Abstract
Purpose :
Corneal endothelial cells exhibit vastly different apical and basolateral surface geometries, resulting from a unique multipolar shape and complex lateral membrane ruffles (Forrest et al., in press; Harrison et al., in press). To gain clues about cellular morphogenesis and the physiological significance of this unique architecture, we examined the timing of cell shape changes during tissue development.
Methods :
Corneas from both wild type (WT/C57BL6) mice and a compound transgenic strain (P0-Cre; R26-Tomato) were obtained at postnatal day 6 (P6), P8, P10, P14, P16 and P18. WT and P0-Cre−; R26-Tomato+ transgenic tissues were double-labeled with antibodies to ZO-1 and NCAM to view apical and lateral borders, respectively. P0-Cre+; R26-Tomato+ tissues were examined directly to image cells filled with red fluorescent protein (RFP). Corneas were then fixed, flat-mounted and visualized by conventional fluorescence and confocal microscopy.
Results :
Polygonal apical borders characterized endothelial cells at all time points. On the other hand, a transition from smooth to ruffled lateral boundaries was seen between P12 and P14, with membrane complexity increasing up to P18. By P14, cells expressing cytoplasmic RFP were also observed to extend multiple processes that radiated outward in the plane of the monolayer.
Conclusions :
Our results indicate that endothelial cell geometry undergoes a fundamental change around the time of eyelid opening. In this regard, the data suggest that attainment of complex cell shape, and the consequent increase in basolateral membrane, may be important for mature endothelial function.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.