Xie Jing, Li Yijian, Dai Jiaman, He Yan, Sun Dayu, Dai Chao, Xu Haiwei, Yin Zheng Qin
Southwest Eye Hospital, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, China.
Key Laboratory of Visual Damage, Regeneration and Restoration of Chongqing, Chongqing, China.
Front Cell Neurosci. 2019 Jul 25;13:341. doi: 10.3389/fncel.2019.00341. eCollection 2019.
The inflammatory microenvironment in the retina plays a vital role in the pathogenesis and progression of retinitis pigmentosa (RP). Microglial inflammatory cytokines production leads to gliosis and apoptosis of retinal neurons, and ultimately, visual loss. Cell-based therapies using grafted olfactory ensheathing cells (OECs) have demonstrated modulation of degenerative microenvironments in the central nervous system (CNS), in a number of animal models. However, mechanisms by which grafted OECs can reduce degeneration in the retina are not well understood. In the present study, we set up an OEC/BV2 microglia co-culture system, and an royal college of surgeons (RCS) rat model, used cell transplantation, immunohistochemistry, RT-PCR, western blot to explore the mechanisms by which OECs affect expression of pro- or anti-inflammatory cytokines and polarization of M(IL-6) and M(Arg1) type microglial activation in the retina. We found that compared with the LPS (Lipopolysaccharide) and olfactory nerve fibroblast (ONF), the OEC and BV2 co-culture group modulate microglial cytokines releasing toward the anti-inflammation, and away from the pro-inflammation, which was followed by higher IL-4 and IL-10 and lower TNF-a and IL-6 in their expression levels. , the transplantation group significantly reduced activated resident microglia/infiltrated macrophage, and expression of pro-inflammatory cytokines in RCS rats retina, increased anti-inflammatory cytokines in transplantation area. Additionally, we found that OECs expressed SOCS3 and down-regulated the JAK2/STAT3 (Janus Kinase 2/Signal Transducer and Activator of Transcription 3) pathway. Thirdly, OEC transplantation reduced Caspase-3 expression, protected inner retinal neurons and photoreceptors and therefore, delayed the visual function degeneration. In conclusion, our data suggest that OECs delay retinal degeneration in RP, at least in part through immunomodulation of microglia via the JAK/STAT pathway.
视网膜中的炎症微环境在色素性视网膜炎（RP）的发病机制和进展中起着至关重要的作用。小胶质细胞炎性细胞因子的产生会导致视网膜神经元的胶质增生和凋亡，最终导致视力丧失。在许多动物模型中，使用移植嗅鞘细胞（OECs）的细胞疗法已证明可调节中枢神经系统（CNS）中的退行性微环境。然而，移植的OECs能够减少视网膜退变的机制尚不清楚。在本研究中，我们建立了OEC/BV2小胶质细胞共培养系统和皇家外科学院（RCS）大鼠模型，采用细胞移植、免疫组织化学、RT-PCR、蛋白质印迹法来探究OECs影响视网膜中促炎或抗炎细胞因子表达以及M（IL-6）和M（Arg1）型小胶质细胞活化极化的机制。我们发现，与脂多糖（LPS）和嗅神经成纤维细胞（ONF）相比，OEC和BV2共培养组可调节小胶质细胞细胞因子向抗炎方向释放，远离促炎方向，其表达水平表现为IL-4和IL-10较高，而TNF-α和IL-6较低。此外，移植组显著减少了RCS大鼠视网膜中活化的常驻小胶质细胞/浸润巨噬细胞以及促炎细胞因子的表达，增加了移植区域的抗炎细胞因子。另外，我们发现OECs表达SOCS3并下调JAK2/STAT3（Janus激酶2/信号转导和转录激活因子3）通路。第三，OEC移植降低了Caspase-3的表达，保护了视网膜内层神经元和光感受器，因此延缓了视觉功能退变。总之，我们的数据表明，OECs至少部分通过JAK/STAT途径对小胶质细胞进行免疫调节，从而延缓RP中的视网膜退变。
