Table 1.

Macrophage-derived exosomes in bone metabolism.

Cell of origin	Types	Mediators	Main biological effects	References
Bone marrow macrophage	Exosomes	Undetected	Promote osteogenesis	Wei et al., 2019
	MicroRNAs	mir-21	Promote tendon cell formation and fibrosis by decreasing Smad7	Cui et al., 2019
			Interfere the PTEN/PI3K/AKT signaling pathway to regulate the biological behavior of cells	Zheng et al., 2017; Yang et al., 2018
		mir-155	Promote the secretion of inflammatory cytokines	Stanczyk et al., 2008; Heymans et al., 2013; Ying et al., 2017
		mir-5106	Inhibit the genes SIK2 and SIK3 to promote bone formation	Xiong et al., 2020
	Alarmins	Annexins	Induce bone resorption and help macrophages to work	Li et al., 2005; D'Souza et al., 2012; Stukes et al., 2016; McArthur et al., 2020; Xia et al., 2020; Xiong et al., 2020
		Galectins	Act on the differentiation of various bone cells	Andersen et al., 2003; Shimura et al., 2005; Nakajima et al., 2014; Weilner et al., 2016; Simon et al., 2017; Iacobini et al., 2018
		HSP; fibronectin	Functions through osteoblasts and osteoclasts.	Moursi et al., 1996; Koh et al., 2009; Gramoun et al., 2010; Notsu et al., 2016; Nakamura et al., 2019