title: Targeting macrophage necroptosis for therapeutic and diagnostic interventions in atherosclerosis.
abstract: Atherosclerosis results from maladaptive inflammation driven primarily by macrophages, whose recruitment and proliferation drive plaque progression. In advanced plaques, macrophage death contributes centrally to the formation of plaque necrosis, which underlies the instability that promotes plaque rupture and myocardial infarction. Hence, targeting macrophage cell death pathways may offer promise for the stabilization of vulnerable plaques. Necroptosis is a recently discovered pathway of programmed cell necrosis regulated by RIP3 and MLKL kinases that, in contrast to apoptosis, induces a proinflammatory state. We show herein that necroptotic cell death is activated in human advanced atherosclerotic plaques and can be targeted in experimental atherosclerosis for both therapeutic and diagnostic interventions. In humans with unstable carotid atherosclerosis, expression of RIP3 and MLKL is increased, and MLKL phosphorylation, a key step in the commitment to necroptosis, is detected in advanced atheromas. Investigation of the molecular mechanisms underlying necroptosis showed that atherogenic forms of low-density lipoprotein increase RIP3 and MLKL transcription and phosphorylation-two critical steps in the execution of necroptosis. Using a radiotracer developed with the necroptosis inhibitor necrostatin-1 (Nec-1), we show that (123)I-Nec-1 localizes specifically to atherosclerotic plaques in Apoe (-/-) mice, and its uptake is tightly correlated to lesion areas by ex vivo nuclear imaging. Furthermore, treatment of Apoe (-/-) mice with established atherosclerosis with Nec-1 reduced lesion size and markers of plaque instability, including necrotic core formation. Collectively, our findings offer molecular insight into the mechanisms of macrophage cell death that drive necrotic core formation in atherosclerosis and suggest that this pathway can be used as both a diagnostic and therapeutic tool for the treatment of unstable atherosclerosis.
authors.affiliation: University of Ottawa Heart Institute, Ottawa, Ontario K1Y4W7, Canada.
authors.forename: Denuja
authors.identifier: 0000-0002-4789-8634
authors.initials: D
authors.lastname: Karunakaran
authors.affiliation: University of Ottawa Heart Institute, Ottawa, Ontario K1Y4W7, Canada.
authors.forename: Michele
authors.initials: M
authors.lastname: Geoffrion
authors.affiliation: University of Ottawa Heart Institute, Ottawa, Ontario K1Y4W7, Canada.; Canadian Molecular Imaging Centre of Excellence, University of Ottawa Heart Institute, Ottawa, Ontario K1Y4W7, Canada.
authors.forename: Lihui
authors.initials: L
authors.lastname: Wei
authors.affiliation: University of Ottawa Heart Institute, Ottawa, Ontario K1Y4W7, Canada.; Canadian Molecular Imaging Centre of Excellence, University of Ottawa Heart Institute, Ottawa, Ontario K1Y4W7, Canada.
authors.forename: Wei
authors.identifier: 0000-0002-1270-6495
authors.initials: W
authors.lastname: Gan
authors.affiliation: University of Ottawa Heart Institute, Ottawa, Ontario K1Y4W7, Canada.
authors.forename: Laura
authors.initials: L
authors.lastname: Richards
authors.affiliation: University of Ottawa Heart Institute, Ottawa, Ontario K1Y4W7, Canada.
authors.forename: Prakriti
authors.initials: P
authors.lastname: Shangari
authors.affiliation: University of Ottawa Heart Institute, Ottawa, Ontario K1Y4W7, Canada.
authors.forename: Ella M
authors.initials: EM
authors.lastname: DeKemp
authors.affiliation: University of Ottawa Heart Institute, Ottawa, Ontario K1Y4W7, Canada.
authors.forename: Rachelle A
authors.initials: RA
authors.lastname: Beanlands
authors.affiliation: Department of Molecular Medicine and Surgery, Karolinska Institute, Stockholm 171 76, Sweden.
authors.forename: Ljubica
authors.initials: L
authors.lastname: Perisic
authors.affiliation: Department of Medicine, Karolinska Institute, Stockholm 171 76, Sweden.
authors.forename: Lars
authors.identifier: 0000-0001-5228-2634
authors.initials: L
authors.lastname: Maegdefessel
authors.affiliation: Department of Molecular Medicine and Surgery, Karolinska Institute, Stockholm 171 76, Sweden.
authors.forename: Ulf
authors.initials: U
authors.lastname: Hedin
authors.affiliation: Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario K1H8L1, Canada.
authors.forename: Subash
authors.initials: S
authors.lastname: Sad
authors.affiliation: CVPath Institute Inc., Gaithersburg, MD 20878, USA.
authors.forename: Liang
authors.identifier: 0000-0002-1376-6772
authors.initials: L
authors.lastname: Guo
authors.affiliation: CVPath Institute Inc., Gaithersburg, MD 20878, USA.
authors.forename: Frank D
authors.identifier: 0000-0002-6007-2044
authors.initials: FD
authors.lastname: Kolodgie
authors.affiliation: CVPath Institute Inc., Gaithersburg, MD 20878, USA.
authors.forename: Renu
authors.initials: R
authors.lastname: Virmani
authors.affiliation: University of Ottawa Heart Institute, Ottawa, Ontario K1Y4W7, Canada.; Canadian Molecular Imaging Centre of Excellence, University of Ottawa Heart Institute, Ottawa, Ontario K1Y4W7, Canada.
authors.forename: Terrence
authors.identifier: 0000-0002-0686-5449
authors.initials: T
authors.lastname: Ruddy
authors.affiliation: University of Ottawa Heart Institute, Ottawa, Ontario K1Y4W7, Canada.; Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario K1H8L1, Canada.
authors.forename: Katey J
authors.initials: KJ
authors.lastname: Rayner
mesh_terms: D000590:Amino Acid Chloromethyl Ketones / Q000633:toxicity; D000818:Animals; D001057:Apolipoproteins E / Q000172:deficiency / Q000235:genetics; D017209:Apoptosis / Q000187:drug effects; D050197:Atherosclerosis / Q000175:diagnosis* / Q000628:therapy* / Q000662:veterinary; D001854:Bone Marrow Cells / Q000166:cytology; D002478:Cells, Cultured; D002784:Cholesterol / Q000097:blood; D003331:Coronary Vessels / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D006801:Humans; D007093:Imidazoles / Q000737:chemistry / Q000627:therapeutic use; D007211:Indoles / Q000737:chemistry / Q000627:therapeutic use; D053583:Interleukin-1beta / Q000097:blood; D008077:Lipoproteins, LDL / Q000633:toxicity; D008264:Macrophages / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009336:Necrosis / Q000628:therapy; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D053422:Receptor-Interacting Protein Serine-Threonine Kinases / Q000172:deficiency / Q000235:genetics / Q000378:metabolism
chemical_list: D000590:Amino Acid Chloromethyl Ketones; D001057:Apolipoproteins E; D007093:Imidazoles; D007211:Indoles; D053583:Interleukin-1beta; D008077:Lipoproteins, LDL; D017382:Reactive Oxygen Species; C484771:benzyloxycarbonyl-valyl-aspartic acid fluoromethyl ketone; C507699:necrostatin-1; C099252:oxidized low density lipoprotein; D002784:Cholesterol; C570693:MLKL protein, human; D011494:Protein Kinases; C119705:RIPK3 protein, human; D053422:Receptor-Interacting Protein Serine-Threonine Kinases
keywords: Atherosclerosis; cardiovascular disorders; necrosis; target cells; vascular diseases