Silencing the G-protein coupled receptor 3-salt inducible kinase 2 pathway promotes human \u03b2 cell proliferation

Caterina Iorio,Queenie Hu,Robert A Screaton,Tatsuya Kin,Jillian L Rourke,Lisa Wells,Jun-Ichi Sakamaki,Emily Moon

doi:10.1038/s42003-021-02433-2

Abstract

Loss of pancreatic β cells is the hallmark of type 1 diabetes, for which provision of insulin is the standard of care. While regenerative and stem cell therapies hold the promise of generating single-source or host-matched tissue to obviate immune-mediated complications, these will still require surgical intervention and immunosuppression. Here we report the development of a high-throughput RNAi screening approach to identify upstream pathways that regulate adult human β cell quiescence and demonstrate in a screen of the GPCRome that silencing G-protein coupled receptor 3 (GPR3) leads to human pancreatic β cell proliferation. Loss of GPR3 leads to activation of Salt Inducible Kinase 2 (SIK2), which is necessary and sufficient to drive cell cycle entry, increase β cell mass, and enhance insulin secretion in mice. Taken together, our data show that targeting the GPR3-SIK2 pathway is a potential strategy to stimulate the regeneration of β cells.

Highlights

Loss of pancreatic β cells is the hallmark of type 1 diabetes, for which provision of insulin is the standard of care
In a small-scale RNAi screen targeting cell cycle components, we previously reported that ~10% of human β cells enter the cell cycle following silencing of the cyclin-dependent kinase inhibitors (CDKIs) CDKN2C/p18 or CDKN1A/p2112
Our work identifies G-protein coupled receptor 3 (GPR3) as a key cell surface receptor that suppresses Salt Inducible Kinase 2 (SIK2) activity to stabilize CIP/KIP CDKIs and maintain quiescence

Summary

Introduction

Loss of pancreatic β cells is the hallmark of type 1 diabetes, for which provision of insulin is the standard of care. We report the development of a high-throughput RNAi screening approach to identify upstream pathways that regulate adult human β cell quiescence and demonstrate in a screen of the GPCRome that silencing G-protein coupled receptor 3 (GPR3) leads to human pancreatic β cell proliferation. In a small-scale RNAi screen targeting cell cycle components, we previously reported that ~10% of human β cells enter the cell cycle following silencing of the cyclin-dependent kinase inhibitors (CDKIs) CDKN2C/p18 or CDKN1A/p2112. We scale this approach to make it compatible with automation and use it to interrogate an RNAi library targeting the human G protein-coupled receptor (GPCR) family to identify regulators of human β cell proliferation

Methods

Results

Conclusion