title: In vivo phenotypic characterisation of nucleoside label-retaining cells in mouse periosteum.
abstract: Periosteum is known to contain cells that, after isolation and culture-expansion, display properties of mesenchymal stromal/stem cells (MSCs). However, the equivalent cells have not been identified in situ mainly due to the lack of specific markers. Postnatally, stem cells are slow-cycling, long-term nucleoside-label-retaining cells. This study aimed to identify and characterise label-retaining cells in mouse periosteum in vivo. Mice received iodo-deoxy-uridine (IdU) via the drinking water for 30 days, followed by a 40-day washout period. IdU+ cells were identified by immunostaining in conjunction with MSC and lineage markers. IdU-labelled cells were detected throughout the periosteum with no apparent focal concentration, and were negative for the endothelial marker von Willebrand factor and the pan-haematopoietic marker CD45. Subsets of IdU+ cells were positive for the mesenchymal/stromal markers vimentin and cadherin-11. IdU+ cells expressed stem cell antigen-1, CD44, CD73, CD105, platelet-derived growth factor receptor-α and p75, thereby displaying an MSC-like phonotype. Co-localisation was not detectable between IdU and the pericyte markers CD146, alpha smooth muscle actin or NG2, nor did IdU co-localise with β-galactosidase in a transgenic mouse expressing this reporter gene in pericytes and smooth muscle cells. Subsets of IdU+ cells expressed the osteoblast-lineage markers Runx2 and osteocalcin. The IdU+ cells expressing osteocalcin were lining the bone and were negative for the MSC marker p75. In conclusion, mouse periosteum contains nucleoside-label-retaining cells with a phenotype compatible with MSCs that are distinct from pericytes and osteoblasts. Future studies characterising the MSC niche in vivo could reveal novel therapeutic targets for promoting bone regeneration/repair.
authors.affiliation: Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD, Scotland, UK.c.debari@abdn.ac.uk.
authors.forename: H M
authors.initials: HM
authors.lastname: Cherry
authors.forename: A J
authors.initials: AJ
authors.lastname: Roelofs
authors.forename: T B
authors.initials: TB
authors.lastname: Kurth
authors.forename: C
authors.initials: C
authors.lastname: De Bari
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000235:genetics / Q000378:metabolism; D015820:Cadherins / Q000235:genetics / Q000378:metabolism; D019070:Cell Lineage; D050659:Core Binding Factor Alpha 1 Subunit / Q000235:genetics / Q000378:metabolism; D007065:Idoxuridine / Q000493:pharmacokinetics*; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000378:metabolism; D051379:Mice; D010006:Osteoblasts / Q000166:cytology / Q000378:metabolism; D015675:Osteocalcin / Q000235:genetics / Q000378:metabolism; D020286:Pericytes / Q000166:cytology / Q000378:metabolism; D010521:Periosteum / Q000166:cytology* / Q000378:metabolism; D010641:Phenotype; D014018:Tissue Distribution; D014746:Vimentin / Q000235:genetics / Q000378:metabolism; D014841:von Willebrand Factor / Q000235:genetics / Q000378:metabolism
chemical_list: D015703:Antigens, CD; D015820:Cadherins; D050659:Core Binding Factor Alpha 1 Subunit; C493716:Runx2 protein, mouse; D014746:Vimentin; D014841:von Willebrand Factor; D015675:Osteocalcin; C086960:osteoblast cadherin; D007065:Idoxuridine