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J Biol Chem. 2017 Feb 24;292(8):3466-3480. doi: 10.1074/jbc.M116.748335. Epub 2017 Jan 11.

Neuron-enriched RNA-binding Proteins Regulate Pancreatic Beta Cell Function and Survival.

Author information

1
From the ULB Center for Diabetes Research, Université Libre de Bruxelles, 1070 Brussels, Belgium, mjuanmat@ulb.ac.be.
2
From the ULB Center for Diabetes Research, Université Libre de Bruxelles, 1070 Brussels, Belgium.
3
the Lund University Diabetes Center, Unit of Islets Cell Exocytosis, Department of Clinical Sciences Malmö, Lund University, SE 205 02 Malmö, Sweden.
4
the Department of Clinical and Experimental Medicine, Islet Cell Laboratory, University of Pisa, 56126 Pisa, Italy, and.
5
From the ULB Center for Diabetes Research, Université Libre de Bruxelles, 1070 Brussels, Belgium, deizirik@ulb.ac.be.
6
Welbio, Université Libre de Bruxelles, 808 Route de Lennik, CP618, 1070 Brussels, Belgium.

Abstract

Pancreatic beta cell failure is the central event leading to diabetes. Beta cells share many phenotypic traits with neurons, and proper beta cell function relies on the activation of several neuron-like transcription programs. Regulation of gene expression by alternative splicing plays a pivotal role in brain, where it affects neuronal development, function, and disease. The role of alternative splicing in beta cells remains unclear, but recent data indicate that splicing alterations modulated by both inflammation and susceptibility genes for diabetes contribute to beta cell dysfunction and death. Here we used RNA sequencing to compare the expression of splicing-regulatory RNA-binding proteins in human islets, brain, and other human tissues, and we identified a cluster of splicing regulators that are expressed in both beta cells and brain. Four of them, namely Elavl4, Nova2, Rbox1, and Rbfox2, were selected for subsequent functional studies in insulin-producing rat INS-1E, human EndoC-βH1 cells, and in primary rat beta cells. Silencing of Elavl4 and Nova2 increased beta cell apoptosis, whereas silencing of Rbfox1 and Rbfox2 increased insulin content and secretion. Interestingly, Rbfox1 silencing modulates the splicing of the actin-remodeling protein gelsolin, increasing gelsolin expression and leading to faster glucose-induced actin depolymerization and increased insulin release. Taken together, these findings indicate that beta cells share common splicing regulators and programs with neurons. These splicing regulators play key roles in insulin release and beta cell survival, and their dysfunction may contribute to the loss of functional beta cell mass in diabetes.

KEYWORDS:

alternative splicing; apoptosis; autoimmunity; beta cell (B-cell); diabetes; insulin secretion

PMID:
28077579
PMCID:
PMC5336178
DOI:
10.1074/jbc.M116.748335
[Indexed for MEDLINE]
Free PMC Article

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