A biosensor platform for scalable and live detection of PYY hormone production from enteroendocrine cells with single-event resolution.

Peptide YY (PYY) comprises the secretory repertoire of enteroendocrine L-cells alongside glucagon-like peptide-1 (GLP-1), and positively modulates postprandial satiety, digestion mechanics, and regeneration of the intestinal epithelium. While immortalized GLP-1-secreting human L-cell models support pre-clinical drug discovery, comparable human lines that robustly secrete PYY are lacking, hindering mechanistic studies of its release. We present a biosensor for detection of PYY production and secretion from human enteroendocrine cells in vitro. Guided by in silico structural prediction, we engineer a superecliptic phluorin (SEP)-tagged PYY, SEP-PYY, that engages native hormone processing machinery and is responsive to canonical nutrient stimuli when expressed in a human enteroendocrine-like cell line, NCI-H716. SEP-PYY production and secretion can be measured by flow cytometry and spectrofluorometric plate readouts, respectively, methods with superior time- and cost-efficacy to current hormone detection methods. Leveraging the pH sensitivity of SEP, we use this biosensor in the detection of single-event hormone exocytosis by total internal reflection microscopy. Finally, we demonstrate the application of our platform in screening ligands of metabolite-sensing Gprotein-coupled receptors that drive SEP-PYY secretion, supporting discovery of druggable and nutrient-driven pathways in metabolic disease.