title: Cholesterol crystals enhance TLR2- and TLR4-mediated pro-inflammatory cytokine responses of monocytes to the proatherogenic oral bacterium Porphyromonas gingivalis.
abstract: Cholesterol deposits and pro-inflammatory cytokines play an essential role in the pathogenesis of atherosclerosis, a predominant cause of cardiovascular disease (CVD). Epidemiological evidence has linked periodontal disease (PD) with atherosclerotic CVD. Accordingly, viable periodontal pathogens, including Porphyromonas gingivalis, have been found in atherosclerotic plaques in humans and mice. We aimed to determine whether cholesterol crystals (CHCs) and oral bacteria synergize in the stimulation of human monocytes. Incubation of human monocytes with CHCs induced secretion of interleukin (IL)-1β, tumor necrosis factor (TNF)-α, IL-6, and IL-8. Moreover, CHCs markedly enhanced secretion of IL-1β by monocytes stimulated with the toll-like receptor (TLR) 4 agonist Escherichia coli lipopolysaccharide (LPS), and the TLR2 agonist Staphylococcus aureus lipoteichoic acid. Notably, CHCs also enhanced IL-1β secretion induced by P. gingivalis LPS and IL-1β secretion induced by whole P. gingivalis bacteria. This enhancement was abrogated by the NLRP3 inflammasome inhibitors Z-YVAD-FMK and glibenclamide. CHCs had no effect on cytokine production induced by P. gingivalis gingipains. Taken together, our findings support that CHCs, via stimulation of NLRP3 inflammasomes, act in synergy with the periodontal pathogen P. gingivalis to promote monocyte secretion of pro-atherogenic cytokines.
authors.affiliation: Institute for Inflammation Research, Center for Rheumatology and Spine Disease, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark.
authors.forename: Tania
authors.initials: T
authors.lastname: Køllgaard
authors.affiliation: Institute for Inflammation Research, Center for Rheumatology and Spine Disease, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark.
authors.forename: Christian
authors.initials: C
authors.lastname: Enevold
authors.affiliation: Institute for Inflammation Research, Center for Rheumatology and Spine Disease, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark.
authors.forename: Klaus
authors.initials: K
authors.lastname: Bendtzen
authors.affiliation: Department of Cardiology, Copenhagen University Hospital Gentofte, Copenhagen, Denmark.
authors.forename: Peter R
authors.initials: PR
authors.lastname: Hansen
authors.affiliation: Costerton Biofilm Center, Department of International Health, Immunology and Microbiology University of Copenhagen, Copenhagen, Denmark.
authors.forename: Michael
authors.initials: M
authors.lastname: Givskov
authors.affiliation: Section for Periodontology, Microbiology and Community Dentistry, Department of Odontology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Palle
authors.initials: P
authors.lastname: Holmstrup
authors.affiliation: Institute for Inflammation Research, Center for Rheumatology and Spine Disease, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark.|Section for Periodontology, Microbiology and Community Dentistry, Department of Odontology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Claus H
authors.initials: CH
authors.lastname: Nielsen
mesh_terms: D000818:Animals; D050197:Atherosclerosis / Q000150:complications / Q000378:metabolism* / Q000382:microbiology; D002784:Cholesterol / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D058847:Inflammasomes / Q000187:drug effects / Q000378:metabolism; D053583:Interleukin-1beta / Q000378:metabolism; D015850:Interleukin-6 / Q000378:metabolism; D016209:Interleukin-8 / Q000378:metabolism; D051379:Mice; D009000:Monocytes / Q000378:metabolism / Q000382:microbiology; D000071199:NLR Family, Pyrin Domain-Containing 3 Protein / Q000037:antagonists & inhibitors / Q000235:genetics*; D010510:Periodontal Diseases / Q000150:complications / Q000378:metabolism* / Q000382:microbiology; D058226:Plaque, Atherosclerotic / Q000378:metabolism / Q000382:microbiology; D016966:Porphyromonas gingivalis / Q000378:metabolism / Q000472:pathogenicity; D013211:Staphylococcus aureus / Q000737:chemistry / Q000472:pathogenicity; D051195:Toll-Like Receptor 2 / Q000008:administration & dosage / Q000819:agonists / Q000378:metabolism; D051197:Toll-Like Receptor 4 / Q000008:administration & dosage / Q000819:agonists / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: D058847:Inflammasomes; D053583:Interleukin-1beta; D015850:Interleukin-6; D016209:Interleukin-8; D000071199:NLR Family, Pyrin Domain-Containing 3 Protein; C495342:TLR2 protein, human; C495345:TLR4 protein, human; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D014409:Tumor Necrosis Factor-alpha; D002784:Cholesterol