Small extracellular vesicles from pain-insensitive individuals modulate sensory-like neurons’ responses in vitro

Extracellular vesicles are emerging regulators of intercellular signalling in the nervous system, including mechanisms controlling sensory neuron excitability and pain processing. Marsili syndrome, a rare condition characterized by congenital pain insensitivity, provides a unique human model for investigating these pathways. Here, we show that urinary small extracellular vesicles (sEVs) derived from Marsili subjects reduce the responsiveness in differentiated sensory-like F-11 neurons. Marsili sEVs exhibited reduced size, comparable particle concentration, and a distinct microRNA cargo characterized by increased levels of miR-135a-5p and miR-138-5p and reduced miR-183 expression. Functionally, Marsili sEVs attenuated membrane depolarization and intracellular Ca²⁺ influx following inflammatory stimulation and KCl activation, indicating reduced responsiveness in differentiated F-11 cells. These effects were associated with marked downregulation of the potassium channel modulatory subunit KCNV1. Overall, our findings suggest that urinary sEVs from individuals with Marsili syndrome may contribute to the regulation of sensory neuron-like responsiveness by transferring bioactive molecular cargo. These findings identify urinary sEVs as candidate modulators of neuronal signalling that warrant further investigation in primary neurons and in vivo models.