This study examined the effect of over-expression of sFlt-1 by trophoblasts on the barrier function of glomerular endothelial cells and the role of VEGF in this process in order to explore the pathogenesis of glomerul...This study examined the effect of over-expression of sFlt-1 by trophoblasts on the barrier function of glomerular endothelial cells and the role of VEGF in this process in order to explore the pathogenesis of glomerular disease in preeclampsia. SFlt-1 expression in the human trophoblasts （TEV-1 cells） was enhanced by transfecting sFlt-1 plasmid DNA into TEV-1 cells. The monolayer barrier fimction of glomerular endothelial cells （ciGEnCs） was determined by measuring the fluorescence intensity of bovine serum albumin （BSA） that crossed the monolayer of glomerular endothelial cells. The results showed that the over-expression of sFlt-1 by TEV-1 cells led to the barrier dysfunction of ciGEnCs, and the exogenous VEGF could alleviate the ciGEnCs dysfunction resulting from the over-expression of sFlt- 1 to a certain extent. It was concluded that the dysregulation of sFlt- 1 and VEGF in preeclamptic pregnancy may contribute to the barrier dysfunction of glomerular endothelial cells, and VEGF may play an important role in maintaining the barrier function of glomerular endothelial cells, but it may not be the sole factor.展开更多
AIM To investigate toll-like receptor 2(TLR2) and TLR4 expression, following bifidobacteria and low-dose EPEC endotoxin treatment, and intestinal barrier function in rat intestinal epithelial cell-18(IEC-18).METHODS S...AIM To investigate toll-like receptor 2(TLR2) and TLR4 expression, following bifidobacteria and low-dose EPEC endotoxin treatment, and intestinal barrier function in rat intestinal epithelial cell-18(IEC-18).METHODS Six experimental groups were established-normal control, EPEC, Bifidobacteria infantis(B. infantis), B. longum, B. bifidum, and B. youth groups. Optimal EPEC endotoxin concentration, bifidobacteria fold dilution, and treatment duration were determined. Quantitative real-time polymerase chain reaction and western blot, respectively, were conducted to detect TLR2 and TLR4 m RNA and protein expression in IEC-18 cells. Transepithelial electrical resistance(TEER) was measured by the EVOM chopstick voltohmmeter in each group. All experiments were conducted in triplicate and data were analyzed on SPSS 16.RESULTS TLR2 and TLR4 m RNA and protein expression in the EPEC group were significantly higher than in the control group(P < 0.05). TLR2 m RNA and protein expression in the B. infantis, B. longum and B. youth groups were significantly lower than in the normal control group(P < 0.05). TLR4 m RNA and protein expression in the B. bifidum and B. youth groups were significantly lower than in normal controls(P < 0.05). In addition, the TEER in B. infantis, B. longum, B. bifidum, and B. youth groups were decreased by 19%, 18%, 23% and 23%, respectively, after 120 min of intervention, as compared to the control group. However, the TEER in the EPEC group was significantly decreased by 67% in comparison to the normal control group(P < 0.05).CONCLUSION Bifidobacteria protect IEC-18 cells against injury by down-regulating TLR2 and TLR4 expression and enhance intestinal barrier function to protect the intestinal epithelial cells from pathogenic invasion.展开更多
Background: Alginate oligosaccharide(AOS), produced from alginate by alginate lyase-mediated depolymerisation, is a potential substitute for antibiotics and possesses growth-enhancing effects. Nevertheless, the mechan...Background: Alginate oligosaccharide(AOS), produced from alginate by alginate lyase-mediated depolymerisation, is a potential substitute for antibiotics and possesses growth-enhancing effects. Nevertheless, the mechanisms by which AOS regulates porcine growth remain to be elucidated. Therefore, we investigated the AOS-mediated changes in the growth performance of weaned pigs by determining the intestinal morphology, barrier function,as well as epithelium apoptosis.Methods: Twenty-four weaned pigs were distributed into two groups(n = 12) and received either a basal diet(control group) or the same diet supplemented with 100 mg/kg AOS. On d 15, D-xylose(0.1 g/kg body weight)was orally administrated to eight randomly selected pigs per treatment, and their serum and intestinal mucosa samples were collected 1 h later.Results: Our results showed that inclusion of AOS in the diet for 2 wk increased(P < 0.05) the average daily body weight gain in weaned pigs. Notably, AOS supplementation ameliorated the intestinal morphology and barrier function, as suggested by the enhanced(P < 0.05) intestinal villus height, secretory immunoglobulin A content and goblet cell counts. Compared to the control group, AOS ingestion both decreased(P < 0.05) the total apoptotic percentage and increased(P < 0.05) the proportion of S phase in the intestinal epithelial cells. Furthermore, AOS not only up-regulated(P < 0.05) the B-cell lymphoma-2(BCL2) transcriptional level but also down-regulated(P < 0.05) the B-cell lymphoma-2-associated X protein(BAX), cysteinyl aspartate-specific proteinase-3(caspase-3) and caspase-9 transcriptional levels in the small intestine.Conclusions: In summary, this study provides evidence that supplemental AOS beneficially affects the growth performance of weaned pigs, which may result from the improved intestinal morphology and barrier function,as well as the inhibited enterocyte death, through reducing apoptosis via mitochondria-dependent apoptosis.展开更多
This study examined the association of expression of vascular endothelial growth factor(VEGF),a promoter of angiogenesis,with endothelium dysfunction in preeclampsia.The level of VEGF protein and mRNA in the placenta ...This study examined the association of expression of vascular endothelial growth factor(VEGF),a promoter of angiogenesis,with endothelium dysfunction in preeclampsia.The level of VEGF protein and mRNA in the placenta and peripheral blood samples of 30 preeclampsia patients and 30 normotensive pregnant women was measured by immunohistochemistry,real-time reverse transcriptase-polymerase chain reaction(RT-PCR) and enzyme-linked immunosorbent assay(ELISA),respectively.VEGF expression in the human umbilical vein endothelial cells(HUVECs) was blocked by small interfering RNAs(siRNAs).The monolayer barrier function of HUVECs was determined by measuring the fluorescence intensity of BSA that crossed the HUVEC monolayers.The cell proliferation and cell-secreted nitric oxide(NO) level were detected by MTT method and nitrate reductase assay,respectively.The results showed that VEGF was expressed in the syncytiotrophoblasts and endothelial cells of vessels and capillaries in the placenta tissue.The serum level of VEGF in the preeclampsia patients was significantly decreased as compared with that in normal pregnant subjects,although VEGF mRNA expression in the placenta tissue of preeclampsia patients remained still high.Moreover,VEGF deficit could lead to endothelium cell dysfunction,and the administration of VEGF could protect endothelium cells from injury.It was concluded that lack of VEGF contributes to endothelium dysfunction,which may lead to the occurrence and development of preeclampsia.展开更多
Background: Endoplasmic reticulum(ER) stress is associated with multiple pathological processes of intestinal diseases. Despite a critical role of mechanistic target of rapamycin complex 1(m TORC1) in regulating cellu...Background: Endoplasmic reticulum(ER) stress is associated with multiple pathological processes of intestinal diseases. Despite a critical role of mechanistic target of rapamycin complex 1(m TORC1) in regulating cellular stress response, the crosstalk between m TORC1 and ER stress signaling and its contribution to the intestinal barrier function is unknown.Results: In the present study, we showed that intestinal epithelial cells(IEC-6) incubated with tunicamycin led to caspase-3-dependent apoptotic cell death. The induction of cell death was accompanied by activation of unfolded protein response as evidenced by increased protein levels for Bi P, p-IRE1α, p-e IF2α, p-JNK, and CHOP. Further study demonstrated that tunicamycin-induced cell death was enhanced by rapamycin, a specific inhibitor of m TORC1.Consistently, tunicamycin decreased transepithelial electrical resistance(TEER) and increased permeability of the cells. These effects of tunicamycin were exacerbated by m TORC1 inhibitor.Conclusions: Taken together, the data presented here identified a previously unknown crosstalk between an unfold protein response and m TORC1 signaling in the intestinal epithelium. This feed-back loop regulation on ER stress signaling by m TORC1 is critical for cell survival and intestinal permeability in epithelial cells.展开更多
Background： Cinnamicaldehyde（CA） is a key flavor compound in cinnamon essential oil possessing various bioactivities. Tight junction（TJ） proteins are vital for the maintenance of intestinal epithelial barrier fun...Background： Cinnamicaldehyde（CA） is a key flavor compound in cinnamon essential oil possessing various bioactivities. Tight junction（TJ） proteins are vital for the maintenance of intestinal epithelial barrier function,transport, absorption and utilization of dietary amino acids and other nutrients. In this study, we tested the hypothesis that CA may regulate the expression of TJ proteins and amino acid transporters in intestinal porcine epithelial cells（IPEC-1） isolated from neonatal pigs.Results： Compared with the control, cells incubated with 25 μmol/L CA had increased transepithelial electrical resistance（TEER） and decreased paracellular intestinal permeability. The beneficial effect of CA on mucosal barrier function was associated with enhanced protein abundance for claudin-4, zonula occludens（ZO）-1, ZO-2, and ZO-3. Immunofluorescence staining showed that 25 μmol/L CA promoted the localization of claudin-1 and claudin-3 to the plasma membrane without affecting the localization of other TJ proteins, including claudin-4, occludin,ZO-1, ZO-2, and ZO-3, compared with the control cells. Moreover, protein abundances for rBAT, xCT and LAT2 in IPEC-1 cells were enhanced by 25 μmol/L CA, while that for EAAT3 was not affected.Conclusions： CA improves intestinal mucosal barrier function by regulating the distribution of claudin-1 and claudin-3 in enterocytes, as well as enhancing protein abundance for amino acid transporters rBAT, xCT and LAT2 in enterocytes. Supplementation with CA may provide an effective nutritional strategy to improve intestinal integrity and amino acid transport and absorption in piglets.展开更多
Cell-cell and cell-matrix signaling and communication between adhesion sites involve mechanisms which are required for cellular functions during normal development and homeostasis; however these cellular functions and...Cell-cell and cell-matrix signaling and communication between adhesion sites involve mechanisms which are required for cellular functions during normal development and homeostasis; however these cellular functions and mechanisms are often deregulated in cancer. Aberrant signaling at cell-cell and cell-matrix adhesion sites often involves downstream mediators including Rho GTPases and tyrosine kinases. This review discusses these molecules as putative mediators of cellular crosstalk between cell-cell and cell-matrix adhesion sites, in addition to their attractiveness as therapeutic targets in cancer. Interestingly, inter-junctional crosstalk mechanisms are frequently typified by the way in which bacterial and viral pathogens opportunistically infect or intoxicate mammalian cells. This review therefore also discusses the concept of learning from pathogen-host interaction studies to better understand coordinated communication between cell-cell and cell-matrix adhesion sites, in addition to highlighting the potential therapeutic usefulness of exploiting pathogens or their products to tap into inter-junctional crosstalk. Taken together, we feel that increased knowledge around mechanisms of cell-cell and cell-matrix adhesion site crosstalk and consequently a greater understanding of their therapeutic targeting offers a unique opportunity to contribute to the emerging molecular revolution in cancer biology.展开更多
文摘This study examined the effect of over-expression of sFlt-1 by trophoblasts on the barrier function of glomerular endothelial cells and the role of VEGF in this process in order to explore the pathogenesis of glomerular disease in preeclampsia. SFlt-1 expression in the human trophoblasts （TEV-1 cells） was enhanced by transfecting sFlt-1 plasmid DNA into TEV-1 cells. The monolayer barrier fimction of glomerular endothelial cells （ciGEnCs） was determined by measuring the fluorescence intensity of bovine serum albumin （BSA） that crossed the monolayer of glomerular endothelial cells. The results showed that the over-expression of sFlt-1 by TEV-1 cells led to the barrier dysfunction of ciGEnCs, and the exogenous VEGF could alleviate the ciGEnCs dysfunction resulting from the over-expression of sFlt- 1 to a certain extent. It was concluded that the dysregulation of sFlt- 1 and VEGF in preeclamptic pregnancy may contribute to the barrier dysfunction of glomerular endothelial cells, and VEGF may play an important role in maintaining the barrier function of glomerular endothelial cells, but it may not be the sole factor.
基金Supported by Medjaden Academy and Research Foundation for Young Scientists,No.MJA20170410
文摘AIM To investigate toll-like receptor 2(TLR2) and TLR4 expression, following bifidobacteria and low-dose EPEC endotoxin treatment, and intestinal barrier function in rat intestinal epithelial cell-18(IEC-18).METHODS Six experimental groups were established-normal control, EPEC, Bifidobacteria infantis(B. infantis), B. longum, B. bifidum, and B. youth groups. Optimal EPEC endotoxin concentration, bifidobacteria fold dilution, and treatment duration were determined. Quantitative real-time polymerase chain reaction and western blot, respectively, were conducted to detect TLR2 and TLR4 m RNA and protein expression in IEC-18 cells. Transepithelial electrical resistance(TEER) was measured by the EVOM chopstick voltohmmeter in each group. All experiments were conducted in triplicate and data were analyzed on SPSS 16.RESULTS TLR2 and TLR4 m RNA and protein expression in the EPEC group were significantly higher than in the control group(P < 0.05). TLR2 m RNA and protein expression in the B. infantis, B. longum and B. youth groups were significantly lower than in the normal control group(P < 0.05). TLR4 m RNA and protein expression in the B. bifidum and B. youth groups were significantly lower than in normal controls(P < 0.05). In addition, the TEER in B. infantis, B. longum, B. bifidum, and B. youth groups were decreased by 19%, 18%, 23% and 23%, respectively, after 120 min of intervention, as compared to the control group. However, the TEER in the EPEC group was significantly decreased by 67% in comparison to the normal control group(P < 0.05).CONCLUSION Bifidobacteria protect IEC-18 cells against injury by down-regulating TLR2 and TLR4 expression and enhance intestinal barrier function to protect the intestinal epithelial cells from pathogenic invasion.
基金supported by the Special Fund for Agro-scientific Research in the Public Interest(201403047)
文摘Background: Alginate oligosaccharide(AOS), produced from alginate by alginate lyase-mediated depolymerisation, is a potential substitute for antibiotics and possesses growth-enhancing effects. Nevertheless, the mechanisms by which AOS regulates porcine growth remain to be elucidated. Therefore, we investigated the AOS-mediated changes in the growth performance of weaned pigs by determining the intestinal morphology, barrier function,as well as epithelium apoptosis.Methods: Twenty-four weaned pigs were distributed into two groups(n = 12) and received either a basal diet(control group) or the same diet supplemented with 100 mg/kg AOS. On d 15, D-xylose(0.1 g/kg body weight)was orally administrated to eight randomly selected pigs per treatment, and their serum and intestinal mucosa samples were collected 1 h later.Results: Our results showed that inclusion of AOS in the diet for 2 wk increased(P < 0.05) the average daily body weight gain in weaned pigs. Notably, AOS supplementation ameliorated the intestinal morphology and barrier function, as suggested by the enhanced(P < 0.05) intestinal villus height, secretory immunoglobulin A content and goblet cell counts. Compared to the control group, AOS ingestion both decreased(P < 0.05) the total apoptotic percentage and increased(P < 0.05) the proportion of S phase in the intestinal epithelial cells. Furthermore, AOS not only up-regulated(P < 0.05) the B-cell lymphoma-2(BCL2) transcriptional level but also down-regulated(P < 0.05) the B-cell lymphoma-2-associated X protein(BAX), cysteinyl aspartate-specific proteinase-3(caspase-3) and caspase-9 transcriptional levels in the small intestine.Conclusions: In summary, this study provides evidence that supplemental AOS beneficially affects the growth performance of weaned pigs, which may result from the improved intestinal morphology and barrier function,as well as the inhibited enterocyte death, through reducing apoptosis via mitochondria-dependent apoptosis.
文摘This study examined the association of expression of vascular endothelial growth factor(VEGF),a promoter of angiogenesis,with endothelium dysfunction in preeclampsia.The level of VEGF protein and mRNA in the placenta and peripheral blood samples of 30 preeclampsia patients and 30 normotensive pregnant women was measured by immunohistochemistry,real-time reverse transcriptase-polymerase chain reaction(RT-PCR) and enzyme-linked immunosorbent assay(ELISA),respectively.VEGF expression in the human umbilical vein endothelial cells(HUVECs) was blocked by small interfering RNAs(siRNAs).The monolayer barrier function of HUVECs was determined by measuring the fluorescence intensity of BSA that crossed the HUVEC monolayers.The cell proliferation and cell-secreted nitric oxide(NO) level were detected by MTT method and nitrate reductase assay,respectively.The results showed that VEGF was expressed in the syncytiotrophoblasts and endothelial cells of vessels and capillaries in the placenta tissue.The serum level of VEGF in the preeclampsia patients was significantly decreased as compared with that in normal pregnant subjects,although VEGF mRNA expression in the placenta tissue of preeclampsia patients remained still high.Moreover,VEGF deficit could lead to endothelium cell dysfunction,and the administration of VEGF could protect endothelium cells from injury.It was concluded that lack of VEGF contributes to endothelium dysfunction,which may lead to the occurrence and development of preeclampsia.
基金supported the National Natural Science Foundation of China(No.31272451,31272450,31572410)Chinese University Scientific Fund(2015DK001)+3 种基金the 111 Project(B16044)the Program for New Century Excellent Talents in University(NCET-12-0522)the Agriculture and Food Research Initiative Competitive Grant from the USDA National Institute of Food and Agriculture(No.2014–67015-21770)Texas A&M Agri Life Research(H-8200)
文摘Background: Endoplasmic reticulum(ER) stress is associated with multiple pathological processes of intestinal diseases. Despite a critical role of mechanistic target of rapamycin complex 1(m TORC1) in regulating cellular stress response, the crosstalk between m TORC1 and ER stress signaling and its contribution to the intestinal barrier function is unknown.Results: In the present study, we showed that intestinal epithelial cells(IEC-6) incubated with tunicamycin led to caspase-3-dependent apoptotic cell death. The induction of cell death was accompanied by activation of unfolded protein response as evidenced by increased protein levels for Bi P, p-IRE1α, p-e IF2α, p-JNK, and CHOP. Further study demonstrated that tunicamycin-induced cell death was enhanced by rapamycin, a specific inhibitor of m TORC1.Consistently, tunicamycin decreased transepithelial electrical resistance(TEER) and increased permeability of the cells. These effects of tunicamycin were exacerbated by m TORC1 inhibitor.Conclusions: Taken together, the data presented here identified a previously unknown crosstalk between an unfold protein response and m TORC1 signaling in the intestinal epithelium. This feed-back loop regulation on ER stress signaling by m TORC1 is critical for cell survival and intestinal permeability in epithelial cells.
基金supported the National Natural Science Foundation of China(31572410,31572412,31625025)the 111 Project(B16044)+2 种基金the Program for New Century Excellent Talents in University(NCET-12-0522)the Agriculture and Food Research Initiative Competitive Grant from the USDA National Institute of Food and Agriculture(No.2014-6701521770)Texas A&M Agri Life Research(H-8200)
文摘Background： Cinnamicaldehyde（CA） is a key flavor compound in cinnamon essential oil possessing various bioactivities. Tight junction（TJ） proteins are vital for the maintenance of intestinal epithelial barrier function,transport, absorption and utilization of dietary amino acids and other nutrients. In this study, we tested the hypothesis that CA may regulate the expression of TJ proteins and amino acid transporters in intestinal porcine epithelial cells（IPEC-1） isolated from neonatal pigs.Results： Compared with the control, cells incubated with 25 μmol/L CA had increased transepithelial electrical resistance（TEER） and decreased paracellular intestinal permeability. The beneficial effect of CA on mucosal barrier function was associated with enhanced protein abundance for claudin-4, zonula occludens（ZO）-1, ZO-2, and ZO-3. Immunofluorescence staining showed that 25 μmol/L CA promoted the localization of claudin-1 and claudin-3 to the plasma membrane without affecting the localization of other TJ proteins, including claudin-4, occludin,ZO-1, ZO-2, and ZO-3, compared with the control cells. Moreover, protein abundances for rBAT, xCT and LAT2 in IPEC-1 cells were enhanced by 25 μmol/L CA, while that for EAAT3 was not affected.Conclusions： CA improves intestinal mucosal barrier function by regulating the distribution of claudin-1 and claudin-3 in enterocytes, as well as enhancing protein abundance for amino acid transporters rBAT, xCT and LAT2 in enterocytes. Supplementation with CA may provide an effective nutritional strategy to improve intestinal integrity and amino acid transport and absorption in piglets.
基金Supported by Past and present funding in the senior author’s laboratory as follows--Health Research Board of Ireland(HRA--POR-2014-545HRA/2009/49+6 种基金RP/2006/95,to Hopkins AM)Science Foundation Ireland(13/IA/19942008/RFP/NSC14272008/RFP/NSC1427 TIDA Feasibility 10,to Hopkins AM)Cancer Research Ireland,Breast Cancer IrelandBrazil Science Without Borders(CAPES-13306-13-8)the Beaumont Hospital Cancer Research and Development Trust
文摘Cell-cell and cell-matrix signaling and communication between adhesion sites involve mechanisms which are required for cellular functions during normal development and homeostasis; however these cellular functions and mechanisms are often deregulated in cancer. Aberrant signaling at cell-cell and cell-matrix adhesion sites often involves downstream mediators including Rho GTPases and tyrosine kinases. This review discusses these molecules as putative mediators of cellular crosstalk between cell-cell and cell-matrix adhesion sites, in addition to their attractiveness as therapeutic targets in cancer. Interestingly, inter-junctional crosstalk mechanisms are frequently typified by the way in which bacterial and viral pathogens opportunistically infect or intoxicate mammalian cells. This review therefore also discusses the concept of learning from pathogen-host interaction studies to better understand coordinated communication between cell-cell and cell-matrix adhesion sites, in addition to highlighting the potential therapeutic usefulness of exploiting pathogens or their products to tap into inter-junctional crosstalk. Taken together, we feel that increased knowledge around mechanisms of cell-cell and cell-matrix adhesion site crosstalk and consequently a greater understanding of their therapeutic targeting offers a unique opportunity to contribute to the emerging molecular revolution in cancer biology.
