title: Deep imaging of bone marrow shows non-dividing stem cells are mainly perisinusoidal.
abstract: Haematopoietic stem cells (HSCs) reside in a perivascular niche but the specific location of this niche remains controversial. HSCs are rare and few can be found in thin tissue sections or upon live imaging, making it difficult to comprehensively localize dividing and non-dividing HSCs. Here, using a green fluorescent protein (GFP) knock-in for the gene Ctnnal1 in mice (hereafter denoted as α-catulin(GFP)), we discover that α-catulin(GFP) is expressed by only 0.02% of bone marrow haematopoietic cells, including almost all HSCs. We find that approximately 30% of α-catulin-GFP(+)c-kit(+) cells give long-term multilineage reconstitution of irradiated mice, indicating that α-catulin-GFP(+)c-kit(+) cells are comparable in HSC purity to cells obtained using the best markers currently available. We optically cleared the bone marrow to perform deep confocal imaging, allowing us to image thousands of α-catulin-GFP(+)c-kit(+) cells and to digitally reconstruct large segments of bone marrow. The distribution of α-catulin-GFP(+)c-kit(+) cells indicated that HSCs were more common in central marrow than near bone surfaces, and in the diaphysis relative to the metaphysis. Nearly all HSCs contacted leptin receptor positive (Lepr(+)) and Cxcl12(high) niche cells, and approximately 85% of HSCs were within 10 μm of a sinusoidal blood vessel. Most HSCs, both dividing (Ki-67(+)) and non-dividing (Ki-67(-)), were distant from arterioles, transition zone vessels, and bone surfaces. Dividing and non-dividing HSCs thus reside mainly in perisinusoidal niches with Lepr(+)Cxcl12(high) cells throughout the bone marrow.
authors.affiliation: Children's Research Institute and the Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA.
authors.forename: Melih
authors.initials: M
authors.lastname: Acar
authors.affiliation: Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA.|Children's Research Institute and the Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA.
authors.forename: Kiranmai S
authors.initials: KS
authors.lastname: Kocherlakota
authors.affiliation: Children's Research Institute and the Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA.
authors.forename: Malea M
authors.initials: MM
authors.lastname: Murphy
authors.affiliation: Children's Research Institute and the Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA.
authors.forename: James G
authors.initials: JG
authors.lastname: Peyer
authors.affiliation: Children's Research Institute and the Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA.
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Oguro
authors.affiliation: Children's Research Institute and the Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA.
authors.forename: Christopher N
authors.initials: CN
authors.lastname: Inra
authors.affiliation: Children's Research Institute and the Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA.
authors.forename: Christabel
authors.initials: C
authors.lastname: Jaiyeola
authors.affiliation: Children's Research Institute and the Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA.
authors.forename: Zhiyu
authors.initials: Z
authors.lastname: Zhao
authors.affiliation: Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA.
authors.forename: Katherine
authors.initials: K
authors.lastname: Luby-Phelps
authors.affiliation: Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA.|Children's Research Institute and the Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA.
authors.forename: Sean J
authors.initials: SJ
authors.lastname: Morrison
mesh_terms: D000818:Animals; D001160:Arterioles / Q000378:metabolism; D015415:Biomarkers / Q000032:analysis / Q000378:metabolism; D001853:Bone Marrow / Q000033:anatomy & histology*; D002455:Cell Division; D019070:Cell Lineage; D054377:Chemokine CXCL12 / Q000378:metabolism; D018483:Diaphyses / Q000166:cytology / Q000378:metabolism; D005260:Female; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000378:metabolism*; D007091:Image Processing, Computer-Assisted; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018613:Microscopy, Confocal; D057054:Molecular Imaging; D019009:Proto-Oncogene Proteins c-kit / Q000378:metabolism; D054411:Receptors, Leptin / Q000378:metabolism; D055153:Stem Cell Niche; D013977:Tibia / Q000033:anatomy & histology / Q000098:blood supply / Q000166:cytology; D051178:alpha Catenin / Q000032:analysis / Q000378:metabolism
chemical_list: D015415:Biomarkers; D054377:Chemokine CXCL12; C515256:Cxcl12 protein, mouse; D054411:Receptors, Leptin; D051178:alpha Catenin; D019009:Proto-Oncogene Proteins c-kit