Molecular Toxicology and Environmental Health Sciences Program, Department of Pharmaceutical Sciences, University of Colorado AMC, Aurora, CO 80045, USA.
Free Radic Biol Med. 2012 May 1;52(9):1937-44. doi: 10.1016/j.freeradbiomed.2012.02.050. Epub 2012 Mar 8.
Evidence suggests that aldehydic molecules generated during lipid peroxidation (LPO) are causally involved in most pathophysiological processes associated with oxidative stress. 4-Hydroxy-2-nonenal (4-HNE), the LPO-derived product, is believed to be responsible for much of the cytotoxicity. To counteract the adverse effects of this aldehyde, many tissues have evolved cellular defense mechanisms, which include the aldehyde dehydrogenases (ALDHs). Our laboratory has previously characterized the tissue distribution and metabolic functions of ALDHs, including ALDH3A1, and demonstrated that these enzymes may play a significant role in protecting cells against 4-HNE. To further characterize the role of ALDH3A1 in the oxidative stress response, a rabbit corneal keratocyte cell line (TRK43) was stably transfected to overexpress human ALDH3A1. These cells were studied after treatment with 4-HNE to determine their abilities to: (a) maintain cell viability, (b) metabolize 4-HNE and its glutathione conjugate, (c) prevent 4-HNE-protein adduct formation, (d) prevent apoptosis, (e) maintain glutathione homeostasis, and (f) preserve proteasome function. The results demonstrated a protective role for ALDH3A1 against 4-HNE. Cell viability assays, morphological evaluations, and Western blot analyses of 4-HNE-adducted proteins revealed that ALDH3A1 expression protected cells from the adverse effects of 4-HNE. Based on the present results, it is apparent that ALDH3A1 provides exceptional protection from the adverse effects of pathophysiological concentrations of 4-HNE such as may occur during periods of oxidative stress.
有证据表明，脂质过氧化（LPO）过程中产生的醛类分子与氧化应激相关的大多数病理生理过程有关。LPO 衍生产物 4-羟基-2-壬烯醛（4-HNE）被认为是导致大部分细胞毒性的主要原因。为了抵消这种醛的不良影响，许多组织已经进化出细胞防御机制，其中包括醛脱氢酶（ALDHs）。我们实验室之前已经对 ALDHs 的组织分布和代谢功能进行了特征描述，包括 ALDH3A1，并证明这些酶可能在保护细胞免受 4-HNE 侵害方面发挥重要作用。为了进一步阐明 ALDH3A1 在氧化应激反应中的作用，我们使用兔角膜成纤维细胞系（TRK43）稳定转染过表达人 ALDH3A1。用 4-HNE 处理这些细胞后，研究它们的以下能力：（a）维持细胞活力，（b）代谢 4-HNE 及其谷胱甘肽缀合物，（c）防止 4-HNE-蛋白质加合物的形成，（d）防止细胞凋亡，（e）维持谷胱甘肽的体内平衡，（f）保持蛋白酶体功能。结果表明，ALDH3A1 在对抗 4-HNE 方面具有保护作用。细胞活力测定、形态评估和 4-HNE 加合物蛋白的 Western blot 分析表明，ALDH3A1 表达可保护细胞免受 4-HNE 的不良影响。根据目前的结果，ALDH3A1 显然为细胞提供了对病理生理浓度 4-HNE 的不良影响的特殊保护，例如在氧化应激期间可能发生的情况。
