Chen Ying, Jester James V, Anderson David M, Marchitti Satori A, Schey Kevin L, Thompson David C, Vasiliou Vasilis
Department of Environmental Health Sciences, Yale School of Public Health, New Haven, CT, 06521, USA.
Department of Ophthalmology, University of California-Irvine, Irvine, CA, 92697, USA.
Chem Biol Interact. 2017 Oct 1;276:9-14. doi: 10.1016/j.cbi.2016.12.017. Epub 2016 Dec 27.
ALDH3A1 is a corneal crystallin that protects ocular tissues from ultraviolet radiation through catalytic and non-catalytic functions. In addition, ALDH3A1 plays a functional role in corneal epithelial homeostasis by simultaneously modulating proliferation and differentiation. We have previously shown that Aldh3a1 knockout mice in a C57B6/129sV mixed genetic background develop lens cataracts. In the current study, we evaluated the corneal phenotype of Aldh3a1 knockout mice bred into a C57B/6J congenic background (KO). In vivo confocal microscopy examination of KO and wild-type (WT) corneas revealed KO mice to exhibit corneal haze, manifesting marked light scattering from corneal stroma. This corneal phenotype was further characterized by Imaging Mass Spectrometry (IMS) with spatial resolution that revealed a trilayer structure based on differential lipid localization. In these preliminary studies, no differences were observed in lipid profiles from KO relative to WT mice; however, changes in protein profiles of acyl-CoA binding protein (m/z 9966) and histone H4.4 (m/z 11308) were found to be increased in the corneal epithelial layer of KO mice. This is the first study to use IMS to characterize endogenous proteins and lipids in corneal tissue and to molecularly explore the corneal haze phenotype. Taken together, the current study presents the first genetic animal model of cellular-induced corneal haze due to the loss of a corneal crystallin, and strongly supports the notion that ALDH3A1 is critical to cellular transparency. Finally, IMS represents a valuable new approach to reveal molecular changes underlying corneal disease.
醛脱氢酶3A1（ALDH3A1）是一种角膜晶状体蛋白，通过催化和非催化功能保护眼组织免受紫外线辐射。此外，ALDH3A1通过同时调节增殖和分化在角膜上皮稳态中发挥功能作用。我们之前已经表明，在C57B6/129sV混合遗传背景下的Aldh3a1基因敲除小鼠会发生晶状体白内障。在当前研究中，我们评估了培育到C57B/6J同源背景（KO）中的Aldh3a1基因敲除小鼠的角膜表型。对KO和野生型（WT）角膜进行体内共聚焦显微镜检查发现，KO小鼠表现出角膜混浊，角膜基质出现明显的光散射。通过具有空间分辨率的成像质谱（IMS）对这种角膜表型进行进一步表征，结果显示基于脂质定位差异呈现出三层结构。在这些初步研究中，未观察到KO小鼠与WT小鼠在脂质谱方面存在差异；然而，发现酰基辅酶A结合蛋白（质荷比9966）和组蛋白H4.4（质荷比11308）的蛋白质谱在KO小鼠的角膜上皮层中有所增加。这是首次使用IMS对角膜组织中的内源性蛋白质和脂质进行表征，并从分子层面探究角膜混浊表型的研究。综上所述，当前研究呈现了首个因角膜晶状体蛋白缺失导致细胞诱导性角膜混浊的遗传动物模型，并有力支持了ALDH3A1对细胞透明度至关重要这一观点。最后，IMS代表了一种揭示角膜疾病潜在分子变化的有价值的新方法。
