Erythropoietin Exacerbates Inflammation and Increases the Mortality ofHistoplasma capsulatum-Infected Mice

Abstract

Erythropoietin (EPO) is a key hormone involved in red blood cell formation, but its effects on nonerythroid cells, such as macrophages, have not been described. Macrophages are key cells in controlling histoplasmosis, a fungal infection caused by Histoplasma capsulatum (Hc). Considering that little is known about EPO's role during fungal infections and its capacity to activate macrophages, in this study we investigated the impact of EPO pretreatment on the alveolar immune response during Hc infection. The consequence of EPO pretreatment on fungal infection was determined by evaluating animal survival, fungal burden, activation of bronchoalveolar macrophages, inflammatory mediator release, and lung inflammation. Pretreatment with EPO diminished mononuclear cell numbers, increased the recruitment of F4/80+/CD80+ and F4/80+/CD86+ cells to the bronchoalveolar space, induced higher production of IFN-γ, IL-6, MIP-1α, MCP-1, and LTB4, reduced PGE2 concentration, and did not affect fungal burden. As a consequence, we observed an increase in lung inflammation with extensive tissue damage that might account for augmented mouse mortality after infection. Our results demonstrate for the first time that EPO treatment has a deleterious impact on lung immune responses during fungal infection.

IL-22 Promotes IFN-γ-Mediated Immunity against Histoplasma capsulatum Infection

“…The H. capsulatum strain used in this study is a clinical isolate from a pulmonary histoplasmosis patient, obtained from Hospital das Clínicas de Ribeirão Preto (Ribeirão Preto, SP, Brazil) [9,11,12,14,15,40,41]. The strain was grown on brain heart infusion (BHI) agar (Difco-Detroit, MI, USA) supplemented with 5% of sterile defibrinated blood sheep (#1189 New Prov, Pinhais PR, Brazil) at 37 • C for 7-10 days.…”

“…Tissue was submitted to enzymatic digestion using Liberase (25 µg.mL −1 -Roche, Mannheim, Germany) and DNase (1 mg.mL −1 -Sigma Aldrich, St Louis, MO, USA) for 45 min at 37 • C, 150 rpm. Four serial dilutions were inoculated on blood agar and incubated at 37 • C for 3 weeks until yeast growth occurred [11,12,41].…”

“…Spleen: The spleen was removed, perforated using a syringe plunger in 1 mL of PBS 1×, plated on blood agar and incubated at 37 • C for 3 weeks until yeast growth occurred [11,12,41].…”

“…The lungs were homogenized using Turrax (IKA, Labortechnik, Staufen, Germany) with 1 mL of RPMI-I for each 100 mg of tissue. Then, the samples were centrifuged (753× g 10 min, 4 • C) and the supernatant removed and fractioned for lipid mediators or for cytokines quantification [41]. For lipid mediators, 500 µL of supernatants was mixed with methanol (v/v) and stored at -80 • C until lipid extraction.…”

Versatility of tandem mass spectrometry for focused analysis of oxylipids

“…[8] Different targeted LC-MS/MS methods have been developed in the last years for oxylipid identification. [9][10][11] This approach has been successfully applied in the determination of oxylipid profile in a variety of biological extracts including plasma, [12,13] blood, [14] urine, [15,16] cell supernatants, [17,18] and tissues, [19,20] thus assisting in the understanding of the role of these lipid mediators in health and disease conditions. [21][22][23] It is important to mention that a crucial step in the development of a targeted methodology is to pre-select the analytes of interest to be monitored in a given experiment.…”