Hirao Tetsuji, Takahashi Motoji
Shiseido Life Science Research Center, 2-2-1 Hayabuchi, Tsuzuki-ku, Yokohama 224-8558, Japan.
FEBS Lett. 2005 Dec 19;579(30):6870-4. doi: 10.1016/j.febslet.2005.11.032. Epub 2005 Dec 1.
Stratum corneum (SC), the outermost layer of the skin, is continuously exposed to oxidative stress via sunlight, lipid peroxidation, and is subsequently accompanied by oxidative modification. Previous studies have shown that major oxidative target proteins in the SC are keratins. However, it remains unclear to date whether cornified envelopes (CEs), protein envelopes of the corneocytes (cornified cells), would be oxidized. In this study, we first revealed oxidative modification of CEs using labeled hydrazide derivatives to detect carbonyl moieties. Carbonylation of CEs was confirmed by reaction with monoclonal antibodies against aldehyde-bound proteins, including anti-acrolein, anti-crotonaldehyde, anti-4-hydroxy-2-nonenal. The extent of carbonylation is stronger in CEs from the face, a sun-exposed area, than those from the inside of upper arm, an unexposed area. Carbonylation of CEs did not depend on their maturity, as evaluated by loss of involucrin antigenicity during maturation process, suggesting that CEs are carbonylated regardless of their maturation stage.
角质层（SC）作为皮肤的最外层，持续暴露于因阳光、脂质过氧化作用产生的氧化应激中，随后会发生氧化修饰。先前的研究表明，角质层中主要的氧化靶蛋白是角蛋白。然而，迄今为止，角质形成细胞（角化细胞）的蛋白包膜——角质包膜（CEs）是否会被氧化仍不清楚。在本研究中，我们首先使用标记的酰肼衍生物检测羰基部分，揭示了角质包膜的氧化修饰。通过与抗醛结合蛋白的单克隆抗体（包括抗丙烯醛、抗巴豆醛、抗4-羟基-2-壬烯醛）反应，证实了角质包膜的羰基化。面部（阳光暴露区域）的角质包膜羰基化程度比上臂内侧（未暴露区域）的更强。角质包膜的羰基化并不取决于其成熟度，成熟过程中内披蛋白抗原性的丧失可评估成熟度，这表明无论角质包膜处于何种成熟阶段，都会发生羰基化。
