Background Inflammatory bowel diseases (IBDs) are characterised by dysbiosis and a leaky gut. The NADPH oxidase dual oxidase 2 (DUOX2) is upregulated in patients with IBD, yet its role in driving the disease remains unclear. Objective We interrogated the functional consequences of epithelial DUOX2 activity for the host and microbiome. Design DUOX2 function was studied in mice with epithelial-specific DUOX2 overactivation (vTLR4), inactivation (vTLR4 DUOXA IEC-KO) and wild-type controls. We assessed the effect of dysbiosis on DUOX2 signalling and intestinal permeability (FITC-dextran, serum zonulin, bacterial translocation) with germ-free (GF) mice engrafted with IBD or healthy microbiota. RNA sequencing of colonic mucosa and microbiota and faecal metabolomics were used to characterise the host–microbe interface. Mechanistic studies were conducted in mouse colonoids, IBD biopsies and patient serum samples. Results DUOX2 activity increased permeability and bacterial translocation and induced subclinical inflammation in vTLR4 mice. GF vTLR4 mice had increased DUOX2 activity and permeability but no subclinical inflammation. In patients with IBD, DUOX2 expression was positively associated with plasma zonulin levels and negatively associated with ZO-1 expression. Engraftment of GF mice with IBD stool increased DUOX2 activity and triggered low-grade inflammation and permeability defects in mice. DUOX2 activity functionally altered the microbiome, reduced butyrate metabolism and promoted proinflammatory and pro-oncogenic bacterial metabolites. Butyrate and histone deacetylase (HDAC) inhibitors blocked DUOX2 activation and reversed its effects. Conclusions Elevated DUOX2 signalling contributes to epithelial barrier dysfunction, microbiome alterations and subclinical inflammation. Butyrate and HDAC inhibitors reversed these effects, indicating that DUOX2 may be a therapeutic target in IBD.

The current approach to minimize transplant-associated complications, including graft-versus-host disease (GVHD) includes long-term pharmacological immune suppression frequently accompanied by unwanted side effects. Advances in targeted immunotherapies regulating alloantigen responses in the recipient continue to reduce the need for pan-immunosuppression. Here, in vivo targeting of the tumor necrosis factor superfamily receptor TNFRSF25 (also known as DR3) and the high-affinity interleukin-2 (IL-2) receptor with a TL1A-immunoglobulin (TL1A-Ig) fusion protein and low-dose IL-2, respectively, was used to pretreat recipient mice before allogeneic hematopoietic stem cell transplantation (aHSCT). Pretreatment induced regulatory T cell (Treg) expansion persisting 1 to 2 weeks after HSCT, leading to diminished GVHD and improved transplant outcomes. Expansion was accompanied by an increase in the frequency of stable and active Tregs, creating a suppressive tissue environment in the colon, liver, and eye. Importantly, pretreatment supported epithelial cell function/integrity, a diverse microbiome including reduction of pathologic bacteria outgrowth, and promotion of butyrate producing bacteria, while maintaining physiologic levels of obligate/facultative anaerobes. Notably, using a sphingosine 1-phosphate receptor agonist to sequester T cells in lymphoid tissues, it was found that the increased tissue Treg frequency included resident CD69+CD103+FoxP3+ hepatic Tregs. In contrast to infusion of donor Tregs, the strategy developed here resulted in the presence of immunosuppressive target tissue environments in the recipient before the receipt of donor allogeneic-reactive T cells and successful perseveration of graft-versus-leukemia responses. We posit strategies that circumvent the need of producing large numbers of ex vivo manipulated Tregs may be accomplished through in vivo recipient Treg expansion, providing translational approaches to improve aHSCT outcomes.

Background/Objectives: Oxidized low-density lipoprotein (ox-LDL) is a proinflammatory particle associated with various diseases and affects cell proliferation and viability in multiple cell types. However, its impact on intestinal epithelial cells remains underexplored. This study investigates the effect of ox-LDL on colonic epithelial cell proliferation and viability, as well as the underlying mechanisms involved. Methods: The expression levels of ox-LDL receptors in human colonoids were analyzed at baseline and in response to proinflammatory signals by qRT-PCR. The effect of ox-LDL on organoid proliferation was analyzed using morphometric measurements, viability assays, and the incorporation of a thymidine analog into DNA. The generation of reactive oxygen species (ROS) was determined by Amplex Red assays. Additionally, ox-LDL-induced ROS-dependent organoid proliferation was studied by exposing colonoids to an antioxidant or ROS inhibitors. Results: Colonic epithelial cells express ox-LDL receptors. Ox-LDL significantly induces the proliferation of colonic epithelial cells, which are dependent on ROS generation. Notably, ROS scavengers and NADPH inhibitors reduced ox-LDL-induced proliferation, highlighting the crucial role of oxidative stress in this process. Conclusions: This study demonstrates for the first time that ox-LDL stimulates CEC proliferation mediated by ROS production and validates that the colonic organoid model enables the analysis of potential pharmacological strategies for intestinal diseases characterized by oxidative stress and inflammation.

BioStudies – one package for all the data supporting a study

BioStudies – one package for all the data supporting a study

BioStudies – one package for all the data supporting a study