MRC1 and osteoarthritis: In the DRG, MRC1 expression has been used to identify “M2-macrophages,” which resolve osteoarthritis- (Raoof et al., 2021) or chemotherapy-induced pain by producing IL-10 (Singh et al., 2022) or inflammatory pain by transferring mitochondria to sensory neurons (van der Vlist et al., 2022).