Sustained serine proteases activity by prolonged increase in pH leads to degradation of lipid processing enzymes and profound alterations of barrier function and stratum corneum integrity
Sustained serine proteases activity by prolonged increase in pH leads to degradation of lipid processing enzymes and profound alterations of barrier function and stratum corneum integrity
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DOI：
10.1111/j.0022-202x.2005.23838.x
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发表时间：
2005-09-01
影响因子：
6.5
通讯作者：
Elias, PM
中科院分区：
文献类型：
--
作者：
Hachem, JP;Man, MQ;Elias, PM
我们最近发现，角质层（SC）pH值的短期增加伴随着渗透性屏障稳态和SC完整性/凝聚力的微小变化。由于延长的SC中和更接近地反映临床情况（即，新生儿皮肤，职业性皮炎条件），我们在此评估了通过长期应用1，1，3，3-四甲基胍超强碱而持续升高SC pH是否引起SC功能的显著改变。持续的SC中和不仅改变屏障恢复动力学，而且改变基础渗透屏障功能。这些异常可归因于β-葡糖脑苷脂酶（β-GlcCer 'ase）和酸性鞘磷脂酶（aSMase）催化活性的降低以及pH诱导的持续丝氨酸蛋白酶（SP）活性导致的酶降解。SP在这一过程中的作用是通过共同应用的SP抑制剂（SPI）的酶活性/含量的标准化。为了解决脂质加工酶是否是角质层胰凝乳蛋白酶（SCCE）的潜在底物，将来自人SC的蛋白质提取物在37 ℃下用重组活性SCCE在pH 7.2下处理2小时。与在不存在活性SCCE的情况下进行的对照实验相比，重组SCCE诱导β-GlcCer '酶或aSM酶的免疫印迹显著降低。最后，随着持续的SC中和，SC完整性/凝聚力恶化，归因于SP介导的角蛋白桥粒（CD）以及CD组成蛋白，桥粒芯糖蛋白1的降解。这些异常再次逆转共同应用SPI。总之，长时间的SC中和引起SC功能的严重异常，这是由于pH诱导的高SP活性，进而降解脂质加工酶和CD蛋白。
We showed recently that short-term increases in stratum corneum (SC) pH are accompanied by minor alterations in permeability barrier homeostasis and SC integrity/cohesion. Since prolonged SC neutralization more closely mirrors clinical situations (i.e., neonatal skin, occupational dermatitis conditions), we assessed here whether sustained elevations of SC pH by long-term application of 1,1,3,3-tetramethylguanidine superbase provoke profound alterations in SC function. Sustained SC neutralization altered not only barrier recovery kinetics but also basal permeability barrier function. These abnormalities were attributable to a decrease in beta-glucocerebrosidase (beta-GlcCer'ase) and acidic sphingomyelinase (aSMase) catalytic activity and enzyme degradation consequent to a pH-induced sustained serine protease (SP) activity. The role of SP in this process was shown by the normalization of enzyme activities/content by co-applied SP inhibitors (SPI). To address whether lipid-processing enzymes are potential substrates for the stratum corneum chymotryptic enzyme (SCCE), protein extracts from human SC were treated for 2 h at 37 degrees C with recombinant active SCCE at pH 7.2. Recombinant SCCE induced a significant decrease in the immunoblotting of both beta-GlcCer'ase or aSMase compared with control experiments performed in the absence of the active SCCE. Finally, with sustained SC neutralization, SC integrity/cohesion deteriorated, attributable to SP-mediated degradation of corneodesmosomes (CD) as well as CD constituent proteins, desmoglein 1. These abnormalities were again reversed by co-applied SPI. In conclusion, prolonged SC neutralization provokes profound abnormalities in SC function, due to pH-induced high SP activity that, in turn, degrades lipid processing enzymes and CD proteins.