AIM:To examine the activation of the Nalp3 inflammasome and its downstream targets following lipopolysaccharide(LPS) -induced stimulation in the liver. METHODS:Six-to-eight-week-old C57BL/6 chow fed mice were injected...AIM:To examine the activation of the Nalp3 inflammasome and its downstream targets following lipopolysaccharide(LPS) -induced stimulation in the liver. METHODS:Six-to-eight-week-old C57BL/6 chow fed mice were injected intraperitoneally with 0.5μg/g bodyweight LPS and sacrificed 2,4,6,18 or 24 h later. LPS-induced liver damage was confirmed by a biochemical assay to detect alanine aminotransferase(ALT) levels.To determine if LPS stimulation in the liver led to activation of the inflammasome,real-time quantitative polymerase chain reaction was used to evaluate the mRNA expression of components of the Nalp3 inflammasome.Enzyme-linked immunosorbent assays were used to determine the protein expression levels of several downstream targets of the Nalp3 inflammasome,including caspase-1 and two cytokine targets of caspase-1,interleukin(IL) -1βand IL-18. RESULTS:We found that LPS injection resulted in liver damage as indicated by elevated ALT levels.This was associated with a significant increase in both mRNA and protein levels of the proinflammatory cy-tokine tumor necrosis factor(TNF) -αin the liver,as well as increased levels of TNFs in serum.We showed that LPS stimulation led to upregulation of mRNA levels in the liver for all the receptor components of the inflammasome,including Nalp3,Nalp1,pannexin-1 and the adaptor molecule apoptosis-associated specklike,caspase recruitment domain-domain containing protein.We also found increased levels of mRNA and protein for caspase-1,a downstream target of the inflammasome.In addition,LPS challenge led to increased levels of both mRNA and protein in the liver for two cytokine targets of caspase-1,IL-1βand IL-18. Interestingly,substantial baseline expression of pre-IL1βand pre-IL-18 was found in the liver.Inflammasome and caspase-1 activation was indicated by the significant increase in the active forms of IL-1βand IL-18 after LPS stimulation. CONCLUSION:Our results show that the Nalp3 inflammasome is upregulated and activated in the liver in response to LPS stimulation.展开更多
We investigated the effects of lipopolysaccharide （LPS） and dopamine （DA） on the activation of the prophenoloxidase （proPO） system of Litopenaeus vannamei. LPS and DA were shown with a negative dose-dependent ef...We investigated the effects of lipopolysaccharide （LPS） and dopamine （DA） on the activation of the prophenoloxidase （proPO） system of Litopenaeus vannamei. LPS and DA were shown with a negative dose-dependent effect on hyalne cells （HC）, semi-granular cells （SGC）, large granular cells （LGC）, and total haemocyte count （THC）. When haemocytes were treated with LPS or DA, serine proteinase activity and intracellular phenoloxidase （PO） activity were significantly reduced, but extracellular PO activity increased significantly. These findings indicated that the reduction in haemocyte counts was mainly because of the degranulation and activation of the proPO system from semi-granule and large granule cells. The PKC inhibitor, chelerythrine, and the TPK inhibitor, genistein, had an inhibitory effect on extracellular PO activity, while serine proteinase and intracellular PO activity increased. This suggests that the LPS and DA induce the activation of proPO in haemocytes via PKC and TPK-related signaling pathways, but serine proteinase may be activated only by PKC, as the genistein effects were not statistically significant. Electrophoresis analysis revealed that POs induced by LPS or DA have the same molecular mass and high diphenolase activity. Two PO bands at 526 kDa and 272 kDa were observed in PAGE, while in the haemocyte lysate supematant （HLS）, only a 272-kDa band was observed. This band was resolved after SDS-PAGE under non-reducing and reducing conditions into two groups of POs, 166 kDa and 126 kDa, and 78.1 kDa and 73.6 kDa, respectively, suggesting that PO in L. vannamei is an oligomer, which may have different compositions intra- and extracellularly.展开更多
Objective It has been shown that there are extensive interactions between the central nervous system and the immune system.The present study focused on the effects of lipopolysaccharide（LPS）on memory retrieval,to ex...Objective It has been shown that there are extensive interactions between the central nervous system and the immune system.The present study focused on the effects of lipopolysaccharide（LPS）on memory retrieval,to explore the interaction between immune activation and memory.Methods C57BL/6J mice（8 weeks old）were first trained in the Morris water maze to reach asymptotic performance.Then mice were tested 24 h after the last training session and LPS was administered（1.25 mg/kg,i.p.）4 h prior to the testing.The retrieval of spatial memory was tested by probe trial,and the time spent in the target quadrant and the number of platform location crosses were recorded.ELISA was performed to detect interleukin-1β（IL-1β）protein level in the hippocampus of mice tested in the water maze.Results Although LPS induced overt sickness behavior and a significant increase in the level of IL-1β in the hippocampus of mice,there was no significant difference in the time spent in the target quadrant or in the number of platform location crosses between LPS-treated and control groups in the probe trial testing.Conclusion Immune activation induced by LPS does not impair the retrieval of spatial memory.展开更多
文摘AIM:To examine the activation of the Nalp3 inflammasome and its downstream targets following lipopolysaccharide(LPS) -induced stimulation in the liver. METHODS:Six-to-eight-week-old C57BL/6 chow fed mice were injected intraperitoneally with 0.5μg/g bodyweight LPS and sacrificed 2,4,6,18 or 24 h later. LPS-induced liver damage was confirmed by a biochemical assay to detect alanine aminotransferase(ALT) levels.To determine if LPS stimulation in the liver led to activation of the inflammasome,real-time quantitative polymerase chain reaction was used to evaluate the mRNA expression of components of the Nalp3 inflammasome.Enzyme-linked immunosorbent assays were used to determine the protein expression levels of several downstream targets of the Nalp3 inflammasome,including caspase-1 and two cytokine targets of caspase-1,interleukin(IL) -1βand IL-18. RESULTS:We found that LPS injection resulted in liver damage as indicated by elevated ALT levels.This was associated with a significant increase in both mRNA and protein levels of the proinflammatory cy-tokine tumor necrosis factor(TNF) -αin the liver,as well as increased levels of TNFs in serum.We showed that LPS stimulation led to upregulation of mRNA levels in the liver for all the receptor components of the inflammasome,including Nalp3,Nalp1,pannexin-1 and the adaptor molecule apoptosis-associated specklike,caspase recruitment domain-domain containing protein.We also found increased levels of mRNA and protein for caspase-1,a downstream target of the inflammasome.In addition,LPS challenge led to increased levels of both mRNA and protein in the liver for two cytokine targets of caspase-1,IL-1βand IL-18. Interestingly,substantial baseline expression of pre-IL1βand pre-IL-18 was found in the liver.Inflammasome and caspase-1 activation was indicated by the significant increase in the active forms of IL-1βand IL-18 after LPS stimulation. CONCLUSION:Our results show that the Nalp3 inflammasome is upregulated and activated in the liver in response to LPS stimulation.
基金Supported by the New Century Excellent Talents in University(No.NCET-06-0597)Introducing Talents of Discipline of Universities(111Project)(No.B08049)
文摘We investigated the effects of lipopolysaccharide （LPS） and dopamine （DA） on the activation of the prophenoloxidase （proPO） system of Litopenaeus vannamei. LPS and DA were shown with a negative dose-dependent effect on hyalne cells （HC）, semi-granular cells （SGC）, large granular cells （LGC）, and total haemocyte count （THC）. When haemocytes were treated with LPS or DA, serine proteinase activity and intracellular phenoloxidase （PO） activity were significantly reduced, but extracellular PO activity increased significantly. These findings indicated that the reduction in haemocyte counts was mainly because of the degranulation and activation of the proPO system from semi-granule and large granule cells. The PKC inhibitor, chelerythrine, and the TPK inhibitor, genistein, had an inhibitory effect on extracellular PO activity, while serine proteinase and intracellular PO activity increased. This suggests that the LPS and DA induce the activation of proPO in haemocytes via PKC and TPK-related signaling pathways, but serine proteinase may be activated only by PKC, as the genistein effects were not statistically significant. Electrophoresis analysis revealed that POs induced by LPS or DA have the same molecular mass and high diphenolase activity. Two PO bands at 526 kDa and 272 kDa were observed in PAGE, while in the haemocyte lysate supematant （HLS）, only a 272-kDa band was observed. This band was resolved after SDS-PAGE under non-reducing and reducing conditions into two groups of POs, 166 kDa and 126 kDa, and 78.1 kDa and 73.6 kDa, respectively, suggesting that PO in L. vannamei is an oligomer, which may have different compositions intra- and extracellularly.
基金supported by the National Natural Science Foundation of China(No.30700213)National Basic Research Development Program of China(No.2007CB947804)
文摘Objective It has been shown that there are extensive interactions between the central nervous system and the immune system.The present study focused on the effects of lipopolysaccharide（LPS）on memory retrieval,to explore the interaction between immune activation and memory.Methods C57BL/6J mice（8 weeks old）were first trained in the Morris water maze to reach asymptotic performance.Then mice were tested 24 h after the last training session and LPS was administered（1.25 mg/kg,i.p.）4 h prior to the testing.The retrieval of spatial memory was tested by probe trial,and the time spent in the target quadrant and the number of platform location crosses were recorded.ELISA was performed to detect interleukin-1β（IL-1β）protein level in the hippocampus of mice tested in the water maze.Results Although LPS induced overt sickness behavior and a significant increase in the level of IL-1β in the hippocampus of mice,there was no significant difference in the time spent in the target quadrant or in the number of platform location crosses between LPS-treated and control groups in the probe trial testing.Conclusion Immune activation induced by LPS does not impair the retrieval of spatial memory.
