Mouse thymic stromal cell line 4 (MTSC4) is one of the stromal cell lines established in our laboratory. While losing the characteristics of epithelial cells, they express some surface markers shared with thymic dendr...Mouse thymic stromal cell line 4 (MTSC4) is one of the stromal cell lines established in our laboratory. While losing the characteristics of epithelial cells, they express some surface markers shared with thymic dendritic cells (TDCs). To further study the biological functions of these cells, we compared the capability of MTSC4 with TDCs in the induction of thymocyte apoptosis, using thymic reaggregation culture system. Apoptosis of thymocytes induced by MTSC4 and TDCs was measured by Annexin V and PI staining and analyzed by flow cytometry. We found that MTSC4 selectively augmented the apoptosis of CD4^+8^+ (DP) thymocytes. This effect was Fas/FasL independent and could not be blocked by antibodies to MHC class Ⅰ and class Ⅱ molecules. In addition, MTSC4 enhanced the apoptosis of DP thymocytes from different strains of mice, which implies that MTSC4-induced thymocyte apoptosis is not mediated by the TCR recognition of self peptide/MHC molecules. In contrast to MTSC4, thymocyte apoptosis induced by TDCs was MHC-restricted. Thus, MHC-independent fashion of stromal-DP thymocyte interaction may be one of the ways to induce thymocyte apoptosis in thymus. Our study has also shown that the interaction of MTSC4 stromal cells and thymocytes is required for the induction of thymocyte apoptosis.展开更多
The effect of thymic stromal lymphopoietin（TSLP） on macrophage-derived foam cell formation and the underlying mechanism were studied. Macrophages isolated from C57BL/6 mice were co-cultured in vitro with different c...The effect of thymic stromal lymphopoietin（TSLP） on macrophage-derived foam cell formation and the underlying mechanism were studied. Macrophages isolated from C57BL/6 mice were co-cultured in vitro with different concentrations of TSLP or TSLPR-antibody in the presence of oxidized low density lipoprotein（ox-LDL）. The effects of TSLP on macrophage-derived foam cell formation were observed by using oil red O staining and intracellular lipid determination. The expression levels of foam cell scavenger receptors（CD36 and SRA） as well as ABCA1 and TSLPR were detected by using RT-PCR and Western blotting. As compared with the control group, TSLP treatment significantly promoted lipid accumulation in macrophages, significantly increased protein expression of CD36 and TSLPR in a dose-dependent manner, and significantly reduced the expression of ABCA1 protein in a dose-dependent manner. No significant differences were noted between the TSLPR-antibody group and the control group. TSLP may down-regulate the expression of cholesterol efflux receptor ABCA1 and up-regulate scavenger receptor expression via the TSLPR signaling pathway, thereby promoting macrophage-derived foam cell formation.展开更多
It has been reported that atopic dermatitis (AD) and ulcerative colitis are related. However, the mechanism underlying this association has not been clarified. We therefore explored how AD induces ulcerative colitis. ...It has been reported that atopic dermatitis (AD) and ulcerative colitis are related. However, the mechanism underlying this association has not been clarified. We therefore explored how AD induces ulcerative colitis. We developed an AD mouse model (NC/Nga mice) with ulcerative colitis by administering dextran sodium sulfate (DSS) for five days. DSS-induced ulcerative colitis was deteriorated in our conventional AD mouse model compared with specific-pathogen-free (SPF) mice. The plasma levels of thymic stromal lymphopoietin (TSLP) and tumor necrosis factor-α increased the most in DSS-treated conventional mice. Furthermore, the expression of dendritic cells (DC), retinoid-related orphan receptor (ROR)γt (marker of T helper 17 cells [Th17]), interleukin (IL)-17, GATA binding protein 3 (GATA3) (marker of Th2), and IL-4 increased the most in the colon of the DSS-treated conventional mice compared with DSS-treated SPF mice. In addition, TSLP inhibitor (TSLP neutralizing antibody) did not exacerbate ulcerative colitis in DSS-treated conventional mice. These results indicate that TSLP/DC/Th2 and Th17 play major roles in the exacerbation of ulcerative colitis by AD.展开更多
基金This work was funded by grants from Major State Bascic Research Development Program of China(No.G1999053904)National Natural Science Foundation of China(No.30271200)Young Scentist Cooperation Research Fund(No.39928019).
文摘Mouse thymic stromal cell line 4 (MTSC4) is one of the stromal cell lines established in our laboratory. While losing the characteristics of epithelial cells, they express some surface markers shared with thymic dendritic cells (TDCs). To further study the biological functions of these cells, we compared the capability of MTSC4 with TDCs in the induction of thymocyte apoptosis, using thymic reaggregation culture system. Apoptosis of thymocytes induced by MTSC4 and TDCs was measured by Annexin V and PI staining and analyzed by flow cytometry. We found that MTSC4 selectively augmented the apoptosis of CD4^+8^+ (DP) thymocytes. This effect was Fas/FasL independent and could not be blocked by antibodies to MHC class Ⅰ and class Ⅱ molecules. In addition, MTSC4 enhanced the apoptosis of DP thymocytes from different strains of mice, which implies that MTSC4-induced thymocyte apoptosis is not mediated by the TCR recognition of self peptide/MHC molecules. In contrast to MTSC4, thymocyte apoptosis induced by TDCs was MHC-restricted. Thus, MHC-independent fashion of stromal-DP thymocyte interaction may be one of the ways to induce thymocyte apoptosis in thymus. Our study has also shown that the interaction of MTSC4 stromal cells and thymocytes is required for the induction of thymocyte apoptosis.
基金supported by the National Natural Science Foundation of China(No.81170258)
文摘The effect of thymic stromal lymphopoietin（TSLP） on macrophage-derived foam cell formation and the underlying mechanism were studied. Macrophages isolated from C57BL/6 mice were co-cultured in vitro with different concentrations of TSLP or TSLPR-antibody in the presence of oxidized low density lipoprotein（ox-LDL）. The effects of TSLP on macrophage-derived foam cell formation were observed by using oil red O staining and intracellular lipid determination. The expression levels of foam cell scavenger receptors（CD36 and SRA） as well as ABCA1 and TSLPR were detected by using RT-PCR and Western blotting. As compared with the control group, TSLP treatment significantly promoted lipid accumulation in macrophages, significantly increased protein expression of CD36 and TSLPR in a dose-dependent manner, and significantly reduced the expression of ABCA1 protein in a dose-dependent manner. No significant differences were noted between the TSLPR-antibody group and the control group. TSLP may down-regulate the expression of cholesterol efflux receptor ABCA1 and up-regulate scavenger receptor expression via the TSLPR signaling pathway, thereby promoting macrophage-derived foam cell formation.
文摘It has been reported that atopic dermatitis (AD) and ulcerative colitis are related. However, the mechanism underlying this association has not been clarified. We therefore explored how AD induces ulcerative colitis. We developed an AD mouse model (NC/Nga mice) with ulcerative colitis by administering dextran sodium sulfate (DSS) for five days. DSS-induced ulcerative colitis was deteriorated in our conventional AD mouse model compared with specific-pathogen-free (SPF) mice. The plasma levels of thymic stromal lymphopoietin (TSLP) and tumor necrosis factor-α increased the most in DSS-treated conventional mice. Furthermore, the expression of dendritic cells (DC), retinoid-related orphan receptor (ROR)γt (marker of T helper 17 cells [Th17]), interleukin (IL)-17, GATA binding protein 3 (GATA3) (marker of Th2), and IL-4 increased the most in the colon of the DSS-treated conventional mice compared with DSS-treated SPF mice. In addition, TSLP inhibitor (TSLP neutralizing antibody) did not exacerbate ulcerative colitis in DSS-treated conventional mice. These results indicate that TSLP/DC/Th2 and Th17 play major roles in the exacerbation of ulcerative colitis by AD.
