C/EBPβ is involved in the amplification of early granulocyte precursors during candidemia-induced «emergency» granulopoiesis.

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C/EBPβ is involved in the amplification of early granulocyte precursors during candidemia-induced "emergency" granulopoiesis.

J Immunol. 2012 Nov 1;189(9):4546-55

Authors: Satake S, Hirai H, Hayashi Y, Shime N, Tamura A, Yao H, Yoshioka S, Miura Y, Inaba T, Fujita N, Ashihara E, Imanishi J, Sawa T, Maekawa T

Abstract
Granulopoiesis is tightly regulated to meet host demands during both "steady-state" and "emergency" situations, such as infections. The transcription factor CCAAT/enhancer binding protein β (C/EBPβ) plays critical roles in emergency granulopoiesis, but the precise developmental stages in which C/EBPβ is required are unknown. In this study, a novel flow cytometric method was developed that successfully dissected mouse bone marrow cells undergoing granulopoiesis into five distinct subpopulations (#1-5) according to their levels of c-Kit and Ly-6G expression. After the induction of candidemia, rapid mobilization of mature granulocytes and an increase in early granulocyte precursors accompanied by cell cycle acceleration was followed by a gradual increase in granulocytes originating from the immature populations. Upon infection, C/EBPβ was upregulated at the protein level in all the granulopoietic subpopulations. The rapid increase in immature subpopulations #1 and #2 observed in C/EBPβ knockout mice at 1 d postinfection was attenuated. Candidemia-induced cell cycle acceleration and proliferation of hematopoietic stem/progenitors were also impaired. Taken together, these data suggest that C/EBPβ is involved in the efficient amplification of early granulocyte precursors during candidemia-induced emergency granulopoiesis.

PMID: 23024276 [PubMed - indexed for MEDLINE]