Abstract
Purpose: :
Integrins are a large family of heterodimeric transmembrane receptors consisting of one alpha and one beta subunit that regulate cell–ECM and cell–cell interactions. Integrins are important for lens development and function however the full diversity of the integrins expressed in the lens has not been explored.
Methods: :
RT–PCR and western blot analysis were performed to characterize integrin expression at the RNA and protein levels in embryonic and adult mouse lens as well as adult mouse lenses microdissected into epithetlial (with capsule), superficial and deep fiber cell fractions. Cellular localization of integrin subunits has been demonstrated by confocal immunofluorescence using frozen sections.
Results: :
RT–PCR and immunofluorescence showed expression of α1, α2, α3, α5, α6, α9, α10, α11, αV, ß1, ß3, ß5 and ß8 integrins in the embryonic and adult lens. In adult lens α11 integrin expression was predominantly associated with epithelium, whereas expression of the α2, α6, α10, αV, ß1 and ß8 subunits was restricted mainly to superficial fibers. α1, α3 and α5 integrins were expressed in both epithelium and fibers at the same level. Expression of α9 and ß3 integrins was very low in all lens cells. In embryonic lens high expression of α2, α3, α6 and ß8 integrins was detected from 12.5 dpc up to birth. All integrins were localized mainly in lens fiber cells, especially in transition zone.
Conclusions: :
This study provides the first demonstration of α9, α10, α11, ß5 and ß8 integrin expression in the mouse lens. Both lens epithelial and lens fiber cells express a specific subset of integrin subunits which are likely to be important to the maintenance of their differentiated phenotype.
Keywords: crystalline lens • cell adhesions/cell junctions • differentiation