Bone marrow granulocytes downregulate IL-1ß and TNF production and the microbicidal activity of inflammatory macrophages.

Macrophages play critical roles in inflammation and defense against pathogens, as well as in the return to tissue homeostasis. Macrophage subpopulations displaying antagonistic phenotypes are generally classified as proinflammatory M1, implicated in antipathogen and antitumoral activities, or as anti-inflammatory M2, associated with tissue repair. Granulocytic and monocytic myeloid-derived suppressor cells recruited from the bone marrow to tissues and phagocytosis of apoptotic neutrophils can attenuate macrophage microbicidal activity. Here, we showed that bone marrow neutrophils, but not thioglycollate-recruited neutrophils, directly suppress the responses of macrophages that were previously committed to an inflammatory phenotype. Cocultures of inflammatory macrophages with bone marrow CD11b+Ly6Ghi granulocytes led to reduced release of IL-1ß, TNF-α, and IL-6 by macrophages after lipopolysaccharide stimulation. The suppressive activity was unrelated to granulocyte apoptosis or to secreted factors and required cell-to-cell contact. The suppressive effect was paralleled by reduction in the nuclear levels of the NF-κB p65 subunit, but not of the p50 subunit. Furthermore, bone marrow granulocytes decreased the phagocytic activity of macrophages and their capacity to kill intracellular Escherichia coli. Taken together, these results show that bone marrow granulocytes can function as suppressors of the proinflammatory activity and microbial-killing responses of macrophages.

Tissue factor mediates microvesicles shedding from MDA-MB-231 breast cancer cells.

Extracellular vesicles, such as microvesicles (MVs), were identified as important players in tumor progression and acquisition of an aggressive phenotype. Tissue factor (TF) is a transmembrane protein that initiates the blood coagulation cascade. In tumor cells, TF has been associated with aggressiveness and cancer progression. Previous studies demonstrate that TF is incorporated into MVs secreted by tumor cells; however, it is unknown whether TF is actively involved in the release of MVs. Here, we investigated the influence of TF expression on the release of MVs. TF silencing was achieved through CRISPR/Cas9 approaches in the human breast cancer cell line, MDA-MB-231. TF knockout in MDA-MB-231 cells efficiently reduced TF-dependent signaling and procoagulant activity. Remarkably, silencing of TF caused a significant decrease in the number of MVs released by MDA-MB-231 cells. We also observed an increase in actin-positive membrane projections in TF knockout cells and a reduction in RhoA expression when compared to TF-expressing cells. Treatment of MDA-MB-231 cells with the RhoA-ROCK signaling pathway inhibitor, fasudil, significantly reduced the release of MVs. Taken together, our results suggest a novel and relevant role for TF in tumor biology by playing an active role in the MVs secretion.

Amphotericin-B-loaded polymer-functionalized reduced graphene oxides for Leishmania amazonensis chemo-photothermal therapy.

Two platforms based on reduced graphene oxide (rGO) functionalized with Pluronic® P123 (rGO-P123) and polyethyleneimine - PEI (rGO-PEI) polymers and loaded with amphotericin B (AmB) were fabricated and tested against Leishmania amazonensis, which can cause cutaneous and diffuse cutaneous leishmaniasis. The materials rGO-P123 and rGO-PEI were efficiently loaded with AmB - a polyene antibiotic - which resulted in rGO-P123-AmB (0.078 mg per mg of material) and rGO-PEI-AmB (0.086 mg per mg of material). Under near-infrared (NIR) light irradiation, the amount of AmB released from rGO-PEI-AmB at pH 5.0 and 7.4 doubled in comparison to AmB released in the absence of NIR light under identical conditions. It was accompanied by a photothermal effect. Otherwise, rGO-P123-AmB did not show a significant change in AmB released in the presence and absence of NIR light. Cytotoxicity studies in mammalian host macrophages revealed that rGO-PEI and rGO-PEI-AmB were nontoxic to the host cells, whereas rGO-123 and rGO-P123-AmB were very toxic, particularly the latter. Therefore, only rGO-PEI and rGO-PEI-AmB were tested against L. amazonensis promastigotes in the presence and absence of NIR light. In vitro antiproliferative effects revealed that rGO-PEI-AmB showed a more pronounced activity against the parasite than rGO-PEI, which was improved under NIR light irradiation. Scanning-transmission electron microscopy of L. amazonensis promastigotes after incubation with rGO-PEI or rGO-PEI-AmB suggested autophagic and necrotic cell death. Thus, the facile synthesis, high AmB loading capacity and good photothermal effect make the rGO-PEI-AmB platform a promising candidate for the topical treatment of cutaneous leishmaniasis.

Fabrication data of two light-responsive systems to release an antileishmanial drug activated by infrared photothermal heating.

The data provided in this study are related to the fabrication of two light-responsive systems based on reduced graphene oxide (rGO) functionalized with the polymers Pluronic P123 (P123), rGO-P123, and polyethyleneimine (PEI), rGO-PEI, and loaded with amphotericin B (AmB), an antileishmanial drug. Here are described the experimental design to obtain the systems and characterization methods, such as Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR), Raman Spectroscopy, Powder X-Ray Diffraction, Transmission Electron Microscopy, Scanning Electron Microscopy and Thermogravimetric Analyses. Also, AmB spectroscopy studies are described. The materials rGO-P123 and rGO-PEI were loaded with AmB and the optimization of AmB and polymer fragments structures revealed several possible hydrogen bonds formed between the materials and the drug. The drug release was analyzed with and without Near-Infrared (NIR) light. In the studies conducted under NIR light irradiation for 10 min, an infrared lamp was disposed at 64 cm from the samples and an optical fiber thermometer was employed to measure the temperature variation. Cytotoxicity studies and antiproliferative assays against Leishmania amazonensis promastigotes were evaluated. The complete work data entitled Amphotericin-B-Loaded Polymer-Functionalized Reduced Graphene Oxides for Leishmania amazonensis Chemo-Photothermal Therapy have been published to Colloids and Surfaces B: Bionterfaces (https://doi.org/10.1016/j.colsurfb.2021.112169) [1].

Co-protoporphyrin IX and Sn-protoporphyrin IX inactivate Zika, Chikungunya and other arboviruses by targeting the viral envelope.

The global situation of diseases transmitted by arthropod-borne viruses such as Dengue (DENV), Yellow Fever (YFV), Chikungunya (CHIKV) and Zika (ZIKV) viruses is alarming and treatment of human infection by these arboviruses faces several challenges. The discovery of broad-spectrum antiviral molecules, able to inactivate different groups of viruses, is an interesting approach. The viral envelope is a common structure among arboviruses, being a potential target for antivirals. Porphyrins are amphipathic molecules able to interact with membranes and absorb light, being widely used in photodynamic therapy. Previously, we showed that heme, Co-protoporphyrin IX (CoPPIX) and Sn-protoporphyrin IX (SnPPIX) directly inactivate DENV and YFV infectious particles. Here we demonstrate that the antiviral activity of these porphyrins can be broadened to CHIKV, ZIKV, Mayaro virus, Sindbis virus and Vesicular Stomatitis virus. Porphyrin treatment causes viral envelope protein loss, affecting viral morphology, adsorption and entry into target cells. Also, light-stimulation enhanced the SnPPIX activity against all tested arboviruses. In summary, CoPPIX and SnPPIX were shown to be efficient broad-spectrum compounds to inactivate medically and veterinary important viruses.