Pico-Newton mechanical forces promote neurite growth

TL;DR

This study reveals that neurite growth in PC12 cells is continuously promoted by pico-Newton forces without a threshold, suggesting mechanical tension acts as an endogenous signal for neurite elongation.

Contribution

It challenges the previous threshold model by showing neurite elongation occurs at very low forces below 1 pN, indicating a different mechanism of mechanical signaling.

Findings

Neurite elongation occurs at forces below 1 pN.

No threshold force is required for neurite growth.

Mechanical tension acts as an endogenous signaling mechanism.

Abstract

Investigations over half a century have indicated that mechanical forces induce neurite growth - with neurites elongating at a rate of 0.1-0.3{\mu}mh^{-1} per pico-Newton (pN) of applied force - when mechanical tension exceeds a threshold, with this being identified as 400-1000 pN for neurites of PC12 cells. Here we demonstrate that there is no threshold for neurite elongation of PC12 cells in response to applied mechanical forces. Instead, this proceeds at the same previously identified rate, on the application of tensions with intensity below 1pN. This supports the idea of mechanical tension as an endogenous signal used by neurons for promoting neurite elongation.