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

项目摘要 本申请是为了响应被标识为NOT-CA的特别利益通知（NOSI）而提交的- 23-045.随着年龄的增长，造血干细胞和祖细胞（HSPC）功能的下降可能导致不适当的造血干细胞和祖细胞（HSPC）功能的下降。 血液和免疫细胞的生产，有助于减少健康和寿命。老化HSPC蓄积 体细胞突变，赋予选择性适应性优势，导致克隆造血（CH），血液 表型，增加患白血病和包括心血管疾病在内的各种老年疾病的风险。 细胞衰老是衰老的标志，是年龄相关CH的另一个有效的外在候选驱动因素， 骨髓微环境衰老细胞分泌炎症因子， 以及周围细胞的分化，包括对驱动CH至关重要的细胞因子。 降低细胞衰老对老年小鼠骨髓中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随年龄增长表观遗传异质性更大， 改变造血中的干细胞功能并增加白血病进展的几率。我们将测试 通过减少衰老来恢复骨髓微环境将减少 HSPC的表观遗传异质性。这些知识可以有助于开发新的治疗药物， 预防策略，以减轻与年龄有关的血液疾病，最终有利于预防两者 老年人造血功能下降和血液恶性肿瘤风险增加。为了追踪特定亚克隆的命运 我们将对来自老年野生型小鼠的数千个HSC进行独特的条形码化，这些HSC将被移植到 用媒介物或衰老清除剂处理的三组宿主小鼠，以确定老化与再生的BM 微环境影响HSPC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组学特征和相关的异质性， HSC克隆。我们还将确定衰老依赖的表观遗传特征和相关的 来自移植后snATAC-seq数据的异质性。这项研究的预期成果将是 确定细胞衰老减少对老年骨中HSPC表观遗传异质性的影响 小鼠的骨髓，并确定特定的途径，调制给予振兴，炎症较少 微环境这项工作可以提供一个机制的基础，了解启动的年龄有关的 血液疾病

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.