Journal article
IER3IP1 mutations cause neonatal diabetes due to impaired proinsulin trafficking
Diabetes (New York, N.Y.), Vol.74(4), pp.514-527
04/01/2025
DOI: 10.2337/db24-0119
PMCID: PMC11926274
PMID: 39441964
Abstract
Immediate early response 3 interacting-protein 1 (IER3IP1) is an endoplasmic reticulum resident protein, highly expressed in pancreatic cells and the developing brain cortex. Homozygous mutations in IER3IP1 have been found in individuals with microcephaly and neonatal diabetes, yet the underlying mechanism causing beta cell failure remains unclear. Here, we utilized differentiation of genome edited-stem cells into pancreatic islet cells to elucidate the molecular basis of IER3IP1 neonatal diabetes. Using CRISPR-Cas9, we generated two distinct IER3IP1-mutant human embryonic stem cell lines: a homozygous knock-in model of a patient mutation (IER3IP1V21G), and a knockout model (IER3IP1-/-). While these mutant stem cell lines differentiated normally into definitive endoderm and pancreatic progenitors, we observed that IER3IP1-KO stem cell derived-islets (SC-islets) presented a significant decrease in beta cell numbers and elevated ER stress. Retention Using Selective Hooks (RUSH) assay revealed three-fold reduction in ER-to-Golgi trafficking of proinsulin in IER3IP1 mutant beta cells. Additionally, IER3IP1 mutant SC-islets implanted into immunocompromised mice displayed defective human insulin secretion, indicating the deleterious impact of IER3IP1 mutations on beta cell function. Our study provides valuable insights into the role of IER3IP1 in human beta cell biology and establishes a useful model to investigate ER-to-Golgi trafficking defects within beta cells.Immediate early response 3 interacting-protein 1 (IER3IP1) is an endoplasmic reticulum resident protein, highly expressed in pancreatic cells and the developing brain cortex. Homozygous mutations in IER3IP1 have been found in individuals with microcephaly and neonatal diabetes, yet the underlying mechanism causing beta cell failure remains unclear. Here, we utilized differentiation of genome edited-stem cells into pancreatic islet cells to elucidate the molecular basis of IER3IP1 neonatal diabetes. Using CRISPR-Cas9, we generated two distinct IER3IP1-mutant human embryonic stem cell lines: a homozygous knock-in model of a patient mutation (IER3IP1V21G), and a knockout model (IER3IP1-/-). While these mutant stem cell lines differentiated normally into definitive endoderm and pancreatic progenitors, we observed that IER3IP1-KO stem cell derived-islets (SC-islets) presented a significant decrease in beta cell numbers and elevated ER stress. Retention Using Selective Hooks (RUSH) assay revealed three-fold reduction in ER-to-Golgi trafficking of proinsulin in IER3IP1 mutant beta cells. Additionally, IER3IP1 mutant SC-islets implanted into immunocompromised mice displayed defective human insulin secretion, indicating the deleterious impact of IER3IP1 mutations on beta cell function. Our study provides valuable insights into the role of IER3IP1 in human beta cell biology and establishes a useful model to investigate ER-to-Golgi trafficking defects within beta cells.
Details
- Title: Subtitle
- IER3IP1 mutations cause neonatal diabetes due to impaired proinsulin trafficking
- Creators
- Hossam Montaser - University of HelsinkiSonja Leppänen - University of HelsinkiEliisa Vähäkangas - University of HelsinkiNils Bäck - University of HelsinkiAlicia Grace - University of HelsinkiSolja Eurola - University of HelsinkiHazem Ibrahim - University of HelsinkiVäinö Lithovius - University of HelsinkiSamuel B Stephens - University of IowaTom Barsby - University of HelsinkiDiego Balboa - University of HelsinkiJonna Saarimäki-Vire - University of HelsinkiTimo Otonkoski - Helsinki University Hospital
- Resource Type
- Journal article
- Publication Details
- Diabetes (New York, N.Y.), Vol.74(4), pp.514-527
- DOI
- 10.2337/db24-0119
- PMID
- 39441964
- PMCID
- PMC11926274
- NLM abbreviation
- Diabetes
- ISSN
- 1939-327X
- eISSN
- 1939-327X
- Publisher
- AMER DIABETES ASSOC
- Grant note
- Helsingin Yliopisto10.13039/100007797Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, FinlandHelsinki Institute of Life Science (HiLIFE)Biocenter Finland
Acknowledgments. The authors thank Anna Ahmala, Nea Asumaa, Heli Grym, and Jarkko Ustinov, Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland, for their expert technical assistance and also thank Mirabai Cuenca, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain, for sharing her expertise in lentivirus production and transduction of SC-islets. The authors thank the Institute of Biotechnology Electron Microscopy Unit, University of Helsinki, for providing laboratory facilities. Confocal imaging was performed at the Biomedicum Imaging Unit, University of Helsinki, supported by the Helsinki Institute of Life Science (HiLIFE) and Biocenter Finland.
- Language
- English
- Electronic publication date
- 10/23/2024
- Date published
- 04/01/2025
- Academic Unit
- Fraternal Order of Eagles Diabetes Research Center; Endocrinology and Metabolism; Internal Medicine
- Record Identifier
- 9984738391902771
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