| Congresso Brasileiro de Microbiologia 2023 | Resumo: 476-1 | ||||
Resumo:Sporotrichosis is a neglected zoonosis caused by two pathogenic species of the genus Sporothrix. Brazil faces a hyperendemics of this mycosis caused by domestic feline transmission of Sporothrix brasiliensis. Since the mid-1990’s epizootic outbreak in Rio de Janeiro, countless human and animal cases were reported. Recently, zoonotic cases have been described in neighboring countries, such as Argentina and Chile and, unpredictably, outside Latin America in 2023 (Europe). In this worrying scenario, understanding the particularities of the cat-fungus interaction can shed light on crucial events to S. brasiliensis pathogenicity for its main host. Invertebrate models have proven to be a suitable biomodel to evaluate pathogens virulence, once the insect immune system displays high analogy to the mammalian innate response. The aim of this work was to investigate phenotypic and molecular aspects of Galleria mellonella immune response triggered by the infection with the dimorphic pathogen S. brasiliensis. To this end, survival curves were performed while daily evaluation of phenotypic parameters were conducted. Larvae in the final larval stage of development were selected, with uniform weight and coloration, without signs of melanization. Each larva was subcutaneously inoculated with 1x107 yeast/larva followed by incubation at 37°C, for ten days. Hemocyte and fungal load counting in the larvae hemolymph to establish defense cell density and Colony Forming Units (CFU) were evaluated. In addition, the expression of genes responsible for encoding antimicrobial peptides with antifungal potential such as Gallerimycin and Galiomycin were evaluated. In parallel, the expression of encoding stress management C7 Contig 15362 and C8 Contig 1910 genes, were also quantified. Days one (D1), five (D5) and eight (D8) were chosen for total RNA extraction from the larvae (Total RNA Isolation System Kit, PROMEGA, USA), with subsequent conversion into complementary DNA followed by RT- qPCR (7500 Fast Real-Time PCR System - Applied Biosystems, USA). Statistical significance was determined whenever p<0.05 were obtained. S. brasiliensis yeast load and the density of hemocytes increased proportionally, especially from the fifth day of infection, when the deleterious morphological changes of the larvae and mortality also began (p < 0.001; Kaplan-Meier). As for the molecular data, Gallerimycin, C7 Contig 15362 and C8 Contig 19101 genes were positively regulated (p < 0.05) at distinct moments of the infection process (p < 0.05). The AMP Gallerimycin gene provided the early highest expression (p<0.0001; Mann-Whitney test) while the Galiomycin showed no difference between along the survival curve or the experimental groups. Altogether, a time-dependent and alternately modulated profile in response to the deleterious events caused by S. brasiliensis was observed. These results suggest that the AMP Gallerimycin plays a relevant role in the insect’s response to S. brasiliensis infection, as previously described during Candida spp. infection. This work is unprecedented in evaluating the expression of defense-related genes of G. mellonella in response to a dimorphic fungus infection. In view of the high analogy between the innate response of G. mellonella to fungal infection and the therapeutic difficulties inherent in feline sporotrichosis, we intend to contribute to the future survey of potential alternative pathways related to this mycosis treatment and controlling. Palavras-chave: Antimicrobial Peptides, Gene Expression, Invertebrates, Sporotrichosis, Zoonosis Agência de fomento:Conselho Nacional de Desenvolvimento Científico e Tecnológico (PIBIC-CNPq-UFF, Brasil); Fundação de Amparo à Pesquisa no Estado do Rio de Janeiro, Brasil (FAPERJ E-26/211.502/2021), Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, Brasil. | |||||