Gut homeostasis is a tightly regulated process requiring finely tuned complex interactions between different cell types, growth factors, or cytokines and their receptors. Previous work has implicated a role for IL-6 and mucosal immune cells in intestinal regeneration following injury and in promoting inflammation and cancer. We hypothesized that IL-6 signaling could also modulate crypt homeostasis. Using mouse in vitro crypt organoid and in vivo models, this study first demonstrated that exogenous IL-6 promoted crypt organoid proliferation and increased stem cell numbers through pSTAT3 activation in Paneth cells. Immunolabeling studies showed that the IL-6 receptor was restricted to the basal membrane of Paneth cells both in vitro and in vivo and that the crypt epithelium also expressed IL-6. Either a blocking Ab to the IL-6 receptor or a neutralizing Ab to IL-6 significantly reduced in vitro basal crypt organoid proliferation and budding, and in vivo significantly reduced the number of nuclei and the number of Lgr5EGFP-positive stem cells per crypt compared with IgG-treated mice, with the number of Paneth cells per crypt also significantly reduced. Functional studies demonstrated that IL-6–induced in vitro crypt organoid proliferation and crypt budding was abrogated by the Wnt inhibitor IWP2. This work demonstrates that autocrine IL-6 signaling in the gut epithelium regulates crypt homeostasis through the Paneth cells and the Wnt signaling pathway.

Inflammatory bowel diseases (IBDs) are chronic and relapsing immune disorders that result, or possibly originate, from epithelial barrier defects. Intestinal organoids are a new reliable tool to investigate epithelial response in models of chronic inflammation. We produced organoids from the ulcerative colitis murine model Winnie to explore if the chronic inflammatory features observed in the parental intestine were preserved by the organoids. Furthermore, we investigated if quercetin administration to in vitro cultured organoids could suppress LPS-induced inflammation in wild-type organoids (WT-organoids) and spontaneous inflammation in ulcerative colitis organoids (UC-organoids). Our data demonstrate that small intestinal organoids obtained from Winnie mice retain the chronic intestinal inflammatory features characteristic of the parental tissue. Quercetin administration was able to suppress inflammation both in UC-organoids and in LPS-treated WT-organoids. Altogether, our data demonstrate that UC-organoids are a reliable experimental system for investigating chronic intestinal inflammation and pharmacological responses.

Dendritic cells’ (DCs) ability to present antigens and initiate the adaptive immune response confers them a pivotal role in immunological defense against hostile infection and, at the same time, immunological tolerance towards harmless components of the microbiota. Food products can modulate the inflammatory status of intestinal DCs. Among nutritionally-derived products, we investigated the ability of quercetin to suppress inflammatory cytokines secretion, antigen presentation, and DCs migration towards the draining lymph nodes. We recently identified the Slpi expression as a crucial checkpoint required for the quercetin-induced inflammatory suppression. Here we demonstrate that Slpi-KO DCs secrete a unique panel of cytokines and chemokines following quercetin exposure. In vivo, quercetin-enriched food is able to induce Slpi expression in the ileum, while little effects are detectable in the duodenum. Furthermore, Slpi expressing cells are more frequent at the tip compared to the base of the intestinal villi, suggesting that quercetin exposure could be more efficient for DCs projecting periscopes in the intestinal lumen. These data suggest that quercetin-enriched nutritional regimes may be efficient for suppressing inflammatory syndromes affecting the ileo-colonic tract.

Tunneling nanotubes (TNTs) are thin cytoplasmic extensions involved in long-distance intercellular communication and can transport intracellular organelles and signalling molecules. In cancer cells, TNT formation contributes to cell survival, chemoresistance, and malignancy. However, the molecular mechanisms underlying TNT formation are not well defined, especially in different cancers. TNTs are present in non-small cell lung cancer (NSCLC) patients with adenocarcinoma. In NSCLC, hepatocyte growth factor (HGF) and its receptor, c-Met, are mutationally upregulated, causing increased cancer cell growth, survival, and invasion. This study identifies c-Met, β1-integrin, and paxillin as novel components of TNTs in A549 lung adenocarcinoma cells, with paxillin localised at the protrusion site of TNTs. The HGF-induced TNTs in our study demonstrate the ability to transport lipid vesicles and mitochondria. HGF-induced TNT formation is mediated by c-Met and β1-integrin in conjunction with paxillin, followed by downstream activation of MAPK and PI3K pathways and the Arp2/3 complex. These findings demonstrate a potential novel approach to inhibit TNT formation through targeting HGF/c-Met receptor and β1-integrin signalling interactions, which has implications for multi-drug targeting in NSCLC.

Background: The colonic epithelium is the most rapidly renewing tissue in the body and is organized into a single cell layer of invaginations called crypts. Crypt renewal occurs through Lgr5 + gut stem cells situated at the crypt base, which divide, produce daughter cells that proliferate, migrate, differentiate into all the cells required for normal gut function, and are finally shed into the crypt lumen. In health, this rapid renewal helps maintain barrier function next to the hostile gut microbial luminal environment. Inflammation results in an influx of immune cells including inflammatory M1 macrophages into the gut mucosa next to the crypt epithelium, but the direct effect of macrophages on crypt regeneration and renewal are poorly understood. Methods: Using an in vitro macrophage-crypt coculture model, we show that homeostatic M2 macrophages and inflammatory M1 macrophages confer different effects on the crypt epithelium. Results: Both M1 and M2 increase crypt cell proliferation, with M2 macrophages requiring physical contact with the crypt epithelium, whereas M1 macrophages exert their effect through a secreted factor. Only M1 macrophages reduce goblet and Tuft cell numbers and increase Lgr5 + crypt stem cell numbers, all dependent on physical contact with the crypt epithelium. Further studies showed that M1 macrophages increase the Wnt signaling pathways cyclin D1 and LEF1 through physical contact rather than a secreted factor. Conclusions: These findings highlight the importance of understanding distinct cellular interactions and direct dialogue between cells and increase our understanding of the contribution of different immune cell subtypes on crypt cell biology during inflammation.

A library of ferrocenyl β‐diketonate compounds with varying degrees of aromatic functionality have been synthesized and fully characterized. This includes cyclic voltammetry and the analysis of four new structures by single crystal X‐ray diffraction. The compounds cytotoxic potential has been determined by MTT screening against pancreatic carcinoma (MIA PaCa‐2), ovarian adenocarcinoma (A2780), breast adenocarcinomas (MDA‐MB‐231 and MCF‐7) and normal epithelial retinal (ARPE‐19). The compounds show a general trend, where increasing the number of aromatic rings in the molecule yields an increase in cytotoxicity and follows the trend anthracenyl>naphthyl>phenyl>methyl. The compounds are particularly sensitive to the triple negative cancer cell line MDA‐MB‐231, and the potential modes of action have been studied by production of reactive oxygen species using fluorescence microscopy and cell morphology using Scanning Electron Microscopy. All assays highlight the ferrocenyl β‐diketonate with an anthracenyl substituent to be the lead compound in this library. The decomposition of this compound was also observed within cells, yielding a cytotoxic fluorescent molecule, which has been visualized by confocal microscopy.