HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 295/6/C1569    most recent 00098.2008v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Nagayama, K. Articles by Matsumoto, T. Search for Related Content PubMed PubMed Citation Articles by Nagayama, K. Articles by Matsumoto, T.

MUSCLE CELL BIOLOGY AND CELL MOTILITY

Contribution of actin filaments and microtubules to quasi-in situ tensile properties and internal force balance of cultured smooth muscle cells on a substrate

Biomechanics Laboratory, Department of Mechanical Engineering, Nagoya Institute of Technology, Nagoya, Japan

Submitted 18 February 2008 ; accepted in final form 7 October 2008

The effects of actin filaments (AFs) and microtubules (MTs) on quasi-in situ tensile properties and intracellular force balance were studied in cultured rat aortic smooth muscle cells (SMCs). A SMC cultured on substrates was held using a pair of micropipettes, gradually detached from the substrate while maintaining in situ cell shape and cytoskeletal integrity, and then stretched up to 15% and unloaded three times at the rate of 1 µm every 5 s. Cell stiffness was 20 nN per percent strain in the untreated case and decreased by 65% and 30% following AF and MT disruption, respectively. MT augmentation did not affect cell stiffness significantly. The roles of AFs and MTs in resisting cell stretching and shortening were assessed using the area retraction of the cell upon noninvasive detachment from thermoresponsive gelatin-coated dishes. The retraction was 40% in untreated cells, while in AF-disrupted cells it was <20%. The retraction increased by 50% and decreased by 30% following MT disruption and augmentation, respectively, suggesting that MTs resist intercellular tension generated by AFs. Three-dimensional measurements of cell morphology using confocal microscopy revealed that the cell volume remained unchanged following drug treatment. A concomitant increase in cell height and decrease in cell area was observed following AF disruption and MT augmentation. In contrast, MT disruption significantly reduced the cell height. These results indicate that both AFs and MTs play crucial roles in maintaining whole cell mechanical properties of SMCs, and that while AFs act as an internal tension generator, MTs act as a tension reducer, and these contribute to intracellular force balance three dimensionally.

cellular biomechanics; mechanical properties; hysteresis; cell retraction; cellular prestress