Abstract
Distal arthrogryposis (DA) is a collection of rare developmental disorders characterized by congenital joint contractures. Most arthrogryposis mutations are in muscle- and joint-related genes, and the anatomical defects originate cell-autonomously within the musculoskeletal tissues. However, gain-of-function (GOF) mutations in PIEZO2, a principal mechanosensor in somatosensation, cause DA subtype 5 via unknown mechanisms. We show that expression of a GOF PIEZO2 mutation in proprioceptive sensory neurons mainly innervating muscle spindles and tendons is sufficient to induce DA5-like phenotypes in mice. Overactive PIEZO2 causes anatomical defects via increased activity within the peripheral nervous system during postnatal development. Surprisingly, overactive PIEZO2 is likely to cause joint abnormalities via increased exocytosis from sensory neuron endings without involving motor circuitry. This reveals a role for somatosensory neurons: excessive mechanosensation within these neurons disrupts musculoskeletal development. We also present proof-of-concept that Botox injection or dietary treatment can counteract the effect of overactive PIEZO2 function to evade DA-like phenotypes in mice when applied during a developmental critical period. These approaches might have clinical applications. Beyond this, our findings call attention to the importance of considering sensory mechanotransduction when diagnosing and treating other musculoskeletal disorders.
Acknowledgements: Our work is supported by National Institutes of Health grant (R35 NS105067, R01 DE022358, R25 SC3GM127195, R25 GM07138, R01GM133845, intramural) and Howard Hughes Medical Institute.
