• Pten
• Toll-like receptor
• immune responses
• intestinal epithelial cells

• crc, colorectal cancer
• pten, phosphatase and tensin homolog deleted on chromosome 10

Mutations in the HNF4A gene cause MODY1 and are associated with an increased risk of Type 2 diabetes mellitus. On the other hand, incretins are hormones that potentiate reductions in blood glucose levels. Given the established role of incretin-based therapy to treat diabetes and metabolic disorders, we investigated a possible regulatory link between intestinal epithelial HNF4α and glucose-dependent insulinotropic polypeptide (GIP), an incretin that is specifically produced by gut enteroendocrine cells. Conditional deletion of HNF4α in the whole intestinal epithelium was achieved by crossing Villin-Cre and Hnf4α^loxP/loxP C57BL/6 mouse models. GIP expression was measured by qPCR, immunofluorescence and ELISA. Gene transcription was assessed by luciferase and electrophoretic mobility shift assays. Metabolic parameters were analyzed by indirect calorimetry and dual-energy X-ray absorptiometry. HNF4α specific deletion in the intestine led to a reduction in GIP. HNF4α was able to positively control Gip transcriptional activity in collaboration with GATA-4 transcription factor. Glucose homeostasis and glucose-stimulated insulin secretion remained unchanged in HNF4α deficient mice. Changes in GIP production in these mice did not impact nutrition or energy metabolism under normal physiology but led to a reduction of bone area and mineral content, a well described physiological consequence of GIP deficiency. Our findings point to a novel regulatory role between intestinal HNF4α and GIP with possible functional impact on bone density.

• Microbiome
• Pten
• Toll-like receptor
• Tumor microenvironment
• Tumor prevention

A major risk factor of developing colorectal cancer (CRC) is the presence of chronic inflammation in the colon. In order to understand how inflammation contributes to CRC development, the present study focused on SHP-2, a tyrosine phosphatase encoded by PTPN11 gene in which polymorphisms have been shown to be markers of colitis susceptibility. Conversely, gain-of-function mutations in PTPN11 gene (E76 residue) have been found in certain sporadic CRC. Results shown herein demonstrate that SHP-2 expression was markedly increased in sporadic human adenomas but not in advanced colorectal tumors. SHP-2 silencing inhibited proliferative, invasive and tumoral properties of both intestinal epithelial cells (IECs) transformed by oncogenic KRAS and of human CRC cells. IEC-specific expression of a SHP-2^E76K activated mutant in mice was not sufficient to induce tumorigenesis but markedly promoted tumor growth under the Apc^Min/+ background. Conversely, mice with a conditional deletion of SHP-2 in IECs developed colitis-associated adenocarcinomas with age, associated with sustained activation of Wnt/β-catenin, NFκB and STAT3 signalings in the colonic mucosae. Moreover, SHP-2 epithelial deficiency considerably increased tumor load in Apc^Min/+ mice, shifting tumor incidence toward the colon. Overall, these results reveal that SHP-2 can exert opposing functions in the large intestine: it can promote or inhibit tumorigenesis depending of the inflammatory context.

• SHP-2
• colitis-associated cancer
• colorectal cancer
• mitogen-activated protein kinase
• oncogene

• Apc
• Lgr5
• Pten
• colon cancer
• obesity

• Adenomatous Polyposis Coli Protein/deficiency
• Adenomatous Polyposis Coli Protein/genetics
• Animals
• Carcinogenesis/genetics
• Diet, Fat-Restricted
• Diet, High-Fat
• Gastrointestinal Tract/cytology
• Gastrointestinal Tract/pathology
• Glucose/analysis
• Green Fluorescent Proteins/genetics
• Insulin/blood
• Male
• Mice, Transgenic
• Obesity/blood
• Obesity/genetics
• PTEN Phosphohydrolase/deficiency
• PTEN Phosphohydrolase/genetics
• Receptors, G-Protein-Coupled/genetics
• Stem Cells/pathology

• R00 AG037574 NIA NIH HHS
• R56 AG052981 NIA NIH HHS
• T32 AG023475 NIA NIH HHS
• P30 DK020541 NIDDK NIH HHS
• P30 AG038072 NIA NIH HHS
• S10 OD019961 NIH HHS
• P30 CA013330 NCI NIH HHS

• 14-3-3 proteins
• Akt
• Chromogranin A
• autophagy
• colitis
• differentiation

Polymorphisms in the PTPN11 gene encoding for the tyrosine phosphatase SHP‐2 were described in patients with ulcerative colitis. We have recently demonstrated that mice with an intestinal epithelial cell‐specific deletion of SHP‐2 (SHP‐2^IEC‐KO) develop severe colitis 1 month after birth. However, the mechanisms by which SHP‐2 deletion induces colonic inflammation remain to be elucidated. We generated SHP‐2^IEC‐KO mice lacking Myd88 exclusively in the intestinal epithelium. The colonic phenotype was histologically analyzed and cell differentiation was determined by electron microscopy and lysozyme or Alcian blue staining. Microbiota composition was analyzed by 16S sequencing. Results show that innate defense genes including those specific to Paneth cells were strongly up‐regulated in SHP‐2‐deficient colons. Expansion of intermediate cells (common progenitors of the Goblet and Paneth cell lineages) was found in the colon of SHP‐2^IEC‐KO mice whereas Goblet cell number was clearly diminished. These alterations in Goblet/intermediate cell ratio were noticed 2 weeks after birth, before the onset of inflammation and were associated with significant alterations in microbiota composition. Indeed, an increase in Enterobacteriaceae and a decrease in Firmicutes were observed in the colon of these mice, indicating that dysbiosis also occurred prior to inflammation. Importantly, loss of epithelial Myd88 expression inhibited colitis development in SHP‐2^IEC‐KO mice, rescued Goblet/intermediate cell ratio, and prevented NFκB hyperactivation and inflammation. These data indicate that SHP‐2 is functionally important for the maintenance of appropriate barrier function and host‐microbiota homeostasis in the large intestine. J. Cell. Physiol. 231: 2529–2540, 2016. © 2016 The Authors. Journal of Cellular Physiology published by Wiley Periodicals, Inc.

• MTORC1
• PTEN
• dormant
• fasting
• intestinal stem cells
• quiescent

• Epithelial
• Homeostasis
• Mammary
• PTEN

• Inflammatory Bowel Disease
• Innate Immunity
• Intestinal Epithelial Cells
• Pediatric

Intestinal epithelial cells express the Sonic and Indian hedgehog ligands. Despite the strong interest in gut hedgehog signaling in GI diseases, no studies have specifically addressed the singular role of intestinal epithelial cell Sonic hedgehog signaling. The aim of this study was to investigate the specific role of Sonic hedgehog in adult ileal epithelial homeostasis.

A Sonic hedgehog intestinal epithelial conditional knockout mouse model was generated. Assessment of ileal histological abnormalities, crypt epithelial cell proliferation, epithelial cell fate, junctional proteins, signaling pathways, as well as ultrastructural analysis of intracellular organelles were performed in control and mutant mice. Mice lacking intestinal epithelial Sonic Hedgehog displayed decreased ileal crypt/villus length, decreased crypt proliferation as well as a decrease in the number of ileal mucin-secreting goblet cells and antimicrobial peptide-secreting Paneth cells during adult life. These secretory cells also exhibited disruption of their secretory products in mutant mice. Ultrastructural microscopy analysis revealed a dilated ER lumen in secretory cells. This phenotype was also associated with a decrease in autophagy.

Altogether, these findings indicate that the loss of Sonic hedgehog can lead to ileal secretory cell modifications indicative of endoplasmic reticulum stress, accompanied by a significant reduction in autophagy.

• colorectal cancer
• transforming growth factor beta
• pten
• p21^cip1
• colon cancer

• Animals
• Carcinogenesis/drug effects
• Carcinogenesis/genetics
• Cell Cycle/drug effects
• Cell Cycle/genetics
• Cell Line, Tumor
• Colonic Neoplasms/genetics
• Colonic Neoplasms/metabolism
• Colonic Neoplasms/pathology
• Cyclin-Dependent Kinase Inhibitor p21/metabolism
• Cyclin-Dependent Kinases/antagonists & inhibitors
• Disease Progression
• Gene Expression Regulation, Neoplastic/drug effects
• Gene Expression Regulation, Neoplastic/genetics
• Gene Knockout Techniques
• Humans
• Intestinal Mucosa/drug effects
• Intestinal Mucosa/pathology
• Mice
• Mutation
• PTEN Phosphohydrolase/deficiency
• PTEN Phosphohydrolase/genetics
• Protein Kinase Inhibitors/pharmacology
• Protein Serine-Threonine Kinases/deficiency
• Protein Serine-Threonine Kinases/genetics
• Receptor, Transforming Growth Factor-beta Type II
• Receptors, Transforming Growth Factor beta/deficiency
• Receptors, Transforming Growth Factor beta/genetics
• Signal Transduction/drug effects
• Signal Transduction/genetics
• Transforming Growth Factor beta/metabolism

• P30 CA015704 NCI NIH HHS
• P01 CA077852 NCI NIH HHS
• U54 CA143862 NCI NIH HHS
• U01CA152756 NCI NIH HHS
• R01 CA115513 NCI NIH HHS
• R01CA115513 NCI NIH HHS
• U01 CA152756 NCI NIH HHS
• U54CA143862 NCI NIH HHS
• P01CA077852 NCI NIH HHS
• T32 CA080416 NCI NIH HHS
• P30CA15704 NCI NIH HHS

• AKT
• PI3 kinase
• colorectal cancer
• signaling
• therapy

AIM: To investigate the impact of phosphatase and tensin homolog (Pten) in the specification of intestinal enteroendocrine subpopulations.

METHODS: Using the Cre/loxP system, a mouse with conditional intestinal epithelial Pten deficiency was generated. Pten mutant mice and controls were sacrificed and small intestines collected for immunofluorescence and quantitative real-time polymerase chain reaction. Blood was collected on 16 h fasted mice by cardiac puncture. Enzyme-linked immunosorbent assay was used to measure blood circulating ghrelin, somatostatin (SST) and glucose-dependent insulinotropic peptide (GIP) levels.

RESULTS: Results show an unexpected dual regulatory role for epithelial Pten signalling in the specification/differentiation of enteroendocrine cell subpopulations in the small intestine. Our data indicate that Pten positively regulates chromogranin A (CgA) expressing subpopulations, including cells expressing secretin, ghrelin, gastrin and cholecystokinin (CCK). In contrast, Pten negatively regulates the enteroendocrine subtype specification of non-expressing CgA cells such as GIP and SST expressing cells.

CONCLUSION: The present results demonstrate that Pten signalling favours the enteroendocrine progenitor to specify into cells expressing CgA including those producing CCK, gastrin and ghrelin.

• Phosphatase and tensin homolog
• Enteroendocrine cells
• Intestinal epithelial cell specification
• Chromogranin A

• phosphatase and tensin homolog deleted on chromosome ten
• intestine
• cancer
• colon

• bone morphogenetic protein
• gastric cell lineages
• spasmolytic polypeptide-expressing metaplasia

• Animals
• Cell Communication
• Epithelium/immunology
• Gastrointestinal Tract/immunology
• HT29 Cells
• Humans
• Immunity, Mucosal/immunology
• Immunohistochemistry
• Interleukin-13/metabolism
• Mice
• MicroRNAs/immunology
• Reverse Transcriptase Polymerase Chain Reaction
• Signal Transduction
• T-Lymphocytes/immunology

The PTEN phosphatase acts on phosphatidylinositol 3,4,5-triphosphates resulting from phosphatidylinositol 3-kinase (PI3K) activation. PTEN expression has been shown to be decreased in colorectal cancer. Little is known however as to the specific cellular role of PTEN in human intestinal epithelial cells. The aim of this study was to investigate the role of PTEN in human colorectal cancer cells.

Caco-2/15, HCT116 and CT26 cells were infected with recombinant lentiviruses expressing a shRNA specifically designed to knock-down PTEN. The impact of PTEN downregulation was analyzed on cell polarization and differentiation, intercellular junction integrity (expression of cell-cell adhesion proteins, barrier function), migration (wound assay), invasion (matrigel-coated transwells) and on tumor and metastasis formation in mice. Electron microscopy analysis showed that lentiviral infection of PTEN shRNA significantly inhibited Caco-2/15 cell polarization, functional differentiation and brush border development. A strong reduction in claudin 1, 3, 4 and 8 was also observed as well as a decrease in transepithelial resistance. Loss of PTEN expression increased the spreading, migration and invasion capacities of colorectal cancer cells in vitro. PTEN downregulation also increased tumor size following subcutaneous injection of colorectal cancer cells in nude mice. Finally, loss of PTEN expression in HCT116 and CT26, but not in Caco-2/15, led to an increase in their metastatic potential following tail-vein injections in mice.

Altogether, these results indicate that PTEN controls cellular polarity, establishment of cell-cell junctions, paracellular permeability, migration and tumorigenic/metastatic potential of human colorectal cancer cells.

Although Hnf1α is crucial for pancreas and liver functions, it is believed to play a limited functional role for intestinal epithelial functions. The aim of this study was to assess the consequences of abrogating Hnf1α on the maintenance of adult small intestinal epithelial functions.

An Hnf1α knockout mouse model was used. Assessment of histological abnormalities, crypt epithelial cell proliferation, epithelial barrier, glucose transport and signalling pathways were measured in these animals. Changes in global gene expression were also analyzed. Mice lacking Hnf1α displayed increased crypt proliferation and intestinalomegaly as well as a disturbance of intestinal epithelial cell lineages production during adult life. This phenotype was associated with a decrease of the mucosal barrier function and lumen-to-blood glucose delivery. The mammalian target of rapamycin (mTOR) signalling pathway was found to be overly activated in the small intestine of adult Hnf1α mutant mice. The intestinal epithelium of Hnf1α null mice displayed a reduction of the enteroendocrine cell population. An impact was also observed on proper Paneth cell differentiation with abnormalities in the granule exocytosis pathway.

Together, these results unravel a functional role for Hnf1α in regulating adult intestinal growth and sustaining the functions of intestinal epithelial cell lineages.

• Animals
• Biological Transport/genetics
• Cell Differentiation
• Cell Proliferation
• Enterocytes/cytology
• Enterocytes/metabolism
• Enteroendocrine Cells/cytology
• Enteroendocrine Cells/metabolism
• Gene Deletion
• Gene Knockout Techniques
• Glucose/metabolism
• Hepatocyte Nuclear Factor 1-alpha/deficiency
• Hepatocyte Nuclear Factor 1-alpha/genetics
• Hepatocyte Nuclear Factor 1-alpha/metabolism
• Homeostasis/genetics
• Intestinal Mucosa/cytology
• Intestinal Mucosa/metabolism
• Intracellular Signaling Peptides and Proteins/metabolism
• Mice
• Paneth Cells/cytology
• Paneth Cells/metabolism
• Protein Serine-Threonine Kinases/metabolism
• Signal Transduction/genetics
• TOR Serine-Threonine Kinases
• Up-Regulation

• MOP-89770 Canadian Institutes of Health Research