Lens fibre differentiation is a life-long process related with lens transparency,\nand is particularly intense during development, being related with an FGF-2\nantero-posterior gradient at the equator level as the main growth factor involved\nwhich has been related with the basal membrane of the lens anlagen\nknown as ââ?¬Å?Lens capsule ââ?¬Â. However the lens fibre differentiation induced by\nFGF2 depends, as in other biological systems, on the local bioavailability of\nFGF-2 regulated by their relationship with extracellular matrix molecules as\nHeparan Sulphate Proteoglycans. Here, we try to clarify how Perlecan (a\nheparan sulphate proteoglycan specific from basement membranes) is involved\nin lens fibre differentiation at earliest stages of eye development. Our results\nshow that Perlecan, is a major component in the lens capsule during the earliest\nstages of lens development in chick embryos being present during lens\nplate induction, lens vesicle stage and the onset of lens fibre differentiation. In\norder to demonstrate a direct involvement of HSPG-Perlecan in lens fibre differentiation,\nwe generate depleted lenses by HSPG-Perlecan synthesis disruption\nand specific enzymatic digestion. The HSPG-Perlecan depleted lens show a significant\ndelay or abolition in the lens fibre differentiation which remains in an\nimmature cells displaying DNA synthesis in the posterior epithelium and a decrease\nin FGF2 lens expression. These data support the hypothesis that lens\ncapsule HSPG-Perlecan is a key molecule involved in lens fibre differentiation\nduring development, probably by involvement in FGF-2 biodisponibility.
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