Summary Inflammation promotes regeneration of injured tissues through poorly understood mechanisms, some of which involve interleukin (IL)-6 family members whose expression is elevated in many diseases, including inflammatory bowel diseases (IBD) and colorectal cancer (CRC). We show that gp130, a co-receptor for IL-6 cytokines, triggers activation of YAP and Notch, transcriptional regulators that control tissue growth and regeneration, independently of the classic gp130 effector STAT3. Through YAP and Notch, intestinal gp130 signaling stimulates epithelial cell proliferation, causes aberrant differentiation and confers resistance to mucosal erosion. gp130 associates with the related tyrosine kinases Src and Yes, which are activated upon receptor engagement to phosphorylate YAP and induce its stabilization and nuclear translocation. This signaling module is strongly activated upon mucosal injury to promote healing and maintain barrier function.

A mosaic of cross-phylum chemical interactions occurs between all metazoans and their microbiomes. A number of molecular families known to be produced by the microbiome have a profound impact on the balance between health and disease 1-9. Considering the diversity of the human microbiome, numbering over 40,000 operational taxonomic units 10 , the impact of the microbiome on the chemistry of an entire animal remains underexplored. In this study, mass spectrometry informatics and data visualization approaches 11-13 were used to provide an assessment of the impacts of the microbiome on the chemistry of an entire mammal by comparing metabolomics data from germ-free (GF) and specific pathogen Reprints and/or permissions can be provided by R. Quinn or P.C. Dorrestein.

VDZ is a safe and effective treatment option for moderate-severe CD in routine practice. Clinical remission and deep remission (clinical remission and mucosal healing) can be achieved in 1/3 of individuals, and a minority of individuals require discontinuation of therapy due to adverse events.

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During an immune response to microbial infection, CD8+ T cells give rise to distinct classes of cellular progeny that coordinately mediate clearance of the pathogen and provide long-lasting protection against reinfection, including a subset of noncirculating tissue-resident memory (TRM) cells that mediate potent protection within nonlymphoid tissues. Here, we used single-cell RNA sequencing to examine the gene expression patterns of individual CD8+ T cells in the spleen and small intestine intraepithelial lymphocyte (siIEL) compartment throughout the course of their differentiation in response to viral infection. These analyses revealed previously unknown transcriptional heterogeneity within the siIEL CD8+ T cell population at several stages of differentiation, representing functionally distinct TRM cell subsets and a subset of TRM cell precursors within the tissue early in infection. Together, these findings may inform strategies to optimize CD8+ T cell responses to protect against microbial infection and cancer.

Inflammatory bowel disease (IBD) encompasses a spectrum of gastrointestinal disorders driven by dysregulated immune responses against gut microbiota. We integrated single-cell RNA and antigen receptor sequencing to elucidate key components, cellular states, and clonal relationships of the peripheral and gastrointestinal mucosal immune systems in health and ulcerative colitis (UC). UC was associated with an increase in IgG1+ plasma cells in colonic tissue, increased colonic regulatory T cells characterized by elevated expression of the transcription factor ZEB2, and an enrichment of a γδ T cell subset in the peripheral blood. Moreover, we observed heterogeneity in CD8+ tissue-resident memory T (TRM) cells in colonic tissue, with four transcriptionally distinct states of differentiation observed across health and disease. In the setting of UC, there was a marked shift of clonally related CD8+ TRM cells toward an inflammatory state, mediated, in part, by increased expression of the T-box transcription factor Eomesodermin. Together, these results provide a detailed atlas of transcriptional changes occurring in adaptive immune cells in the context of UC and suggest a role for CD8+ TRM cells in IBD.

Background and Aims We sought to analyze whether response to a second-line biologic varies depending on the reason for discontinuation of the primary anti-TNF agent (primary non-response [PNR], secondary loss of response [LOR] after initial response, or intolerance), through a systematic review and meta-analysis. Methods Through a systematic search through May 31, 2017, we identified eight randomized controlled trials [RCTs] of biologics in patients with IBD with prior exposure to anti-TNF agents, that stratified response to second-line therapy by reason for discontinuing primary anti-TNF therapy [PNR vs. LOR vs. intolerance]. We estimated relative risk [RR] (and 95% confidence interval [CI]) of achieving clinical remission in patients with PNR as compared with patients with LOR, and intolerance, through random effects meta-analysis. Results As compared with patients who discontinued prior anti-TNF due to intolerance, patients with prior PNR were 24% less likely to achieve remission with second-line biologics (RR,0.76 [0.61–0.96]). As compared with patients who discontinued prior anti-TNF due to LOR, patients with prior PNR were 27% less likely to achieve remission with induction therapy with second-line biologics (RR,0.73 [0.56–0.97]), particularly to ustekinumab (RR,0.64 [0.52–0.80]). There was no difference in response to vedolizumab in patients with prior PNR or LOR to anti-TNF agents (RR,1.16 [0.85–1.58]). Conclusion Patients with PNR to anti-TNF agents are less likely to respond to second-line non-TNF biologics, as compared with patients who discontinued therapy due to secondary LOR or intolerance. This may be attributed to underlying pharmacokinetics and pharmacodynamics of anti-TNF agents in patients with PNR.

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