METHODS: To assess the effect of CSF1R signaling, we employed the CSF1R antagonist PLX5622 formulated in chow (PLX5622 diet, PD) and its control chow (control diet, CD). We examined the effect of PD in steady state and EAE by analyzing cells isolated from peripheral immune organs and from the CNS via flow cytometry. We determined CNS infiltration sites and assessed the extent of demyelination using immunohistochemistry of cerebella and spinal cords. Transcripts of genes associated with neuroinflammation were also analyzed in these tissues.
RESULTS: In addition to microglial depletion, PD treatment reduced dendritic cells and macrophages in peripheral immune organs, both during steady state and during EAE. Furthermore, CSF1R antagonism modulated numbers and relative frequencies of T effector cells both in the periphery and in the CNS during the early stages of the disease. Classical neurological symptoms were milder in PD compared to CD mice. Interestingly, a subset of PD mice developed atypical EAE symptoms. Unlike previous studies, we observed that the CNS of PD mice was infiltrated by increased numbers of peripheral immune cells compared to that of CD mice. Immunohistochemical analysis showed that CNS infiltrates in PD mice were mainly localized in the cerebellum while in CD mice infiltrates were primarily localized in the spinal cords during the onset of neurological deficits. Accordingly, during the same timepoint, cerebella of PD but not of CD mice had extensive demyelinating lesions, while spinal cords of CD but not of PD mice were heavily demyelinated.
CONCLUSIONS: Our findings suggest that CSF1R activity modulates the cellular composition of immune cells both in the periphery and within the CNS, and affects lesion localization during the early EAE stages.
方法:为了评估CSF1R信号的效果,我们采用了在食物中配制的CSF1R拮抗剂PLX5622(PLX5622饮食,PD)及其控制食物(控制饮食,CD)。我们通过流式细胞术分析从外周免疫器官和从CNS分离的细胞,检查了稳态和EAE中PD的作用。我们确定了中枢神经系统浸润部位,并使用小脑和脊髓的免疫组织化学评估了脱髓鞘的程度。还在这些组织中分析了与神经炎症相关的基因的转录物。
结果:除了小胶质细胞耗竭,PD治疗减少外周免疫器官中的树突状细胞和巨噬细胞,在稳态和EAE期间。此外,在疾病的早期阶段,CSF1R拮抗作用调节了外周和CNS中T效应细胞的数量和相对频率。与CD小鼠相比,PD中的经典神经系统症状较轻。有趣的是,一部分PD小鼠出现不典型的EAE症状.与以往的研究不同,我们观察到,与CD小鼠相比,PD小鼠的CNS浸润的外周免疫细胞数量增加。免疫组织化学分析表明,在神经功能缺损发作期间,PD小鼠的CNS浸润主要位于小脑中,而CD小鼠的浸润主要位于脊髓中。因此,在同一时间点,小脑的PD而不是CD小鼠有广泛的脱髓鞘病变,而CD而不是PD小鼠的脊髓严重脱髓鞘。
结论:我们的研究结果表明,CSF1R活性调节外周和中枢神经系统内免疫细胞的细胞组成,并影响早期EAE阶段的病变定位。