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
Apoptosis of thymocytes is involved in the negative selection of thymus, but it remains unclear how the cell death of thymocytes is regulated by the thymic stromal cells. By using immunohistochemistry, TdT mediated dU...Apoptosis of thymocytes is involved in the negative selection of thymus, but it remains unclear how the cell death of thymocytes is regulated by the thymic stromal cells. By using immunohistochemistry, TdT mediated dUTP nick end labeling (TUNEL) and flow cytometry methods, it was found that Fas ligand was expressed in the thymic medulla and a mouse thymic medullary type dendritic cell line (MTSC4). The DNA fragmentation and TUNEL positive staining of thymocytes were detected in 6 h of cocultures with MTSC4. 97% of the thymocytes which bound to MTSC4 were Fas antigen positive cells. The DNA fragmentation of thymocytes induced by MTSC4 was inhibited by the addition of 20 mmol/L N acetyl galactosamin monosaccharide and the pretreatment of a monoclonal antibody (PF 18 3) which recognized a putative antigen on MTSC4. These results suggested that the mechanisms of induction of cell death by stromal cells may include the interactions of multiple cell surface molecules, in addition to the Fas/Fas ligand system.展开更多
The mechanism of chemotherapeutic drug-induced apoptosis in leukaemic cells was studied to further investigate whether Fas/FasL system was involved in apoptosis induced by chemotherapeutic drugs and assess their effec...The mechanism of chemotherapeutic drug-induced apoptosis in leukaemic cells was studied to further investigate whether Fas/FasL system was involved in apoptosis induced by chemotherapeutic drugs and assess their effects when used in combination with soluble FasL (sFasL). The expression of Fas on human leukaemic cell lines K562, HL-60 and U937 treated with daunorubicin (DNR) or cytosine arabinoside (Ara-C) was detected by using flow cytometry. The activities of sFasL, DNR and Ara-C inducing apoptosis of leukaemic cells, in the absence or presence of neutralizing anti-Fas IgG antibody, were detected by using flow cytometry and TUNEL. The results showed that flow cytometric profiles of K562, HL-60 and U937 cells treated with DNR or Ara-C failed to show any significant increase in Fas expression over 18 h (P>0.05). Anti-Fas monoclonal antibody (IgG) could not block the apoptosis in leukaemic cells induced by DNR or Ara-C, but could block the apoptosis induced by sFasL. A role of sFasL in a cytotoxic synergistic effect when used in combination with chemotherapeutic drugs was revealed. It was concluded that chemotherapeutic drug-induced apoptosis in human leukaemic cells (UG37, HL-60) is independent of the Fas/FasL system, but combination of sFasL and drug treatment produces a synergistic cytotoxic effect on human luekaemic cells.展开更多
Purpose: To study the molecular mechanism of trabecular meshwork cells apoptosis induced by dexamethasone and the protection of pilocarpine.Methods: Determining mRNA expression with reverse transcription-polymerase ch...Purpose: To study the molecular mechanism of trabecular meshwork cells apoptosis induced by dexamethasone and the protection of pilocarpine.Methods: Determining mRNA expression with reverse transcription-polymerase chain reaction (RT-PCR), protein expression with Western blots and the percentage of apoptotic cells with fluorescent microscopy.Results: Dexamethasone up-regulated Fas proteins and affected Bax, caspase-8 and caspase-9 proteins in an action of first decrease then increase. Pre-treatment with pilocarpine decreased the four proteins expression, which were increased by dexamethasone. Pilocarpine self could decrease pro-apoptotic factors Bax, caspase-8 and caspase-9 proteins expression.Conclusion: Fas/FasL pathway participated in apoptotic process induced by dexamethasone in trabecular meshwork cells and the process was probably related with both caspase-8 and caspase-9 pathways. Pilocarpine protected the cells against apoptosis through down-regulating Fas, Bax, caspase-8 and caspase-9 proteins expression.展开更多
To investigate the value of apoptosis of the allo antigen specific T cells induced by Fas/FasL pathway in preventing graft versus host disease (GVHD), the CD34 + cells transfected with FasL or not, used as stimul...To investigate the value of apoptosis of the allo antigen specific T cells induced by Fas/FasL pathway in preventing graft versus host disease (GVHD), the CD34 + cells transfected with FasL or not, used as stimulus cells, were mixed with allo antigen specific T lymphocytes in presence or absence of IFN γand IL 2. After 5 days, apoptosis of T cells was detected by TdT nick end mediated dUTP labeling (TUNEL) and flow cytometry (FCM). The affects of these two cytokines on CD34 + cells in the graft were also compared. The ratio of apoptosis of T cells was 12.1±1.5 % when CD34 + cells transfected with FasL was used as stimulus cells, much higher than that of CD34 + cells non transfected (3.2 ±1.1 %, P <0.01). And in presence of IFN γ or IL 2, the ratio reached 20.1±2.3 %, 17.6±1.3 % respectively ( P <0.01). However, IFN γ up regulated Fas expression of CD34 + cells and increased the sensibility of CD34 + cells to soluble FasL(sFasL); IL 2 showed no such affect. It is possible to induce apoptosis of the allo antigen specific T cells of grafts activated by allo antigen by exogenous Fas ligand expressed on recipient cells and this might provide a new approach for preventing GVHD and IL 2 may be more suitable for clinical application.展开更多
目的观察3种神经细胞保护措施对缺氧缺血性脑损伤新生大鼠脑组织凋亡相关因子及其配体(Fas和FasL)基因表达的影响。方法选择120只7日龄Wistar大鼠,按随机数字表法将大鼠分为神经干细胞组、促红细胞生成素(EPO)组、ω-3不饱和脂肪酸组、...目的观察3种神经细胞保护措施对缺氧缺血性脑损伤新生大鼠脑组织凋亡相关因子及其配体(Fas和FasL)基因表达的影响。方法选择120只7日龄Wistar大鼠,按随机数字表法将大鼠分为神经干细胞组、促红细胞生成素(EPO)组、ω-3不饱和脂肪酸组、缺氧缺血性脑损伤模型组,每组30只。神经干细胞组、EPO组、ω-3不饱和脂肪酸组于制模后经尾静脉注射5 mL神经干细胞、EPO、ω-3不饱和脂肪酸.缺氧缺血性脑损伤模型组给予等量生理盐水给药后6.12、24、48、72 h 5个时间点各组处死6只大鼠取海马组织.测定大脑海马组织Fas/FasL的基因表达,以及Toll样受体4(TLR4)、核转录因子-κB(NF-κB)、肿瘤坏死因子-α(TNF-α)、白细胞介素(IL-1β、IL-6)的蛋白表达水平和细胞凋亡率。结果①mRNA表达:3个实验组给药后Fas和FasL的mRNA表达均较缺氧缺血性脑损伤模型组显著降低,以给药后24h降低最为显著,且神经干细胞组VEPO组<ω-3不饱和脂肪酸组<缺氧缺血性脑损伤模型组〔FasmRNA表达(2^-△△Ct):140.5±2.9、156.4±2.5.165.2±2.7比173.7±2.8,FasL mRNA表达(2^-△△Ct):143.1±4.3、154.6±1.5,160.7±1.4比174.7±2.8],各组间比较差异均有统计学意义(均P<0.05)。②蛋白表达:3个实验组给药后海马组织TLR4、NF-κB、TNF-α、IL-1β、IL-6的蛋白表达水平均较缺氧缺血性脑损伤模型组显著降低(TLR4/GAPDH:0.7±0.2,0.6±0.1、0.2±0.1比1.4±0.1;NF-κB/GAPDH:6.7±0.4,5.3±0.1、1.1±0.2比11.2±0.3;TNF-α/GAPDH:14.3±1.4、11.2±1.2、3.2±2.1比23.2±0.5;IL-1β/GAPDH:9.4±0.2,7.4±0.3,2.2±0.3比13.4±0.1;IL-6/GAPDH:36.2±4.4.39.3±1.5、26.2±2.1比51.4±1.4,均P<0.05).神经干细胞组上述指标的蛋白表达水平VEPO组<ω-3不饱和脂肪酸组<缺氧缺血性脑损伤模型组:③细胞凋亡率:ω-3不饱和脂肪酸组、EPO组、神经干细胞组给药后海马组织细胞凋亡率均明显低于缺氧缺血性脑损伤模型组〔(3.7±0.3)%、(3.4±0.2)%、(2.5±0.1)%比(5.5±0.4)%,均P<0.05〕。结论缺氧缺血性脑损伤新生大鼠脑组织Fas和FasLmRNA呈高表达;而给予神经干细胞、EPO及ω-3不饱和脂肪酸处理均能减少脑组织Fas和FasL的mRNA表达.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.
文摘Apoptosis of thymocytes is involved in the negative selection of thymus, but it remains unclear how the cell death of thymocytes is regulated by the thymic stromal cells. By using immunohistochemistry, TdT mediated dUTP nick end labeling (TUNEL) and flow cytometry methods, it was found that Fas ligand was expressed in the thymic medulla and a mouse thymic medullary type dendritic cell line (MTSC4). The DNA fragmentation and TUNEL positive staining of thymocytes were detected in 6 h of cocultures with MTSC4. 97% of the thymocytes which bound to MTSC4 were Fas antigen positive cells. The DNA fragmentation of thymocytes induced by MTSC4 was inhibited by the addition of 20 mmol/L N acetyl galactosamin monosaccharide and the pretreatment of a monoclonal antibody (PF 18 3) which recognized a putative antigen on MTSC4. These results suggested that the mechanisms of induction of cell death by stromal cells may include the interactions of multiple cell surface molecules, in addition to the Fas/Fas ligand system.
基金This project was supported by a grant from National Natural Sciences Foundation of China(No.39770 76 7)
文摘The mechanism of chemotherapeutic drug-induced apoptosis in leukaemic cells was studied to further investigate whether Fas/FasL system was involved in apoptosis induced by chemotherapeutic drugs and assess their effects when used in combination with soluble FasL (sFasL). The expression of Fas on human leukaemic cell lines K562, HL-60 and U937 treated with daunorubicin (DNR) or cytosine arabinoside (Ara-C) was detected by using flow cytometry. The activities of sFasL, DNR and Ara-C inducing apoptosis of leukaemic cells, in the absence or presence of neutralizing anti-Fas IgG antibody, were detected by using flow cytometry and TUNEL. The results showed that flow cytometric profiles of K562, HL-60 and U937 cells treated with DNR or Ara-C failed to show any significant increase in Fas expression over 18 h (P>0.05). Anti-Fas monoclonal antibody (IgG) could not block the apoptosis in leukaemic cells induced by DNR or Ara-C, but could block the apoptosis induced by sFasL. A role of sFasL in a cytotoxic synergistic effect when used in combination with chemotherapeutic drugs was revealed. It was concluded that chemotherapeutic drug-induced apoptosis in human leukaemic cells (UG37, HL-60) is independent of the Fas/FasL system, but combination of sFasL and drug treatment produces a synergistic cytotoxic effect on human luekaemic cells.
基金Supported by The National Nature Science Fund (No.79970782)The National Outstanding Youth Fund (No.39625022).
文摘Purpose: To study the molecular mechanism of trabecular meshwork cells apoptosis induced by dexamethasone and the protection of pilocarpine.Methods: Determining mRNA expression with reverse transcription-polymerase chain reaction (RT-PCR), protein expression with Western blots and the percentage of apoptotic cells with fluorescent microscopy.Results: Dexamethasone up-regulated Fas proteins and affected Bax, caspase-8 and caspase-9 proteins in an action of first decrease then increase. Pre-treatment with pilocarpine decreased the four proteins expression, which were increased by dexamethasone. Pilocarpine self could decrease pro-apoptotic factors Bax, caspase-8 and caspase-9 proteins expression.Conclusion: Fas/FasL pathway participated in apoptotic process induced by dexamethasone in trabecular meshwork cells and the process was probably related with both caspase-8 and caspase-9 pathways. Pilocarpine protected the cells against apoptosis through down-regulating Fas, Bax, caspase-8 and caspase-9 proteins expression.
基金hisprojectwassupportedbythegrantfromNationalNaturalScienceFoundationofChina (No .39770 76 7)
文摘To investigate the value of apoptosis of the allo antigen specific T cells induced by Fas/FasL pathway in preventing graft versus host disease (GVHD), the CD34 + cells transfected with FasL or not, used as stimulus cells, were mixed with allo antigen specific T lymphocytes in presence or absence of IFN γand IL 2. After 5 days, apoptosis of T cells was detected by TdT nick end mediated dUTP labeling (TUNEL) and flow cytometry (FCM). The affects of these two cytokines on CD34 + cells in the graft were also compared. The ratio of apoptosis of T cells was 12.1±1.5 % when CD34 + cells transfected with FasL was used as stimulus cells, much higher than that of CD34 + cells non transfected (3.2 ±1.1 %, P <0.01). And in presence of IFN γ or IL 2, the ratio reached 20.1±2.3 %, 17.6±1.3 % respectively ( P <0.01). However, IFN γ up regulated Fas expression of CD34 + cells and increased the sensibility of CD34 + cells to soluble FasL(sFasL); IL 2 showed no such affect. It is possible to induce apoptosis of the allo antigen specific T cells of grafts activated by allo antigen by exogenous Fas ligand expressed on recipient cells and this might provide a new approach for preventing GVHD and IL 2 may be more suitable for clinical application.
文摘目的观察3种神经细胞保护措施对缺氧缺血性脑损伤新生大鼠脑组织凋亡相关因子及其配体(Fas和FasL)基因表达的影响。方法选择120只7日龄Wistar大鼠,按随机数字表法将大鼠分为神经干细胞组、促红细胞生成素(EPO)组、ω-3不饱和脂肪酸组、缺氧缺血性脑损伤模型组,每组30只。神经干细胞组、EPO组、ω-3不饱和脂肪酸组于制模后经尾静脉注射5 mL神经干细胞、EPO、ω-3不饱和脂肪酸.缺氧缺血性脑损伤模型组给予等量生理盐水给药后6.12、24、48、72 h 5个时间点各组处死6只大鼠取海马组织.测定大脑海马组织Fas/FasL的基因表达,以及Toll样受体4(TLR4)、核转录因子-κB(NF-κB)、肿瘤坏死因子-α(TNF-α)、白细胞介素(IL-1β、IL-6)的蛋白表达水平和细胞凋亡率。结果①mRNA表达:3个实验组给药后Fas和FasL的mRNA表达均较缺氧缺血性脑损伤模型组显著降低,以给药后24h降低最为显著,且神经干细胞组VEPO组<ω-3不饱和脂肪酸组<缺氧缺血性脑损伤模型组〔FasmRNA表达(2^-△△Ct):140.5±2.9、156.4±2.5.165.2±2.7比173.7±2.8,FasL mRNA表达(2^-△△Ct):143.1±4.3、154.6±1.5,160.7±1.4比174.7±2.8],各组间比较差异均有统计学意义(均P<0.05)。②蛋白表达:3个实验组给药后海马组织TLR4、NF-κB、TNF-α、IL-1β、IL-6的蛋白表达水平均较缺氧缺血性脑损伤模型组显著降低(TLR4/GAPDH:0.7±0.2,0.6±0.1、0.2±0.1比1.4±0.1;NF-κB/GAPDH:6.7±0.4,5.3±0.1、1.1±0.2比11.2±0.3;TNF-α/GAPDH:14.3±1.4、11.2±1.2、3.2±2.1比23.2±0.5;IL-1β/GAPDH:9.4±0.2,7.4±0.3,2.2±0.3比13.4±0.1;IL-6/GAPDH:36.2±4.4.39.3±1.5、26.2±2.1比51.4±1.4,均P<0.05).神经干细胞组上述指标的蛋白表达水平VEPO组<ω-3不饱和脂肪酸组<缺氧缺血性脑损伤模型组:③细胞凋亡率:ω-3不饱和脂肪酸组、EPO组、神经干细胞组给药后海马组织细胞凋亡率均明显低于缺氧缺血性脑损伤模型组〔(3.7±0.3)%、(3.4±0.2)%、(2.5±0.1)%比(5.5±0.4)%,均P<0.05〕。结论缺氧缺血性脑损伤新生大鼠脑组织Fas和FasLmRNA呈高表达;而给予神经干细胞、EPO及ω-3不饱和脂肪酸处理均能减少脑组织Fas和FasL的mRNA表达.
