An Introductory Review of Cell Mechanobiology

Abstract

Mechanical loads induce changes in the structure, composition, and function of living tissues. Cells in tissues are responsible for these changes, which cause physiological or pathological alterations in the extracellular matrix (ECM). This article provides an introductory review of the mechanobiology of load-sensitive cells in vivo, which include fibroblasts, chondrocytes, osteoblasts, endothelial cells, and smooth muscle cells. Many studies have shown that mechanical loads affect diverse cellular functions, such as cell proliferation, ECM gene and protein expression, and the production of soluble factors. Major cellular components involved in the mechanotransduction mechanisms include the cytoskeleton, integrins, G proteins, receptor tyrosine kinases, mitogen-activated protein kinases, and stretch-activated ion channels. Future research in the area of cell mechanobiology will require novel experimental and theoretical methodologies to determine the type and magnitude of the forces experienced at the cellular and sub-cellular levels and to identify the force sensors/receptors that initiate the cascade of cellular and molecular events.

Mechanoregulation of gene expression in fibroblasts

“…Micropipette aspiration and optical trapping exert mechanical loading on a whole cell and are useful for determining the mechanical properties of the entire cell (Hochmuth, 2000;Takahashi et al, 2003). To study the mechanobiological response of a population of fibroblasts, however, mechanical loadings have been applied mainly by various substrate stretching methods (Almekinders et al, 1993;Banes et al, 1999;Wang and Thampatty, 2006).…”

“…1). For uniaxial stretching, a rectangular substrate is lengthened in its stretching direction but shortened in its orthogonal direction (Wang and Thampatty, 2006). Such a uniaxial cell stretching system using compliant microgrooved silicone dishes, in which cells align mimicking in vivo cell alignment and orientation, has been successfully used in studies concerning mechanical loading effects on tendon fibroblasts (Yang et al, ,2005.…”

“…Besides integrins, other various potential biochemical mediators of mechanotransduction such as mechanosensitive cell surface receptors including receptor tyrosine kinases (RTKs) and heterotrimeric guanine nucleotide-binding proteins (G proteins) also have been suggested in fibroblasts (Ruwhof and van der Laarse, 2000;Wang, 2006b;Wang and Thampatty, 2006). Non-integrin cell surface receptors such as CD44 and syndecan, which serve as receptors for cell adhesion molecules, growth factors, and cytokines, are also suggested as candidates for mechanotransduction (Boraldi et al, 2003;Yoneda and Couchman, 2003;Gigant-Huselstein et al, 2004).…”

A thermodynamically motivated model for stress-fiber reorganization

“…In turn, the cell's cytoskeleton influences a broad range of cellular activities. For example, cytoskeletal arrangements in arterial endothelial cells affect intracellular signaling and gene expression which regulate cellular functions such as apoptosis, proliferation and morphology (Wang and Thampatty 2006).…”

Effect of micro-vibration culture system on embryo development

“…The combination of these in vivo mechanical forces leads to an average ovum velocity of 0.1 μm/s and a maximum velocity of up to 8.6 μm/s [12][13][14][15]. These in vivo mechanical forces are believed to induce cell-to-cell communication, exert beneficial effects by refreshing the fluid surrounding the embryo and eliminate metabolites emitted from embryos [16][17][18][19]. Studies to achieve higher quality embryos by external stimuli using machines (i.e., tilting machines and micro-vibrators) to replicate in vivo mechanical forces have been recently reported [20,21].…”