Gli1 Deletion Prevents Helicobacter-Induced Gastric Metaplasia and Expansion of Myeloid Cell Subsets

Abstract

Chronic inflammation in the stomach induces metaplasia, the pre-cancerous lesion that precedes inflammation-driven neoplastic transformation. While Hedgehog signaling contributes to the initiation of some cancers, its role in gastric transformation remains poorly defined. We found that Helicobacter-infected C57BL/6 mice develop extensive mucous cell metaplasia at 6 month but not at 2 months post-infection. Gastric metaplasia coincided with the appearance of CD45+MHCII+CD11b+CD11c+ myeloid cells that were normally not present in the chronic gastritis at 2 months. The myeloid regulatory gene Schlafen-4 was identified in a microarray analysis comparing infected WT versus Gli1 null mice and was expressed in the CD11b+CD11c+ myeloid population. Moreover this same population expressed IL-1β and TNFα pro-inflammatory cytokines. By 6 months, the mucous neck cell metaplasia (SPEM) expressed IL-6, phosphorylated STAT3 and the proliferative marker Ki67. Expression was not observed in Gli1 mutant mice consistent with the requirement of Gli1 to induce this pre-neoplastic phenotype. Ectopic Shh ligand expression alone was not sufficient to induce SPEM, but with Helicobacter infection synergistically increased the histologic severity observed with the inflammation. Therefore Hedgehog signaling is required, but is not sufficient to generate pre-neoplastic changes during chronic gastritis. Gli1-dependent myeloid cell differentiation plays a pivotal role in the appearance of myeloid cell subtypes ostensibly required for SPEM development. Moreover, it suggests that therapies capable of targeting this phenotypic switch might prevent progression to metaplasia, the pre-neoplastic change that develops prior to dysplasia and gastric cancer, which also occurs in other epithelial-derived neoplasias initiated by chronic inflammation.

The Transcription Factor GLI1 Modulates the Inflammatory Response during Pancreatic Tissue Remodeling

“…Specifically, mice hemizygous for Gli1 are more susceptible to intestinal inflammation and chemical-induced injury (42). Gli1 ϩ/Ϫ mice are also less susceptible to inflammation-induced metaplasia upon Helicobacter pylori infection (43). In humans, a variant of Gli1 with reduced transcriptional function confers higher susceptibility to irritable bowel disease mediated by an altered myeloid response (42).…”

Tryptophan Catabolism Restricts IFN-γ–Expressing Neutrophils and Clostridium difficile Immunopathology

“…Cecal tissue was divided intro different groups: 1) For mass spectrometric analysis of kynurenine, cecal tissue was snap frozen in liquid nitrogen; 2) for RNA tissue samples were homogenized in TRIzol (Invitrogen, Carlsbad, CA) and cleaned up using the RNEasy Microkit (Qiagen, Valencia, CA) as previously described (21); 3) for histology, the cecum was cut longitudinally and the section incubated in formalin for 2 days followed by 70% ethanol, processing and paraffin embedding; 4) for frozen blocks, longitudinal cecal tissue was frozen in OCT compound (Fisher Scientific, Houston, TX) on dry ice (22); 5) for DNA samples to measure toxin DNA, cecal tissue was snap frozen in liquid nitrogen and extracted using the DNEasy Blood and Tissue Kit (Qiagen). All tissue segments were collected from equivalent positions within the ceca of different mice.…”

“…Immunofluorescence on frozen sections was performed as previously described (21). The following antibodies were used: polyclonal goat anti-mouse IDO1 (I-17 Cat # sc-25121, or M-20 Cat # sc-25123, Santa Cruz Biotechnology, Santa Cruz, CA); FITC conjugated monoclonal hamster anti CD11c (clone N418, Cat # 117306, BioLegend, San Diego, CA); monoclonal rabbit anti E-Cadherin (clone 24E10, Cat #3195, Cell Signaling, Boston, MA);FITC conjugated monoclonal mouse anti MPO (clone 2D4, Cat #ab90812, Abcam, Cambridge, MA); Alexa Fluor 647 conjugated (far red) monoclonal rat anti IFNγ (clone XMG1.2, Cat #505816, BioLegend).…”

Overexpressed KDM5B is associated with the progression of glioma and promotes glioma cell growth via downregulating p21

“…Numerous studies indicate that the development and progression of glioma arises via miss-regulation of many related genes such as p53, p21, Akt, Gli1, and PTEN [1][2][3][4][5][6]. However, the regulatory mechanisms remain poorly understood.…”