Inhibitor of apoptosis proteins, NAIP, cIAP1 and cIAP2 expression during macrophage differentiation and M1/M2 polarization Morón Calvente, Virginia Romero Pinedo, Salvador Toribio-Castelló, Sofía Plaza Díaz, Julio Abadía Molina, Ana Clara Rojas Barros, Domingo Isaac Beug, Shawn T. LaCasse, Eric C. MacKenzie, Alex Korneluk, Robert Abadía Molina, Francisco Monocytes and macrophages constitute the first line of defense of the immune system against external pathogens. Macrophages have a highly plastic phenotype depending on environmental conditions; the extremes of this phenotypic spectrum are a pro-inflammatory defensive role (M1 phenotype) and an anti-inflammatory tissue-repair one (M2 phenotype). The Inhibitor of Apoptosis (IAP) proteins have important roles in the regulation of several cellular processes, including innate and adaptive immunity. In this study we have analyzed the differential expression of the IAPs, NAIP, cIAP1 and cIAP2, during macrophage differentiation and polarization into M1 or M2. In polarized THP-1 cells and primary human macrophages, NAIP is abundantly expressed in M2 macrophages, while cIAP1 and cIAP2 show an inverse pattern of expression in polarized macrophages, with elevated expression levels of cIAP1 in M2 and cIAP2 preferentially expressed in M1. Interestingly, treatment with the IAP antagonist SMC-LCL161, induced the upregulation of NAIP in M2, the downregulation of cIAP1 in M1 and M2 and an induction of cIAP2 in M1 macrophages. 2018-05-24T12:02:23Z 2018-05-24T12:02:23Z 2018-03-08 journal article Morón-Calvente V, Romero-Pinedo S, Toribio-Castelló S, Plaza-Díaz J, Abadía-Molina AC, Rojas-Barros DI, et al. (2018) Inhibitor of apoptosis proteins, NAIP, cIAP1 and cIAP2 expression during macrophage differentiation and M1/M2 polarization. PLoS ONE 13(3): e019364 [http://hdl.handle.net/10481/51139] http://hdl.handle.net/10481/51139 doi.org/10.1371/journal.pone.0193643 eng http://creativecommons.org/licenses/by/3.0/es/ open access Atribución 3.0 España Public Library of Science (PLOS)