The role of senescent beta cells in T1D and T2D

U01应用：衰老的β细胞在T1D和T2D中的作用 摘要 最近的研究包括我们自己的研究表明，表达细胞关键成分的β细胞显著增加 1型糖尿病(T1D)和2型糖尿病(T2D)患者胰岛衰老，与β细胞有关 衰老是胰岛功能障碍的关键因素。最近，有报道称，消融治疗衰老 在T1D和T2D小鼠模型中，通过非特异性感受器分解的细胞改善了疾病的结局。然而，这些 研究没有确定哪种衰老细胞类型与有益效果有关，也没有解决 人内分泌胰腺在发育前和发育过程中的衰老程度如何 T1D和T2D。为了弥合这一知识鸿沟，在具体目标1中，我们将确定流行率、转录 T1D、Pre-T1D和T2D供者β细胞衰老的特征和表观基因组图谱 免疫染色、图像质量分析、单细胞RNAseq、单细胞ATACseq、DNA甲基组 关键组蛋白标记的测定和切割标签分析。此外，我们还将评估假设 端粒不可修复的损伤会导致β细胞衰老，这一可能的情况可能会提供 糖尿病患者胰岛细胞衰老的机制。在具体目标2中，我们将测试 代谢和/或炎症应激致人β细胞衰老，并决定 用单链RNA序列和分泌组分析衰老对β细胞功能的影响。我们将评估是否会诱导 人胰岛细胞衰老及衰老相关分泌表型(SASP)为p16 依赖，使用假性胰岛方法和使用我们的高血糖异种移植模型 评估感觉神经降解剂对人类胰岛功能的直接影响。在具体目标3中，我们将使用一部小说 转基因小鼠，‘SenKiller’模型，使细胞类型特异性和可诱导的衰老细胞在 任何血统，包括β细胞。将此小鼠模型与适当的β细胞特异性Cre结合使用 驱动程序，我们将提供一个明确的答案，如果衰老的β细胞在发展中的关键 T2D模型的糖耐量异常和T1D模型的胰岛自身免疫。总而言之，这项提议将 用大样本队列研究T1D和T2D供者胰岛细胞衰老的发生 多种实验模式，探索衰老的自然驱动因素和对胰岛功能的影响 以及促炎物质的分泌，并利用新的小鼠模型明确地 确定消除衰老的b细胞是否影响T1D和T2D小鼠模型的糖尿病进展。 这里产生的数据将解决现场的紧迫问题，即小岛衰老是否加剧 这些细胞在T1D和T2D的整体病理生理学中是否重要。这些 有关靶向衰老β细胞的潜在疗效的关键问题将具有治疗相关性 用感冒药治疗。

U01 Application: The role of senescent beta cells in T1D and T2D Abstract Recent studies including our own suggest a marked increase in β-cells expressing key components of cellular senescence in islets from Type 1 diabetes (T1D) and Type 2 diabetic (T2D) patients, implicating β-cell senescence as a critical contributor to islet dysfunction. Recently, it was reported that ablation of senescent cells by non-specific senolysis in mouse models of T1D and T2D improved diseease outcome. However, these studies did not determine which senescent cell type was relevant to the beneficial effect, nor did they address to what extent senescence occurs in the human endocrine pancreas before and during the development of T1D and T2D. To close this knowledge gap, in Specific Aim 1 we will determine the prevalence, transcription signatures and epigenomic landscapes of β-cell senescence in T1D, pre-T1D and T2D donors using immunostaining, imaging mass cytometry, single cell RNAseq, single cell ATACseq, DNA methylome determination and Cut-and-Tag analysis for key histone marks. In addition, we will evaluate the hypothesis that irreparable damage to telomeres drives senescence in β-cells, a possible scenario that could provide a mechanism for senescence to occur in islet cells of diabetic patients. In Specific Aim 2, we will test whether metabolic and/or inflammatory stressors drive senescence in human β-cells and determine the effect of senescence on β-cell function using scRNAseq and secretome analysis. We will evaluate if induction of senescence and the senescence-associated secretory phenotype (SASP) in human islet cells is p16 dependent, employing the pseudo-islets approach and using our hyperglycemic xeno-transplantation model to assess the direct effect of senolytics on human islet function. In Specific Aim 3, we will employ a novel transgenic mouse, the ‘SenKiller’ model, to enable cell-type specific and inducible ablation of senescent cells in any lineage including β-cells. Using this mouse model in combination with the appropriate β-cell specific Cre driver, we will provide a definitive answer to the question if senescent β-cells are critical in the development of glucose intolerance in models of T2D and islet autoimmunity in models of T1D. Together, this proposal will determine the occurrence of senescence among islet cells from T1D and T2D donors using large cohorts and multiple experimental modalities, explore the natural drivers of senescence and consequences to islet function as well as secretion of pro-inflammatory substances, and employ novel mouse models to unequivocally determine if elimination of senescent b-cells impacts diabetes progression in mouse models of T1D and T2D. The data generated here will address burning questions in the field, namely, is senescence increased in islets from diabetic patients, and are these cells important in the overall pathophysiology of T1D and T2D. These critical questions will have therapeutic relevance regarding the potential efficacy of targeting senescent β-cells with senolytic therapies.