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Onufer EJ, Han YH, Courtney C, Steinberger A, Tecos M, Sutton S, Sescleifer A, Ou J, Sanguinetti Czepielewski R, Randolph GJ, Warner BW. Liver injury after small bowel resection is prevented in obesity-resistant 129S1/SvImJ mice. Am J Physiol Gastrointest Liver Physiol 2021; 320:G907-G918. [PMID: 33729834 PMCID: PMC8202193 DOI: 10.1152/ajpgi.00284.2020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Intestinal failure-associated liver disease is a major morbidity associated with short bowel syndrome. We sought to determine if the obesity-resistant mouse strain (129S1/SvImJ) conferred protection from liver injury after small bowel resection (SBR). Using a parenteral nutrition-independent model of resection-associated liver injury, C57BL/6J and 129S1/SvImJ mice underwent a 50% proximal SBR or sham operation. At postoperative week 10, hepatic steatosis, fibrosis, and cholestasis were assessed. Hepatic and systemic inflammatory pathways were evaluated using oxidative markers and abundance of tissue macrophages. Potential mechanisms of endotoxin resistance were also explored. Serum lipid levels were elevated in all mouse lines. Hepatic triglyceride levels were no different between mouse strains, but there was an increased accumulation of free fatty acids in the C57BL/6J mice. Histological and serum markers of hepatic fibrosis, steatosis, and cholestasis were significantly elevated in resected C57BL/6J SBR mice as well as oxidative stress markers and macrophage recruitment in both the liver and visceral white fat in C57BL/6J mice compared with sham controls and the 129S1/SvImJ mouse line. Serum endotoxin levels were significantly elevated in C57BL/6J mice with significant elevation of hepatic TLR4 and reduction in PPARα expression levels. Despite high levels of serum lipids, 129S1/SvImJ mice did not develop liver inflammation, fibrosis, or cholestasis after SBR, unlike C57BL/6J mice. These data suggest that the accumulation of hepatic free fatty acids as well as increased endotoxin-driven inflammatory pathways through PPARα and TLR4 contribute to the liver injury seen in C57BL/6J mice with short bowel syndrome.NEW & NOTEWORTHY Unlike C57BL/6 mice, the 129S1/SvImJ strain is resistant to liver inflammation and injury after small bowel resection. These disparate outcomes are likely due to the accumulation of hepatic free fatty acids as well as increased endotoxin-driven inflammatory pathways through PPARα and TLR4 in C57BL/6 mice with short bowel syndrome.
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Affiliation(s)
- Emily J. Onufer
- 1Division of Pediatric Surgery, Department of Surgery, Washington University School of Medicine, St. Louis, Missouri
| | - Yong-Hyun Han
- 2Laboratory of Pathology and Physiology, College of Pharmacy,
Kangwon National University, Chuncheon, South Korea,3Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri
| | - Cathleen Courtney
- 1Division of Pediatric Surgery, Department of Surgery, Washington University School of Medicine, St. Louis, Missouri
| | - Allie Steinberger
- 1Division of Pediatric Surgery, Department of Surgery, Washington University School of Medicine, St. Louis, Missouri
| | - Maria Tecos
- 1Division of Pediatric Surgery, Department of Surgery, Washington University School of Medicine, St. Louis, Missouri
| | - Stephanie Sutton
- 1Division of Pediatric Surgery, Department of Surgery, Washington University School of Medicine, St. Louis, Missouri
| | - Anne Sescleifer
- 1Division of Pediatric Surgery, Department of Surgery, Washington University School of Medicine, St. Louis, Missouri
| | - Jocelyn Ou
- 1Division of Pediatric Surgery, Department of Surgery, Washington University School of Medicine, St. Louis, Missouri
| | | | - Gwendalyn J. Randolph
- 3Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri
| | - Brad W. Warner
- 1Division of Pediatric Surgery, Department of Surgery, Washington University School of Medicine, St. Louis, Missouri
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Berlin P, Reiner J, Wobar J, Bannert K, Glass Ä, Walter M, Bastian M, Willenberg HS, Vollmar B, Klar E, Seidler U, Lamprecht G, Witte M. Villus Growth, Increased Intestinal Epithelial Sodium Selectivity, and Hyperaldosteronism Are Mechanisms of Adaptation in a Murine Model of Short Bowel Syndrome. Dig Dis Sci 2019; 64:1158-1170. [PMID: 30569336 PMCID: PMC6548203 DOI: 10.1007/s10620-018-5420-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 12/07/2018] [Indexed: 12/09/2022]
Abstract
BACKGROUND Short bowel syndrome results from extensive small bowel resection and induces adaptation of the remaining intestine. Ileocecal resection (ICR) is the most frequent situation in humans. Villus hypertrophy is one hallmark of mucosal adaptation, but the functional mechanisms of mucosal adaptation are incompletely understood. AIMS The aim of the study was to characterize a clinically relevant model of short bowel syndrome but not intestinal failure in mice and to identify outcome predictors and mechanisms of adaptation. METHODS Male C57BL6/J mice underwent 40% ICR and were followed for 7 or 14 days. Small bowel transection served as control. All mice underwent autopsy. Survival, body weight, wellness score, stool water content, plasma aldosterone concentrations, and paracellular permeability were recorded. RESULTS Unlike controls, resected mice developed significant diarrhea with increased stool water. This was accompanied by sustained weight loss throughout follow-up. Villus length increased but did not correlate positively with adaptation. Plasma aldosterone concentrations correlated inversely with body weight at day 14. After ICR, intestinal epithelial (i.e., tight junctional) sodium permeability was increased. CONCLUSIONS 40% ICR results in moderate to severe short bowel syndrome. Successful adaptation to the short bowel situation involves villus elongation but does not correlate with the degree of villus elongation alone. In addition, increased intestinal epithelial sodium permeability facilitates sodium-coupled solute transport. Hyperaldosteronism correlates with the severity of weight loss, indicates volume depletion, and counterregulates water loss.
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Affiliation(s)
- Peggy Berlin
- Division of Gastroenterology, Department of Medicine II, Rostock University Medical Center, Ernst-Heydemann-Str. 6, 18057 Rostock, Germany
| | - Johannes Reiner
- Division of Gastroenterology, Department of Medicine II, Rostock University Medical Center, Ernst-Heydemann-Str. 6, 18057 Rostock, Germany
| | - Jakob Wobar
- Division of Gastroenterology, Department of Medicine II, Rostock University Medical Center, Ernst-Heydemann-Str. 6, 18057 Rostock, Germany
| | - Karen Bannert
- Division of Gastroenterology, Department of Medicine II, Rostock University Medical Center, Ernst-Heydemann-Str. 6, 18057 Rostock, Germany
| | - Änne Glass
- Institute for Biostatistics and Informatics in Medicine and Ageing Research, Rostock University Medical Center, Ernst-Heydemann-Str. 8, 18057 Rostock, Germany
| | - Michael Walter
- Institute for Clinical Chemistry and Laboratory Medicine, Rostock University Medical Center, Ernst-Heydemann-Str. 6, 18057 Rostock, Germany
| | - Manuela Bastian
- Institute for Clinical Chemistry and Laboratory Medicine, Rostock University Medical Center, Ernst-Heydemann-Str. 6, 18057 Rostock, Germany
| | - Holger Sven Willenberg
- Division of Endocrinology and Metabolism, Department of Medicine II, Rostock University Medical Center, Ernst-Heydemann-Str. 6, 18057 Rostock, Germany
| | - Brigitte Vollmar
- Institute of Experimental Surgery, Rostock University Medical Center, Schillingallee 69a, 18057 Rostock, Germany
| | - Ernst Klar
- Department of General, Thoracic, Vascular and Transplantation Surgery, Rostock University Medical Center, Schillingallee 35, 18057 Rostock, Germany
| | - Ursula Seidler
- Department of Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany
| | - Georg Lamprecht
- Division of Gastroenterology, Department of Medicine II, Rostock University Medical Center, Ernst-Heydemann-Str. 6, 18057 Rostock, Germany
| | - Maria Witte
- Department of General, Thoracic, Vascular and Transplantation Surgery, Rostock University Medical Center, Schillingallee 35, 18057 Rostock, Germany
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Schall KA, Thornton ME, Isani M, Holoyda KA, Hou X, Lien CL, Grubbs BH, Grikscheit TC. Short bowel syndrome results in increased gene expression associated with proliferation, inflammation, bile acid synthesis and immune system activation: RNA sequencing a zebrafish SBS model. BMC Genomics 2017; 18:23. [PMID: 28118819 PMCID: PMC5264326 DOI: 10.1186/s12864-016-3433-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Accepted: 12/19/2016] [Indexed: 01/19/2023] Open
Abstract
Background Much of the morbidity associated with short bowel syndrome (SBS) is attributed to effects of decreased enteral nutrition and administration of total parenteral nutrition (TPN). We hypothesized that acute SBS alone has significant effects on gene expression beyond epithelial proliferation, and tested this in a zebrafish SBS model. Methods In a model of SBS in zebrafish (laparotomy, proximal stoma, distal ligation, n = 29) or sham (laparotomy alone, n = 28) surgery, RNA-Seq was performed after 2 weeks. The proximal intestine was harvested and RNA isolated. The three samples from each group with the highest amount of RNA were spiked with external RNA controls consortium (ERCC) controls, sequenced and aligned to reference genome with gene ontology (GO) enrichment analysis performed. Gene expression of ctnnb1, ccnb1, ccnd1, cyp7a1a, dkk3, ifng1-2, igf2a, il1b, lef1, nos2b, saa1, stat3, tnfa and wnt5a were confirmed to be elevated in SBS by RT-qPCR. Results RNA-seq analysis identified 1346 significantly upregulated genes and 678 significantly downregulated genes in SBS zebrafish intestine compared to sham with Ingenuity analysis. The upregulated genes were involved in cell proliferation, acute phase response signaling, innate and adaptive immunity, bile acid regulation, production of nitric oxide and reactive oxygen species, cellular barrier and coagulation. The downregulated genes were involved in folate synthesis, gluconeogenesis, glycogenolysis, fatty-acid oxidation and activation and drug and steroid metabolism. RT-qPCR confirmed gene expression differences from RNA-Sequencing. Conclusion Changes of gene expression after 2 weeks of SBS indicate complex and extensive alterations of multiple pathways, some previously implicated as effects of TPN. The systemic sequelae of SBS alone are significant and indicate multiple targets for investigating future therapies. Electronic supplementary material The online version of this article (doi:10.1186/s12864-016-3433-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Kathy A Schall
- Division of Pediatric Surgery and Developmental Biology and Regenerative Medicine, Saban Research Institute, Children's Hospital Los Angeles and USC Keck School of Medicine, Los Angeles, CA, 90027, USA
| | - Matthew E Thornton
- Department of Obstetrics and Gynecology, Division of Maternal Fetal Medicine, Saban Research Institute, Children's Hospital Los Angeles and USC Keck School of Medicine, Los Angeles, CA, 90027, USA
| | - Mubina Isani
- Division of Pediatric Surgery and Developmental Biology and Regenerative Medicine, Saban Research Institute, Children's Hospital Los Angeles and USC Keck School of Medicine, Los Angeles, CA, 90027, USA
| | - Kathleen A Holoyda
- Division of Pediatric Surgery and Developmental Biology and Regenerative Medicine, Saban Research Institute, Children's Hospital Los Angeles and USC Keck School of Medicine, Los Angeles, CA, 90027, USA
| | - Xiaogang Hou
- Division of Pediatric Surgery and Developmental Biology and Regenerative Medicine, Saban Research Institute, Children's Hospital Los Angeles and USC Keck School of Medicine, Los Angeles, CA, 90027, USA
| | - Ching-Ling Lien
- Division of Cardiothoracic Surgery, Saban Research Institute, Children's Hospital Los Angeles and USC Keck School of Medicine, Los Angeles, CA, 90027, USA
| | - Brendan H Grubbs
- Department of Obstetrics and Gynecology, Division of Maternal Fetal Medicine, Saban Research Institute, Children's Hospital Los Angeles and USC Keck School of Medicine, Los Angeles, CA, 90027, USA
| | - Tracy C Grikscheit
- Division of Pediatric Surgery and Developmental Biology and Regenerative Medicine, Saban Research Institute, Children's Hospital Los Angeles and USC Keck School of Medicine, Los Angeles, CA, 90027, USA. .,Department of Surgery, Children's Hospital Los Angeles, 4650 Sunset Blvd, Mailstop 100, Los Angeles, CA, 90027, USA.
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Schall KA, Holoyda KA, Grant CN, Levin DE, Torres ER, Maxwell A, Pollack HA, Moats RA, Frey MR, Darehzereshki A, Al Alam D, Lien C, Grikscheit TC. Adult zebrafish intestine resection: a novel model of short bowel syndrome, adaptation, and intestinal stem cell regeneration. Am J Physiol Gastrointest Liver Physiol 2015; 309:G135-45. [PMID: 26089336 PMCID: PMC4525108 DOI: 10.1152/ajpgi.00311.2014] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Accepted: 05/28/2015] [Indexed: 01/31/2023]
Abstract
Loss of significant intestinal length from congenital anomaly or disease may lead to short bowel syndrome (SBS); intestinal failure may be partially offset by a gain in epithelial surface area, termed adaptation. Current in vivo models of SBS are costly and technically challenging. Operative times and survival rates have slowed extension to transgenic models. We created a new reproducible in vivo model of SBS in zebrafish, a tractable vertebrate model, to facilitate investigation of the mechanisms of intestinal adaptation. Proximal intestinal diversion at segment 1 (S1, equivalent to jejunum) was performed in adult male zebrafish. SBS fish emptied distal intestinal contents via stoma as in the human disease. After 2 wk, S1 was dilated compared with controls and villus ridges had increased complexity, contributing to greater villus epithelial perimeter. The number of intervillus pockets, the intestinal stem cell zone of the zebrafish increased and contained a higher number of bromodeoxyuridine (BrdU)-labeled cells after 2 wk of SBS. Egf receptor and a subset of its ligands, also drivers of adaptation, were upregulated in SBS fish. Igf has been reported as a driver of intestinal adaptation in other animal models, and SBS fish exposed to a pharmacological inhibitor of the Igf receptor failed to demonstrate signs of intestinal adaptation, such as increased inner epithelial perimeter and BrdU incorporation. We describe a technically feasible model of human SBS in the zebrafish, a faster and less expensive tool to investigate intestinal stem cell plasticity as well as the mechanisms that drive intestinal adaptation.
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Affiliation(s)
- K. A. Schall
- 1Division of Pediatric Surgery, Children's Hospital Los Angeles, Keck School of Medicine at University of Southern California, Los Angeles, California;
| | - K. A. Holoyda
- 1Division of Pediatric Surgery, Children's Hospital Los Angeles, Keck School of Medicine at University of Southern California, Los Angeles, California;
| | - C. N. Grant
- 1Division of Pediatric Surgery, Children's Hospital Los Angeles, Keck School of Medicine at University of Southern California, Los Angeles, California;
| | - D. E. Levin
- 1Division of Pediatric Surgery, Children's Hospital Los Angeles, Keck School of Medicine at University of Southern California, Los Angeles, California;
| | - E. R. Torres
- 1Division of Pediatric Surgery, Children's Hospital Los Angeles, Keck School of Medicine at University of Southern California, Los Angeles, California;
| | - A. Maxwell
- 2Developmental Biology and Regenerative Medicine Program, The Saban Research Institute, Children's Hospital Los Angeles, Keck School of Medicine at University of Southern California, Los Angeles, California;
| | - H. A. Pollack
- 3Department of Radiology, Children's Hospital Los Angeles, Keck School of Medicine at University of Southern California, Los Angeles, California;
| | - R. A. Moats
- 3Department of Radiology, Children's Hospital Los Angeles, Keck School of Medicine at University of Southern California, Los Angeles, California;
| | - M. R. Frey
- 2Developmental Biology and Regenerative Medicine Program, The Saban Research Institute, Children's Hospital Los Angeles, Keck School of Medicine at University of Southern California, Los Angeles, California; ,4Department of Pediatrics and Department of Biochemistry and Molecular Biology, Keck School of Medicine at University of Southern California, Los Angeles, California; and
| | - A. Darehzereshki
- 2Developmental Biology and Regenerative Medicine Program, The Saban Research Institute, Children's Hospital Los Angeles, Keck School of Medicine at University of Southern California, Los Angeles, California;
| | - D. Al Alam
- 1Division of Pediatric Surgery, Children's Hospital Los Angeles, Keck School of Medicine at University of Southern California, Los Angeles, California;
| | - C. Lien
- 2Developmental Biology and Regenerative Medicine Program, The Saban Research Institute, Children's Hospital Los Angeles, Keck School of Medicine at University of Southern California, Los Angeles, California; ,5Department of Cardiothoracic Surgery, Children's Hospital Los Angeles, Keck School of Medicine at University of Southern California, Los Angeles, California
| | - T. C. Grikscheit
- 1Division of Pediatric Surgery, Children's Hospital Los Angeles, Keck School of Medicine at University of Southern California, Los Angeles, California; ,2Developmental Biology and Regenerative Medicine Program, The Saban Research Institute, Children's Hospital Los Angeles, Keck School of Medicine at University of Southern California, Los Angeles, California;
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5
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Diaz-Miron J, Sun R, Choi P, Sommovilla J, Guo J, Erwin CR, Mei J, Scott Worthen G, Warner BW. The effect of impaired angiogenesis on intestinal function following massive small bowel resection. J Pediatr Surg 2015; 50:948-53. [PMID: 25818317 PMCID: PMC4439276 DOI: 10.1016/j.jpedsurg.2015.03.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Accepted: 03/10/2015] [Indexed: 01/01/2023]
Abstract
PURPOSE Intestinal adaptation involves villus lengthening, crypt deepening, and increased capillary density following small bowel resection (SBR). Mice lacking the proangiogenic chemokine CXCL5 have normal structural adaptation but impaired angiogenesis. This work evaluates the impact of incomplete adaptive angiogenesis on the functional capacity of the intestine after SBR. METHODS CXCL5 knockout (KO) and C57BL/6 wild-type (WT) mice underwent 50% SBR. Magnetic resonance imaging measured weekly body composition. Intestinal absorptive capacity was evaluated through fecal fat analysis. Gene expression profiles for select macronutrient transporters were measured via RT-PCR. Postoperative crypt and villus measurements were assessed for structural adaptation. Submucosal capillary density was measured through CD31 immunohistochemistry. RESULTS Comparable postoperative weight gain occurred initially. Diminished weight gain, impaired fat absorption, and elevated steatorrhea occurred in KO mice after instituting high-fat diet. Greater postoperative upregulation of ABCA1 fat transporter occurred in WT mice, while PEPT1 protein transporter was significantly downregulated in KO mice. KO mice had impaired angiogenesis but intact structural adaptation. CONCLUSION After SBR, KO mice display an inefficient intestinal absorption profile with perturbed macronutrient transporter expression, impaired fat absorption, and slower postoperative weight gain. In addition to longer villi and deeper crypts, an intact angiogenic response may be required to achieve functional adaptation to SBR.
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Affiliation(s)
- Jose Diaz-Miron
- Division of Pediatric Surgery, St Louis Children's Hospital, Department of Surgery, Washington University School of Medicine, St Louis, MO
| | - Raphael Sun
- Division of Pediatric Surgery, St Louis Children's Hospital, Department of Surgery, Washington University School of Medicine, St Louis, MO
| | - Pamela Choi
- Division of Pediatric Surgery, St Louis Children's Hospital, Department of Surgery, Washington University School of Medicine, St Louis, MO
| | - Joshua Sommovilla
- Division of Pediatric Surgery, St Louis Children's Hospital, Department of Surgery, Washington University School of Medicine, St Louis, MO
| | - Jun Guo
- Division of Pediatric Surgery, St Louis Children's Hospital, Department of Surgery, Washington University School of Medicine, St Louis, MO
| | - Christopher R Erwin
- Division of Pediatric Surgery, St Louis Children's Hospital, Department of Surgery, Washington University School of Medicine, St Louis, MO
| | - Junjie Mei
- Division of Neonatology, The Children's Hospital of Philadelphia, Philadelphia, PA
| | - G Scott Worthen
- Division of Neonatology, The Children's Hospital of Philadelphia, Philadelphia, PA
| | - Brad W Warner
- Division of Pediatric Surgery, St Louis Children's Hospital, Department of Surgery, Washington University School of Medicine, St Louis, MO.
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Sangild PT, Ney DM, Sigalet DL, Vegge A, Burrin D. Animal models of gastrointestinal and liver diseases. Animal models of infant short bowel syndrome: translational relevance and challenges. Am J Physiol Gastrointest Liver Physiol 2014; 307:G1147-68. [PMID: 25342047 PMCID: PMC4269678 DOI: 10.1152/ajpgi.00088.2014] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Intestinal failure (IF), due to short bowel syndrome (SBS), results from surgical resection of a major portion of the intestine, leading to reduced nutrient absorption and need for parenteral nutrition (PN). The incidence is highest in infants and relates to preterm birth, necrotizing enterocolitis, atresia, gastroschisis, volvulus, and aganglionosis. Patient outcomes have improved, but there is a need to develop new therapies for SBS and to understand intestinal adaptation after different diseases, resection types, and nutritional and pharmacological interventions. Animal studies are needed to carefully evaluate the cellular mechanisms, safety, and translational relevance of new procedures. Distal intestinal resection, without a functioning colon, results in the most severe complications and adaptation may depend on the age at resection (preterm, term, young, adult). Clinically relevant therapies have recently been suggested from studies in preterm and term PN-dependent SBS piglets, with or without a functional colon. Studies in rats and mice have specifically addressed the fundamental physiological processes underlying adaptation at the cellular level, such as regulation of mucosal proliferation, apoptosis, transport, and digestive enzyme expression, and easily allow exogenous or genetic manipulation of growth factors and their receptors (e.g., glucagon-like peptide 2, growth hormone, insulin-like growth factor 1, epidermal growth factor, keratinocyte growth factor). The greater size of rats, and especially young pigs, is an advantage for testing surgical procedures and nutritional interventions (e.g., PN, milk diets, long-/short-chain lipids, pre- and probiotics). Conversely, newborn pigs (preterm or term) and weanling rats provide better insights into the developmental aspects of treatment for SBS in infants owing to their immature intestines. The review shows that a balance among practical, economical, experimental, and ethical constraints will determine the choice of SBS model for each clinical or basic research question.
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Affiliation(s)
- Per T. Sangild
- 1Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Frederiksberg, Denmark; ,2Department of Paediatrics and Adolescent Medicine, Rigshospitalet, Copenhagen, Denmark;
| | - Denise M. Ney
- 3Department of Nutritional Sciences, University of Wisconsin-Madison, Madison, Wisconsin;
| | | | - Andreas Vegge
- 1Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Frederiksberg, Denmark; ,5Diabetes Pharmacology, Novo Nordisk, Måløv, Denmark; and
| | - Douglas Burrin
- 6USDA-ARS Children's Nutrition Research Center, Baylor College of Medicine, Houston, Texas
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Rowland KJ, Diaz-Miron J, Guo J, Erwin CR, Mei J, Worthen GS, Warner BW. CXCL5 is required for angiogenesis, but not structural adaptation after small bowel resection. J Pediatr Surg 2014; 49:976-80; discussion 980. [PMID: 24888846 PMCID: PMC4044536 DOI: 10.1016/j.jpedsurg.2014.01.034] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Accepted: 01/27/2014] [Indexed: 01/14/2023]
Abstract
PURPOSE Intestinal adaptation is the compensatory response to massive small bowel resection (SBR) and characterized by lengthening of villi and deepening of crypts, resulting in increased mucosal surface area. Previous studies have demonstrated increased villus capillary blood vessel density after SBR, suggesting a role for angiogenesis in the development of resection-induced adaptation. Since we have previously shown enhanced expression of the proangiogenic chemokine CXCL5 after SBR, the purpose of this study was to determine the effect of disrupted CXCL5 expression on intestinal adaptation. METHODS CXCL5 knockout (KO) and C57BL/6 wild type (WT) mice were subjected to either a 50% proximal SBR or sham operation. Ileal tissue was harvested on postoperative day 7. To assess for adaptation, villus height and crypt depth were measured. Submucosal capillary density was measured by CD31 immunohistochemistry. RESULTS Both CXCL5-KO and WT mice demonstrated normal structural features of adaptation. Submucosal capillary density increased in the WT but not in the KO mice following SBR. CONCLUSION CXCL5 is required for increased intestinal angiogenesis during resection-induced adaptation. Since adaptive villus growth occurs despite impaired CXCL5 expression and enhanced angiogenesis, this suggests that the growth of new blood vessels is not needed for resection-induced mucosal surface area expansion following massive SBR.
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Affiliation(s)
- Kathryn J. Rowland
- Division of Pediatric Surgery, St Louis Children’s Hospital, Department of Surgery, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Jose Diaz-Miron
- Division of Pediatric Surgery, St Louis Children’s Hospital, Department of Surgery, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Jun Guo
- Division of Pediatric Surgery, St Louis Children’s Hospital, Department of Surgery, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Christopher R. Erwin
- Division of Pediatric Surgery, St Louis Children’s Hospital, Department of Surgery, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Junjie Mei
- Division of Neonatology, The Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - G. Scott Worthen
- Division of Neonatology, The Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Brad W. Warner
- Division of Pediatric Surgery, St Louis Children’s Hospital, Department of Surgery, Washington University School of Medicine, St Louis, MO 63110, USA
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8
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Rowland KJ, Yao J, Wang L, Erwin CR, Maslov KI, Wang LV, Warner BW. Up-regulation of hypoxia-inducible factor 1 alpha and hemodynamic responses following massive small bowel resection. J Pediatr Surg 2013; 48:1330-9. [PMID: 23845627 PMCID: PMC3755458 DOI: 10.1016/j.jpedsurg.2013.03.031] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2013] [Accepted: 03/08/2013] [Indexed: 02/07/2023]
Abstract
PURPOSE Massive small bowel resection (SBR) results in an adaptive response within the remnant bowel. We have previously shown an immediate reduction in intestinal blood flow and oxygen saturation (sO2) after SBR. We therefore sought to determine the duration of resection-induced intestinal hypoxia and expression of hypoxia-inducible factors (HIFs) following SBR. METHODS C57B6 mice were subjected to 50% proximal SBR or a sham procedure. Photoacoustic microscopy (PAM) was used to measure blood flow and sO2 on postoperative days (PODs) 1, 3, and 7. Ileal tissue was harvested 6h postoperatively and on PODs 1 and 2, and HIF1α, HIF2α, and VEGF mRNA expression were assessed via RT-PCR. A p value of less than 0.05 was considered significant. RESULTS Following SBR, reduction in intestinal blood flow persists for 24h and is followed with hyperemia by POD 3. The immediate reduction in venous sO2 and increased tissue oxygen utilization continued through POD 7. Enhanced expression of HIF1α was demonstrated 6h following SBR. CONCLUSION Massive SBR results in an immediate relative hypoxic state within the remnant bowel with early enhanced expression of HIF1α. On POD 7, increased tissue oxygen extraction and elevated blood flow persist in the adapting intestine.
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Affiliation(s)
- Kathryn J. Rowland
- Division of Pediatric Surgery, St Louis Children's Hospital, Department of Surgery, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Junjie Yao
- Optical Imaging Laboratory, Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Lidai Wang
- Optical Imaging Laboratory, Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Christopher R. Erwin
- Division of Pediatric Surgery, St Louis Children's Hospital, Department of Surgery, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Konstantin I. Maslov
- Optical Imaging Laboratory, Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Lihong V. Wang
- Optical Imaging Laboratory, Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA,Corresponding author. Tel.: +1 314 454 6022; fax: +1 314 454 2442. (L.V. Wang), (B.W. Warner)
| | - Brad W. Warner
- Division of Pediatric Surgery, St Louis Children's Hospital, Department of Surgery, Washington University School of Medicine, St Louis, MO 63110, USA,Corresponding author. Tel.: +1 314 454 6022; fax: +1 314 454 2442. (L.V. Wang), (B.W. Warner)
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9
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Rowland KJ, McMellen ME, Wakeman D, Wandu WS, Erwin CR, Warner BW. Enterocyte expression of epidermal growth factor receptor is not required for intestinal adaptation in response to massive small bowel resection. J Pediatr Surg 2012; 47:1748-53. [PMID: 22974617 PMCID: PMC3443391 DOI: 10.1016/j.jpedsurg.2012.03.089] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2012] [Accepted: 03/06/2012] [Indexed: 02/07/2023]
Abstract
PURPOSE Intestinal adaptation after massive small bowel resection (SBR) permits improved absorption of enteral nutrition despite significant loss of bowel length. Epidermal growth factor (EGF) and its receptor (EGFR) have previously been established to play major roles in the pathogenesis of adaptation. This study tested the hypothesis that EGFR signaling within the epithelial cell compartment (enterocytes) is required for intestinal adaptation. METHODS We developed a tamoxifen-inducible Villin-Cre/LoxP recombinant system for enterocyte-directed EGFR deletion using EGFR-floxed mice. Epidermal growth factor receptor-null mice and wild-type littermates underwent either 50% proximal SBR or sham operation. Ileal tissue was harvested on postoperative day 7. To assess for adaptation, villus height and crypt depth as well as rates of crypt cell proliferation and apoptosis were measured. RESULTS Adaptation after SBR occurred normally, as demonstrated by significant increases in villus height, crypt depth, and crypt proliferative and apoptotic index in both the wild-type and EGFR-null mice. CONCLUSION Enterocyte EGFR expression is not required for the adaptation response to massive SBR. This novel finding suggests that enterocyte proliferation during adaptation is regulated by EGFR signaling in cells other than enterocytes, perhaps within the mesenchymal cell compartment of the bowel wall via factor(s) that are presently unknown.
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Affiliation(s)
| | | | | | | | | | - Brad W. Warner
- Correspondence: Brad W. Warner, M.D., St. Louis Children's Hospital, One Children's Place; Suite 5S40, St. Louis MO 63110, (314) 454-6022 - Phone, (314) 454-2442 – Fax,
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Rowland KJ, Yao J, Wang L, Erwin CR, Maslov KI, Wang LV, Warner BW. Immediate alterations in intestinal oxygen saturation and blood flow after massive small bowel resection as measured by photoacoustic microscopy. J Pediatr Surg 2012; 47:1143-9. [PMID: 22703784 PMCID: PMC3377986 DOI: 10.1016/j.jpedsurg.2012.03.020] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2012] [Accepted: 03/05/2012] [Indexed: 10/28/2022]
Abstract
PURPOSE Massive small bowel resection (SBR) results in villus angiogenesis and a critical adaptation response within the remnant bowel. Previous ex vivo studies of intestinal blood flow after SBR are conflicting. We sought to determine the effect of SBR on intestinal hemodynamics using photoacoustic microscopy, a noninvasive, label-free, high-resolution in vivo hybrid imaging modality. METHODS Photoacoustic microscopy was used to image the intestine microvascular system and measure blood flow and oxygen saturation (So(2)) of the terminal mesenteric arteriole and accompanying vein in C57BL6 mice (n = 7) before and immediately after a 50% proximal SBR. A P value of less than .05 was considered significant. RESULTS Before SBR, arterial and venous So(2) were similar. Immediately after SBR, the venous So(2) decreased with an increase in the oxygen extraction fraction. In addition, the arterial and venous blood flow significantly decreased. CONCLUSION Massive SBR results in an immediate reduction in intestinal blood flow and increase in tissue oxygen utilization. These physiologic changes are observed throughout the remnant small intestine. The contribution of these early hemodynamic alterations may contribute to the induction of villus angiogenesis and the pathogenesis of normal intestinal adaptation responses.
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Affiliation(s)
- Kathryn J. Rowland
- Division of Pediatric Surgery, St Louis Children’s Hospital, Department of Surgery, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Junjie Yao
- Optical Imaging Laboratory, Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Lidai Wang
- Optical Imaging Laboratory, Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Christopher R. Erwin
- Division of Pediatric Surgery, St Louis Children’s Hospital, Department of Surgery, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Konstantin I. Maslov
- Optical Imaging Laboratory, Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Lihong V. Wang
- Optical Imaging Laboratory, Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA,Correspondence: L. V. Wang for photoacoustic imaging, . B. W. Warner for small bowel resection, , St. Louis Children’s Hospital, One Children’s Place; Suite 5S40, St. Louis MO 63110, (314) 454-6022 – Phone, (314) 454-2442 – Fax
| | - Brad W. Warner
- Division of Pediatric Surgery, St Louis Children’s Hospital, Department of Surgery, Washington University School of Medicine, St Louis, MO 63110, USA,Correspondence: L. V. Wang for photoacoustic imaging, . B. W. Warner for small bowel resection, , St. Louis Children’s Hospital, One Children’s Place; Suite 5S40, St. Louis MO 63110, (314) 454-6022 – Phone, (314) 454-2442 – Fax
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Hitch MC, Leinicke JA, Wakeman D, Guo J, Erwin CR, Rowland KJ, Merrick EC, Heuckeroth RO, Warner BW. Ret heterozygous mice have enhanced intestinal adaptation after massive small bowel resection. Am J Physiol Gastrointest Liver Physiol 2012; 302:G1143-50. [PMID: 22421622 PMCID: PMC3362098 DOI: 10.1152/ajpgi.00296.2011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Intestinal adaptation is an important compensatory response to massive small bowel resection (SBR) and occurs because of a proliferative stimulus to crypt enterocytes by poorly understood mechanisms. Recent studies suggest the enteric nervous system (ENS) influences enterocyte proliferation. We, therefore, sought to determine whether ENS dysfunction alters resection-induced adaptation responses. Ret+/- mice with abnormal ENS function and wild-type (WT) littermates underwent sham surgery or 50% SBR. After 7 days, ileal morphology, enterocyte proliferation, apoptosis, and selected signaling proteins were characterized. Crypt depth and villus height were equivalent at baseline in WT and Ret+/- mice. In contrast after SBR, Ret+/- mice had longer villi (Ret+/- 426.7 ± 46.0 μm vs. WT 306.5 ± 7.7 μm, P < 0.001) and deeper crypts (Ret+/- 119 ± 3.4 μm vs. WT 82.4 ± 3.1 μm, P < 0.001) than WT. Crypt enterocyte proliferation was higher in Ret+/- (48.8 ± 1.3%) than WT (39.9 ± 2.1%; P < 0.001) after resection, but apoptosis rates were similar. Remnant bowel of Ret+/- mice also had higher levels of glucagon-like peptide 2 (6.2-fold, P = 0.005) and amphiregulin (4.6-fold, P < 0.001) mRNA after SBR, but serum glucagon-like peptide 2 protein levels were equal in WT and Ret+/- mice, and there was no evidence of increased c-Fos nuclear localization in submucosal neurons. Western blot confirmed higher crypt epidermal growth factor receptor (EGFR) protein levels (1.44-fold; P < 0.001) and more phosphorylated EGFR (2-fold; P = 0.003) in Ret+/- than WT mice after SBR. These data suggest that Ret heterozygosity enhances intestinal adaptation after massive SBR, likely via enhanced EGFR signaling. Reducing Ret activity or altering ENS function may provide a novel strategy to enhance adaptation attenuating morbidity in patients with short bowel syndrome.
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Affiliation(s)
- Meredith C. Hitch
- 1Department of Pediatrics, Division of Pediatric Gastroenterology, Hepatology, and Nutrition, and
| | - Jennifer A. Leinicke
- 2Department of Surgery, Division of Pediatric Surgery, Washington University School of Medicine, St. Louis Children's Hospital, and
| | - Derek Wakeman
- 2Department of Surgery, Division of Pediatric Surgery, Washington University School of Medicine, St. Louis Children's Hospital, and
| | - Jun Guo
- 2Department of Surgery, Division of Pediatric Surgery, Washington University School of Medicine, St. Louis Children's Hospital, and
| | - Chris R. Erwin
- 2Department of Surgery, Division of Pediatric Surgery, Washington University School of Medicine, St. Louis Children's Hospital, and
| | - Kathryn J. Rowland
- 2Department of Surgery, Division of Pediatric Surgery, Washington University School of Medicine, St. Louis Children's Hospital, and
| | - Ellen C. Merrick
- 1Department of Pediatrics, Division of Pediatric Gastroenterology, Hepatology, and Nutrition, and
| | - Robert O. Heuckeroth
- 1Department of Pediatrics, Division of Pediatric Gastroenterology, Hepatology, and Nutrition, and ,3Department of Developmental, Regenerative and Stem Cell Biology, Washington University School of Medicine, St. Louis, Missouri
| | - Brad W. Warner
- 2Department of Surgery, Division of Pediatric Surgery, Washington University School of Medicine, St. Louis Children's Hospital, and
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Chen J, Wen J, Cai W. Smooth muscle adaptation and recovery of contractility after massive small bowel resection in rats. Exp Biol Med (Maywood) 2012; 237:578-84. [PMID: 22581812 DOI: 10.1258/ebm.2012.011338] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Previous studies have suggested that massive small bowel resection (mSBR) compromises the normal intestinal processes of digestion and absorption, and requires an adaptive response to regain full function and reinstate coordinated contractile activity of the circular smooth muscle. This study was designed to investigate spontaneous contractile activity of circular smooth muscle using the mSBR rat model and to determine the functional role of M(2) and M(3) muscarinic acetylcholine receptors (mAChR) in this process. Male Sprague-Dawley rats underwent an 80% proximal SBR or sham operation. Markers of adaptation, including villus and microvillus height, were analyzed by hematoxylin and eosin staining and transmission electron microscopy. Contractility was measured by attaching the distal ileum strips to strain gauge transducers and exposing the tissue to varying doses of the cholinergic agonist carbachol. Protein expressions of M(2)- and M(3)-mAChR in intestinal smooth muscle (ISM) were detected by Western blot. Following mSBR, the ISM showed perturbed spontaneous rhythmic contraction, irregular amplitude and slow frequency by muscle strip test. However, by two weeks after mSBR, the contractile function of circular smooth muscle was found to have returned to normal levels. Protein expression of M(2)-mAChR was down-regulated following mSBR but up-regulated during the adaptive process when contractile activity of circular smooth muscle was regained. These results indicate that smooth muscle contractility was spontaneously restored in rats following mSBR, and involved the acetylcholine receptors M(2) and M(3). Thus, the disrupted contractile response of smooth muscle in short bowel syndrome may be corrected by therapeutic intervention to restore the expressions of M(2)- and M(3)-mAChR to pre-mSBR levels.
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Affiliation(s)
- Jie Chen
- Department of Pediatric Surgery, School of Medicine, Xin Hua Hospital, Shanghai Institute of Pediatric Research, Shanghai Jiao Tong University, 1665 Kong Jiang Road 200092, Shanghai, China
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Martin CA, Perrone EE, Longshore SW, Toste P, Kathryn MD, Nair R, Guo J, Erwin CR, Warner BW. Intestinal resection induces angiogenesis within adapting intestinal villi. J Pediatr Surg 2009; 44:1077-82; discussion 1083. [PMID: 19524720 PMCID: PMC2697129 DOI: 10.1016/j.jpedsurg.2009.02.036] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2009] [Accepted: 02/17/2009] [Indexed: 12/13/2022]
Abstract
PURPOSE Adaptive growth of the intestinal mucosa in response to massive gut loss is fundamental for autonomy from parenteral nutrition. Although angiogenesis is essential for cellular proliferation in other tissues, its relevance to intestinal adaptation is unknown. We tested the hypothesis that resection-induced adaptation is associated with new blood vessel growth. METHODS Male C57Bl/6 mice underwent either a 50% small bowel resection or a sham (transection and reanastomosis) operation. After 1, 3, or 7 days, capillary density within the intestinal villi was measured using confocal microscopy. A messenger RNA reverse-transcriptase polymerase chain reaction (RT-PCR) array was used to determine angiogenic gene expression during adaptation. RESULTS Mice that underwent small bowel resection had a significantly increased capillary density compared to sham-operated mice at postoperative day 7. This morphological alteration was preceded by significant alterations in 5 candidate genes at postoperative day 3. CONCLUSION New vessel blood growth is observed in the adapting intestine after massive small bowel loss. This response appears to follow rather than initiate the adaptive alterations in mucosal morphology that are characteristic of adaptation. A better understanding of this progress and the signaling factors involved may improve therapeutic options for children with short gut syndrome.
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Affiliation(s)
- Colin A. Martin
- Division of Pediatric General and Thoracic Surgery, Cincinnati Children’s Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, OH
| | - Erin E. Perrone
- Division of Pediatric Surgery, St. Louis Children’s Hospital, Washington University School of Medicine, St. Louis, MO
- Department of Surgery, Wayne State University School of Medicine, Detroit, MI
| | - Shannon W. Longshore
- Division of Pediatric Surgery, St. Louis Children’s Hospital, Washington University School of Medicine, St. Louis, MO
- Department of Surgery, University of California, Davis Medical Center, Sacramento, CA
| | - Paul Toste
- Division of Pediatric General and Thoracic Surgery, Cincinnati Children’s Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, OH
| | - MD Kathryn
- Division of Pediatric Surgery, St. Louis Children’s Hospital, Washington University School of Medicine, St. Louis, MO
| | - Rajalakshmi Nair
- Division of Pediatric General and Thoracic Surgery, Cincinnati Children’s Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, OH
- Division of Pediatric Surgery, St. Louis Children’s Hospital, Washington University School of Medicine, St. Louis, MO
| | - Jun Guo
- Division of Pediatric Surgery, St. Louis Children’s Hospital, Washington University School of Medicine, St. Louis, MO
| | - Christopher R. Erwin
- Division of Pediatric Surgery, St. Louis Children’s Hospital, Washington University School of Medicine, St. Louis, MO
| | - Brad W. Warner
- Division of Pediatric Surgery, St. Louis Children’s Hospital, Washington University School of Medicine, St. Louis, MO
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Abstract
Colon cancer accounts for more than 10% of all cancer deaths annually. Our genetic evidence from Drosophila and previous in vitro studies of mammalian Atonal homolog 1 (Atoh1, also called Math1 or Hath1) suggest an anti-oncogenic function for the Atonal group of proneural basic helix-loop-helix transcription factors. We asked whether mouse Atoh1 and human ATOH1 act as tumor suppressor genes in vivo. Genetic knockouts in mouse and molecular analyses in the mouse and in human cancer cell lines support a tumor suppressor function for ATOH1. ATOH1 antagonizes tumor formation and growth by regulating proliferation and apoptosis, likely via activation of the Jun N-terminal kinase signaling pathway. Furthermore, colorectal cancer and Merkel cell carcinoma patients show genetic and epigenetic ATOH1 loss-of-function mutations. Our data indicate that ATOH1 may be an early target for oncogenic mutations in tissues where it instructs cellular differentiation.
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Guo J, Longshore S, Nair R, Warner BW. Retinoblastoma protein (pRb), but not p107 or p130, is required for maintenance of enterocyte quiescence and differentiation in small intestine. J Biol Chem 2008; 284:134-140. [PMID: 18981186 DOI: 10.1074/jbc.m806133200] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The function of retinoblastoma protein (pRb) in the regulation of small intestine epithelial cell homeostasis has been challenged by several groups using various promoter-based Cre transgenic mouse lines. Interestingly, different pRb deletion systems yield dramatically disparate small intestinal phenotypes. These findings confound the function of pRb in this dynamic tissue. In this study, Villin-Cre transgenic mice were crossed with Rb (flox/flox) mice to conditionally delete pRb protein in small intestine enterocytes. We discovered a novel hyperplasia phenotype as well as ectopic cell cycle reentry within villus enterocytes in the small intestine. This phenotype was not seen in other pRb family member (p107 or p130) null mice. Using a newly developed crypt/villus isolation method, we uncovered that expression of pRb was undetectable, whereas proliferating cell nuclear antigen, p107, cyclin E, cyclin D3, Cdk2, and Cdc2 were dramatically increased in pRb-deficient villus cells. Cyclin A, cyclin D1, cyclin D2, and Cdk4/6 expression was not affected by absent pRb expression. pRb-deficient villus cells appeared capable of progressing to mitosis but with higher rates of apoptosis. However, the cycling villus enterocytes were not completely differentiated as gauged by significant reduction of intestinal fatty acid-binding protein expression. In summary, pRb, but not p107 or p130, is required for maintaining the postmitotic villus cell in quiescence, governing the expression of cell cycle regulatory proteins, and completing of absorptive enterocyte differentiation in the small intestine.
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Affiliation(s)
- Jun Guo
- Division of Pediatric Surgery, Washington University School of Medicine, St. Louis Children's Hospital, St. Louis, Missouri 63110
| | - Shannon Longshore
- Division of Pediatric Surgery, Washington University School of Medicine, St. Louis Children's Hospital, St. Louis, Missouri 63110
| | - Rajalakshmi Nair
- Division of Pediatric Surgery, Washington University School of Medicine, St. Louis Children's Hospital, St. Louis, Missouri 63110
| | - Brad W Warner
- Division of Pediatric Surgery, Washington University School of Medicine, St. Louis Children's Hospital, St. Louis, Missouri 63110.
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