title: Extended time-lapse in vivo imaging of tibia bone marrow to visualize dynamic hematopoietic stem cell engraftment.
abstract: Homing, engraftment and proliferation of hematopoietic stem/progenitor cell (HSC/HPCs) are crucial steps required for success of a bone marrow transplant. Observation of these critical events is limited by the opaque nature of bone. Here we demonstrate how individual HSCs engraft in long bones by thinning one side of the tibia for direct and unbiased observation. Intravital imaging enabled detailed visualization of single Sca-1+, c-Kit+, Lineage-(SKL) cell migration to bone marrow niches and subsequent proliferation to reconstitute hematopoiesis. This longitudinal study allowed direct observation of dynamic HSC/HPC activities during engraftment in full color for up to 6 days in live recipients. Individual SKL cells, but not mature or committed progenitor cells, preferentially homed to a limited number of niches near highly vascularized endosteal regions, and clonally expanded. Engraftment of SKL cells in P-selectin and osteopontin knockout mice showed abnormal homing and expansion of SKL cells. CD150+, CD48-SKL populations initially engrafted in the central marrow region, utilizing only a subset of niches occupied by the parent SKL cells. Our study demonstrates that time-lapse imaging of tibia can be a valuable tool to understand the dynamic characteristics of functional HSC and niche components in various mouse models.
authors.affiliation: Program in Stem Cell Biology and Regenerative Medicine, University of Florida College of Medicine, Gainesville, FL, USA.|Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL, USA.|Department of Physiology and Functional Genomics, University of Florida, Gainesville, FL, USA.
authors.forename: S
authors.initials: S
authors.lastname: Kim
authors.affiliation: Program in Stem Cell Biology and Regenerative Medicine, University of Florida College of Medicine, Gainesville, FL, USA.|Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL, USA.
authors.forename: L
authors.initials: L
authors.lastname: Lin
authors.affiliation: Program in Stem Cell Biology and Regenerative Medicine, University of Florida College of Medicine, Gainesville, FL, USA.|Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL, USA.
authors.forename: G A J
authors.initials: GAJ
authors.lastname: Brown
authors.affiliation: Department of Neurosurgery, University of Florida, Gainesville, FL, USA.
authors.forename: K
authors.initials: K
authors.lastname: Hosaka
authors.affiliation: Program in Stem Cell Biology and Regenerative Medicine, University of Florida College of Medicine, Gainesville, FL, USA.|Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL, USA.
authors.forename: E W
authors.initials: EW
authors.lastname: Scott
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells / Q000502:physiology*; D002465:Cell Movement; D049109:Cell Proliferation; D018380:Hematopoietic Stem Cell Transplantation; D051379:Mice; D008810:Mice, Inbred C57BL; D053495:Osteopontin / Q000502:physiology; D055153:Stem Cell Niche / Q000502:physiology; D013977:Tibia / Q000166:cytology*
chemical_list: D053495:Osteopontin