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Tang G, Yu C, Xiang K, Gao M, Liu Z, Yang B, Yang M, Zhao S. Inhibition of ANXA2 regulated by SRF attenuates the development of severe acute pancreatitis by inhibiting the NF-κB signaling pathway. Inflamm Res 2022; 71:1067-1078. [PMID: 35900381 DOI: 10.1007/s00011-022-01609-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 05/31/2022] [Accepted: 07/04/2022] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND Acute pancreatitis (AP) is an inflammatory process of the pancreas resulting from biliary obstruction or alcohol consumption. Approximately, 10-20% of AP can evolve into severe AP (SAP). In this study, we sought to explore the physiological roles of the transcription factor serum response factor (SRF), annexin A2 (ANXA2), and nuclear factor-kappaB (NF-κB) in SAP. METHODS C57BL/6 mice and rat pancreatic acinar cells (AR42J) were used to establish an AP model in vivo and in vitro by cerulein with or without lipopolysaccharide (LPS). Production of pro-inflammatory cytokines (IL-1β and TNF-α) were examined by ELISA and immunoblotting analysis. Hematoxylin and eosin (HE) staining and TUNEL staining were performed to evaluate pathological changes in the course of AP. Apoptosis was examined by flow cytometric and immunoblotting analysis. Molecular interactions were tested by dual luciferase reporter, ChIP, and Co-IP assays. RESULTS ANXA2 was overexpressed in AP and correlated to the severity of AP. ANXA2 knockdown rescued pancreatic acinar cells against inflammation and apoptosis induced by cerulein with or without LPS. Mechanistic investigations revealed that SRF bound with the ANXA2 promoter region and repressed its expression. ANXA2 could activate the NF-κB signaling pathway by inducing the nuclear translocation of p50. SRF-mediated transcriptional repression of ANXA2-protected pancreatic acinar cells against AP-like injury through repressing the NF-κB signaling pathway. CONCLUSION Our study highlighted a regulatory network consisting of SRF, ANXA2, and NF-κB that was involved in AP progression, possibly providing some novel targets for treating SAP.
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Affiliation(s)
- Guanxiu Tang
- The Department of Gerontology, The Third Xiangya Hospital of Central South University, No. 138, Tongzipo Road, Yuelu District, Changsha, 410013, Hunan Province, People's Republic of China
| | - Can Yu
- The Department of Intensive Care Unit (ICU), The Third Xiangya Hospital of Central South University, No. 138, Tongzipo Road, Yuelu District, Changsha, 410013, Hunan Province, People's Republic of China
| | - Kaimin Xiang
- The Department of Gastrointestinal Surgery, The Third Xiangya Hospital of Central South University, No. 138, Tongzipo Road, Yuelu District, Changsha, 410013, Hunan Province, People's Republic of China
| | - Min Gao
- The Department of Intensive Care Unit (ICU), The Third Xiangya Hospital of Central South University, No. 138, Tongzipo Road, Yuelu District, Changsha, 410013, Hunan Province, People's Republic of China
| | - Zuoliang Liu
- The Department of Intensive Care Unit (ICU), The Third Xiangya Hospital of Central South University, No. 138, Tongzipo Road, Yuelu District, Changsha, 410013, Hunan Province, People's Republic of China
| | - Bingchang Yang
- The Department of Intensive Care Unit (ICU), The Third Xiangya Hospital of Central South University, No. 138, Tongzipo Road, Yuelu District, Changsha, 410013, Hunan Province, People's Republic of China
| | - Mingshi Yang
- The Department of Intensive Care Unit (ICU), The Third Xiangya Hospital of Central South University, No. 138, Tongzipo Road, Yuelu District, Changsha, 410013, Hunan Province, People's Republic of China
| | - Shangping Zhao
- The Department of Intensive Care Unit (ICU), The Third Xiangya Hospital of Central South University, No. 138, Tongzipo Road, Yuelu District, Changsha, 410013, Hunan Province, People's Republic of China.
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Saloman JL, Albers KM, Cruz-Monserrate Z, Davis BM, Edderkaoui M, Eibl G, Epouhe AY, Gedeon JY, Gorelick FS, Grippo PJ, Groblewski GE, Husain SZ, Lai KK, Pandol SJ, Uc A, Wen L, Whitcomb DC. Animal Models: Challenges and Opportunities to Determine Optimal Experimental Models of Pancreatitis and Pancreatic Cancer. Pancreas 2019; 48:759-779. [PMID: 31206467 PMCID: PMC6581211 DOI: 10.1097/mpa.0000000000001335] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
At the 2018 PancreasFest meeting, experts participating in basic research met to discuss the plethora of available animal models for studying exocrine pancreatic disease. In particular, the discussion focused on the challenges currently facing the field and potential solutions. That meeting culminated in this review, which describes the advantages and limitations of both common and infrequently used models of exocrine pancreatic disease, namely, pancreatitis and exocrine pancreatic cancer. The objective is to provide a comprehensive description of the available models but also to provide investigators with guidance in the application of these models to investigate both environmental and genetic contributions to exocrine pancreatic disease. The content covers both nongenic and genetically engineered models across multiple species (large and small). Recommendations for choosing the appropriate model as well as how to conduct and present results are provided.
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Affiliation(s)
- Jami L. Saloman
- Department of Neurobiology, Pittsburgh Center for Pain Research, University of Pittsburgh, Pittsburgh, PA
| | - Kathryn M. Albers
- Department of Neurobiology, Pittsburgh Center for Pain Research, University of Pittsburgh, Pittsburgh, PA
| | - Zobeida Cruz-Monserrate
- Division of Gastroenterology, Hepatology, and Nutrition; Comprehensive Cancer Center, The Ohio State University Wexner Medical Center, Columbus, OH
| | - Brian M. Davis
- Department of Neurobiology, Pittsburgh Center for Pain Research, University of Pittsburgh, Pittsburgh, PA
| | - Mouad Edderkaoui
- Basic and Translational Pancreas Research, Cedars-Sinai Medical Center, Los Angeles, CA
| | - Guido Eibl
- Department of Surgery, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, CA
| | - Ariel Y. Epouhe
- Department of Neurobiology, Pittsburgh Center for Pain Research, University of Pittsburgh, Pittsburgh, PA
| | - Jeremy Y. Gedeon
- Department of Neurobiology, Pittsburgh Center for Pain Research, University of Pittsburgh, Pittsburgh, PA
| | - Fred S. Gorelick
- Department of Internal Medicine, Section of Digestive Diseases & Department of Cell Biology Yale University School of Medicine; Veterans Affairs Connecticut Healthcare, West Haven, CT
| | - Paul J. Grippo
- Department of Medicine, Division of Gastroenterology and Hepatology, UI Cancer Center, University of Illinois at Chicago, Chicago, IL
| | - Guy E. Groblewski
- Department of Nutritional Sciences, University of Wisconsin, Madison, WI
| | | | - Keane K.Y. Lai
- Department of Pathology (National Medical Center), Department of Molecular Medicine (Beckman Research Institute), and Comprehensive Cancer Center, City of Hope, Duarte, CA
| | - Stephen J. Pandol
- Department of Surgery, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, CA
| | - Aliye Uc
- Stead Family Department of Pediatrics, University of Iowa, Stead Family Children’s Hospital, Iowa City, IA
| | - Li Wen
- Department of Pediatrics, Stanford University, Palo Alto, CA
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Merry TL, Petrov MS. The rise of genetically engineered mouse models of pancreatitis: A review of literature. Biomol Concepts 2018; 9:103-114. [DOI: 10.1515/bmc-2018-0011] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Accepted: 10/19/2018] [Indexed: 12/15/2022] Open
Abstract
AbstractPancreatitis is increasingly recognized as not merely a local inflammation of the pancreas but also a disease with high frequency of systemic sequelae. Current understanding of the cellular mechanisms that trigger it and affect the development of sequelae are limited. Genetically engineered mouse models can be a useful tool to study the pathophysiology of pancreatitis. This article gives an overview of the genetically engineered mouse models that spontaneously develop pancreatitis and discusses those that most closely replicate different pancreatitis hallmarks observed in humans.
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Affiliation(s)
- Troy L. Merry
- Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland, New Zealand
- Discipline of Nutrition, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Maxim S. Petrov
- Department of Surgery, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
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Cavelti-Weder C, Shtessel M, Reuss JE, Jermendy A, Yamada T, Caballero F, Bonner-Weir S, Weir GC. Pancreatic duct ligation after almost complete β-cell loss: exocrine regeneration but no evidence of β-cell regeneration. Endocrinology 2013; 154:4493-502. [PMID: 24029238 PMCID: PMC3836076 DOI: 10.1210/en.2013-1463] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
There has been great interest in the extent of β-cell regeneration after pancreatic duct ligation (PDL) and whether α- to β-cell conversion might account for β-cell regeneration after near-complete β-cell loss. To assess these questions, we established a PDL-model in adult male rats after almost complete beta-cell depletion achieved by giving a single high dose of streptozocin (STZ) in the fasted state. Because of the resultant severe diabetes, rats were given islet cell transplants to allow long-term follow-up. Although animals were followed up to 10 months, there was no meaningful β-cell regeneration, be it through replication, neogenesis, or α- to β-cell conversion. In contrast, the acinar cell compartment underwent massive changes with first severe acinar degeneration upon PDL injury followed by the appearance of pancreatic adipocytes, and finally near-complete reappearance of acini. We conclude that β-cells and acinar cells, although originating from the same precursors during development, have very distinct regenerative potentials in our PDL model in adult rats.
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Affiliation(s)
- Claudia Cavelti-Weder
- Section on Islet Cell and Regenerative Biology, Research Division, Joslin Diabetes Center, Department of Medicine, Harvard Medical School, One Joslin Place, Boston, Massachusetts 02215.
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Chen J, Yuan K, Mao X, Miano JM, Wu H, Chen Y. Serum response factor regulates bone formation via IGF-1 and Runx2 signals. J Bone Miner Res 2012; 27:1659-68. [PMID: 22434656 PMCID: PMC3977219 DOI: 10.1002/jbmr.1607] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Serum response factor (SRF) plays vital roles in numerous cellular processes; however, the physiological function of SRF in skeletal tissue remains unknown. In several organ systems, SRF regulates the expression of insulin-like growth factor-1 (IGF-1), which is crucial for normal development of mineralized skeleton and bone remodeling throughout life. Here, we show that conditional deletion of SRF in osteoblasts by osteocalcin-Cre generated viable mice with normal body size and body weight. Compared with normal siblings, osteoblast-specific SRF-deficient adult mice exhibited a marked decrease in bone mineral density and bone formation rate. Deletion of SRF in primary mouse calvarial osteoblasts reduced cell differentiation and mineralization in vitro. This was accompanied by a decrease in IGF-1 expression and secretion. Addition of IGF-1 in the culture media enhanced osteoblast differentiation in control cells and partially restored the mineralization defect of SRF-deficient cells, supporting an important role of SRF in regulating IGF-1 and IGF-1-mediated osteoblast differentiation. IGF-1-induced Akt activation was inhibited in SRF-deficient calvarial cells and enhanced in the SRF overexpressed cells. In addition, SRF deficiency decreased the transcriptional activity of Runx2, the key transcription factor for osteogenesis. Overexpression of SRF induced Runx2 transactivity in control cells and restored Runx2 transactivity in the SRF-deficient cells. Taken together, we conclude that SRF is important for IGF-1-induced osteoblast differentiation and mineralization via regulating IGF-1 expression and Runx2 transactivity.
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Affiliation(s)
- Jianfeng Chen
- Department of Pathology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Kaiyu Yuan
- Department of Pathology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Xia Mao
- Department of Pathology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Joseph M Miano
- Aab Cardiovascular Research Institute, School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA
| | - Hui Wu
- Department of Pediatric Dentistry, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Yabing Chen
- Department of Pathology, University of Alabama at Birmingham, Birmingham, AL, USA
- Veterans Administration Medical Center Research, Birmingham, AL, USA
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Thornley JA, Trask HW, Ringelberg CS, Ridley CJA, Wang S, Sal-Lari RC, Moore JH, Korc M, Tomlinson CR. SMAD4-dependent polysome RNA recruitment in human pancreatic cancer cells. Mol Carcinog 2011; 51:771-82. [PMID: 22965423 DOI: 10.1002/mc.20845] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2011] [Revised: 06/29/2011] [Accepted: 07/22/2011] [Indexed: 11/08/2022]
Abstract
Pancreatic cancer is the fourth leading cause of cancer death in the United States because most patients are diagnosed too late in the course of the disease to be treated effectively. Thus, there is a pressing need to more clearly understand how gene expression is regulated in cancer cells and to identify new biomarkers and therapeutic targets. Translational regulation is thought to occur primarily through non-SMAD directed signaling pathways. We tested the hypothesis that SMAD4-dependent signaling does play a role in the regulation of mRNA entry into polysomes and that novel candidate genes in pancreatic cancer could be identified using polysome RNA from the human pancreatic cancer cell line BxPC3 with or without a functional SMAD4 gene. We found that (i) differentially expressed whole cell and cytoplasm RNA levels are both poor predictors of polysome RNA levels; (ii) for a majority of RNAs, differential RNA levels are regulated independently in the nucleus, cytoplasm, and polysomes; (iii) for most of the remaining polysome RNA, levels are regulated via a "tagging" of the RNAs in the nucleus for rapid entry into the polysomes; (iv) a SMAD4-dependent pathway appears to indeed play a role in regulating mRNA entry into polysomes; and (v) a gene list derived from differentially expressed polysome RNA in BxPC3 cells generated new candidate genes and cell pathways potentially related to pancreatic cancer.
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Affiliation(s)
- Jessica A Thornley
- Norris Cotton Cancer Center, Dartmouth Hitchcock Medical Center, Lebanon, New Hampshire 03756, USA
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Sarkar A, Zhang M, Liu SH, Sarkar S, Brunicardi FC, Berger DH, Belaguli NS. Serum response factor expression is enriched in pancreatic β cells and regulates insulin gene expression. FASEB J 2011; 25:2592-603. [PMID: 21525490 DOI: 10.1096/fj.10-173757] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Serum response factor (SRF) is an essential regulator of myogenic and neurogenic genes and the ubiquitously expressed immediate-early genes. The purpose of this study is to determine SRF expression pattern in murine pancreas and examine the role of SRF in pancreatic gene expression. Immunohistochemical analysis of wild-type pancreas and LacZ staining of pancreas from SRF LacZ knock-in animals showed that SRF expression is restricted to β cells. SRF bound to the rat insulin promoter II (RIP II) serum response element, an element conserved in both rat I and murine I and II insulin promoters. SRF activated RIP II, and SRF binding to RIP II and the exon 5-encoded 64-aa subdomain of SRF was required for this activation. Transient or stable knockdown of SRF leads to down-regulation of insulin gene expression, suggesting that SRF is required for insulin gene expression. Further, SRF physically interacted with the pancreas and duodenum homeobox-1 (Pdx-1) and synergistically activated RIP II. Elevated glucose concentration down-regulated SRF binding to RIP II SRE, and this down-regulation was associated with decreased RIP II activity and increased SRF phosphorylation on serine 103. Together, our results demonstrate that SRF is a glucose concentration-sensitive regulator of insulin gene expression.
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Affiliation(s)
- Aloke Sarkar
- Michael E. DeBakey VA Medical Center, 2002 Holcombe Blvd., Houston, TX 77030, USA
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Honig G, Liou A, Berger M, German MS, Tecott LH. Precise pattern of recombination in serotonergic and hypothalamic neurons in a Pdx1-cre transgenic mouse line. J Biomed Sci 2010; 17:82. [PMID: 20950489 PMCID: PMC2966455 DOI: 10.1186/1423-0127-17-82] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2010] [Accepted: 10/17/2010] [Indexed: 11/25/2022] Open
Abstract
Background Multicellular organisms are characterized by a remarkable diversity of morphologically distinct and functionally specialized cell types. Transgenic techniques for the manipulation of gene expression in specific cellular populations are highly useful for elucidating the development and function of these cellular populations. Given notable similarities in developmental gene expression between pancreatic β-cells and serotonergic neurons, we examined the pattern of Cre-mediated recombination in the nervous system of a widely used mouse line, Pdx1-cre (formal designation, Tg(Ipf1-cre)89.1Dam), in which the expression of Cre recombinase is driven by regulatory elements upstream of the pdx1 (pancreatic-duodenal homeobox 1) gene. Methods Single (hemizygous) transgenic mice of the pdx1-creCre/0 genotype were bred to single (hemizygous) transgenic reporter mice (Z/EG and rosa26R lines). Recombination pattern was examined in offspring using whole-mount and sectioned histological preparations at e9.5, e10.5, e11.5, e16.5 and adult developmental stages. Results In addition to the previously reported pancreatic recombination, recombination in the developing nervous system and inner ear formation was observed. In the central nervous system, we observed a highly specific pattern of recombination in neuronal progenitors in the ventral brainstem and diencephalon. In the rostral brainstem (r1-r2), recombination occurred in newborn serotonergic neurons. In the caudal brainstem, recombination occurred in non-serotonergic cells. In the adult, this resulted in reporter expression in the vast majority of forebrain-projecting serotonergic neurons (located in the dorsal and median raphe nuclei) but in none of the spinal cord-projecting serotonergic neurons of the caudal raphe nuclei. In the adult caudal brainstem, reporter expression was widespread in the inferior olive nucleus. In the adult hypothalamus, recombination was observed in the arcuate nucleus and dorsomedial hypothalamus. Recombination was not observed in any other region of the central nervous system. Neuronal expression of endogenous pdx1 was not observed. Conclusions The Pdx1-cre mouse line, and the regulatory elements contained in the corresponding transgene, could be a valuable tool for targeted genetic manipulation of developing forebrain-projecting serotonergic neurons and several other unique neuronal sub-populations. These results suggest that investigators employing this mouse line for studies of pancreatic function should consider the possible contributions of central nervous system effects towards resulting phenotypes.
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Affiliation(s)
- Gerard Honig
- Neuroscience Graduate Program, University of California San Francisco, San Francisco, CA, USA.
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Abstract
Serum response factor (SRF) is a ubiquitously expressed transcription factor that binds to a DNA cis element known as the CArG box, which is found in the proximal regulatory regions of over 200 experimentally validated target genes. Genetic deletion of SRF is incompatible with life in a variety of animals from different phyla. In mice, loss of SRF throughout the early embryo results in gastrulation defects precluding analyses in individual organ systems. Genetic inactivation studies using conditional or inducible promoters directing the expression of the bacteriophage Cre recombinase have shown a vital role for SRF in such cellular processes as contractility, cell migration, synaptic activity, inflammation, and cell survival. A growing number of experimental and human diseases are associated with changes in SRF expression, suggesting that SRF has a role in the pathogenesis of disease. This review summarizes data from experimental model systems and human pathology where SRF expression is either deliberately or naturally altered.
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Abstract
Serum response factor (SRF) is a transcription factor that regulates many genes involved in cellular activities such as proliferation, migration, differentiation, angiogenesis, and apoptosis. Although it has only been known for about two decades, SRF has been studied extensively. To date, over a thousand SRF studies have been published, but it still remains a hot topic. Due to its critical role in mesoderm-derived tissues, most of the SRF studies focused on muscle structure/function, cardiovascular development/maintenance, and smooth muscle generation/repair. Recently, SRF has received more attention in the digestive field and several important discoveries have been made. This review will summarize what we have learned about SRF in the gastrointestinal tract and provide insights into possible future directions in this area.
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Inhibition of transforming growth factor beta signaling by halofuginone as a modality for pancreas fibrosis prevention. Pancreas 2009; 38:427-35. [PMID: 19188864 DOI: 10.1097/mpa.0b013e3181967670] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
OBJECTIVES Chronic pancreatitis is characterized by inflammation and fibrosis. We evaluated the efficacy of halofuginone, an inhibitor of collagen synthesis and myofibroblast activation, in preventing cerulein-induced pancreas fibrosis. METHODS Collagen synthesis was evaluated by in situ hybridization and staining. Levels of prolyl 4-hydroxylase beta (P4Hbeta), cytoglobin/stellate cell activation-associated protein (Cygb/STAP), transgelin, tissue inhibitors of metalloproteinases, serum response factor, transforming growth factor beta (TGFbeta), Smad3, and pancreatitis-associated protein 1 (PAP-1) were determined by immunohistochemistry. Metalloproteinase activity was evaluated by zymography. RESULTS Halofuginone prevented cerulein-dependent increase in collagen synthesis, collagen cross-linking enzyme P4Hbeta, Cygb/STAP, and tissue inhibitors of metalloproteinase 2. Halofuginone did not affect TGFbeta levels in cerulein-treated mice but inhibited serum response factor synthesis and Smad3 phosphorylation. In culture, halofuginone inhibited pancreatic stellate cell (PSC) proliferation and TGFbeta-dependent increase in Cygb/STAP and transgelin synthesis and metalloproteinase 2 activity. Halofuginone increased c-Jun N-terminal kinase phosphorylation in PSCs derived from cerulein-treated mice. Halofuginone prevented the increase in acinar cell proliferation and further increased the cerulein-dependent PAP-1 synthesis. CONCLUSIONS Halofuginone inhibits Smad3 phosphorylation and increases c-Jun N-terminal kinase phosphorylation, leading to the inhibition of PSC activation and consequent prevention of fibrosis. Halofuginone increased the synthesis of PAP-1, which further reduces pancreas fibrosis. Thus, halofuginone might serve as a novel therapy for pancreas fibrosis.
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Bonal C, Thorel F, Ait-Lounis A, Reith W, Trumpp A, Herrera PL. Pancreatic inactivation of c-Myc decreases acinar mass and transdifferentiates acinar cells into adipocytes in mice. Gastroenterology 2009; 136:309-319.e9. [PMID: 19022256 DOI: 10.1053/j.gastro.2008.10.015] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2008] [Revised: 09/29/2008] [Accepted: 10/02/2008] [Indexed: 12/17/2022]
Abstract
BACKGROUND & AIMS The pancreatic mass is determined by the coordinated expansion and differentiation of progenitor cells and is maintained via tight control of cell replacement rates. The basic helix-loop-helix transcription factor c-Myc is one of the main regulators of these processes in many organs. We studied the requirement of c-Myc in controlling the generation and maintenance of pancreatic mass. METHODS We conditionally inactivated c-Myc in Pdx1+ pancreatic progenitor cells. Pancreata of mice lacking c-Myc (c-Myc(P-/-) mice) were analyzed during development and ageing. RESULTS Pancreatic growth in c-Myc(P-/-) mice was impaired starting on E12.5, in early primordia, because of decreased proliferation and altered differentiation of exocrine progenitors; islet progenitors were spared. Acinar cell maturation was defective in the adult hypotrophic pancreas, which hampered exocrine mass maintenance in aged animals. From 2 to 10 months of age, the c-Myc(P-/-) pancreas was progressively remodeled without inflammatory injury. Loss of acinar cells increased with time, concomitantly with adipose tissue accumulation. Using a genetic cell lineage tracing analysis, we demonstrated that pancreatic adipose cells were derived directly from transdifferentiating acinar cells. This epithelial-to-mesenchyme transition was also observed in normal aged specimens and in pancreatitis. CONCLUSIONS These results provide evidence indicating that c-Myc activity is required for growth and maturation of the exocrine pancreas, and sheds new light on the ontogeny of pancreatic adipose cells in processes of organ degenerescence and tissue involution.
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Affiliation(s)
- Claire Bonal
- Department of Genetic Medicine and Development, University of Geneva Medical School, Geneva, Switzerland
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Mericskay M, Blanc J, Tritsch E, Moriez R, Aubert P, Neunlist M, Feil R, Li Z. Inducible mouse model of chronic intestinal pseudo-obstruction by smooth muscle-specific inactivation of the SRF gene. Gastroenterology 2007; 133:1960-70. [PMID: 18054567 DOI: 10.1053/j.gastro.2007.09.010] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2007] [Accepted: 08/30/2007] [Indexed: 01/20/2023]
Abstract
BACKGROUND & AIMS Serum response factor (SRF) regulates the expression of muscle genes and immediate early genes. We investigated the consequences of inactivating this transcription factor SRF in adult gastrointestinal smooth muscle cells. METHODS SRF-floxed mice were crossed with SM-CreER(T2)(ki) mice expressing a tamoxifen-inducible recombinase in smooth muscle cells. Tamoxifen was injected into 12-week-old animals to activate the CreER(T2) and excise the SRF gene. RESULTS SRF was down-regulated in the smooth muscle cells of the gastrointestinal tract, urinary bladder, and aorta. The mutant mice developed severe dilation of the intestinal tract associated with food stasis and air-fluid levels in the lumen 13 days after tamoxifen treatment. Mutant mice displayed cachexia and died between days 13 and 22. The dilation was associated with a thinning of the muscularis propria and was also observed in the urinary bladder. Ex vivo colonic contraction induced by electric field stimulation and carbachol was impaired in the mutant mice before the occurrence of the dilation phenotype. The expression of several genes, including those encoding smooth muscle actin, the heavy chain of smooth muscle myosin, and smoothelin, was 60% to 70% lower in mutants than in controls, and mutants also had a lower F/G actin ratio. CONCLUSIONS SRF plays a central role in maintaining visceral smooth muscle contractile function in adults. Mice with a smooth muscle cell-specific SRF mutation develop a severe motility disorder resembling chronic intestinal pseudo-obstruction in humans and may be used as an inducible model of this disorder.
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Affiliation(s)
- Mathias Mericskay
- Pierre & Marie Curie University Paris 6, Paris, France; CNRS, UMR7079 Physiology and Physiopathology, Paris, France.
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Ramey G, Faye A, Durel B, Viollet B, Vaulont S. Iron overload inHepc1−/−mice is not impairing glucose homeostasis. FEBS Lett 2007; 581:1053-7. [PMID: 17316628 DOI: 10.1016/j.febslet.2007.02.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2006] [Revised: 01/25/2007] [Accepted: 02/04/2007] [Indexed: 12/28/2022]
Abstract
Diabetes Mellitus is found with increasing frequency in iron overload patients with hemochromatosis. In these conditions, the pancreas shows predominant iron overload in acini but also islet beta-cells. We assess glucose homeostasis status in iron-overloaded hepcidin-deficient mice. These mice presented with heavy pancreatic iron deposits but only in the acini. The beta-cell function was found unaffected with a normal production and secretion of insulin. The mutant mice were not diabetic, responded as the control group to glucose and insulin challenges, with no alteration of insulin signalling in the muscle and the liver. These results indicate that, beta-cells iron deposits-induced decreased insulin secretory capacity might be of primary importance to trigger diabetes in hemochromatosic patients.
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Affiliation(s)
- G Ramey
- Institut Cochin, Département Endocrinologie Métabolisme et Cancer, Paris, F-75014, France
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Cano DA, Sekine S, Hebrok M. Primary cilia deletion in pancreatic epithelial cells results in cyst formation and pancreatitis. Gastroenterology 2006; 131:1856-69. [PMID: 17123526 DOI: 10.1053/j.gastro.2006.10.050] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2006] [Accepted: 10/12/2006] [Indexed: 12/15/2022]
Abstract
BACKGROUND & AIMS Defects in cilia formation or function have been implicated in several human genetic diseases, including polycystic kidney disease (PKD), Bardet-Biedl syndrome, and primary ciliary dyskinesia. Pancreatic lesions are found in approximately 10% of PKD patients, suggesting a connection between cilia defects and pancreatic pathologies. Here, we investigate the role of cilia in pancreas formation and function by analyzing mice that lack cilia in pancreatic cells. METHODS Using Cre/lox technology, we conditionally inactivated Kif3a, the gene encoding for a subunit of the kinesin-2 complex that is essential for cilia formation, in pancreatic epithelia. Kif3a mice were studied by immunohistochemical and biochemical methods to assess the morphology and differentiation status of pancreatic cells. RESULTS Tissue-specific loss of Kif3a in pancreatic cells resulted in severe pancreatic abnormalities including acinar-to-ductal metaplasia, fibrosis, and lipomatosis. Ductal metaplasia appears to be due to expansion of ductal cells rather than transdifferentiation of acinar cells. Cyst formation, aberrant ductal morphology, and extensive fibrosis associated with severe adhesion to adjacent organs were commonly observed in aged Kif3a mutant mice. Deletion of Kif3a using different pancreas-specific Cre strains suggests that these pancreatic phenotypes might be caused by the absence of cilia in ductal cells. Activation of transforming growth factor beta and Mitogen-activated protein kinase kinase/extracellular signal-regulated kinase (MEK/ERK) pathways may play a role in these phenotypes. CONCLUSIONS These results demonstrate that the absence of cilia in pancreatic cells produces pancreatic lesions that resemble those found in patients with chronic pancreatitis or cystic fibrosis.
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Affiliation(s)
- David A Cano
- Diabetes Center, Department of Medicine, University of California San Francisco, California 94143, USA
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