Fig. 5: Cell–cell junctions of cardiac LECs undergo transformation during postnatal development.
From: Cardiac lymphatics retain LYVE-1-dependent macrophages during neonatal mouse heart regeneration
High-magnification confocal imaging of LECs within vessels stained for VE-cadherin and LYVE-1 enabled visualization of cell–cell junctions at different postnatal stages (a–i). The morphology of the junctions at P1 appeared to be continuous, resembling that of zippers (arrows in c). Zippered junctions were also observed at P7 (arrows in f), but there was also the emergence of discontinuous buttoned junctions (arrowheads in f) as well as those that were intermediate between zipper and button, indicative of a more cell-permeable endothelium. The more complete transformation to buttoned junctions was further evident by P14 (arrowheads in i), although some intermediate and zippered junctions were still evident at this stage (arrows in i). Quantification of the percent incidence of the three junction types (zippered, intermediate and buttoned) across the P1–P7–P14 timecourse (j) reveals the trend in transition from zippered (impermeable) to buttoned (permeable) during postnatal development. Macrophage morphology also transformed during this 2-week period. n = 5 for P1 and P14, n = 2 for P7; lymphatic vessel tips within the visual field were analyzed, 2–4 per heart. Significant differences were calculated using unpaired Student’s t-tests. Mean percent was plotted. Scale bars, 20 μm.
