Zhao Lian, Zabel Matthew K, Wang Xu, Ma Wenxin, Shah Parth, Fariss Robert N, Qian Haohua, Parkhurst Christopher N, Gan Wen-Biao, Wong Wai T
Unit on Neuron-Glia Interactions in Retinal Disease, National Eye institute National Institutes of Health, Bethesda, MD, USA.
Biological Imaging Core, National Eye institute National Institutes of Health, Bethesda, MD, USA.
EMBO Mol Med. 2015 Sep;7(9):1179-97. doi: 10.15252/emmm.201505298.
Retinitis pigmentosa, caused predominantly by mutations in photoreceptor genes, currently lacks comprehensive treatment. We discover that retinal microglia contribute non-cell autonomously to rod photoreceptor degeneration by primary phagocytosis of living rods. Using rd10 mice, we found that the initiation of rod degeneration is accompanied by early infiltration of microglia, upregulation of phagocytic molecules in microglia, and presentation of "eat-me" signals on mutated rods. On live-cell imaging, infiltrating microglia interact dynamically with photoreceptors via motile processes and engage in rapid phagocytic engulfment of non-apoptotic rods. Microglial contribution to rod demise is evidenced by morphological and functional amelioration of photoreceptor degeneration following genetic ablation of retinal microglia. Molecular inhibition of microglial phagocytosis using the vitronectin receptor antagonist cRGD also improved morphological and functional parameters of degeneration. Our findings highlight primary microglial phagocytosis as a contributing mechanism underlying cell death in retinitis pigmentosa and implicate microglia as a potential cellular target for therapy.
视网膜色素变性主要由光感受器基因突变引起,目前缺乏全面的治疗方法。我们发现视网膜小胶质细胞通过对活视杆细胞的初级吞噬作用,非细胞自主地促进视杆细胞变性。利用rd10小鼠,我们发现视杆细胞变性的起始伴随着小胶质细胞的早期浸润、小胶质细胞中吞噬分子的上调以及突变视杆细胞上“吃我”信号的呈现。在活细胞成像中,浸润的小胶质细胞通过运动过程与光感受器动态相互作用,并对未凋亡的视杆细胞进行快速吞噬。视网膜小胶质细胞基因消融后光感受器变性的形态和功能改善证明了小胶质细胞对视杆细胞死亡的作用。使用玻连蛋白受体拮抗剂cRGD对小胶质细胞吞噬作用进行分子抑制也改善了变性的形态和功能参数。我们的研究结果突出了小胶质细胞的初级吞噬作用是视网膜色素变性细胞死亡的一个促成机制,并表明小胶质细胞是一个潜在的治疗细胞靶点。