contributed equally

Identifying the mechanisms behind the β-cell adaptation-to-failure is important to develop strategies to manage type 2 diabetes (T2D). Using db/db mice at early stages of the disease process, we took advantage of unbiased RNAseq to identify genes/pathways regulated by insulin resistance in β-cells. We demonstrate herein that islets from 4-week-old non-obese and non-diabetic leptin-receptor deficient db/db mice exhibited downregulation of several genes involved in cell-cycle regulation and DNA repair. We identified the transcription factor Yin Yang 1 (YY1) as a common gene between both pathways. The expression of YY1 and its targeted genes was decreased in the db/db islets. We confirmed the reduction in YY1 expression in β-cells from diabetic db/db mice, mice fed high fat diet (HFD) and individuals with T2D. ChIP-seq profiling in EndocBH1 cells, a human pancreatic β-cell line, indicated that YY1 binding regions regulate cell-cycle control, DNA damage recognition and repair. We then generated mouse models with constitutive and inducible YY1 deficiency in β-cells. YY1 deficient mice developed diabetes early in life due to β-cell loss. β-cells from these mice exhibited higher DNA damage, cell cycle arrest and cell death as well as decreased maturation markers. Tamoxifen-induced YY1 deficiency in mature β-cells impaired β-cell function and induced DNA damage. In summary, we identified YY1 as a critical factor for β-cell DNA repair and cell-cycle progression.

This article contains supplementary material online at https://doi.org/10.2337/figshare.19723336.

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