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Mann JM, Lam RHW, Weng S, Sun Y, Fu J. A silicone-based stretchable micropost array membrane for monitoring live-cell subcellular cytoskeletal response. LAB ON A CHIP 2012; 12:731-40. [PMID: 22193351 PMCID: PMC4120061 DOI: 10.1039/c2lc20896b] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
External forces are increasingly recognized as major regulators of cellular structure and function, yet the underlying mechanism by which cells sense forces and transduce them into intracellular biochemical signals and behavioral responses ('mechanotransduction') is largely undetermined. To aid in the mechanistic study of mechanotransduction, herein we devised a cell stretching device that allowed for quantitative control and real-time measurement of mechanical stimuli and cellular biomechanical responses. Our strategy involved a microfabricated array of silicone elastomeric microposts integrated onto a stretchable elastomeric membrane. Using a computer-controlled vacuum, this micropost array membrane (mPAM) was activated to apply equibiaxial cell stretching forces to adherent cells attached to the microposts. Using the mPAM, we studied the live-cell subcellular dynamic responses of contractile forces in vascular smooth muscle cells (VSMCs) to a sustained static equibiaxial cell stretch. Our data showed that in response to a sustained cell stretch, VSMCs regulated their cytoskeletal (CSK) contractility in a biphasic manner: they first acutely enhanced their contraction to resist rapid cell deformation ('stiffening') before they allowed slow adaptive inelastic CSK reorganization to release their contractility ('softening'). The contractile response across entire single VSMCs was spatially inhomogeneous and force-dependent. Our mPAM device and live-cell subcellular contractile measurements will help elucidate the mechanotransductive system in VSMCs and thus contribute to our understanding of pressure-induced vascular disease processes.
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Affiliation(s)
- Jennifer M. Mann
- Integrated Biosystems and Biomechanics Laboratory, University of Michigan, Ann Arbor, MI, 48105, USA
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI, 48105, USA
| | - Raymond H. W. Lam
- Integrated Biosystems and Biomechanics Laboratory, University of Michigan, Ann Arbor, MI, 48105, USA
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI, 48105, USA
| | - Shinuo Weng
- Integrated Biosystems and Biomechanics Laboratory, University of Michigan, Ann Arbor, MI, 48105, USA
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI, 48105, USA
| | - Yubing Sun
- Integrated Biosystems and Biomechanics Laboratory, University of Michigan, Ann Arbor, MI, 48105, USA
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI, 48105, USA
| | - Jianping Fu
- Integrated Biosystems and Biomechanics Laboratory, University of Michigan, Ann Arbor, MI, 48105, USA
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI, 48105, USA
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, 48105, USA
- Correspondence should be addressed to J. Fu [J. Fu (, Tel: 01-734-615-7363, Fax: 01-734-647-7303)]
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Abstract
Increased blood pressure (essential hypertension) is associated with increased cardiovascular risk, and the condition is treated primarily with a view to reducing this parameter. However, in the early stages, the main pathological changes are increased peripheral resistance and altered cardiovascular structure. The aim of this MiniReview was to trace the endeavours over the past several decades to translate these findings into answering the question whether normalization of resistance vessel structure should be a target for therapy. This MiniReview describes first the altered structure of the resistance vasculature in essential hypertension, where the vessels show increased media/lumen ratio because of inward eutrophic remodelling. Secondly, evidence is presented that altered small artery structure appears to have prognostic consequences. Then, the cellular mechanisms that may be involved are discussed, where there is evidence that vasoconstriction in itself can cause inward remodelling and that this can be prevented by vasodilators. This leads to a discussion of the degree to which it may be possible to rectify the abnormal structure, where it appears that this may be achieved using a therapy that causes vasodilatation in the patient concerned. Finally, the consequences of these findings are considered as regards clues for strategies that may be able to improve the outcome of antihypertensive therapy. The MiniReview concludes that there is reasonably strong evidence that improvement in abnormal resistance vessel structure requires a treatment that reduces peripheral resistance in the individual patient.
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Folkow B. Cardiovascular “Remodeling” in Rat and Human: Time Axis, Extent, and In Vivo Relevance. Physiology (Bethesda) 2010; 25:264-5; author reply 266-7. [DOI: 10.1152/physiol.00015.2010] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
- Björn Folkow
- Department of Physiology, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Göteborg, Sweden
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