The Cysteine-Cysteine Family of Chemokines RANTES, MIP-1α, and MIP-1β Induce Trypanocidal Activity in Human Macrophages via Nitric Oxide

Abstract

This paper describes a new role for the cysteine-cysteine (CC) chemokines RANTES, MIP-1α, and MIP-1β on human macrophage function, which is the induction of nitric oxide (NO)-mediated trypanocidal activity. In a previous report, we showed that RANTES, MIP-1α and MIP-1β enhance Trypanosoma cruzi uptake and promote parasite killing by human macrophages (M. F. Lima, Y. Zhang, and F. Villalta, Cell. Mol. Biol. 43:1067–1076, 1997). Here we study the mechanism by which RANTES, MIP-1α, and MIP-1β activate human macrophages obtained from healthy individuals to kill T. cruzi. Treatment of human macrophages with different concentrations of RANTES, MIP-1α, and MIP-1β enhances T. cruzi trypomastigote phagocytosis in a dose peak response. The optimal response induced by the three CC chemokines is attained at 500 ng/ml. The macrophage trypanocidal activity induced by CC chemokines can be completely inhibited by l-N-monomethyl arginine (l-NMMA), a specific inhibitor of thel-arginine:NO pathway, but not by itsd-enantiomer. Culture supernatants of chemokine-treated human macrophages contain increased NO2 −levels, and NO2 − production is also specifically inhibited by l-NMMA. The amount of NO2 − induced by these chemokines in human macrophages is comparable to the amount of NO2 − induced by gamma interferon. The killing of trypomastigotes by NO in cell-free medium is blocked by an NO antagonist or a NO scavenger. This data supports the hypothesis that the CC chemokines RANTES, MIP-1α, and MIP-1β activate human macrophages to kill T. cruzi via NO, which is an effective trypanocidal mechanism.

CCR5 Plays a Critical Role in the Development of Myocarditis and Host Protection in Mice Infected withTrypanosoma cruzi

“…It is now clear that IFN-g-and TNF-a-activated macrophages control of the replication of T. cruzi in various hosts [20]. The mechanism by which macrophages are able to kill intracellular parasites has been shown to be dependent on NO [8][9][10][11][12][13]20], although a recent study using T. cruzi strains Tulahuen and Brazil suggested that inducible NO synthase (iNOS) is not required to control parasite replication in vivo [21]. However, much less is known about the mechanisms governing the migration of leukocytes to sites of tissue infection, especially to hearts of infected hosts.…”

“…Infection of macrophages [9] and cardiomyocytes [10] with T. cruzi trypomastigote forms is accompanied by the significant production of several chemokines, including CCL3, CCL4, and CCL5. Not only can the latter cells produce chemokines, but chemokines can also act on the cells to induce iNOS expression, NO expression, and the killing of parasites [9][10][11][12][13]. Thus, in the present study, it was important to ascertain whether chemokine expression would also occur in vivo after infection of mice with the Y strain of T. cruzi.…”

“…We recently reported that T. cruzi-infected macrophages and cardiomyocytes expressed mRNA for a range of chemokines, including CCL3 (macrophage inflammatory protein [MIP]-1a), CCL4 (MIP-1b), and CCL5 (RANTES) [9,10]. In these studies, not only were these chemokines expressed, but T. cruzi-infected macrophages and cardiomyocytes also expressed NO, to mediate NO-dependent killing in vitro [9][10][11][12][13]. Moreover, we showed that mRNA for these chemokines was also expressed during acute infection in mice and that cytokines (i.e., TNF-a and IFN-g) known to participate in the control of infection modulated the expression of chemokines [14][15][16].…”

Does myoglobin protect Trypanosoma cruzi from the antiparasitic effects of nitric oxide?1

“…MbO 2 (Fe(II)O 2 ) reacts rapidly with NO to yield nitrate (NO 3 3 ) and metMb (Fe(III)) [20]. Moreover, de-oxyMb (Fe(II)) binds NO yielding MbNO (Fe(II)NO) which in the presence of O 2 may be converted to metMb (Fe(III)) and NO 3 3 [23]. These reactions quench free NO, which may inactivate cysteine-containing and metallo-enzymes [2,16,24].…”

“…NO detoxi¢cation facilitated by Mb may thus protect T. cruzi colonizing the cardiomyocytes from the adverse e¡ects of NO. NO may bind also to metMb (Fe(III)) yielding metMbNO (Fe(III)NO), which in the presence of metMb reductase and O 2 may be converted to metMb (Fe(III)) and NO 3 3 . However, this process does not appear of physiological relevance, being thermodynamically and kinetically unfavorable [19,232 5].…”