The pathophysiological relevance of the histone variant H2A.J in radiation-induced, premature senescence

组蛋白变体 H2A.J 在辐射诱导的过早衰老中的病理生理学相关性

• 批准号: 394229105
• 负责人: Professorin Dr. Claudia Rübe
• 金额: --
• 依托单位: Klinik für Strahlentherapie und Radioonkologie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2023-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/394229105?language=en
• 关键词: pathophysiological; relevance; histone; variant; H2A.J

The long term side effects following radiotherapy can be traced back to the accumulation of dysfunctional senescent cells combined with the reduced proliferative potential of tissue-specific stem cells; to date the pathomechanisms however remain unclear. In our preliminary studies, we have characterized the novel histone variant H2A.J, whose integration into chromatin increases following ionizing radiation and additionally is associated with cellular senescence.The aim of this research project is to investigate the importance of the histone variant H2A.J in relation to radiation-induced, premature senescence both in-vitro and in-vivo. The molecular biological relationship between radiation-induced DNA damage, local chromatin modifications and subsequent global reorganization of the chromatin architecture is to be investigated using comparative studies between H2A.J+/+ and H2A.J-/- fibroblasts through the means of light- and electron microscopy. Additionally, the alterations in chromatin organization and nuclear integrity shall be structurally and functionally characterized using multi-parametric flow cytometry. The application of high-resolution, precise 3D reconstruction of the entire cell nucleus shall be used to uncover the connections between the chromatin integration of H2A.J following irradiation and the functional reorganization of chromatin.Furthermore, the functionality of H2A.J is to be investigated in the complex tissue configuration of the skin, during and after irradiation. Located in the murine epidermis is the hair follicle and its bulge region which presents an ideal model for the analysis of the differentiation processes of epidermal stem cells. To examine the effect on tissue homeostasis, the radiation-induced DNA damage in different stem cell populations shall be correlated with the chromatin integration of H2A.J and collated with proliferation, differentiation, apoptosis and senescence respectively. Analysis of the specific function of H2A.J in the epidermis shall be inspected in transgenic H2A.J-/- mice. In specific, how the missing H2A.J expression influences premature senescence or, as the case may be, the untimely differentiation of epidermal stem cells, following irradiation. The use of BrdU labeling will capture the division rate, as well as, the self-renewal of the stem cell population and, combined with H2A.J detection, will be collated with premature differentiation. As increased migration of stem cells from their niche leads to a reduced regeneration capacity of the hair follicle in the long term, the functional endpoint of hair growth and coloring shall be analyzed.Overall, the pathophysiological relevance of the histone variant H2A.J in radiation-induced, premature senescence and the untimely differentiation of epidermal stem cells respectively, is to be investigated to uncover possible starting points for the development of a corrective pharmacological therapy.

放疗后的长期副作用可以追溯到功能失调的衰老细胞的积累以及组织特异性干细胞增殖潜力的降低。然而迄今为止，其病理机制仍不清楚。在我们的初步研究中，我们表征了新型组蛋白变体 H2A.J，其与染色质的整合在电离辐射后增加，并且与细胞衰老相关。该研究项目的目的是研究组蛋白变体 H2A.J 在体外和体内与辐射诱导的过早衰老相关的重要性。辐射诱导的 DNA 损伤、局部染色质修饰和随后染色质结构的整体重组之间的分子生物学关系将通过光学和电子显微镜对 H2A.J+/+ 和 H2A.J-/- 成纤维细胞进行比较研究来研究。此外，染色质组织和核完整性的改变应使用多参数流式细胞术进行结构和功能表征。应用高分辨率、精确的整个细胞核 3D 重建来揭示照射后 H2A.J 的染色质整合与染色质功能重组之间的联系。此外，将在照射期间和照射后研究 H2A.J 在皮肤复杂组织结构中的功能。毛囊及其隆起区域位于小鼠表皮中，为分析表皮干细胞的分化过程提供了理想的模型。为了检查对组织稳态的影响，不同干细胞群中辐射诱导的 DNA 损伤应与 H2A.J 的染色质整合相关，并分别与增殖、分化、凋亡和衰老相关。 H2A.J在表皮中的具体功能的分析应在转基因H2A.J-/-小鼠中进行检查。具体来说，缺失的 H2A.J 表达如何影响过早衰老，或者根据具体情况影响照射后表皮干细胞的过早分化。 BrdU 标记的使用将捕获干细胞群的分裂率以及自我更新，并与 H2A.J 检测相结合，将与过早分化进行比较。由于从长远来看，干细胞从其生态位迁移的增加会导致毛囊再生能力降低，因此应分析毛发生长和着色的功能终点。总体而言，将研究组蛋白变体 H2A.J 分别在辐射诱导的表皮干细胞过早衰老和过早分化中的病理生理学相关性，以揭示表皮干细胞发育的可能起点。 纠正性药物治疗。