Cathepsin D repairing role in photodamaged skin barrier.
BACKGROUNDS/OBJECTIVES: Cathepsin D plays an important part in maintaining a normal skin barrier. Our previous study found that cathepsin D decreased in chronic photodamaged skin. This study investigated the cathepsin D content change in the stratum corneum (SC) and the repairing role of cathepsin D in chronic photodamaged skin barrier via the application of cathepsin D gel.


METHODS
Cathepsin D gel (0.001%) was applied to chronic photodamaged (sun-exposed forearm) human skin on identical sites (1 cm(2)/area) twice daily for 2 weeks. At 30 min and at 1, 3, 7, and 14 days, skin hydration and transepidermal water loss (TEWL) average values were detected via noninvasive skin detection equipment. Cathepsin D and transglutaminase (TGase)-1 in the skin sublayers were separated and detected via tape stripping, ELISA and Western blot.


RESULTS
After 2 weeks of cathepsin D gel application, the skin moisture value increased from 86.8 ± 1.2 to 95.2 ± 2.7 (p < 0.05), while TEWL decreased from 17.88 ± 1.87 to 11.58 ± 2.14 (p < 0.05). Cathepsin D protein was detected in the upper epidermis (12.6 ± 2.6 ng/cm(2)), mid-epidermis (8.4 ± 0.8 ng/cm(2)) and deep epidermis (16.2 ± 2.6 ng/cm(2)) in the cathepsin D gel group compared to the control group (2.2 ± 0.7, 3.0 ± 1.1 and 3.85 ± 1.4 ng/cm(2), respectively; p < 0.05). TGase-1 enzyme expression was upregulated 2.54 ± 0.19 times in the matrix gel-treated skin.


CONCLUSIONS
These data suggest that cathepsin D gel could increase the SC cathepsin D content and repair the epidermal barrier in chronic photodamaged skin. The mechanism might be related to increasing TGase-1 expression and activity.
Department of Dermato-Venereology, Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, PR China.
Yue
Y
Zheng
Haiyan
H
Chen
Wei
W
Lai
Qingfang
Q
Xu
Chen
C
Liu
Lin
L
Wu
Howard I
HI
Maibach
D000279:Administration, Cutaneous; D002402:Cathepsin D / Q000008:administration & dosage* / Q000378:metabolism; D005260:Female; D005782:Gels; D006801:Humans; D008297:Male; D008875:Middle Aged; D012038:Regeneration / Q000187:drug effects*; D012867:Skin / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology / Q000528:radiation effects; D015595:Skin Aging / Q000187:drug effects*; D013997:Time Factors; D011503:Transglutaminases / Q000378:metabolism; D016896:Treatment Outcome; D014466:Ultraviolet Rays; D014867:Water / Q000378:metabolism; D014870:Water Loss, Insensible / Q000187:drug effects
D005782:Gels; D014867:Water; D011503:Transglutaminases; C105804:transglutaminase 1; D002402:Cathepsin D