Cytokines and microbicidal molecules regulated by IL-32 in THP-1-derived human macrophages infected with New World Leishmania species

Background: interleukin-32 (il-32) is expressed in lesions of patients with american tegumentary leishmaniasis (atl),but its precise role in the disease remains unknown. methodology/principal findings: in the present study,silencing and overexpression of il-32 was performed in thp-1-derived macrophages infected with leishmania (viannia) braziliensis or l. (leishmania) amazonensis to investigate the role of il-32 in infection. we report that leishmania species induces il-32γ,and show that intracellular il-32γ protein production is dependent on endogenous tnfα. silencing or overexpression of il-32 demonstrated that this cytokine is closely related to tnfα and il-8. remarkably,the infection index was augmented in the absence of il-32 and decreased in cells overexpressing this cytokine. mechanistically,these effects can be explained by nitric oxide cathelicidin and β-defensin 2 production regulated by il-32. conclusions: thus,endogenous il-32 is a crucial cytokine involved in the host defense against leishmania parasites. © 2017 dos santos et al.