Sox4调控小胶质细胞活化和炎症因子表达及其在脊髓缺血再灌注损伤进展中的作用和机制研究

Spinal cord ischemia-reperfusion injury (SCII) is a disease with high morbidity and mortality, the regulation mechanism of its development is an important scientific question.Microglial cell activation and inflammatory cytokines production is the key factor of SCII progression, in which the activation of TLRs signaling pathway is the initiating factor and the activation of the molecular regulatory mechanisms have attracted much attention.Sox family members play important roles in immune regulation, for example，Sox2 and Sox9 play important regulatory roles in infection and autoimmunity. However, in SCII and spinal cord inflammation, there is no related research about Sox family molecules in the regulation. Hence, in a mouse model of SCII,we investigated the expression of Sox family member in microglia and found that the expression of Sox4 was the most significantly increased. Through the construction of Sox4 gene conditional knockout mice, we found that macrophages with Sox4 knockout significantly attenuated inflammation of spinal cord and SCII progression, while neurons and astrocytes with Sox4 knock out do not show obvious effect. Therefore, we intend to investigate Sox4 in the regulation of microglial activation and the production of inflammatory cytokines in the spinal cord and its influence on the progression of inflammation and SCII. This study will put forward a new mechanism for SCII development and suggest a new direction for its therapy.

脊髓缺血再灌注损伤（SCII）致残、致死率高，其发生发展的调控机制是该领域重大科学问题。小胶质细胞活化和炎症因子表达引起的炎症反应是其进展的关键因素，其中TLRs信号通路激活是其始动因素，其活化的分子调控机制目前广受关注。Sox家族分子在免疫调节中发挥重要作用，如Sox2在感染免疫、Sox9在自体免疫中发挥重要调控作用。但是，在SCII进展和脊髓炎症调控中，目前尚无Sox家族分子的相关研究报道。据此，我们在SCII小鼠模型小胶质细胞中，系统检测了Sox家族分子表达，发现Sox4表达显著升高。通过构建Sox4条件性基因敲除小鼠，我们发现巨噬细胞Sox4敲除显著减轻了脊髓炎症和SCII进展，而神经元和星形胶质细胞Sox4敲除无明显影响。因此，本研究拟探求Sox4在小胶质细胞活化和炎症因子表达中的调控作用与分子机制，及其对SCII发生进展的影响，以期为SCII提出新机制，为其治疗提供新方向。

脊髓损伤的致残、致死率高，一直是医学界的世界性难题，而脊髓缺血再灌注损伤是脊髓损伤过程中常见的病因及病理过程之一，也是脊髓损伤治疗的重要着眼点，但因为其病理生理过程复杂，机制繁多，目前临床针对缺血再灌注损伤的各种治疗方法都不令人满意。前期的临床研究显示，炎症因子在脊髓损伤过程中发挥重要作用，特别是SOX家族与脊髓损伤密切相关。在本研究中，我们通过构建脂多糖LPS诱导脊髓损伤体外细胞增殖与凋零模型，运用CCK-8法、流式细胞术和ELISA实验等发现过表达的SOX4可促进脊髓损伤的神经细胞增殖、抑制凋亡和炎症反应。通过检测差异表达的基因及STRING database、Cytoscape (ClueGO) 和KEGG分析发现，SOX4通过IL-17和TNF信号通路在脊髓损伤炎症调控中发挥重要作用，其可以缓解脂多糖诱导的脊髓损伤炎症和小胶质细胞死亡。同时我们在构建小鼠脊髓损伤动物模型中，发现通过吸入高浓度氢气可以保护小鼠免受脊髓损伤，可以明显改善脊髓损伤后的神经运动功能，这一过程也有可能与SOX4所参与的通路有关。综上所述，SOX4过表达可以有效促进脊髓损伤后神经细胞的增殖、抑制细胞凋亡，同时减轻脊髓损伤后的验证反应，为临床上脊髓损伤的治疗提供了新的治疗靶点。