SFRP2 and slug contribute to cellular resistance to apoptosis in hypertrophic scars

PLoS One. 2012;7(12):e50229. doi: 10.1371/journal.pone.0050229. Epub 2012 Dec 4.

Abstract

Hypertrophic scars (HS) are skin disorders which occur after wounding and thermal injury. Our previous studies have suggested that secreted frizzled-related protein 2 (SFRP2) is involved in HS formation and that the suppression of SFRP2 promotes apoptosis of hypertrophic scar fibroblasts (HSFBs). However, the mechanisms have not been clarified. Previous studies revealed that Slug expression inhibits cell apoptosis, in vitro and in vivo, and SFRP2 regulates the expression of Slug in cervical cancer cells. In the present study, we quantified differential expression levels of expression of SFRP2 and Slug in HS and normal skin tissues by immunohistochemistry, both of which have important anti-apoptosis roles. Furthermore, a short hairpin RNA approach was adopted to investigate the potential function of SFRP2 and Slug in HSFB apoptosis. Cell apoptosis was detected using fluorescence-activated cell sorting and Caspase-3 activity was assayed by spectrophotometry. This study demonstrates that SFRP2 expression, as well as Slug, is dramatically up-regulated in HS relative to normal skin tissues, and the Slug expression is positively correlated with SFRP2. Slug expression was down-regulated in SFRP2-deficient cells, and the down-regulation of Slug expression increased sensitivity to apoptosis which was induced through a caspase-3-dependent pathway. The infected cells with reduced levels of Slug were tested for the expression of apoptosis-related genes (Bcl-2, Bax and PUMA) which were previously identified as Slug targets. Bcl-2 expression was down-regulated in Slug-deficient cells. In conclusion, SFRP2 appears to interact with Slug to affect the apoptosis of hypertrophic scar fibroblasts.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Apoptosis / physiology*
  • Base Sequence
  • Blotting, Western
  • Cell Line
  • Cicatrix, Hypertrophic / physiopathology*
  • DNA Primers
  • Flow Cytometry
  • Gene Silencing
  • Humans
  • Immunohistochemistry
  • Membrane Proteins / genetics
  • Membrane Proteins / physiology*
  • RNA, Small Interfering / genetics
  • Real-Time Polymerase Chain Reaction
  • Snail Family Transcription Factors
  • Transcription Factors / genetics
  • Transcription Factors / physiology*

Substances

  • DNA Primers
  • Membrane Proteins
  • RNA, Small Interfering
  • SFRP2 protein, human
  • SNAI1 protein, human
  • Snail Family Transcription Factors
  • Transcription Factors

Grants and funding

Experiments done for the manuscript revisions were supported by National Natural Science Foundation of China (No. 81000841 and 81272102). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.