Epidermal growth factor （EGF） may increase cell motility, an event implicated in cancer cell invasion and metastasis. However, the underlying mechanisms for EGF-induced cell motility remain elusive. In this study, w...Epidermal growth factor （EGF） may increase cell motility, an event implicated in cancer cell invasion and metastasis. However, the underlying mechanisms for EGF-induced cell motility remain elusive. In this study, we found that EGF treatment could activate Ras-related C3 botulinum toxin substrate 1 （Racl）, PI3K/Akt and p21- actived kinase （PAK1） along with cell migration. Ectopic expression of PAK1 K299R, a dominant negative PAK1 mutant, could largely abolish EGF-induced cell migration. Blocking PI3K/Akt signalling with LY294002 or Akt siRNA remarkably inhibited both EGF-induced PAK1 activation and cell migration. Furthermore, expression of dominant-negative Racl （T17N） could largely block EGF-induced PI3K/Akt-PAK1 activation and cell migration. Interestingly, EGF could induce a significant production of ROS, and N-acetyl-L-cysteine, a scavenger of ROS which abolished the EGF-induced ROS generation, cell migration, as well as activation of PI3K/Akt and PAK, but not Racl. Our study demonstrated that EGF-induced cell migration involves a cascade of signalling events, including activation of Racl, generation of ROS and subsequent activation of PI3K/Akt and PAK1.展开更多
Regulatory T cells （Tregs） are critical for the peripheral maintenance of the autoreactive T cells in autoimmune disorders such as type 1 diabetes （TID）. Pharmacological inhibition of Janus tyrosine kinase 3 （JAK...Regulatory T cells （Tregs） are critical for the peripheral maintenance of the autoreactive T cells in autoimmune disorders such as type 1 diabetes （TID）. Pharmacological inhibition of Janus tyrosine kinase 3 （JAK3） has been proposed as a basis for new treatment modalities against autoimmunity and allogeneic responses. Targeting JAK3 with an inhibitor has previously been shown to exhibit protective action against the development of T 1D in non-obese diabetic （NOD） mice. As the mechanism of such preventative action has been unknown, we hypothesized that JAK3 inhibition induces generation of Tregs. Here, we show that the JAK3 inhibitor 4-（4＇-hydroxyphenyl）-amino-6,7-dimethoxyquinazoline （WHI-P131） suppresses proliferation of short-term cultured NOD CD4＋ T cells through induction of apoptosis, while promoting survival of a particular population of long-term cultured cells. It was found that the surviving cells were not of the CD4＋CD25＋FoxP3＋ phenotype. They secreted decreased amounts of IL-IO, IL-4 and interferon （IFN）-y compared to the cells not exposed to the optimal concentrations of JAK3 inhibitor. However, an elevated transforming growth factor （TGF）-β secretion was detected in their supernatants. In vivo treatment of prediabetic NOD mice with WHI-P131 did not affect the frequency and number of splenic and pancreatic lymph node CD4＋FoxP3＋ Tregs, while generating an elevated numbers of CD4＋FoxP3- TGF-β-secreting T cells. In conclusion, our data suggest an induction of TGF-β-secreting CD4＋ T cells as the underlying mechanism for antidiabetogenic effects obtained by the treatment with a JAK3 inhibitor. To our knowledge, this is the first report of the JAK3 inhibitor activity in the context of the murine Tregs.展开更多
BACKGROUND Pediatric enteritis is one of the infectious diseases in the digestive system that causes a variety of digestive problems,including diarrhea,vomiting,and bellyache in children.Clinically,Helicobacter pylori...BACKGROUND Pediatric enteritis is one of the infectious diseases in the digestive system that causes a variety of digestive problems,including diarrhea,vomiting,and bellyache in children.Clinically,Helicobacter pylori(H.pylori)infection is one of the common factors to cause pediatric enteritis.It has been demonstrated that aberrant expression of microRNAs(miRNAs)is found in gastrointestinal diseases caused by H.pylori,and we discovered a significant increase of miR-32-5p in H.pylori-related pediatric enteritis.However,the exact role of miR-32-5p in it is still unknown.AIM To investigate the role of aberrant miR-32-5p in pediatric enteritis induced by H.pylori.METHODS MiR-32-5p expression was detected by quantitative real time-polymerase chain reaction.The biological role of miR-32-5p in H.pylori-treated intestinal epithelial cells was evaluated by Cell Counting Kit-8 assay and flow cytometry.The potential target of miR-32-5p was predicted with TargetScanHuman and verified by luciferase assay.The downstream mechanism of miR-32-5p was explored by using molecular biology methods.RESULTS We found that miR-32-5p was overexpressed in serum of H.pylori-induced pediatric enteritis.Further investigation revealed that H.pylori infection promoted the death of intestinal epithelial cells,and increased miR-32-5p expression.Moreover,miR-32-5p mimic further facilitated apoptosis and inflammatory cytokine secretion of intestinal epithelial cells.Further exploration revealed that SMAD family member 6(SMAD6)was the direct target of miR-32-5p,and SMAD6 overexpression partially rescued cell damage induced by H.pylori.The following experiments showed that miR-32-5p/SMAD6 participated in the apoptosis of intestinal epithelial cells induced by transforming growth factor-β-activated kinase 1(TAK1)-p38 activation under H.pylori infection.CONCLUSION Our work uncovered the crucial role of aberrant expression of miR-32-5p in H.pylori–related pediatric enteritis,and suggested that the TAK1-p38 pathway is involved in it.展开更多
基金supported by grants from the National Natural Science Foundation of China (No. 30872926)the Program for AdvancedTalents within Six Industries of Jiangsu Province (08-D) to Dr. Luo Gu+1 种基金the Science Development Foundation of Nanjing Medical University (No. 2010NJMUZ35)the Research Program funded by Schoolof Basic Medical Science, Nanjing Medical University to Dr. Jun Du
文摘Epidermal growth factor （EGF） may increase cell motility, an event implicated in cancer cell invasion and metastasis. However, the underlying mechanisms for EGF-induced cell motility remain elusive. In this study, we found that EGF treatment could activate Ras-related C3 botulinum toxin substrate 1 （Racl）, PI3K/Akt and p21- actived kinase （PAK1） along with cell migration. Ectopic expression of PAK1 K299R, a dominant negative PAK1 mutant, could largely abolish EGF-induced cell migration. Blocking PI3K/Akt signalling with LY294002 or Akt siRNA remarkably inhibited both EGF-induced PAK1 activation and cell migration. Furthermore, expression of dominant-negative Racl （T17N） could largely block EGF-induced PI3K/Akt-PAK1 activation and cell migration. Interestingly, EGF could induce a significant production of ROS, and N-acetyl-L-cysteine, a scavenger of ROS which abolished the EGF-induced ROS generation, cell migration, as well as activation of PI3K/Akt and PAK, but not Racl. Our study demonstrated that EGF-induced cell migration involves a cascade of signalling events, including activation of Racl, generation of ROS and subsequent activation of PI3K/Akt and PAK1.
文摘Regulatory T cells （Tregs） are critical for the peripheral maintenance of the autoreactive T cells in autoimmune disorders such as type 1 diabetes （TID）. Pharmacological inhibition of Janus tyrosine kinase 3 （JAK3） has been proposed as a basis for new treatment modalities against autoimmunity and allogeneic responses. Targeting JAK3 with an inhibitor has previously been shown to exhibit protective action against the development of T 1D in non-obese diabetic （NOD） mice. As the mechanism of such preventative action has been unknown, we hypothesized that JAK3 inhibition induces generation of Tregs. Here, we show that the JAK3 inhibitor 4-（4＇-hydroxyphenyl）-amino-6,7-dimethoxyquinazoline （WHI-P131） suppresses proliferation of short-term cultured NOD CD4＋ T cells through induction of apoptosis, while promoting survival of a particular population of long-term cultured cells. It was found that the surviving cells were not of the CD4＋CD25＋FoxP3＋ phenotype. They secreted decreased amounts of IL-IO, IL-4 and interferon （IFN）-y compared to the cells not exposed to the optimal concentrations of JAK3 inhibitor. However, an elevated transforming growth factor （TGF）-β secretion was detected in their supernatants. In vivo treatment of prediabetic NOD mice with WHI-P131 did not affect the frequency and number of splenic and pancreatic lymph node CD4＋FoxP3＋ Tregs, while generating an elevated numbers of CD4＋FoxP3- TGF-β-secreting T cells. In conclusion, our data suggest an induction of TGF-β-secreting CD4＋ T cells as the underlying mechanism for antidiabetogenic effects obtained by the treatment with a JAK3 inhibitor. To our knowledge, this is the first report of the JAK3 inhibitor activity in the context of the murine Tregs.
文摘BACKGROUND Pediatric enteritis is one of the infectious diseases in the digestive system that causes a variety of digestive problems,including diarrhea,vomiting,and bellyache in children.Clinically,Helicobacter pylori(H.pylori)infection is one of the common factors to cause pediatric enteritis.It has been demonstrated that aberrant expression of microRNAs(miRNAs)is found in gastrointestinal diseases caused by H.pylori,and we discovered a significant increase of miR-32-5p in H.pylori-related pediatric enteritis.However,the exact role of miR-32-5p in it is still unknown.AIM To investigate the role of aberrant miR-32-5p in pediatric enteritis induced by H.pylori.METHODS MiR-32-5p expression was detected by quantitative real time-polymerase chain reaction.The biological role of miR-32-5p in H.pylori-treated intestinal epithelial cells was evaluated by Cell Counting Kit-8 assay and flow cytometry.The potential target of miR-32-5p was predicted with TargetScanHuman and verified by luciferase assay.The downstream mechanism of miR-32-5p was explored by using molecular biology methods.RESULTS We found that miR-32-5p was overexpressed in serum of H.pylori-induced pediatric enteritis.Further investigation revealed that H.pylori infection promoted the death of intestinal epithelial cells,and increased miR-32-5p expression.Moreover,miR-32-5p mimic further facilitated apoptosis and inflammatory cytokine secretion of intestinal epithelial cells.Further exploration revealed that SMAD family member 6(SMAD6)was the direct target of miR-32-5p,and SMAD6 overexpression partially rescued cell damage induced by H.pylori.The following experiments showed that miR-32-5p/SMAD6 participated in the apoptosis of intestinal epithelial cells induced by transforming growth factor-β-activated kinase 1(TAK1)-p38 activation under H.pylori infection.CONCLUSION Our work uncovered the crucial role of aberrant expression of miR-32-5p in H.pylori–related pediatric enteritis,and suggested that the TAK1-p38 pathway is involved in it.
