The impact of reduction of cellular senescence on age-related epigenetic heterogeneity

项目总结 本申请是为了回应被确认为非CA-CA的特殊利益通知(NOSI)而提交的 23-045.随着年龄的增长，造血干细胞和祖细胞(HSPC)功能的下降会导致不适当的 血液和免疫细胞的产生，导致健康和寿命下降。陈旧的HSPC积累起来 赋予选择性适应优势的体细胞突变，导致克隆性造血(CH)，一种血液 表型会增加患白血病和包括心血管疾病在内的各种老年病的风险。 细胞衰老是衰老的一个标志，也是与年龄相关的CH的另一个强有力的外部候选驱动因素 骨髓微环境。衰老细胞会分泌影响其功能的炎症因子 以及周围细胞的分化，包括对驱动CH至关重要的细胞因子。确定影响 延缓细胞衰老对老龄小鼠骨髓HSPC表观遗传异质性的影响 对于衰老和癌症研究具有重要意义，因为HSPC随着年龄的增长具有更大的表观遗传学异质性 改变干细胞在造血中的功能，增加白血病进展的几率。我们将测试 认为通过减少衰老来恢复骨髓微环境活力的假说 HSPC的表观遗传异质性。这一知识可以帮助开发新的治疗和 预防策略，以减轻与年龄相关的血液疾病，最终有利于预防两者 老年人造血功能下降，血液恶性风险增加。追随特定亚克隆的命运 在造血干细胞中，我们将唯一地对数千只来自旧野生型小鼠的造血干细胞进行条形码编码，这些干细胞将被移植到 三组宿主小鼠接受载体或感觉神经溶解治疗以确定老化与恢复BM的方式 微环境影响HSPC的异质性。我们将使用scRNA-seq和snatac-seq分析来鉴定 细胞簇相关的表观遗传和转录特征以及相关的异质性。 收缩的HSC克隆。我们还将识别依赖衰老的表观遗传学特征和相关的 移植后SNATAC-SEQ数据的异质性。这项研究的预期结果将是 细胞衰老延缓对老年骨HSPC表观遗传异质性的影响 小鼠的骨髓，并确定在恢复活力、较少炎症的情况下，调节的特定途径 微环境。这项工作可以为理解年龄相关行为的启动提供一个机制基础 血液紊乱。

PROJECT SUMMARY This application is being submitted in response to the Notice of Special Interest (NOSI) identified as NOT-CA- 23-045. The decline in hematopoietic stem and progenitor cell (HSPC) function with aging can lead to improper blood and immune cell production, contributing to reduced health and life span. Aged HSPCs accumulate somatic mutations that confer a selective fitness advantage, leading to clonal hematopoiesis (CH), a blood phenotype that increases the risk of leukemia and various diseases of aging including cardiovascular diseases. Cellular senescence, a hallmark of aging, is another potent extrinsic candidate driver for age-related CH in the bone marrow microenvironment. Senescent cells secrete inflammatory factors that can influence the function and differentiation of surrounding cells, including cytokines that are crucial for driving CH. Determining the impact of reducing cellular senescence on the epigenetic heterogeneity of HSPC in aged bone marrow of mice is significant for aging and cancer research, given that greater epigenetic heterogeneity of HSPC with age should alter both stem cell functionality in hematopoiesis and increase the odds of leukemic progression. We will test the hypothesis that rejuvenating the bone marrow microenvironment by reducing senescence will reduce epigenetic heterogeneity of HSPC. This knowledge can contribute to the development of novel therapeutic and preventative strategies for mitigating age-related blood disorders, ultimately benefiting prevention of both hematopoietic decline and increased blood malignancy risk in the elderly. To follow the fate of specific subclones of HSCs, we will uniquely barcode thousands of HSC from old wildtype mice, which will be transplanted into three groups of host mice with vehicle or senolytic treatment to determine how aged vs. rejuvenated BM microenvironment influences HSPC heterogeneity. We will use scRNA-seq and snATAC-seq analysis to identify cell cluster-associated epigenetic and transcriptomic signatures and associated heterogeneity for expanded vs. contracted HSC clones. We will also identify senescence-dependent epigenetic signatures and associated heterogeneity from post-transplantation snATAC-seq data. The expected outcomes of this research will be to determine the impact of cellular senescence reduction on the epigenetic heterogeneity of HSPC in aged bone marrow of mice and identify the specific pathways that are modulated given the rejuvenated, less inflammatory microenvironment. This work can provide a mechanistic foundation for understanding the initiation of age-related blood disorders.