UNIGE document Scientific Article
previous document  unige:77538  next document
add to browser collection
Title

Toll-like receptor 7 protects from atherosclerosis by constraining "inflammatory" macrophage activation

Authors
Salagianni, Maria
Galani, Ioanna E
Lundberg, Anna M
Davos, Constantinos H
Varela, Aimilia
Gavriil, Ariana
Lyytikäinen, Leo-Pekka
Lehtimäki, Terho
show hidden authors show all authors [1 - 18]
Published in Circulation. 2012, vol. 126, no. 8, p. 952-962
Abstract BACKGROUND:Toll-like receptors (TLRs) have long been considered to be major culprits in the development of atherosclerosis, contributing both to its progression and clinical complications. However, evidence for most TLRs beyond TLR2 and TLR4 is lacking. METHODS AND RESULTS:We used experimental mouse models, human atheroma cultures, and well-established human biobanks to investigate the role of TLR7 in atherosclerosis. We report the unexpected finding that TLR7, a receptor recognizing self-nucleic acid complexes, is protective in atherosclerosis. In Apoe(-/-) mice, functional inactivation of TLR7 resulted in accelerated lesion development, increased stenosis, and enhanced plaque vulnerability as revealed by Doppler ultrasound and/or histopathology. Mechanistically, TLR7 interfered with macrophage proinflammatory responses to TLR2 and TLR4 ligands, reduced monocyte chemoattractant protein-1 production, and prevented expansion of Ly6C(hi) inflammatory monocytes and accumulation of inflammatory M1 macrophages into developing atherosclerotic lesions. In human carotid endarterectomy specimens TLR7 levels were consistently associated with an M2 anti-inflammatory macrophage signature (interleukin [IL]-10, IL-1RA, CD163, scavenger and C-type lectin receptors) and collagen genes, whereas they were inversely related or unrelated to proinflammatory mediators (IL-12/IL-23, interferon beta, interferon gamma, CD40L) and platelet markers. Moreover, in human atheroma cultures, TLR7 activation selectively suppressed the production of key proatherogenic factors such as monocyte chemoattractant protein-1 and tumor necrosis factor without affecting IL-10. CONCLUSIONS:These findings provide evidence for a beneficial role of TLR7 in atherosclerosis by constraining inflammatory macrophage activation and cytokine production. This challenges the prevailing concept that all TLRs are pathogenic and supports the exploitation of the TLR7 pathway for therapy.
Keywords AnimalsAorta/immunology/pathologyApolipoproteins E/geneticsBiological Markers/metabolismCarotid Artery Diseases/immunology/pathologyCells, CulturedCytokines/immunologyDisease Models, AnimalFemaleHumansMacrophages, Peritoneal/immunology/pathologyMaleMembrane Glycoproteins/genetics/immunologyMiceMice, Inbred C57BLMice, KnockoutMonocytes/immunology/pathologyPlaque, Atherosclerotic/immunology/pathologyRNA, Messenger/metabolismToll-Like Receptor 7/genetics/immunology
Identifiers
PMID: 22787112
Full text
Article (Published version) (1.9 MB) - document accessible for UNIGE members only Limited access to UNIGE
Structures
Research group L'athérosclérose et ses complications cliniques (591)
Citation
(ISO format)
SALAGIANNI, Maria et al. Toll-like receptor 7 protects from atherosclerosis by constraining "inflammatory" macrophage activation. In: Circulation, 2012, vol. 126, n° 8, p. 952-962. https://archive-ouverte.unige.ch/unige:77538

109 hits

0 download

Update

Deposited on : 2015-11-23

Export document
Format :
Citation style :