AIM:To investigate lipopolysaccharide(LPS) related signal transduction in interstitial cells of Cajal(ICCs) from mouse small intestine.METHODS:For this study,primary culture of ICCs was prepared from the small intesti...AIM:To investigate lipopolysaccharide(LPS) related signal transduction in interstitial cells of Cajal(ICCs) from mouse small intestine.METHODS:For this study,primary culture of ICCs was prepared from the small intestine of the mouse.LPS was treated to the cells prior to measurement of the membrane currents by using whole-cell patch clamp technique.Immunocytochemistry was used to examine the expression of the proteins in ICCs.RESULTS:LPS suppressed the pacemaker currents of ICCs and this could be blocked by AH6809,a prostaglandin E2-EP2 receptor antagonist or NG-Nitro-Larginine Methyl Ester,an inhibitor of nitric oxide(NO) synthase.Toll-like receptor 4,inducible NO synthase or cyclooxygenase-2 immunoreactivity by specific antibodies was detected on ICCs.Catalase(antioxidant agent) had no action on LPS-induced action in ICCs.LPS actions were blocked by nuclear factor kB(NF-kB) inhibitor,actinomycin D(a gene transcription inhibitor),PD 98059(a p42/44 mitogen-activated protein kinases inhibitor) or SB 203580 [a p38 mitogen-activated protein kinases(MAPK) inhibitor].SB 203580 also blocked the prostaglandin E2-induced action on pacemaker currents in ICCs but not NO.CONCLUSION:LPS inhibit the pacemaker currents in ICCs via prostaglandin E2-and NO-dependent mechanism through toll-like receptor 4 and suggest that MAPK and NF-kB are implicated in these actions.展开更多
Cancer metabolism and epigenetic alteration are two critical mechanisms for tumorigenesis and cancer progres?sion; however, the dynamic interplay between them remains poorly understood. As reported in the article enti...Cancer metabolism and epigenetic alteration are two critical mechanisms for tumorigenesis and cancer progres?sion; however, the dynamic interplay between them remains poorly understood. As reported in the article entitled "Chromatin remodeling factor LSH drives cancer progression by suppressing the activity of fumarate hydratase," which was recently published in Cancer Research, our group examined the physiological role of lymphocyte?specific heli?case(LSH) in nasopharyngeal carcinoma(NPC) by focusing on cancer progression and the tricarboxylic acid cycle. We found that LSH was overexpressed in NPC, and its expression associated with Epstein?Barr virus infection. We also found that LSH directly suppressed fumarate hydratase(FH), a key component of the tricarboxylic acid cycle, in combination with euchromatic histone?lysine N?methyltransferase 2(EHMT2), also known as G9 a. Depletion of FH promoted epithelial?mesenchymal transition(EMT). Moreover, LSH controlled expression of tricarboxylic acid cycle intermediates that promote cancer progression, including EMT, through activation by inhibitor of nuclear factor kappa?B kinase alpha(IKKα), a chromatin modifier and transcriptional activator. Our study showed that LSH plays a critical role in cancer progression, which has important implications for the development of novel strategies to treat NPC.展开更多
Using forward and reverse genetics and global gene expression analyses, we explored the crosstalk between the IKB kinase β （IKKβ） and the transforming growth factor β （TGFβ） signaling pathways. We show that in...Using forward and reverse genetics and global gene expression analyses, we explored the crosstalk between the IKB kinase β （IKKβ） and the transforming growth factor β （TGFβ） signaling pathways. We show that in vitro ablation of Ikkβ in fibroblasts led to progressive ROS accumulation and TGFβ activation, and ultimately accelerated cell migration, fibroblast-myofibroblast transformation and senescence. Mechanistically, the basal IKKβ activity was required for anti-oxidant gene expression and redox homeostasis. Lacking this activity, IKKβ-null cells showed ROS accumulation and activation of stress-sensitive transcription factor AP-1/c- Jun. AP-1/c-Jun activation led to up-regulation of the Tgfβ2 promoter, which in turn further potentiated intracellular ROS through the induction of NADPH oxidase （NOX）. These data suggest that by blocking the autocrine amplification of a ROS-TGFβ loop IKKβ plays a crucial role in the prevention of fibroblast-myofibroblast transformation and senescence.展开更多
基金Supported by Basic Science Research Program through the National Research Foundation of Korea funded by the Ministry of Education,Science and Technology,No.2012-0001335
文摘AIM:To investigate lipopolysaccharide(LPS) related signal transduction in interstitial cells of Cajal(ICCs) from mouse small intestine.METHODS:For this study,primary culture of ICCs was prepared from the small intestine of the mouse.LPS was treated to the cells prior to measurement of the membrane currents by using whole-cell patch clamp technique.Immunocytochemistry was used to examine the expression of the proteins in ICCs.RESULTS:LPS suppressed the pacemaker currents of ICCs and this could be blocked by AH6809,a prostaglandin E2-EP2 receptor antagonist or NG-Nitro-Larginine Methyl Ester,an inhibitor of nitric oxide(NO) synthase.Toll-like receptor 4,inducible NO synthase or cyclooxygenase-2 immunoreactivity by specific antibodies was detected on ICCs.Catalase(antioxidant agent) had no action on LPS-induced action in ICCs.LPS actions were blocked by nuclear factor kB(NF-kB) inhibitor,actinomycin D(a gene transcription inhibitor),PD 98059(a p42/44 mitogen-activated protein kinases inhibitor) or SB 203580 [a p38 mitogen-activated protein kinases(MAPK) inhibitor].SB 203580 also blocked the prostaglandin E2-induced action on pacemaker currents in ICCs but not NO.CONCLUSION:LPS inhibit the pacemaker currents in ICCs via prostaglandin E2-and NO-dependent mechanism through toll-like receptor 4 and suggest that MAPK and NF-kB are implicated in these actions.
基金supported by grants from the National Basic Research Program of China[2015CB553903(YGT)]the National Natural Science Foundation of China[81171881 and 81372427(YGT)and 81271763(SL)]the Hunan Natural Science Foundation of China[12JJ1013(YGT)]
文摘Cancer metabolism and epigenetic alteration are two critical mechanisms for tumorigenesis and cancer progres?sion; however, the dynamic interplay between them remains poorly understood. As reported in the article entitled "Chromatin remodeling factor LSH drives cancer progression by suppressing the activity of fumarate hydratase," which was recently published in Cancer Research, our group examined the physiological role of lymphocyte?specific heli?case(LSH) in nasopharyngeal carcinoma(NPC) by focusing on cancer progression and the tricarboxylic acid cycle. We found that LSH was overexpressed in NPC, and its expression associated with Epstein?Barr virus infection. We also found that LSH directly suppressed fumarate hydratase(FH), a key component of the tricarboxylic acid cycle, in combination with euchromatic histone?lysine N?methyltransferase 2(EHMT2), also known as G9 a. Depletion of FH promoted epithelial?mesenchymal transition(EMT). Moreover, LSH controlled expression of tricarboxylic acid cycle intermediates that promote cancer progression, including EMT, through activation by inhibitor of nuclear factor kappa?B kinase alpha(IKKα), a chromatin modifier and transcriptional activator. Our study showed that LSH plays a critical role in cancer progression, which has important implications for the development of novel strategies to treat NPC.
文摘Using forward and reverse genetics and global gene expression analyses, we explored the crosstalk between the IKB kinase β （IKKβ） and the transforming growth factor β （TGFβ） signaling pathways. We show that in vitro ablation of Ikkβ in fibroblasts led to progressive ROS accumulation and TGFβ activation, and ultimately accelerated cell migration, fibroblast-myofibroblast transformation and senescence. Mechanistically, the basal IKKβ activity was required for anti-oxidant gene expression and redox homeostasis. Lacking this activity, IKKβ-null cells showed ROS accumulation and activation of stress-sensitive transcription factor AP-1/c- Jun. AP-1/c-Jun activation led to up-regulation of the Tgfβ2 promoter, which in turn further potentiated intracellular ROS through the induction of NADPH oxidase （NOX）. These data suggest that by blocking the autocrine amplification of a ROS-TGFβ loop IKKβ plays a crucial role in the prevention of fibroblast-myofibroblast transformation and senescence.
