Dados do Trabalho

Título

Iron and heme status at the Leishmania-host interface: effect of iron deficiency anemia on the Leishmania (L.) amazonensis virulence

Introdução

Leishmaniases, a spectrum of diseases caused by protozoan parasites of the genus Leishmania, affect millions of people worldwide. During infection, nutrient availability within the phagolysosomes has significant effects on parasite replication and virulence. This process requires the acquisition of essential nutrients such as iron and heme from the host since Leishmania does not have iron storage proteins or the capacity to synthesize heme. As well, free iron and heme are cytotoxic due to the generation of free radicals in the presence of oxygen. Leishmania, therefore, must acquire heme and iron to survive in a hostile environment that restricts the availability of nutrients to the pathogen, a process called nutritional immunity. Identification of several proteins involved in the iron and heme transport was crucial for understanding these metabolic pathways in Leishmania.

Objetivo (s)

To investigate the cross-regulation between iron and heme transporters, LIT1 and LHR1, and the effect of host iron and heme availability on L. amazonensis infection.

Material e Métodos

We generated mutants overexpressing GFP-tagged LIT1 and LHR1 in wild-type (WT) and LHR1 SKO lines via homologous recombination. These mutants were characterized regarding intracellular heme levels via the PPIX-fluorescence method. The growth profile was evaluated to assess the impact of heme depletion on mutant promastigotes. In vitro infectivity of those mutants is being evaluated by BMDMs infection. The consequence of iron deficiency anemia on L. amazonensis infection in mice was evaluated by feeding mice with a low-iron diet. Lesions were measured weekly and hematocrit levels were measured bi-weekly.

Resultados e Conclusão

Promastigote growth profile in heme-depleted conditions suggested that LIT1 overexpression may compensate for the loss of one LHR1 allele. Besides, numerous unsuccessful attempts to generate LIT1 KO lines by CRISPR-Cas9 indicate that, despite previous publications, this gene may be essential. Regarding in vivo experiments, iron-deficient anemic mice developed smaller lesions when infected with WT parasites compared to healthy mice. Our findings could contribute to in-depth knowledge of iron and heme metabolism pathways and unveil the importance of nutritional immunity on leishmaniases.

Palavras-chave

leishmaniases, host-parasite interaction, nutritional immunity

Agradecimentos

FAPESP, CNPq