MiR-548d-3p Alters Parasite Growth and Inflammation in Leishmania (Viannia) braziliensis Infection.

Maria Edileuza Felinto Brito,Paul Martin Kaye,Luiza Campos Reis,Lucile Maria Floeter-Winter,Eduardo Milton Ramos-Sanchez,Hiro Goto,Valéria Rêgo Alves Pereira,Dimitris Lagos,Ricardo Andrade Zampieri,Sandra Márcia Muxel,Marina De Assis Souza

doi:10.3389/fcimb.2021.687647

Abstract

American Tegumentary Leishmaniasis (ATL) is an endemic disease in Latin America, mainly caused in Brazil by Leishmania (Viannia) braziliensis. Clinical manifestations vary from mild, localized cutaneous leishmaniasis (CL) to aggressive mucosal disease. The host immune response strongly determines the outcome of infection and pattern of disease. However, the pathogenesis of ATL is not well understood, and host microRNAs (miRNAs) may have a role in this context. In the present study, miRNAs were quantified using qPCR arrays in human monocytic THP-1 cells infected in vitro with L. (V.) braziliensis promastigotes and in plasma from patients with ATL, focusing on inflammatory response-specific miRNAs. Patients with active or self-healed cutaneous leishmaniasis patients, with confirmed parasitological or immunological diagnosis, were compared with healthy controls. Computational target prediction of significantly-altered miRNAs from in vitro L. (V.) braziliensis-infected THP-1 cells revealed predicted targets involved in diverse pathways, including chemokine signaling, inflammatory, cellular proliferation, and tissue repair processes. In plasma, we observed distinct miRNA expression in patients with self-healed and active lesions compared with healthy controls. Some miRNAs dysregulated during THP-1 in vitro infection were also found in plasma from self-healed patients, including miR-548d-3p, which was upregulated in infected THP-1 cells and in plasma from self-healed patients. As miR-548d-3p was predicted to target the chemokine pathway and inflammation is a central to the pathogenesis of ATL, we evaluated the effect of transient transfection of a miR-548d-3p inhibitor on L. (V.) braziliensis infected-THP-1 cells. Inhibition of miR-548d-3p reduced parasite growth early after infection and increased production of MCP1/CCL2, RANTES/CCL5, and IP10/CXCL10. In plasma of self-healed patients, MCP1/CCL2, RANTES/CCL5, and IL-8/CXCL8 concentrations were significantly decreased and MIG/CXCL9 and IP-10/CXCL10 increased compared to patients with active disease. These data suggest that by modulating miRNAs, L. (V.) braziliensis may interfere with chemokine production and hence the inflammatory processes underpinning lesion resolution. Our data suggest miR-548d-3p could be further evaluated as a prognostic marker for ATL and/or as a host-directed therapeutic target.

Highlights

The leishmaniases are vector-borne diseases caused by protozoan parasites of the genus Leishmania
Macrophages exert a dual role in the pathogenesis of cutaneous leishmaniasis (CL), being both host cell and the main effector cell for parasite clearance (Tomiotto-Pellissier et al, 2018)
Leishmania employ strategies to evade the host immune response, including altering the miRNAs expression (Lemaire et al, 2013; Muxel et al, 2017; Muxel et al, 2018; Nunes et al, 2018; Fernandes et al, 2019; Paul et al, 2020). In this context, having access to L. braziliensisinfected active and self-healed CL patients, we searched for differentially expressed miRNAs in plasma and in parallel conducted an in vitro study using L. (V.) braziliensis infectedhuman monocyte-derived THP-1 cells

Summary

Introduction

The leishmaniases are vector-borne diseases caused by protozoan parasites of the genus Leishmania. Leishmania exists as promastigotes (elongated forms with an external flagellum) in the sandfly gut and as amastigotes (round or ovoid forms without an external flagellum) within mononuclear phagocytes of the vertebrate host. After promastigote inoculation in the skin by the vector, the parasites interact primarily with tissue humoral and cellular elements and the infection may progress to overt disease. Depending on the Leishmania species and host characteristics, the disease may manifest as visceral leishmaniasis, affecting organs, such as the liver and spleen, or tegumentary form, causing lesions in the skin and mucosa. Comparing active cutaneous and self-healed leishmaniasis patients constitutes a unique opportunity to explore pathogenic mechanisms of lesion development and control that are not fully elucidated

Methods

Results

Conclusion