Purchase this article with an account.
VALENTINA IORIO, Lee David Troughton, Kevin John Hamill; LaNt α31: a new regulator of corneal epithelial cell behaviour?. Invest. Ophthalmol. Vis. Sci. 2015;56(7 ):2068.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
LaNt α31 (laminin N-terminal α31), a product of alternative splicing from the laminin α3 encoding gene, has been shown to have a functional role in epithelial basement membranes of skin. Its presence and function within the anterior segment has not been studied. Our aim was to determine LaNt α31 distribution in human corneal, limbal and conjunctival epithelia and to analyse its functional roles in corneal epithelial cells.
LaNt α31 distribution in human anterior segment sections was determined by immunohistochemistry using a novel monoclonal antibody raised against a LaNt α31 specific peptide sequence. In vitro functional assays were performed using a limbal-derived corneal epithelial cell line (hTCEpi).<br /> LaNt α31 function in corneal epithelial cells was studied by comparing attachment, motility and scratch wound closure rates of hTCEpi cells where exposed to increased extracellular LaNt α31 either through exogenous addition of purified protein or via adenoviral induced overexpression. Confocal microscopy was used to determine LaNt α31 GFP and laminin β3 mCherry localisation and deposition in live cells.
LaNt α31 localises in the intracellular compartment of the corneal epithelium, decorates the basement membrane in the limbus but is absent from the conjunctiva (Fig.1). hTCEpi attachment to laminin 111 was significantly reduced in the presence of exogenous LaNt α31 (30% reduction, p<0.05) and in cells overexpressing LaNt α31 (40% reduction, p<0.05). No differences were observed on control coatings of collagen I, IV or fibronectin. LaNt α31 overexpressing cells also exhibited diminished scratch closure rates and cell migration speeds (0.9 μm/min versus 1.4 μm/min in controls). Live molecular imaging revealed that GFP tagged LaNt α31 clustered at the periphery of cells, where it co-distributed with laminin β3. Moreover, as cells moved across a preformed matrix, clusters of LaNt α31 rapidly formed and dissociated intracellularly along the matrix-apposed surface of cells, at sites of laminin deposits.
The differential distribution of LaNt α31 and in vitro functional data suggests a context specific role for this protein, likely in modulating cell-matrix interaction. This implicates the LaNts as new players in regulating corneal epithelial cell behaviour, with potential roles in stem cell maintenance, corneal homeostasis and wound repair.
This PDF is available to Subscribers Only