Stromal regulation of the intestinal epithelium – a novel role for the OGF/OGFR axis

Principle Investigator

Scientific interest within the context of the graduate college

The epithelium of the gastrointestinal tract is a single cell layer organized into villi and crypts, which separates microbiota and host. Stem cells in the crypts constantly generate epithelial progenitors that differentiate and migrate toward the villus tip, where they are shed into the lumen. While some of these processes are epithelial-intrinsic, coordinated interactions with underlying stromal cells are essential for tissue morphogenesis, stem cell maintenance, epithelial differentiation and spatial zonation along the crypt–villus axis. Importantly, disruption of this communication not only impairs local tissue integrity but also drives systemic inflammation, metabolic dysfunction, and cancer risk. Understanding these interactions will provide key insights into the mechanisms linking tissue-specific processes to overall organismal health and disease.

In our lab, we specifically investigate how intestinal stromal and epithelial cells communicate to maintain tissue homeostasis. Recently, we identified the transcription factor c-Maf as a key regulator of enterocyte differentiation controlled by stromal Noggin/BMP signals, linking spatial patterning along the villus axis to nutrient absorption and epithelial function. Disruption of this pathway impairs enterocyte maturation and alters immune and microbial homeostasis. Our current work focuses on the molecular pathways, cellular interactions, and spatial organization that coordinate stromal–epithelial crosstalk within the gut microenvironment. By integrating cell biology, genomics, and advanced imaging approaches, we aim to define how these interactions are perturbed in intestinal disease and to identify strategies to restore intestinal function.

Project description

In the healthy gut, the delicate balance between intestinal epithelial cell (IEC) proliferation, differentiation and apoptosis maintains barrier integrity, however, chronic inflammation disrupts this homeostasis. While stromal cells are known to regulate IEC fate via niche-derived signals, the specific molecular mediators governing these interactions remain incompletely defined. Our preliminary work identifies the opioid growth factor (OGF) and its receptor (OGFR) pathway as a previously unrecognized signalling axis between intestinal stromal cells and IECs, that is markedly upregulated during gut inflammation. Based on these findings, this project aims to comprehensively characterize this crosstalk, its regulation and functional relevance for IEC and gut homeostasis and inflammation.

To define the signals that regulate intestinal OGF/OGFR expression. While IECs are known to express OGFR and specific stromal cell populations produce OGF, the upstream signals controlling their expression remain poorly understood. Based on preliminary data, we hypothesize that homeostatic cues, including microbial- and immune cell-derived signals, regulate OGF/OGFR expression under steady-state conditions. Furthermore, our findings of increased OGF/OGFR expression during intestinal inflammation suggest that pro-inflammatory cytokines also contribute to their regulation. The objective of this project is to systematically identify and characterize the signals governing OGF/OGFR expression in the intestine.

Aim 1: Which signals regulate OGFR expression in intestinal IECs? 3D intestinal organoids (“gut in a dish”) are generated from primary mouse intestinal epithelial cells (IECs) using cell culture techniques. Cytokine stimulation experiments are then performed with these 3D intestinal organoids. Following stimulation, OGFR expression in the organoids is analyzed by quantitative PCR (qPCR). In addition, primary mouse IECs are isolated from different transgenic mouse strains (e.g., microbiota-deficient or immunodeficient mice) using fluorescence-activated cell sorting (FACS). Finally, endogenous OGFR expression in the FACS-sorted IECs is measured by qPCR.

Aim 2: Which signals regulate OGF expression in intestinal stromal cells? Primary mouse intestinal stromal cells are isolated using fluorescence-activated cell sorting (FACS). These cells are then cultured under appropriate cell culture conditions. Cytokine stimulation experiments are subsequently performed with the mouse intestinal stromal cells. Following stimulation, OGF expression in the stromal cells is analyzed by quantitative PCR (qPCR). In addition, gut tissue samples are prepared for immunofluorescence (IF) microscopy, including embedding, sectioning, and mounting. Finally, endogenous OGF expression is analyzed by IF microscopy in OGF reporter mice.

This project will combine different in vitro and in vivo approaches to define the signals that regulate OGFR and OGF expression in intestinal IECs and stromal cells, respectively. Key techniques will include isolation of primary mouse intestinal IECs and stromal cells, cell culture, 3D intestinal organoids, flow cytometry and flow cytometry-mediated cell sorting, tissue embedding, cryosectioning, staining, immunofluorescence microscopy and qPCR.

Application details

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