ABSTRACT
Tumor necrosis factor receptor-related 2 (TR2, HVEM or TNFRSF-14) plays an important role in immune responses, however, the mechanisms regulating its expression are unclear. To understand the control of TR2 gene expression, we studied the upstream region of the gene. Gel supershift assays revealed inducible binding of nuclear factor of activated T cells (NFAT) to a putative NFAT site within the TR2 promoter. Furthermore, cotransfection of a dominant negative NFAT construct, or siRNA for NFAT, resulted in increased expression of a TR2 reporter gene. Our findings demonstrate that NFAT negatively regulates TR2 expression in activated T cells.
Subject(s)
Animals , Mice , Base Sequence , CD4-Positive T-Lymphocytes/metabolism , Cells, Cultured , Down-Regulation , Mice, Inbred C57BL , Molecular Sequence Data , NFATC Transcription Factors/physiology , Receptors, Tumor Necrosis Factor, Member 14/biosynthesis , T-Lymphocytes/metabolismABSTRACT
4-1BB, a member of the tumor necrosis factor receptor (TNFR) superfamily, is a major costimulatory receptor that is rapidly expressed on the surface of CD4+ and CD8+ T cells after antigen- or mitogen-induced activation. The interaction of 4-1BB with 4-1BBL regulates immunity and promotes the survival and expansion of activated T cells. In this study, the expression of 4-1BB and 4-1BBL was examined during regeneration of the murine thymus following acute cyclophosphamide-induced involution. Four-color flow cytometry showed that 4-1BB and 4-1BBL were present in the normal thymus and were preferentially expressed in the regenerating thymus, mainly in CD4+CD8+ double-positive (DP) thymocytes. Furthermore, the CD4loCD8lo, CD4+CD8lo and CD4loCD8+ thymocyte subsets, representing stages of thymocyte differentiation intermediate between DP and single-positive (SP) thymocytes, also expressed 4-1BB and 4-1BBL during thymus regeneration but to a lesser degree. Interestingly, the 4-1BB and 4-1BBL positive cells among the CD4+CD8+ DP thymocytes present during thymus regeneration were TCR(hi) and CD69+ unlike the corresponding controls. Moreover, the 4-1BB and 4-1BBL positive cells among the intermediate subsets present during thymus regeneration also exhibited TCRhi/int and CD69+/int phenotypes, indicating that 4-1BB and 4-1BBL are predominantly expressed by the positively selected population of the CD4+CD8+ DP and the intermediate thymocytes during thymus regeneration. RT-PCR and Western blot analyses confirmed the presence and elevated levels of 4-1BB and 4-1BBL mRNA and protein in thymocytes during thymus regeneration. We also found that the interaction of 4-1BB with 4-1BBL promoted thymocyte adhesion to thymic epithelial cells. Our results suggest that 4-1BB and 4-1BBL participate in T lymphopoiesis associated with positive selection during recovery from acute thymic involution.
Subject(s)
Animals , Male , Mice , 4-1BB Ligand/genetics , Tumor Necrosis Factor Receptor Superfamily, Member 9/genetics , CD4-Positive T-Lymphocytes/cytology , CD8-Positive T-Lymphocytes/cytology , Cell Adhesion , Cell Differentiation , Cell Line , Cells, Cultured , Cyclophosphamide/pharmacology , Epithelial Cells/cytology , Gene Expression Regulation , Immunosuppressive Agents/pharmacology , Mice, Inbred C57BL , RNA, Messenger/genetics , Regeneration , T-Lymphocytes/cytology , Thymus Gland/cytologyABSTRACT
A C6 beta-chemokine, CKbeta8-1, suppressed the colony formation of CD34 + cells of human cord blood (CB). Molecular mechanisms involved in CKbeta8-1-medicated suppression of colony formation of CD34 + cells are not known. To address this issue, the level of various G1/S cell cycle regulating proteins in CKbeta8-1-treated CD34 + cells were compared with those in untreated CD34 + cells. CKbeta8-1 did not significantly alter the expression of the G1/S cycle regulation proteins (cyclin D1, D3, and E), CDK inhibitor (p27and Rb), and other cell proliferation regulation protein (p53) in CB CD34 + cells. Here we describe an in vitro system in which CB CD34 + cells were committed to a multipotent progenitor lineage of colony forming units-granulocyte/macrophage (CFU-GM) by a simple combination of recombinant human (rh) GM-CSF and rhIL-3. In this culture system, we found that cyclin E protein appeared later and disappeared faster in the CKbeta8-1-treated cells than in the control cells during CFU-GM lineage development. These findings suggested that cyclin E may play a role in suppressing the colony formation of CFU-GM by CKbeta8-1.
Subject(s)
Humans , Antigens, CD34/metabolism , Cell Cycle Proteins/metabolism , Cell Lineage , Cells, Cultured , Chemokines, CC/pharmacology , Cyclin E/metabolism , Fetal Blood/cytology , G1 Phase/drug effects , Gene Expression Regulation/drug effects , Granulocytes/cytology , Growth Substances/pharmacology , Macrophages/cytology , Stem Cells/cytologyABSTRACT
Glucocorticoid-induced TNF receptor (GITR) was a new member of the TNF/nerve growth factor receptor (TNFR/ NGFR) family and induced in murine T cells by dexamathasone. Recombinant soluble GITR (sGITR) induced an inflammation in peritoneal membrane and changes in spleen after i.p. injection of 3 mg/kg in C57BL/6 mice. Spleen was enlarged and percentage of neutrophils and monocytes were increased. The area of red pulp in spleen was increased, while that of white pulp was decreased after GITR injection. The thickening of membrane and neutrophil infiltration was observed in peritoneal membrane with increased myeloperoxidase activity. At later time, neutrophil infiltration moved to inside the tissue with tissue damage. GITR ligand and GITR were expressed constitutively on the surface of spleen cells and cells from peritoneal fluid. In contrast, no significant change in the spleen and in peritoneal membrane was observed in mice treated with LPS. GITR may play a role in body's inflammatory processes.
Subject(s)
Animals , Male , Mice , Carrier Proteins/metabolism , Flow Cytometry , Inflammation/chemically induced , Injections , Mice, Inbred C57BL , Receptors, Nerve Growth Factor/metabolism , Receptors, Tumor Necrosis Factor/metabolism , Solubility , Spleen/metabolismABSTRACT
BACKGROUND: The costimulatory molecule 4-1BB, a member of nerve growth factor receptor/tumor necrosis factor (NGFR/TNFR) super family, is involved in cell survival and death. METHODS: In this study, female C57BL/6 (H-2(b)) mice were used as a recipient, and DBA/2 (H-2(d)) as a donor to assess a mixed lymphocyte reaction (MLR) and CTL response in vitro, and skin graft survival. IL-2, IFN level was measured by ELISA. RESULTS: Mixed lymphocyte reaction (MLR) analysis showed that 4-1BB- deficient responder cells showed enhanced cellular proliferation over littermate controls. In contrast, IL-2 production was diminished only in 4-1BB knockout cultures. The IFN expression, on the other hand, was comparable between the groups. When female C57BL/6 (H-2(b)) mice were grafted with the trunk skin of DBA/2 (H-2d) mice, the in vivo tissue destruction of 4-1BB-deficient mice was not distinct from the normal littermates. CONCLUSION: These data suggest that 4-1BB is critical for the induction of alloreactive responses in vitro but 4-1BB alone could not change the course of skin rejection in vivo.
Subject(s)
Animals , Female , Humans , Mice , Allografts , Cell Proliferation , Cell Survival , Enzyme-Linked Immunosorbent Assay , Graft Survival , Hand , Interleukin-2 , Lymphocyte Culture Test, Mixed , Necrosis , Nerve Growth Factor , Skin , Tissue Donors , TransplantsABSTRACT
BACKGROUND: The costimulatory molecule 4-1BB, a member of nerve growth factor receptor/tumor necrosis factor (NGFR/TNFR) super family, is involved in cell survival and death. METHODS: In this study, female C57BL/6 (H-2(b)) mice were used as a recipient, and DBA/2 (H-2(d)) as a donor to assess a mixed lymphocyte reaction (MLR) and CTL response in vitro, and skin graft survival. IL-2, IFN level was measured by ELISA. RESULTS: Mixed lymphocyte reaction (MLR) analysis showed that 4-1BB- deficient responder cells showed enhanced cellular proliferation over littermate controls. In contrast, IL-2 production was diminished only in 4-1BB knockout cultures. The IFN expression, on the other hand, was comparable between the groups. When female C57BL/6 (H-2(b)) mice were grafted with the trunk skin of DBA/2 (H-2d) mice, the in vivo tissue destruction of 4-1BB-deficient mice was not distinct from the normal littermates. CONCLUSION: These data suggest that 4-1BB is critical for the induction of alloreactive responses in vitro but 4-1BB alone could not change the course of skin rejection in vivo.