title: The lineage-c-Kit+Sca-1+ cell response to Escherichia coli bacteremia in Balb/c mice.
abstract: During bacterial infection, the bone marrow hematopoietic activity shifts toward granulocyte production, which is critical for host defenses. Along with this enhancement of granulopoiesis, the bone marrow also increases its release of hematopoietic precursors. At the present time, little is known about the commitment of hematopoietic precursor cells, including hematopoietic stem cells and progenitors, in this response. To investigate the hematopoietic precursor cell response to bacterial infection, bacteremia was established in Balb/c mice by i.v. injection of Escherichia coli. Bacteremia caused a 10-fold increase in the number of lineage (lin)-c-kit+Sca-1+ cells in the bone marrow. This dramatic expansion of the lin-c-kit+Sca-1+ cell pool resulted from both increased mitosis of these cells and inversion from lin-c-kit+Sca-1- cell phenotype. Lipopolysaccharide, tumor necrosis factor-alpha, and interleukin-6 were potent factors capable of mediating phenotypic inversion of lin-c-kit+Sca-1- cells. Cells in the expanded lin-c-kit+Sca-1+ cell pool contained more colony-forming unit-granulocyte/macrophage. Mobilization of lin-c-kit+Sca-1+ cells into the circulation was significantly enhanced following bacteremia. These results demonstrate that the lin-c-kit+Sca-1+ cell population in the bone marrow constitutes a key component of the host defense response to bacteremia. Functional modifications of these primitive hematopoietic precursors are critical for enhancing granulocyte production following bacterial infection.
authors.affiliation: Department of Medicine, Section of Pulmonary/Critical Care Medicine, LSU Health Sciences Center, New Orleans, Louisiana 70112-1393, USA. pzhang@lsuhsc.edu
authors.forename: Ping
authors.initials: P
authors.lastname: Zhang
authors.forename: Steve
authors.initials: S
authors.lastname: Nelson
authors.forename: Gregory J
authors.initials: GJ
authors.lastname: Bagby
authors.forename: Robert
authors.initials: R
authors.lastname: Siggins
authors.forename: Judd E
authors.initials: JE
authors.lastname: Shellito
authors.forename: David A
authors.initials: DA
authors.lastname: Welsh
mesh_terms: D000818:Animals; D000950:Antigens, Ly / Q000096:biosynthesis*; D016470:Bacteremia / Q000378:metabolism*; D001854:Bone Marrow Cells / Q000166:cytology; D002454:Cell Differentiation; D019070:Cell Lineage; D004926:Escherichia coli / Q000378:metabolism*; D004927:Escherichia coli Infections / Q000378:metabolism*; D006412:Hematopoietic Stem Cells / Q000166:cytology; D008297:Male; D008565:Membrane Proteins / Q000096:biosynthesis*; D051379:Mice; D008807:Mice, Inbred BALB C; D010641:Phenotype; D019009:Proto-Oncogene Proteins c-kit / Q000096:biosynthesis*; D013234:Stem Cells
chemical_list: D000950:Antigens, Ly; C074650:Ly6a protein, mouse; D008565:Membrane Proteins; D019009:Proto-Oncogene Proteins c-kit