Hasegawa et al. reveal how synovial joints detect systemic inflammation through specialized fenestrated blood vessels at the synovial periphery. Three distinct macrophage populations and nociceptor neurons form a sentinel unit around these vessels, coordinating immune responses and pain signalling through interleukin-1β (IL-1β) and calcitonin gene-related peptide (CGRP) signalling.
- Oumaima Ben Brahim
- Stefan Uderhardt
