Contribution of actin filaments and microtubules to cell elongation and alignment depends on the grating depth of microgratings.

Kyunghee Lee,Ee Hyun Kim,Nguyen Anh Tuan,Evelyn K Yim,Seok Jae Lee,Chi-Yong Eom,Naeun Oh,Kyoung G Lee,Sungsu Park,Nam Ho Bae

doi:10.1186/s12951-016-0187-8

Abstract

BackgroundIt has been reported that both chemical and physical surface patterns influence cellular behaviors, such as cell alignment and elongation. However, it still remains unclear how actin filament and microtubules (MTs) differentially respond to these patterns.ResultsWe examined the effects of chemical and physical patterns on cell elongation and alignment by observing actin filament and MTs of retinal pigment epithelium-1(RPE-1) cells, which were cultured on either fibronectin (FN)-line pattern (line width and spacing: 1 μm) or FN-coated 1 μm gratings with two different depths (0.35 or 1 μm). On the surface with either FN-line pattern or micrograting structure, the cell aspect ratios were at least two times higher than those on the surface with no pattern. Cell elongation on the gratings depended on the depth of the gratings. Cell elongation and alignment on both FN-line pattern and 1 μm gratings with 0.35 μm depth were perturbed either by inhibition of actin polymerization or MT depletion, while cell elongation and alignment on 1 μm gratings with 1 μm depth were perturbed only by MT depletion.ConclusionsOur results suggest that the contribution of actin filaments and MTs to the elongation and alignment of epithelial cells on microgratings depends on the groove depth of these gratings.Electronic supplementary materialThe online version of this article (doi:10.1186/s12951-016-0187-8) contains supplementary material, which is available to authorized users.

Highlights

It has been reported that both chemical and physical surface patterns influence cellular behaviors, such as cell alignment and elongation
When cell alignment on the patterns was determined by measuring angle differences between the major axis of cells and the long axis of FN-line or each micrograting, it was usually less than 15° (Table 1) that are deemed to be aligned according to a previous report [9]
R values indicate that cells on FN-lines and 1 μm gratings (0.35 and 1 μm deep) were significantly more elongated than those on the flat surface of tissue culture polystyrene (TCPS) (Fig. 1b; Table 3)

Summary

Results

We examined the effects of chemical and physical patterns on cell elongation and alignment by observing actin filament and MTs of retinal pigment epithelium-1(RPE-1) cells, which were cultured on either fibronectin (FN)line pattern (line width and spacing: 1 μm) or FN-coated 1 μm gratings with two different depths (0.35 or 1 μm). On the surface with either FN-line pattern or micrograting structure, the cell aspect ratios were at least two times higher than those on the surface with no pattern. Cell elongation on the gratings depended on the depth of the gratings. Cell elongation and alignment on both FN-line pattern and 1 μm gratings with 0.35 μm depth were perturbed either by inhibition of actin polymerization or MT depletion, while cell elongation and alignment on 1 μm gratings with 1 μm depth were perturbed only by MT depletion

Conclusions

Background

Results and discussion