TGFbeta-Smad signalling in postoperative human lens epithelial cells

Br J Ophthalmol. 2002 Dec;86(12):1428-33. doi: 10.1136/bjo.86.12.1428.


Aims: To localise Smads3/4 proteins in lens epithelial cells (LECs) of fresh and postoperative human specimens. Smads3/4 are involved in signal transduction between transforming growth factor beta (TGFbeta) cell surface receptors and gene promoters. Nuclear localisation of Smads indicates achievement of endogenous TGFbeta signalling in cells.

Methods: Three circular sections of the anterior capsule, one lens, and 17 capsules undergoing postoperative healing were studied. Immunohistochemistry was performed for Smads3/4 in paraffin sections of the specimens. The effect of exogenous TGFbeta2 on Smad3 subcellular localisation was examined in explant cultures of extracted human anterior lens epithelium.

Results: The cytoplasm, but not the nuclei, of LECs of uninjured lenses was immunoreactive for Smads3/4. In contrast, nuclear immunoreactivity for Smads3/4 was detected in LECs during capsular healing. Nuclei positive for Smads3/4 were observed in monolayered LECs adjacent to the regenerated lens fibres of Sommerring's ring. Interestingly, the nuclei of LECs that were somewhat elongated, and appeared to be differentiating into fibre-like cells, were negative for Smads3/4. Fibroblast-like, spindle-shaped lens cells with nuclear immunoreactivity for nuclear Smads3/4 were occasionally observed in the extracellular matrix accumulated in capsular opacification. Exogenous TGFbeta induced nuclear translocation of Smad3 in LECs of anterior capsule specimens in explant culture.

Conclusions: This is consistent with TGFbeta induced Smad signalling being involved in regulating the behaviour of LECs during wound healing after cataract surgery.

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Cataract Extraction*
  • Cells, Cultured
  • DNA-Binding Proteins / analysis*
  • Epithelial Cells / chemistry
  • Female
  • Humans
  • Lens, Crystalline / chemistry*
  • Lens, Crystalline / cytology
  • Male
  • Middle Aged
  • Signal Transduction
  • Smad3 Protein
  • Smad4 Protein
  • Trans-Activators / analysis*
  • Wound Healing
  • beta-Crystallins / analysis


  • DNA-Binding Proteins
  • SMAD3 protein, human
  • SMAD4 protein, human
  • Smad3 Protein
  • Smad4 Protein
  • Trans-Activators
  • beta-Crystallins