TABLE 1.

Characteristics and functions of perivascular cell types in bone marrow.

Cell type	Blood vessel niche	Markers	Functions	References
LepR+ Stromal Cells	Type-L	LepR, Angpt1, PDGFRα	Give rise to bone cells and adipocytes; proliferate after injury to regenerate bone	Sacchetti et al., 2007; Ono et al., 2014; Zhou et al., 2014, 2015; Ramasamy, 2017
Cxcl12-Abundant Reticular (CAR) Cells	Type-L	Cxcl12, SCF, PDGFRβ, Foxc1, LepR, PDGFRα	Supportive niche for HSCs; give rise to adipocyte and osteoblast lineages	Sugiyama and Nagasawa, 2012; Ding and Morrison, 2013; Omatsu et al., 2014
Adipocytes	Type-L	Perilipin, PPARγ, adiponectin, FABP4, LPL	Endocrine secretion; lipid metabolism; HSC regulation	Cawthorn et al., 2014; Bukowska et al., 2018
Osteoprogenitors	Type-H	Osterix, Runx2	Give rise to osteoblasts in adults	Kusumbe et al., 2014; Ramasamy, 2017
Periarteriolar/Nestin+ MSCs	Type-H, Arteriole	Nestin-GFP, PDGFRβ, NG2, PDGFRα, CD51, CD146, CXCL12, SCF	Give rise to multiple mesenchymal lineages, including osteoprogenitors; supportive niche for HSCs; promote HSC quiescence	Méndez-Ferrer et al., 2010; Kunisaki et al., 2013; Pinho et al., 2013; Itkin et al., 2016; Kusumbe et al., 2016; Ramasamy, 2017
Smooth Muscle Cells	Arteriole, Artery	α-SMA	Regulate arterial vasomotor functions	Lund et al., 2013; Kusumbe et al., 2014; Ramasamy, 2017