.initials: J
authors.lastname: Liu
authors.affiliation: Division of Cardiology, HuiQiao Medical Center, Nanfang Hospital, Southern Medical University, Guangzhou 510515, People's Republic of China.
authors.forename: Menghao
authors.initials: M
authors.lastname: Li
authors.affiliation: Division of Cardiology, HuiQiao Medical Center, Nanfang Hospital, Southern Medical University, Guangzhou 510515, People's Republic of China.
authors.forename: Hao
authors.initials: H
authors.lastname: Lu
authors.affiliation: Division of Cardiology, HuiQiao Medical Center, Nanfang Hospital, Southern Medical University, Guangzhou 510515, People's Republic of China.
authors.forename: Jinzhen
authors.initials: J
authors.lastname: Zhao
authors.affiliation: Division of Cardiology, HuiQiao Medical Center, Nanfang Hospital, Southern Medical University, Guangzhou 510515, People's Republic of China.
authors.forename: Wenyan
authors.initials: W
authors.lastname: Lai
authors.affiliation: Division of Cardiology, HuiQiao Medical Center, Nanfang Hospital, Southern Medical University, Guangzhou 510515, People's Republic of China guozhigang126@126.com.
authors.forename: Zhigang
authors.initials: Z
authors.lastname: Guo
mesh_terms: D064286:ATP Binding Cassette Transporter 1 / Q000235:genetics; D000070998:ATP Binding Cassette Transporter, Subfamily G, Member 1 / Q000235:genetics; D001692:Biological Transport / Q000187:drug effects; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D049109:Cell Proliferation / Q000187:drug effects; D002784:Cholesterol / Q000378:metabolism*; D016207:Cytokines / Q000276:immunology; D006360:Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D007249:Inflammation / Q000276:immunology; D015759:Ionomycin / Q000494:pharmacology; D019169:Jurkat Cells; D008213:Lymphocyte Activation; D019860:Lymphocyte Specific Protein Tyrosine Kinase p56(lck) / Q000235:genetics / Q000378:metabolism*; D020935:MAP Kinase Signaling System / Q000187:drug effects; D016328:NF-kappa B / Q000276:immunology; D047495:PPAR gamma / Q000235:genetics; D010766:Phosphorylation / Q000187:drug effects; D011743:Pyrimidines / Q000494:pharmacology; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism; D051122:Scavenger Receptors, Class B / Q000235:genetics; D015398:Signal Transduction / Q000187:drug effects; D013601:T-Lymphocytes / Q000187:drug effects / Q000276:immunology* / Q000378:metabolism*; D018834:Chaperonin 60; D024101:Mitochondrial Proteins
chemical_list: D064286:ATP Binding Cassette Transporter 1; D000070998:ATP Binding Cassette Transporter, Subfamily G, Member 1; D002118:Calcium; D002784:Cholesterol; D016207:Cytokines; D006360:Heat-Shock Proteins; D015759:Ionomycin; D019860:Lymphocyte Specific Protein Tyrosine Kinase p56(lck); D016328:NF-kappa B; D047495:PPAR gamma; D011743:Pyrimidines; D011948:Receptors, Antigen, T-Cell; D051122:Scavenger Receptors, Class B; C577836:ABCA1 protein, human; C419353:ABCG1 protein, human; C412373:AG 1879; C495124:SCARB1 protein, human; C060293:HSPD1 protein, human; D018834:Chaperonin 60; D024101:Mitochondrial Proteins