Directional change produced by perpendicularly‐oriented microgrooves is microtubule‐dependent for fibroblasts and epithelium

Abstract

Anisotropic substrata such as micromachined grooves can control cell shape, orientation, and the direction of cell movement, a phenomena termed topographic guidance. Although many types of cells exhibit topographic guidance, little is known regarding cell responses to conflicting topographic cues. We employed a substratum with intersecting grooves in order to present fibroblasts and epithelial cells with conflicting topographic cues. Using time-lapse and confocal microscopy, we examined cell behavior at groove intersections. Migrating fibroblasts and epithelial cells typically extended a cell process into the intersection ahead of the cell body. After travelling along the "X" groove to enter the intersection, the leading lamellipodia of the cell body encountered the perpendicular "Y" groove, and spread latterly along the "Y" groove. The formation of lateral lamellipodia resulted in cells forming "T" or "L" morphologies, which were characterized by the formation of phosphotyrosine-rich focal adhesions at the leading edges. The "Y" groove did not prove an absolute barrier to cell migration, particularly for epithelial cells. Analysis of cytoskeletal distribution revealed that F-actin bundles did not adapt closely to the groove patterns, but typically did align to either the "X" or "Y" grooves. In contrast microtubules (MT) adapted closely to the walls. Inhibition of microtubule nucleation attenuated fibroblast and epithelial cell orientation within the intersection of the perpendicular grooves. We conclude that MT may be the prime determinant of fibroblast and epithelial cell conformation to conflicting topographies.

Surface micro- and nano-texturing of stainless steel by femtosecond laser for the control of cell migration

“…The experimental results here presented are partially related to those obtained by D. Brunette et al 37,. which was the first group that reported a directional change in the cell behavior produced by the fabrication of microstructures with different orientation fabricated by photolithography techniques.…”

Topography, Cell Response, and Nerve Regeneration

“…Both hypotheses are supported by studies using topographies with subcellular geometries which indicate that actin stress fibers and microtubules align in the feature direction (48, 95, 143, 145–148). Microgrooves have also been reported to reduce the complexity of the neuronal arbor, with a stronger effect on smaller channels, which may be due to restriction of the growing cytoskeleton (43).…”

“…It has been hypothesized that alignment to anisotropic cues such as grooved surfaces occurs as (1) cells minimize the distortion to their cytoskeletons which would occur if cells ignored rather than followed guidance cues (143), and (2) that these cues create a pattern of mechanical stress, directly causing the cells to align with the grooves (144). Both hypotheses are supported by studies using topographies with subcellular geometries which indicate that actin stress fibers and microtubules align in the feature direction (48, 95, 143, 145–148).…”

Engineering of Micro‐ and Nanostructured Surfaces with Anisotropic Geometries and Properties

“…microtubules, actin fi laments) and that the cell takes the energetically favorable shape that minimizes the stress within its cytoskeleton. [ 323 ] In support of this theory, cell types with a less well-organized cytoskeletal structure are less affected by contact guidance. [ 324 ] In particular, Dalby et al have proposed that fi lopodia are responsible for chemically and physically probing the cell's environment.…”