Silva JC, Rodrigues NC, Thompson-Souza GA, Muniz VS, Neves JS, Figueiredo RT. Mac-1 triggers neutrophil DNA extracellular trap formation to Aspergillus fumigatus independently of PAD4 histone citrullination. J Leukoc Biol. 2020 Jan;107(1):69-83.

DOI: https://doi.org/10.1002/jlb.4a0119-009rr

///

Aspergillus fumigatus (A. fumigatus) is an environmental fungus and a human pathogen. Neutrophils are critical effector cells during the fungal infections, and neutropenia is a risk factor for the development of pulmonary aspergillosis. Neutrophil extracellular traps (NETs) are released by neutrophils in response to A. fumigatus and inhibit the conidial germination. In this work, we observed that the receptors TLR2, TLR4, and Dectin-1 were dispensable for the A. fumigatus induced NET release. In contrast CD11b/CD18 was critical for the NET release in response to A. fumigatus conidia, and this required the CD11b I-domain-mediated recognition, whereas the blockade of the CD11b lectin domain did not affect the A. fumigatus induced NET release. A. fumigatus induced NET release relied on the activity of spleen tyrosine kinase (Syk), Src family kinase(s), and class IA PI3 kinase δ. Although A. fumigatus promoted histone citrullination, this process was dispensable for the NET release in response to A. fumigatus conidia. The A. fumigatus induced NET release required the reactive oxygen species generation by the NOX2 complex, in a downstream pathway requiring CD11b/CD18, Src kinase family activity, Syk and PI3K class IA δ. Our findings thus reveal the signaling pathways involved in the formation of NETs in response to A. fumigatus.

Linhares-Lacerda L, Temerozo JR, Ribeiro-Alves M, Azevedo EP, Mojoli A, Nascimento MTC, Silva-Oliveira G, Savino W, Foguel D, Bou-Habib DC, Saraiva EM. Neutrophil extracellular trap-enriched supernatants carry microRNAs able to modulate TNF-α production by macrophages. Sci Rep. 2020 Feb 17;10(1):2715.

DOI: https://doi.org/10.1038/s41598-020-59486-2

///

Neutrophil extracellular traps (NETs) emerge from the cell as a DNA scaffold associated with cytoplasmic and granular proteins, able to immobilize and kill pathogens. This association occurs following nuclear and granular membrane disintegration, allowing contact with the decondensed chromatin. Thus, it is reasonable to speculate that the DNA can also mix with miRNAs and carry them in NETs. Here, we report for the first time the presence of the miRNA carriers associated with NETs and miRNAs present in NET-enriched supernatants (NET-miRs), thus adding a novel class of molecules and new proteins that can be released and transported in the NET platform. We observed that the majority of NET-miRs were common to all four stimuli used (PMA, interleukin-8, amyloid fibrils and Leishmania), and that miRNA-142-3p carried by NETs down-modulates protein kinase Cα and regulates TNF-α production in macrophages upon NET interaction with these cells. Our findings unveil a novel role for NETs in the cell communication processes, allowing the conveyance of miRNA from neutrophils to neighboring cells.

Castro LL, Kitoko JZ, Xisto DG, Olsen PC, Guedes HLM, Morales MM, Lopes-Pacheco M, Cruz FF, Rocco PRM. Multiple doses of adipose tissue-derived mesenchymal stromal cells induce immunosuppression in experimental asthma. Stem Cells Transl Med. 2020 Feb;9(2):250-260.

DOI: https://doi.org/10.1002/sctm.19-0120

///

In experimental house dust mite (HDM)-induced allergic asthma, therapeutic administration of a single dose of adipose tissue-derived mesenchymal stromal cells (MSCs) ameliorates lung inflammation but is unable to reverse remodeling. We hypothesized that multiple doses of MSCs might exert better therapeutic effects by reducing lung inflammation and remodeling but might also result in immunosuppressive effects in experimental asthma. HDM was administered intranasally in C57BL/6 mice. After the last HDM challenge, mice received two or three doses of MSCs (105 cells per day) or saline intravenously. An additional cohort of mice received dexamethasone as a positive control for immunosuppression. Two and three doses of MSCs reduced lung inflammation, levels of interleukin (IL)-4, IL-13, and eotaxin; total leukocyte, CD4+ T-cell, and eosinophil counts in bronchoalveolar lavage fluid; and total leukocyte counts in bone marrow, spleen, and mediastinal lymph nodes. Two and three doses of MSCs also reduced collagen fiber content and transforming growth factor-β levels in lung tissue; however, the three-dose regimen was more effective, and reduced these parameters to control levels, while also decreasing α-actin content in lung tissue. Two and three doses of MSCs improved lung mechanics. Dexamethasone, two and three doses of MSCs similarly increased galectin levels, but only the three-dose regimen increased CD39 levels in the thymus. Dexamethasone and the three-dose, but not the two-dose regimen, also increased levels of programmed death receptor-1 and IL-10, while reducing CD4+CD8low cell percentage in the thymus. In conclusion, multiple doses of MSCs reduced lung inflammation and remodeling while causing immunosuppression in HDM-induced allergic asthma.

Marques da Fonseca L, Jacques da Silva LR, Santos Dos Reis J, Rodrigues da Costa Santos MA, de Sousa Chaves V, Monteiro da Costa K, Sa-Diniz JN, Freire de Lima CG, Morrot A, Nunes Franklim T, de Alcântara-Pinto DC, Freire de Lima ME, Previato JO, Mendonça-Previato L, Freire-de-Lima L. Piperine Inhibits TGF-β Signaling Pathways and Disrupts EMT-Related Events in Human Lung Adenocarcinoma Cells. Medicines (Basel). 2020 Apr 8;7(4):19.

DOI: https://doi.org/10.3390/medicines7040019

///

Piperine, an amide extracted from the Piper spices, exhibits strong anti-tumor properties. However, its effect on the epithelial–mesenchymal transition (EMT) process has never been investigated. Herein, we evaluate the toxic effect of piperine on lung adenocarcinoma (A549), breast adenocarcinoma (MDA-MB-231) and hepatocellular carcinoma (HepG2) cell lines, as well as its ability to inhibit EMT-related events induced by TGF-β1 treatment. Methods: The cell viability was investigated by MTT assay. Protein expression was evaluated by Western blot. Gene expression was monitored by real-time PCR. Zymography assay was employed to detect metalloproteinase (MMP) activity in conditioned media. Cell motility was assessed by the wound-healing and phagokinetic gold sol assays. Results: The results revealed that piperine was cytotoxic in concentrations over 100 µM, showing IC50 values for HepG2, MDA-MB-231 and A549 cell lines of 214, 238 and 198 µM, respectively. In order to investigate whether piperine would reverse the TGF-β1 induced-EMT, the A549 cell line was pretreated with sublethal concentrations of the natural amide followed by the addition of TGF-β1. Besides disrupting EMT-related events, piperine also inhibited both ERK 1/2 and SMAD 2 phosphorylation.