Laminin-1 increases motility, path-searching, and process dynamism of rat and mouse Muller glial cells in vitro: implication of relationship between cell behavior and formation of retinal morphology.

Spatial correlation was observed between the localization of laminin-1 at the inner limiting membrane (ILM) and extensive Muller glial process arborization in the same area, as demonstrated by immunolabeling of Muller glial processes and laminin-1 in rat retinae in situ. To test if this spatial correlation is due to a functional relationship, we investigated the impact of laminin-1 on the motility of cultured primary rat and mouse retinal Muller glial cells by statistical analysis of computer-controlled videomicroscopic time-lapse images. We demonstrate that laminin-1 increases motility and path-searching activity of Muller cells in vitro and it also enhances the cells' process formation/withdrawal dynamism. The increase in path-searching activity and cell process dynamism indicates that there is a functional relationship between laminin-1 and Muller glial cells presumably involving signaling towards the cytoskeleton. We hypothesize that laminin-1 is involved in process arborization of Muller cells at the vitread border of the retina resulting in the formation of the functional barrier made up of Muller glial endfeet.