Cellular and molecular biomechanics

Abstract

Cells exist in a mechanical environment and must be able to elicit an appropriate response to strains evoked by fluid flow, compression, pressure and stretch. The ability to detect a range of forces (from 10−4 through to 104 N m−2, reflecting a faint sound and aortic pressure, respectively) is vital in order to elicit the appropriate cascade of molecular events that facilitate the physiological processing of sensory information. The detection of mechanical strain is mediated by mechano-sensitive components of cells and is a property of a wide range of tissue types. Mechanosensors in the cells of the skin and ear are critical for processing information about touch and hearing, while other mechanosensors respond to blood pressure (baroreceptors), muscle stretch (spindle receptors) and limb positions (proprioceptors). Bone tissue detects mechanical stress, and this informs the bone remodeling process, while endothelial cells lining blood vessels respond to shear stress evoked by fluid flow to initiate vascular remodeling. The ability to respond to mechanical stimuli also regulates fundamental cellular events such as proliferation, cell spreading, differentiation, motility and the maintenance of cell shape. The precise cellular mechanisms underlying mechanosensation remain to be fully resolved, but in recent years a number of surface proteins have been identified that serve a role as mechanoreceptors. Biological systems have evolved a complex array of mechanoreceptors to transduce force into an electrical and/or intracellular biochemical cascade. Such signaling pathways are intricately linked with cellular responsiveness and adaptation to mechanical stimulation.