RT info:eu-repo/semantics/article T1 Stimulation of FcγR receptors induces monocyte chemoattractant protein-1 in the human monocytic cell line THP-1 by a mechanism involving IκB-α degradation and formation of p50/p65 NF-κB/Rel complexes A1 Alonso, Andrés A1 Bayón Prieto, Yolanda A1 Renedo, Marta A1 Sánchez Crespo, Mariano K1 Chemokines K1 Fc receptors K1 Monocytes K1 Macrophages K1 Quimiocinas K1 Monocitos K1 Macrófagos K1 24 Ciencias de la Vida AB THP-1 monocytic/macrophage cells were stimulated via their FcγR receptors with insolubleaggregates of human IgG and the production of the C–C chemokine monocyte chemoattractantprotein (MCP)-1 assayed. A dose- and time-dependent production of MCP-1 comparable to thatproduced by the most potent agonists could be detected in the culture medium by a sensitiveELISA assay. This was accompanied by a parallel activation of the transcription factor NF-κBasjudged from both the appearance ofκB-binding activity containing p50/p65 NF-κB/Rel complexes inthe nuclear extract and the disappearance of the NF-κB inhibitor IκB-αin the cell lysate. Incontrast, IκB-βand IκB-εexpression was not modified, thus pointing to the occurrence of aselective degradation of IκB-αunder those conditions. Attempts to modulate MCP-1 productionwith compounds that display inhibitory effects on the activation of NF-κB such as the proteasomeinhibitorN-acetyl-leucinyl-leucinyl-norleucinal, the antioxidant pyrrolidine dithiocarbamate and thesalicylate derivative 2-hydroxy-4-trifluoromethylbenzoic acid showed a parallel effect on bothMCP-1 production and NF-κB activation, thus pointing to the involvement ofκB-binding sites onthe transcriptional regulation of MCP-1 production. Our findings suggest the existence inmonocytic cells of a signaling mechanism initiated by cross-linking of low-affinity FcγR, most likelyof the FcγRII family since THP-1 cells do not express FcγRIII receptors, that involves activation ofNF-κB associated to the proteolytic degradation of IκB-αand leads to the transcriptional up-regulation of MCP-1 PB Oxford University Press SN 0953-8178 YR 2000 FD 2000 LK https://uvadoc.uva.es/handle/10324/47500 UL https://uvadoc.uva.es/handle/10324/47500 LA eng NO International Immunology, 2000, vol. 12, n. 4, p. 547-554 NO Producción Científica DS UVaDOC RD 29-may-2024