RESUMO
TNF-related apoptosis-inducing ligand (TRAIL) and FasL can participate in cell mediated cytotoxicity via their death domain-mediated apoptotic signaling in the host-versus-graft disease occurred after renal transplantation. However, the effect of Cyclosporin A (CsA) commonly used as a drug to prevent and to treat renal transplant rejection, on these molecules have not been fully determined. In the present study, we found that with CsA administration, the expression of TRAIL and FasL predominantly on NK cells from renal transplantation patients was increased at day 5 after operation and went down to normal level on day 13. While, the levels of soluble TRAIL (sTRAIL) and sFasL in the serum increased within 25 days and went down to normal level three month later. In addition, we showed that a remarkable increase of TRAIL and FasL expression both on the surface of activated lymphocytes especially on NK cells and in the supernatants generated from mixed lymphocytes culture (MLC). Furthermore, the enhancement of these two molecules was greatly decreased by adding 500 ng/mL CsA at the beginning of MLC. We conclude that CsA may inhibit the transplant rejection partially by down-regulating the expression of TRAIL and FasL on NK cells.
Assuntos
Ciclosporina/administração & dosagem , Proteína Ligante Fas/metabolismo , Rejeição de Enxerto/prevenção & controle , Transplante de Rim , Células Matadoras Naturais/efeitos dos fármacos , Complicações Pós-Operatórias/prevenção & controle , Ligante Indutor de Apoptose Relacionado a TNF/metabolismo , Adolescente , Adulto , Células Cultivadas , Citotoxicidade Imunológica/efeitos dos fármacos , Regulação para Baixo/efeitos dos fármacos , Proteína Ligante Fas/genética , Feminino , Rejeição de Enxerto/etiologia , Humanos , Células Matadoras Naturais/imunologia , Teste de Cultura Mista de Linfócitos , Masculino , Pessoa de Meia-Idade , Ligante Indutor de Apoptose Relacionado a TNF/genética , Adulto JovemRESUMO
CD226 is one of the main activating receptors on natural killer cells, and it can induce cytotoxicity to target cells through interaction with its ligands CD155 or CD112. CD226 is also involved in T cell differentiation, activation, and cytotoxicity. The expression of CD226 on natural killer cells and T cells can be regulated by cytokines and chemical stimuli; however, the mechanism of the regulation of the CD226 gene is still unknown. In this study, we have identified two promoters in the human CD226 gene named P1 and P2, which are located at -810 to -287 bp and +33 to +213 bp, respectively, and a negative regulation element between P1 and P2. Both P1 and P2 can be regulated by phorbol ester (12-O-tetradecanoylphorbol-13-acetate) and calcium ionophore (A23187). Bioinformatics analysis shows that, within this CD226 gene region, there are putative binding sites for transcription factors AP-1, Sp1, PEA3, and Ets-1. We have found that transcription factor activating protein-1 (AP-1) can up-regulate CD226 promoters P1 and P2 in human hepatocarcinoma cells, a hepatocarcinoma cell line with low expression of endogenous AP-1 and Ets-1. Interestingly, the transcription factor Ets-1 promotes AP-1-induced P2 activity but inhibits AP-1-induced P1 activity for which a 10-bp AP-1/Ets-1 composite site (CCTTCCTTCC) in P1 may be responsible.
Assuntos
Antígenos de Diferenciação de Linfócitos T/genética , Antígenos de Diferenciação de Linfócitos T/fisiologia , Regulação Neoplásica da Expressão Gênica , Regiões Promotoras Genéticas , Proteína Proto-Oncogênica c-ets-1/metabolismo , Fator de Transcrição AP-1/metabolismo , Sequência de Bases , Sítios de Ligação , Fragmentação do DNA , Humanos , Células Jurkat , Células Matadoras Naturais/metabolismo , Modelos Biológicos , Dados de Sequência Molecular , Ligação ProteicaRESUMO
The expression of the apoptosis-inducing ligands, TNF-alpha, FasL and TRAIL on peripheral blood mononuclear cells (PBMC) and the levels of their soluble form (TNF-alpha, sFasL and sTRAIL) in plasma from 40 hemorrhagic fever with renal syndrome (HFRS) patients as well as 26 healthy blood donors were determined by flow cytometry (FCM) analysis and sandwich ELISA, respectively. The status of Th1, Th2, Tc1 and Tc2 subsets in PBMC was evaluated by intracellular cytokine staining and FCM. Compared to controls, the expression of membrane bound FasL and TRAIL was up-regulated on surface of PBMC isolated from the HFRS patients, particularly on CD8+ T lymphocytes. The levels of TNF-alpha, sFasL and sTRAIL in plasma from the HFRS patients in the acute phase increase 4.7-fold, 6.0-fold and 1.8-fold, respectively, over those from the healthy donors. The percentage of Th1, Tc1 and Tc2 subsets in PBMC from the patients also increased significantly compared with those from healthy donors. These results indicate that dynamic changes occurred in both the membrane bound and soluble forms of apoptosis-inducing ligands (FasL, TRAIL and TNF-alpha) and proportions of Th1 and CTL in HFRS patients increased. Both factors may play an important role in the etiology of Hantaan virus infection in humans.