scholarly journals Toll-Like Receptor 9-Mediated Inflammation Triggers Alveolar Bone Loss in Experimental Murine Periodontitis

2015 ◽  
Vol 83 (7) ◽  
pp. 2992-3002 ◽  
Author(s):  
Paul D. Kim ◽  
Xia Xia-Juan ◽  
Katie E. Crump ◽  
Toshiharu Abe ◽  
George Hajishengallis ◽  
...  
Keyword(s):  
Bone Loss ◽  
Cytokine Production ◽  
Alveolar Bone ◽  
Inflammatory Responses ◽  
Ex Vivo ◽  
Extracellular Dna ◽  
Toll Like Receptor ◽  
Content Type ◽  
Periodontal Inflammation

Chronic periodontitis is a local inflammatory disease induced by a dysbiotic microbiota and leading to destruction of the tooth-supporting structures. Microbial nucleic acids are abundantly present in the periodontium, derived through release after phagocytic uptake of microbes and/or from biofilm-associated extracellular DNA. Binding of microbial DNA to its cognate receptors, such as Toll-like receptor 9 (TLR9), can trigger inflammation. In this study, we utilized TLR9 knockout (TLR9−/−) mice and wild-type (WT) controls in a murine model ofPorphyromonas gingivalis-induced periodontitis and report the firstin vivoevidence that TLR9 signaling mediates the induction of periodontal bone loss.P. gingivalis-infected WT mice exhibited significantly increased bone loss compared to that in sham-infected WT mice orP. gingivalis-infected TLR9−/−mice, which were resistant to bone loss. Consistent with this, the expression levels of interleukin 6 (IL-6), tumor necrosis factor (TNF), and receptor-activator of nuclear factor kappa B ligand (RANKL) were significantly elevated in the gingival tissues of the infected WT mice but not in infected TLR9−/−mice compared to their levels in controls.Ex vivostudies using splenocytes and bone marrow-derived macrophages revealed significantly diminished cytokine production in TLR9−/−cells relative to the cytokine production in WT cells in response toP. gingivalis, thereby implicating TLR9 in inflammatory responses to this organism. Intriguingly, compared to the cytokine production in WT cells, TLR9−/−cells exhibited significantly decreased proinflammatory cytokine production upon challenge with lipopolysaccharide (LPS) (TLR4 agonist) or Pam3Cys (TLR2 agonist), suggesting possible cross talk between TLR9, TLR4, and TLR2. Collectively, our results provide the first proof-of-concept evidence implicating TLR9-triggered inflammation in periodontal disease pathogenesis, thereby identifying a new potential therapeutic target to control periodontal inflammation.

scholarly journals Interplay of Toll-Like Receptor 9, Myeloid Cells, and Deubiquitinase A20 in Periodontal Inflammation

2016 ◽  
Vol 85 (1) ◽  
Author(s):  
Katie E. Crump ◽  
Jennifer C. Oakley ◽  
Xia Xia-Juan ◽  
Theandra C. Madu ◽  
Swathi Devaki ◽  
...  
Keyword(s):  
Alveolar Bone ◽  
Ex Vivo ◽  
Negative Regulator ◽  
Gingival Tissue ◽  
Infection Model ◽  
Limiting Factor ◽  
Toll Like Receptor ◽  
Necrosis Factor Alpha ◽  
Content Type ◽  
Periodontal Inflammation

ABSTRACT Toll-like receptor 9 (TLR9)-deficient (TLR9−/−) mice are resistant to periodontitis, a disease characterized by a dysbiotic microbiota and deregulated immune response and resulting in tooth loss and various systemic conditions. However, the mechanisms and biological pathways by which TLR9 instigates periodontal inflammation are yet to be identified. In a ligature-induced model of periodontitis, we demonstrate that TLR9−/− mice exhibited significantly less alveolar bone loss than their wild-type (WT) counterparts. Consistent with the disease phenotype, gingival tissues showed significantly more inflammatory cell infiltration in the WT ligated but not in the TLR9−/− ligated mice compared to the unligated controls. The peritoneal infection model using Porphyromonas gingivalis, a keystone pathogen for periodontitis, revealed reduced neutrophils in TLR9−/− mice on day 1 postinfection compared to the levels in WT mice. Transcriptomics analyses showed increased expression of A20 (tumor necrosis factor alpha [TNF-α]-induced protein 3 [TNFAIP3]), an inhibitor of the NF-κB pathway and a negative regulator of TLR signaling, in ligated TLR9−/− mouse gingival tissues compared to its expression in the WT. Ex vivo, TLR9−/− bone marrow-derived macrophages produced more A20 than WT cells following P. gingivalis challenge. Clinically, A20 was modestly upregulated in human gingival tissue specimens from chronic periodontitis patients, further confirming the biological relevance of A20 in periodontal inflammation. We conclude that TLR9 modulates periodontal disease progression at both the cellular and molecular level and identify A20 as a novel downstream signaling molecule in the course of periodontal inflammation. Understanding the regulation of the TLR9 signaling pathway and the involvement of A20 as a limiting factor of inflammation will uncover alternative therapeutic targets to treat periodontitis and other chronic inflammatory diseases.

scholarly journals Serine Lipids of Porphyromonas gingivalis Are Human and Mouse Toll-Like Receptor 2 Ligands

2013 ◽  
Vol 81 (9) ◽  
pp. 3479-3489 ◽  
Author(s):  
Robert B. Clark ◽  
Jorge L. Cervantes ◽  
Mark W. Maciejewski ◽  
Vahid Farrokhi ◽  
Reza Nemati ◽  
...  
Keyword(s):  
Cell Activation ◽  
Inflammatory Responses ◽  
Periodontal Pathogen ◽  
Toll Like Receptor ◽  
Dendritic Cell Activation ◽  
Content Type ◽  
Hek Cells ◽  
Toll Like Receptor 2

ABSTRACTThe total cellular lipids ofPorphyromas gingivalis, a known periodontal pathogen, were previously shown to promote dendritic cell activation and inhibition of osteoblasts through engagement of Toll-like receptor 2 (TLR2). The purpose of the present investigation was to fractionate all lipids ofP. gingivalisand define which lipid classes account for the TLR2 engagement, based on bothin vitrohuman cell assays andin vivostudies in mice. Specific serine-containing lipids ofP. gingivalis, called lipid 654 and lipid 430, were identified in specific high-performance liquid chromatography fractions as the TLR2-activating lipids. The structures of these lipids were defined using tandem mass spectrometry and nuclear magnetic resonance methods.In vitro, both lipid 654 and lipid 430 activated TLR2-expressing HEK cells, and this activation was inhibited by anti-TLR2 antibody. In contrast, TLR4-expressing HEK cells failed to be activated by either lipid 654 or lipid 430. Wild-type (WT) or TLR2-deficient (TLR2−/−) mice were injected with either lipid 654 or lipid 430, and the effects on serum levels of the chemokine CCL2 were measured 4 h later. Administration of either lipid 654 or lipid 430 to WT mice resulted in a significant increase in serum CCL2 levels; in contrast, the administration of lipid 654 or lipid 430 to TLR2−/−mice resulted in no increase in serum CCL2. These results thus identify a new class of TLR2 ligands that are produced byP. gingivalisthat likely play a significant role in mediating inflammatory responses both at periodontal sites and, potentially, in other tissues where these lipids might accumulate.

scholarly journals Toll-Like Receptor 6 Plays an Important Role in Host Innate Resistance to Brucella abortus Infection in Mice

2013 ◽  
Vol 81 (5) ◽  
pp. 1654-1662 ◽  
Author(s):  
Leonardo A. de Almeida ◽  
Gilson C. Macedo ◽  
Fábio A. V. Marinho ◽  
Marco T. R. Gomes ◽  
Patrícia P. Corsetti ◽  
...  
Keyword(s):  
Immune Response ◽  
Dendritic Cells ◽  
Brucella Abortus ◽  
Proinflammatory Cytokine ◽  
Cytokine Production ◽  
Innate Immune ◽  
Proinflammatory Cytokine Production ◽  
Toll Like Receptor ◽  
Content Type

ABSTRACTBrucella abortusis recognized by several Toll-like receptor (TLR)-associated pathways triggering proinflammatory responses that affect both the nature and intensity of the immune response. Previously, we demonstrated thatB. abortus-mediated dendritic cell (DC) maturation and control of infection are dependent on the adaptor molecule MyD88. However, the involvement of all TLRs in response toB. abortusinfection is not completely understood. Therefore, we decided to evaluate the requirement for TLR6 in host resistance toB. abortus. Here, we demonstrated that TLR6 is an important component for triggering an innate immune response againstB. abortus. Anin vitroluciferase assay indicated that TLR6 cooperates with TLR2 to senseBrucellaand further activates NF-κB signaling. However,in vivoanalysis showed that TLR6, not TLR2, is required for the efficient control ofB. abortusinfection. Additionally,B. abortus-infected dendritic cells require TLR6 to induce tumor necrosis factor alpha (TNF-α) and interleukin-12 (IL-12). Furthermore, our findings demonstrated that the mitogen-activated protein kinase (MAPK) signaling pathway is impaired in TLR2, TLR6, and TLR2/6 knockout (KO) DCs when infected withB. abortus, which may account for the lower proinflammatory cytokine production observed in TLR6 KO mouse dendritic cells. In summary, the results presented here indicate that TLR6 is required to trigger innate immune responses againstB. abortusin vivoand is required for the full activation of DCs to induce robust proinflammatory cytokine production.

scholarly journals Cytadherence of Mycoplasma pneumoniae Induces Inflammatory Responses through Autophagy and Toll-Like Receptor 4

2014 ◽  
Vol 82 (7) ◽  
pp. 3076-3086 ◽  
Author(s):  
Takashi Shimizu ◽  
Yui Kimura ◽  
Yutaka Kida ◽  
Koichi Kuwano ◽  
Masato Tachibana ◽  
...  
Keyword(s):  
Immune Responses ◽  
Mycoplasma Pneumoniae ◽  
Cytokine Production ◽  
Inflammatory Responses ◽  
Hypothetical Protein ◽  
Toll Like Receptor ◽  
Wild Type ◽  
Toll Like Receptor 4 ◽  
Content Type ◽  
Toll Like Receptor 2

ABSTRACTMycoplasma pneumoniaecauses pneumonia, tracheobronchitis, pharyngitis, and asthma in humans. The pathogenesis ofM. pneumoniaeinfection is attributed to excessive immune responses. We previously demonstrated thatM. pneumoniaelipoproteins induced inflammatory responses through Toll-like receptor 2 (TLR2). In the present study, we demonstrated thatM. pneumoniaeinduced strong inflammatory responses in macrophages derived from TLR2 knockout (KO) mice. Cytokine production in TLR2 KO macrophages was increased compared with that in the macrophages of wild-type (WT) mice. Heat-killed, antibiotic-treated, and overgrownM. pneumoniaefailed to induce inflammatory responses in TLR2 KO macrophages. 3-Methyladenine and chloroquine, inhibitors of autophagy, decreased the induction of inflammatory responses in TLR2 KO macrophages. These inflammatory responses were also inhibited in macrophages treated with the TLR4 inhibitor VIPER and those obtained from TLR2 and TLR4 (TLR2/4) double-KO mice. Two mutants that lacked the ability to induce inflammatory responses in TLR2 KO macrophages were obtained by transposon mutagenesis. The transposons were inserted inatpCencoding an ATP synthase F0F1 ε subunit andF10_orf750encoding hypothetical protein MPN333. These mutants showed deficiencies in cytadherence. These results suggest that cytadherence ofM. pneumoniaeinduces inflammatory responses through TLR4 and autophagy.

scholarly journals Lipids Derived from Virulent Francisella tularensis Broadly Inhibit Pulmonary Inflammation via Toll-Like Receptor 2 and Peroxisome Proliferator-Activated Receptor α

2013 ◽  
Vol 20 (10) ◽  
pp. 1531-1540 ◽  
Author(s):  
Deborah D. Crane ◽  
Robin Ireland ◽  
Joshua B. Alinger ◽  
Pamela Small ◽  
Catharine M. Bosio
Keyword(s):  
Francisella Tularensis ◽  
Inflammatory Responses ◽  
Pulmonary Inflammation ◽  
Host Cells ◽  
Peroxisome Proliferator ◽  
Toll Like Receptor ◽  
Peroxisome Proliferator Activated Receptor ◽  
Content Type ◽  
Host Immune Responses

ABSTRACTFrancisella tularensisis a Gram-negative facultative intracellular pathogen that causes an acute lethal respiratory disease in humans. The heightened virulence of the pathogen is linked to its unique ability to inhibit Toll-like receptor (TLR)-mediated inflammatory responses. The bacterial component and mechanism of this inhibition are unknown. Here we show that lipids isolated from virulent but not attenuated strains ofF. tularensisare not detected by host cells, inhibit production of proinflammatory cytokines by primary macrophages in response to known TLR ligands, and suppress neutrophil recruitmentin vivo. We further show that lipid-mediated inhibition of inflammation is dependent on TLR2, MyD88, and the nuclear hormone and fatty acid receptor peroxisome proliferator-activated receptor α (PPARα). Pathogen lipid-mediated interference with inflammatory responses through the engagement of TLR2 and PPARα represents a novel manipulation of host signaling pathways consistent with the ability of highly virulentF. tularensisto efficiently evade host immune responses.

scholarly journals Sex differences in the pro-inflammatory cytokine response to endotoxin unfold in vivo but not ex vivo in healthy humans

2017 ◽  
Vol 23 (5) ◽  
pp. 432-439 ◽  
Author(s):  
Alexander Wegner ◽  
Sven Benson ◽  
Laura Rebernik ◽  
Ingo Spreitzer ◽  
Marcus Jäger ◽  
...  
Keyword(s):  
Sex Differences ◽  
Inflammatory Response ◽  
Plasma Cortisol ◽  
Cytokine Production ◽  
Inflammatory Responses ◽  
Ex Vivo ◽  
Negative Feedback Regulation ◽  
Healthy Humans ◽  
Tnf Α

Clinical data indicate that inflammatory responses differ across sexes, but the mechanisms remain elusive. Herein, we assessed in vivo and ex vivo cytokine responses to bacterial endotoxin in healthy men and women to elucidate the role of systemic and cellular factors underlying sex differences in inflammatory responses. Participants received an i.v. injection of low-dose endotoxin (0.4 ng/kg body mass), and plasma TNF-α and IL-6 responses were analyzed over a period of 6 h. In parallel, ex vivo cytokine production was measured in endotoxin-stimulated blood samples obtained immediately before in vivo endotoxin administration. As glucocorticoids (GCs) play an important role in the negative feedback regulation of the inflammatory response, we additionally analyzed plasma cortisol concentrations and ex vivo GC sensitivity of cytokine production. Results revealed greater in vivo pro-inflammatory responses in women compared with men, with significantly higher increases in plasma TNF-α and IL-6 concentrations. In addition, the endotoxin-induced rise in plasma cortisol was more pronounced in women. In contrast, no sex differences in ex vivo cytokine production and GC sensitivity were observed. Together, these findings demonstrate major differences in in vivo and ex vivo responses to endotoxin and underscore the importance of systemic factors underlying sex differences in the inflammatory response.

scholarly journals Akkermansia muciniphila and Its Pili-Like Protein Amuc_1100 Modulate Macrophage Polarization in Experimental Periodontitis

2020 ◽  
Vol 89 (1) ◽  
pp. e00500-20
Author(s):  
Hannah Mulhall ◽  
Jeanne M. DiChiara ◽  
Matthew Deragon ◽  
Radha Iyer ◽  
Olivier Huck ◽  
...  
Keyword(s):  
Bone Loss ◽  
Alveolar Bone ◽  
Macrophage Polarization ◽  
Alveolar Bone Loss ◽  
Oral Microbiome ◽  
Content Type ◽  
Akkermansia Muciniphila ◽  
Periodontal Inflammation ◽  
Experimental Periodontitis ◽  
Anti Inflammatory

ABSTRACTPeriodontitis is a chronic inflammatory disease triggered by dysbiosis of the oral microbiome. Porphyromonas gingivalis is strongly implicated in periodontal inflammation, gingival tissue destruction, and alveolar bone loss through sustained exacerbation of the host response. Recently, the use of other bacterial species, such as Akkermansia muciniphila, has been suggested to counteract inflammation elicited by P. gingivalis. In this study, the effects of A. muciniphila and its pili-like protein Amuc_1100 on macrophage polarization during P. gingivalis infection were evaluated in a murine model of experimental periodontitis. Mice were gavaged with P. gingivalis alone or in combination with A. muciniphila or Amuc_1100 for 6 weeks. Morphometric analysis demonstrated that the addition of A. muciniphila or Amuc_1100 significantly reduced P. gingivalis-induced alveolar bone loss. This decreased bone loss was associated with a proresolutive phenotype (M2) of macrophages isolated from submandibular lymph nodes as observed by flow cytometry. Furthermore, the expression of interleukin 10 (IL-10) at the RNA and protein levels was significantly increased in the gingival tissues of the mice and in macrophages exposed to A. muciniphila or Amuc_1100, confirming their anti-inflammatory properties. This study demonstrates the putative therapeutic interest of the administration of A. muciniphila or Amuc_1100 in the management of periodontitis through their anti-inflammatory properties.

scholarly journals Transcriptomic Analysis of Inbred Chicken Lines Reveals Infectious Bursal Disease Severity Is Associated with Greater Bursal Inflammation In Vivo and More Rapid Induction of Pro-Inflammatory Responses in Primary Bursal Cells Stimulated Ex Vivo

Viruses ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 933
Author(s):  
Amin S. Asfor ◽  
Salik Nazki ◽  
Vishwanatha R.A.P. Reddy ◽  
Elle Campbell ◽  
Katherine L. Dulwich ◽  
...  
Keyword(s):  
Rho Gtpases ◽  
Inflammatory Responses ◽  
Ex Vivo ◽  
Severe Disease ◽  
Infectious Bursal Disease ◽  
Rna Seq ◽  
Rapid Induction ◽  
Cytoskeletal Regulation ◽  
Bursal Disease

In order to better understand differences in the outcome of infectious bursal disease virus (IBDV) infection, we inoculated a very virulent (vv) strain into White Leghorn chickens of inbred line W that was previously reported to experience over 24% flock mortality, and three inbred lines (15I, C.B4 and 0) that were previously reported to display no mortality. Within each experimental group, some individuals experienced more severe disease than others but line 15I birds experienced milder disease based on average clinical scores, percentage of birds with gross pathology, average bursal lesion scores and average peak bursal virus titre. RNA-Seq analysis revealed that more severe disease in line W was associated with significant up-regulation of pathways involved in inflammation, cytoskeletal regulation by Rho GTPases, nicotinic acetylcholine receptor signaling, and Wnt signaling in the bursa compared to line 15I. Primary bursal cell populations isolated from uninfected line W birds contained a significantly greater percentage of KUL01+ macrophages than cells isolated from line 15I birds (p < 0.01) and, when stimulated ex vivo with LPS, showed more rapid up-regulation of pro-inflammatory gene expression than those from line 15I birds. We hypothesize that a more rapid induction of pro-inflammatory cytokine responses in bursal cells following IBDV infection leads to more severe disease in line W birds than in line 15I.

scholarly journals Interaction of periodontitis and orthodontic tooth movement—an in vitro and in vivo study

2021 ◽  
Author(s):  
Birgit Rath-Deschner ◽  
Andressa V. B. Nogueira ◽  
Svenja Beisel-Memmert ◽  
Marjan Nokhbehsaim ◽  
Sigrun Eick ◽  
...  
Keyword(s):  
Alveolar Bone ◽  
Tooth Movement ◽  
Mechanical Strain ◽  
Orthodontic Tooth Movement ◽  
Fusobacterium Nucleatum ◽  
In Vivo Study ◽  
Rt Pcr ◽  
Periodontal Inflammation

Abstract Objectives The aim of this in vitro and in vivo study was to investigate the interaction of periodontitis and orthodontic tooth movement on interleukin (IL)-6 and C-X-C motif chemokine 2 (CXCL2). Materials and methods The effect of periodontitis and/or orthodontic tooth movement (OTM) on alveolar bone and gingival IL-6 and CXCL2 expressions was studied in rats by histology and RT-PCR, respectively. The animals were assigned to four groups (control, periodontitis, OTM, and combination of periodontitis and OTM). The IL-6 and CXCL2 levels were also studied in human gingival biopsies from periodontally healthy and periodontitis subjects by RT-PCR and immunohistochemistry. Additionally, the synthesis of IL-6 and CXCL2 in response to the periodontopathogen Fusobacterium nucleatum and/or mechanical strain was studied in periodontal fibroblasts by RT-PCR and ELISA. Results Periodontitis caused an increase in gingival levels of IL-6 and CXCL2 in the animal model. Moreover, orthodontic tooth movement further enhanced the bacteria-induced periodontal destruction and gingival IL-6 gene expression. Elevated IL-6 and CXCL2 gingival levels were also found in human periodontitis. Furthermore, mechanical strain increased the stimulatory effect of F. nucleatum on IL-6 protein in vitro. Conclusions Our study suggests that orthodontic tooth movement can enhance bacteria-induced periodontal inflammation and thus destruction and that IL-6 may play a pivotal role in this process. Clinical relevance Orthodontic tooth movement should only be performed after periodontal therapy. In case of periodontitis relapse, orthodontic therapy should be suspended until the periodontal inflammation has been successfully treated and thus the periodontal disease is controlled again.

scholarly journals Ex VivoMaturation Assay for Testing Antimalarial Sensitivity of Rodent Malaria Parasites

2016 ◽  
Vol 60 (11) ◽  
pp. 6859-6866 ◽  
Author(s):  
Zi Wei Chang ◽  
Benoit Malleret ◽  
Bruce Russell ◽  
Laurent Rénia ◽  
Carla Claser
Keyword(s):  
Ex Vivo ◽  
Single Step ◽  
Parasite Development ◽  
Ring Stage ◽  
Malaria Parasites ◽  
Rodent Malaria ◽  
Content Type ◽  
Parasite Biology

ABSTRACTEx vivoassay systems provide a powerful approach to studying human malaria parasite biology and to testing antimalarials. For rodent malaria parasites, short-termin vitroculture andex vivoantimalarial susceptibility assays are relatively cumbersome, relying onin vivopassage for synchronization, since ring-stage parasites are an essential starting material. Here, we describe a new approach based on the enrichment of ring-stagePlasmodium berghei,P. yoelii, andP. vinckei vinckeiusing a single-step Percoll gradient. Importantly, we demonstrate that the enriched ring-stage parasites develop synchronously regardless of the parasite strain or species used. Using a flow cytometry assay with Hoechst and ethidium or MitoTracker dye, we show that parasite development is easily and rapidly monitored. Finally, we demonstrate that this approach can be used to screen antimalarial drugs.

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