Superficial groove structure in the size of focal adhesion can clarify cell-type-specific differences in force-dependent substrate mechanosensing

Abstract

Mechanosensing-based cell orientation and migration in microenvironments, such as microgrooved surfaces, are essential in biological tissue growth and repair. These responses might be cell type-dependent as they are deeply involved in cellular functions. Despite their orientation and migration responses are depended on cell-substrate adhesion, which is deeply involved with focal adhesions (FAs) of cells, we have limited information on the cell behavior on FA-sized microgrooved surfaces. Here, we systematically investigated the cell orientation and migration behavior of primary porcine aortic smooth muscle cells (PASMs), embryonic rat aortic smooth muscle cells with fibroblast-like phenotype (A7r5), and human cervical cancer cells (HeLa) on a substrate comprised of superficial grooves with three widths (1 μm, 5 μm, and 10 μm) and 150-nm depth, which are the same order of magnitude of the three-dimensional size of FAs. PASM and A7r5 cells including thick bundles of actin fibers with elongated FAs showed pronounced cell polarization and directional migration on the 1 and 5 μm wide grooves. PASMs were more sensitive to the superficial grooves than A7r5 cells. HeLa cells adhering to the grooves had non-oriented actin fibers with smaller FAs, and they did not show specific orientation nor directional migration in any groove type. Atomic force microscopy elucidated that the mechanical tension of the actin fibers in live cells had a significant positive correlation with the length/width ratio of FAs, reflecting the cell alignment and directional migration on the grooves. The increase or decrease in the mechanical tension of the actin fibers improved or diminished the mechanosensing for the grooves, respectively. The results strongly suggested that the differences in cell type-specific alignment and migration become much more pronounced on the microgrooves which are similar in three-dimensional size of FA, and that is useful for clarifying slight differences in force-dependent cellular mechanosensing.