Touch-induced mechanical strain in somatosensory neurons is independent of extracellular matrix mutations inCaenorhabditis elegans

Abstract

Cutaneous mechanosensory neurons are activated by mechanical loads applied to the skin, and these stimuli are proposed to generate mechanical strain within sensory neurons. Using a microfluidic device to deliver controlled stimuli to intact animals and large, immobile, and fluorescent protein-tagged mitochondria as fiducial markers in the touch receptor neurons (TRNs), we visualized and measured touch-induced mechanical strain in C. elegans worms. At steady-state, touch stimuli sufficient to activate TRNs induce an average strain of 3.1% at the center of the actuator and this strain decays to near zero at the edges of the actuator. We also measured strain in animals carrying mutations affecting links between the extracellular matrix (ECM) and the TRNs but could not detect any differences in touch-induced mechanical strain between wild-type and mutant animals. Collectively, these results demonstrate that touching the skin induces local mechanical strain in intact animals and suggest that a fully intact ECM is not essential for transmitting mechanical strain from the skin to cutaneous mechanosensory neurons.

A rigidity phase transition of Stomatin condensates governs a switch from transport to mechanotransduction

“…Upon sudden pressure release, the FRET index increased again to the same value as before the indentation, indicating that the MEC-2 can reversibly transmit force between the PHB and the C-terminal domain. Consistent with previous reports, tension was highest in regions directly below the actuator and did not propagate into the distal regions of the axon ( 54 ). In the C-terminal TSMod fusion intended to serve as a pressure-insensitive control (fig.…”

An asymmetric mechanical code ciphers curvature-dependent proprioceptor activity

“…The procedure of animal insertion into the trapping channel has been described in detail elsewhere ( 69 ). Briefly, to load individual in the chip, one young adult worm transgenic for TSMod in UNC-70 and its derivatives (GN517, GN519, GN600, and MSB233) ( 20 ) were picked from an NGM plate containing OP50 bacteria and transferred to a 5-μl droplet of 30% OptiPrep [to reduce scattering from PDMS due to refractive index mismatches between the animal and the surrounding ( 70 , 71 )] placed onto a hydrophobic substrate (25 cm 2 of Parafilm) to swim for 30 s and rid themselves from bacteria. Then, using a stereo dissecting scope at ×60 total magnification (Leica S80), the animals were aspirated into a 23-gauge metal tube (Phymep) connected to a 5-ml syringe (VWR) with a polyethylene (PE) tube (Phymep, BTPE-50; 0.58 mm by 0.97 mm) prefilled with 30% OptiPrep buffer.…”

Mechanical Stretch Inhibition Sensitizes Proprioceptors to Compressive Stresses

“…In brief, to load individual in the chip, one young adult worm transgenic for TSMod in UNC-70 and its derivatives (GN517, GN519, GN600, MSB233; Ref. [19]) were picked from an NGM plate containing OP50 bacteria and transferred to a 5 µl droplet of 30% Optiprep (to reduce scattering from PDMS due to refractive index mismatches between the animal and the surrounding [65,66])…”