title: Polycomb chromobox (Cbx) 7 modulates activation-induced CD4+ T cell apoptosis.
abstract: CD4(+) T cell polarization plays a critical role in a number of immune disorders; the pathogenesis is unclear. Chromobox homolog 7 (Cbx7) is involved in the gene transcription of several cell types. This study aims to investigate the mechanism by which Cbx7 modulates the CD4(+) T cell polarization. Expression of Cbx7 was assessed by quantitative RT-PCR and Western blotting. Apoptosis of CD4(+) T cell was analyzed by flow cytometry. The FasL promoter methylation was evaluated by the methylation specific PCR. The results showed that CD4(+) CD25(-) T cells express Cbx7 that was increased significantly after activation by exposing to anti-CD3/CD28 Ab, but suppressed by exposing to specific antigens. More apoptotic cells were detected in CD4(+) T cells with the Cbx7 gene knockdown. Exposure to insulin-like growth factor-1 up regulated the expression of Cbx7 in CD4(+) T cells. After antigen-specific TCR activation, Cbx7-deficient CD4(+) T cells expressed more FasL and showed the FasL gene promoter hyper demethylation than wild CD4(+) T cells. In addition, CD4(+) T cells with overexpression of Cbx7 showed lower levels of FasL gene promoter demethylation. We conclude that CD4(+) T cells express Cbx7; the latter prevents FasL expression and the activation-induced CD4(+) T cell apoptosis.
authors.affiliation: Center Clinical Laboratory, Children's Hospital of Fudan University, Shanghai 201102, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Li
authors.affiliation: Laboratory Medicine, Kunming Medical University, Kunming 650101, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Li
authors.affiliation: Cardiovascular Center, Children's Hospital of Fudan University, Shanghai 201102, China.
authors.forename: Yinyin
authors.initials: Y
authors.lastname: Cao
authors.affiliation: Center Clinical Laboratory, Children's Hospital of Fudan University, Shanghai 201102, China.
authors.forename: Meifen
authors.initials: M
authors.lastname: Yuan
authors.affiliation: Center Clinical Laboratory, Children's Hospital of Fudan University, Shanghai 201102, China.
authors.forename: Zhengfeng
authors.initials: Z
authors.lastname: Gao
authors.affiliation: Center Clinical Laboratory, Children's Hospital of Fudan University, Shanghai 201102, China.
authors.forename: Xuemei
authors.initials: X
authors.lastname: Guo
authors.affiliation: Center Clinical Laboratory, Children's Hospital of Fudan University, Shanghai 201102, China.
authors.forename: Fenhua
authors.initials: F
authors.lastname: Zhu
authors.affiliation: Department of Otolaryngology, Affiliated Eye and ENT Hospital of Fudan University, Shanghai 200031, China.
authors.forename: Yunfeng
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Center Clinical Laboratory, Children's Hospital of Fudan University, Shanghai 201102, China. Electronic address: xujinngg@126.com.
authors.forename: Jin
authors.initials: J
authors.lastname: Xu
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology / Q000378:metabolism*; D019175:DNA Methylation / Q000502:physiology; D053222:Fas Ligand Protein / Q000096:biosynthesis* / Q000235:genetics / Q000276:immunology; D005786:Gene Expression Regulation / Q000502:physiology*; D055785:Gene Knockdown Techniques; D007334:Insulin-Like Growth Factor I / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D008213:Lymphocyte Activation / Q000502:physiology*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D063150:Polycomb Repressive Complex 1 / Q000096:biosynthesis* / Q000235:genetics / Q000276:immunology; D011401:Promoter Regions, Genetic; D011948:Receptors, Antigen, T-Cell / Q000235:genetics / Q000276:immunology / Q000378:metabolism / Q000502:physiology
chemical_list: C519505:Cbx7 protein, mouse; D053222:Fas Ligand Protein; C505658:Fasl protein, mouse; D011948:Receptors, Antigen, T-Cell; D007334:Insulin-Like Growth Factor I; D063150:Polycomb Repressive Complex 1
keywords: Apoptosis; Chromobox homolog 7; Fas ligand; Methylation; T lymphocyte