title: Retinoid Induces the Degradation of Corneodesmosomes and Downregulation of Corneodesmosomal Cadherins: Implications on the Mechanism of Retinoid-induced Desquamation.
abstract: BACKGROUND
  Topical retinoids induce skin fragility. As corneodesmosomes are important adhesion structures in the epidermal cohesion, an effect of retinoids on corneodesmosomes has been suspected.
  
  
  OBJECTIVE
  The aim of this study was to investigate the effect of retinoid on the expression of corneodesmosomal components including desmoglein (DSG) 1, desmocollin (DSC) 1, corneodesmosin (CDSN) and kallikrein (KLK)s.
  
  
  METHODS
  2% all-trans-retinol or ethanol was applied to the back of hairless mice for five days, and the structure of the stratum corneum was examined by transmission electron microscopy. The cultured human keratinocytes were treated with all-trans-retinoic acid (RA) in low or high calcium media for 24 hours.
  
  
  RESULTS
  Topical retinol increased corneocyte detachment and degradation of corneodesmosomes. RA significantly decreased DSG1 and DSC1 expression at the mRNA and protein levels in keratinocytes that were cultured in both low- and high-calcium media. On the other hand, CDSN mRNA levels did not decrease in low-calcium media or increase in high-calcium media after RA treatment. KLK5 and KLK7 expression did not increase after RA treatment.
  
  
  CONCLUSIONS
  Our results indicate that DSG1 and DSC1 downregulation by RA could be related to the increased degradation of corneodesmosomes and consequent desquamation induced by retinoids.
authors.affiliation: Department of Dermatology and Cutaneous Biology Research Institute, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Moon Young
authors.initials: MY
authors.lastname: Kim
authors.forename: Sang Eun
authors.initials: SE
authors.lastname: Lee
authors.forename: Jae Yong
authors.initials: JY
authors.lastname: Chang
authors.forename: Soo-Chan
authors.initials: SC
authors.lastname: Kim