背景:运动神经元在起源和周围环境等方面与感觉神经元不同。了解对周围神经损伤(PNI)的分子反应以及感觉和运动神经元之间的再生的异同对于开发用于CNS再生的有效药物靶标至关重要。然而,PNI后感觉和运动神经元分子变化的全基因组比较仍然有限.
目的:本研究旨在研究全基因组范围内感觉和运动神经元损伤反应的趋同和差异,以确定新的神经修复药物靶点。
方法:我们分析了PNI上原位捕获的感觉神经元(SNs)和运动神经元(MNs)的两个大规模RNA-seq数据集,中枢神经系统损伤后的视网膜神经节细胞和脊髓。此外,我们将这些与其他相关的单细胞级数据集集成在一起。BootstrapDESeq2和WGCNA用于检测和探索差异表达基因(DEG)的共表达模块。
结果:我们发现SNs和MNs表现出相似的损伤状态,但是MN的反应延迟。我们确定了一个具有274个共享DEG的保守再生相关模块(cRAM)。其中,在单细胞分辨率数据集支持的受损神经元中,可以改变47%的DEG。我们还在cRAM中发现了一些研究较少的候选人,包括与转录相关的基因,泛素化(Rnf122),和神经元免疫细胞串扰。进一步的体外实验证实了Rnf122在轴突生长中的新作用。对差异较大的前10%DEG的分析表明,两者都是外在的(例如,免疫微环境)和内在因素(例如,发育)有助于损伤后SNs和MNs之间的表达差异。
结论:这项综合分析揭示了SNs和MNs中趋同和发散的损伤反应基因,为响应轴突损伤和随后的再生的感觉和运动神经元的转录重编程提供新的见解。它还确定了一些新的再生相关候选物,可以促进轴突再生策略的发展。
BACKGROUND: Motor neurons differ from sensory neurons in aspects including origins and surrounding environment. Understanding the similarities and differences in molecular response to peripheral nerve injury (PNI) and regeneration between sensory and motor neurons is crucial for developing effective drug targets for CNS regeneration. However, genome-wide comparisons of molecular changes between sensory and motor neurons following PNI remains limited.
OBJECTIVE: This study aims to investigate genome-wide convergence and divergence of injury response between sensory and motor neurons to identify novel drug targets for neural repair.
METHODS: We analyzed two large-scale RNA-seq datasets of in situ captured sensory neurons (SNs) and motoneurons (MNs) upon PNI, retinal ganglion cells and spinal cord upon CNS injury. Additionally, we integrated these with other related single-cell level datasets. Bootstrap DESeq2 and WGCNA were used to detect and explore co-expression modules of differentially expressed genes (DEGs).
RESULTS: We found that SNs and MNs exhibited similar injury states, but with a delayed response in MNs. We identified a conserved regeneration-associated module (cRAM) with 274 shared DEGs. Of which, 47% of DEGs could be changed in injured neurons supported by single-cell resolution datasets. We also identified some less-studied candidates in cRAM, including genes associated with transcription, ubiquitination (Rnf122), and neuron-immune cells cross-talk. Further in vitro experiments confirmed a novel role of Rnf122 in axon growth. Analysis of the top 10% of DEGs with a large divergence suggested that both extrinsic (e.g., immune microenvironment) and intrinsic factors (e.g., development) contributed to expression divergence between SNs and MNs following injury.
CONCLUSIONS: This comprehensive analysis revealed convergent and divergent injury response genes in SNs and MNs, providing new insights into transcriptional reprogramming of sensory and motor neurons responding to axonal injury and subsequent regeneration. It also identified some novel regeneration-associated candidates that may facilitate the development of strategies for axon regeneration.