An Activating STAT3 Mutation Causes Neonatal Diabetes through Premature Induction of Pancreatic Differentiation.
Elsevier (Cell Press)
(C) 2017 The Author(s). This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
Activating germline mutations in STAT3 were recently identified as a cause of neonatal diabetes mellitus associated with beta-cell autoimmunity. We have investigated the effect of an activating mutation, STAT3K392R, on pancreatic development using induced pluripotent stem cells (iPSCs) derived from a patient with neonatal diabetes and pancreatic hypoplasia. Early pancreatic endoderm differentiated similarly from STAT3K392Rand healthy-control cells, but in later stages, NEUROG3 expression was upregulated prematurely in STAT3K392Rcells together with insulin (INS) and glucagon (GCG). RNA sequencing (RNA-seq) showed robust NEUROG3 downstream targets upregulation. STAT3 mutation correction with CRISPR/Cas9 reversed completely the disease phenotype. STAT3K392R-activating properties were not explained fully by altered DNA-binding affinity or increased phosphorylation. Instead, reporter assays demonstrated NEUROG3 promoter activation by STAT3 in pancreatic cells. Furthermore, proteomic and immunocytochemical analyses revealed increased nuclear translocation of STAT3K392R. Collectively, our results demonstrate that the STAT3K392Rmutation causes premature endocrine differentiation through direct induction of NEUROG3 expression.
Anni Laitinen, Eila Korhonen, Hazem Ibrahim, Väinö Lithovius, Noora Aarnio, Jessica Chaffey, and Niina Siiskonen are thanked for their professional technical assistance. We thank Elena Senís (Vall d’Hebron Institute of Oncology) for advice on T7 endonuclease assay. We are grateful to Ras Trokovic and Milla Mikkola for providing iPSC (HEL72.1, HEL72A, and HEL72D) lines. D.B. is a member of the Doctoral School of Health Sciences at University of Helsinki. This project was funded by the Academy of Finland (grant number 257157) Sigrid Jusélius Foundation, Novo Nordisk Foundation (grant numbers NNF16OC0021090, NNF15OC0016426, NNF14OC0010719, and NNF13OC0005565), the EU 7FP Integrated project BETACURE, the Diabetes Research Foundation, and Diabetes UK.
This is the author accepted manuscript. The final version is freely available from Elsevier (Cell Press) via the DOI in this record.
Vol. 19 (2), pp. 281 - 294
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