TY - JOUR T1 - Human pseudoislet system enables detection of differences in G-protein-coupled-receptor signaling pathways between α and β cells JF - bioRxiv DO - 10.1101/842989 SP - 842989 AU - John T. Walker AU - Rachana Haliyur AU - Heather A. Nelson AU - Matthew Ishahak AU - Gregory Poffenberger AU - Radhika Aramandla AU - Conrad Reihsmann AU - Joseph R. Luchsinger AU - Diane C. Saunders AU - Peng Wang AU - Adolfo Garcia-Ocaña AU - Rita Bottino AU - Ashutosh Agarwal AU - Alvin C. Powers AU - Marcela Brissova Y1 - 2019/01/01 UR - http://biorxiv.org/content/early/2019/11/14/842989.abstract N2 - G-protein-coupled-receptors (GPCRs) modulate insulin secretion from β cells and glucagon secretion from α cells. Here, we developed an integrated approach to study the function of primary human islet cells using genetically modified pseudoislets that resemble native islets across multiple parameters. We studied the Gi and Gq GPCR pathways by expressing the designer receptors exclusively activated by designer drugs (DREADDs) hM4Di or hM3Dq. Activation of Gi signaling reduced insulin and glucagon secretion, while activation of Gq signaling stimulated glucagon secretion but had both stimulatory and inhibitory effects on insulin secretion. Further, we developed a microperifusion system that allowed synchronous acquisition of GCaMP6f biosensor signal and hormone secretory profiles and showed that the dual effects for Gq signaling occur through changes in intracellular Ca2+. By combining pseudoislets with a microfluidic system, we co-registered intracellular signaling dynamics and hormone secretion and demonstrated differences in GPCR signaling pathways between human β and α cells. ER -