内源神经元DNA双链断裂不足以驱动大脑衰老和神经退行
bioRxiv : the preprint server for biology
|November 1, 2024
概括
神经元中自发的DNA双链断裂 (DSB) 不会导致大脑衰老或神经退行,即使主要的修复途径,即经典非同源端结合 (C-NHEJ) 被禁用. 神经元的DSB积累不足以驱动衰老的表型.
科学领域:
- 神经科学是一个神经科学.
- 遗传学 是一个遗传学.
- 分子生物学分子生物学
背景情况:
- 身体DNA损伤的积累与衰老和神经退行有关.
- 内源性DNA双链断裂 (DSB) 在神经元衰老中的作用尚不清楚.
- 经典非同源端结合 (C-NHEJ) 是一个关键的DNA修复途径.
研究的目的:
- 调查内源性神经元DSBs在大脑衰老和神经退行症中的作用.
- 确定受损C-NHEJ是否有助于与年龄有关的神经元功能障碍.
- 分析DSB积累对神经元基因组完整性和功能的影响.
主要方法:
- 在前脑神经元中产生后发育性Xrcc4无活化的小鼠,Xrcc4是核心C-NHEJ因子.
- 评估了DSB积累,表观遗传变化,基因表达和随年龄的3D基因组组织.
- 在C-NHEJ缺乏的小鼠中评估了神经退行,神经炎症,寿命和认知行为.
主要成果:
- 缺乏C-NHEJ的神经元随着年龄的增长积累了高水平的DSB焦点.
- 内源性神经元DSB优先发生在促进器区域和基因特征中.
- DSB积累诱导了轻微的表观遗传变化,并没有显著改变基因表达或3D基因组组织.
- 缺乏神经元C-NHEJ的小鼠没有表现出神经退行,神经炎症,寿命缩短或认知缺陷.
结论:
- 自发的神经元DSB形成不足以引起大脑衰老和神经退行.
- 主要的神经元DSB修复通路C-NHEJ有效地管理与年龄相关的DNA损伤.
- 神经元衰老和神经退行不仅仅是由内源性DSBs的积累驱动的.
相关概念视频
Fixing Double-strand Breaks
12.3K
The double-stranded structure of DNA has two major advantages. First, it serves as a safe repository of genetic information where one strand serves as the back-up in case the other strand is damaged. Second, the double-helical structure can be wrapped around proteins called histones to form nucleosomes, which can then be tightly wound to form chromosomes. This way, DNA chains up to 2 inches long can be contained within microscopic structures in a cell. A double-stranded break not only damages...
12.3K
Nucleotide Excision Repair
3.4K
DNA Distortion and Damage
Cells are regularly exposed to mutagens—factors in the environment that can damage DNA and generate mutations. UV radiation is one of the most common mutagens and is estimated to introduce a significant number of changes in DNA. These include bends or kinks in the structure, which can block DNA replication or transcription. If these errors are not fixed, the damage can cause mutations, which in turn can result in cancer or disease depending on which sequences are...
Cells are regularly exposed to mutagens—factors in the environment that can damage DNA and generate mutations. UV radiation is one of the most common mutagens and is estimated to introduce a significant number of changes in DNA. These include bends or kinks in the structure, which can block DNA replication or transcription. If these errors are not fixed, the damage can cause mutations, which in turn can result in cancer or disease depending on which sequences are...
3.4K
DNA Damage can Stall the Cell Cycle
9.0K
In response to DNA damage, cells can pause the cell cycle to assess and repair the breaks. However, the cell must check the DNA at certain critical stages during the cell cycle. If the cell cycle pauses before DNA replication, the cells will contain twice the amount of DNA. On the other hand, if cells arrest after DNA replication but before mitosis, they will contain four times the normal amount of DNA. With a host of specialized proteins at their disposal,cells must use the right protein at...
9.0K
Neurogenesis and Regeneration of Nervous Tissue
732
In the CNS, neurogenesis, the birth of new neurons from stem cells, is limited to the hippocampus in adults. In other regions of the brain and spinal cord, neurogenesis is almost non-existent due to inhibitory influences from neuroglia, especially oligodendrocytes, and the absence of growth-stimulating cues. The myelin produced by oligodendrocytes in the CNS inhibits neuronal regeneration. Furthermore, astrocytes proliferate rapidly after neuronal damage, forming scar tissue that physically...
732
Overview of DNA Repair
30.5K
In order to be passed through generations, genomic DNA must be undamaged and error-free. However, every day, DNA in a cell undergoes several thousand to a million damaging events by natural causes and external factors. Ionizing radiation such as UV rays, free radicals produced during cellular respiration, and hydrolytic damage from metabolic reactions can alter the structure of DNA. Damages caused include single-base alteration, base dimerization, chain breaks, and cross-linkage.
Chemically...
Chemically...
30.5K
Replication in Eukaryotes
13.3K
In eukaryotic cells, DNA replication is highly conserved and tightly regulated. Multiple linear chromosomes must be duplicated with high fidelity before cell division, so there are many proteins that fulfill specialized roles in the replication process. Replication occurs in three phases: initiation, elongation, and termination, and ends with two complete sets of chromosomes in the nucleus.
Many Proteins Orchestrate Replication at the Origin
Eukaryotic replication follows many of the same...
Many Proteins Orchestrate Replication at the Origin
Eukaryotic replication follows many of the same...
13.3K


