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Bevacqua, R. J.

Publications and source records attributed to Bevacqua, R. J..

2 recordsLinked to original sources

A genome-wide CRISPR screen identifies regulators of beta cell function involved in type 2 diabetes risk

Identification of the genes and processes mediating genetic association signals for complex disease represents a major challenge. Since many of the genetic signals for type 2 diabetes exert their effects through pancreatic islet-cell dysfunction, we performed a genome-wide pooled CRISPR loss-of- function screen in human pancreatic beta cells. We focused on the regulation of insulin content as a disease-relevant readout of beta cell function. We identified 580 genes influencing this phenotype: integration with genetic and genomic data provided experimental support for 20 candidate type 2 diabetes effector transcripts including the autophagy receptor CALCOCO2. Our study highlights how cellular screens can augment existing multi-omic efforts to accelerate biological and translational inference at GWAS loci.

genomics

SIX2 and SIX3 coordinately regulate functional maturity and fate of human pancreatic β-cells

The physiological functions of many vital tissues and organs continue to mature after birth, but the genetic mechanisms governing this postnatal maturation remain an unsolved mystery. Human pancreatic {beta}-cells produce and secrete insulin in response to physiological cues like glucose, and these hallmark functions improve in the years after birth. This coincides with expression of the transcription factors SIX2 and SIX3, whose functions in native human {beta}-cells remain unknown. Here, we show that shRNA-mediated SIX2 or SIX3 suppression in human pancreatic adult islets impairs insulin secretion. However, transcriptome studies revealed that SIX2 and SIX3 regulate distinct targets. Loss of SIX2 markedly impaired expression of genes governing {beta}-cell insulin processing and output, glucose sensing, and electrophysiology, while SIX3 loss led to inappropriate expression of genes normally expressed in fetal {beta}-cells, adult a-cells and other non-{beta}-cells. Chromatin accessibility studies identified genes directly regulated by SIX2. Moreover, {beta}-cells from diabetic humans with impaired insulin secretion also had reduced SIX2 transcript levels. Revealing how SIX2 and SIX3 govern functional maturation and maintain developmental fate in native human {beta}-cells should advance {beta}-cell replacement and other therapeutic strategies for diabetes.

developmental biology