Authors

Discussion

Polyamines are important molecules involved in cell growth, direct DNA interaction, TCA cycle, and in macrophages, they can play a function on activation and polarization in response to pathogens. The mechanism to control Leishmania infection relies on a balance between the conversion of arginine into nitric oxide (NO) to kill the parasite and the arginine conversion into ornithine and subsequent into polyamines putrescine, spermidine, and spermine, necessary for parasite survival. In this work, we ask whether polyamine availability can act in gene expression and immune response of BALB/c macrophages during 4 and 24 hours of infection with L. amazonensis.  Transcripts of Slc3a2, a polycation transporter, reduced expression in uninfected macrophages supplemented with arginine plus spermidine or spermidine only after 24h, compared to arginine supplementation. Transcript levels of other host cationic and neutral amino acid transporters were not modified under conditions of arginine and polyamines supplementation in macrophages. The host arginase 2 (Arg2) mRNA levels were increased in supplementation with putrescine in infected macrophages at 4h. The levels of Nos2 mRNA were increased in supplemented with putrescine and infected macrophages at 4h, which did not reflect in NO production. Regarding some proinflammatory cytokines, the levels of Il-1b mRNA increased in uninfected macrophages supplemented with spermidine and spermine after 24h, but did not alter the expression of Tnfa. The levels of Mcp1 increased in infected macrophages supplemented with arginine plus putrescine or putrescine only at 24h. The percentage of infected macrophages was lower in putrescine, spermidine and spermine supplementation than arginine supplementation, reducing the infection index. These data indicated that the availability of polyamines could interfere in gene expression of arginine pathways and immune response in macrophages during L. amazonensis infection.