bioRxiv Science⌕ Search

Biology subjects

Koch-Laskowski, K. L.

Publications and source records attributed to Koch-Laskowski, K. L..

2 recordsLinked to original sources

Intestinal epithelial adaptations to vertical sleeve gastrectomy defined at single-cell resolution

The gut plays a key role in regulating metabolic health. Dietary factors disrupt intestinal physiology and contribute to obesity and diabetes, whereas bariatric procedures such as vertical sleeve gastrectomy (VSG) cause gut adaptations that induce robust metabolic improvements. However, our understanding of these adaptations at the cellular and molecular levels remains limited. In a validated murine model, we leverage single-cell transcriptomics to determine how VSG impacts different cell lineages of the small intestinal epithelium. We define cell type-specific genes and pathways that VSG rescues from high-fat diet perturbation and characterize additional rescue-independent changes brought about by VSG. We show that Paneth cells have increased expression of the gut peptide Reg3g after VSG. We also find that VSG restores pathways pertaining to mitochondrial respiration and cellular metabolism, especially within crypt-based cells. Overall, our study provides unprecedented molecular resolution of VSGs therapeutic effects on the gut epithelium.

genomics↗

Vertical Sleeve Gastrectomy Induces Enteroendocrine Cell Differentiation of Intestinal Stem Cells Through Farnesoid X Receptor Activation

Vertical sleeve gastrectomy (VSG) is one of several bariatric procedures that substantially improves glycemia and energy homeostasis. Increased secretion of multiple gut peptides has been hypothesized to be a critical contributor to VSGs potent effects to reduce body weight and improve glucose regulation. VSG results in an increase in the number of hormone-secreting enteroendocrine cells (EECs) in the intestinal epithelium, but whether this increase is via proliferation or differentiation of EECs and their subtypes remains unclear. Notably, the beneficial effects of VSG are lost in a mouse model lacking the bile acid nuclear receptor, farnesoid X receptor (FXR). FXR is a nuclear transcription factor that has been shown to regulate intestinal stem cell (ISC) function in cancer models, but whether it plays a role specifically in normal intestinal differentiation remains unknown. Therefore, we hypothesized that the VSG-induced increase in EECs is due to changes in intestinal differentiation driven by an increase in bile acid signaling through FXR. To test this, we performed VSG in mice that express eGFP in ISC/progenitor cells and performed RNAseq on GFP-positive cells sorted from the intestinal epithelia. We also assessed changes in EEC number (marked by GLP-1) in mouse intestinal organoids following treatment with bile acids and/or an FXR antagonist. RNA-seq revealed that FXR is expressed in ISCs and that VSG explicitly alters ISC expression of several genes that regulate intestinal secretory cell development, including EEC differentiation. Mouse intestinal organoids treated with bile acids increased GLP-1-positive cell numbers, whereas a potent FXR antagonist blocked this effect. Taken together, these data indicate that VSG drives ISC fate towards EEC differentiation through FXR signaling.

physiology↗