101
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Dempsey PJ. Role of ADAM10 in intestinal crypt homeostasis and tumorigenesis. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2017; 1864:2228-2239. [PMID: 28739265 PMCID: PMC5632589 DOI: 10.1016/j.bbamcr.2017.07.011] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2017] [Revised: 07/19/2017] [Accepted: 07/20/2017] [Indexed: 12/17/2022]
Abstract
A disintegrin and metalloproteinases (ADAMs) are a family of mSultidomain, membrane-anchored proteases that regulate diverse cellular functions, including cell adhesion, migration, proteolysis and other cell signaling events. Catalytically-active ADAMs act as ectodomain sheddases that proteolytically cleave type I and type II transmembrane proteins and some GPI-anchored proteins from the cellular surface. ADAMs can also modulate other cellular signaling events through a process known as regulated intramembrane proteolysis (RIP). Through their proteolytic activity, ADAMs can rapidly modulate key cell signaling pathways in response to changes in the extracellular environment (e.g. inflammation) and play a central role in coordinating intercellular communication. Dysregulation of these processes through aberrant expression, or sustained ADAM activity, is linked to chronic inflammation, inflammation-associated cancer and tumorigenesis. ADAM10 was the first disintegrin-metalloproteinase demonstrated to have proteolytic activity and is the prototypic ADAM associated with RIP activity (e.g. sequential Notch receptor processing). ADAM10 is abundantly expressed throughout the gastrointestinal tract and during normal intestinal homeostasis ADAM10 regulates many cellular processes associated with intestinal development, cell fate specification and maintenance of intestinal stem cell/progenitor populations. In addition, several signaling pathways that undergo ectodomain shedding by ADAM10 (e.g. Notch, EGFR/ErbB, IL-6/sIL-6R) help control intestinal injury/regenerative responses and may drive intestinal inflammation and colon cancer initiation and progression. Here, I review some of the proposed functions of ADAM10 associated with intestinal crypt homeostasis and tumorigenesis within the gastrointestinal tract in vivo. This article is part of a Special Issue entitled: Proteolysis as a Regulatory Event in Pathophysiology edited by Stefan Rose-John.
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Affiliation(s)
- Peter J Dempsey
- Graduate Program in Cell Biology, Stem Cells, and Development Program, University of Colorado Medical School, Aurora, CO 80045, United States; Division of Gastroenterology, Hepatology and Nutrition, Department of Pediatrics, University of Colorado Medical School, Aurora, CO 80045, United States.
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102
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Goichberg P. Current Understanding of the Pathways Involved in Adult Stem and Progenitor Cell Migration for Tissue Homeostasis and Repair. Stem Cell Rev Rep 2017; 12:421-37. [PMID: 27209167 DOI: 10.1007/s12015-016-9663-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
With the advancements in the field of adult stem and progenitor cells grows the recognition that the motility of primitive cells is a pivotal aspect of their functionality. There is accumulating evidence that the recruitment of tissue-resident and circulating cells is critical for organ homeostasis and effective injury responses, whereas the pathobiology of degenerative diseases, neoplasm and aging, might be rooted in the altered ability of immature cells to migrate. Furthermore, understanding the biological machinery determining the translocation patterns of tissue progenitors is of great relevance for the emerging methodologies for cell-based therapies and regenerative medicine. The present article provides an overview of studies addressing the physiological significance and diverse modes of stem and progenitor cell trafficking in adult mammalian organs, discusses the major microenvironmental cues regulating cell migration, and describes the implementation of live imaging approaches for the exploration of stem cell movement in tissues and the factors dictating the motility of endogenous and transplanted cells with regenerative potential.
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Affiliation(s)
- Polina Goichberg
- Department Anesthesiology, Perioperative and Pain Medicine, Harvard Medical School, Brigham and Women's Hospital, 75 Francis Street, Boston, MA, 02115, USA.
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103
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Thalheim T, Buske P, Przybilla J, Rother K, Loeffler M, Galle J. Stem cell competition in the gut: insights from multi-scale computational modelling. J R Soc Interface 2017; 13:rsif.2016.0218. [PMID: 27534699 PMCID: PMC5014057 DOI: 10.1098/rsif.2016.0218] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Accepted: 07/21/2016] [Indexed: 12/14/2022] Open
Abstract
Three-dimensional (3D) computational tissue models can provide a comprehensive description of tissue dynamics at the molecular, cellular and tissue level. Moreover, they can support the development of hypotheses about cellular interactions and about synergies between major signalling pathways. We exemplify these capabilities by simulation of a 3D single-cell-based model of mouse small intestinal crypts. We analyse the impact of lineage specification, distribution and cellular lifespan on clonal competition and study effects of Notch- and Wnt activation on fixation of mutations within the tissue. Based on these results, we predict that experimentally observed synergistic effects between autonomous Notch- and Wnt signalling in triggering intestinal tumourigenesis originate in the suppression of Wnt-dependent secretory lineage specification by Notch, giving rise to an increased fixation probability of Wnt-activating mutations. Our study demonstrates that 3D computational tissue models can support a mechanistic understanding of long-term tissue dynamics under homeostasis and during transformation.
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Affiliation(s)
- Torsten Thalheim
- Interdisciplinary Center for Bioinformatics, Leipzig University, Haertelstr. 16-18, 04107 Leipzig, Germany
| | - Peter Buske
- Interdisciplinary Center for Bioinformatics, Leipzig University, Haertelstr. 16-18, 04107 Leipzig, Germany
| | - Jens Przybilla
- Interdisciplinary Center for Bioinformatics, Leipzig University, Haertelstr. 16-18, 04107 Leipzig, Germany
| | - Karen Rother
- Interdisciplinary Center for Bioinformatics, Leipzig University, Haertelstr. 16-18, 04107 Leipzig, Germany
| | - Markus Loeffler
- Interdisciplinary Center for Bioinformatics, Leipzig University, Haertelstr. 16-18, 04107 Leipzig, Germany Institute for Medical Informatics, Statistics and Epidemiology, Leipzig University, Haertelstr. 16-18, 04107 Leipzig, Germany
| | - Joerg Galle
- Interdisciplinary Center for Bioinformatics, Leipzig University, Haertelstr. 16-18, 04107 Leipzig, Germany
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104
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Kim CK, Yang VW, Bialkowska AB. The Role of Intestinal Stem Cells in Epithelial Regeneration Following Radiation-Induced Gut Injury. CURRENT STEM CELL REPORTS 2017; 3:320-332. [PMID: 29497599 PMCID: PMC5818549 DOI: 10.1007/s40778-017-0103-7] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Purpose of Review Intestinal epithelial cells show remarkable plasticity in regenerating the epithelium following radiation injury. In this review, we explore the regenerative capacity and mechanisms of various populations of intestinal stem cells (ISCs) in response to ionizing radiation. Recent Findings Ionizing radiation targets mitotic cells that include “active” ISCs and progenitor cells. Lineage-tracing experiments showed that several different cell types identified by a single or combination of markers are capable of regenerating the epithelium, confirming that ISCs exhibit a high degree of plasticity. However, the identities of the contributing cells marked by various markers require further validation. Summary Following radiation injury, quiescent and/or radioresistant cells become active stem cells to regenerate the epithelium. Looking forward, understanding the mechanisms by which ISCs govern tissue regeneration is crucial to determine therapeutic approaches to promote intestinal epithelial regeneration following injury.
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Affiliation(s)
- Chang-Kyung Kim
- 1Department of Medicine, Stony Brook University School of Medicine, HSC T-17, Rm. 090, Stony Brook, NY 11794 USA
| | - Vincent W Yang
- 1Department of Medicine, Stony Brook University School of Medicine, HSC T-17, Rm. 090, Stony Brook, NY 11794 USA.,2Department of Physiology and Biophysics, Stony Brook University School of Medicine, Stony Brook, NY 11794 USA
| | - Agnieszka B Bialkowska
- 1Department of Medicine, Stony Brook University School of Medicine, HSC T-17, Rm. 090, Stony Brook, NY 11794 USA
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105
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Hippo signalling in intestinal regeneration and cancer. Curr Opin Cell Biol 2017; 48:17-25. [DOI: 10.1016/j.ceb.2017.04.005] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 04/25/2017] [Accepted: 04/27/2017] [Indexed: 12/19/2022]
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106
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Siebel C, Lendahl U. Notch Signaling in Development, Tissue Homeostasis, and Disease. Physiol Rev 2017; 97:1235-1294. [PMID: 28794168 DOI: 10.1152/physrev.00005.2017] [Citation(s) in RCA: 598] [Impact Index Per Article: 85.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Revised: 05/19/2017] [Accepted: 05/26/2017] [Indexed: 02/07/2023] Open
Abstract
Notch signaling is an evolutionarily highly conserved signaling mechanism, but in contrast to signaling pathways such as Wnt, Sonic Hedgehog, and BMP/TGF-β, Notch signaling occurs via cell-cell communication, where transmembrane ligands on one cell activate transmembrane receptors on a juxtaposed cell. Originally discovered through mutations in Drosophila more than 100 yr ago, and with the first Notch gene cloned more than 30 yr ago, we are still gaining new insights into the broad effects of Notch signaling in organisms across the metazoan spectrum and its requirement for normal development of most organs in the body. In this review, we provide an overview of the Notch signaling mechanism at the molecular level and discuss how the pathway, which is architecturally quite simple, is able to engage in the control of cell fates in a broad variety of cell types. We discuss the current understanding of how Notch signaling can become derailed, either by direct mutations or by aberrant regulation, and the expanding spectrum of diseases and cancers that is a consequence of Notch dysregulation. Finally, we explore the emerging field of Notch in the control of tissue homeostasis, with examples from skin, liver, lung, intestine, and the vasculature.
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Affiliation(s)
- Chris Siebel
- Department of Discovery Oncology, Genentech Inc., DNA Way, South San Francisco, California; and Department of Cell and Molecular Biology, Karolinska Institute, Stockholm, Sweden
| | - Urban Lendahl
- Department of Discovery Oncology, Genentech Inc., DNA Way, South San Francisco, California; and Department of Cell and Molecular Biology, Karolinska Institute, Stockholm, Sweden
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107
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Smith RJ, Rao-Bhatia A, Kim TH. Signaling and epigenetic mechanisms of intestinal stem cells and progenitors: insight into crypt homeostasis, plasticity, and niches. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2017. [PMID: 28644919 DOI: 10.1002/wdev.281] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The rapid turnover of intestinal epithelial cells is maintained by a small number of stem cells located in pocket-like gland structures called crypts. While our understanding of the identity and function of intestinal stem cells (ISCs) has rapidly progressed, epigenetic and transcriptional regulation in crypt stem cell and progenitor pools remains an active field of investigation. Surrounded by various types of cells in the stroma, crypt progenitors display high levels of plasticity, harboring the ability to interconvert in the face of epithelial damage. Recent studies analyzing epigenetic patterns of intestinal epithelial cells have provided evidence that plasticity is maintained by a broadly permissive epigenomic state, wherein cell-lineage specification is directed through activation of signaling pathways and transcription factor (TF) expression. New studies also have shown that the ISC niche, which is comprised of surrounding epithelial and mesenchymal tissues, plays a crucial role in supporting the maintenance and differentiation of stem cells by providing contextual information in the form of signaling cascades, such as Wnt, Notch, and Hippo. These cascades ultimately govern TF expression to promote early cell-lineage decisions in both crypt stem cells and progenitors. Highlighting recent studies investigating signaling, transcriptional, and epigenetic mechanisms of intestinal epithelial cells, we will discuss the mechanisms underlying crypt homeostasis, plasticity, and niches. WIREs Dev Biol 2017, 6:e281. doi: 10.1002/wdev.281 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Ryan J Smith
- Program of Developmental and Stem Cell Biology, The Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Abilasha Rao-Bhatia
- Program of Developmental and Stem Cell Biology, The Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Tae-Hee Kim
- Program of Developmental and Stem Cell Biology, The Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
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108
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Kishida K, Pearce SC, Yu S, Gao N, Ferraris RP. Nutrient sensing by absorptive and secretory progenies of small intestinal stem cells. Am J Physiol Gastrointest Liver Physiol 2017; 312:G592-G605. [PMID: 28336548 PMCID: PMC5495913 DOI: 10.1152/ajpgi.00416.2016] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 03/15/2017] [Accepted: 03/16/2017] [Indexed: 01/31/2023]
Abstract
Nutrient sensing triggers responses by the gut-brain axis modulating hormone release, feeding behavior and metabolism that become dysregulated in metabolic syndrome and some cancers. Except for absorptive enterocytes and secretory enteroendocrine cells, the ability of many intestinal cell types to sense nutrients is still unknown; hence we hypothesized that progenitor stem cells (intestinal stem cells, ISC) possess nutrient sensing ability inherited by progenies during differentiation. We directed via modulators of Wnt and Notch signaling differentiation of precursor mouse intestinal crypts into specialized organoids each containing ISC, enterocyte, goblet, or Paneth cells at relative proportions much higher than in situ as determined by mRNA expression and immunocytochemistry of cell type biomarkers. We identified nutrient sensing cell type(s) by increased expression of fructolytic genes in response to a fructose challenge. Organoids comprised primarily of enterocytes, Paneth, or goblet, but not ISC, cells responded specifically to fructose without affecting nonfructolytic genes. Sensing was independent of Wnt and Notch modulators and of glucose concentrations in the medium but required fructose absorption and metabolism. More mature enterocyte- and goblet-enriched organoids exhibited stronger fructose responses. Remarkably, enterocyte organoids, upon forced dedifferentiation to reacquire ISC characteristics, exhibited a markedly extended lifespan and retained fructose sensing ability, mimicking responses of some dedifferentiated cancer cells. Using an innovative approach, we discovered that nutrient sensing is likely repressed in progenitor ISCs then irreversibly derepressed during specification into sensing-competent absorptive or secretory lineages, the surprising capacity of Paneth and goblet cells to detect fructose, and the important role of differentiation in modulating nutrient sensing.NEW & NOTEWORTHY Small intestinal stem cells differentiate into several cell types transiently populating the villi. We used specialized organoid cultures each comprised of a single cell type to demonstrate that 1) differentiation seems required for nutrient sensing, 2) secretory goblet and Paneth cells along with enterocytes sense fructose, suggesting that sensing is acquired after differentiation is triggered but before divergence between absorptive and secretory lineages, and 3) forcibly dedifferentiated enterocytes exhibit fructose sensing and lifespan extension.
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Affiliation(s)
- Kunihiro Kishida
- 1Department of Pharmacology, Physiology and Neurosciences, New Jersey Medical School, Rutgers University, Newark, New Jersey; and
| | - Sarah C. Pearce
- 1Department of Pharmacology, Physiology and Neurosciences, New Jersey Medical School, Rutgers University, Newark, New Jersey; and
| | - Shiyan Yu
- 2Department of Biological Sciences, Life Science Center, Rutgers University, Newark, New Jersey
| | - Nan Gao
- 2Department of Biological Sciences, Life Science Center, Rutgers University, Newark, New Jersey
| | - Ronaldo P. Ferraris
- 1Department of Pharmacology, Physiology and Neurosciences, New Jersey Medical School, Rutgers University, Newark, New Jersey; and
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109
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Wang P, Shu B, Xu Y, Zhu J, Liu J, Zhou Z, Chen L, Zhao J, Liu X, Qi S, Xiong K, Xie J. Basic fibroblast growth factor reduces scar by inhibiting the differentiation of epidermal stem cells to myofibroblasts via the Notch1/Jagged1 pathway. Stem Cell Res Ther 2017; 8:114. [PMID: 28511663 PMCID: PMC5434520 DOI: 10.1186/s13287-017-0549-7] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Revised: 02/28/2017] [Accepted: 03/31/2017] [Indexed: 01/08/2023] Open
Abstract
Background Basic fibroblast growth factor (bFGF) plays an important role in promoting wound healing and reducing scar, but the possible molecular mechanisms are still unclear. Our previous studies have found that activating the Notch1/Jagged1 pathway can inhibit the differentiation of epidermal stem cells (ESCs) to myofibroblasts (MFB). Herein, we document that bFGF reduces scar by inhibiting the differentiation of ESCs to MFB via activating the Notch1/Jagged1 pathway. Methods In in-vitro study, ESCs were isolated from 10 neonatal SD rats (1–3 days old), cultured in keratinocyte serum-free medium, and divided into six groups: bFGF group, bFGF + SU5402 group, bFGF + DAPT group, siJagged1 group, bFGF + siJagged1 group, and control group. Jagged1 of the ESCs in the siJagged1 group and bFGF + siJagged1 group was knocked down by small-interfering RNA transfection. Expression of ESC markers (CK15/CK10), MFB markers (α-SMA, Collagen I, Collagen III), and Notch1/Jagged1 components (Jagged1, Notch1, Hes1) was detected by FCM, qRT-PCR, and western blot analysis to study the relationships of bFGF, ESCs, and Notch1/Jagged1 pathway. In in-vivo study, the wound healing time and scar hyperplasia were observed on rabbit ear scar models. The quality of wound healing was estimated by hematoxylin and eosin staining and Masson staining. Expression of ESC markers, MFB markers and Notch1/Jagged1 components was elucidated by immunohistochemistry, immunofluorescence, and western blot analysis. Results The in-vitro study showed that bFGF could significantly upregulate the expression of ESC markers and Notch1/Jagged1 components, while downregulating the expression of MFB markers at the same time. However, these effects could be obviously decreased when we knocked down Jagged1 or added DAPT. Similarly, in in-vivo study, bFGF also exhibited its functions in inhibiting the differentiation of rabbit ESCs to MFB by activating the Notch1/Jagged1 pathway, which improved the wound healing quality and alleviated scar significantly. Conclusion These results provide evidence that bFGF can reduce scar by inhibiting the differentiation of ESCs to MFB via the Notch1/Jagged1 pathway, and present a new promising potential direction for the treatment of scar.
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Affiliation(s)
- Peng Wang
- Department of Burn Surgery, First Affiliated Hospital of Sun Yat-Sen University, No. 58, 2nd Zhongshan Road, Yuexiu District, Guangzhou, Guangdong Province, 510080, People's Republic of China
| | - Bin Shu
- Department of Burn Surgery, First Affiliated Hospital of Sun Yat-Sen University, No. 58, 2nd Zhongshan Road, Yuexiu District, Guangzhou, Guangdong Province, 510080, People's Republic of China
| | - Yingbin Xu
- Department of Burn Surgery, First Affiliated Hospital of Sun Yat-Sen University, No. 58, 2nd Zhongshan Road, Yuexiu District, Guangzhou, Guangdong Province, 510080, People's Republic of China
| | - Jiayuan Zhu
- Department of Burn Surgery, First Affiliated Hospital of Sun Yat-Sen University, No. 58, 2nd Zhongshan Road, Yuexiu District, Guangzhou, Guangdong Province, 510080, People's Republic of China
| | - Jian Liu
- Department of Burn Surgery, First Affiliated Hospital of Sun Yat-Sen University, No. 58, 2nd Zhongshan Road, Yuexiu District, Guangzhou, Guangdong Province, 510080, People's Republic of China
| | - Ziheng Zhou
- Department of Burn Surgery, First Affiliated Hospital of Sun Yat-Sen University, No. 58, 2nd Zhongshan Road, Yuexiu District, Guangzhou, Guangdong Province, 510080, People's Republic of China
| | - Lei Chen
- Department of Burn Surgery, First Affiliated Hospital of Sun Yat-Sen University, No. 58, 2nd Zhongshan Road, Yuexiu District, Guangzhou, Guangdong Province, 510080, People's Republic of China
| | - Jingling Zhao
- Department of Burn Surgery, First Affiliated Hospital of Sun Yat-Sen University, No. 58, 2nd Zhongshan Road, Yuexiu District, Guangzhou, Guangdong Province, 510080, People's Republic of China
| | - Xusheng Liu
- Department of Burn Surgery, First Affiliated Hospital of Sun Yat-Sen University, No. 58, 2nd Zhongshan Road, Yuexiu District, Guangzhou, Guangdong Province, 510080, People's Republic of China
| | - Shaohai Qi
- Department of Burn Surgery, First Affiliated Hospital of Sun Yat-Sen University, No. 58, 2nd Zhongshan Road, Yuexiu District, Guangzhou, Guangdong Province, 510080, People's Republic of China
| | - Kun Xiong
- Department of Anatomy and Neurobiology, School of Basic Medical Sciences, Central South University, Changsha, Hunan Province, 410013, People's Republic of China
| | - Julin Xie
- Department of Burn Surgery, First Affiliated Hospital of Sun Yat-Sen University, No. 58, 2nd Zhongshan Road, Yuexiu District, Guangzhou, Guangdong Province, 510080, People's Republic of China.
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Effect of essential amino acids on enteroids: Methionine deprivation suppresses proliferation and affects differentiation in enteroid stem cells. Biochem Biophys Res Commun 2017; 488:171-176. [PMID: 28483523 DOI: 10.1016/j.bbrc.2017.05.029] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Accepted: 05/04/2017] [Indexed: 11/22/2022]
Abstract
We investigated the effects of essential amino acids on intestinal stem cell proliferation and differentiation using murine small intestinal organoids (enteroids) from the jejunum. By selectively removing individual essential amino acids from culture medium, we found that 24 h of methionine (Met) deprivation markedly suppressed cell proliferation in enteroids. This effect was rescued when enteroids cultured in Met deprivation media for 12 h were transferred to complete medium, suggesting that Met plays an important role in enteroid cell proliferation. In addition, mRNA levels of the stem cell marker leucine-rich repeat-containing G protein-coupled receptor 5 (Lgr5) decreased in enteroids grown in Met deprivation conditions. Consistent with this observation, Met deprivation also attenuated Lgr5-EGFP fluorescence intensity in enteroids. In contrast, Met deprivation enhanced mRNA levels of the enteroendocrine cell marker chromogranin A (ChgA) and markers of K cells, enterochromaffin cells, goblet cells, and Paneth cells. Immunofluorescence experiments demonstrated that Met deprivation led to an increase in the number of ChgA-positive cells. These results suggest that Met deprivation suppresses stem cell proliferation, thereby promoting differentiation. In conclusion, Met is an important nutrient in the maintenance of intestinal stem cells and Met deprivation potentially affects cell differentiation.
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111
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Corson F, Couturier L, Rouault H, Mazouni K, Schweisguth F. Self-organized Notch dynamics generate stereotyped sensory organ patterns in Drosophila. Science 2017; 356:science.aai7407. [PMID: 28386027 DOI: 10.1126/science.aai7407] [Citation(s) in RCA: 85] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2016] [Accepted: 03/20/2017] [Indexed: 12/26/2022]
Abstract
The emergence of spatial patterns in developing multicellular organisms relies on positional cues and cell-cell communication. Drosophila sensory organs have informed a paradigm in which these operate in two distinct steps: Prepattern factors drive localized proneural activity, then Notch-mediated lateral inhibition singles out neural precursors. Here we show that self-organization through Notch signaling also establishes the proneural stripes that resolve into rows of sensory bristles on the fly thorax. Patterning, initiated by a gradient of Delta ligand expression, progresses through inhibitory signaling between and within stripes. Thus, Notch signaling can support self-organized tissue patterning as a prepattern is transduced by cell-cell interactions into a refined arrangement of cellular fates.
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Affiliation(s)
- Francis Corson
- Laboratoire de Physique Statistique, Ecole Normale Supérieure, CNRS, Université Pierre et Marie Curie, Université Paris Diderot, 75005 Paris, France.
| | - Lydie Couturier
- Department of Developmental and Stem Cell Biology, Institut Pasteur, 75015 Paris, France.,CNRS, UMR3738, 75015 Paris, France
| | - Hervé Rouault
- Department of Developmental and Stem Cell Biology, Institut Pasteur, 75015 Paris, France.,CNRS, UMR3738, 75015 Paris, France
| | - Khalil Mazouni
- Department of Developmental and Stem Cell Biology, Institut Pasteur, 75015 Paris, France.,CNRS, UMR3738, 75015 Paris, France
| | - François Schweisguth
- Department of Developmental and Stem Cell Biology, Institut Pasteur, 75015 Paris, France. .,CNRS, UMR3738, 75015 Paris, France
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112
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Sugiyama M, Oki E, Nakaji Y, Tsutsumi S, Ono N, Nakanishi R, Sugiyama M, Nakashima Y, Sonoda H, Ohgaki K, Yamashita N, Saeki H, Okano S, Kitao H, Morita M, Oda Y, Maehara Y. High expression of the Notch ligand Jagged-1 is associated with poor prognosis after surgery for colorectal cancer. Cancer Sci 2017; 107:1705-1716. [PMID: 27589478 PMCID: PMC5132269 DOI: 10.1111/cas.13075] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Revised: 08/21/2016] [Accepted: 08/28/2016] [Indexed: 12/20/2022] Open
Abstract
The importance of Notch signaling in colorectal cancer (CRC) carcinogenesis and progression has previously been presented. Increased expression of Jagged‐1 (JAG1), a Notch ligand, in CRC has been revealed, but the detailed prognostic significance of JAG1 in CRC has not been determined. Protein expression of JAG1 was examined using immunohistochemistry in 158 CRC specimens. Expression of JAG1 and E‐cadherin and their associations with clinicopathologic characteristics, overall survival (OS) and relapse‐free survival (RFS) were evaluated. In vitro studies using compounds to regulate intracellular signaling and small interfering RNA to silence JAG1 were performed in a colon cancer cell line. JAG1 expression in cancerous tissues was weak, moderate or strong in 32%, 36% and 32% of specimens, respectively, and correlated with histologic type and T stage. In multivariate analysis, JAG1 expression, histologic type and lymphatic invasion independently correlated with OS and RFS. The combination of high JAG1 expression and low E‐cadherin expression had an additive effect toward poorer OS and RFS compared with the low JAG1/high E‐cadherin expression subtype. A significant correlation between JAG1 expression and KRAS status was detected in groups stratified as high E‐cadherin expression. In vitro studies suggested that RAS‐MEK‐MAP kinase and the Wnt pathways positively regulated JAG1 expression. Gene silencing with siJAG1 indicated that JAG1 promotes the transition from epithelial to mesenchymal characteristics and cell growth. High expression of JAG1 is regulated by various pathways and is associated with poor prognosis through promoting the epithelial to mesenchymal transition and cell proliferation or maintaining cell survival in CRC.
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Affiliation(s)
- Masakazu Sugiyama
- Department of Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Eiji Oki
- Department of Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Yu Nakaji
- Department of Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.,Department of Anatomic Pathology, Pathological Sciences, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Satoshi Tsutsumi
- Department of Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Naomi Ono
- Department of Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Ryota Nakanishi
- Department of Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Masahiko Sugiyama
- Department of Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Yuichiro Nakashima
- Department of Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Hideto Sonoda
- Department of Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Kippei Ohgaki
- Department of Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Nami Yamashita
- Department of Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Hiroshi Saeki
- Department of Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Shinji Okano
- Department of Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Hiroyuki Kitao
- Department of Molecular Oncology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Masaru Morita
- Department of Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Yoshinao Oda
- Department of Anatomic Pathology, Pathological Sciences, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Yoshihiko Maehara
- Department of Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
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113
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Chin AM, Hill DR, Aurora M, Spence JR. Morphogenesis and maturation of the embryonic and postnatal intestine. Semin Cell Dev Biol 2017; 66:81-93. [PMID: 28161556 DOI: 10.1016/j.semcdb.2017.01.011] [Citation(s) in RCA: 124] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2016] [Revised: 01/28/2017] [Accepted: 01/30/2017] [Indexed: 12/12/2022]
Abstract
The intestine is a vital organ responsible for nutrient absorption, bile and waste excretion, and a major site of host immunity. In order to keep up with daily demands, the intestine has evolved a mechanism to expand the absorptive surface area by undergoing a morphogenetic process to generate finger-like units called villi. These villi house specialized cell types critical for both absorbing nutrients from food, and for protecting the host from commensal and pathogenic microbes present in the adult gut. In this review, we will discuss mechanisms that coordinate intestinal development, growth, and maturation of the small intestine, starting from the formation of the early gut tube, through villus morphogenesis and into early postnatal life when the intestine must adapt to the acquisition of nutrients through food intake, and to interactions with microbes.
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Affiliation(s)
- Alana M Chin
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, United States
| | - David R Hill
- Department of Internal Medicine, Division of Gastroenterology, University of Michigan Medical School, Ann Arbor, MI, United States
| | - Megan Aurora
- Department of Pediatrics, Division of Neonatal-Perinatal Medicine, University of Michigan Medical School, Ann Arbor, MI, United States
| | - Jason R Spence
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, United States; Department of Internal Medicine, Division of Gastroenterology, University of Michigan Medical School, Ann Arbor, MI, United States; Center for Organogenesis, University of Michigan Medical School, Ann Arbor, MI, United States.
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114
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Tóth B, Ben-Moshe S, Gavish A, Barkai N, Itzkovitz S. Early commitment and robust differentiation in colonic crypts. Mol Syst Biol 2017; 13:902. [PMID: 28049136 PMCID: PMC5293156 DOI: 10.15252/msb.20167283] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Tissue stem cells produce a constant flux of differentiated cells with distinct proportions. Here, we show that stem cells in colonic crypts differentiate early to form precisely 1:3 ratio of secretory to absorptive cells. This precision is surprising, as there are only eight stem cells making irreversible fate decisions, and so large stochastic effects of this small pool should have yielded much larger noise in cell proportions. We use single molecule FISH, lineage‐tracing mice and simulations to identify the homeostatic mechanisms facilitating robust proportions. We find that Delta‐Notch lateral inhibition operates in a restricted spatial zone to reduce initial noise in cell proportions. Increased dwell time and dispersive migration of secretory cells further averages additional variability added during progenitor divisions and breaks up continuous patches of same‐fate cells. These noise‐reducing mechanisms resolve the trade‐off between early commitment and robust differentiation and ensure spatially uniform spread of secretory cells. Our findings may apply to other cases where small progenitor pools expand to give rise to precise tissue cell proportions.
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Affiliation(s)
- Beáta Tóth
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Shani Ben-Moshe
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Avishai Gavish
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Naama Barkai
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Shalev Itzkovitz
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
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115
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Huang T, Zhou Y, Cheng ASL, Yu J, To KF, Kang W. NOTCH receptors in gastric and other gastrointestinal cancers: oncogenes or tumor suppressors? Mol Cancer 2016; 15:80. [PMID: 27938406 PMCID: PMC5148895 DOI: 10.1186/s12943-016-0566-7] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Accepted: 12/01/2016] [Indexed: 12/18/2022] Open
Abstract
Gastric cancer (GC) ranks the most common cancer types and is one of the leading causes of cancer-related death. Due to delayed diagnosis and high metastatic frequency, 5-year survival rate of GC is rather low. It is a complex disease resulting from the interaction between environmental factors and host genetic alterations that deregulate multiple signaling pathways. The Notch signaling pathway, a highly conserved system in the regulation of the fate in several cell types, plays a pivotal role in cell differentiation, survival and proliferation. Notch is also one of the most commonly activated signaling pathways in tumors and its aberrant activation plays a key role in cancer advancement. Whether Notch cascade exerts oncogenic or tumor suppressive function in different cancer types depends on the cellular context. Mammals have four NOTCH receptors that modulate Notch pathway activity. In this review, we provide a comprehensive summary on the functional role of NOTCH receptors in gastric and other gastrointestinal cancers. Increasing knowledge of NOTCH receptors in gastrointestinal cancers will help us recognize the underlying mechanisms of Notch signaling and develop novel therapeutic strategies for GC.
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Affiliation(s)
- Tingting Huang
- Department of Anatomical and Cellular Pathology, State Key Laboratory of Oncology in South China, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, N.T, Hong Kong, SAR, People's Republic of China.,Institute of Digestive Disease, Partner State Key Laboratory of Digestive Disease, The Chinese University of Hong Kong, Hong Kong, SAR, People's Republic of China.,Li Ka Shing Institute of Health Science, Sir Y.K. Pao Cancer Center, The Chinese University of Hong Kong, Hong Kong, SAR, People's Republic of China.,Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen, People's Republic of China
| | - Yuhang Zhou
- Department of Anatomical and Cellular Pathology, State Key Laboratory of Oncology in South China, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, N.T, Hong Kong, SAR, People's Republic of China.,Institute of Digestive Disease, Partner State Key Laboratory of Digestive Disease, The Chinese University of Hong Kong, Hong Kong, SAR, People's Republic of China.,Li Ka Shing Institute of Health Science, Sir Y.K. Pao Cancer Center, The Chinese University of Hong Kong, Hong Kong, SAR, People's Republic of China
| | - Alfred S L Cheng
- Institute of Digestive Disease, Partner State Key Laboratory of Digestive Disease, The Chinese University of Hong Kong, Hong Kong, SAR, People's Republic of China.,Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen, People's Republic of China.,School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, People's Republic of China
| | - Jun Yu
- Institute of Digestive Disease, Partner State Key Laboratory of Digestive Disease, The Chinese University of Hong Kong, Hong Kong, SAR, People's Republic of China.,Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen, People's Republic of China.,Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Hong Kong, People's Republic of China
| | - Ka Fai To
- Department of Anatomical and Cellular Pathology, State Key Laboratory of Oncology in South China, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, N.T, Hong Kong, SAR, People's Republic of China. .,Institute of Digestive Disease, Partner State Key Laboratory of Digestive Disease, The Chinese University of Hong Kong, Hong Kong, SAR, People's Republic of China. .,Li Ka Shing Institute of Health Science, Sir Y.K. Pao Cancer Center, The Chinese University of Hong Kong, Hong Kong, SAR, People's Republic of China. .,Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen, People's Republic of China.
| | - Wei Kang
- Department of Anatomical and Cellular Pathology, State Key Laboratory of Oncology in South China, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, N.T, Hong Kong, SAR, People's Republic of China. .,Institute of Digestive Disease, Partner State Key Laboratory of Digestive Disease, The Chinese University of Hong Kong, Hong Kong, SAR, People's Republic of China. .,Li Ka Shing Institute of Health Science, Sir Y.K. Pao Cancer Center, The Chinese University of Hong Kong, Hong Kong, SAR, People's Republic of China. .,Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen, People's Republic of China.
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116
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Role of Src Family Kinases in Regulation of Intestinal Epithelial Homeostasis. Mol Cell Biol 2016; 36:2811-2823. [PMID: 27550814 DOI: 10.1128/mcb.00311-16] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 06/21/2016] [Accepted: 08/18/2016] [Indexed: 01/15/2023] Open
Abstract
Proper regulation of epithelial cell turnover is important for the structural integrity and homeostasis of various tissues, including the intestine. Here we show that ablation of Csk, a negative regulator of Src family kinases (SFKs), specifically in intestinal epithelial cells (IECs) resulted in the development of hyperplasia throughout the intestinal epithelium of mice. Such conditional ablation of Csk also increased the proliferative activity and turnover of IECs, disturbed the differentiation of Paneth and goblet cells, reduced the number of intestinal stem cells, and attenuated the expression of Wnt target genes in the intestine. Moreover, the tyrosine phosphorylation of focal adhesion kinase (FAK) and the activities of both Rac and Yes-associated protein (YAP) were increased in intestinal crypts or organoids of the mutant mice, whereas inhibition of Rac or YAP activity rescued the mutant phenotypes. Our results thus suggest that SFKs promote the proliferation of IECs in intestinal crypts through activation of Rac or YAP and that they thereby contribute to the proper regulation of IEC turnover and intestinal homeostasis.
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117
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Fine-Tuning of the Kaposi's Sarcoma-Associated Herpesvirus Life Cycle in Neighboring Cells through the RTA-JAG1-Notch Pathway. PLoS Pathog 2016; 12:e1005900. [PMID: 27760204 PMCID: PMC5070770 DOI: 10.1371/journal.ppat.1005900] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Accepted: 08/27/2016] [Indexed: 12/16/2022] Open
Abstract
Kaposi’s sarcoma (KS)-associated herpesvirus (KSHV) is an oncogenic pathogen that displays latent and lytic life cycles. In KS lesions, infiltrated immune cells, secreted viral and/or cellular cytokines, and hypoxia orchestrate a chronic pro-lytic microenvironment that can promote KSHV reactivation. However, only a small subset of viruses spontaneously undergoes lytic replication in this pro-lytic microenvironment while the majority remains in latency. Here, we show that the expression of the Notch ligand JAG1 is induced by KSHV-encoded replication and transcription activator (RTA) during reactivation. JAG1 up-regulation activates Notch signaling in neighboring cells and prevents viral lytic replication. The suppression of JAG1 and Notch1 with inhibitors or small interfering RNA promotes lytic replication in the presence of RTA induction or under conditions of hypoxia. The underlying mechanism involves the Notch downstream effector hairy and enhancer of split 1 (Hes1), which directly binds lytic gene promoters and attenuates viral lytic gene expression. RTA interacts with lymphoid enhancer-binding factor 1 (LEF1), disrupts LEF1/Groucho/TLE suppressive complexes and releases LEF1 to activate JAG1 expression. Taken together, our results suggest that cells with viral lytic replication can inhibit KSHV reactivation in neighboring cells through an RTA-JAG1-Notch pathway. These data provide insight into the mechanism by which the virus maintains the balance between lytic and latent infection in the pro-lytic tumor microenvironment. KSHV infected cells display significant heterogeneity in viral lytic replication within the universal pro-lytic inflammatory milieu, suggesting that the balance between latency and reactivation is carefully regulated. This fine-tuned regulatory mechanism is essential for KSHV to persist in the host and drive cells to malignancy. In the present study, we show that KSHV can usurp the Notch signaling pathway to inhibit the viral lytic life cycle in neighboring cells. Notch signaling in surrounding cells can be activated through an RTA-JAG1-Notch pathway initiated by cells in which KSHV is reactivated. Activated Notch inhibits KSHV reactivation through its downstream effector Hes1. These findings suggest that the ability of Notch to determine the fate of adjacent cells is hijacked by KSHV to maintain its life cycle, providing a mechanistic explanation for the phenomenon by which only a small fraction of viruses enters lytic replication in the common pro-lytic microenvironment.
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118
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Takada Y, Fukuda A, Chiba T, Seno H. Brg1 plays an essential role in development and homeostasis of the duodenum through regulation of Notch signaling. Development 2016; 143:3532-3539. [PMID: 27510977 DOI: 10.1242/dev.141549] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Accepted: 07/28/2016] [Indexed: 12/16/2022]
Abstract
Brg1, a core subunit of the SWI/SNF chromatin remodeling complex, is essential for development and homeostasis of various organs. However, the functional role of Brg1 in intestinal development and homeostasis, and the underlying molecular mechanism, remain unknown. We found that deletion of Brg1 in the mouse intestine resulted in growth impairment and early death associated with abnormal crypt-villous formation, skewed differentiation into secretory lineage cells, markedly increased apoptosis, and stem cell loss in the duodenum. Furthermore, we found that the Notch signaling pathway was dramatically downregulated in Brg1-deficient duodenum. Remarkably, overexpression of the Notch1 intercellular domain (ICD) partially reversed the prognosis of intestinal Brg1 mutant mice. Notch1 ICD overexpression rescued morphogenesis, prevented over-differentiation into secretory lineage cells, and restored apoptosis to normal levels in Brg1-deficient duodenum, although stem cell loss was not rescued. Our data demonstrate that Brg1 plays an essential role in development and homeostasis, including morphogenesis, stem cell differentiation and cell survival in the duodenum. Mechanistically, the rescue of the intestinal Brg1 mutant phenotype by overexpression of the Notch1 ICD indicates that Notch signaling is a key downstream target that mediates the effects of Brg1.
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Affiliation(s)
- Yutaka Takada
- Department of Gastroenterology and Hepatology, Kyoto University Graduate School of Medicine, Kyoto 6068507, Japan
| | - Akihisa Fukuda
- Department of Gastroenterology and Hepatology, Kyoto University Graduate School of Medicine, Kyoto 6068507, Japan
| | - Tsutomu Chiba
- Department of Gastroenterology and Hepatology, Kyoto University Graduate School of Medicine, Kyoto 6068507, Japan
| | - Hiroshi Seno
- Department of Gastroenterology and Hepatology, Kyoto University Graduate School of Medicine, Kyoto 6068507, Japan
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119
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Lemmon MA, Freed DM, Schlessinger J, Kiyatkin A. The Dark Side of Cell Signaling: Positive Roles for Negative Regulators. Cell 2016; 164:1172-1184. [PMID: 26967284 DOI: 10.1016/j.cell.2016.02.047] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Indexed: 12/12/2022]
Abstract
Cell signaling is dominated by analyzing positive responses to stimuli. Signal activation is balanced by negative regulators that are generally considered to terminate signaling. Rather than exerting only negative effects, however, many such regulators play important roles in enhancing cell-signaling control. Considering responses downstream of selected cell-surface receptors, we discuss how receptor internalization affects signaling specificity and how rapid kinase/phosphatase and GTP/GDP cycles increase responsiveness and allow kinetic proofreading in receptor signaling. We highlight the blurring of distinctions between positive and negative signals, recasting signal termination as the response to a switch-like transition into a new cellular state.
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Affiliation(s)
- Mark A Lemmon
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520, USA; Yale Cancer Biology Institute, West Haven, CT 06516, USA.
| | - Daniel M Freed
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520, USA; Yale Cancer Biology Institute, West Haven, CT 06516, USA
| | - Joseph Schlessinger
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520, USA; Yale Cancer Biology Institute, West Haven, CT 06516, USA
| | - Anatoly Kiyatkin
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520, USA; Yale Cancer Biology Institute, West Haven, CT 06516, USA
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120
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Ratanasirintrawoot S, Israsena N. Stem Cells in the Intestine: Possible Roles in Pathogenesis of Irritable Bowel Syndrome. J Neurogastroenterol Motil 2016; 22:367-82. [PMID: 27184041 PMCID: PMC4930294 DOI: 10.5056/jnm16023] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Accepted: 03/08/2016] [Indexed: 12/13/2022] Open
Abstract
Irritable bowel syndrome is one of the most common functional gastrointestinal (GI) disorders that significantly impair quality of life in patients. Current available treatments are still not effective and the pathophysiology of this condition remains unclearly defined. Recently, research on intestinal stem cells has greatly advanced our understanding of various GI disorders. Alterations in conserved stem cell regulatory pathways such as Notch, Wnt, and bone morphogenic protein/TGF-β have been well documented in diseases such as inflammatory bowel diseases and cancer. Interaction between intestinal stem cells and various signals from their environment is important for the control of stem cell self-renewal, regulation of number and function of specific intestinal cell types, and maintenance of the mucosal barrier. Besides their roles in stem cell regulation, these signals are also known to have potent effects on immune cells, enteric nervous system and secretory cells in the gut, and may be responsible for various aspects of pathogenesis of functional GI disorders, including visceral hypersensitivity, altered gut motility and low grade gut inflammation. In this article, we briefly summarize the components of these signaling pathways, how they can be modified by extrinsic factors and novel treatments, and provide evidenced support of their roles in the inflammation processes. Furthermore, we propose how changes in these signals may contribute to the symptom development and pathogenesis of irritable bowel syndrome.
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Affiliation(s)
- Sutheera Ratanasirintrawoot
- Stem Cell and Cell Therapy Research Unit, Chulalongkorn University, Bangkok, Thailand.,Department of Research Affairs, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Nipan Israsena
- Stem Cell and Cell Therapy Research Unit, Chulalongkorn University, Bangkok, Thailand.,Department of Pharmacology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
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121
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Demitrack ES, Samuelson LC. Notch regulation of gastrointestinal stem cells. J Physiol 2016; 594:4791-803. [PMID: 26848053 DOI: 10.1113/jp271667] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Accepted: 01/19/2016] [Indexed: 12/11/2022] Open
Abstract
The gastrointestinal (GI) tract epithelium is continuously replenished by actively cycling stem and progenitor cells. These cell compartments are regulated to balance proliferation and stem cell renewal with differentiation into the various mature cell types to maintain tissue homeostasis. In this topical review we focus on the role of the Notch signalling pathway to regulate GI stem cell function in adult small intestine and stomach. We first present the current view of stem and progenitor cell populations in these tissues and then summarize the studies that have established the Notch pathway as a key regulator of gastric and intestinal stem cell function. Notch signalling has been shown to be a niche factor required for maintenance of GI stem cells in both tissues. In addition, Notch has been described to regulate epithelial cell differentiation. Recent studies have revealed key similarities and differences in how Notch regulates stem cell function in the stomach compared to intestine. We summarize the literature regarding Notch regulation of GI stem cell proliferation and differentiation, highlighting tissue-specific functions to compare and contrast Notch in the stomach and intestine.
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Affiliation(s)
- Elise S Demitrack
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
| | - Linda C Samuelson
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA.,Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
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122
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Abstract
The Hippo pathway is a signalling cascade conserved from Drosophila melanogaster to mammals. The mammalian core kinase components comprise MST1 and MST2, SAV1, LATS1 and LATS2 and MOB1A and MOB1B. The transcriptional co-activators YAP1 and TAZ are the downstream effectors of the Hippo pathway and regulate target gene expression. Hippo signalling has crucial roles in the control of organ size, tissue homeostasis and regeneration, and dysregulation of the Hippo pathway can lead to uncontrolled cell growth and malignant transformation. Mammalian intestine consists of a stem cell compartment as well as differentiated cells, and its ability to regenerate rapidly after injury makes it an excellent model system to study tissue homeostasis, regeneration and tumorigenesis. Several studies have established the important role of the Hippo pathway in these processes. In addition, crosstalk between Hippo and other signalling pathways provides tight, yet versatile, regulation of tissue homeostasis. In this Review, we summarize studies on the role of the Hippo pathway in the intestine on these physiological processes and the underlying mechanisms responsible, and discuss future research directions and potential therapeutic strategies targeting Hippo signalling in intestinal disease.
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123
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Roulis M, Flavell RA. Fibroblasts and myofibroblasts of the intestinal lamina propria in physiology and disease. Differentiation 2016; 92:116-131. [PMID: 27165847 DOI: 10.1016/j.diff.2016.05.002] [Citation(s) in RCA: 119] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Revised: 04/19/2016] [Accepted: 05/03/2016] [Indexed: 01/14/2023]
Abstract
In this Review we summarize our current understanding of the biology of mesenchymal cells of the intestinal lamina propria focusing mainly on fibroblasts and myofibroblasts. The topics covered include 1) the embryonic origin of mesenchymal cells of the intestinal lamina propria and their heterogeneity in adults, 2) the role of the mesenchyme in intestinal development, 3) the physiological function of fibroblasts and myofibroblasts in adults as part of the intestinal stem cell niche and the mucosal immune system and 4) the involvement of fibroblasts and myofibroblasts in epithelial homeostasis upon injury and in the pathogenesis of diseases such as Inflammatory Bowel Diseases, fibrosis and cancer. We emphasize studies addressing the function of intestinal mesenchymal cells in vivo, and also discuss major open questions and current challenges in this field.
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Affiliation(s)
- Manolis Roulis
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Richard A Flavell
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT 06520, USA; Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT 06520, USA.
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124
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Gonneaud A, Turgeon N, Boudreau F, Perreault N, Rivard N, Asselin C. Distinct Roles for Intestinal Epithelial Cell-Specific Hdac1 and Hdac2 in the Regulation of Murine Intestinal Homeostasis. J Cell Physiol 2016; 231:436-48. [PMID: 26174178 DOI: 10.1002/jcp.25090] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2015] [Accepted: 07/07/2015] [Indexed: 02/06/2023]
Abstract
The intestinal epithelium responds to and transmits signals from the microbiota and the mucosal immune system to insure intestinal homeostasis. These interactions are in part conveyed by epigenetic modifications, which respond to environmental changes. Protein acetylation is an epigenetic signal regulated by histone deacetylases, including Hdac1 and Hdac2. We have previously shown that villin-Cre-inducible intestinal epithelial cell (IEC)-specific Hdac1 and Hdac2 deletions disturb intestinal homeostasis. To determine the role of Hdac1 and Hdac2 in the regulation of IEC function and the establishment of the dual knockout phenotype, we have generated villin-Cre murine models expressing one Hdac1 allele without Hdac2, or one Hdac2 allele without Hdac1. We have also investigated the effect of short-term deletion of both genes in naphtoflavone-inducible Ah-Cre and tamoxifen-inducible villin-Cre(ER) mice. Mice with one Hdac1 allele displayed normal tissue architecture, but increased sensitivity to DSS-induced colitis. In contrast, mice with one Hdac2 allele displayed intestinal architecture defects, increased proliferation, decreased goblet cell numbers as opposed to Paneth cells, increased immune cell infiltration associated with fibrosis, and increased sensitivity to DSS-induced colitis. In comparison to dual knockout mice, intermediary activation of Notch, mTOR, and Stat3 signaling pathways was observed. While villin-Cre(ER) Hdac1 and Hdac2 deletions led to an impaired epithelium and differentiation defects, Ah-Cre-mediated deletion resulted in blunted proliferation associated with the induction of a DNA damage response. Our results suggest that IEC determination and intestinal homeostasis are highly dependent on Hdac1 and Hdac2 activity levels, and that changes in the IEC acetylome may alter the mucosal environment.
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Affiliation(s)
- Alexis Gonneaud
- Département d'anatomie et biologie cellulaire, Pavillon de recherche appliquée sur le cancer, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Naomie Turgeon
- Département d'anatomie et biologie cellulaire, Pavillon de recherche appliquée sur le cancer, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - François Boudreau
- Département d'anatomie et biologie cellulaire, Pavillon de recherche appliquée sur le cancer, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Nathalie Perreault
- Département d'anatomie et biologie cellulaire, Pavillon de recherche appliquée sur le cancer, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Nathalie Rivard
- Département d'anatomie et biologie cellulaire, Pavillon de recherche appliquée sur le cancer, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Claude Asselin
- Département d'anatomie et biologie cellulaire, Pavillon de recherche appliquée sur le cancer, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec, Canada
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125
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van Rijn JM, Schneeberger K, Wiegerinck CL, Nieuwenhuis EES, Middendorp S. Novel approaches: Tissue engineering and stem cells--In vitro modelling of the gut. Best Pract Res Clin Gastroenterol 2016; 30:281-93. [PMID: 27086891 DOI: 10.1016/j.bpg.2016.03.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Accepted: 03/05/2016] [Indexed: 01/31/2023]
Abstract
In many intestinal diseases, the function of the epithelial lining is impaired. In this review, we describe the recent developments of in vitro intestinal stem cell cultures. When these stem cells are grown in 3D structures (organoids), they provide a model of the intestinal epithelium, which is closely similar to the growth and development of the in vivo gut. This model provides a new tool to study various diseases of malabsorption in functional detail and therapeutic applications, which could not be achieved with traditional cell lines. First, we describe the organization and function of the healthy small intestinal epithelium. Then, we discuss the establishment of organoid cultures and how these structures represent the healthy epithelium. Finally, we discuss organoid cultures as a tool for studying intrinsic properties of the epithelium, as a model for intestinal disease, and as a possible source for stem cell transplantations.
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Affiliation(s)
- Jorik M van Rijn
- Division of Pediatrics, Department of Paediatric Gastroenterology, Wilhelmina Children's Hospital, University Medical Centre Utrecht, Regenerative Medicine Center Utrecht, Uppsalalaan 6, 3584 CT, Utrecht, The Netherlands
| | - Kerstin Schneeberger
- Division of Pediatrics, Department of Paediatric Gastroenterology, Wilhelmina Children's Hospital, University Medical Centre Utrecht, Regenerative Medicine Center Utrecht, Uppsalalaan 6, 3584 CT, Utrecht, The Netherlands
| | - Caroline L Wiegerinck
- Division of Pediatrics, Department of Paediatric Gastroenterology, Wilhelmina Children's Hospital, University Medical Centre Utrecht, Regenerative Medicine Center Utrecht, Uppsalalaan 6, 3584 CT, Utrecht, The Netherlands
| | - Edward E S Nieuwenhuis
- Division of Pediatrics, Department of Paediatric Gastroenterology, Wilhelmina Children's Hospital, University Medical Centre Utrecht, Regenerative Medicine Center Utrecht, Uppsalalaan 6, 3584 CT, Utrecht, The Netherlands
| | - Sabine Middendorp
- Division of Pediatrics, Department of Paediatric Gastroenterology, Wilhelmina Children's Hospital, University Medical Centre Utrecht, Regenerative Medicine Center Utrecht, Uppsalalaan 6, 3584 CT, Utrecht, The Netherlands
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126
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Abstract
Notch controls skeletogenesis, but its role in the remodeling of adult bone remains conflicting. In mature mice, the skeleton can become osteopenic or osteosclerotic depending on the time point at which Notch is activated or inactivated. Using adult EGFP reporter mice, we find that Notch expression is localized to osteocytes embedded within bone matrix. Conditional activation of Notch signaling in osteocytes triggers profound bone formation, mainly due to increased mineralization, which rescues both age-associated and ovariectomy-induced bone loss and promotes bone healing following osteotomy. In parallel, mice rendered haploinsufficient in γ-secretase presenilin-1 (Psen1), which inhibits downstream Notch activation, display almost-absent terminal osteoblast differentiation. Consistent with this finding, pharmacologic or genetic disruption of Notch or its ligand Jagged1 inhibits mineralization. We suggest that stimulation of Notch signaling in osteocytes initiates a profound, therapeutically relevant, anabolic response.
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127
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Murata A, Hayashi SI. Notch-Mediated Cell Adhesion. BIOLOGY 2016; 5:biology5010005. [PMID: 26784245 PMCID: PMC4810162 DOI: 10.3390/biology5010005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Revised: 01/12/2016] [Accepted: 01/13/2016] [Indexed: 02/06/2023]
Abstract
Notch family members are generally recognized as signaling molecules that control various cellular responses in metazoan organisms. Early fly studies and our mammalian studies demonstrated that Notch family members are also cell adhesion molecules; however, information on the physiological roles of this function and its origin is limited. In this review, we discuss the potential present and ancestral roles of Notch-mediated cell adhesion in order to explore its origin and the initial roles of Notch family members dating back to metazoan evolution. We hypothesize that Notch family members may have initially emerged as cell adhesion molecules in order to mediate multicellularity in the last common ancestor of metazoan organisms.
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Affiliation(s)
- Akihiko Murata
- Department of Molecular and Cellular Biology, Division of Immunology, School of Life Science, Faculty of Medicine, Tottori University, Yonago, Tottori 683-8503, Japan.
| | - Shin-Ichi Hayashi
- Department of Molecular and Cellular Biology, Division of Immunology, School of Life Science, Faculty of Medicine, Tottori University, Yonago, Tottori 683-8503, Japan.
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128
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Okamoto R, Watanabe M. Role of epithelial cells in the pathogenesis and treatment of inflammatory bowel disease. J Gastroenterol 2016; 51:11-21. [PMID: 26138071 DOI: 10.1007/s00535-015-1098-4] [Citation(s) in RCA: 137] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2015] [Accepted: 06/15/2015] [Indexed: 02/04/2023]
Abstract
In the past decades, continuous effort has been paid to deeply understanding the pathophysiology of inflammatory bowel diseases (IBD), such as ulcerative colitis or Crohn's disease. As the disease typically arises as chronic inflammation of the gastrointestinal mucosa, research has been focused on how such an uncontrolled, deleterious immune response may arise and persist in a certain cohort of patients. Based on those immunologic analyses, the establishment of anti-TNF-α therapy, and the following series of biologic agents achieved great success and dramatically changed the therapeutic strategy of IBD patients. However, to guarantee long-term remission of the disease, the therapeutic standard has been raised to achieve "mucosal healing", which requires complete repair of the gastrointestinal mucosa. Recent studies have revealed the unexpected importance of epithelial cells in the pathophysiology of IBD. The general barrier function as well as the cell lineage-specific functions have been deeply attributed to the development of chronic intestinal inflammation. Also, the groundbreaking establishment of the in vitro intestinal stem cell culture system has opened up a way of developing stem cell transplantation therapy to treat otherwise refractory ulcers that may persist in IBD patients. In this review, we would like to focus on the role of epithelial cells in the pathophysiology of IBD, and also give a perspective to the upcoming development of regenerative therapies that may become one of the therapeutic choices to achieve mucosal healing in refractory patients of IBD.
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Affiliation(s)
- Ryuichi Okamoto
- Center for Stem Cell and Regenerative Medicine, Graduate School, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-Ku, Tokyo, 113-8519, Japan.
| | - Mamoru Watanabe
- Department of Gastroenterology and Hepatology, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan
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129
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Abstract
A disintegrin and metalloproteinases (ADAMs) are a family of cell surface proteases that regulate diverse cellular functions, including cell adhesion, migration, cellular signaling, and proteolysis. Proteolytically active ADAMs are responsible for ectodomain shedding of membrane-associated proteins. ADAMs rapidly modulate key cell signaling pathways in response to changes in the extracellular environment (e.g., inflammation) and play a central role in coordinating intercellular communication within the local microenvironment. ADAM10 and ADAM17 are the most studied members of the ADAM family in the gastrointestinal tract. ADAMs regulate many cellular processes associated with intestinal development, cell fate specification, and the maintenance of intestinal stem cell/progenitor populations. Several signaling pathway molecules that undergo ectodomain shedding by ADAMs [e.g., ligands and receptors from epidermal growth factor receptor (EGFR)/ErbB and tumor necrosis factor α (TNFα) receptor (TNFR) families] help drive and control intestinal inflammation and injury/repair responses. Dysregulation of these processes through aberrant ADAM expression or sustained ADAM activity is linked to chronic inflammation, inflammation-associated cancer, and tumorigenesis.
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Affiliation(s)
- Jennifer C Jones
- Cell Biology, Stem Cells, and Development Program and.,Division of Gastroenterology, Hepatology, and Nutrition and Department of Pediatrics, University of Colorado Medical School, Aurora, Colorado 80045; , ,
| | - Shelly Rustagi
- Division of Gastroenterology, Hepatology, and Nutrition and Department of Pediatrics, University of Colorado Medical School, Aurora, Colorado 80045; , ,
| | - Peter J Dempsey
- Cell Biology, Stem Cells, and Development Program and.,Division of Gastroenterology, Hepatology, and Nutrition and Department of Pediatrics, University of Colorado Medical School, Aurora, Colorado 80045; , ,
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130
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Sirakov M, Boussouar A, Kress E, Frau C, Lone IN, Nadjar J, Angelov D, Plateroti M. The thyroid hormone nuclear receptor TRα1 controls the Notch signaling pathway and cell fate in murine intestine. Development 2015; 142:2764-74. [PMID: 26286942 DOI: 10.1242/dev.121962] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Thyroid hormones control various aspects of gut development and homeostasis. The best-known example is in gastrointestinal tract remodeling during amphibian metamorphosis. It is well documented that these hormones act via the TR nuclear receptors, which are hormone-modulated transcription factors. Several studies have shown that thyroid hormones regulate the expression of several genes in the Notch signaling pathway, indicating a possible means by which they participate in the control of gut physiology. However, the mechanisms and biological significance of this control have remained unexplored. Using multiple in vivo and in vitro approaches, we show that thyroid hormones positively regulate Notch activity through the TRα1 receptor. From a molecular point of view, TRα1 indirectly controls Notch1, Dll1, Dll4 and Hes1 expression but acts as a direct transcriptional regulator of the Jag1 gene by binding to a responsive element in the Jag1 promoter. Our findings show that the TRα1 nuclear receptor plays a key role in intestinal crypt progenitor/stem cell biology by controlling the Notch pathway and hence the balance between cell proliferation and cell differentiation.
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Affiliation(s)
- Maria Sirakov
- Centre de Génétique et de Physiologie Moléculaire et Cellulaire, Université Claude Bernard Lyon 1, 16 Rue Raphael Dubois, Villeurbanne 69622, France
| | - Amina Boussouar
- Centre de Génétique et de Physiologie Moléculaire et Cellulaire, Université Claude Bernard Lyon 1, 16 Rue Raphael Dubois, Villeurbanne 69622, France
| | - Elsa Kress
- Centre de Génétique et de Physiologie Moléculaire et Cellulaire, Université Claude Bernard Lyon 1, 16 Rue Raphael Dubois, Villeurbanne 69622, France
| | - Carla Frau
- Centre de Génétique et de Physiologie Moléculaire et Cellulaire, Université Claude Bernard Lyon 1, 16 Rue Raphael Dubois, Villeurbanne 69622, France
| | - Imtiaz Nisar Lone
- Laboratoire de Biologie Moléculaire de la cellule, Ecole Normale Supérieure de Lyon, 46 Allée d'Italie, Lyon 69007, France
| | - Julien Nadjar
- Centre de Génétique et de Physiologie Moléculaire et Cellulaire, Université Claude Bernard Lyon 1, 16 Rue Raphael Dubois, Villeurbanne 69622, France
| | - Dimitar Angelov
- Laboratoire de Biologie Moléculaire de la cellule, Ecole Normale Supérieure de Lyon, 46 Allée d'Italie, Lyon 69007, France
| | - Michelina Plateroti
- Centre de Génétique et de Physiologie Moléculaire et Cellulaire, Université Claude Bernard Lyon 1, 16 Rue Raphael Dubois, Villeurbanne 69622, France
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131
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Goh VJ, Tan JSY, Tan BC, Seow C, Ong WY, Lim YC, Sun L, Ghosh S, Silver DL. Postnatal Deletion of Fat Storage-inducing Transmembrane Protein 2 (FIT2/FITM2) Causes Lethal Enteropathy. J Biol Chem 2015; 290:25686-99. [PMID: 26304121 DOI: 10.1074/jbc.m115.676700] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Indexed: 02/03/2023] Open
Abstract
Lipid droplets (LDs) are phylogenetically conserved cytoplasmic organelles that store neutral lipids within a phospholipid monolayer. LDs compartmentalize lipids and may help to prevent cellular damage caused by their excess or bioactive forms. FIT2 is a ubiquitously expressed transmembrane endoplasmic reticulum (ER) membrane protein that has previously been implicated in LD formation in mammalian cells and tissue. Recent data indicate that FIT2 plays an essential role in fat storage in an in vivo constitutive adipose FIT2 knock-out mouse model, but the physiological effects of postnatal whole body FIT2 depletion have never been studied. Here, we show that tamoxifen-induced FIT2 deletion using a whole body ROSA26CreER(T2)-driven FIT2 knock-out (iF2KO) mouse model leads to lethal intestinal pathology, including villus blunting and death of intestinal crypts, and loss of lipid absorption. iF2KO mice lose weight and die within 2 weeks after the first tamoxifen dose. At the cellular level, LDs failed to form in iF2KO enterocytes after acute oil challenge and instead accumulated within the ER. Intestinal bile acid transporters were transcriptionally dysregulated in iF2KO mice, leading to the buildup of bile acids within enterocytes. These data support the conclusion that FIT2 plays an essential role in regulating intestinal health and survival postnatally.
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Affiliation(s)
- Vera J Goh
- From the Signature Research Program in Cardiovascular and Metabolic Disorders, Duke-National University of Singapore Graduate Medical School, 8 College Road, 169857 Singapore and
| | - Jolene S Y Tan
- From the Signature Research Program in Cardiovascular and Metabolic Disorders, Duke-National University of Singapore Graduate Medical School, 8 College Road, 169857 Singapore and
| | - Bryan C Tan
- From the Signature Research Program in Cardiovascular and Metabolic Disorders, Duke-National University of Singapore Graduate Medical School, 8 College Road, 169857 Singapore and
| | - Colin Seow
- From the Signature Research Program in Cardiovascular and Metabolic Disorders, Duke-National University of Singapore Graduate Medical School, 8 College Road, 169857 Singapore and
| | - Wei-Yi Ong
- the Department of Anatomy and Neurobiology and Aging Research Programme, National University of Singapore, Singapore 119260, Singapore
| | - Yen Ching Lim
- From the Signature Research Program in Cardiovascular and Metabolic Disorders, Duke-National University of Singapore Graduate Medical School, 8 College Road, 169857 Singapore and
| | - Lei Sun
- From the Signature Research Program in Cardiovascular and Metabolic Disorders, Duke-National University of Singapore Graduate Medical School, 8 College Road, 169857 Singapore and
| | - Sujoy Ghosh
- From the Signature Research Program in Cardiovascular and Metabolic Disorders, Duke-National University of Singapore Graduate Medical School, 8 College Road, 169857 Singapore and
| | - David L Silver
- From the Signature Research Program in Cardiovascular and Metabolic Disorders, Duke-National University of Singapore Graduate Medical School, 8 College Road, 169857 Singapore and
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