Itraconazole in combination with neutrophil depletion reduces the expression of genes related to pulmonary fibrosis in an experimental model of paracoccidioidomycosis.

Abstract

Itraconazole (ITC) is the drug of choice for treating paracoccidioidomycosis (PCM); nonetheless, patients with the chronic form of this mycosis develop fibrosis, a residual pulmonary abnormality, even after treatment. Recently, we observed that the depletion of neutrophils with a specific monoclonal antibody (mAb-anti-Ly6G) during the chronic stages of PCM was associated with a decrease in the fungal burden, the inflammatory response and a reduction of fibrosis. Herein, we aimed to evaluate the effect of ITC in combination with the mAb-anti-Ly6G in an experimental model of pulmonary PCM. BALB/c male mice were challenged with Paracoccidioides brasiliensis yeasts and treated with the mAb-anti-Ly6G and/or ITC at 4th week post-infection (p.i.) and then sacrificed at 12th week p.i. to assess neutrophil subpopulations, fungal load, collagen, expression of fibrosis- and pro-inflammatory-related genes and histopathology. We observed that combination of ITC/mAb-anti-Ly6G favored the control of infection and diminished the inflammatory response. Of note, such therapeutic strategy reduced the expression of IL-1β, IL-6, IL-17, IL-10, TNF-α, TGF-β1, TGF-β3, GATA-3, RORc, Ahr, MMP-1α, MMP-8 MMP-15, TIMP-1, and TIMP-2 genes in an additive manner compared to those mice treated with the mAb or ITC alone. Interestingly, ITC induced an increase of type-II neutrophils even in those mice treated with the mAb-anti-Ly6G. These results indicate that combination ITC/mAb-anti-Ly6G reduced the infection and pulmonary fibrosis through down-regulation of inflammatory and pro-fibrotic genes. Additionally, we confirmed the immunomodulatory properties of this antifungal in vivo. This work emphasizes the importance of exploring new potential combination treatments to treat fungal infections.