Escherichia coli pneumonia enhances granulopoiesis and the mobilization of myeloid progenitor cells into the systemic circulation.
OBJECTIVE
The process by which hematopoietic tissues respond to a pulmonary infection remains poorly understood. This study investigated the potential role of lung-derived granulopoietic cytokines in facilitating this response.


METHODS
Laboratory investigation.


METHODS
University laboratory.


METHODS
Male Balb/c mice.


METHODS
Mice were challenged with intratracheal Escherichia coli or granulocyte colony-stimulating factor (G-CSF). Bone marrow cells were isolated from normal mice and treated in vitro with G-CSF.


RESULTS
Bronchoalveolar lavage fluid concentrations of G-CSF, macrophage inflammatory protein-2, and keratinocyte-derived chemokine were elevated 3 and 6 hrs after intratracheal E. coli. The increases in intrapulmonary G-CSF and keratinocyte-derived chemokine were associated with increases of their concentrations in the plasma. The numbers of granulocyte-macrophage colony forming units in bone marrow, spleen, and blood were increased 48 hrs after intratracheal E. coli or G-CSF. In addition, plasma G-CSF and the number of progenitor cells (lin-ckit+Sca-1(-)) in the blood were increased at 30 mins and 48 hrs, respectively, following intratracheal G-CSF. Signal transducer and activator of transcription-3 in bone marrow cells was activated following intratracheal E. coli or G-CSF in addition to activation by in vitro G-CSF stimulation.


CONCLUSIONS
During pulmonary infection, locally produced cytokines enter the circulation and may play an important role in initiating a granulopoietic response.
Shahbazian
Lotfollah M
LM
Department of Physiology, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA.
Quinton
Lee J
LJ
Bagby
Gregory J
GJ
Nelson
Steve
S
Wang
Guansong
G
Zhang
Ping
P
D000818:Animals; D054426:Chemokine CXCL2; D018925:Chemokines / Q000378:metabolism; D004195:Disease Models, Animal; D004927:Escherichia coli Infections / Q000097:blood* / Q000276:immunology; D016179:Granulocyte Colony-Stimulating Factor / Q000378:metabolism; D006098:Granulocytes / Q000378:metabolism*; D006410:Hematopoiesis; D008168:Lung / Q000276:immunology / Q000378:metabolism; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D015846:Monokines / Q000378:metabolism; D023461:Myeloid Progenitor Cells / Q000378:metabolism*; D010766:Phosphorylation; D018410:Pneumonia, Bacterial / Q000097:blood* / Q000276:immunology
D054426:Chemokine CXCL2; D018925:Chemokines; D015846:Monokines; D016179:Granulocyte Colony-Stimulating Factor