title: Exploring New Inflammatory Biomarkers and Pathways during LPS-Induced M1 Polarization.
abstract: Identification of mediators triggering microglia activation and transference of noncoding microRNA (miRNA) into exosomes are critical to dissect the mechanisms underlying neurodegeneration. We used lipopolysaccharide- (LPS-) induced N9 microglia activation to explore new biomarkers/signaling pathways and to identify inflammatory miRNA (inflamma-miR) in cells and their derived exosomes. Upregulation of iNOS and MHC-II (M1-markers) and downregulation of arginase 1, FIZZ1 (M2-markers), and CX3CR1 (M0/M2 polarization) confirmed the switch of N9 LPS-treated cells into the M1 phenotype, as described for macrophages/microglia. Cells showed increased proliferation, activated TLR4/TLR2/NF-κB pathway, and enhanced phagocytosis, further corroborated by upregulated MFG-E8. We found NLRP3-inflammasome activation in these cells, probably accounting for the increased extracellular content of the cytokine HMGB1 and of the MMP-9 we have observed. We demonstrate for the first time that the inflamma-miR profiling (upregulated miR-155 and miR-146a plus downregulated miR-124) in M1 polarized N9 cells, noticed by others in activated macrophages/microglia, was replicated in their derived exosomes, likely regulating the inflammatory response of recipient cells and dissemination processes. Data show that LPS-treated N9 cells behave like M1 polarized microglia/macrophages, while providing new targets for drug discovery. In particular, the study yields novel insights into the exosomal circulating miRNA during neuroinflammation important for emerging therapeutic approaches targeting microglia activation.
authors.affiliation: Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Lisbon, Portugal.
authors.forename: Carolina
authors.identifier: 0000-0002-0639-4990
authors.initials: C
authors.lastname: Cunha
authors.affiliation: Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Lisbon, Portugal.
authors.forename: Cátia
authors.identifier: 0000-0001-8491-6822
authors.initials: C
authors.lastname: Gomes
authors.affiliation: Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Lisbon, Portugal; Department of Biochemistry and Human Biology, Faculty of Pharmacy, Universidade de Lisboa, Lisbon, Portugal.
authors.forename: Ana Rita
authors.identifier: 0000-0002-3418-3269
authors.initials: AR
authors.lastname: Vaz
authors.affiliation: Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Lisbon, Portugal; Department of Biochemistry and Human Biology, Faculty of Pharmacy, Universidade de Lisboa, Lisbon, Portugal.
authors.forename: Dora
authors.identifier: 0000-0002-3024-9777
authors.initials: D
authors.lastname: Brites
mesh_terms: D000818:Animals; D001119:Arginase / Q000378:metabolism*; D015415:Biomarkers / Q000378:metabolism; D016923:Cell Death; D049109:Cell Proliferation; D016207:Cytokines / Q000378:metabolism; D055354:Exosomes / Q000378:metabolism; D024243:HMGB1 Protein / Q000378:metabolism; D058847:Inflammasomes / Q000378:metabolism; D007249:Inflammation / Q000378:metabolism*; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism*; D008070:Lipopolysaccharides; D008264:Macrophages / Q000166:cytology* / Q000378:metabolism; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism; D051379:Mice; D035683:MicroRNAs / Q000378:metabolism; D017628:Microglia / Q000166:cytology* / Q000378:metabolism; D010587:Phagocytosis; D010641:Phenotype; D023062:Receptors, Interleukin-8A / Q000378:metabolism*
chemical_list: D015415:Biomarkers; D016207:Cytokines; D024243:HMGB1 Protein; C582808:HMGB1 protein, mouse; D058847:Inflammasomes; D036341:Intercellular Signaling Peptides and Proteins; D008070:Lipopolysaccharides; D035683:MicroRNAs; D023062:Receptors, Interleukin-8A; C413576:Retnla protein, mouse; D020780:Matrix Metalloproteinase 9; C501830:Mmp9 protein, mouse; C544448:Arg1 protein, mouse; D001119:Arginase