Stolf, B. S. | bioRxiv Science

bioRxiv2023

The protein map of the protozoan parasite Leishmania (Leishmania) amazonensis, Leishmania (Viannia) braziliensis and Leishmania (Leishmania) infantum during growth phase transition and temperature stress

Leishmania parasites cause a spectrum of diseases termed leishmaniasis, which manifests in two main clinical forms, cutaneous and visceral leishmaniasis. Leishmania promastigotes transit from proliferative exponential to quiescent stationary phases inside the insect vector, a relevant step that recapitulates early molecular events of metacyclogenesis. During the insect blood meal of the mammalian hosts, the released parasites interact initially with the skin, an event marked by temperature changes. Deep knowledge on the molecular events activated during Leishmania-host interactions in each step is crucial to develop better therapies and to understand the pathogenesis. In this study, the proteomes of Leishmania (Leishmania) amazonensis (La), Leishmania (Viannia) braziliensis (Lb), and Leishmania (Leishmania) infantum (syn L. L. chagasi) (Lc) were analyzed using quantitative proteomics to uncover the proteome modulation in three different conditions related to growth phases and temperature shifts: 1) exponential phase (Exp); 2) stationary phase (Sta25) and; 3) stationary phase subjected to heat stress (Sta34). Functional validations were performed using orthogonal techniques, focusing on -tubulin, gp63 and heat shock proteins (HSPs). Species-specific and condition-specific modulation highlights the plasticity of the Leishmania proteome, showing that pathways related to metabolism and cytoskeleton are significantly modulated from exponential to stationary growth phases, while protein folding, unfolded protein binding, signaling and microtubule-based movement were differentially altered during temperature shifts. This study provides an in-depth proteome analysis of three Leishmania spp., and contributes compelling evidence of the molecular alterations of these parasites in conditions mimicking the interaction of the parasites with the insect vector and vertebrate hosts.

microbiology↗

bioRxiv2022

Polyamines shift expression of macrophage L-arginine metabolism related-genes during Leishmania amazonensis infection

Polyamines are molecules involved in macrophage activation and polarization in response to pathogens. The interaction with Leishmania promotes modulation of macrophage immune response to favor arginine deviation to polyamines production, leading to parasite survival. Polyamine levels are a potential modulator of growth factors, driving cells to proliferation, wound healing, oxidative stress, or regulating translation. Here, we investigate the impact of L-arginine and polyamines in the transcriptional regulation of genes involved in arginine metabolization and pro-inflammatory response to L. amazonensis in murine BALB/c macrophages. We found that supplementation with L-arginine is insufficient to modulate macrophage gene expression and infection. Polyamine supplementation altered nitric oxide synthase (Nos2) and nitric oxide (NO) production, as well as other macrophage enzymes. Putrescine supplementation increased transcript levels of polyamine metabolism-related genes Arginase 2 (Arg2), Spermidine synthase (SpdS), and Spermine synthase (SpmS) in both uninfected and L. amazonensis infected macrophages. Putrescine increased Nos2 expression without leading to NO production, while L-arginine plus spermine led to production of NO in uninfected macrophages. Besides, L-arginine supplementation reduced the levels of Il-1b during infection, and L-arginine or L-arginine plus putrescine increased Mcp1 at 24h of infection. The percentage of infected macrophages was lower after putrescine, spermidine, and spermine supplementation than L-arginine supplementation. Our data showed that the polyamines shift L-arginine-metabolism related-genes on BALB/c macrophages and affect infection by L. amazonensis.

molecular biology↗