Persa Cristina, Osmotherly Kaila, Chao-Wei Chen Kate, Moon Sungchur, Lou Marjorie F
Department of Veterinary and Biomedical Sciences, University of Nebraska-Lincoln, 134 VBS, 68583-0905, USA.
Exp Eye Res. 2006 Oct;83(4):817-23. doi: 10.1016/j.exer.2006.04.001. Epub 2006 Jun 12.
Clinical abnormalities in cystathionine-beta-synthase (CBS) deficiency, a key enzyme in the trans-sulfuration pathway, associate with many eye disorders. However, little is known about this enzyme in the eye. The goal of this study is to examine the distribution of CBS in the various regions of the eye, including conjunctiva, cornea, iris, lens, vitreous, retina and optic nerve using fresh eyes from both pigs (6 months) and humans (4-82 years). We have found that pig eye showed the highest CBS protein presence in cornea, conjunctiva and iris, followed by retina and optic nerve. The whole lens had a relatively lower amount and vitreous body had none. CBS protein distribution in the human eyes showed a similar pattern, with high level in the anterior segments but much lower amount in retina and optic nerve. CBS in anterior segments remained high throughout the lifespan, but retinal CBS showed a trend of age-dependent increase. The presence of CBS in human and pig eye tissues was further confirmed by RT-PCR, CBS activity assay, both showed similar distribution profiles as the Western blot analysis. This is the first evidence of the presence of CBS enzyme in the eye outside of the lens, which indicates that a functional trans-sulfuration pathway may be present in various eye tissues.
胱硫醚-β-合酶（CBS）是转硫途径中的关键酶，其缺乏所致的临床异常与多种眼部疾病相关。然而，人们对眼部的这种酶知之甚少。本研究的目的是利用来自猪（6个月）和人类（4至82岁）的新鲜眼睛，检测CBS在眼部各个区域，包括结膜、角膜、虹膜、晶状体、玻璃体、视网膜和视神经中的分布。我们发现猪眼中CBS蛋白在角膜、结膜和虹膜中的含量最高，其次是视网膜和视神经。整个晶状体中的含量相对较低，玻璃体中则没有。人眼中CBS蛋白的分布呈现相似模式，在前节含量较高，但在视网膜和视神经中含量低得多。前节中的CBS在整个生命周期中都保持较高水平，但视网膜中的CBS呈现出随年龄增长而增加的趋势。通过RT-PCR和CBS活性测定进一步证实了CBS在人和猪眼组织中的存在，两者均显示出与蛋白质印迹分析相似的分布情况。这是首次证明晶状体以外的眼部组织中存在CBS酶，这表明各种眼组织中可能存在功能性转硫途径。
