Interrogating the role of m6A mRNA methylation in the aging of the β-cell and diabetes

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PROJECT SUMMARY Although the etiopathogenesis of Type 1 (T1D) and Type 2 diabetes (T2D) is different, decreased functional β-cell mass is a central feature in both diseases. Concerted research efforts aim at developing strategies to improve β-cell survival and restore β-cell function in patients with diabetes. Cellular senescence is a major hallmark of aging. Recent work has demonstrated that β-cell senescence is a common contributor to Type 1 diabetes (T1D) and Type 2 diabetes (T2D). RNA modifications are emerging as important modulators of many hallmarks of aging. We have discovered that m6A mRNA methylation is essential for β-cell function and survival, and recently characterized the m6A landscape of human T1D and T2D islets. Our preliminary data shows that the m6A eraser ALKBH5 is upregulated in aged human β-cells and differentially m6A methylated genes in T1D and T2D are enriched for DNA damage response and senescence pathways compared to controls. The goal of this application is to use state-of-the art methods to characterize the m6A methylome of the aging β- cell and identify m6A-regulated pathways that underlie the accelerated β-cell senescence in diabetes. I will test the overarching hypothesis that aging β-cells exhibit transcript-specific m6A hypomethylation and consequent upregulation of mRNAs involved in driving cell senescence, and that m6A is therefore a valuable therapeutic target for diabetes. In Specific Aim 1, I will characterize the temporal m6A landscape of the aging β-cell. Completion of Aim 1, which will take place during K99 phase, will provide me with training in aspects of aging biology and further experience with bioinformatics analysis of m6A data necessary to independently complete the R00 phase and future R01 submissions. In Specific Aim 2, which will span the K99 and R00 phases, I will identify the molecular targets of ALKBH5 in the human β-cell transition to senescence. Completion of the sub- aim of Aim 2 proposed during the K99 phase will provide me with the training in photoactivatable ribonucleoside- enhanced crosslinking and immunoprecipitation (PAR-CLIP) sequencing and data analysis necessary to complement Aim 1, and independently complete Aim 2 during the R00 phase. For Specific Aim 3, I will target m6A levels to reduce β-cell senescence and improve diabetes in vivo. Completion of this aim will allow me to validate candidate genes identified in Aim’s 1 and 2 and to test in vivo the role of Alkbh5 in driving the accelerated senescence seen in β-cells in diabetes. These experiments are novel as they combine omics-based approaches, mouse genetic models, physiology, and molecular biology to examine the mechanistic role of m6A, and particularly ALKBH5, in β-cell senescence transition in diabetes.