Innate immunity as orchestrator of stem cell mobilization.
Hematopoietic stem and progenitor cells (HSPCs), as well as other types of stem cells, circulate under steady-state conditions at detectable levels in peripheral blood (PB), with their numbers increasing in response to stress, inflammation and tissue/organ injury. This mobilization process may be envisioned as a danger-sensing response mechanism triggered by hypoxia or mechanical or infection-induced tissue damage that recruits into PB different types of stem cells that have a role in immune surveillance and organ/tissue regeneration. Mobilization is also significantly enhanced by the administration of pharmacological agents, which has been exploited in hematological transplantology as a means to obtain HSPCs for hematopoietic reconstitution. In this review we will present mounting evidence that innate immunity orchestrates this evolutionarily conserved mechanism of HSPC mobilization.
Ratajczak
M Z
MZ
Stem Cell Biology Program at the James Graham Brown Cancer Center, University of Louisville, Louisville, KY 40202, USA. mzrata01@louisville.edu
Kim
C H
CH
Wojakowski
W
W
Janowska-Wieczorek
A
A
Kucia
M
M
Ratajczak
J
J
D006402:Hematologic Diseases / Q000276:immunology*; D019650:Hematopoietic Stem Cell Mobilization; D006801:Humans; D007113:Immunity, Innate; D033581:Stem Cell Transplantation; D013234:Stem Cells / Q000166:cytology / Q000276:immunology*