Aim: To investigate the immune response of disseminated Ryzopus oryzae infection in immunocompetent mice. Methods: C57Bl/6, BALB/c and Swiss wild-type mice were intravenously infected with R. oryzae; the parameters of infection and immune response were determined. Transcriptional signature of Th17 immune response and infection in Il17ra-/- mice were also evaluated. Results: All mouse strains showed an initial spread of R. oryzae in the target tissues; however, after 30 days, C57Bl/6 and BALB/c mice showed an effective fungal clearance associated with specific production of IL-17 and IL-2. We also observed that 60% of Il17ra-/- mice succumbed to infection within 16 days. Conclusion: This study has established an immunocompetent model for disseminated mucormycosis and highlighted the role of IL-17 signaling in immunity against R. oryzae.

Abstract Paracoccidioidomycosis (PCM) is a systemic mycosis caused by the Paracoccidioides genus. Most of the patients with chronic form present sequelae, like pulmonary fibrosis, with no effective treatment, leading to impaired lung functions. In the present study, we aimed to investigate the antifibrotic activity of three compounds: pentoxifylline (PTX), azithromycin (AZT), and thalidomide (Thal) in a murine model of pulmonary PCM treated with itraconazole (ITC) or cotrimoxazole (CMX). BALB/c mice were inoculated with P. brasiliensis (Pb) by the intratracheal route and after 8 weeks, they were submitted to one of the following six treatments: PTX/ITC, PTX/CMX, AZT/ITC, AZT/CMX, Thal/ITC, and Thal/CMX. After 8 weeks of treatment, the lungs were collected for determination of fungal burden, production of OH-proline, deposition of reticulin fibers, and pulmonary concentrations of cytokines and growth factors. Pb-infected mice treated with PTX/ITC presented a reduction in the pulmonary concentrations of OH-proline, associated with lower concentrations of interleukin (IL)-6, IL-17, and transforming growth factor (TGF)-β1 and higher concentrations of IL-10 compared to the controls. The Pb-infected mice treated with AZT/CMX exhibited decreased pulmonary concentrations of OH-proline associated with lower levels of TGF-β1, and higher levels of IL-10 compared controls. The mice treated with ITC/Thal and CMX/Thal showed intense weight loss, increased deposition of reticulin fibers, high pulmonary concentrations of CCL3, IFN-γ and VEGF, and decreased concentrations of IL-6, IL-1β, IL-17, and TGF-β1. In conclusion, our findings reinforce the antifibrotic role of PTX only when associated with ITC, and AZT only when associated with CMX, but Thal did not show any action upon addition.

In this study, we aimed to evaluate the immunomodulatory effects of crude leaf extracts from Piper gaudichaudianum Kunth, P. arboreum Aub., P. umbellata L., P. fuligineum Kunth, and Peperomia obtusifolia A. Dietr. on an in vitro model of inflammatory response. The crude extracts were previously obtained by maceration of the leaves. The half-maximal inhibitory concentration was determined by the MTT assay using human peripheral blood mononuclear cells. Human monocytes were simultaneously challenged with each crude extract and lipopolysaccharide (LPS), the major component of the outer membrane of Gram-negative bacteria, to induce a strong inflammatory response. After 24 h of incubation, cell-free supernatants were used for evaluating the mediators involved in inflammation: H2O2, TNF-α, IL-8, IL-6, IL-1β, IL-10, IL-12, FGF-b, and TGF-β1. We also compared the results with the effects of ketoprofen, a well-known anti-inflammatory drug. The P. gaudichaudianum crude extract downmodulated the production of H2O2, IL-1β, IL-6, IL-8, and TGF-β1 by LPS-stimulated monocytes; P. arboreum, IL-1β, IL-6, IL-8, and TNF-α; P. umbellata and P. fuligineum, H2O2, IL-1β, IL-6, IL-8, IL-10, and TNF-α; and P. obtusifolia, H2O2, IL-6, IL-8, IL-10, and TNF-α. In general, the crude leaf extracts amplified the anti-inflammatory response when compared with ketoprofen, particularly reducing the production of IL-8, a mediator involved in neutrophil recruitment during tissue damage. Thus, the crude leaf extracts of P. gaudichaudianum, P. arboreum, P. umbellata, P. fuligineum, and Peperomia obtusifolia elicited an anti-inflammatory response against LPS-challenged monocytes. These findings show the anti-inflammatory properties of these crude leaf extracts and offer new perspectives for their use in the treatment of inflammatory diseases.

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We established three immunocompetent murine models of pulmonary mucormycosis to determine the involvement of the adaptive immune response in host resistance in pulmonary mucormycosis, a rapidly fatal disease caused mainly by Rhizopus spp. Immunocompetent BALB/c, C57BL/6, and Swiss mice were inoculated with R. oryzae via the intratracheal route. The inoculation resulted in an angioinvasive infection that spread to the brain, spleen, kidney, and liver. After 7 and 30 days of R. oryzae infection, C57BL/6 and BALB/c mice showed the lowest fungal load and highest production of IFN-γ and IL-2 by splenocytes, respectively. Swiss mice showed a higher fungal load 30 days p.i. and was associated with a weak development of the Th-1 profile. To confirm our findings, R. oryzae-infected IFN-γ-/- mice were evaluated after 60 days, where the mice still showed viable fungi in the lungs. This study showed, for the first time, that pulmonary mucormycosis in three widely used mouse strains resulted in an acute fungal dissemination without immunosuppression whose outcome varies according to the genetic background of the mice . We also identified the partial role of IFN-γ in the efficient elimination of R. oryzae during pulmonary infection.