Schwann cell endosome CGRP signals elicit periorbital mechanical allodynia in mice

F De Logu, R Nassini, A Hegron, L Landini… - Nature …, 2022 - nature.com
F De Logu, R Nassini, A Hegron, L Landini, DD Jensen, R Latorre, J Ding, M Marini…
Nature communications, 2022nature.com
Efficacy of monoclonal antibodies against calcitonin gene-related peptide (CGRP) or its
receptor (calcitonin receptor-like receptor/receptor activity modifying protein-1, CLR/RAMP1)
implicates peripherally-released CGRP in migraine pain. However, the site and mechanism
of CGRP-evoked peripheral pain remain unclear. By cell-selective RAMP1 gene deletion,
we reveal that CGRP released from mouse cutaneous trigeminal fibers targets CLR/RAMP1
on surrounding Schwann cells to evoke periorbital mechanical allodynia. CLR/RAMP1 …
Abstract
Efficacy of monoclonal antibodies against calcitonin gene-related peptide (CGRP) or its receptor (calcitonin receptor-like receptor/receptor activity modifying protein-1, CLR/RAMP1) implicates peripherally-released CGRP in migraine pain. However, the site and mechanism of CGRP-evoked peripheral pain remain unclear. By cell-selective RAMP1 gene deletion, we reveal that CGRP released from mouse cutaneous trigeminal fibers targets CLR/RAMP1 on surrounding Schwann cells to evoke periorbital mechanical allodynia. CLR/RAMP1 activation in human and mouse Schwann cells generates long-lasting signals from endosomes that evoke cAMP-dependent formation of NO. NO, by gating Schwann cell transient receptor potential ankyrin 1 (TRPA1), releases ROS, which in a feed-forward manner sustain allodynia via nociceptor TRPA1. When encapsulated into nanoparticles that release cargo in acidified endosomes, a CLR/RAMP1 antagonist provides superior inhibition of CGRP signaling and allodynia in mice. Our data suggest that the CGRP-mediated neuronal/Schwann cell pathway mediates allodynia associated with neurogenic inflammation, contributing to the algesic action of CGRP in mice.
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