title: Matrix metalloproteinases in stem cell mobilization.
abstract: Hematopoietic stem cells (HSCs) have the capability to migrate back and forth between their preferred microenvironment in bone marrow niches and the peripheral blood, but under steady-state conditions only a marginal number of stem cells can be found in the circulation. Different mobilizing agents, however, which create a highly proteolytic milieu in the bone marrow, can drastically increase the number of circulating HSCs. Among other proteases secreted and membrane-bound matrix metalloproteinases (MMPs) are known to be involved in the induced mobilization process and can digest niche-specific extracellular matrix components and cytokines responsible for stem cell retention to the niches. Iatrogenic stem cell mobilization and stem cell homing to their niches are clinically employed on a routine basis, although the exact mechanisms of both processes are still not fully understood. In this review we provide an overview on the various roles of MMPs in the induced release of HSCs from the bone marrow.
authors.affiliation: Center for Medical Research, Department of Internal Medicine, Section for Transplantation Immunology and Immunohematology, University of Tübingen, Germany. Electronic address: gerd.klein@uni-tuebingen.de.
authors.forename: Gerd
authors.initials: G
authors.lastname: Klein
authors.affiliation: Center for Medical Research, Department of Internal Medicine, Section for Transplantation Immunology and Immunohematology, University of Tübingen, Germany.
authors.forename: Olga
authors.initials: O
authors.lastname: Schmal
authors.affiliation: Department of Urology, University of Tübingen, Germany.
authors.forename: Wilhelm K
authors.initials: WK
authors.lastname: Aicher
mesh_terms: D000818:Animals; D016207:Cytokines / Q000378:metabolism; D016326:Extracellular Matrix Proteins; D019650:Hematopoietic Stem Cell Mobilization; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000502:physiology*; D006801:Humans; D020782:Matrix Metalloproteinases / Q000378:metabolism*; D055153:Stem Cell Niche
chemical_list: D016207:Cytokines; D016326:Extracellular Matrix Proteins; D020782:Matrix Metalloproteinases
keywords: extracellular matrix; hematopoietic stem cells; proteolytic microenvironment; stem cell homing; stem cell niche