Malfunctioning DDR and metabolism drive cerebellar pathologies in genetic instability disorders

DDR 和代谢功能障碍导致遗传不稳定疾病中的小脑病理

• 批准号: 465316902
• 负责人: Professor Dr. Christoph Englert, since 4/2023
• 金额: --
• 依托单位: Leibniz-Institut für Alternsforschung - Fritz-Lipmann-Institut e.V. (FLI)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/465316902?language=en
• 关键词: Malfunctioning; DDR; metabolism; drive; cerebellar

The genome is constantly challenged by endogenous and exogenous damaging insults. Cells evolve two key DNA damage response (DDR) pathways, which are mediated by ATM and ATR. The MRN (MRE11/RAD50/NBS1) complex functions mainly to activate ATM in response to DNA double strand breaks (DSBs) and also regulates the ATR activation in response to replication stress. Mutations of ATM, ATR, NBS1 and MRE11 cause Ataxia-Telangiectasia (A-T), Seckel Syndrome (SS), Nijmegen Breakage Syndrome (NBS) and A-T Like Disorder (A-TLD), respectively. A-T and A-TLD are associated with cerebellar degeneration, NBS and ATR-SS are characterized by microcephaly and mental retardation. It is well known yet puzzling that mutations of DDR molecules and repair pathways cause neurological symptoms, which are often associated with defects in the cerebellum, leading to ataxia in human patients and mouse models; however, why cerebella, but not cerebral cortex, are vulnerable to DDR malfunction is a long-term unsolved mystery. To understand the molecular pathways of these disorders, Nbs1, Mre11, Atm, and Atr mutant mouse models have been generated. We found that although surprisingly Atr, Nbs1 and Mre11 are not required for survival of postmitotic neurons, they have other novel physiological functions, for example in mitochondria and metabolism, vascular integrity and presynaptic activities. We hypotheses that neurological defects of these genomic instability disorders A-T, SS, A-TLD and NBS are developmental as well as metabolic disorders and that these disorders are caused by the failure of the canonical as well as the non-canonical functions of these DDR players. We therefore set up the following objectives: (1) To study the molecular pathways that render the cerebellar neuroprogenitors susceptible to the DDR malfunction (2) To elucidate the function of metabolism as a regulator of cerebellar attrition of DDR deficiency(3) To discover and characterize the environmental factors such as vascular integrity in preventing cerebellar defects We will take the following approaches: (i) Molecular and genetic dissection of the DDR in cerebellar development and maintenance. (ii) Integrated omics including targeted metabolic analysis and single cell RNA-seq in neuron and non-neuronal cells as well as neuronal activity. (iii) Molecular and imaging analyses of vascular integrity in cerebella in comparison with cerebral cortices.Our study will lead to new discovery of molecular pathways that under control by the DDR proteins in neuropathies particularly the specificity of cerebella in genomic instability syndromes. The understanding of the nature of the ataxia related disorders will not only deliver pharmaceutical strategies for the individuals, but also shed light on the fundamental biology of the cerebellum development, functionality and its maintenance.

基因组不断受到内源性和外源性损伤的挑战。细胞进化出两条关键的 DNA 损伤反应 (DDR) 途径，由 ATM 和 ATR 介导。 MRN (MRE11/RAD50/NBS1) 复合物的主要功能是响应 DNA 双链断裂 (DSB) 激活 ATM，并调节 ATR 激活以响应复制应激。 ATM、ATR、NBS1 和 MRE11 突变分别导致共济失调毛细血管扩张症 (A-T)、塞克尔综合征 (SS)、奈梅亨断裂综合征 (NBS) 和 A-T 样紊乱 (A-TLD)。 A-T 和 A-TLD 与小脑变性有关，NBS 和 ATR-SS 的特点是小头畸形和智力低下。众所周知但令人费解的是，DDR分子和修复途径的突变会引起神经系统症状，这些症状通常与小脑缺陷有关，导致人类患者和小鼠模型出现共济失调；然而，为什么小脑而不是大脑皮层容易受到DDR故障的影响，这是一个长期未解之谜。为了了解这些疾病的分子途径，我们建立了 Nbs1、Mre11、Atm 和 Atr 突变小鼠模型。我们发现，尽管令人惊讶的是 Atr、Nbs1 和 Mre11 并不是有丝分裂后神经元存活所必需的，但它们具有其他新的生理功能，例如在线粒体和代谢、血管完整性和突触前活动中。我们假设这些基因组不稳定疾病 A-T、SS、A-TLD 和 NBS 的神经缺陷是发育和代谢疾病，并且这些疾病是由这些 DDR 参与者的规范和非规范功能的失败引起的。因此，我们设定了以下目标：(1) 研究使小脑神经祖细胞易受 DDR 功能障碍影响的分子途径 (2) 阐明代谢作为 DDR 缺陷小脑消耗调节的功能 (3) 发现和描述环境因素（例如血管完整性）在预防小脑缺陷方面的作用。我们将采取以下方法：（i）对小脑发育和维护中的 DDR 进行分子和遗传解剖。 (ii) 综合组学，包括神经元和非神经元细胞以及神经元活动的靶向代谢分析和单细胞 RNA-seq。 (iii) 与大脑皮质相比，小脑血管完整性的分子和成像分析。我们的研究将导致神经病中 DDR 蛋白控制的分子途径的新发现，特别是小脑在基因组不稳定综合征中的特异性。了解共济失调相关疾病的性质不仅可以为个体提供药物策略，还可以阐明小脑发育、功能及其维持的基础生物学。