RESPONSE OF SINGLE, PAIRS, AND CLUSTERS OF EPITHELIAL-CELLS TO SUBSTRATUM TOPOGRAPHY

Cells cultured on grooved substrata change their shape, orientation, a nd direction of locomotion in response to substratum topography, a phe nomenon called contact or topographic guidance. Porcine epithelial cel ls (E-cells) spread on micromachined grooved or smooth control surface s were examined by epifluorescence and confocal microscopy to determin e area, cell shape, and orientation in conjunction with distributions and orientations of actin filaments and microtubules. Single cells, ce lls within a pair or cluster, and pairs or clusters considered as a un it were compared. As expected, cell contact increased cell spreading, but surprisingly, increased cell contact influenced cell shape on smoo th and grooved surfaces and increased alignment of cells spread on gro oves. Both actin filaments and microtubules aligned initially and most consistently along the walls and ridge-groove edges. Single E-cells d isplayed the least variability of aligned cytoskeletal patterns. E-cel ls within clusters displayed the most variability as local topographic effects on the cytoskeleton could be overridden by adjacent cell cont act. Overall, contact guidance of E-cells was neither synonymous with nor contingent upon an elliptical morphology oriented to the topograph y. E-cells also differed from fibroblasts in their response to cell co ntact and in their lack of a relationship between cell polarity and lo comotion.