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

J Invest Dermatol. 2005 Sep;125(3):510-20. doi: 10.1111/j.0022-202X.2005.23838.x.


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.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Catalysis
  • Epidermis / drug effects
  • Epidermis / enzymology
  • Epidermis / metabolism*
  • Glucosylceramidase / metabolism*
  • Guanidines / pharmacology
  • Humans
  • Hydrogen-Ion Concentration
  • Kallikreins / drug effects
  • Kallikreins / metabolism*
  • Lipid Metabolism
  • Male
  • Mice
  • Mice, Hairless
  • Recombinant Proteins
  • Serine Endopeptidases / drug effects
  • Serine Endopeptidases / metabolism*
  • Serine Proteinase Inhibitors / pharmacology
  • Sphingomyelin Phosphodiesterase / metabolism*


  • Guanidines
  • Recombinant Proteins
  • Serine Proteinase Inhibitors
  • Sphingomyelin Phosphodiesterase
  • Glucosylceramidase
  • Kallikreins
  • Klk7 protein, mouse
  • Serine Endopeptidases
  • 1,1,3,3-tetramethylguanidine