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Diabetologia. 2020 Feb;63(2):395-409. doi: 10.1007/s00125-019-05046-x. Epub 2019 Dec 3.

Stearoyl CoA desaturase is a gatekeeper that protects human beta cells against lipotoxicity and maintains their identity.

Author information

1
Université Paris Descartes, Institut Cochin, Inserm U1016, 123 bd du Port-Royal, 75014, Paris, France.
2
Unité Biologie Fonctionnelle et Adaptative, CNRS UMR 8251, Paris, France.
3
Bioscience Metabolism, Research and Early Development Cardiovascular Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden.
4
Université Paris Descartes CNRS UMR 8601, Paris, France.
5
ULB Center for Diabetes Research, Université Libre de Bruxelles, Brussels, Belgium.
6
University of Pisa, Department of Clinical and Experimental Medicine, Pisa, Italy.
7
Division of Endocrinology, ULB Erasmus Hospital, Université Libre de Bruxelles, Brussels, Belgium.
8
Université Paris-Sud, CNRS UMR 9197, Institut des Neurosciences Paris-Saclay (Neuro-PSI) - CNRS UMR 9197, Orsay, France.
9
Université Paris Descartes, Institut Cochin, Inserm U1016, 123 bd du Port-Royal, 75014, Paris, France. raphael.scharfmann@inserm.fr.

Abstract

AIMS/HYPOTHESIS:

During the onset of type 2 diabetes, excessive dietary intake of saturated NEFA and fructose lead to impaired insulin production and secretion by insulin-producing pancreatic beta cells. The majority of data on the deleterious effects of lipids on functional beta cell mass were obtained either in vivo in rodent models or in vitro using rodent islets and beta cell lines. Translating data from rodent to human beta cells remains challenging. Here, we used the human beta cell line EndoC-βH1 and analysed its sensitivity to a lipotoxic and glucolipotoxic (high palmitate with or without high glucose) insult, as a way to model human beta cells in a type 2 diabetes environment.

METHODS:

EndoC-βH1 cells were exposed to palmitate after knockdown of genes related to saturated NEFA metabolism. We analysed whether and how palmitate induces apoptosis, stress and inflammation and modulates beta cell identity.

RESULTS:

EndoC-βH1 cells were insensitive to the deleterious effects of saturated NEFA (palmitate and stearate) unless stearoyl CoA desaturase (SCD) was silenced. SCD was abundantly expressed in EndoC-βH1 cells, as well as in human islets and human induced pluripotent stem cell-derived beta cells. SCD silencing induced markers of inflammation and endoplasmic reticulum stress and also IAPP mRNA. Treatment with the SCD products oleate or palmitoleate reversed inflammation and endoplasmic reticulum stress. Upon SCD knockdown, palmitate induced expression of dedifferentiation markers such as SOX9, MYC and HES1. Interestingly, SCD knockdown by itself disrupted beta cell identity with a decrease in mature beta cell markers INS, MAFA and SLC30A8 and decreased insulin content and glucose-stimulated insulin secretion.

CONCLUSIONS/INTERPRETATION:

The present study delineates an important role for SCD in the protection against lipotoxicity and in the maintenance of human beta cell identity.

DATA AVAILABILITY:

Microarray data and all experimental details that support the findings of this study have been deposited in in the GEO database with the GSE130208 accession code.

KEYWORDS:

Dedifferentiation; Human; Lipotoxicity; Pancreatic beta cell; Type 2 diabetes

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