Nanobiomechanics and Mechanotransduction of Sensory Neurons

A detailed knowledge of mechanical parameters such as cell elasticity, stiffness and viscoelasticity is essential for understanding the mechanisms that control the mechanotransduction in mechanosensory neurons (MSN). Indeed, in order to tune and maximize their sensitivity, MSN should be neither too rigid nor to compliant; moreover they are expected to show different elasticity as a function of the typology of mechanical stimulus they should record. However a precise correlation between MSN mechanical properties and mechanotransduction mechanism is still missing, and the sensory mechanical transduction, necessary for the senses of touch and pain, remains poorly understood. Indentation measurements by atomic force microscopy (AFM) enable to investigate and quantify in vitro the softness of living MSN thanks to its ability to measure low forces (pN) and nanometer scale displacement. Moreover, the integration of AFM with fluorescence microscopy opens up the possibility to relate the involvement or activation of either cytoplasmatic structures or transmembrane proteins with variations of cell mechanical properties and, as result, their role in the modulation of mechanosensory neurons activity. In this study we performed AFM indentation measurements to evaluate the mechanical properties of wild type and genetically modified proteins of the stomatin system of dorsal root ganglia (DRG). We found a decrease of cell elasticity in DRG neurons where stomatin system is genetically modified. The role of cell elasticity in mechanotransduction regulation of mechanosensory neurons is discussed.