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 Mycobacterium tuberculosisLipoprotein and Lipoglycan Binding to Toll-Like Receptor 2 Correlates with Agonist Activity and Functional Outcomes

2018 ◽  
Vol 86 (10) ◽  
Author(s):  
Supriya Shukla ◽  
Edward T. Richardson ◽  
Michael G. Drage ◽  
W. Henry Boom ◽  
Clifford V. Harding
Keyword(s):  
Immune Responses ◽  
Agonist Activity ◽  
Toll Like Receptor ◽  
Necrosis Factor Alpha ◽  
Tlr2 Agonist ◽  
Content Type ◽  
Host Immune Responses ◽  
Extracellular Signal ◽  
Toll Like Receptor 2 ◽  
Tlr2 Signaling

ABSTRACTMycobacterium tuberculosiscauses persistent infection due to its ability to evade host immune responses.M. tuberculosisinduces Toll-like receptor 2 (TLR2) signaling, which influences immune responses toM. tuberculosis. TLR2 agonists expressed byM. tuberculosisinclude lipoproteins (e.g., LprG), the glycolipid phosphatidylinositol mannoside 6 (PIM6), and the lipoglycan lipomannan (LM). AnotherM. tuberculosislipoglycan, mannose-capped lipoarabinomannan (ManLAM), lacks TLR2 agonist activity. In contrast, PILAM, fromMycobacterum smegmatis, does have TLR2 agonist activity. Our understanding of howM. tuberculosislipoproteins and lipoglycans interact with TLR2 is limited, and binding of these molecules to TLR2 has not been measured directly. Here, we directly measuredM. tuberculosislipoprotein and lipoglycan binding to TLR2 and its partner receptor, TLR1. LprG, LAM, and LM were all found to bind to TLR2 in the absence of TLR1, but not to TLR1 in the absence of TLR2. Trimolecular interactions were revealed by binding of TLR2-LprG or TLR2-PIM6 complexes to TLR1, whereas binding of TLR2 to TLR1 was not detected in the absence of the lipoprotein or glycolipid. ManLAM exhibited low affinity for TLR2 in comparison to PILAM, LM, and LprG, which correlated with reduced ability of ManLAM to induce TLR2-mediated extracellular-signal-regulated kinase (ERK) activation and tumor necrosis factor alpha (TNF-α) secretion in macrophages. We provide the first direct affinity measurement and kinetic analysis ofM. tuberculosislipoprotein and lipoglycan binding to TLR2. Our results demonstrate that binding affinity correlates with the functional ability of agonists to induce TLR2 signaling.

scholarly journals Talin1 controls dendritic cell activation by regulating TLR complex assembly and signaling

2020 ◽  
Vol 217 (8) ◽  
Author(s):  
Thomas Jun Feng Lim ◽  
Maegan Bunjamin ◽  
Christiane Ruedl ◽  
I-hsin Su
Keyword(s):  
Immune Responses ◽  
Cell Activation ◽  
Cytokine Production ◽  
Inflammatory Responses ◽  
Tolerance Induction ◽  
Direct Interaction ◽  
Toll Like Receptor ◽  
Dendritic Cell Activation ◽  
Dependent Cell ◽  
Draining Lymph Nodes

Talin critically controls integrin-dependent cell migration, but its regulatory role in skin dendritic cells (DCs) during inflammatory responses has not been investigated. Here, we show that talin1 regulates not only integrin-dependent Langerhans cell (LC) migration, but also MyD88-dependent Toll-like receptor (TLR)–stimulated DC activation. Talin1-deficient LCs failed to exit the epidermis, resulting in reduced LC migration to skin-draining lymph nodes (sdLNs) and defective skin tolerance induction, while talin1-deficient dermal DCs unexpectedly accumulated in the dermis despite their actomyosin-dependent migratory capabilities. Furthermore, talin1-deficient DCs exhibited compromised chemotaxis, NFκB activation, and proinflammatory cytokine production. Mechanistically, talin1 was required for the formation of preassembled TLR complexes in DCs at steady state via direct interaction with MyD88 and PIP5K. Local production of PIP2 by PIP5K then recruited TIRAP to the preassembled complexes, which were required for TLR signalosome assembly during DC activation. Thus, talin1 regulates MyD88-dependent TLR signaling pathways in DCs through a novel mechanism with implications for antimicrobial and inflammatory immune responses.

scholarly journals Staphylococcus aureus Releases Proinflammatory Membrane Vesicles To Resist Antimicrobial Fatty Acids

mSphere ◽  
2020 ◽  
Vol 5 (5) ◽  
Author(s):  
Arnaud Kengmo Tchoupa ◽  
Andreas Peschel
Keyword(s):  
Fatty Acids ◽  
Staphylococcus Aureus ◽  
Immune Responses ◽  
Membrane Vesicle ◽  
Membrane Vesicles ◽  
Innate Immune ◽  
Toll Like Receptor ◽  
Content Type ◽  
Healthy Humans ◽  
Toll Like Receptor 2

ABSTRACT Staphylococcus aureus is a major pathogen, which colonizes one in three otherwise healthy humans. This significant spread of S. aureus is largely due to its ability to circumvent innate immune responses, including antimicrobial fatty acids (AFAs) on the skin and in nasal secretions. In response to AFAs, S. aureus swiftly induces resistance mechanisms, which have yet to be completely elucidated. Here, we identify membrane vesicle (MV) release as a resistance strategy used by S. aureus to sequester host-specific AFAs. MVs protect S. aureus against a wide array of AFAs. Strikingly, beside MV production, S. aureus modulates MV composition upon exposure to AFAs. MVs purified from bacteria grown in the presence of linoleic acid display a distinct protein content and are enriched in lipoproteins, which strongly activate Toll-like receptor 2 (TLR2). Cumulatively, our findings reveal the protective capacities of MVs against AFAs, which are counteracted by an increased TLR2-mediated innate immune response. IMPORTANCE The nares of one in three humans are colonized by Staphylococcus aureus. In these environments, and arguably on all mucosal surfaces, bacteria encounter fatty acids with antimicrobial properties. Our study uncovers that S. aureus releases membrane vesicles (MVs) that act as decoys to protect the bacterium against antimicrobial fatty acids (AFAs). The AFA-neutralizing effects of MVs were neither strain specific nor restricted to one particular AFA. Hence, MVs may represent “public goods” playing an overlooked role in shaping bacterial communities in AFA-rich environments such as the skin and nose. Intriguingly, in addition to MV biogenesis, S. aureus modulates MV composition in response to exposure to AFAs, including an increased release of lipoproteins. These MVs strongly stimulate the innate immunity via Toll-like receptor 2 (TLR2). TLR2-mediated inflammation, which helps to fight infections, may exacerbate inflammatory disorders like atopic dermatitis. Our study highlights intricate immune responses preventing infections from colonizing bacteria.

scholarly journals Toll-Like Receptor 9 Modulates Immune Responses to Aspergillus fumigatus Conidia in Immunodeficient and Allergic Mice

2008 ◽  
Vol 77 (1) ◽  
pp. 108-119 ◽  
Author(s):  
Hemanth Ramaprakash ◽  
Toshihiro Ito ◽  
Theodore J. Standiford ◽  
Steven L. Kunkel ◽  
Cory M. Hogaboam
Keyword(s):  
Immune Responses ◽  
Aspergillus Fumigatus ◽  
Inflammatory Responses ◽  
Fungal Growth ◽  
Lower Airway ◽  
Interleukin 17 ◽  
Toll Like Receptor ◽  
Wild Type ◽  
Immunodeficient Mice

ABSTRACT The role of Toll-like receptor 9 (TLR9) in antifungal responses in the immunodeficient and allergic host is unclear. We investigated the role of TLR9 in murine models of invasive aspergillosis and fungal asthma. Neutrophil-depleted TLR9 wild-type (TLR9+/+) and TLR9-deficient (TLR9−/−) mice were challenged with resting or swollen Aspergillus fumigatus conidia and monitored for survival and lung inflammatory responses. The absence of TLR9 delayed, but did not prevent, mortality in immunodeficient mice challenged with resting or swollen conidia compared to TLR9+/+ mice. In a fungal asthma model, TLR9+/+ and TLR9−/− mice were sensitized to soluble A. fumigatus antigens and challenged with resting or swollen A. fumigatus conidia, and both groups of mice were analyzed prior to and at days 7, 14, and 28 after the conidium challenge. When challenged with resting conidia, TLR9−/− mice exhibited significantly lower airway hyper-responsiveness compared to the TLR9+/+ groups. In contrast, A. fumigatus-sensitized TLR9−/− mice exhibited pulmonary fungal growth at days 14 and 28 after challenge with swollen conidia, a finding never observed in their allergic wild-type counterparts. Increased fungal growth in allergic TLR9−/− mice correlated with markedly decreased dectin-1 expression in whole lung samples and isolated dendritic cell populations. Further, whole lung levels of interleukin-17 were lower in allergic TLR9−/− mice compared to similar TLR9+/+ mice. Together, these data suggest that TLR9 modulates pulmonary antifungal immune responses to swollen conidia, possibly through the regulation of dectin-1 expression.

scholarly journals Relationship between Arg753Gln Toll-like receptor 2 and Asp299Gly Toll-like receptor 4 genetic variations and susceptibility to colorectal cancer in Southern Iran

2018 ◽  
Vol 70 (4) ◽  
pp. 775-779 ◽  
Author(s):  
Seyed Hosseini ◽  
Zahra Mojtahedi ◽  
Zahra Beizavi ◽  
Hajar Khazraei ◽  
Mozhdeh Zamani
Keyword(s):  
Colorectal Cancer ◽  
Cancer Patients ◽  
Inflammatory Responses ◽  
Tumor Stage ◽  
Nucleotide Polymorphisms ◽  
Toll Like Receptor ◽  
Toll Like Receptor 4 ◽  
Southern Iran ◽  
Toll Like Receptor 2 ◽  
Colorectal Cancer Patients

Variations in Toll-like receptor 2 (TLR2) and Toll-like receptor 4 (TLR4) encoding genes have been associated with tumorigenesis through the disruption of immune and inflammatory responses. The aims of this study were to evaluate the two single nucleotide polymorphisms (SNPs) of the genes Arg753Gln TLR2 (rs5743708) and Asp299Gly TLR4 (rs4986790) in colorectal cancer patients in southern Iran. Colorectal cancer patients and healthy controls were included in this study (150 Persian subjects in each group). Blood samples were used for genotyping by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. The association between these SNPs and colorectal cancer and clinicopathological factors, including age, gender, tumor stage and differentiation were also investigated. A significant association was found between Arg753Gln TLR2 SNP and colorectal cancer. This SNP was significantly more frequent in male patients. However, there was no association between Asp299Gly TLR4 and colorectal cancer. Therefore, Arg753Gln TLR2 SNP can be considered as a risk factor for colorectal cancer incidence in southern Iran, especially in men. Further investigations in other populations are recommended in order to assess the association of this SNP with colorectal cancer.

scholarly journals Toll-Like Receptor 2 Agonist Pam3CSK4 Alleviates the Pathology of Leptospirosis in Hamster

2016 ◽  
Vol 84 (12) ◽  
pp. 3350-3357 ◽  
Author(s):  
Wenlong Zhang ◽  
Naisheng Zhang ◽  
Xufeng Xie ◽  
Jian Guo ◽  
Xuemin Jin ◽  
...  
Keyword(s):  
Tissue Injury ◽  
Interleukin 10 ◽  
Peritoneal Macrophages ◽  
High Ratio ◽  
Toll Like Receptor ◽  
Wild Type ◽  
Necrosis Factor Alpha ◽  
Content Type ◽  
Target Organs ◽  
Toll Like Receptor 2

Leptospirosis, caused by pathogenic spirochetes, is a zoonotic disease of global importance. The detailed pathogenesis of leptospirosis is still unclear, which limits the ideal treatment of leptospirosis. In this study, we analyzed the expression of Toll-like receptor 2 (TLR2) and TLR4 in target organs of both resistant mice and susceptible hamsters after Leptospira interrogans serovar Autumnalis infection. TLR2 but not TLR4 transcripts in mouse organs contrasted with delayed induction and overexpression in hamster organs. Coinjection of leptospires and the TLR2 agonist Pam3CSK4 into hamsters improved their survival rate, alleviated tissue injury, and decreased the abundance of leptospires in target organs. The production of interleukin-10 (IL-10) from tissues was enhanced in hamsters of the group coinjected with leptospires and Pam3CSK4 compared with the leptospira-injected group. Similarly, IL-10 levels in TLR2-deficient mice were lower than those in wild-type mice. A high ratio of IL-10/tumor necrosis factor alpha (TNF-α) levels was found in both infected wild-type mice and hamsters coinjected with leptospires and Pam3CSK4. Moreover, TLR2-dependent IL-10 expression was detected in peritoneal macrophages after leptospira infection. Our data demonstrate that coinjection of leptospires and Pam3CSK4 alleviates the pathology of leptospirosis in hamsters; this effect may result from the enhanced expression of TLR2-dependent IL-10.

scholarly journals Roles of Toll-Like Receptor 2 (TLR2), TLR4, and MyD88 during Pulmonary Coxiella burnetii Infection

2016 ◽  
Vol 84 (4) ◽  
pp. 940-949 ◽  
Author(s):  
Andrew G. Ramstead ◽  
Amanda Robison ◽  
Anne Blackwell ◽  
Maria Jerome ◽  
Brett Freedman ◽  
...  
Keyword(s):  
Immune Responses ◽  
Coxiella Burnetii ◽  
Bacterial Growth ◽  
Pulmonary Infection ◽  
Innate Immune ◽  
Toll Like Receptor ◽  
Content Type ◽  
Link Type ◽  
Peripheral Infection ◽  
Toll Like Receptor 2

Coxiella burnetii, the causative agent of Q fever, is an obligate intracellular, primarily pulmonary, bacterial pathogen. Although much is known about adaptive immune responses against this bacterium, our understanding of innate immune responses againstC. burnetiiis not well defined, particularly within the target tissue for infection, the lung. Previous studies examined the roles of the innate immune system receptors Toll-like receptor 2 (TLR2) and TLR4 in peripheral infection models and described minimal phenotypes in specific gene deletion animals compared to those of their wild-type controls (S. Meghari et al., Ann N Y Acad Sci 1063:161–166, 2005,http://dx.doi.org/10.1196/annals.1355.025; A. Honstettre et al., J Immunol 172:3695–3703, 2004,http://dx.doi.org/10.4049/jimmunol.172.6.3695) . Here, we assessed the roles for TLR2, TLR4, and MyD88 in pulmonaryC. burnetiiinfection and compared responses to those that occurred in TLR2- and TLR4-deficient animals following peripheral infection. As observed previously, neither TLR2 nor TLR4 was needed for limiting bacterial growth after peripheral infection. In contrast, TLR2 and, to a lesser extent, TLR4 limited growth (or dissemination) of the bacterium in the lung and spleen after pulmonary infection. TLR2, TLR4, and MyD88 were not required for the general inflammatory response in the lungs after pulmonary infection. However, MyD88 signaling was important for infection-induced morbidity. Finally, TLR2 expression on hematopoietic cells was most important for limiting bacterial growth in the lung. These results expand on our knowledge of the roles for TLR2 and TLR4 inC. burnetiiinfection and suggest various roles for these receptors that are dictated by the site of infection.

scholarly journals Dietary Silk Peptide Inhibits LPS-Induced Inflammatory Responses by Modulating Toll-Like Receptor 4 (TLR4) Signaling

Biomolecules ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 771
Author(s):  
Sungwoo Chei ◽  
Hyun-Ji Oh ◽  
Kippeum Lee ◽  
Heegu Jin ◽  
Jeong-Yong Lee ◽  
...  
Keyword(s):  
Immune Responses ◽  
Signaling Pathway ◽  
Inflammatory Responses ◽  
Innate Immune Responses ◽  
Toll Like Receptor ◽  
Serum Samples ◽  
Toll Like Receptor 4 ◽  
Tlr4 Signaling ◽  
Tlr4 Signaling Pathway ◽  
Silk Peptide

Acid-hydrolyzed silk peptide (SP) is a valuable material that has been used traditionally to treat various diseases, however, the mechanism by which it affects inflammatory responses is unknown. To examine the effects of SP on inflammatory responses, we used macrophages as a vehicle for examining signaling via toll-like receptor 4 (TLR4), which plays an important role in innate immune responses to pathogenic infections and pathogen-derived molecules such as lipopolysaccharide (LPS). We then confirmed the anti-inflammatory effects of SP by examining lymph node, spleen, and serum samples from C57BL/6 mice injected with LPS. We also used LPS-induced bone marrow-derived macrophages and RAW264.7 cells (a murine macrophage cell line) to identify the mechanism by which SP modulates immune responses via the TLR4 signaling pathway. In addition, we showed that SP prevents LPS-induced production of nitric oxide and reactive oxygen species. In summary, SP inhibits LPS-induced inflammatory responses by modulating the TLR4 signaling pathway.

scholarly journals Difference in Strain Pathogenicity of Septicemic Yersinia pestis Infection in a TLR2−/− Mouse Model

2020 ◽  
Vol 88 (3) ◽  
Author(s):  
Kyle L. O’Donnell ◽  
Peter L. Knopick ◽  
Riley Larsen ◽  
Sanghita Sarkar ◽  
Matthew L. Nilles ◽  
...  
Keyword(s):  
Yersinia Pestis ◽  
Cytokine Production ◽  
Immune Cell ◽  
Neutrophil Infiltration ◽  
Cell Trafficking ◽  
Toll Like Receptor ◽  
Inflammatory Cytokine Production ◽  
Content Type ◽  
Immune Cell Trafficking ◽  
Toll Like Receptor 2

ABSTRACT Yersinia pestis is the causative agent of bubonic, pneumonic, and septicemic plague. We demonstrate that Toll-like receptor 2-deficient (TLR2−/−) mice are resistant to septicemic infection by the KIM5 strain of Y. pestis but not to infection by the CO92 Δpgm strain. This resistance is dependent on TLR2, the route of infection, and the isoform of YopJ. Elevated bacterial burdens were found in the spleens of CO92 Δpgm-infected animals by 24 h postinfection and in the livers by 4 days. The YopJ isoform present contributed directly to cytotoxicity and inflammatory cytokine production of bone marrow-derived macrophages from TLR2−/− mice. Immune cell trafficking is altered in CO92 Δpgm infections, with an increased neutrophil infiltration to the spleen 5 days postinfection. Immune cell infiltration to the liver was greater and earlier in KIM5-infected TLR2−/− mice. The functionality of the immune cells was assessed by the ability to develop reactive oxygen and nitrogen species. Our data suggest an inhibition of granulocytes in forming these species in CO92 Δpgm-infected TLR2−/− mice. These findings suggest that resistance to KIM5 in TLR2−/− mice is dependent on early immune cell trafficking and functionality.

scholarly journals Toll-Like Receptor 2 Represses Nonpilus Adhesin-Induced Signaling in Acute Infections with the Pseudomonas aeruginosa pilA Mutant

2004 ◽  
Vol 72 (8) ◽  
pp. 4561-4569 ◽  
Author(s):  
Eva Lorenz ◽  
Diana C. Chemotti ◽  
Karen Vandal ◽  
Philippe A. Tessier
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Host Response ◽  
Lavage Fluid ◽  
Toll Like Receptor ◽  
Wild Type ◽  
Toll Like Receptor 4 ◽  
Acute Infections ◽  
Associated Proteins ◽  
Important Means ◽  
Toll Like Receptor 2

ABSTRACT Expression of pili and associated proteins is an important means of host invasion by bacterial pathogens. Recent evidence has suggested that the binding of Pseudomonas aeruginosa through nonpilus adhesins may also be important in respiratory diseases, since adhesins bind mucins. Using wild-type C57BL/6 and TLR2KO mice, we compared the induction levels of the host response to P. aeruginosa that either expressed pili or lacked pilus expression due to a mutation in the structural gene pilA. In C57BL/6 mice, deletion of pili led to a decreased immune response, evidenced by a lower secretion of cytokines and a lack of neutrophil chemotaxis. By contrast, the P. aeruginosa pilA mutant induced a hyperresponsive phenotype in TLR2KO mice. TLR2KO mice showed an increased number of neutrophils in lavage fluid compared to the levels seen when either mouse strain was exposed to wild-type P. aeruginosa. Further analysis indicated that the increased neutrophil influx was associated with an increased expression of calgranulins, possibly through an induction of Toll-like receptor 4 (TLR4) expression. The hyperresponsive phenotype of TLR2KO mice exposed to the P. aeruginosa pilA mutant was associated with TLR4 induction and indicated that nonpilus adhesin-induced signaling was repressed by TLR2 function and, if not blocked by the host, could induce airway hyperresponsiveness.

Sign in / Sign up

Export Citation Format

Share Document