M Estruch1, K Rajamäki2, J L Sanchez-Quesada3, P T Kovanen4, K Öörni5, S Benitez6, J Ordoñez-Llanos7. 1. Biomedical Research Institute Sant Pau (IIB-Sant Pau), Barcelona (Spain). C/Sant Antoni M. Claret, 167 08025 Barcelona, Spain. Electronic address: mestruch@santpau.cat. 2. Wihuri Research Institute (WRI). Haartmaninkatu, 8 FI-00290 Helsinki, Finland. Electronic address: kristiina.rajamaki@helsinki.fi. 3. Biomedical Research Institute Sant Pau (IIB-Sant Pau), Barcelona (Spain). C/Sant Antoni M. Claret, 167 08025 Barcelona, Spain; Molecular Biology and Biochemistry Department, Universitat Autònoma de Barcelona (UAB) Faculty of Medicine, Building M. Cerdanyola del Vallès, Spain. Electronic address: jsanchezq@santpau.cat. 4. Wihuri Research Institute (WRI). Haartmaninkatu, 8 FI-00290 Helsinki, Finland. Electronic address: petri.kovanen@wri.fi. 5. Wihuri Research Institute (WRI). Haartmaninkatu, 8 FI-00290 Helsinki, Finland. Electronic address: kati.oorni@wri.fi. 6. Biomedical Research Institute Sant Pau (IIB-Sant Pau), Barcelona (Spain). C/Sant Antoni M. Claret, 167 08025 Barcelona, Spain; Molecular Biology and Biochemistry Department, Universitat Autònoma de Barcelona (UAB) Faculty of Medicine, Building M. Cerdanyola del Vallès, Spain. Electronic address: sbenitez@santpau.cat. 7. Molecular Biology and Biochemistry Department, Universitat Autònoma de Barcelona (UAB) Faculty of Medicine, Building M. Cerdanyola del Vallès, Spain; Biochemistry Department. Hospital de la Santa Creu i Sant Pau Barcelona. C/Sant Quintí, 89 08026, Barcelona, Spain. Electronic address: jordonez@santpau.cat.
Abstract
BACKGROUND: Electronegative LDL (LDL(−)), a modified LDL fraction found in blood, induces the release of inflammatory mediators in endothelial cells and leukocytes. However, the inflammatory pathways activated by LDL(−) have not been fully defined. We aim to study whether LDL(−) induced release of the first-wave proinflammatory IL-1β in monocytes and monocyte-derived macrophages (MDM) and the mechanisms involved. METHODS: LDL(−) was isolated from total LDL by anion exchange chromatography. Monocytes and MDM were isolated from healthy donors and stimulated with LDL(+) and LDL(−) (100 mg apoB/L). RESULTS: In monocytes, LDL(−) promoted IL-1β release in a time-dependent manner, obtaining at 20 h-incubation the double of IL-1β release induced by LDL(−) than by native LDL. LDL(−)-induced IL-1β release involved activation of the CD14-TLR4 receptor complex. LDL(−) induced priming, the first step of IL-1β release, since it increased the transcription of pro-IL-1β (8-fold) and NLRP3 (3-fold) compared to native LDL. Several findings show that LDL(−) induced inflammasome activation, the second step necessary for IL-1β release. Preincubation of monocytes with K+ channel inhibitors decreased LDL(−)-induced IL-1β release. LDL(−) induced formation of the NLRP3-ASC complex. LDL(−) triggered 2-fold caspase-1 activation compared to native LDL and IL-1β release was strongly diminished in the presence of the caspase-1 inhibitor Z-YVAD. In MDM, LDL(−) promoted IL-1β release, which was also associated with caspase-1 activation. CONCLUSIONS: LDL(−) promotes release of biologically active IL-1β in monocytes and MDM by induction of the two steps involved: priming and NLRP3 inflammasome activation. SIGNIFICANCE: By IL-1β release, LDL(−) could regulate inflammation in atherosclerosis.
BACKGROUND: Electronegative LDL (LDL(−)), a modified LDL fraction found in blood, induces the release of inflammatory mediators in endothelial cells and leukocytes. However, the inflammatory pathways activated by LDL(−) have not been fully defined. We aim to study whether LDL(−) induced release of the first-wave proinflammatory IL-1β in monocytes and monocyte-derived macrophages (MDM) and the mechanisms involved. METHODS: LDL(−) was isolated from total LDL by anion exchange chromatography. Monocytes and MDM were isolated from healthy donors and stimulated with LDL(+) and LDL(−) (100 mg apoB/L). RESULTS: In monocytes, LDL(−) promoted IL-1β release in a time-dependent manner, obtaining at 20 h-incubation the double of IL-1β release induced by LDL(−) than by native LDL. LDL(−)-induced IL-1β release involved activation of the CD14-TLR4 receptor complex. LDL(−) induced priming, the first step of IL-1β release, since it increased the transcription of pro-IL-1β (8-fold) and NLRP3 (3-fold) compared to native LDL. Several findings show that LDL(−) induced inflammasome activation, the second step necessary for IL-1β release. Preincubation of monocytes with K+ channel inhibitors decreased LDL(−)-induced IL-1β release. LDL(−) induced formation of the NLRP3-ASC complex. LDL(−) triggered 2-fold caspase-1 activation compared to native LDL and IL-1β release was strongly diminished in the presence of the caspase-1 inhibitor Z-YVAD. In MDM, LDL(−) promoted IL-1β release, which was also associated with caspase-1 activation. CONCLUSIONS: LDL(−) promotes release of biologically active IL-1β in monocytes and MDM by induction of the two steps involved: priming and NLRP3 inflammasome activation. SIGNIFICANCE: By IL-1β release, LDL(−) could regulate inflammation in atherosclerosis.
Authors: Rafael Corrêa; Luís Felipe Fonseca Silva; Dalila Juliana Silva Ribeiro; Raquel das Neves Almeida; Igor de Oliveira Santos; Luís Henrique Corrêa; Lívia Pimentel de Sant'Ana; Leonardo Santos Assunção; Patrícia T Bozza; Kelly Grace Magalhães Journal: Front Immunol Date: 2020-01-09 Impact factor: 7.561
Authors: Gerd Hörl; Harald Froehlich; Ulrika Ferstl; Gerhard Ledinski; Josepha Binder; Gerhard Cvirn; Tatjana Stojakovic; Michael Trauner; Christoph Koidl; Erwin Tafeit; Karin Amrein; Hubert Scharnagl; Günther Jürgens; Seth Hallström Journal: PLoS One Date: 2016-02-03 Impact factor: 3.240