Selective up-regulation of NMDA-NR1 receptor expression in myenteric plexus after TNBS induced colitis in rats

BACKGROUND: N-methyl-D-aspartic acid (NMDA) spinal cord receptors play an important role in the development of hyperalgesia following inflammation. It is unclear, however, if changes in NMDA subunit receptor gene expression in the colonic myenteric plexus are associated with colonic inflammation. We investigated regulation of NMDA-NR1 receptor gene expression in TNBS induced colitis in rats. Male Sprague-Dawley rats (150 g–250 g) were treated with 20 mg trinitrobenzene sulfonic acid (TNBS) diluted in 50% ethanol. The agents were delivered with a 24 gauge catheter inserted into the lumen of the colon. The animals were sacrificed at 2, 7, 14, 21, and 28 days after induction of the colitis, their descending colon was retrieved for reverse transcription-polymerase chain reaction; a subset of animals' distal colon was used for two-dimensional (2-D) western analysis and immunocytochemistry. RESULTS: NR1-exon 5 (N1) and NR1-exon 21 (C1) appeared 14, 21 and 28 days after TNBS treatment. NR1 pan mRNA was up-regulated at 14, 21, and 28 days. The NR1-exon 22 (C2) mRNA did not show significant changes. Using 2-D western analysis, untreated control rats were found to express only NR1(001 )whereas TNBS treated rats expressed NR1(001), NR1(011, )and NR1(111). Immunocytochemistry demonstrated NR1-N1 and NR1-C1 to be present in the myenteric plexus of TNBS treated rats. CONCLUSION: These results suggest a role for colonic myenteric plexus NMDA receptors in the development of neuronal plasticity and visceral hypersensitivity in the colon. Up-regulation of NMDA receptor subunits may reflect part of the basis for chronic visceral hypersensitivity in conditions such as post-infectious irritable bowel syndrome

Krt19\u3csup\u3e+\u3c/sup\u3e/Lgr5\u3csup\u3e-\u3c/sup\u3e Cells Are Radioresistant Cancer-Initiating Stem Cells in the Colon and Intestine

Epithelium of the colon and intestine are renewed every 3 days. In the intestine there are at least two principal stem cell pools. The first contains rapid cycling crypt-based columnar (CBC) Lgr5+ cells, and the second is composed of slower cycling Bmi1-expressing cells at the +4 position above the crypt base. In the colon, however, the identification of Lgr5- stem cell pools has proven more challenging. Here, we demonstrate that the intermediate filament keratin-19 (Krt19) marks long-lived, radiation-resistant cells above the crypt base that generate Lgr5+ CBCs in the colon and intestine. In colorectal cancer models, Krt19+ cancer-initiating cells are also radioresistant, while Lgr5+ stem cells are radiosensitive. Moreover, Lgr5+ stem cells are dispensable in both the normal and neoplastic colonic epithelium, as ablation of Lgr5+ stem cells results in their regeneration from Krt19-expressing cells. Thus, Krt19+ stem cells are a discrete target relevant for cancer therapy

Macrophage-derived extracellular vesicle-packaged WNTs rescue intestinal stem cells and enhance survival after radiation injury

WNT/β-catenin signalling is crucial for intestinal homoeostasis. The intestinal epithelium and stroma are the major source of WNT ligands but their origin and role in intestinal stem cell (ISC) and epithelial repair remains unknown. Macrophages are a major constituent of the intestinal stroma. Here, we analyse the role of macrophage-derived WNT in intestinal repair in mice by inhibiting their release using a macrophage-restricted ablation of Porcupine, a gene essential for WNT synthesis. Such Porcn-depleted mice have normal intestinal morphology but are hypersensitive to radiation injury in the intestine compared with wild-type (WT) littermates. Porcn-null mice are rescued from radiation lethality by treatment with WT but not Porcn-null bone marrow macrophage-conditioned medium (CM). Depletion of extracellular vesicles (EV) from the macrophage CM removes WNT function and its ability to rescue ISCs from radiation lethality. Therefore macrophage-derived EV-packaged WNTs are essential for regenerative response of intestine against radiation

Bile acid and inflammation activate gastric cardia stem cells in a mouse model of barrett-like metaplasia

Esophageal adenocarcinoma (EAC) arises from Barrett esophagus (BE), intestinal-like columnar metaplasia linked to reflux esophagitis. In a transgenic mouse model of BE, esophageal overexpression of interleukin-1β phenocopies human pathology with evolution of esophagitis, Barrett-like metaplasia and EAC. Histopathology and gene signatures closely resembled human BE, with upregulation of TFF2, Bmp4, Cdx2, Notch1, and IL-6. The development of BE and EAC was accelerated by exposure to bile acids and/or nitrosamines, and inhibited by IL-6 deficiency. Lgr5+ gastric cardia stem cells present in BE were able to lineage trace the early BE lesion. Our data suggest that BE and EAC arise from gastric progenitors due to a tumor-promoting IL-1β-IL-6 signaling cascade and Dll1-dependent Notch signaling. © 2012 Elsevier Inc

Dclk1 Defines Quiescent Pancreatic Progenitors that Promote Injury-Induced Regeneration and Tumorigenesis

The existence of adult pancreatic progenitor cells has been debated. While some favor the concept of facultative progenitors involved in homeostasis and repair, neither a location nor markers for such cells have been defined. Using genetic lineage tracing, we show that Doublecortin-like kinase-1 (Dclk1) labels a rare population of long-lived, quiescent pancreatic cells. In vitro, Dclk1+ cells proliferate readily and sustain pancreatic organoid growth. In vivo, Dclk1+ cells are necessary for pancreatic regeneration following injury and chronic inflammation. Accordingly, their loss has detrimental effects after cerulein-induced pancreatitis. Expression of mutant Kras in Dclk1+ cells does not affect their quiescence or longevity. However, experimental pancreatitis converts Kras mutant Dclk1+ cells into potent cancer-initiating cells. As a potential effector of Kras, Dclk1 contributes functionally to the pathogenesis of pancreatic cancer. Taken together, these observations indicate that Dclk1 marks quiescent pancreatic progenitors that are candidates for the origin of pancreatic cancer

CXCR4-expressing Mist1+ progenitors in the gastric antrum contribute to gastric cancer development

Mist1 was recently shown to identify a discrete population of stem cells within the isthmus of the oxyntic gland within the gastric corpus. Chief cells at the base of the gastric corpus also express Mist1. The relevance of Mist1 expression as a marker of specific cell populations within the antral glands of the distal stomach, however, is unknown. Using Mist1-CreERT mice, we revealed that Mist1+ antral cells, distinct from the Mist1+ population in the corpus, comprise long-lived progenitors that reside within the antral isthmus above Lgr5+ or CCK2R+ cells. Mist1+ antral progenitors can serve as an origin of antral tumors induced by loss of Apc or MNU treatment. Mist1+ antral progenitors, as well as other antral stem/progenitor population, express Cxcr4, and are located in close proximity to Cxcl12 (the Cxcr4 ligand)-expressing endothelium. During antral carcinogenesis, there is an expansion of Cxcr4+ epithelial cells as well as the Cxcl12+ perivascular niche. Deletion of Cxcl12 in endothelial cells or pharmacological blockade of Cxcr4 inhibits antral tumor growth. Cxcl12/Cxcr4 signaling may be a potential therapeutic target.Kosuke Sakitani, Yoku Hayakawa, Huan Deng, Hiroshi Ariyama, Hiroto Kinoshita ... Daniel L. Worthley... et al

Combining isotopic signatures of n(87Sr)/n(86Sr) and light stable elements (C, N, O, S) with multi-elemental profiling for the authentication of provenance of European cereal samples

The aim of this work (from the FP6 project TRACE) was to develop methods based on the use of geochemical markers for the authentication of the geographical origin of cereal samples in Europe (cf. EC regulations 2081/92 and 1898/06). For the first time, the potential usefulness of combining n(87Sr)/n(86Sr) and δ13C, δ15N, δ18O and δ34S isotopic signatures, alone or with key element concentrations ([Na], [K], [Ca], [Cu] and [Rb], progressively identified out of 31 sets of results), was investigated through multiple step multivariate statistics for more than 500 cereal samples collected over 2 years from 17 sampling sites across Europe representing an extensive range of geographical and environmental characteristics. From the classification categories compared (north/south; proximity to the Atlantic Ocean/to the Mediterranean Sea/to else; bed rock geologies) the first two were the most efficient (particularly with the ten variables selected together). In some instances element concentrations made a greater impact than the isotopic tracers. Validation of models included external prediction tests on 20% of the data randomly selected and, rarely done, a study on the robustness of these multivariate data treatments to uncertainties on measurement results. With the models tested it was possible to individualise 15 of the sampling sites