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Elife. 2018 Nov 9;7. pii: e38519. doi: 10.7554/eLife.38519.

Insulin mutations impair beta-cell development in a patient-derived iPSC model of neonatal diabetes.

Author information

1
Research Programs Unit, Molecular Neurology and Biomedicum Stem Cell Centre, Faculty of Medicine, University of Helsinki, Helsinki, Finland.
2
Department of Biosciences, University of Helsinki, Helsinki, Finland.
3
Institute of Biotechnology, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland.
4
University of Eastern Finland and Kuopio University Hospital, Kuopio, Finland.
5
Clinical Genetics, HUSLAB, Helsinki University Central Hospital, Helsinki, Finland.
6
Children's Hospital, University of Helsinki and Helsinki University Hospital, Helsinki, Finland.

Abstract

Insulin gene mutations are a leading cause of neonatal diabetes. They can lead to proinsulin misfolding and its retention in endoplasmic reticulum (ER). This results in increased ER-stress suggested to trigger beta-cell apoptosis. In humans, the mechanisms underlying beta-cell failure remain unclear. Here we show that misfolded proinsulin impairs developing beta-cell proliferation without increasing apoptosis. We generated induced pluripotent stem cells (iPSCs) from people carrying insulin (INS) mutations, engineered isogenic CRISPR-Cas9 mutation-corrected lines and differentiated them to beta-like cells. Single-cell RNA-sequencing analysis showed increased ER-stress and reduced proliferation in INS-mutant beta-like cells compared with corrected controls. Upon transplantation into mice, INS-mutant grafts presented reduced insulin secretion and aggravated ER-stress. Cell size, mTORC1 signaling, and respiratory chain subunits expression were all reduced in INS-mutant beta-like cells, yet apoptosis was not increased at any stage. Our results demonstrate that neonatal diabetes-associated INS-mutations lead to defective beta-cell mass expansion, contributing to diabetes development.

KEYWORDS:

CRISPR-Cas9; Insulin gene mutations; beta-cell development; endoplasmic reticulum stress; human; induced pluripotent stem cells; mTORC1; regenerative medicine; stem cells

PMID:
30412052
DOI:
10.7554/eLife.38519
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