GM-CSF is effective in the treatment of DSS colitis in a mechanism involving the 440c(+) pDC population.

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PURPOSE: Preterm infants are susceptible to unique pathology due to their immaturity. Mouse models are commonly used to study immature intestinal disease including necrotizing enterocolitis (NEC). Current NEC models are performed at a variety of ages, but data directly comparing intestinal developmental stage equivalency between mice and humans are lacking. METHODS: Small intestines were harvested from C57B1/6 mice at 3–4-day intervals from birth to P28 (n=8 at each age). Preterm human small intestine samples representing 17–23 weeks of completed gestation were obtained from the University of Pittsburgh Health Sciences Tissue Bank, and at term gestation during reanastamoses after resection for NEC (n=4–7 at each age). Quantification of intestinal epithelial cell types and mRNA for marker genes were evaluated on both species. RESULTS: Overall, murine and human developmental trends over time are markedly similar. Murine intestine prior to P10 is most similar to human fetal intestine prior to viability. Murine intestine at P14 is most similar to human intestine at 22–23 weeks completed gestation, and P28 murine intestine is most similar to human term intestine. CONCLUSION: Use of C57BL/6J mice to model the human immature intestine is reasonable, but the age of mouse chosen is a critical factor in model development.

Background NOD2 single nucleotide polymorphisms have been associated with increased risk of ileal Crohn’s disease. This exploratory study was conducted to compare ileal mucosal gene expression in Crohn’s disease (CD) patients with and without NOD2 risk alleles. Methods Ileal samples were prospectively collected from eighteen non-smoking CD patients not treated with anti-TNFα biologics and nine non-smoking control patients without inflammatory bowel disease undergoing initial resection, and genotyped for the three major NOD2 risk alleles (Arg702Trp, Gly908Arg, Leu1007fs). Microarray analysis was performed in samples from four NOD2R (at least one risk allele) CD patients, four NOD2NR (no risk alleles) CD patients and four NOD2NR controls. Candidate genes selected by significance analysis of microarrays (SAM) were confirmed by quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) assays of all the samples. Results SAM detected upregulation of 18 genes in affected ileum in NOD2R compared to NOD2NR CD patients, including genes related to lymphocyte activation. SAM also detected altered ileal gene expression in unaffected NOD2NR ileal mucosal CD samples compared to NOD2NR control samples. QRT-PCR conducted on all the samples confirmed that increased CD3D expression in affected samples was associated with NOD2R status, and that increased MUC1, DUOX2, DMBT1 and decreased C4orf7 expression in unaffected samples was associated with CD, independent of NOD2 status. Conclusions The results support the concept that NOD2 risk alleles contribute to impaired regulation of inflammation in the ileum. Furthermore, altered ileal gene expression, independent of NOD2 status, is detected in the unaffected proximal margin of resected ileum from CD patients.

Summary Necrotizing enterocolitis (NEC) is a deadly intestinal inflammatory disorder that primarily affects premature infants and lacks adequate therapeutics. Interleukin (IL)-22 plays a critical role in gut barrier maintenance, promoting epithelial regeneration, and controlling intestinal inflammation in adult animal models. However, the importance of IL-22 signaling in neonates during NEC remains unknown. We investigated the role of IL-22 in the neonatal intestine under homeostatic and inflammatory conditions by using a mouse model of NEC. Our data reveal that Il22 expression in neonatal murine intestine is negligible until weaning, and both human and murine neonates lack IL-22 production during NEC. Mice deficient in IL-22 or lacking the IL-22 receptor in the intestine display a similar susceptibility to NEC, consistent with the lack of endogenous IL-22 during development. Strikingly, treatment with recombinant IL-22 during NEC substantially reduces inflammation and enhances epithelial regeneration. These findings may provide a new therapeutic strategy to attenuate NEC.

Rabbit smooth muscle cells (SMC) express types I and II scavenger receptors (ScR) that are up-regulated by platelet secretion products. In the current studies we investigated the effect of growth factors secreted by platelets on ScR activity in rabbit and human SMC. Platelet-derived growth factor (PDGF BB) and transforming growth factor ␤ 1 (TGF-␤ 1 ) at 10 ng/ml increased ScR activity in rabbit SMC (by approximately 4-and 2-fold, respectively) but not in human SMC. Epidermal growth factor (EGF) or insulin-like growth factor I (IGF-I) alone had little effect on SMC ScR activity. The growth factors had synergistic effects on ScR activity and on types I and II ScR mRNA expression. In rabbit SMC, PDGF BB, EGF, and TGF-␤ 1 together stimulated ScR activity 12-fold. In human SMC, EGF and TGF-␤ 1 , together with either IGF-I or PDGF BB, stimulated receptor activity approximately 7-fold. Growth factor-mediated induction of ScR activity in rabbit and human SMC was blocked by the tyrosine kinase inhibitor tyrphostin 47, whereas the induction of ScR activity in rabbit but not human SMC was blocked by the protein kinase C inhibitor MDL.29,152. Studies using neutralizing antibodies demonstrated that TGF-␤ 1 is the predominant factor in in vitro preparations of platelet secretory products which regulates ScR activity. The growth factors that act synergistically in regulating ScR activity in vitro are all present in atherosclerotic lesions, where they are produced by macrophages, endothelial cells, SMC, and platelets. The data suggest that these growth factors may regulate ScR activity in SMC in vivo and contribute to foam cell formation.

Previous genome-wide expression studies have highlighted distinct gene expression patterns in inflammatory bowel disease (IBD) compared to control samples, but the interpretation of these studies has been limited by sample heterogeneity with respect to disease phenotype, disease activity, and anatomic sites. To further improve molecular classification of inflammatory bowel disease phenotypes we focused on a single anatomic site, the disease unaffected proximal ileal margin of resected ileum, and three phenotypes that were unlikely to overlap: ileal Crohn's disease (ileal CD), ulcerative colitis (UC), and control patients without IBD. Whole human genome (Agilent) expression profiling was conducted on two independent sets of disease-unaffected ileal samples collected from the proximal margin of resected ileum. Set 1 (47 ileal CD, 27 UC, and 25 Control non-IBD patients) was used as the training set and Set 2 was subsequently collected as an independent test set (10 ileal CD, 10 UC, and 10 control non-IBD patients). We compared the 17 gene signatures selected by four different feature-selection methods to distinguish ileal CD phenotype with non-CD phenotype. The four methods yielded different but overlapping solutions that were highly discriminating. All four of these methods selected FOLH1 as a common feature. This gene is an established biomarker for prostate cancer, but has not previously been associated with Crohn's disease. Immunohistochemical staining confirmed increased expression of FOLH1 in the ileal epithelium. These results provide evidence for convergent molecular abnormalities in the macroscopically disease unaffected proximal margin of resected ileum from ileal CD subjects.