Affiliations: [a] Micro-Nano Biomechanics Laboratory, Department of Mechanical Systems Engineering, Ibaraki University, Nakanarusawa-cho, Hitachi, Ibaraki, 316-8511, Japan
Abstract: BACKGROUND:Directional cell migration due to mechanosensing for in vivo microenvironment, such as microgrooved surfaces, is an essential process in tissue growth and repair in both normal and pathological states. Cell migration responses on the microgrooved surfaces might be reflected by the cell type difference, which is deeply involved in cellular physiological functions. Although the responses are implicated in focal adhesions (FAs) of cells, limited information is available about cell migration behavior on the microgrooved surfaces whose dimensions are comparable with the size of FAs. OBJECTIVE:In the present study, we investigated the cell orientation and migration behavior of normal vascular smooth muscle cells (VSMCs) and cervical cancer HeLa cells on the microgrooved surface. METHOD:The cells were cultured on the PDMS substrate comprising shallow grooves with 2-µm width and approximately 150-nm depth, which indicates the same order of magnitude as that of the horizontal and vertical size of FAs, respectively. The cell migration and intracellular structures were analyzed by live cell imaging and confocal fluorescence microscopy. The intracellular tension was also assessed using atomic force microscopy (AFM). RESULTS:VSMCs presenting well-aligned actin stress fibers with mature FAs revealed marked cell elongation and directional migration on the grooves; however, HeLa cells with nonoriented F-actin with smaller FAs did not. The internal force of the actin fibers was significantly higher in VSMCs than that in HeLa cells, and the increase or decrease in the cytoskeletal forces improved or diminished the sensing ability for shallow grooves, respectively. The results strongly indicated that directional cell migration should be modulated by cell type-specific cytoskeletal arrangements and intracellular traction forces. The differences in cell type-specific orientation and migration responses can be emphasized on the microgrooves as large as the horizontal and vertical size of FAs. CONCLUSION:The microgoove structure in the size range of the FA protein complex is a powerful tool to clarify subtle differences in the intracellular force-dependent substrate mechanosensing.
