RFX6 haploinsufficiency predisposes to diabetes through impaired beta cell function

作者：Hazem Ibrahim, Diego Balboa, Jonna Saarimäki‐Vire, Hossam Montaser, Oleg Dyachok, Per-Eric Lund, Muhmmad Omar‐Hmeadi, Jouni Kvist, Om Prakash Dwivedi, Väinö Lithovius, Tom Barsby, Vikash Chandra, Solja Eurola, Jarkko Ustinov, Tiinamaija Tuomi, Päivi J. Miettinen, Sebastian Barg, Anders Tengholm, Timo Otonkoski · 发表于：Diabetologia · 年份：2024 · DOI：10.1007/s00125-024-06163-y · 被引用次数：21 · 研究领域：Pancreatic function and diabetes、Diabetes and associated disorders、Pluripotent Stem Cells Research

AIMS/HYPOTHESIS: Regulatory factor X 6 (RFX6) is crucial for pancreatic endocrine development and differentiation. The RFX6 variant p.His293LeufsTer7 is significantly enriched in the Finnish population, with almost 1:250 individuals as a carrier. Importantly, the FinnGen study indicates a high predisposition for heterozygous carriers to develop type 2 and gestational diabetes. However, the precise mechanism of this predisposition remains unknown. METHODS: To understand the role of this variant in beta cell development and function, we used CRISPR technology to generate allelic series of pluripotent stem cells. We created two isogenic stem cell models: a human embryonic stem cell model; and a patient-derived stem cell model. Both were differentiated into pancreatic islet lineages (stem-cell-derived islets, SC-islets), followed by implantation in immunocompromised NOD-SCID-Gamma mice. RESULTS: SC-islets exhibited RFX6 haploinsufficiency (54.2% reduction in protein expression), associated with reduced beta cell maturation markers, altered calcium signalling and impaired insulin secretion (62% and 54% reduction in basal and high glucose conditions, respectively). However, RFX6 haploinsufficiency did not have an impact on beta cell number or insulin content. The reduced insulin secretion persisted after in vivo implantation in mice, aligning with the increased risk of variant carriers to develop diabetes. CONCLUSIONS/INTERPRETATION: Our allelic series isogenic SC-islet models repr...