Division of Molecular Therapy, UCL Institute of Ophthalmology, University of London, London, United Kingdom.
Invest Ophthalmol Vis Sci. 2011 Jun 23;52(7):4459-66. doi: 10.1167/iovs.10-6678.
To evaluate the potential role of the matrix metalloproteinase (MMP) system of Bruch's membrane in the pathology of age-related macular degeneration.
Free and bound pools of gelatinase activity in Bruch's membrane-choroid preparations were isolated by phosphate-buffered saline (PBS) and sodium dodecyl sulfate (SDS) extraction, respectively. Individual MMP species were separated by gelatin-substrate zymography and the levels were quantified by densitometric techniques. Altogether, 13 control (age range, 71-99 years) and 6 AMD (age range, 71-95 years) donor eyes were used.
All the gelatinase components normally present in control samples were also present in AMD tissue without any significant differences in their molecular masses. Total levels (bound plus free) of active MMP2 and -9 were significantly reduced in AMD donors (P < 0.05). The decrease in active MMP2 may be attributable to a similar reduction in the level of free pro-MMP2, the precursor to the active form. Reduction in active MMP9 occurred despite a nearly 3.5-fold increase in free pro-MMP9. The high-molecular-mass gelatinases denoted by HMW1 and -2 and comprising homo- and heteropolymers of pro-MMP2 and -9 were also raised in AMD (P < 0.05). The sequestration of free pro-MMP2 and -9 by these high-molecular-mass complexes may further contribute to reduced rates of activation of MMPs.
The reduction in the levels of activated MMP2 and -9 may be responsible for impaired matrix degradation of Bruch's membrane, leading to the pathology associated with AMD. The degradation pathway is therefore a viable therapeutic target for future intervention.
评估布鲁赫膜基质金属蛋白酶（MMP）系统在年龄相关性黄斑变性发病机制中的潜在作用。
通过磷酸盐缓冲盐水（PBS）和十二烷基硫酸钠（SDS）提取，分别分离布鲁赫膜-脉络膜制备物中的明胶酶活性的游离和结合池。通过明胶底物酶谱法分离各个 MMP 种类，并通过密度测定技术定量其水平。共使用 13 个对照（年龄范围 71-99 岁）和 6 个 AMD（年龄范围 71-95 岁）供体眼。
所有在对照样本中正常存在的明胶酶成分也存在于 AMD 组织中，其分子量没有任何显著差异。AMD 供体中活性 MMP2 和 -9 的总水平（游离加结合）显著降低（P<0.05）。活性 MMP2 的减少可能归因于游离 pro-MMP2 水平的类似降低，后者是活性形式的前体。尽管自由 pro-MMP9 增加了近 3.5 倍，但活性 MMP9 仍减少。由 pro-MMP2 和 -9 的同源和异源聚合物组成的高相对分子质量明胶酶 HMW1 和 -2 也在 AMD 中升高（P<0.05）。这些高分子量复合物对游离 pro-MMP2 和 -9 的隔离可能进一步导致 MMP 激活率降低。
活性 MMP2 和 -9 水平的降低可能导致布鲁赫膜基质降解受损，导致与 AMD 相关的病理学。因此，降解途径是未来干预的可行治疗靶点。
