Dados do Trabalho

Título

Cytokine and miRNA Expression of THP-1 Cells Stimulated by Extracellular Vesicles Released by L. (L). infantum

Introdução

Visceral leishmaniasis is a chronic disease caused by Leishmania (Leishmania) infantum in Brazil. Despite the complexity of the host immune system, all Leishmania species possess various virulence factors that enable them to resist effector response of macrophages, triggering the pathogenesis of the infection. To ensure their invasion into host cells, parasites release effector molecules through the cell membrane, including extracellular vesicles (EV). These nanomolecules promote the modulation of cytokines and micro-RNAs (miRNAs), preparing cells for parasitic infection. Previous studies had shown that macrophages (THP-1 cells) and from mice support these findings, indicating that EVs released by Leishmania (Leish-EVs) have the ability to modulate immune regulation and signaling.

Objetivo (s)

In this context, this study aimed to investigate the role of Leish-EVs released by L. (L). infantum in the regulation of humoral and cellular immune response in hosts with VL.

Material e Métodos

For the purpose of stimulating the cellular immune response, THP-1 cells were incubated for 24 hours with Leish-EVs. For each experiment, a normal control was included, which consisted of the same cell concentration but without treatment. The reactions for cytokine and miRNA expression were assessed using real-time PCR.

Resultados e Conclusão

The cytokines IL-10 and IL-12 were expressed at a ratio of 7 and 4 times higher, respectively. Additionally, the cytokines TGF, TNF-α, and IL-6 were also expressed, albeit at a lower intensity. The expression values were 1.51, 1.20, and 1.11, respectively, higher than the expression of the control. The IFN-γ was not detected in any of the samples. The expression of miR-21-5p and miR-146a-5p was found to be positive in THP-1 cells treated with Leish-EVs, with an average relative quantification (RQ) of 6.97 and 2.73, respectively. These values indicated an expression level approximately 7 and 3 times higher than that of untreated cells (control). miR-125b-5p and miR-144-3p were slightly expressed, with RQ values of 1.40 and 0.42, respectively. In summary, Leish-EVs-treated macrophages exhibited high expression of miR-21-5p and miR-146a-5p, leading to IL-10 dysregulation. These results suggest that the elevated expression of these miRNA species may be attributed to the presence of Leish-EVs. Consequently, this molecular pathway could contribute to immunosuppression and IL-10 dysregulation, potentially exacerbating immunopathology in infected hosts.

Palavras Chave

Leishmania (Leishmania) infantum; THP-1 cells; cytokines; extracellular vesicles; miRNAs.