Integrins are a family of transmembrane glycoproteins that mediate cell-cell and cell-extracellular matrix interactions. The integrin α4 subunit is widely expressed by cells from the immune system and its expression ...Integrins are a family of transmembrane glycoproteins that mediate cell-cell and cell-extracellular matrix interactions. The integrin α4 subunit is widely expressed by cells from the immune system and its expression by non-hematopoietic cells is scarce. In the present study, gene and protein expression of this integrin subunit was characterized in proliferating and quiescent human RPE cells. Immunofluorescent studies confirm that the α4 subunit is expressed in vitro by RPE cells, a result that has been validated by immunofluorescence and FACS analyses. The accumulation of the α4 integrin at cell-cell junctions in post-confluent RPE cell cultures negatively correlated with the level of expression of the mRNA transcript. Accordingly, transient transfection analyses reveal that the α4 promoter activity is considerably reduced when RPE cells form a confluent monolayer. Moreover, transfection of recombinant constructs bearing 5’-deletions of the α4 promoter segment allows the localization of strong negative regulatory elements on the -76 to -300 region of the α4 gene suggesting that its expression is intimately linked to the proliferative state of primary cultured RPE cells.展开更多
目的探讨β4整合素结合蛋白ITGB4BP对Wnt/β-catenin信号通路的影响。方法将对照组空载体pCMV-3B质粒和实验组pCMV-ITGB4BP质粒分别转染至HEK293细胞中,用Western blot和激光共聚焦技术检测细胞中β-catenin含量的变化,用含TCF/LEF启动...目的探讨β4整合素结合蛋白ITGB4BP对Wnt/β-catenin信号通路的影响。方法将对照组空载体pCMV-3B质粒和实验组pCMV-ITGB4BP质粒分别转染至HEK293细胞中,用Western blot和激光共聚焦技术检测细胞中β-catenin含量的变化,用含TCF/LEF启动子的荧光素酶TOPFlash质粒和内参pRL-TK质粒共转染对照组和实验组的HEK293细胞,用荧光素酶活性分析法检测ITGB4BP转染后HEK293细胞TCF/LEF活性的变化。设不转染质粒组为正常组,对照组和实验组均分别设未加LiCl组和加LiCl组。结果 Western blot检测结果:与正常组或对照组比较,实验组细胞β-catenin表达显著减少(P<0.05)。加LiCl之后,β-catenin的表达显著增强(P<0.05),与未加有LiCl的正常组或对照组比较,加LiCl的实验组细胞内β-catenin仍有较高的表达,但差异无显著性。激光共聚焦技术观察:实验组β-catenin(绿色荧光)表达较对照组降低。加LiCl之后,β-catenin(绿色荧光)表达增强,与未加LiCl的对照组相比,加LiCl的实验组仍有较强的荧光强度。荧光素酶活性分析法检测:实验组的荧光素酶活性较对照组显著降低(P<0.05)。LiCl作用之后,Wnt/β-catenin信号通路活性明显增强(P<0.05),与未加LiCl的对照组相比,加LiCl的实验组仍有较强的荧光素酶活性(P<0.05)。结论ITGB4BP可以下调Wnt/β-catenin信号通路的活性。展开更多
Medical treatment has progressed significantly over the past decade towards achieving and maintaining clinical remission in patients with refractory ulcerative colitis(UC). Proposed mediators of inflammation in UC inc...Medical treatment has progressed significantly over the past decade towards achieving and maintaining clinical remission in patients with refractory ulcerative colitis(UC). Proposed mediators of inflammation in UC include pro-inflammatory cytokines such as tumor necrosis factor-α(TNF-α) and interleukin-2, and the cellsurface adhesive molecule integrin α4β7. Conventional therapeutics for active UC include 5-aminosalicylic acid, corticosteroids and purine analogues(azathioprine and 6-mercaptopurine). Patients who fail to respond to conventional therapy are treated with agents such as the calicineurin inhibitors cyclosporine and tacrolimus, the TNF-α inhibitors infliximab or adalimumab, or a neutralizing antibody(vedolizumab) directed against integrin α4β7. These therapeutic agents are of benefit for patients with refractory UC, but are not universally effective. Our recent research on TNF-α shedding demonstrated that inhibition of annexin(ANX) A2 may be a new therapeutic strategy for the prevention of TNF-α shedding during inflammatory bowel disease(IBD) inflammation. In this review, we provide an overview of therapeutic treatments that are effective and currently available for UC patients, as well as some that are likely to be available in the near future. We also propose the potential of ANX A2 as a new molecular target for IBD treatment.展开更多
文摘Integrins are a family of transmembrane glycoproteins that mediate cell-cell and cell-extracellular matrix interactions. The integrin α4 subunit is widely expressed by cells from the immune system and its expression by non-hematopoietic cells is scarce. In the present study, gene and protein expression of this integrin subunit was characterized in proliferating and quiescent human RPE cells. Immunofluorescent studies confirm that the α4 subunit is expressed in vitro by RPE cells, a result that has been validated by immunofluorescence and FACS analyses. The accumulation of the α4 integrin at cell-cell junctions in post-confluent RPE cell cultures negatively correlated with the level of expression of the mRNA transcript. Accordingly, transient transfection analyses reveal that the α4 promoter activity is considerably reduced when RPE cells form a confluent monolayer. Moreover, transfection of recombinant constructs bearing 5’-deletions of the α4 promoter segment allows the localization of strong negative regulatory elements on the -76 to -300 region of the α4 gene suggesting that its expression is intimately linked to the proliferative state of primary cultured RPE cells.
文摘目的探讨β4整合素结合蛋白ITGB4BP对Wnt/β-catenin信号通路的影响。方法将对照组空载体pCMV-3B质粒和实验组pCMV-ITGB4BP质粒分别转染至HEK293细胞中,用Western blot和激光共聚焦技术检测细胞中β-catenin含量的变化,用含TCF/LEF启动子的荧光素酶TOPFlash质粒和内参pRL-TK质粒共转染对照组和实验组的HEK293细胞,用荧光素酶活性分析法检测ITGB4BP转染后HEK293细胞TCF/LEF活性的变化。设不转染质粒组为正常组,对照组和实验组均分别设未加LiCl组和加LiCl组。结果 Western blot检测结果:与正常组或对照组比较,实验组细胞β-catenin表达显著减少(P<0.05)。加LiCl之后,β-catenin的表达显著增强(P<0.05),与未加有LiCl的正常组或对照组比较,加LiCl的实验组细胞内β-catenin仍有较高的表达,但差异无显著性。激光共聚焦技术观察:实验组β-catenin(绿色荧光)表达较对照组降低。加LiCl之后,β-catenin(绿色荧光)表达增强,与未加LiCl的对照组相比,加LiCl的实验组仍有较强的荧光强度。荧光素酶活性分析法检测:实验组的荧光素酶活性较对照组显著降低(P<0.05)。LiCl作用之后,Wnt/β-catenin信号通路活性明显增强(P<0.05),与未加LiCl的对照组相比,加LiCl的实验组仍有较强的荧光素酶活性(P<0.05)。结论ITGB4BP可以下调Wnt/β-catenin信号通路的活性。
基金Supported by Grant-in-Aid for Scientific Research(C)from Japan Society for the Promotion of Science,No.25460957
文摘Medical treatment has progressed significantly over the past decade towards achieving and maintaining clinical remission in patients with refractory ulcerative colitis(UC). Proposed mediators of inflammation in UC include pro-inflammatory cytokines such as tumor necrosis factor-α(TNF-α) and interleukin-2, and the cellsurface adhesive molecule integrin α4β7. Conventional therapeutics for active UC include 5-aminosalicylic acid, corticosteroids and purine analogues(azathioprine and 6-mercaptopurine). Patients who fail to respond to conventional therapy are treated with agents such as the calicineurin inhibitors cyclosporine and tacrolimus, the TNF-α inhibitors infliximab or adalimumab, or a neutralizing antibody(vedolizumab) directed against integrin α4β7. These therapeutic agents are of benefit for patients with refractory UC, but are not universally effective. Our recent research on TNF-α shedding demonstrated that inhibition of annexin(ANX) A2 may be a new therapeutic strategy for the prevention of TNF-α shedding during inflammatory bowel disease(IBD) inflammation. In this review, we provide an overview of therapeutic treatments that are effective and currently available for UC patients, as well as some that are likely to be available in the near future. We also propose the potential of ANX A2 as a new molecular target for IBD treatment.
