HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Bosco, M. C. Articles by Varesio, L. Search for Related Content PubMed PubMed Citation Articles by Bosco, M. C. Articles by Varesio, L.

The Tryptophan Catabolite Picolinic Acid Selectively Induces the Chemokines Macrophage Inflammatory Protein-1 and -1ß in Macrophages¹

Maria Carla Bosco^2,*, Annamaria Rapisarda^*, Stefano Massazza^*, Giovanni Melillo, Howard Young and Luigi Varesio^*

^* Laboratory of Molecular Biology, G. Gaslini Institute, Genova, Italy; DTP-Tumor Hypoxia Program and Laboratory of Experimental Immunology, National Cancer Institute-Frederick Cancer Research and Development Center, Frederick, MD 21702

We previously found that the tryptophan catabolite picolinic acid (PA) is a costimulus for the activation of macrophage effector functions. In this study, we have investigated the ability of PA to modulate the expression of chemokines in macrophages. We demonstrate that PA is a potent activator of the inflammatory chemokines MIP (macrophage inflammatory protein)-1 and MIP-1ß (MIPs) mRNA expression in mouse macrophages in a dose- and time-dependent fashion and through a de novo protein synthesis-dependent process. The induction by PA occurred within 3 h of treatment and reached a peak in 12 h. The stimulatory effects of PA were selective for MIPs because other chemokines, including monocyte chemoattractant protein-1, RANTES, IFN--inducible protein-10, MIP-2, and macrophage-derived chemokine, were not induced under the same experimental conditions and were not an epiphenomenon of macrophage activation because IFN- did not affect MIPs expression. Induction of both MIP-1 and MIP-1ß by PA was associated with transcriptional activation and mRNA stabilization, suggesting a dual molecular mechanism of control. Iron chelation could be involved in MIPs induction by PA because iron sulfate inhibited the process and the iron-chelating agent, desferrioxamine, induced MIPs expression. We propose the existence of a new pathway leading to inflammation initiated by tryptophan catabolism that can communicate with the immune system through the production of PA, followed by secretion of chemokines by macrophages. These results establish the importance of PA as an activator of macrophage proinflammatory functions, providing the first evidence that this molecule can be biologically active without the need for a costimulatory agent.