Biology subjects

Ramirez-Sanchez, A. D.

Publications and source records attributed to Ramirez-Sanchez, A. D..

3 recordsLinked to original sources

bioRxiv2026

Autologous biopsy-derived co-culture platform for interrogation of intestinal epithelial-T cell crosstalk

Interactions between intraepithelial lymphocytes (IELs) and the intestinal epithelium are central to mucosal homeostasis and disease. However, mechanistic in vitro studies describing their crosstalk in humans are limited by scarceness of primary material and insufficient knowledge about co-culture requirements. Here, we establish an autologous human duodenal IEL-organoid co-culture system encompassing expandable and bankable IEL and organoid protocols, with co-culture conditions that allow viability of both cell types. This system enables successive interrogation of lympho-epithelial interactions starting from minimal biopsy material. Under baseline conditions, CD45CD8CD103TCR{beta} IELs retain tissue-residency and effector features and induce an epithelial interferon response and chemokine production, without overt epithelial apoptosis. IL-15 and IL-21, essential cytokines involved in IEL-activation in intestinal enteropathies like celiac disease, increases granzyme B expression and interferon-{gamma} secretion but do not trigger epithelial cell death. However, enforcing IEL-epithelial contact using an anti-CD3-anti-Ep-CAM bispecific antibody induces epithelial apoptosis accompanied by increased tumor necrosis factor (TNF) and FAS-ligand (FASLG) secretion. These findings validate the platforms ability to resolve non-destructive and cytotoxic lympho-epithelial interaction and provide a tractable system for studying intestinal inflammation and immune-mediated epithelial cell death.

immunology↗

bioRxiv2024

Gene expression and eQTL analysis reflect the heterogeneity in the inflammatory status of the duodenal epithelial lining in coeliac disease

In coeliac disease (CeD), the epithelial lining (EL) of the small intestine is severely damaged through a complex auto-inflammatory response that results in intraepithelial lymphocytes (IELs) attacking epithelial cells (ECs). To better understand the changes occurring in the EL in CeD, including after initiation of a gluten-free diet, and the regulatory mechanisms that affect mucosal homeostasis, we investigated ECs and IELs in the CeD duodenal EL using RNA-seq and eQTL analysis on predicted cell types. The study included 82 duodenal biopsies from volunteers, grouped into controls (CTRL), gluten-free diet treated CeD (TCD) and untreated CeD (UCD). We identified 2,868 differential expressed genes, which clustered into four sets with specific functions related to CeD. Two sets, one upregulated for cell cycle function and one downregulated for digestion, transmembrane transport, and laminin pathways, defined three groups of samples based on inflammation status: non-inflamed, mild inflammation or severe inflammation. These inflammation states correlated with but were not specific to disease state. The remaining two sets of genes were enriched for immune, extracellular matrix, and barrier functions. These latter two sets allowed the classification of samples into their disease conditions: CTRL, TCD, and UCD. Finally, deconvoluting eQTL effects from ECs and immune cells in the EL identified 7 and 9 cell-type-mediated eQTL genes, respectively. In sum, we identified genes expressed in the duodenal EL whose expression might be used as biomarkers to assess CeD condition and its mucosal and immune status. HighlightsO_LIGene expression in epithelial lining in CeD patients reflects inflammation status C_LIO_LIThe transcriptome can classify epithelium as no, mild, or severe inflammation C_LIO_LICell cycle, absorption, and basal lamina genes are indicators of mucosal damage C_LIO_LIImmune and extracellular matrix genes distinguish untreated from treated cases C_LIO_LIPredicted-cell-type eQTLs pinpoint effects in immune and epithelial cells C_LI

immunology↗

bioRxiv2024

An iPSC-derived small intestine-on-chip with self-organizing epithelial, mesenchymal and neural cells

Human induced pluripotent stem cell (hiPSC)-derived intestinal organoids are valuable tools for researching developmental biology and personalized therapies, but their closed topology and relative immature state limits their applications. Here we use organ-on-chip technology to develop a hiPSC-derived intestinal barrier with apical and basolateral access in a more physiological in vitro microenvironment. To replicate growth factor gradients along the crypt- villus axis, we locally exposed the cells to expansion and differentiation media. In these conditions, intestinal epithelial cells self-organize into villus-like folds with physiological barrier integrity and myofibroblast and neural subtypes emerge and form a layer in the bottom channel underneath the epithelial tissue. The growth factor gradients efficiently balance dividing and mature cell types and induce an intestinal epithelial composition, including absorptive and secretory lineages, resembling the composition of the human adult small intestine. The result is a well-characterized hiPSC-derived intestine-on-chip system that can facilitate personalized studies on physiological processes and therapy development in the human small intestine.

cell biology↗