RESUMO
CD47 is a transmembrane protein widely expressed on cell surface, which is considered as a key molecule for immune escape. With an increasing number of related studies, the role of CD47 and its ligands in immunomodulatory effects has been gradually understood. Recent studies have investigated the role of CD47 in ischemia-reperfusion injury of allogenetic kidney transplantation, rejection and xenotransplantation. Nevertheless, the specific role and the key mechanism remain elusive. In this article, the structure and function of CD47, common CD47 ligands, the relationship between CD47 and kidney transplantation, and the application of CD47 in kidney transplantation were reviewed, the latest research progress of CD47 in kidney transplantation was summarized, and the limitations of current research and subsequent research direction were analyzed, aiming to provide reference for subsequent application of CD47 in allogeneic and kidney xenotransplantation.
RESUMO
BACKGROUND@#Lung cancer has a high incidence and mortality rate, but the treatment of lung cancer still lacks low toxicity and efficient anti-tumor drugs. Polysaccharide from radix tetrastigme has development value in anti-tumor treatment methods. This study was to observe the effect of polysaccharide from radix tetrastigme on immune response of Lewis lung cancer mice and explore its molecular mechanism.@*METHODS@#Lewis lung cancer mouse models were established and randomly grouped. The spleen polypeptide group was intragastric with 50 mg/kg spleen polypeptide, and the radix tetrastigme polysaccharide low, medium and high dose groups were intragastric with 62.5, 125 and 250 mg/kg radix tetrastigme polysaccharide, respectively, and the model group and the control group were intragastric with equivolume normal saline. Tumor formation and metastasis were compared. Haematoxylin-eosin (HE) staining was used to observe the pathological changes of tumor cells. Macrophage phagocytosis, apoptosis, M1/M2 polarization, T cell subsets and cytokine levels in peripheral blood were detected by flow cytometry. The proliferation activity of macrophages was detected by methyl thiazolyldiphenyl tetrazolium (MTT) assay. Dendritic cell (DC) antigen presenting function was detected by chlorophenol red-β-D-galactopyranoside (CPRG) method. Tumor tissue differentiation antigen cluster 47 (CD47) mRNA and protein expression and macrophage signal regulatory protein α (SIRRP α) expression were detected by real time quantitative polymerase chain reaction (RT-qPCR) and Western blot (WB).@*RESULTS@#The tumor inhibition rates and anti-metastasis rates in the 3-dose radix tetrastigme polysaccharide group and the spleen polypeptide group were higher than those in the model group, and the pathological injury of tumor tissue were severer, and the positive rate of phagocytosis of ink by macrophages and the efficiency of phagocytosis of tumor cells were increased; the apoptosis rate of macrophages was decreased; the proliferation activity of macrophages, polarization ratio of macrophages to M1 type, DC antigen presenting ability, CD4+, CD4+/CD8+ levels were increased; the level of serum tumor necrosis factor α (TNF-α), interleukin-1β (IL-1β), and the expression of tumor tissue CD47, macrophage SH2-containing protein tyrosine phosphatase 1 (SHP-1), SH2-containing protein tyrosine phosphatase 2 (SHP-2), and phosphorylation signal regulatory protein α (p-SIRPα) were decreased, and the differences were statistically significant (P<0.05). There were no significant differences in the above indexes between low-dose radix tetrastigme polysaccharide group and spleen polypeptide group (P>0.05), and the effects of radix tetrastigme polysaccharide were dose-dependent.@*CONCLUSIONS@#Radix tetrastigme polysaccharide can inhibit tumor growth, metastasis and immune response in Lewis lung cancer mice, and its mechanism may be related to inhibiting SIRP/CD47 signaling pathway.
Assuntos
Camundongos , Animais , Antígeno CD47/genética , Neoplasias Pulmonares/tratamento farmacológico , Citocinas/genética , Polissacarídeos/farmacologia , Imunidade , Proteínas Tirosina FosfatasesRESUMO
Objective To investigate the dynamic expression of cluster of differentiation 47 (CD47) and its ligands signaling regulatory protein α (SIRPα) and thrombospondin-1 (TSP-1) in mice infected with Toxoplasma gondii in the second and third trimesters.. Methods C57BL/6J mice (6 to 8 weeks old) were used for modeling T. gondii infection in the first trimester, and the pregnant mice were randomly divided into the normal control and infection groups, of 10 mice in each group. Pregnant mice in the infection group were intraperitoneally injected with 150 T. gondii tachyzoites on gestational day (Gd) 6.5, while pregnant mice in the normal control group were intraperitoneally injected with the same volume of physiological saline at the same time. The uterine and placental specimens were collected from all pregnant mice on Gd12.5 and Gd18.5, and the pregnant outcomes were recorded. The pathological damages of mouse uterine and placental specimens were observed using hematoxylin-eosin (HE) staining on Gd12.5 and Gd18.5. The relative expression of CD47, SIRPα, TSP-1, surface antigen 1 (SAG1), interferon-γ (IFN-γ), interleukin-2 (IL-2), IL-4 and IL-13 mRNA was quantified in mouse uterine and placental specimens using real-time fluorescence quantitative PCR (qPCR) assay, and the CD47, SIRPα, TSP-1 expression was determined in mouse uterine and placental specimens using immunohistochemical staining. Results As compared with those in the normal control group, the pregnant mice in the infection group showed back arching, bristling, trembling and listlessness during pregnancy, and several mice presented virginal bleeding and abortion. Pathological examinations showed inflammatory cell infiltration, congestion and necrosis in uterine and placental specimens of pregnant mice in the infection group, a higher abortion rate of pregnant mice was seen in the infection group than in the normal control group on Gd12.5 (χ2 = 20.405, P < 0.001) and Gd18.5 (χ2 = 28.644, P < 0.001). qPCR assay showed significant differences in the expression of CD47, SIRPα, TSP-1, SAG1, INF-γ, IL-2, IL-4 and IL-13 genes in mouse placental specimens between the normal control and infection groups on Gd12.5 and Gd18.5 [F′ (F) = 37.511, 29.337, 97.343, 53.755, 67.188, 21.145, 8.658 and 13.930, all P values < 0.001]. Higher CD47, SIRPα and TSP-1 gene expression was quantified in mouse placental specimens in the infection group than in the normal control group on Gd12.5 (all P values < 0.01), and lower CD47, SIRPα and TSP-1 gene expression was quantified in the infection group than in the normal control group on Gd18.5 (all P values < 0.001), while higher SAG1 gene expression was detected in placental specimens of pregnant mice in the infection group than in the normal control group on Gd12.5 and Gd18.5 (both P values < 0.01). In addition, higher INF-γ and IL-2 expression and lower IL-4 and IL-13 expression was detected in mouse placental specimens in the infection group than in the normal control group on Gd12.5 and Gd18.5 (all P values < 0.001), and there were significant differences in the CD47, SIRPα, TSP-1, SAG1, INF-γ, IL-2, IL-4 and IL-13 gene expression in uterine specimens of pregnant mice between the normal control and infection groups on Gd12.5 and Gd18.5 [H(F′ and F) = 14.951, 25.977, 18.711, 48.595, 39.318, 14.248 and 15.468, all P values < 0.01], and higher CD47 and TSP-1 expression was detected in mouse uterine specimens in the infection group than in the control group on Gd12.5 and Gd18.5 (all P values < 0.01); however, no significant difference was found in the SIRPα expression (P > 0.05). Higher SAG1 expression was detected in uterine specimens of pregnant mice in the infection group than in the normal control group on Gd12.5 and Gd18.5 (both P values < 0.01), and higher INF-γ and IL-2 gene expression and lower IL-4 and IL-13 gene expression was found in the placental specimens of pregnant mice in the infection group than in the normal control group on Gd12.5 and Gd18.5 (all P values < 0.001). Spearman correlation analysis showed that the CD47 gene expression correlated positively with IFN-γ (rs = 0.735, P < 0.05) and IL-2 (rs = 0.655, P < 0.05) and negatively with IL-4 (rs = −0.689, P < 0.05) and IL-13 expression (rs = −0.795, P < 0.05) in the placental specimens of pregnant mice in the infection group on Gd12.5, and the CD47 gene expression correlated negatively with IFN-γ (rs = −0.745, P < 0.05) and IL-2 expression (rs = −0.816, P < 0.05) and positively with IL-4 (rs = 0.704, P < 0.05) and IL-13 (rs = 0.802, P < 0.05) in the placental specimens of pregnant mice in the infection group on Gd18.5. Immunohistochemical staining showed mild CD47, SIRPα and TSP-1 expression in uterine and placental specimens of pregnant mice in the normal control group on Gd12.5 and Gd18.5, strong CD47, SIRPα and TSP-1 expression in the placental specimens of pregnant mice in the infection group on Gd12.5 and strong CD47 and TSP-1 expression in the uterine specimens of pregnant mice in the infection group on Gd12.5. Conclusions T. gondii infection in the first trimester may cause abnormal expression of CD47 and its ligands SIRPα and TSP-1 in the maternal-fetal interface of pregnant mice in the second and third trimesters, which may be associated with the immune escape of T. gondii at the maternal-fetal interface.
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Objective To investigate the effect of human CD47 (hCD47) in inducing the immune tolerance of human macrophages to porcine endothelial cells. Methods The porcine iliac endothelial cell (PIEC) transfected with pCDH-hCD47-FLAG plasmid was assigned into the pCDH-hCD47 group, PIEC transfected with pCDH-FLAG empty vector plasmid was assigned into the pCDH group, PIEC transfected with hCD47-dN was assigned into the pCDH-hCD47-dN group and human umbilical vein endothelial cell (HUVEC) was assigned into the positive control group. The cells were co-cultured with human macrophages to detect and analyze the phosphorylation of signal regulatory protein α (SIRPα) and the killing effect of human macrophages on PIEC. Furthermore, porcine arteriae endothelial cell (PAEC) was isolated from GT－/－ and GT－/－/ hCD 47 gene editing pigs to analyze the phosphorylation of SIRPα and the killing effect of human macrophages on PAEC. Results The pCDH group cells could not induce the phosphorylation of SIRPα, whereas the pCDH-hCD47 group cells could activate the phosphorylation of SIRPα after 10 min co-culture with human macrophages, and the degree of phosphorylation of SIRPα was increased with the prolongation of the co-culture time. The pCDH-hCD47-dN group cells failed to activate the phosphorylation of SIRPα. Human macrophages exerted significant effect on killing the pCDH group cells. The pCDH-hCD47 group cells could evidently inhibit the killing effect of human macrophages (P < 0.05), whereas the pCDH-hCD47-dN cells failed to suppress the killing effect of human macrophages. GT－/－-PAEC could not activate the phosphorylation of SIRPα after co-culture with human macrophages. However, GT－/－/hCD47-PAEC significantly activated the phosphorylation of SIRPα after co-culture with human macrophages. Human macrophages exerted significant killing effect on GT－/－-PAEC, and GT－/－/hCD47-PAEC could obviously inhibit the killing effect of human macrophages (P < 0.05). Conclusions The expression of hCD47 in the porcine endothelial cells can inhibit the killing effect of human macrophages on endothelial cells by activating the phosphorylation of SIRPα.
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To prepare a monoclonal antibody against human SIRPα using synthetic peptide, and to use it for immune test to assess its efficacy. Methods: The synthetic peptide of SIRPα was linked with KLH and the product was used as antigen for immunization of BALB/c mice. The mAb anti-SIRPα was obtained by hybridoma technique. The produced mAb was used for flow cytometry, Western blotting analysis and immunohistochemistry assay. Cytokines secreted by PMA-treated THP-1 cells were tested by antibody arrays after exposure to the obtained mAb, and the levels of TNF-α and IL-6 were assayed by ELISA. Results: The mAb secreting hybridoma clone was successfully obtained and it had a satisfactory efficacy when used for flow cytometry, Western blotting analysis and immunohistochemistry assay. Compared with negative control and isotype control, the prepared mAb can stimulate TNF-α and IL-6 secretion in PMA-treated THP-1 cells. Conclusion: We have successfully prepared the mAb against SIRPo using synthetic peptide.