LncRNA Gm15628介导的单核细胞来源巨噬细胞极化状态在缺血性卒中脑损伤中的作用研究

Recently, the neuroinflammation induced by monocyte-derived macrophages (MoDMs) is the hotspot in the field of stroke. MoDMs are known to polarize into pro-inflammatory（M1）and anti-inflammatory(M2) phenotypes, which promote and inhibit brain injury, respectively. However, the mechanisms in the transition between M1 and M2 phenotypes are unclear. Our preliminary studies found that the expression of lncRNA Gm15628 was significantly increased in M1 but reduced in M2 MoDMs. We further used a synthetic RNA (siRNA) to downregulate the expression of lncRNA Gm15628 in M1 MoDMs, and found that the expression of pro-inflammatory gene was attenuated while anti-inflammatory gene expression was promoted, suggesting a strong correlation between lncRNA Gm15628 expression and MoDMs polarization. Therefore, this project will applied the model of middle cerebral artery occlusion (MCAO)-induced cerebral ischemic stroke to study the correlation between lncRNA Gm15628 and MoDMs polarization. The role of lncRNA Gm15628 in in ischemia-induced cerebral injuries will be systematically explored by using the techniques of behavioral test, RT-qPCR, immunohistochemistry, Elisa and fluorescence-activated cell sorting (FCAS). The achievements of this study will enrich our understanding of the mechanism of MoDMs polarization and its role in cerebral ischemic injuries, which may provide the experimental evidence for treatment of ischemic stroke in clinic.

近年来，单核细胞来源巨噬细胞(MoDMs)诱导的神经炎症成为脑卒中研究的热点。MoDMs在卒中后分化成促炎型(M1)和抗炎型(M2)，分别加剧和减轻脑缺血损伤，但其调节机制尚不明确。我们前期研究发现，长链非编码RNA(lncRNA)Gm15628在缺血脑组织M1型MoDMs内表达增加，在M2型内表达降低；抑制M1型MoDMs内Gm15628的表达可降低促炎性基因表达，而增强抗炎性基因表达，提示：lncRNA Gm15628可能通过调节MoDMs的极化状态参与卒中后的脑损伤过程。本课题拟利用小鼠脑中动脉阻塞(MCAO)缺血性卒中模型，借助行为学、RT-qPCR、免疫组织化学、Elisa和流式细胞术等技术，明确lncRNA Gm15628和卒中后脑组织MoDMs极化状态的关系及其在脑缺血损伤过程中的作用。研究成果将丰富人们对卒中后MoDMs极化状态调节机制的认识，有望为卒中的治疗提供实验依据。

近年来，单核细胞来源巨噬细胞(MoDMs)诱导的神经炎症成为脑卒中研究的热点。以往研究提示MoDMs在卒中后可以分化成促炎型(M1)和抗炎型(M2)，分别加剧和减轻脑缺血损伤，但其具体分子机制尚不明确。本项目我们从三个方面进行相关的研究：(1)系统分析卒中后缺血脑组织MoDMs和MiDMs内炎性反应基因及lncRNA Gm15628的表达情况；(2)研究卒中后缺血脑组织MoDMs内lncRNA Gm15628水平和M1-M2型MoDMs极化状态的关系；(3)进一步明确lncRNA Gm15628在卒中小鼠脑缺血损伤的作用。我们的研究结果提示：(1)小鼠大脑中动脉阻塞(MCAO)所致脑缺血损伤后增加缺血脑组织内lncRNA Gm15628的水平和 M1型标志物及相关转录因子基因和蛋白水平，并降低M2型标志物及相关转录因子基因和蛋白水平；(2)腹腔注射LPS增加卒中小鼠脑梗死体积、提高神经功能学评分，增加缺血脑组织内lncRNA Gm15628的水平和M1型标志物及相关转录因子基因和蛋白水平，并降低M2型标志物及相关转录因子基因和蛋白表达水平；而腹腔注射IL-4能够减轻脑梗死体积、降低神经功能学评分，降低缺血脑组织内 lncRNA Gm15628的水平和M1型标志物及相关转录因子基因和蛋白水平，并增加M2型标志物及相关转录因子基因和蛋白表达水平；(3)腹腔注射lncRNA Gm15628 siRNA能够减轻脑梗死体积和脑水肿，并降低神经功能学评分。研究成果将丰富人们对卒中后MoDMs极化状态调节机制的认识，并有望为卒中的治疗提供实验依据，具有重要的学术价值和潜在临床应用价值。