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Mo1109 Immune Regulation of the Intestinal Progenitor Cell Microenvironment
response to H. pylori infection. Methods: Mice expressing a parietal cell-specific deletion of Shh (PC-ShhKO) and controls were infected with H. pylori. Gastric Shh, cytokine and chemokine expression was assayed by qRT-PCR or by a Luminex®-based multiplex assay 2, 7 and 180 days post-inoculation. Circulating Shh concentrations were assayed by ELISA. To identify the direct role of Shh signaling in macrophage recruitment to the stomach, we performed bone marrow chimera experiments using mice with a myeloid cell-specific deletion of Hedgehog signal transduction protein smoothened (LyzsCre/SmoKO). Macrophage recruitment in response to H. pylori was measured in both gastric tissue and peripheral blood by fluorescence-activated cell sorting (FACS). Results: 1) H. pylori-infected PC-ShhKO mice fail to develop gastritis: Control mice infected with H. pylori for 6 months developed a significant inflammatory response that was documented by CD4+ T-lymphocyte infiltration and elevation of pro-inflammatory cytokines IFNγ and IL-1β in the stomach. PC-ShhKO mice did not develop gastric inflammation even after 6 months of H. pylori infection. In control stomachs Shh expression was induced within 7 days post-infection. 2) Gastric Shh acts as a macrophage chemoattractant in response to H. pylori infection: Control mice exhibited elevated concentrations of the neutrophil chemoattractant KC, a murine IL-8 homologue, monocyte chemotactic protein-1 (MCP-1) and circulating Shh concentrations that were accompanied by the recruitment of CD11b+F4/80+Ly6Chigh macrophages 48 hours post-infection. Control recipient mice transplanted with bone marrow from control animals exhibited an influx of CD11b+F4/ 80+Ly6Chigh macrophages to the gastric mucosa that was accompanied by a significant decrease in the number of macrophages in the periphery. H. pylori-infected control recipient mice transplanted with LyzsCre/SmoKO bone marrow donor cells showed an absence of CD11b+F4/80+Ly6Chigh macrophage recruitment. Conclusion: During the innate immune response H. pylori-induced Shh released from the stomach acts as a macrophage chemoattractant to play a role in the initiation of gastritis. Loss of Shh, as observed during gastritis, may result in the disruption of a sufficient immune mechanism necessary to eradicate bacterial infection, and thus allowing the development of H. pylori-induced chronic inflammation.
Mo1107 Progastrin Inhibits the Homotypic Fusion Between Human Macrophages Carlos Hernandez, Dolores Ortiz-Masia, Dolores Barrachina, SARA CALATAYUD Macrophages have the ability to undergo homotypic fusion and generate multinucleated cells in chronic inflammatory processes with the participation of IL4. Macrophages can also fuse heterotypically with cancer cells, which could gain the ability to migrate and induce metastasis through this process (Cancer Metastasis Rev 2010, 29:695; Cancer Res 2009, 69:8536). The molecular mechanisms implicated in both processes seem to be similar (Nat Rev Cancer 2008, 8:377). We studied the effects of progastrin on macrophages because colonic tumors synthesize progastrin and macrophages express annexin-II, a molecule that serves as progastrin receptor. In the present study we report the serendipitous finding of an inhibitory effect of progastrin on macrophage fusion. The effects of progastrin were analyzed on macrophages derived from human peripheral blood monocytes. Macrophages were treated with progastrin (10-9-10-7M) or its vehicle in the presence of: 1) E.coli LPS (1μg/ml) plus IFNγ (20ng/ml), 24h, to induce pro-inflammatory macrophages (M1); 2) IL4 (20ng/ml, 48h) to induce tolerogenic macrophages (M2a); or 3) IL10 (20ng/ml, 48 h) to induce anti-inflammatory macrophages (M2c). Macrophages were incubated with hoescht to identify the nuclei and with fluorescent labeled Ab against the surface molecules CD86 (M1) and CD206 (M2a, M2c). Fluorescence was analyzed with the software for static cytometry ScanR (>5000 cells/well). Hoescht fluorescence was used to record the spatial disposition of cells, distinguishing between isolated and aggregated/multinucleated cells. The analysis of the fluorescence emitted by the surface markers allowed us to discriminate between independent cells in close proximity and multinucleated cells. All activation treatments induced a slight reduction in the number of cells per area (LPS+IFNγ: 93±3, IL4: 90±2, IL10: 97±3 % of control values) which was not modified by cotreatment with progastrin (10-7M; 90±4%, 90±2% and 87±7% respectively). The cytometric analysis detected the presence of spontaneously generated multinucleated formations including 3-10 nuclei (mean: 3.4±0.2). IL4 significantly increased the number of these formations (142± 6 %, p<0.05 vs control values). IL10 did not induce any significant change (94±8%) while LPS+IFNγ significantly reduced its presence (70±7%, p<0.05 vs control values). Co-treatment with progastrin significantly reduced macrophage fusion in all cases (see figure). None of these treatments induced a significant effect in the mean size of these multinucleated forms. Our results indicate that progastrin inhibits macrophage fusion. This effect takes place independently of the pattern of macrophage activation. We hypothesized that, if this inhibitory effect of progastrin is also effective against macrophage fusion with cancer cells, the peptide may constitute a neutralizing force against metastasis.
Mo1109 Immune Regulation of the Intestinal Progenitor Cell Microenvironment Tim Vanuytsel, Luigi Notari, Shu Yan, Aiping Zhao, Jennifer A. Bohl, Leon McLean, Rex Sun, Joseph F. Urban, Allen Smith, Jan F. Tack, Terez Shea-Donohue Background: The gastrointestinal tract is the largest interface between the external and internal milieux. To adapt to different environmental challenges, the epithelium renews every 5 to 7 days. Enteric infections induce a proliferative response in the colon; however, knowledge of how different cytokine profiles in the stem-cell microenvironment influence progenitor cell proliferation and migration is limited. Aim: To elucidate the effect of different cytokine microenvironments on intestinal progenitor cells. Materials and methods: C57BL/ 6 mice (N=25) were infected with Citrobacter rodentium (Cr), a model for enterotoxigenic E. coli, by oral gavage of 1010 CFU and studied every week (n=5/group) for 4 weeks post infection (PI). BALB/c and STAT6 knockout (KO) (N=20/group) were infected with the cecal-dwelling Trichuris muris, a model for human whipworm, by gavage of 200 embryonated eggs and studied every week (n=5/group) for 4 weeks. All mice were injected with 10mg bromodeoxyuridine (BrdU) 2 hours before sacrifice. Colonic segments were processed for histology and gene expression. BrdU positive cells per crypt were counted and the mucosal height measured in >10 well-oriented crypts/mouse. Gene expression of IFNγ (Th1), IL17A (Th17), IL4 and IL13 (Th2) and CXCL10 was quantified by real-time PCR. Results: Cr upregulated IFNγ and IL17A, cytokines needed for Cr clearance by day 14 PI (Table 1) coinciding with a proliferative response of the colonic epithelium indicated by an increase in the number of BrdU positive cells per crypt (13.9±1.6 vs. 5.2±0.7; p<0.01) and in mucosal height (191±6 vs. 119±6 μm; p<0.01). In WT T. muris infected mice , the maximal increase of IL4 and IL13, cytokines needed for clearance, occured at day 14 PI and coincided with a modest upregulation of IFNγ and CXCL10 (Table 1). At this time there was also a transient increase in BrdU positive cells per crypt (11±0.6 vs. 4.9±0.3; p<0.01) and mucosal height (131±10 vs. 97±2 μm; p<0.01) preceding clearance. In contrast, day 14 PI STAT6 KO mice lacked upregulation of Th2 or Th1 cytokines or increased epithelial proliferation despite the presence of worms. These mice develop a chronic infection with a proliferative response at day 28 PI that also coincides with the generation of a Th1 predominant response (Table 1) and CXCL10 upregulation. Conclusion: By manipulating the colon cytokine microenvironment with two polarized infections in different backgrounds, we showed that the maximal proliferative response coincides with the mounting of a Th1 cytokine response and production of CXCL10. The latter is upregulated in IBD-patients and is a well-known inhibitor of epithelial cell migration which leads to crypt hyperplasia in the presence of proliferation (Cliffe et al. 2005). Our findings provide further insight in the immuneregulation of the progenitor cell microenvironment of the colon.
Effect of progastrin on macrophage fusion. * p<0.05 vs corresponding control group (RMANOVA + Newman-Keuls test). Mo1108
Changes in gene-expression of cytokines during enteric infections. Data expressed as average fold-change±SEM. #p<0.05; *p<0.01
Gastric Sonic Hedgehog Acts as a Macrophage Chemoattractant During the Development of the Immune Response to Helicobacter pylori Infection Michael A. Schumacher, Jessica M. Donnelly, Amy C. Engevik, Chang Xiao, Li Yang, Susan H. Kenny, Andrea Varro, Frederic Hollande, Linda C. Samuelson, Yana Zavros Background: Macrophages are essential innate responders to Helicobacter pylori (H. pylori)derived signals from the epithelium that are crucial to the development of gastritis. Sonic Hedgehog (Shh), a regulator of gastric epithelial differentiation and function, is known to regulate the host gastric immune response, but the precise nature of its role is unknown. Hypothesis: Gastric Shh acts as a macrophage chemoattractant during the innate immune
S-597
AGA Abstracts
AGA Abstracts
In addition, TNFα protein release in the conditioned media was measured with an enzymelinked immunosorbent assay (ELISA). KB-R7785(10μM) was used to inhibit ADAMs' activities. RNA interference was performed to knock down endogenous ADAM 17 and AREGregulating protein(ARP) 36. The association of ARP36 with ADAM17 was analyzed with IP with anti-ARP36 antibody followed by western blotting(WB) with anti-ADAM17 antibody. Results: The membrane protein immunoprecipitated with anti-proAREG antibody was identified as ARP36 with MALDI/TOFMS analysis. ELISA and AP assay showed IL-1β-induced TNFα shedding in HCT116 and HT29 cells and that TPA did TNFα shedding in U937 cells within 5 hrs. KB-R7785 and depletion of ADAM17 significantly blocked TNFα shedding with IL-1β and TPA. Depletion of ARP36 significantly inhibited TNFα shedding with IL1β and TPA in ELISA and AP assay. On the other hand knockdown of ARP36 did not abrogate the shedding of AREG and HB-EGF for which ADAM17 is responsible. IP and WB showed the association of ARP36 with ADAM17. Conclusions: ADAM17 is closely associated with APR36. ADAM17 is involved in IL-1β-induced TNFα shedding in colon epithelial cells and TPA-induced TNFα shedding in monocytes. ARP36 plays an important role on TNF shedding with IL-1β and TPA. Inhibition of ARP36 may be a new therapeutic strategy for prevention of TNFα shedding during IBD inflammation.
Mo1107 Progastrin Inhibits the Homotypic Fusion Between Human Macrophages Carlos Hernandez, Dolores Ortiz-Masia, Dolores Barrachina, SARA CALATAYUD Macrophages have the ability to undergo homotypic fusion and generate multinucleated cells in chronic inflammatory processes with the participation of IL4. Macrophages can also fuse heterotypically with cancer cells, which could gain the ability to migrate and induce metastasis through this process (Cancer Metastasis Rev 2010, 29:695; Cancer Res 2009, 69:8536). The molecular mechanisms implicated in both processes seem to be similar (Nat Rev Cancer 2008, 8:377). We studied the effects of progastrin on macrophages because colonic tumors synthesize progastrin and macrophages express annexin-II, a molecule that serves as progastrin receptor. In the present study we report the serendipitous finding of an inhibitory effect of progastrin on macrophage fusion. The effects of progastrin were analyzed on macrophages derived from human peripheral blood monocytes. Macrophages were treated with progastrin (10-9-10-7M) or its vehicle in the presence of: 1) E.coli LPS (1μg/ml) plus IFNγ (20ng/ml), 24h, to induce pro-inflammatory macrophages (M1); 2) IL4 (20ng/ml, 48h) to induce tolerogenic macrophages (M2a); or 3) IL10 (20ng/ml, 48 h) to induce anti-inflammatory macrophages (M2c). Macrophages were incubated with hoescht to identify the nuclei and with fluorescent labeled Ab against the surface molecules CD86 (M1) and CD206 (M2a, M2c). Fluorescence was analyzed with the software for static cytometry ScanR (>5000 cells/well). Hoescht fluorescence was used to record the spatial disposition of cells, distinguishing between isolated and aggregated/multinucleated cells. The analysis of the fluorescence emitted by the surface markers allowed us to discriminate between independent cells in close proximity and multinucleated cells. All activation treatments induced a slight reduction in the number of cells per area (LPS+IFNγ: 93±3, IL4: 90±2, IL10: 97±3 % of control values) which was not modified by cotreatment with progastrin (10-7M; 90±4%, 90±2% and 87±7% respectively). The cytometric analysis detected the presence of spontaneously generated multinucleated formations including 3-10 nuclei (mean: 3.4±0.2). IL4 significantly increased the number of these formations (142± 6 %, p<0.05 vs control values). IL10 did not induce any significant change (94±8%) while LPS+IFNγ significantly reduced its presence (70±7%, p<0.05 vs control values). Co-treatment with progastrin significantly reduced macrophage fusion in all cases (see figure). None of these treatments induced a significant effect in the mean size of these multinucleated forms. Our results indicate that progastrin inhibits macrophage fusion. This effect takes place independently of the pattern of macrophage activation. We hypothesized that, if this inhibitory effect of progastrin is also effective against macrophage fusion with cancer cells, the peptide may constitute a neutralizing force against metastasis.
Mo1109 Immune Regulation of the Intestinal Progenitor Cell Microenvironment Tim Vanuytsel, Luigi Notari, Shu Yan, Aiping Zhao, Jennifer A. Bohl, Leon McLean, Rex Sun, Joseph F. Urban, Allen Smith, Jan F. Tack, Terez Shea-Donohue Background: The gastrointestinal tract is the largest interface between the external and internal milieux. To adapt to different environmental challenges, the epithelium renews every 5 to 7 days. Enteric infections induce a proliferative response in the colon; however, knowledge of how different cytokine profiles in the stem-cell microenvironment influence progenitor cell proliferation and migration is limited. Aim: To elucidate the effect of different cytokine microenvironments on intestinal progenitor cells. Materials and methods: C57BL/ 6 mice (N=25) were infected with Citrobacter rodentium (Cr), a model for enterotoxigenic E. coli, by oral gavage of 1010 CFU and studied every week (n=5/group) for 4 weeks post infection (PI). BALB/c and STAT6 knockout (KO) (N=20/group) were infected with the cecal-dwelling Trichuris muris, a model for human whipworm, by gavage of 200 embryonated eggs and studied every week (n=5/group) for 4 weeks. All mice were injected with 10mg bromodeoxyuridine (BrdU) 2 hours before sacrifice. Colonic segments were processed for histology and gene expression. BrdU positive cells per crypt were counted and the mucosal height measured in >10 well-oriented crypts/mouse. Gene expression of IFNγ (Th1), IL17A (Th17), IL4 and IL13 (Th2) and CXCL10 was quantified by real-time PCR. Results: Cr upregulated IFNγ and IL17A, cytokines needed for Cr clearance by day 14 PI (Table 1) coinciding with a proliferative response of the colonic epithelium indicated by an increase in the number of BrdU positive cells per crypt (13.9±1.6 vs. 5.2±0.7; p<0.01) and in mucosal height (191±6 vs. 119±6 μm; p<0.01). In WT T. muris infected mice , the maximal increase of IL4 and IL13, cytokines needed for clearance, occured at day 14 PI and coincided with a modest upregulation of IFNγ and CXCL10 (Table 1). At this time there was also a transient increase in BrdU positive cells per crypt (11±0.6 vs. 4.9±0.3; p<0.01) and mucosal height (131±10 vs. 97±2 μm; p<0.01) preceding clearance. In contrast, day 14 PI STAT6 KO mice lacked upregulation of Th2 or Th1 cytokines or increased epithelial proliferation despite the presence of worms. These mice develop a chronic infection with a proliferative response at day 28 PI that also coincides with the generation of a Th1 predominant response (Table 1) and CXCL10 upregulation. Conclusion: By manipulating the colon cytokine microenvironment with two polarized infections in different backgrounds, we showed that the maximal proliferative response coincides with the mounting of a Th1 cytokine response and production of CXCL10. The latter is upregulated in IBD-patients and is a well-known inhibitor of epithelial cell migration which leads to crypt hyperplasia in the presence of proliferation (Cliffe et al. 2005). Our findings provide further insight in the immuneregulation of the progenitor cell microenvironment of the colon.
Effect of progastrin on macrophage fusion. * p<0.05 vs corresponding control group (RMANOVA + Newman-Keuls test). Mo1108
Changes in gene-expression of cytokines during enteric infections. Data expressed as average fold-change±SEM. #p<0.05; *p<0.01
Gastric Sonic Hedgehog Acts as a Macrophage Chemoattractant During the Development of the Immune Response to Helicobacter pylori Infection Michael A. Schumacher, Jessica M. Donnelly, Amy C. Engevik, Chang Xiao, Li Yang, Susan H. Kenny, Andrea Varro, Frederic Hollande, Linda C. Samuelson, Yana Zavros Background: Macrophages are essential innate responders to Helicobacter pylori (H. pylori)derived signals from the epithelium that are crucial to the development of gastritis. Sonic Hedgehog (Shh), a regulator of gastric epithelial differentiation and function, is known to regulate the host gastric immune response, but the precise nature of its role is unknown. Hypothesis: Gastric Shh acts as a macrophage chemoattractant during the innate immune
S-597
AGA Abstracts
AGA Abstracts
In addition, TNFα protein release in the conditioned media was measured with an enzymelinked immunosorbent assay (ELISA). KB-R7785(10μM) was used to inhibit ADAMs' activities. RNA interference was performed to knock down endogenous ADAM 17 and AREGregulating protein(ARP) 36. The association of ARP36 with ADAM17 was analyzed with IP with anti-ARP36 antibody followed by western blotting(WB) with anti-ADAM17 antibody. Results: The membrane protein immunoprecipitated with anti-proAREG antibody was identified as ARP36 with MALDI/TOFMS analysis. ELISA and AP assay showed IL-1β-induced TNFα shedding in HCT116 and HT29 cells and that TPA did TNFα shedding in U937 cells within 5 hrs. KB-R7785 and depletion of ADAM17 significantly blocked TNFα shedding with IL-1β and TPA. Depletion of ARP36 significantly inhibited TNFα shedding with IL1β and TPA in ELISA and AP assay. On the other hand knockdown of ARP36 did not abrogate the shedding of AREG and HB-EGF for which ADAM17 is responsible. IP and WB showed the association of ARP36 with ADAM17. Conclusions: ADAM17 is closely associated with APR36. ADAM17 is involved in IL-1β-induced TNFα shedding in colon epithelial cells and TPA-induced TNFα shedding in monocytes. ARP36 plays an important role on TNF shedding with IL-1β and TPA. Inhibition of ARP36 may be a new therapeutic strategy for prevention of TNFα shedding during IBD inflammation.