Induction of endothelin-1 synthesis by IL-2 and its modulation of rat intestinal epithelial cell growth

1998 ◽  
Vol 275 (3) ◽  
pp. G556-G563 ◽  
Author(s):  
Takeharu Shigematsu ◽  
Soichiro Miura ◽  
Masahiko Hirokawa ◽  
Ryota Hokari ◽  
Hajime Higuchi ◽  
...  

Endothelin (ET), a vasoconstrictive peptide, is known to have a variety of biological actions. Although ET is released by vascular endothelial cells, other cell populations also have been reported to synthesize and release ET. In this study, we examined whether ET is synthesized by intestinal epithelial cells and whether it affects induction of epithelial cell proliferation by interleukin-2 (IL-2). Subconfluent monolayers of intestinal epithelial cells (IEC-6 and IEC-18) were maintained in serum-free medium before addition of rat IL-2. Both IEC-6 and IEC-18 cells released ET-1 into the medium under unstimulated conditions, as determined by a sandwich ELISA. IL-2 significantly enhanced ET-1 release in a time-dependent manner. ET-3 was not detectable in the culture media of either cell line. Expression of ET-1 and ET-3 mRNA in epithelial cells was assessed by competitive PCR. Both cell lines were shown to express ET-1 mRNA, but no ET-3 mRNA was detected. IL-2 treatment enhanced ET-1 mRNA expression by both IEC-6 and IEC-18 cells. Both cell lines also expressed mRNA for ETA and ETB receptor subtypes. When cell proliferation was assessed, exogenous ET-1 induced a slight proliferative response in both types of cells that was consistent and significant at low ET-1 concentrations; cell growth was inhibited at a higher concentration (10−7M). IL-2 produced a significant proliferative response in both cell lines. However, the addition of ET-1 (10−7 M) to culture media attenuated the IL-2-induced increase in cell proliferation. ETA-receptor antagonists significantly enhanced cellular proliferation, suggesting involvement of the ETA receptor in modulation of IL-2-induced intestinal epithelial cell growth.

2020 ◽  
Vol 98 (Supplement_3) ◽  
pp. 187-187
Author(s):  
Lauren Kovanda ◽  
Zhiliang Fan ◽  
Xunde Li ◽  
Yanhong Liu

Abstract A novel method has been developed to easily hydrolyze cellulose to sodium cellobionate in a filamentous fungas, Neurospora crassa. The objectives of this experiment were to investigate the in vitro biological activities of sodium cellobionate. Antioxidant activity was evaluated with 3 chemical-based assays, including DPPH radical scavenging assay (DPPH), Trolox equivalent antioxidant capacity assay (TEAC), and ferric reducing antioxidant power assay (FRAP). Antimicrobial activity was determined as minimum inhibitory concentration (MIC) that prevented growth of tested bacteria, including four gram-negative bacteria (Escherichia coli F18 and ATCC 25922, and Salmonella Typhimurium ATCC 14028 and a wild strain isolated from cull diary cows in California) and one gram-positive bacteria (Enterococcus faecalis ATCC 29212). Anti-inflammatory activity was tested by analyzing TNF-α production with porcine alveolar macrophages that were challenged with lipopolysaccharide. A porcine intestinal epithelial cell line, IPEC-J2, was also used to test the effects of cellobionate on cell proliferation of intestinal epithelial cells. The tested doses of sodium cellobionate were 0, 0.04, 0.20, 1.00, 2.00, 4.00, 20.00, and 40.00 mg/mL. All assays were performed with over 6 replicates, except that MIC assays were performed as triplicate. All data were analyzed by PROC MIXED of SAS. Sodium cellobionate did not have radical scavenging capacity, but had weak FRAP (9.68 μM L-Cysteine equivalent) and TEAC (69% reduction) at the dose of 40 mg/mL. MIC results revealed that sodium cellobionate did not inhibit the growth of all tested bacteria, indicating it does not have antimicrobial activity within the range of tested doses. Sodium cellobionate did not exhibit anti-inflammatory activities, but significantly enhanced (P < 0.05) intestinal epithelial cell proliferation in vitro by 24.00%, 39.64%, and 25.98% when the doses were 1.00, 2.00, and 4.00 mg/mL, respectively. Results of this experiment indicate that cellobionate has limited biological activities in vitro, except that this biomass product could strongly stimulate the proliferation of intestinal epithelial cells. Future research will focus on the potential impacts of sodium cellobionate on intestinal physiology in vivo.


2012 ◽  
Vol 19 (4) ◽  
pp. 603-608 ◽  
Author(s):  
Yujun Jiang ◽  
Xuena Lü ◽  
Chaoxin Man ◽  
Linlin Han ◽  
Yi Shan ◽  
...  

ABSTRACTIntestinal epithelial cells can respond to certain bacteria by producing an array of cytokines and chemokines which are associated with host immune responses.Lactobacillus acidophilusNCFM is a characterized probiotic, originally isolated from human feces. This study aimed to test the ability ofL. acidophilusNCFM to stimulate cytokine and chemokine production in intestinal epithelial cells and to elucidate the mechanisms involved in their upregulation. In experiments using intestinal epithelial cell lines and mouse models, we observed thatL. acidophilusNCFM could rapidly but transiently upregulate a number of effector genes encoding cytokines and chemokines such as interleukin 1α (IL-1α), IL-1β, CCL2, and CCL20 and that cytokines showed lower expression levels withL. acidophilusNCFM treatment than chemokines. Moreover,L. acidophilusNCFM could activate a pathogen-associated molecular pattern receptor, Toll-like receptor 2 (TLR2), in intestinal epithelial cell lines. The phosphorylation of NF-κB p65 and p38 mitogen-activated protein kinase (MAPK) in intestinal epithelial cell lines was also enhanced byL. acidophilusNCFM. Furthermore, inhibitors of NF-κB (pyrrolidine dithiocarbamate [PDTC]) and p38 MAPK (SB203580) significantly reduced cytokine and chemokine production in the intestinal epithelial cell lines stimulated byL. acidophilusNCFM, suggesting that both NF-κB and p38 MAPK signaling pathways were important for the production of cytokines and chemokines induced byL. acidophilusNCFM.


2003 ◽  
Vol 71 (6) ◽  
pp. 3503-3511 ◽  
Author(s):  
Manabu Suzuki ◽  
Tadakazu Hisamatsu ◽  
Daniel K. Podolsky

ABSTRACT Although some intestinal epithelial cell lines are known to respond to lipopolysaccharide (LPS), understanding of the relationship between LPS responsiveness and the expression of LPS receptors or factors regulating LPS responsiveness of intestinal epithelial cell lines is incomplete. In this study, we demonstrate that commonly studied human intestinal epithelial cell lines can be classified into at least three different types on the basis of LPS responsiveness, Toll-like receptor-4 (TLR4) expression, and the effects of gamma interferon (IFN-γ) on LPS responsiveness. The first phenotype, which includes the HCT-116 and Caco-2 cell lines, is characterized by relative hyporesponsiveness to LPS and diminished expression of TLR4 protein. In these cells, IFN-γ does not induce LPS responsiveness. The second phenotype, which includes cell line SW480, exhibits a highly LPS-responsive phenotype and surface expression of TLR4 protein even in unprimed conditions. These lines are functionally similar to cells of monocytic lineage. In the third phenotype, which includes the HT-29 and Colo205 cell lines, TLR4 protein is largely present in the cytoplasmic fraction and the cells are hyporesponsive to LPS in an unprimed condition. However, priming of these cells with IFN-γ can induce LPS responsiveness through augmentation of LPS uptake and expression of MD-2 mRNA and intracellular TLR4 proteins. Finally, these findings suggest that the Th1 cytokine IFN-γ modulates LPS responsiveness through several mechanisms in intestinal epithelial cells and that these cells may comprise different subpopulations with distinct roles in innate immune responses.


1995 ◽  
Vol 182 (4) ◽  
pp. 1079-1088 ◽  
Author(s):  
Y Li ◽  
X Y Yio ◽  
L Mayer

The activation of CD8+ suppressor T cells by normal intestinal epithelial cells in antigen-specific or allogeneic mixed cell culture systems has significant implications for the regulation of mucosal immune responses. In this study, we found that the capacity of epithelial cells to induce CD8+ suppressor T cell activation appeared to be linked to the binding of CD8 molecules on the T cell surface. This appears to be mediated by a non-class I molecule expressed on the epithelial cell surface, which binds to CD8 and results in the activation of the CD8-associated src-like tyrosine kinase, p56lck. Epithelial cell-stimulated p56lck activation is an early event (in contrast to monocytes) and is essential for T cell activation, since proliferation could be completely abrogated by pretreatment of T cells with genestein or herbamycin, both of which are protein tyrosine kinase inhibitors. Pretreatment of T cells with anti-CD8 or of intestinal epithelial cells with an anti-epithelial cell mAb B9 inhibited p56lck activation and further confirmed that CD8 on the T cell and a CD8 ligand on the epithelial cell were involved in this T cell activation event. The specificity of this reaction was confirmed in experiments in which murine transfectants 3G4 and 3G8, expressing CD4 or CD8, respectively, were used. Coculture of 3G8 with epithelial cells but not with monocytes activated p56lck in this cell line, whereas p56lck was preferentially activated in 3G4 cells when monocytes were used as the stimulator cells. Although stimulation through CD8- and CD8-associated p56lck was important for epithelial cell-induced T cell activation, T cell proliferation could not be induced by cross-linking CD8 alone with monoclonal antibody anti-CD8. These data suggest that a second signal, possibly through the T cell antigen receptor since activation of the T cell receptor-associated kinase fyn was also seen, is required for epithelial cell-driven T cell proliferation.


2012 ◽  
Vol 303 (3) ◽  
pp. G356-G366 ◽  
Author(s):  
Steven H. Young ◽  
Nora Rozengurt ◽  
James Sinnett-Smith ◽  
Enrique Rozengurt

We have examined the role of protein kinase D1 (PKD1) signaling in intestinal epithelial cell migration. Wounding monolayer cultures of intestinal epithelial cell line IEC-18 or IEC-6 induced rapid PKD1 activation in the cells immediately adjacent to the wound edge, as judged by immunofluorescence microscopy with an antibody that detects the phosphorylated state of PKD1 at Ser916, an autophosphorylation site. An increase in PKD1 phosphorylation at Ser916 was evident as early as 45 s after wounding, reached a maximum after 3 min, and persisted for ≥15 min. PKD1 autophosphorylation at Ser916 was prevented by the PKD family inhibitors kb NB 142-70 and CRT0066101. A kb NB 142-70-sensitive increase in PKD autophosphorylation was also elicited by wounding IEC-6 cells. Using in vitro kinase assays after PKD1 immunoprecipitation, we corroborated that wounding IEC-18 cells induced rapid PKD1 catalytic activation. Further results indicate that PKD1 signaling is required to promote migration of intestinal epithelial cells into the denuded area of the wound. Specifically, treatment with kb NB 142-70 or small interfering RNAs targeting PKD1 markedly reduced wound-induced migration in IEC-18 cells. To test whether PKD1 promotes migration of intestinal epithelial cells in vivo, we used transgenic mice that express elevated PKD1 protein in the small intestinal epithelium. Enterocyte migration was markedly increased in the PKD1 transgenic mice. These results demonstrate that PKD1 activation is one of the early events initiated by wounding a monolayer of intestinal epithelial cells and indicate that PKD1 signaling promotes the migration of these cells in vitro and in vivo.


2021 ◽  
Author(s):  
Yiyun Deng ◽  
Zhe Zhang ◽  
Yuanyuan Hong ◽  
Lijuan Feng ◽  
Yong Su ◽  
...  

Abstract Objectives: The gastrointestinal side effects of mycophenolic acid affect its efficacy in kidney transplant patients, which may be due to its toxicity to the intestinal epithelial mechanical barrier, including intestinal epithelial cell apoptosis and destruction of tight junctions. The toxicity mechanism of mycophenolic acid is related to oxidative stress-mediated the activation of mitogen-activated protein kinases (MAP K). Schisandrin A (Sch A), one of the main active components of the Schisandra chinensis, can protects intestinal epithelial cells from deoxynivalenol-induced cytotoxicity and oxidative damage by antioxidant effects. The aim of this study was to investigate the protective effect and potential mechanism of Sch A on mycophenolic acid-induced damage in intestinal epithelial cell. Methods: Caco-2 cells monolayers were treated with mycophenolic acid (10µM) and/or Sch A (10, 20 and 40µM) at 37°C for 24h, and cell viability was measured by MTT; Western blot and immunofluorescence were used to detect the expression of relevant proteins. Intracellular ROS and apoptosis were measured by flow cytometry, and malondialdehyde (MDA) and superoxide dismutase (SOD) levels were measured by kits. Results: The results showed that Sch A significantly reversed the mycophenolic acid-induced cell viability reduction, restored the expression of tight junction protein ZO-1, occludin and reduced cell apoptosis. In addition, Sch A inhibited mycophenolic acid-mediated MAPK activation and reactive oxygen species (ROS) increase. Conclusions: Sch A protected intestinal epithelial cells from mycophenolic acid intestinal toxicity, at least in part, by reducing oxidative stress and inhibiting MAPK signaling pathway. Conclusions: Sch A protected intestinal epithelial cells from mycophenolic acid intestinal toxicity, at least in part, by reducing oxidative stress and inhibiting MAPK signaling pathway.


2007 ◽  
Vol 292 (4) ◽  
pp. G958-G963 ◽  
Author(s):  
Troy A. Markel ◽  
Paul R. Crisostomo ◽  
Meijing Wang ◽  
Christine M. Herring ◽  
Tim Lahm ◽  
...  

Bacteria have developed mechanisms to sequester host iron via chelators such as deferoxamine (DFO). Interestingly, DFO has been shown to stimulate acute intestinal epithelial cell inflammatory cytokine production in the absence of bacteria; however, this mechanism has not been elucidated. Intestinal epithelial cell production of IL-6 and TNF-α is elevated in various gastrointestinal pathologies, including acute intestinal ischemia. Similarly, VEGF and HGF are essential to intestinal epithelial cell integrity. Therapeutic strategies that decrease IL-6 and TNF-α while increasing VEGF and HGF therefore have theoretical appeal. We hypothesized that 1) fetal human intestinal epithelial cells acutely produce increased IL-6, TNF-α, VEGF, and HGF during iron chelation and 2) the MAPK pathway mediates these effects. Fetal human intestinal epithelial cells were stimulated by iron chelation (1 mM DFO) with and without p38 MAPK, ERK, or JNK inhibition. Supernatants were harvested after 24 h of incubation, and IL-6, TNF-α, VEGF, and HGF levels were quantified by ELISA. Activation of MAPK pathways was confirmed by Western blot analysis. DFO stimulation resulted in a significant increase in epithelial cell IL-6 and VEGF production while yielding a decrease in HGF production ( P < 0.05). Unexpectedly, TNF-α was not detectable. p38 MAPK, ERK, and JNK inhibition significantly decreased IL-6, VEGF, and HGF production ( P < 0.05). In conclusion, DFO acutely increases fetal human intestinal epithelial cell IL-6 and VEGF expression while causing an unexpected decrease in HGF expression and no detectable TNF-α production. Furthermore, chelator-induced intestinal epithelial cell cytokine expression depends on p38, ERK, and JNK MAPK pathways.


1997 ◽  
Vol 273 (4) ◽  
pp. C1168-C1175 ◽  
Author(s):  
Lucio Gama ◽  
Lynn M. Baxendale-Cox ◽  
Gerda E. Breitwieser

Expression of Ca2+-sensing receptors (CaR) was demonstrated in several human intestinal epithelial cell lines (T84, HT-29, and Caco-2) and in rat intestinal epithelium by both reverse transcriptase-polymerase chain reaction (PCR) and Northern blotting of RNA. Restriction patterns of the PCR products were of the sizes predicted by the human and rat sequences. CaR agonists (Ca2+, poly-l-arginine, protamine) mediated an increase in intracellular Ca2+ in HT-29–18-C1 cells (monitored by changes in fura 2 fluorescence), which was dependent on release from thapsigargin-sensitive stores. U-73122, an inhibitor of phosphatidylinositol-phospholipase C, eliminated the CaR agonist-mediated rise in intracellular Ca2+, whereas its inactive analog, U-73343, had no effect. Pertussis toxin pretreatment had no effect on CaR agonist-mediated modulation of intracellular Ca2+. Taken together, these studies demonstrate that CaR are expressed in intestinal epithelial cells and couple to mobilization of intracellular Ca2+. The presence of CaR in intestinal epithelial cells presents a new locus for investigations into the role(s) of extracellular Ca2+ in modulating intestinal epithelial cell differentiation and transepithelial Ca2+ transport.


2005 ◽  
Vol 288 (2) ◽  
pp. G346-G353 ◽  
Author(s):  
Laetitia Charrier ◽  
Yutao Yan ◽  
Adel Driss ◽  
Christian L. Laboisse ◽  
Shanthi V. Sitaraman ◽  
...  

The disintegrin metalloproteases (or ADAMs) are membrane-anchored glycoproteins that have been implicated in cell-cell or cell-matrix interactions and in proteolysis of molecules on the cell surface. The expression and/or the pathophysiological implications of ADAMs are not known in intestinal epithelial cells. Therefore, our aim was to investigate the expression and the role of ADAMs in intestinal epithelial cells. Expression of ADAMs was assessed by RT-PCR, Western blot analysis, and immunufluorescence experiments. Wound-healing experiments were performed by using the electric cell substrate impedence sensing technology. Our results showed that ADAMs-10, -12, and -15 mRNA are expressed in the colonic human cell lines Caco2-BBE and HT29-Cl.19A. An ADAM-15 complementary DNA cloned from Caco2-BBE poly(A)+ RNA, and encompassing the entire coding region, was found to be shorter and to present a different region encoding the cytoplasmic tail compared with ADAM-15 sequence deposited in the database. In Caco2-BBE cells and colonic epithelial cells, ADAM-15 protein was found in the apical, basolateral, and intracellular compartments. We also showed that the overexpression of ADAM-15 reduced cell migration in a wound-healing assay in Caco2-BBE monolayers. Our data show that 1) ADAM-15 is expressed in human intestinal epithelia, 2) a new variant of ADAM-15 is expressed in a human intestinal epithelial cell line, and 3) ADAM-15 is involved in intestinal epithelial cells wound-healing processes. Together, these results suggest that ADAM-15 may have important pathophysiological roles in intestinal cells.


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