RESUMO

Orbital biopsy of nonspecific orbital inflammation, commonly referred to as "orbital pseudotumor," typically shows a combination of polyclonal lymphocytes, plasmocytes, leukocytes, macrophages, and variable degrees of collagen deposition. Herein, we report a patient with a positive history of mucocutaneous leishmaniasis who presented with an orbital mass with a histological profile of idiopathic orbital inflammation. Immunohistochemical and molecular analysis of the orbital specimens demonstrated that the orbital inflammation was associated with the presence of antigens of Leishmania braziliensis and DNA from the parasite.

Assuntos

Leishmania braziliensis/isolamento & purificação , Pseudotumor Orbitário/parasitologia , Idoso , Humanos , Masculino , Pseudotumor Orbitário/patologia , Pseudotumor Orbitário/cirurgia

RESUMO

BACKGROUND: Leishmaniasis is a complex disease in which clinical outcome depends on factors such as parasite species, host genetics and immunity and vector species. In Brazil, Leishmania (Viannia) braziliensis is a major etiological agent of cutaneous (CL) and mucosal leishmaniasis (MCL), a disfiguring form of the disease, which occurs in ~10% of L. braziliensis-infected patients. Thus, clinical isolates from patients with CL and MCL may be a relevant source of information to uncover parasite factors contributing to pathogenesis. In this study, we investigated two pairs of L. (V.) braziliensis isolates from mucosal (LbrM) and cutaneous (LbrC) sites of the same patient to identify factors distinguishing parasites that migrate from those that remain at the primary site of infection. METHODOLOGY/PRINCIPAL FINDINGS: We observed no major genomic divergences among the clinical isolates by molecular karyotype and genomic sequencing. RT-PCR revealed that the isolates lacked Leishmania RNA virus (LRV). However, the isolates exhibited distinct in vivo pathogenesis in BALB/c mice; the LbrC isolates were more virulent than the LbrM isolates. Metabolomic analysis revealed significantly increased levels of 14 metabolites in LbrC parasites and 31 metabolites in LbrM parasites that were mainly related to inflammation and chemotaxis. A proteome comparative analysis revealed the overexpression of LbrPGF2S (prostaglandin f2-alpha synthase) and HSP70 in both LbrC isolates. Overexpression of LbrPGF2S in LbrC and LbrM promastigotes led to an increase in infected macrophages and the number of amastigotes per cell at 24-48 h post-infection (p.i.). CONCLUSIONS/SIGNIFICANCE: Despite sharing high similarity at the genome structure and ploidy levels, the parasites exhibited divergent expressed genomes. The proteome and metabolome results indicated differential profiles between the cutaneous and mucosal isolates, primarily related to inflammation and chemotaxis. BALB/c infection revealed that the cutaneous isolates were more virulent than the mucosal parasites. Furthermore, our data suggest that the LbrPGF2S protein is a candidate to contribute to parasite virulence profiles in the mammalian host.

Assuntos

Leishmania braziliensis/genética , Leishmania braziliensis/isolamento & purificação , Leishmaniose Mucocutânea/microbiologia , Metaboloma , Mucosa/microbiologia , Proteoma , Pele/microbiologia , Animais , Brasil , Modelos Animais de Doenças , Perfilação da Expressão Gênica , Humanos , Leishmaniose Mucocutânea/patologia , Camundongos Endogâmicos BALB C , Mucosa/patologia , Pele/patologia

RESUMO

Protein arginine methylation is a widely conserved post-translational modification performed by arginine methyltransferases (PRMTs). However, its functional role in parasitic protozoa is still under-explored. The Leishmania major genome encodes five PRMT homologs, including PRMT7. Here we show that LmjPRMT7 expression and arginine monomethylation are tightly regulated in a lifecycle stage-dependent manner. LmjPRMT7 levels are higher during the early promastigote logarithmic phase, negligible at stationary and late-stationary phases and rise once more post-differentiation to intracellular amastigotes. Immunofluorescence and co-immunoprecipitation studies demonstrate that LmjPRMT7 is a cytosolic protein associated with several RNA-binding proteins (RBPs) from which Alba20 is monomethylated only in LmjPRMT7-expressing promastigote stages. In addition, Alba20 protein levels are significantly altered in stationary promastigotes of the LmjPRMT7 knockout mutant. Considering RBPs are well-known mammalian PRMT substrates, our data suggest that arginine methylation via LmjPRMT7 may modulate RBP function during Leishmania spp. lifecycle progression. Importantly, genomic deletion of the LmjPRMT7 gene leads to an increase in parasite infectivity both in vitro and in vivo, while lesion progression is significantly reduced in LmjPRMT7-overexpressing parasites. This study is the first to describe a role of Leishmania protein arginine methylation in host-parasite interactions.