Charlier, B. | Search bioRxiv

bioRxiv2024

xIV-LDDMM Toolkit: A Suite of Image-Varifold Based Technologies for Representing and Mapping 3D Imaging and Spatial-omics Data Simultaneously Across Scales

Advancements in imaging and molecular techniques enable the collection of subcellular-scale data. Diversity in measured features, resolution, and physical scope of capture across technologies and experimental protocols pose numerous challenges to integrating data with reference coordinate systems and across scales. This paper describes a collection of technologies that we have developed for mapping data across scales and modalities, such as genes to tissues, specifically in a 3D setting. Our collection of technologies include (i) an explicit censored data representation for the partial matching problem mapping whole brains to subsampled subvolumes, (ii) a multi, scale-space optimization technology for generating resampling grids optimized to represent spatial geometry at fixed complexities, and (iii) mutual-information based functional feature selection. We integrate these technologies with our cross-modality mapping algorithm through the use of image-varifold measure norms to represent universally data across scales and imaging modalities. Collectively, these methods afford efficient representations of peta-scale imagery providing the algorithms for mapping from the nano to millimeter scales, which we term cross-modality image-varifold LDDMM (xIV-LDDMM).

bioengineering↗

bioRxiv2024

A microbial derived bile acid acts as GPBAR1 agonist and RORγt inverse agonist and reverses inflammation in inflammatory bowel disease

The interplay between the dysbiotic microbiota and bile acids is a critical determinant for development of a dysregulated immune system in inflammatory bowel disease (IBD). Here we have investigated the fecal bile acid metabolome, gut microbiota composition, and immune responses in IBD patients and murine models of colitis and found that IBD associates with an elevated excretion of primary bile acids while secondary, allo- and oxo- bile acids were reduced in both human and mice models of IBD. These changes correlated with the disease severity, mucosal expression of pro-inflammatory cytokines and chemokines, and reduced inflow of anti-inflammatory macrophages and Treg in the gut. Analysis of bile acids metabolome in the feces allowed the identification of five bile acids: 3-oxo-DCA, 3-oxo-LCA, allo-LCA, iso-allo-LCA and 3-oxo-UDCA, whose excretion was selectively decreased in IBD patients and diseased mice. By transactivation assay and docking calculations all five bile acids were shown to act as GPBAR1 agonists and ROR{gamma}t inverse agonists, skewing Th17/Treg ratio and macrophage polarization toward an M2 phenotype. In a murine model of colitis, administration of 3-oxo-DCA suffices to reverse colitis development and intestinal dysbiosis in a GPBAR1-dependent manner. In vivo administration of 3-oxo-DCA to colitic mice also reserves disease severity and ROR{gamma}t activation induced by a ROR{gamma}t agonist and IL-23, a Th17 inducing cytokine. These results demonstrated intestinal excretion of 3-oxoDCA, a dual GPBAR1 agonist and ROR{gamma}t inverse agonist, is reduced in IBD and models of colitis and its restitution protects against colitis development, highlighting a potential role for this agent in IBD management.

immunology↗