title: Changes of cathepsin B in human photoaging skin both in vivo and in vitro.
abstract: BACKGROUND
  Cathepsin B plays an important role in cell cycle, extracellular matrix changes and cutaneous tumorigenesis: whether it plays a role in photoaged skin remains unknown. This study aimed to investigate the role of cathepsin B in skin photoaging in vivo and in vitro.
  
  
  METHODS
  The expressions of cathepsin B were compared with immunohistochemical methods in solar exposed skin and solar protected skin of six healthy Chinese volunteers. The mRNA and protein expression of cathepsin B in ultraviolet light A (UVA) induced premature senescence fibroblasts in vitro were detected by real-time reverse transcription polymerase chain reaction (RT-PCR) and Western blotting technique.
  
  
  RESULTS
  Decreased expression of cathepsin B was observed in photoaged skin compared with that of the solar protected skin. In the UVA induced, premature senescence fibroblasts, a lower expression of cathepsin B was detected by Western blotting and a decreased synthesis of cathepsin B mRNA in the same cells was revealed by real-time RT-PCR.
  
  
  CONCLUSIONS
  The results demonstrated a significant negative correlation between skin photoaging and cathepsin B in vitro and in vivo. We propose that cathepsin B, besides matrix metalloproteinases and antioxidant enzymes, is involved in the process of skin photoaging in that it contributes to extracellular matrix remodelling and is a dominant protease in cellular apoptosis and senescence.
authors.affiliation: Department of Dermatovenereology, Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong 510630, China. drlaiwei@163.com
authors.forename: Wei
authors.initials: W
authors.lastname: Lai
authors.forename: Yue
authors.initials: Y
authors.lastname: Zheng
authors.forename: Zhang-zhang
authors.initials: ZZ
authors.lastname: Ye
authors.forename: Xiang-yang
authors.initials: XY
authors.lastname: Su
authors.forename: Miao-jian
authors.initials: MJ
authors.lastname: Wan
authors.forename: Zi-jian
authors.initials: ZJ
authors.lastname: Gong
authors.forename: Xiao-yuan
authors.initials: XY
authors.lastname: Xie
authors.forename: Wei
authors.initials: W
authors.lastname: Liu
mesh_terms: D015153:Blotting, Western; D002401:Cathepsin B / Q000032:analysis / Q000235:genetics / Q000502:physiology*; D005260:Female; D005347:Fibroblasts / Q000528:radiation effects; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D012867:Skin / Q000528:radiation effects*; D015595:Skin Aging; D014466:Ultraviolet Rays; D001616:beta-Galactosidase / Q000032:analysis
chemical_list: D001616:beta-Galactosidase; D002401:Cathepsin B