Journal of Experimental Medicine 2014-06-02

Regulation of mammalian siderophore 2,5-DHBA in the innate immune response to infection.

Zhuoming Liu, Scott Reba, Wei-Dong Chen, Suheel Kumar Porwal, W Henry Boom, Robert B Petersen, Roxana Rojas, Rajesh Viswanathan, L Devireddy

Index: J. Exp. Med. 211(6) , 1197-213, (2014)

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Abstract

Competition for iron influences host-pathogen interactions. Pathogens secrete small iron-binding moieties, siderophores, to acquire host iron. In response, the host secretes siderophore-binding proteins, such as lipocalin 24p3, which limit siderophore-mediated iron import into bacteria. Mammals produce 2,5-dihydroxy benzoic acid, a compound that resembles a bacterial siderophore. Our data suggest that bacteria use both mammalian and bacterial siderophores. In support of this idea, supplementation with mammalian siderophore enhances bacterial growth in vitro. In addition, mice lacking the mammalian siderophore resist E. coli infection. Finally, we show that the host responds to infection by suppressing siderophore synthesis while up-regulating lipocalin 24p3 expression via TLR signaling. Thus, reciprocal regulation of 24p3 and mammalian siderophore is a protective mechanism limiting microbial access to iron. © 2014 Liu et al.