title: Inhibition by female sex hormones of collagen gel contraction mediated by retinal pigment epithelial cells.
abstract: OBJECTIVE
  Collagen contraction mediated by retinal pigment epithelial (RPE) cells contributes to the pathogenesis of proliferative vitreoretinopathy (PVR). We examined the effects of sex hormones on this process.
  
  
  METHODS
  Mouse RPE cells were cultured in a type I collagen gel and exposed to 17β-estradiol, progesterone, or dehydro-epiandrosterone. Collagen contraction induced by transforming growth factor-β2 (TGF-β2) was determined by measurement of gel diameter. Expression of α-smooth muscle actin (α-SMA), as well as phosphorylation of Smad2 and myosin light chain (MLC), was examined by immunoblot analysis. Matrix metalloproteinase (MMP) release was evaluated by gelatin zymography. Fibronectin and interleukin-6 secretion was measured with immunoassays.
  
  
  RESULTS
  The female sex hormones 17β-estradiol and progesterone inhibited TGF-β2-induced collagen contraction mediated by RPE cells, whereas the male sex hormone dehydro-epiandrosterone had no such effect. The TGF-β2-induced release of MMP-2 and MMP-9 from RPE cells was also inhibited by 17β-estradiol and progesterone, and the MMP inhibitor GM6001 attenuated TGF-β2-induced collagen contraction. Expression of the mesenchymal markers α-SMA and fibronectin, interleukin-6 release, and Smad2 and MLC phosphorylation induced by TGF-β2 were all inhibited by 17β-estradiol and progesterone. Immunohistochemical analysis also detected nuclear immunoreactivity for estrogen and progesterone receptors in proliferative fibrocellular membranes of PVR patients.
  
  
  CONCLUSIONS
  Female sex hormones inhibited TGF-β2-induced collagen contraction mediated by RPE cells. This action appeared to be mediated through inhibition both of MMP, α-SMA, and fibronectin expression as well as of Smad2 and MLC phosphorylation. Female sex hormones might thus prove effective for the treatment of PVR.
authors.affiliation: Department of Ophthalmology, Yamaguchi University Graduate School of Medicine, Ube City, Yamaguchi, Japan.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Kimura
authors.forename: Tomoko
authors.initials: T
authors.lastname: Orita
authors.forename: Youichiro
authors.initials: Y
authors.lastname: Fujitsu
authors.forename: Yang
authors.initials: Y
authors.lastname: Liu
authors.forename: Makiko
authors.initials: M
authors.lastname: Wakuta
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Morishige
authors.forename: Katsuyoshi
authors.initials: K
authors.lastname: Suzuki
authors.forename: Koh-Hei
authors.initials: KH
authors.lastname: Sonoda
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D015153:Blotting, Western; D002478:Cells, Cultured; D003094:Collagen / Q000187:drug effects* / Q000378:metabolism; D004195:Disease Models, Animal; D058750:Epithelial-Mesenchymal Transition / Q000187:drug effects; D005260:Female; D005782:Gels; D012739:Gonadal Steroid Hormones / Q000494:pharmacology*; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D051379:Mice; D008856:Microscopy, Fluorescence; D008875:Middle Aged; D055213:Retinal Pigment Epithelium / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D018630:Vitreoretinopathy, Proliferative / Q000378:metabolism* / Q000473:pathology
chemical_list: D005782:Gels; D012739:Gonadal Steroid Hormones; D003094:Collagen
keywords: ECM; TGF-β; collagen; retinal pigment epithelium