PDF(Pubmed)
Abstract：
Perforin-mediated cytotoxicity plays a crucial role in microbial defense, tumor surveillance, and primary autoimmune disorders. However, the contribution of the cytolytic protein perforin to ischemia-induced secondary tissue damage in the brain has not been fully investigated. Here, we examined the kinetics and subpopulations of perforin-positive cells and then evaluated the direct effects of perforin-mediated cytotoxicity on outcomes after ischemic stroke. Using flow cytometry, we showed that perforin+CD45+ immune cells could be detected at 12 h and that the percentage of these cells increased largely until on day 3 and then significantly declined on day 7. Surprisingly, the percentage of Perforin+CD45+ cells also unexpectedly increased from day 7 to day 14 after ischemic stroke in Perforin1-EGFP transgenic mice. Our results suggested that Perforin+CD45+ cells play vital roles in the ischemic brain at early and late stages and further suggested that Perforin+CD45+ cells are a heterogeneous population. Surprisingly, in addition to CD8+ T cells, NK cells, and NKT cells, central nervous system (CNS)-resident immune microglia, which are first triggered and activated within minutes after ischemic stroke in mice, also secreted perforin during ischemic brain injury. In our study, the percentage of perforin+ microglia increased from 12 h after ischemic stroke, increased largely until on day 3 after ischemic stroke, and then moderately declined from days 3 to 7. Intriguingly, the percentage of perforin+ microglia also dramatically increased from days 7 to 14 after ischemic stroke. Furthermore, compared with wild-type littermates, Perforin 1-/- mice exhibited significant increases in the cerebral infarct volume, neurological deficits, and neurogenesis and inhibition of neurotoxic astrogliosis. Interestingly, the number of CD45+CD3+ T cells was significantly decreased in Perforin 1-/- mice compared with their wild-type littermates, especially the number of γδ T cells. In addition, Perforin 1-/- mice had lower levels of IL-17 than their wild-type littermates. Our results identified a critical function of perforin-mediated neurotoxicity in the ischemic brain, suggesting that targeting perforin-mediated neurotoxicity in brain-resident microglia and invading perforin+CD45+ immune cells may be a potential strategy for the treatment of ischemic stroke.
摘要：
穿孔素介导的细胞毒性在微生物防御中起着至关重要的作用,肿瘤监测,和原发性自身免疫性疾病。然而,细胞溶解蛋白穿孔素对缺血诱发的脑组织继发性损伤的作用尚未得到充分研究.这里,我们检测了穿孔素阳性细胞的动力学和亚群,然后评估了穿孔素介导的细胞毒性对缺血性卒中后结局的直接影响.使用流式细胞术，我们发现穿孔素+CD45+免疫细胞可以在12小时内检测到，这些细胞的百分比在第3天之前大幅增加，然后在第7天显着下降。令人惊讶的是,在穿孔素1-EGFP转基因小鼠中,穿孔素+CD45+细胞的百分比在缺血性中风后第7天至第14天也意外地增加。我们的结果表明，穿孔素CD45细胞在早期和晚期缺血性脑中起着至关重要的作用，并进一步表明穿孔素CD45细胞是异质群体。令人惊讶的是,除了CD8+T细胞，NK细胞,和NKT细胞，中枢神经系统（CNS）驻留的免疫小胶质细胞，在小鼠缺血性中风后几分钟内首次触发并激活，在缺血性脑损伤期间也分泌穿孔素。在我们的研究中,穿孔素+小胶质细胞的百分比从缺血性卒中后12小时增加，在缺血性中风后的第3天，然后从第3天到第7天适度下降。有趣的是，穿孔素+小胶质细胞的百分比在缺血性卒中后第7~14天也显著增加.此外，与野生型同窝相比，穿孔素1-/-小鼠显示脑梗死体积显著增加，神经功能缺损,以及神经发生和神经毒性星形胶质增生的抑制。有趣的是,与野生型同窝小鼠相比，Perforin1-/-小鼠的CD45+CD3+T细胞数量显着减少，尤其是γδT细胞的数量。此外,穿孔素1-/-小鼠的IL-17水平低于其野生型同窝。我们的结果确定了穿孔素介导的神经毒性在缺血性大脑中的关键功能，提示靶向穿孔素介导的脑内小胶质细胞神经毒性和侵入穿孔素+CD45+免疫细胞可能是治疗缺血性卒中的潜在策略.
