[PDF][PDF] Granulocyte macrophage-colony stimulating factor induced Zn sequestration enhances macrophage superoxide and limits intracellular pathogen survival

KS Vignesh, JAL Figueroa, A Porollo, JA Caruso… - Immunity, 2013 - cell.com
Immunity, 2013cell.com
Macrophages possess numerous mechanisms to combat microbial invasion, including
sequestration of essential nutrients, like zinc (Zn). The pleiotropic cytokine granulocyte
macrophage-colony stimulating factor (GM-CSF) enhances antimicrobial defenses against
intracellular pathogens such as Histoplasma capsulatum, but its mode of action remains
elusive. We have found that GM-CSF-activated infected macrophages sequestered labile Zn
by inducing binding to metallothioneins (MTs) in a STAT3 and STAT5 transcription-factor …
Summary
Macrophages possess numerous mechanisms to combat microbial invasion, including sequestration of essential nutrients, like zinc (Zn). The pleiotropic cytokine granulocyte macrophage-colony stimulating factor (GM-CSF) enhances antimicrobial defenses against intracellular pathogens such as Histoplasma capsulatum, but its mode of action remains elusive. We have found that GM-CSF-activated infected macrophages sequestered labile Zn by inducing binding to metallothioneins (MTs) in a STAT3 and STAT5 transcription-factor-dependent manner. GM-CSF upregulated expression of Zn exporters, Slc30a4 and Slc30a7; the metal was shuttled away from phagosomes and into the Golgi apparatus. This distinctive Zn sequestration strategy elevated phagosomal H+ channel function and triggered reactive oxygen species generation by NADPH oxidase. Consequently, H. capsulatum was selectively deprived of Zn, thereby halting replication and fostering fungal clearance. GM-CSF mediated Zn sequestration via MTs in vitro and in vivo in mice and in human macrophages. These findings illuminate a GM-CSF-induced Zn-sequestration network that drives phagocyte antimicrobial effector function.
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