Loss of ZNF148 enhances insulin secretion in human pancreatic β cells
Eleonora de Klerk, Yini Xiao, Christopher H. Emfinger, Mark P. Keller, David I. Berrios, Valentina Loconte, Axel A. Ekman, Kate L. White, Rebecca L. Cardone, Richard G. Kibbey, Alan D. Attie, Matthias Hebrok
Eleonora de Klerk, Yini Xiao, Christopher H. Emfinger, Mark P. Keller, David I. Berrios, Valentina Loconte, Axel A. Ekman, Kate L. White, Rebecca L. Cardone, Richard G. Kibbey, Alan D. Attie, Matthias Hebrok
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Research Article Metabolism Stem cells

Loss of ZNF148 enhances insulin secretion in human pancreatic β cells

Abstract

Insulin secretion from pancreatic β cells is essential to the maintenance of glucose homeostasis. Defects in this process result in diabetes. Identifying genetic regulators that impair insulin secretion is crucial for the identification of novel therapeutic targets. Here, we show that reduction of ZNF148 in human islets, and its deletion in stem cell–derived β cells (SC–β cells), enhances insulin secretion. Transcriptomics of ZNF148-deficient SC–β cells identifies increased expression of annexin and S100 genes whose proteins form tetrameric complexes involved in regulation of insulin vesicle trafficking and exocytosis. ZNF148 in SC–β cells prevents translocation of annexin A2 from the nucleus to its functional place at the cell membrane via direct repression of S100A16 expression. These findings point to ZNF148 as a regulator of annexin-S100 complexes in human β cells and suggest that suppression of ZNF148 may provide a novel therapeutic strategy to enhance insulin secretion.

Authors

Eleonora de Klerk, Yini Xiao, Christopher H. Emfinger, Mark P. Keller, David I. Berrios, Valentina Loconte, Axel A. Ekman, Kate L. White, Rebecca L. Cardone, Richard G. Kibbey, Alan D. Attie, Matthias Hebrok

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Figure 6

Ectopic expression of S100A16 mediates cellular translocation of annexin A2 and increased first-phase insulin secretion.

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Ectopic expression of S100A16 mediates cellular translocation of annexin...
(A) ZNF148 binding site motifs from TRANSFAC and predicted ZNF148 targets from the S100 family. (B) RNA-Seq expression levels of S100A16 in control and ZNF148-KO eBC. n = 3 independent samples. TPM, transcripts per million. (C) Schematic representation of S100A16 locus. Predicted binding site for ZNF148 (green) and location of ChIP-qPCR primers. (D) RNA-Seq expression levels of GAST in control and ZNF148-KO eBC (clone A). n = 3 independent samples. (E) ChIP-qPCR quantification of DNA input recovery for gastrin (positive control), S100A16, and myoglobin (negative control) in 20,000 human IEQs. (F) Schematic representation of the DOX-inducible S100A16 overexpression clonal line. (G) Immunofluorescence staining of ZNF148 (yellow) in eBC after treatment (48 hours) with exogenous ANXA2 alone (top panel, 6× magnification of the boxed area) or in combination with DOX treatment (8 hours) (bottom panel, 8× magnification of the boxed area). White arrows indicate prominent nuclear localization of ANXA2 in control eBC treated only with exogenous ANXA2 and prominent membrane and cytoplasmic localization in DOX/ANXA2-treated eBC. DAPI staining depicts nuclei (blue). Scale bar: 50 μm. (H) Dynamic glucose-stimulated C-peptide secretion in eBCs treated with or without DOX to stimulate S100A16 expression and with or without ANXA2/ANXA1 (n = 5 for each group; 80 eBCs each group). (I) C-peptide secretion at the peak of first-phase secretion (26 minutes) in each of the groups shown in H. n = 5 for each group. (J) AUC of C-peptide secretion from 2.8 mM basal low and 2 0mM high glucose incubation shown in H. n = 5 for each group. Data are presented as mean ± SEM. *P < 0.05; **P < 0.01; ***P < 0.001; NS, not significant determined by 2-tailed unpaired Student’s t test.