Mouse Model Of Pancreatitis Research Articles

Anterior Gradient 2 (AGR2) Induced Epidermal Growth Factor Receptor (EGFR) Signaling Is Essential for Murine Pancreatitis-Associated Tissue Regeneration.

A recently published study identified Anterior Gradient 2 (AGR2) as a regulator of EGFR signaling by promoting receptor presentation from the endoplasmic reticulum to the cell surface. AGR2 also promotes tissue regeneration in amphibians and fish. Whether AGR2-induced EGFR signaling is essential for tissue regeneration in higher vertebrates was evaluated using a well-characterized murine model for pancreatitis. The impact of AGR2 expression and EGFR signaling on tissue regeneration was evaluated using the caerulein-induced pancreatitis mouse model. EGFR signaling and cell proliferation were examined in the context of the AGR2-/- null mouse or with the EGFR-specific tyrosine kinase inhibitor, AG1478. In addition, the Hippo signaling coactivator YAP1 was evaluated in the context of AGR2 expression during pancreatitis. Pancreatitis-induced AGR2 expression enabled EGFR translocation to the plasma membrane, the initiation of cell signaling, and cell proliferation. EGFR signaling and tissue regeneration were partially inhibited by the tyrosine kinase inhibitor AG1478, but absent in the AGR2-/- null mouse. AG1478-treated and AGR2-/- null mice with pancreatitis died whereas all wild-type controls recovered. YAP1 activation was also dependent on pancreatitis-induced AGR2 expression. AGR2-induced EGFR signaling was essential for tissue regeneration and recovery from pancreatitis. The results establish tissue regeneration as a major function of AGR2-induced EGFR signaling in adult higher vertebrates. Enhanced AGR2 expression and EGFR signaling are also universally present in human pancreatic cancer, which support a linkage between tissue injury, regeneration, and cancer pathogenesis.

Aryl Hydrocarbon Receptor Ligands in Cigarette Smoke Induce Production of Interleukin-22 to Promote Pancreatic Fibrosis in Models of Chronic Pancreatitis

Cigarette smoke has been identified as an independent risk factor for chronic pancreatitis (CP). Little is known about the mechanisms by which smoking promotes development of CP. We assessed the effects of aryl hydrocarbon receptor (AhR) ligands found in cigarette smoke on immune cell activation in humans and pancreatic fibrosis in animal models ofCP. We obtained serum samples from patients with CP treated at Stanford University hospital and healthy individuals (controls) and isolated CD4+ T cells. Levels ofinterleukin-22 (IL22) were measured by enzyme-linked immunosorbent assay and smoking histories were collected. Tcells from healthy nonsmokers and smokers were stimulatedand incubated with AhR agonists (2,3,7,8-tetrachlorodibenzo-p-dioxin or benzo[a]pyrene) or antagonists and analyzed by flow cytometry. Mice were given intraperitoneal injections of caerulein or saline, with or without lipopolysaccharide, to induce CP. Some mice were given intraperitoneal injections of AhR agonists at the start of caerulein injection, with or without an antibody against IL22 (anti-IL22) starting 2 weeks after the first caerulein injection, or recombinant mouse IL22 or vehicle (control) intraperitoneally 4 weeks after the first caerulein injection. Mice were exposed to normal air or cigarette smoke for 6 h/d for 7 weeks and expression of AhR gene targets was measured. Pancreata were collected from all mice and analyzed by histology and quantitative reverse transcription polymerase chain reaction. Pancreatic stellate cells and T cells were isolated and studied using immunoblot, immunofluorescence, flow cytometry, and enzyme-linked immunosorbent analyses. Mice given AhR agonists developed more severe pancreatic fibrosis (based on decreased pancreas size, histology, and increased expression of fibrosis-associated genes) than mice not given agonists after caerulein injection. In mice given saline instead of caerulein, AhR ligands did not induce fibrosis. Pancreatic T cells from mice given AhR agonists and caerulein were activated and expressed IL22, but not IL17 or interferon gamma. Human T cells exposed to AhR agonists up-regulated expression of IL22. In mice given anti-IL22, pancreatic fibrosis did not progress, whereas mice given recombinant IL22 had a smaller pancreas and increased fibrosis. Pancreatic stellate cells isolated from mouse and human pancreata expressed the IL22 receptor IL22RA1. Incubation of the pancreatic stellate cells with IL22 induced their expression of the extracellular matrix genes fibronectin 1 and collagen type I α1 chain, but not α2 smooth muscle actin or transforming growth factor-β. Serum samples from smokers had significantly higher levels of IL22 than those from nonsmokers. AhR ligands found in cigarette smoke increase the severity of pancreatic fibrosis in mouse models of pancreatitis via up-regulation of IL22. This pathway might be targeted for treatment of CP and serve as a biomarker of disease.

Dynamic landscape of pancreatic carcinogenesis reveals early molecular networks of malignancy

ObjectiveThe initial steps of pancreatic regeneration versus carcinogenesis are insufficiently understood. Although a combination of oncogenic Kras and inflammation has been shown to induce malignancy, molecular networks of early carcinogenesis...

Abstract 1452: IL-15 overexpression protects cerulein-induced fibrosis in the mouse model of chronic pancreatitis

Abstract Introduction: Earlier, interleukin (IL)-6, IL-8, IL-1β and IL-10 are implicated in the pathogenesis of pancreatitis. Recently, we observed reduced level of IL-15 in cerulein- induced acute and chronic mouse model of pancreatitis. IL-15 is a pleiotropic cytokine that has an important role in innate immunity. Therefore, we tested the hypothesis that IL-15 overexpression improves the pathogenesis of cerulein-induced pancreatitis. Experimental procedure: Accordingly, we tested our hypothesis by inducing chronic pancreatitis in rIL-15 pretreated Balb/c mice. Cerulein was given by repetitive intraperitoneal (i.p.) injections as reported earlier (50 μg/kg, 6 hourly injections/day, 3 days/week) along with the rIL-15 (5 μg in 100μl saline/ two-times/week/mice) for up to 4 weeks; the control mice received 100μl saline or saline with 5 μg IL-15. Mice were sacrificed 3 days after the last cerulein injection. Histopathological evaluation of H&E stained tissue sections was performed including tissue remodeling and the accumulation of collagen by Masson's trichrome stain in the tissue sections. Additionally, pro-inflammatory and pro-fibrotic gene i.e. TGF-β1, IL-6, IL-8, Collagen 1 and α-SMA levels were measured by ELISA, immunofluorescence, qPCR and immunoblot analysis. Summary: We report acinar cells atrophy, induced inflammatiory cells and cytokines in the pancreas of cerulein treated mice along with perivascular collagen deposition compare to saline treated mice. Interestingly, rIL-15 treated and cerulein given mice showed significantly improved morphology of acinar cells and reduced perivascular collagen. Further, we also report that protein levels of TGF-β1 and α-SMA is also reduced in the pancreas of cerulein injected and IL-15 treated mice compare to cerulein treated mice by performing western blot and immunohistochemistry. Conclusion: Our data show that IL-15 overexpression protects mice from cerulein-induced pancreatic pathogenesis including fibrosis. Taken together, rIL-15 therapy may be a novel strategy to treat pancreatic fibrosis, and may also helpful to treat pancreatic cancer patients by down-regulating tissue fibrogenesis. Funding: NIH R01 DK067255 (AM), NIH R01 AI080581 (AM), Citation Format: MURLI MANOHAR, SATHISHA UPPARAHALLI VENKATESHAIAH, CHANDRASHEKARA PUTANAPURA MAHADEVAPPA, ALOK KUMAR VERMA, ANIL MISHRA. IL-15 overexpression protects cerulein-induced fibrosis in the mouse model of chronic pancreatitis. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1452.

Nonoverlapping roles of PD-1 and FoxP3 in maintaining immune tolerance in a novel autoimmune pancreatitis mouse model

PD-1 (programmed-death 1), an immune-inhibitory receptor required for immune self-tolerance whose deficiency causes autoimmunity with variable severity and tissue specificity depending on other genetic factors, is expressed on activated T cells, including the transcription factor FoxP3(+) Treg cells known to play critical roles in maintaining immune tolerance. However, whether PD-1 expression by the Treg cells is required for their immune regulatory function, especially in autoimmune settings, is still unclear. We found that mice with partial FoxP3 insufficiency developed early-onset lympho-proliferation and lethal autoimmune pancreatitis only when PD-1 is absent. The autoimmune phenotype was rescued by the transfer of FoxP3-sufficient T cells, regardless of whether they were derived from WT or PD-1-deficient mice, indicating that Treg cells dominantly protect against development of spontaneous autoimmunity without intrinsic expression of PD-1. The absence of PD-1 combined with partial FoxP3 insufficiency, however, led to generation of ex-FoxP3 T cells with proinflammatory properties and expansion of effector/memory T cells that contributed to the autoimmune destruction of target tissues. Altogether, the results suggest that PD-1 and FoxP3 work collaboratively in maintaining immune tolerance mostly through nonoverlapping pathways. Thus, PD-1 is modulating the activation threshold and maintaining the balance between regulatory and effector T cells, whereas FoxP3 is sufficient for dominant regulation through maintaining the integrity of the Treg function. We suggest that genetic or environmental factors that even moderately affect the expression of both PD-1 and FoxP3 can cause life-threatening autoimmune diseases by disrupting the T-cell homeostasis.

Autophagy Inhibition Dysregulates TBK1 Signaling and Promotes Pancreatic Inflammation.

Autophagy promotes tumor progression downstream of oncogenic KRAS, yet also restrains inflammation and dysplasia through mechanisms that remain incompletely characterized. Understanding the basis of this paradox has important implications for the optimal targeting of autophagy in cancer. Using a mouse model of cerulein-induced pancreatitis, we found that loss of autophagy by deletion of Atg5 enhanced activation of the IκB kinase (IKK)-related kinase TBK1 in vivo, associated with increased neutrophil and T-cell infiltration and PD-L1 upregulation. Consistent with this observation, pharmacologic or genetic inhibition of autophagy in pancreatic ductal adenocarcinoma cells, including suppression of the autophagy receptors NDP52 or p62, prolonged TBK1 activation and increased expression of CCL5, IL6, and several other T-cell and neutrophil chemotactic cytokines in vitro Defective autophagy also promoted PD-L1 upregulation, which is particularly pronounced downstream of IFNγ signaling and involves JAK pathway activation. Treatment with the TBK1/IKKε/JAK inhibitor CYT387 (also known as momelotinib) not only inhibits autophagy, but also suppresses this feedback inflammation and reduces PD-L1 expression, limiting KRAS-driven pancreatic dysplasia. These findings could contribute to the dual role of autophagy in oncogenesis and have important consequences for its therapeutic targeting. Cancer Immunol Res; 4(6); 520-30. ©2016 AACR.

The roles and mechanisms of p-STAT3 signaling pathway in acute pancreatitis

To detect the expression ofsignal transducer and activator of transcription 3 (STAT3) in pancreatic tissue of the mouse model of pancreatitis, and to explore its role in the evolution of acute pancreatitis. Forty-eight healthy male balb/c mice were randomly divided into 3 groups (n=16):control group (Con) 0.09% NaCl, intraperitoneal injection; mild acute pancreatitis group (MAP) caerulein, intraperitoneal injection; severe acute pancreatitis group (SAP) caerulein plus lipopolysaccharide(LPS), intraperitoneal injection. The mice were sacrificed after 2 h and 6 h after intraperitoneall injection. Serum was isolated for amylase activity. Pancreatic was isolated and weighedto calculate the pancreatic wet weight ratio. Myeloperoxidase (MPO) activity was measured to assess the degree of inflammatory cell infiltration in lung tissue. Using HE staining, the pathological changes of pancreatic and lung were observed under the light microscope. The expression of phosphorylated STAT3 (p-STAT3) was detected by Western blot. Compared with control group, serum amylase activity, pancreatic wet weight ratio and lung MPO activity were significantlyincreased (P<0.05) in MAP and SAP group at each time point, especially SAP group showed higher levels of MPO activity than that in MAP group (P<0.01). The pathological changes of pancreas and lung were observed after modeling in 2 h. Western blot showed the expression of p-STAT3 could be detected in SAP group, the level increased most significantly after modeling 2 h, and decreased slightly after 6 h. The level of p-STAT3 was low in MAP group and negative in Con group at each time point. The expression of p-STAT3 in MAP and SAP groups are significantly different from that in control group, which indicates that STAT3 isclosely related in acute pancreatitis. Inhibition of STAT3 activity is a potential target to alleviate acute pancreatitis progression.

A proinflammatary role of Mlkl dependent necroptosis in pancreatitis

Rip3 was reported to play a pivotal role in various pathophysiological conditions, such as Crohn's disease, hepatitis, atherosclerosis and systemic inflammatory response syndrome. To determine whether Mlkl also plays a role in the progression of necroptosis‐associated diseases, we generated Mlkl knockout mice by gene disruption. Homozygous Mlkl‐deficient (Mlkl−/−) mice are viable, healthy, fertile, born with normal Mendelian frequency and do not display any gross physical or behavioral abnormalities. The expression pattern of Mlkl is quite different from that of Rip3. The expression level of Mlkl protein is high in thymus, colon, intestine, liver, spleen and lung, much lower in skeletal muscle, heart and kidney, and undetectable in the brain. We analyzed wild‐type and Mlkl−/− mice in an acute pancreatitis mouse model induced by cerulein stimulation. Wild‐type mice injected with cerulein every hour for 6 consecutive hours showed much more severe acinar cell necrosis than Mlkl−/− littermates under the same treatment; phosphorylation of Mlkl was detected in wild‐type but not Mlkl−/− acinar cells, and many more inflammatory cells, such as macrophages, neutrophils and other granulocytes, were found in wild‐type compared to Mlkl−/− pancreas and blood. The mRNA expression levels of 5 inflammatory cytokines, including IL‐6 and KC, were decreased significantly in the pancreas of mice lacking Mlkl. Our findings indicate that necroptosis plays a strong proinflammatory role in pancreatitis.

An optimised mouse model of chronic pancreatitis with a combination of ethanol and cerulein.

IntroductionChronic pancreatitis (CP) is an intractable and multi-factorial disorder. Developing appropriate animal models is an essential step in pancreatitis research, and the best ones are those which mimic the human disorder both aetiologically and pathophysiologically. The current study presents an optimised protocol for creating a murine model of CP, which mimics the initial steps of chronic pancreatitis in alcohol chronic pancreatitis and compares it with two other mouse models treated with cerulein or ethanol alone.Material and methodsThirty-two male C57BL/6 mice were randomly selected, divided into four groups, and treated intraperitoneally with saline (10 ml/kg, control group), ethanol (3 g/kg; 30% v/v), cerulein (50 µg/kg), or ethanol + cerulein, for six weeks. Histopathological and immunohistochemical assays for chronic pancreatitis index along with real-time PCR assessments for mRNA levels of inflammatory cytokines and fibrogenic markers were conducted to verify the CP induction.ResultsThe results indicated that CP index (CPI) was significantly increased in ethanol-cerulein mice compared to the saline, ethanol, and cerulein groups (p < 0.001). Interleukin 1β (IL-1β), tumor necrosis factor α (TNF-α), transforming growth factor β (TGF-β), α-smooth muscle actin (α-SMA), and myeloperoxidase activity were also significantly greater in both cerulein and ethanol-cerulein groups than in the saline treated animals (p < 0.001). Immunohistochemical analysis revealed enhanced expression of TGF-β and α-SMA in ethanol-cerulein mice compared to the saline group.ConclusionsIntraperitoneal (IP) injections of ethanol and cerulein could successfully induce CP in mice. IP injections of ethanol provide higher reproducibility compared to ethanol feeding. The model is simple, non-invasive, reproducible, and time-saving. Since the protocol mimics the initial phases of CP development in alcoholics, it can be used for investigating basic mechanisms and testing new therapies.

Design, Synthesis, and Biological Evaluation of 1-Benzyl-1H-pyrazole Derivatives as Receptor Interacting Protein 1 Kinase Inhibitors.

Receptor interacting protein 1 (RIP1) kinase plays an important role in necroptosis, and inhibitors of the RIP1 kinase are thought to have a potential therapeutic value in the treatment of diseases related to necrosis. Herein, we report the structural optimization of a RIP1 kinase inhibitor, 1-(2,4-dichlorobenzyl)-3-nitro-1H-pyrazole (1a). A number of 1-benzyl-1H-pyrazole derivatives were synthesized and structure-activity relationship (SAR) analysis led to the discovery of a potent compound, 4b, which showed a Kd value of 0.078 μm against the RIP1 kinase and an EC50 value of 0.160 μm in a cell necroptosis inhibitory assay. Compound 4b also displayed considerable ability to protect the pancreas in an l-arginine-induced pancreatitis mouse model.

Inactivation of TGFβ receptor II signalling in pancreatic epithelial cells promotes acinar cell proliferation, acinar-to-ductal metaplasia and fibrosis during pancreatitis.

Determining signalling pathways that regulate pancreatic regeneration following pancreatitis is critical for implementing therapeutic interventions. In this study we elucidated the molecular mechanisms underlying the effects of transforming growth factor-β (TGFβ) in pancreatic epithelial cells during tissue regeneration. To this end, we conditionally inactivated TGFβ receptor II (TGFβ-RII) using a Cre-LoxP system under the control of pancreas transcription factor 1a (PTF1a) promoter, specific for the pancreatic epithelium, and evaluated the molecular and cellular changes in a mouse model of cerulein-induced pancreatitis. We show that TGFβ-RII signalling does not mediate the initial acinar cell damage observed at the onset of pancreatitis. However, TGFβ-RII signalling not only restricts acinar cell replication during the regenerative phase of the disease but also limits ADM formation in vivo and in vitro in a cell-autonomous manner. Analyses of molecular mechanisms underlying the observed phenotype revealed that TGFβ-RII signalling stimulates the expression of cyclin-dependent kinase inhibitors and intersects with the EGFR signalling axis. Finally, TGFβ-RII ablation in epithelial cells resulted in increased infiltration of inflammatory cells in the early phases of pancreatitis and increased activation of pancreatic stellate cells in the later stages of pancreatitis, thus highlighting a TGFβ-based crosstalk between epithelial and stromal cells regulating the development of pancreatic inflammation and fibrosis. Collectively, our data not only contribute to clarifying the cellular processes governing pancreatic tissue regeneration, but also emphasize the conserved role of TGFβ as a tumour suppressor, both in the regenerative process following pancreatitis and in the initial phases of pancreatic cancer.

Ablation of NEMO/ IKKgamma Exacerbates Fibrosis and Impairs Regeneration in a mouse model of pancreatitis

Ablation of NEMO/ IKKgamma Exacerbates Fibrosis and Impairs Regeneration in a mouse model of pancreatitis

Changes in the Expression of Glucose-regulated Protein 78 in the Occurrence and Progression of Pancreatic Cancer in Mouse Models.

To investigate the changes in the expression of glucose-regulated protein 78 (GRP78) in the occurrence and progression of pancreatic cancer in mouse models. The mouse models of chronic pancreatitis,pancreatic intraepithelial neoplasia (PanIN), and pancreatic cancer were successfully established by dimethyl benzene and anthracene (DMBA) embedding in situ. GRP78 expression was detected in various stages by immunohistochemistry. Of these 60 mouse models, 18 mice (30%) died during the observation period. Two months after the embedding,the survived mice were sacrificed,and HE staining and IHC staining were performed. Among these mice, 9 (15%) developed chronic pancreatitis; 18 (30%) had PanIN [PanIN1,5 (8.3%);P anIN2,9 (15%); and PanIN 3,4 (6.7%)];15 (25%) developed pancreatic cancer. Immunohistochemistry showed that the expression of GRP78 in pancreatic cancer tissue was significantly higher than that in adjacent noncancerous duct cells (χ(2)=13.39,P =0.000). Also, GRP78 expression in pancreatic cancer tissue and high grade PanIN was significantly higher than that in low grade PanIN and chronic pancreatitis (χ(2)=17.84,P=0.000). The expression of GRP78 remarkably differs in different stages of pancreatic cancer and therefore is associated with the occurrence and progression of this disease.

Pancreatic duct glands (PDGs) are a progenitor compartment responsible for pancreatic ductal epithelial repair

Pancreatic duct glands (PDGs) have molecular features known to mark stem cell niches, but their function remains to be determined. To investigate the role of PDGs as a progenitor niche, PDGs were analyzed in both humans and mice. Cells were characterized by immunohistochemistry and microarray analysis. In vivo proliferative activity and migration of PDG cells were evaluated using a BrdU tag-and-chase strategy in a mouse model of pancreatitis. In vitro migration assays were used to determine the role of trefoil factor (TFF) -1 and 2 in cell migration. Proliferative activity in the pancreatic epithelium in response to inflammatory injury is identified principally within the PDG compartment. These proliferating cells then migrate out of the PDG compartment to populate the pancreatic duct. Most of the pancreatic epithelial migration occurs within 5days and relies, in part, on TFF-1 and -2. After migration, PDG cells lose their PDG-specific markers and gain a more mature pancreatic ductal phenotype. Expression analysis of the PDG epithelium reveals enrichment of embryonic and stem cell pathways. These results suggest that PDGs are an epithelial progenitor compartment that gives rise to mature differentiated progeny that migrate to the pancreatic duct. Thus PDGs are a progenitor niche important for pancreatic epithelial regeneration.

Complement Component 5 Mediates Development of Fibrosis, via Activation of Stellate Cells, in 2 Mouse Models of Chronic Pancreatitis

Background & AimsLittle is known about the pathogenic mechanisms of chronic pancreatitis. We investigated the roles of complement component 5 (C5) in pancreatic fibrogenesis in mice and patients.MethodsChronic pancreatitis was induced by ligation of the midpancreatic duct, followed by a single supramaximal intraperitoneal injection of cerulein, in C57Bl6 (control) and C5-deficient mice. Some mice were given injections of 2 different antagonists of the receptor for C5a over 21 days. In a separate model, mice were given injections of cerulein for 10 weeks to induce chronic pancreatitis. Direct effects of C5 were studied in cultured primary cells. We performed genotype analysis for the single-nucleotide polymorphisms rs 17611 and rs 2300929 in C5 in patients with pancreatitis and healthy individuals (controls). Blood cells from 976 subjects were analyzed by transcriptional profiling.ResultsDuring the initial phase of pancreatitis, levels of pancreatic damage were similar between C5-deficient and control mice. During later stages of pancreatitis, C5-deficient mice and mice given injections of C5a-receptor antagonists developed significantly less pancreatic fibrosis than control mice. Primary pancreatic stellate cells were activated in vitro by C5a. There were no differences in the rs 2300929 SNP between subjects with or without pancreatitis, but the minor allele rs17611 was associated with a significant increase in levels of C5 in whole blood.ConclusionsIn mice, loss of C5 or injection of a C5a-receptor antagonist significantly reduced the level of fibrosis of chronic pancreatitis, but this was not a consequence of milder disease in early stages of pancreatitis. C5 might be a therapeutic target for chronic pancreatitis.

Exposure to Radiocontrast Agents Induces Pancreatic Inflammation by Activation of Nuclear Factor-κB, Calcium Signaling, and Calcineurin

Radiocontrast agents are required for radiographic procedures, but these agents can injure tissues by unknown mechanisms. We investigated whether exposure of pancreatic tissues to radiocontrast agents during endoscopic retrograde cholangiopancreatography (ERCP) causes pancreatic inflammation, and studied the effects of these agents on human cell lines and in mice. We exposed mouse and human acinar cells to the radiocontrast agent iohexol (Omnipaque; GE Healthcare, Princeton, NJ) and measured intracellular release of Ca(2+), calcineurin activation (using a luciferase reporter), activation of nuclear factor-κB (NF-κB, using a luciferase reporter), and cell necrosis (via propidium iodide uptake). We infused the radiocontrast agent into the pancreatic ducts of wild-type mice (C57BL/6) to create a mouse model of post-ERCP pancreatitis; some mice were given intraperitoneal injections of the calcineurin inhibitor FK506 before and after infusion of the radiocontrast agent. CnAβ(-/-) mice also were used. This experiment also was performed in mice given infusions of adeno-associated virus 6-NF-κB-luciferase, to assess activation of this transcription factor in vivo. Incubation of mouse and human acinar cells, but not HEK293 or COS7 cells, with iohexol led to a peak and then plateau in Ca(2+) signaling, along with activation of the transcription factors NF-κB and nuclear factor of activated T cells. Suppressing Ca(2+) signaling or calcineurin with BAPTA, cyclosporine A, or FK506 prevented activation of NF-κB and acinar cell injury. Calcineurin Aβ-deficient mice were protected against induction of pancreatic inflammation by iohexol. The calcineurin inhibitor FK506 prevented contrast-induced activation of NF-κB in pancreata of mice, this was observed by live imaging of mice given infusions of adeno-associated virus 6-NF-κB-luciferase. Radiocontrast agents cause pancreatic inflammation in mice, via activation of NF-κB, Ca(2+) signaling, and calcineurin. Calcineurin inhibitors might be developed to prevent post-ERCP pancreatitis in patients.

757 Pharmacologic Inhibition of RGD-Binding Integrins Attenuates Pancreatic Fibrogenesis in a Mouse Model of Chronic Pancreatitis

757 Pharmacologic Inhibition of RGD-Binding Integrins Attenuates Pancreatic Fibrogenesis in a Mouse Model of Chronic Pancreatitis

Granulocyte colony-stimulating factor reduces fibrosis in a mouse model of chronic pancreatitis.

BackgroundChronic pancreatitis (CP) is a necroinflammatory process resulting in extensive pancreatic fibrosis. Granulocyte colony-stimulating factor (G-CSF), a hematopoietic stem cell mobilizer, has been shown to exert an anti-fibrotic effect partly through the enrichment of bone marrow (BM) cells in fibrotic organ. We aimed to test the effect of G-CSF on fibrosis in a mouse model of CP.MethodsCP was induced in C57Bl/6J mice by consecutive cerulein injection (50 µg/kg/day, 2 days a week) for 6 weeks. Mice were then treated with G-CSF (200 µg/kg/day, 5 day a week) or normal saline for 1 week, and sacrificed at week 7 or week 9 after first cerulein injection. Pancreatic histology, pancreatic matrix metallopeptidase 9 (MMP-9), MMP-13 and collagen expression were examined. Pancreatic myofibroblasts were isolated and cultured with G-CSF. Collagen, MMP-9 and MMP-13 expression by myofibroblasts was examined. The BM-mismatched mice model was used to examine the change of BM-derived myofibroblasts and non-myofibroblastic BM cells by G-CSF in the pancreas.ResultsThe pancreatic collagen expression were significantly decreased in the G-CSF-treated group sacrificed at week 9. While collagen produced from myofibroblasts was not affected by G-CSF, the increase of MMP13 expression was observed in vitro. There were no effect of G-CSF in the number of myofibroblasts and BM-derived myofibroblasts. However, the number of non-myofibroblastic BM cells and macrophages were significantly increased in the pancreata of cerulein- and G-CSF-treated mice, suggesting a potential anti-fibrotic role of non-myofibroblastic BM cells and macrophages stimulated by G-CSF.ConclusionsOur data indicated that G-CSF contributed to the regression of pancreatic fibrosis. The anti-fibrotic effects were possibly through the stimulation of MMP-13 from myofibroblasts, and the enhanced accumulation of non-myofibroblastic BM cells and macrophages in the pancreas.

Protective effects and mechanisms of G5 PAMAM dendrimers against acute pancreatitis induced by caerulein in mice.

In this study, generation 5 (G5) polyamidoamine (PAMAM) dendrimers with two different surface groups, G4.5-COOH and G5-OH, were investigated for their protective effects on pancreas injury in a caerulein-induced acute pancreatitis (AP) mouse model. Both dendrimers significantly decreased pathological changes in the pancreas and reduced the inflammatory infiltration of macrophages in pancreatic tissues. In addition, the expression of pro-inflammatory cytokines was significantly inhibited by the two dendrimers, not only in pancreatic tissues from AP mice but also in vitro in mouse peritoneal macrophages with LPS-induced inflammation. G4.5-COOH, which had better in vivo protective effects for AP than G5-OH, led to a significant reduction in the total number of plasma white blood cells (WBCs) and monocytes in AP mice, and its anti-inflammatory mechanism was related to inhibition of the nuclear translocation of NF-κB in macrophages.

Highlights from Recent Cancer Literature

Highlights from Recent Cancer Literature