Yenihayat Fatih, Altıntaş Özgül, Kasap Murat, Akpınar Gürler, Güzel Nil, Çelik Onur Sinan
Department of Ophthalmology, Kocaeli State Hospital, 41100, Kocaeli, Turkey.
Department of Ophthalmology, Medical School, Acıbadem University, Istanbul, Turkey.
Int Ophthalmol. 2018 Oct;38(5):1895-1905. doi: 10.1007/s10792-017-0672-6. Epub 2017 Aug 7.
To elucidate the metabolic processes playing roles in the formation of keratoconus (KC).
Tears samples were collected using capillary glass tubes without stimulation and without prior anesthesia from 17 patients and 16 controls. Proteomic analysis by fluorescent 2D gel electrophoresis (DIGE) coupled with MALDI-TOF/TOF was performed. The identified proteins that were differentially regulated were subjected to Ingenuity Pathway Analysis (IPA). Corneal topography analyses with Sirius topography system (Costruzioni Strumenti Oftalmici, Florence, Italy) were performed on all participants. The steepest keratometry index was lower than 50 diopters in all keratoconus patients.
DIGE analysis showed changes in abundance of nine proteins. Six of these proteins, namely serum albumin, Keratin Type II Cytoskeletal 1, IgG gamma chain-1, GAPDH, alpha-1 antitrypsin and ApoA-I, were down-regulated in the KC samples in comparison with the controls. In addition, we detected up-regulation of lysozyme C, keratin type I cytoskeletal 10 and lipocalin. The subsequent IPA predicted that NADH repair pathway is activated in the KC patients. This pathway involves generation of NADHX as a by-product via catalysis by GAPDH. NADHX is an inhibitor of several dehydrogenases and must be removed.
The involvement of NADHX repair pathway in KC should be investigated, since preliminary clues obtained in this study point to that direction. In particular, showing the presence of ATP-dependent NAD(P)H-hydrate dehydratase that eliminates NADHX would strengthen our findings and would be a major step toward understanding KC.
阐明在圆锥角膜（KC）形成过程中发挥作用的代谢过程。
使用毛细管玻璃管在未刺激且未预先麻醉的情况下，从17例患者和16名对照者中收集泪液样本。采用荧光二维凝胶电泳（DIGE）结合基质辅助激光解吸电离飞行时间串联质谱（MALDI-TOF/TOF）进行蛋白质组学分析。对鉴定出的差异调节蛋白进行Ingenuity通路分析（IPA）。使用Sirius角膜地形图系统（意大利佛罗伦萨的Costruzioni Strumenti Oftalmici公司）对所有参与者进行角膜地形图分析。所有圆锥角膜患者的最陡角膜曲率指数均低于50屈光度。
DIGE分析显示9种蛋白质丰度发生变化。与对照组相比，其中6种蛋白质，即血清白蛋白、角蛋白II型细胞骨架1、IgGγ链-1、甘油醛-3-磷酸脱氢酶（GAPDH）、α-1抗胰蛋白酶和载脂蛋白A-I，在KC样本中表达下调。此外，我们检测到溶菌酶C、角蛋白I型细胞骨架10和脂质运载蛋白上调。随后的IPA预测KC患者中NADH修复途径被激活。该途径涉及通过GAPDH催化产生副产物NADHX。NADHX是几种脱氢酶的抑制剂，必须被清除。
鉴于本研究获得的初步线索指向该方向，应研究NADHX修复途径在KC中的作用。特别是，证明存在消除NADHX的ATP依赖性NAD(P)H-水合物脱水酶将加强我们的发现，并将是迈向理解KC的重要一步。
