title: Polyethylenimine-coated SPIONs trigger macrophage activation through TLR-4 signaling and ROS production and modulate podosome dynamics.
abstract: Polyethylenimine (PEI) is widely used as transfection agent in preclinical studies, both in vitro and in vivo. Due to their unique chemical and physical properties, SPIONs (superparamagnetic iron oxide nanoparticles) have been thoroughly studied as nanocarriers. PEI appears to activate different immune cells to an inflammatory response (M1/TH1), whereas the SPION-induced response seems to be context-dependent; the immunogenicity of the combination of these components has not been studied. Here we show that PEI-coated SPIONs (PMag) activate macrophages, as determined by measuring IL-12 secretion into culture medium and upregulation of several genes linked to the M1 phenotype. PMag-induced phosphorylation of p38 MAPK, p44/p42 MAPK and JNK, and upregulation of CD40, CD80, CD86 and I-A/I-E activation markers. PMag-induced macrophage activation depended partially on TLR4 (Toll-like receptor 4) and ROS (reactive oxygen species) signaling. Comparison of these responses with the LPS (lipopolysaccharide)-induced phenotype showed differences in gene expression profiling. PMag positively modulated podosome formation in murine macrophages, but hampered gelatin degradation by these cells. In conclusion, PMag induced an M1-like phenotype that was partially dependent on both TLR4 and ROS. These results show the adjuvant potential of PMag and suggest their use in vaccination schedules.
authors.affiliation: Department of Immunology and Oncology, Centro Nacional de Biotecnología (CNB)/CSIC, Darwin 3, Cantoblanco, 28049 Madrid, Spain; NanoBiomedicine Initiative, Centro Nacional de Biotecnología (CNB)/CSIC, Darwin 3, Cantoblanco, 28049 Madrid, Spain.
authors.forename: Vladimir
authors.initials: V
authors.lastname: Mulens-Arias
authors.affiliation: Department of Immunology and Oncology, Centro Nacional de Biotecnología (CNB)/CSIC, Darwin 3, Cantoblanco, 28049 Madrid, Spain; NanoBiomedicine Initiative, Centro Nacional de Biotecnología (CNB)/CSIC, Darwin 3, Cantoblanco, 28049 Madrid, Spain.
authors.forename: José M
authors.initials: JM
authors.lastname: Rojas
authors.affiliation: Department of Immunology and Oncology, Centro Nacional de Biotecnología (CNB)/CSIC, Darwin 3, Cantoblanco, 28049 Madrid, Spain; NanoBiomedicine Initiative, Centro Nacional de Biotecnología (CNB)/CSIC, Darwin 3, Cantoblanco, 28049 Madrid, Spain.
authors.forename: Sonia
authors.initials: S
authors.lastname: Pérez-Yagüe
authors.affiliation: Department of Biomaterials and Bioinspired Materials, Instituto de Ciencia de Materiales de Madrid (ICMM)/CSIC, Sor Juana Inés de la Cruz 3, Cantoblanco, 28049 Madrid, Spain.
authors.forename: María P
authors.initials: MP
authors.lastname: Morales
authors.affiliation: Department of Immunology and Oncology, Centro Nacional de Biotecnología (CNB)/CSIC, Darwin 3, Cantoblanco, 28049 Madrid, Spain; NanoBiomedicine Initiative, Centro Nacional de Biotecnología (CNB)/CSIC, Darwin 3, Cantoblanco, 28049 Madrid, Spain. Electronic address: dfbarber@cnb.csic.es.
authors.forename: Domingo F
authors.initials: DF
authors.lastname: Barber
mesh_terms: D000818:Animals; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005290:Ferric Compounds / Q000737:chemistry*; D006801:Humans; D007107:Immune System; D007249:Inflammation / Q000378:metabolism; D018664:Interleukin-12 / Q000378:metabolism; D008070:Lipopolysaccharides / Q000737:chemistry; D008262:Macrophage Activation / Q000187:drug effects*; D008264:Macrophages / Q000187:drug effects* / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D053758:Nanoparticles / Q000737:chemistry; D010641:Phenotype; D010766:Phosphorylation; D000069261:Podosomes / Q000378:metabolism*; D011094:Polyethyleneimine / Q000737:chemistry*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D015398:Signal Transduction; D051197:Toll-Like Receptor 4 / Q000378:metabolism*
chemical_list: D005290:Ferric Compounds; D008070:Lipopolysaccharides; D017382:Reactive Oxygen Species; C495345:TLR4 protein, human; C493487:Tlr4 protein, mouse; D051197:Toll-Like Receptor 4; D018664:Interleukin-12; C000499:ferric oxide; D011094:Polyethyleneimine
keywords: Degradation; Immune response; Macrophages; Nanoparticle