Division of Anatomy, Department of Surgery, University of Toronto, Toronto, Ontario, Canada.
Rehabilitation Science Institute, University of Toronto, Toronto, Ontario, Canada.
Invest Ophthalmol Vis Sci. 2019 Feb 1;60(2):634-649. doi: 10.1167/iovs.18-25257.
Integrin adherence to the extracellular matrix (ECM) is essential for retinal ganglion cell (RGC) survival: damage causes production and release of ECM degrading matrix metalloproteinases (MMPs) that disrupt integrin ligation, leading to RGC death. The interplay of MMPs, integrins, and focal adhesion kinase (FAK) was studied in RGCs after optic nerve injury.
Optic nerve transection and optic nerve crush were used to study RGC survival and regeneration, respectively. Treatments were administered intravitreally or into the cut end of the optic nerve. RGC survival was assessed by fluorescence or confocal microscopy; cell counting, peptide levels, and localization were assessed by Western blot and immunohistochemistry.
MMP-9 was most strongly increased and localized to RGCs after injury. Pan-MMP, MMP-2/-9, and MMP-3 inhibition all significantly enhanced RGC survival and increased RGC axon regeneration. FAK activation was decreased at 4 days postaxotomy, when apoptosis begins. FAK inhibition reduced RGC survival and abrogated the neuroprotective effects of MMP inhibition, whereas FAK activation increased RGC survival despite MMP activation. Integrin ligation with CD29 antibody or glycine-arginine-glycine-aspatate-serine (GRGDS) peptide increased RGC survival after axotomy.
ECM-integrin ligation promotes RGC survival and axon regeneration via FAK activation.
整合素与细胞外基质（ECM）的黏附对于视网膜神经节细胞（RGC）的存活至关重要：损伤会导致 ECM 降解基质金属蛋白酶（MMPs）的产生和释放，从而破坏整合素的连接，导致 RGC 死亡。本研究旨在探讨 MMPs、整合素和粘着斑激酶（FAK）在视神经损伤后的 RGC 中的相互作用。
视神经横断和视神经挤压分别用于研究 RGC 的存活和再生。通过玻璃体内或视神经切割端给药。通过荧光或共聚焦显微镜评估 RGC 存活；通过 Western blot 和免疫组织化学评估细胞计数、肽水平和定位。
MMP-9 在损伤后增加最多，并定位于 RGC 中。泛 MMP、MMP-2/-9 和 MMP-3 抑制均可显著增强 RGC 存活并增加 RGC 轴突再生。FAK 激活在轴突切断后 4 天（即开始凋亡时）降低。FAK 抑制降低了 RGC 的存活并消除了 MMP 抑制的神经保护作用，而 FAK 激活尽管 MMP 激活仍增加了 RGC 的存活。CD29 抗体或甘氨酸-精氨酸-甘氨酸-天冬氨酸-丝氨酸（GRGDS）肽与整合素的黏附可增加轴突切断后的 RGC 存活。
ECM-整合素黏附通过 FAK 激活促进 RGC 存活和轴突再生。
