Polimorfismos genéticos envolvidos no estresse oxidativo na leishmaniose cutânea por Leishmania guyanensis no estado do Amazonas

Abstract

Background: The Leishmania parasite has the ability to survive and replicate in the macrophage. These characteristics probably evolved as a Leishmania resistance strategy against inflammatory cells. During Leishmania infection, macrophages and neutrophils phagocytose the parasites, forming the phagosome, where they are “bombarded” by an “oxidizing cascade” containing especially ROS. This process contains mainly superoxide (O2•-) and hydrogen peroxide (H2O2) forming a complex known as “oxidative explosion”. To this end, our objective was to investigate genetic polymorphisms in genes involved in oxidative stress in patients with cutaneous leishmaniasis (CL) infected by L. (Viannia) guyanensis using a case-control study model. Methods: Patients with CL treated at FMT-HVD and healthy individuals, with no signs or history of leishmaniasis, living in the same location as the Cases, were recruited. plasma chemokines and cytokines were measured using the Luminex technique and the polymorphisms measured using real-time PCR (qPCR) by TaqMan® system, analyzed on QuantStudio 6 platform (Applied Biosystems). Results: A total of 768 patients and 744 healthy volunteers agreed to participate in the study. The homozygous wild genotype (WT) c.-262CC in Catalase (OD: 1.29 - p=0.041) and WT SOD2 c.47CC were associated as a risk factor for CL, while WT MPO c.-463GG (OD: 0 .73 - p=0.004); WT NOX2 c.242CC (OD: 0.74 - p=0.005); WT NOS3 c.-786TT (OD: 0.75 - p=0.008); WT TGF-ß1 c.-509CC (OD: 0.63 - p<0.001) associated as a protective factor. The NOS2 c.-954G>C SNP did not show significant associations. IL-13 and MCP-1 were the main associated cytokines strongly reduced in patients in the presence of mutant genotypes compared to WT. It is worth noting that plasma INF-γ concentrations were significantly reduced in mutant genotypes of almost all SNPs in CL patients. Conclusions: We consider that the mutant genotypes decreased the main neutrophil-activating cytokines, being IL-2 (MPO c.-463AA, TGF-ß1 c.-509TT and SOD2 c.47TT); IL-8 (CAT c.-262TT, TGF-ß1 c.-509TT and SOD2 c.47TT) and IL-12 (CAT c.-262TT and NOS3 c.-786CC), suggesting lower ROS concentration, decreased stress oxidative activity and greater disease progression in these mutant genotypes. The mutant genotypes (CAT c.-262TT, NOX2 c.242TT, TGF-ß1 c.-509TT and SOD2 c.47TT) resulted in a decrease in INF-γ, suggesting lower production of inflammatory cytokines and disease progression in these genotypes. While the CAT c.-262CC genotype decreased the levels of IL-10 and IL-17, which may be associated with the elimination of the Leishmania parasite. The cytokines IL-6, IL-13, IL-1B, FGF-Basic are produced by macrophages, dendritic cells and lymphocytes. These cytokines play a

vital role in susceptibility to leishmaniasis. The homozygous mutant genotypes of TGF- ß1 c.-509TT and SOD2 c.47TT were associated with decreased levels of these cytokines

in patients. Therefore, these cytokines may be associated with both the progression and elimination of the disease. Our findings demonstrated the genotypes (WT MPO c.- 463GG, WT NOX2 c.242CC, WT NOS3 c.-786TT and WT TGF-ß1 c.-509CC) with greater ROS production and thus proved to be protective factors for LC. While the WT CAT c.-262CC and SOD2 c.47CC genotypes demonstrated the lowest production of ROS, suggesting themselves as a risk factor for Cutaneous Leishmaniasis.