Luca Liberale1, Maria Bertolotto2, Federico Carbone2, Paola Contini3, Patricia Wüst4, Giovanni Spinella5, Bianca Pane5, Domenico Palombo5, Aldo Bonaventura2, Aldo Pende6, François Mach7, Franco Dallegri8, Giovanni G Camici4, Fabrizio Montecucco9. 1. Center for Molecular Cardiology, University of Zürich, Wagistrasse 12, 8952 Schlieren, Switzerland; First Clinic of Internal Medicine, Department of Internal Medicine, University of Genoa, 6 Viale Benedetto XV, 16132 Genoa, Italy. 2. First Clinic of Internal Medicine, Department of Internal Medicine, University of Genoa, 6 Viale Benedetto XV, 16132 Genoa, Italy. 3. Clinical Immunology, Department of Internal Medicine, University of Genoa, 6 viale Benedetto XV, 16132 Genoa, Italy. 4. Center for Molecular Cardiology, University of Zürich, Wagistrasse 12, 8952 Schlieren, Switzerland. 5. Vascular and Endovascular Surgery Unit, Department of Surgery, Ospedale Policlinico San Martino, 10 Largo Benzi, 16132 Genoa, Italy. 6. Clinic of Emergency Medicine, Department of Emergency Medicine, University of Genoa and Ospedale Policlinico San Martino, 10 Largo Rosanna Benzi, 16132 Genoa, Italy. 7. Division of Cardiology, Department of Medical Specialties, Geneva University Hospitals, 4 rue Gabrielle-Perret-Gentil, 1211 Geneva, Switzerland. 8. First Clinic of Internal Medicine, Department of Internal Medicine, University of Genoa, 6 Viale Benedetto XV, 16132 Genoa, Italy; Ospedale Policlinico San Martino, 10 Largo Benzi, 16132 Genoa, Italy. 9. First Clinic of Internal Medicine, Department of Internal Medicine, University of Genoa, 6 Viale Benedetto XV, 16132 Genoa, Italy; Ospedale Policlinico San Martino, 10 Largo Benzi, 16132 Genoa, Italy; Centre of Excellence for Biomedical Research (CEBR), University of Genoa, 9 Viale Benedetto XV, 16132 Genoa, Italy. Electronic address: fabrizio.montecucco@unige.it.
Abstract
BACKGROUND: Neutrophil functions have been shown to be modulated by adipocytokines during atherogenesis. The immuno-regulatory role of resistin on neutrophil-mediated activities in atherosclerotic patients remains elusive. Here, we aimed at exploring the association between serum levels of resistin and neutrophil products either in the systemic circulation or within plaques in a cohort of patients with severe carotid plaque stenosis undergoing endarterectomy. In addition, we assessed the effects of resistin on neutrophil pro-atherosclerotic functions in vitro. METHODS: Inflammatory biomarkers, neutrophil products and resistin levels were assessed in patients' sera and carotid plaques by ELISA and immunohistochemistry analysis. In vitro, human primary neutrophils isolated from healthy donors were assessed on different substrate cultures for: degranulation (by ELISA), migration (by microchemotaxis Boyden chamber), F-actin polymerization (by fluorescent assay), integrin and chemokine receptor expression (by flow cytometry) and apoptosis (by both morphologic analysis and flow cytometry). RESULTS: Serum resistin was positively correlated with serum levels of neutrophil granule products, but inversely with intraplaque neutrophil and MMP-9 contents. In vitro, resistin was detected in supernatants of degranulating neutrophils and positively correlated with other granule products. Although resistin did not affect neutrophil degranulation, apoptosis and integrin or chemokine receptor expression, pre-incubation with human recombinant resistin abrogated CXCL8-induced neutrophil migration and F-actin polymerization by inhibiting ERK2 phosphorylation. CONCLUSION: Resistin can be released by degranulating neutrophils and blunts neutrophil plaque infiltration by modulating their migration towards known atherosclerotic mediators. These results suggest a potential immunoregulatory role of resistin in inhibiting neutrophil-mediated atherosclerotic activities.
BACKGROUND: Neutrophil functions have been shown to be modulated by adipocytokines during atherogenesis. The immuno-regulatory role of resistin on neutrophil-mediated activities in atheroscleroticpatients remains elusive. Here, we aimed at exploring the association between serum levels of resistin and neutrophil products either in the systemic circulation or within plaques in a cohort of patients with severe carotid plaque stenosis undergoing endarterectomy. In addition, we assessed the effects of resistin on neutrophil pro-atherosclerotic functions in vitro. METHODS: Inflammatory biomarkers, neutrophil products and resistin levels were assessed in patients' sera and carotid plaques by ELISA and immunohistochemistry analysis. In vitro, human primary neutrophils isolated from healthy donors were assessed on different substrate cultures for: degranulation (by ELISA), migration (by microchemotaxis Boyden chamber), F-actin polymerization (by fluorescent assay), integrin and chemokine receptor expression (by flow cytometry) and apoptosis (by both morphologic analysis and flow cytometry). RESULTS: Serum resistin was positively correlated with serum levels of neutrophil granule products, but inversely with intraplaque neutrophil and MMP-9 contents. In vitro, resistin was detected in supernatants of degranulating neutrophils and positively correlated with other granule products. Although resistin did not affect neutrophil degranulation, apoptosis and integrin or chemokine receptor expression, pre-incubation with human recombinant resistin abrogated CXCL8-induced neutrophil migration and F-actin polymerization by inhibiting ERK2 phosphorylation. CONCLUSION:Resistin can be released by degranulating neutrophils and blunts neutrophil plaque infiltration by modulating their migration towards known atherosclerotic mediators. These results suggest a potential immunoregulatory role of resistin in inhibiting neutrophil-mediated atherosclerotic activities.