Reg IV is differently expressed in enteroendocrine cells of human small intestine and colon

REG4 promotes the proliferation and anti-apoptosis of cancer

Regenerating islet-derived 4 (REG4) gene was discovered by high-throughput sequencing of ulcerative colitis cDNA libraries. REG4 is involved in infection and inflammation by enhancing macrophage polarization to M2, via activation of epidermal growth factor receptor (EGFR)/Akt/cAMP-responsive element binding and the killing inflammatory Escherichia coli, and closely linked to tumorigenesis. Its expression was transcriptionally activated by caudal type homeobox 2, GATA binding protein 6, GLI family zinc finger 1, SRY-box transcription factor 9, CD44 intracytoplasmic domain, activating transcription factor 2, and specificity protein 1, and translationally activated by miR-24. REG4 can interact with transmembrane CD44, G protein-coupled receptor 37, mannan and heparin on cancer cells. Its overexpression was observed in gastric, colorectal, pancreatic, gallbladder, ovarian and urothelial cancers, and is closely linked to their aggressive behaviors and a poor prognosis. Additionally, REG4 expression and recombinant REG4 aggravated such cellular phenotypes as tumorigenesis, proliferation, anti-apoptosis, chemoradioresistance, migration, invasion, peritoneal dissemination, tumor growth, and cancer stemness via EGFR/Akt/activator protein-1 and Akt/glycogen synthase kinase three β/β-catenin/transcription factor 4 pathways. Sorted REG4-positive deep crypt secretory cells promote organoid formation of single Lgr5 (+) colon stem cells by Notch inhibition and Wnt activation. Histologically, REG4 protein is specifically expressed in neuroendocrine tumors and signet ring cell carcinomas of the gastrointestinal tract, pancreas, ovary, and lung. It might support the histogenesis of gastric intestinal–metaplasia–globoid dysplasia–signet ring cell carcinoma. In this review, we summarized the structure, biological functions, and effects of REG4 on inflammation and cancer. We conclude that REG4 may be employed as a biomarker of tumorigenesis, subsequent progression and poor prognosis of cancer, and may be a useful target for gene therapy.

High-Throughput Identification of the Plasma Proteomic Signature of Inflammatory Bowel Disease

BACKGROUND

The molecular aetiology of inflammatory bowel disease [IBD] and its two subtypes, ulcerative colitis [UC] and Crohn's disease [CD], have been carefully investigated at genome and transcriptome levels. Recent advances in high-throughput proteome quantification has enabled comprehensive large-scale plasma proteomics studies of IBD.

METHODS

The study used two cohorts: [1] The CERTIFI-cohort: 42 samples from the CERTIFI trial of anti-TNFα-refractory CD patients; [2] the PROgECT-UNITI-HCs cohort: 46 UC samples of the PROgECT study, 84 CD samples of the UNITI I and UNITI II studies, and 72 healthy controls recruited in Mount Sinai Hospital, New York, USA. The plasma proteome for these two cohorts was quantified using high-throughput platforms.

RESULTS

For the PROgECT-UNITI-HCs cohort, we measured a total of 1310 proteins. Of these, 493 proteins showed different plasma levels in IBD patients to the plasma levels in controls at 10% false discovery rate [FDR], among which 11 proteins had a fold change greater than 2. The proteins upregulated in IBD were associated with immunity functionality, whereas the proteins downregulated in IBD were associated with nutrition and metabolism. The proteomic profiles were very similar between UC and CD. In the CERTIFI cohort, 1014 proteins were measured, and it was found that the plasma protein level had little correlation with the blood or intestine transcriptomes.

CONCLUSIONS

We report the largest proteomics study to date on IBD and controls. A large proportion of plasma proteins are altered in IBD, which provides insights into the disease aetiology and indicates a potential for biomarker discovery.

Unique Gene Expression Signatures in the Intestinal Mucosa and Organoids Derived from Germ-Free and Monoassociated Mice

Commensal microbiota contribute to gut homeostasis by inducing transcription of mucosal genes. Analysis of the impact of various microbiota on intestinal tissue provides an important insight into the function of this organ. We used cDNA microarrays to determine the gene expression signature of mucosa isolated from the small intestine and colon of germ-free (GF) mice and animals monoassociated with two E. coli strains. The results were compared to the expression data obtained in conventionally reared (CR) mice. In addition, we analyzed gene expression in colon organoids derived from CR, GF, and monoassociated animals. The analysis revealed that the complete absence of intestinal microbiota mainly affected the mucosal immune system, which was not restored upon monoassociation. The most important expression changes observed in the colon mucosa indicated alterations in adipose tissue and lipid metabolism. In the comparison of differentially expressed genes in the mucosa or organoids obtained from GF and CR mice, only six genes were common for both types of samples. The results show that the increased expression of the angiopoietin-like 4 (Angptl4) gene encoding a secreted regulator of lipid metabolism indicates the GF status.

Glycosylation-related gene expression in HT29-MTX-E12 cells upon infection by Helicobacter pylori

AIM

To identify glycosylation-related genes in the HT29 derivative cell line, HT29-MTX-E12, showing differential expression on infection with Helicobacter pylori (H. pylori).

METHODS

Polarised HT29-MTX-E12 cells were infected for 24 h with H. pylori strain 26695. After infection RNA was isolated from both infected and non-infected host cells. Sufficient infections were carried out to provide triplicate samples for microarray analysis and for qRT-PCR analysis. RNA was isolated and hybridised to Affymetrix arrays. Analysis of microarray data identified genes significantly differentially expressed upon infection. Genes were grouped into gene ontology functional categories. Selected genes associated with host glycan structure (glycosyltransferases, hydrolases, lectins, mucins) were validated by real-time qRT-PCR analysis.

RESULTS

Infection of host cells was confirmed by the isolation of live bacteria after 24 h incubation and by PCR amplification of bacteria-specific genes from the host cell RNA. H. pylori do not survive incubation under the adopted culture conditions unless they associate with the adherent mucus layer of the host cell. Microarray analysis identified a total of 276 genes that were significantly differentially expressed (P < 0.05) upon H. pylori infection and where the fold change in expression was greater than 2. Six of these genes are involved in glycosylation-related processes. Real-time qRT-PCR demonstrated significant downregulation (1.8-fold, P < 0.05) of the mucin MUC20. REG4 was heavily expressed and significantly downregulated (3.1-fold, P < 0.05) upon infection. Gene ontology analysis was consistent with previous studies on H. pylori infection.

CONCLUSION

Gene expression data suggest that infection with H. pylori causes a decrease in glycan synthesis, resulting in shorter and simpler glycan structures.