Dados do Trabalho

Título

Gasdermin-D activation in response to Leishmania infection induce a transient cell permeabilization to promote NLRP3 activation and host resistance to infection

Introdução

Leishmania is an obligate intracellular parasite that causes Leishmaniasis, a disease that affects millions of people worldwide. Leishmania evades immune response by inhibiting specific processes on parasite-containing immune cells, yet the NLRP3 inflammasome activation is key for disease outcome. The molecular mechanisms upstream of the inflammasome activation are still unclear and there is no evident host cell death in Leishmania-infected cells.

Objetivo(s)

We aim to investigated the participation of Gasdermin-D (GSDMD, a pore-forming effector protein associated with pyroptosis) during Leishmania infection in macrophages, in vivo and in human samples.

Material e Métodos

To achieve our goals we used flow cytometry, immunofluorescence, western blot, in vitro and in vivo infection of mice. All experiments were performed in triplicate. For in vivo experiments, we used at least 5 animals per group (in triplicate).
We also evaluated inflammasome activation in lesion biopsy of patients with cutaneous leishmaniasis (7 patients and 7 controls)

Resultados e Conclusão

In the in vitro experiments of LDH release and live cell visualization, we did not observe cell death by pyroptosis. We demonstrated by immunofluorescence and western blot that despite the absence of pyroptosis, GSDMD is active at the early stages of L. amazonensis infection in macrophages, allowing a transient cell permeabilization and potassium efflux, promoting NLRP3 inflammasome activation. Gsdmd–/– macrophages exhibit less ASC puncta formation and IL-1β production in response to infection, suggesting that the transient GSDMD-mediated permeabilization contributes for NLRP3 inflammasome activation. Mouse and macrophages deficient in GSDMD were highly susceptible to infection by several Leishmania species, including L. amazonensis, L. major, L. braziliensis and L. mexicana, confirming a key role of Gasdermin-D for inflammasome-mediated host resistance to infection. Finally, ASC/NLRP3 puncta and cleaved Gasdermin-D were present in skin biopsies of leishmaniasis patients, supporting the role of these molecules during active disease in humans. Altogether, our findings reveal that Leishmania infection triggers a transient activation of GSDMD and this molecule is critical for inflammasome activation and immunity in Leishmaniasis.

Palavras-chave

Leishmania, Inflammasome, Cell Death inhibition