Synthetic molecules and functionalized nanoparticles targeting the LPS-TLR4 signaling: A new generation of immunotherapeutics

2011 ◽  
Vol 84 (1) ◽  
pp. 97-106 ◽  
Author(s):  
Francesco Peri ◽  
Valentina Calabrese ◽  
Matteo Piazza ◽  
Roberto Cighetti
Keyword(s):  
Myeloid Differentiation ◽  
Vaccine Adjuvants ◽  
Toll Like Receptor ◽  
Differentiation Antigen ◽  
Toll Like Receptor 4 ◽  
Tlr4 Signaling ◽  
Bacterial Endotoxins ◽  
Pharmacological Interest ◽  
Tlr4 Activation ◽  
New Generation

Toll-like receptor 4 (TLR4), the receptor of bacterial endotoxins in mammalians, plays a pivotal role in the induction of innate immunity and inflammation. TLR4 activation by bacterial lipopolysaccharide (LPS) is achieved by the coordinate and sequential action of three other proteins, the lipopolysaccharide binding protein (LBP), the cluster differentiation antigen CD14, and the myeloid differentiation protein (MD-2) receptors, that bind LPS and present it in a monomeric form to TLR4 by forming the activated [TLR4·MD-2·LPS]2 complex. Small molecules and nanoparticles active in modulating the TLR4 signal by targeting directly the MD-2·TLR4 complex or by interfering in other points of the TLR4 signaling are presented in this paper. These compounds have great pharmacological interest as vaccine adjuvants, immunotherapeutics, anti-sepsis, and anti-inflammatory agents.

scholarly journals Respiratory Syncytial Virus Fusion Protein-Induced Toll-Like Receptor 4 (TLR4) Signaling Is Inhibited by the TLR4 Antagonists Rhodobacter sphaeroides Lipopolysaccharide and Eritoran (E5564) and Requires Direct Interaction with MD-2

mBio ◽  
2012 ◽  
Vol 3 (4) ◽  
Author(s):  
Prasad Rallabhandi ◽  
Rachel L. Phillips ◽  
Marina S. Boukhvalova ◽  
Lioubov M. Pletneva ◽  
Kari Ann Shirey ◽  
...  
Keyword(s):  
Respiratory Syncytial Virus ◽  
Rhodobacter Sphaeroides ◽  
Dependent Manner ◽  
Toll Like Receptor ◽  
Toll Like Receptor 4 ◽  
Tlr4 Signaling ◽  
F Protein ◽  
Terminal Domain ◽  
Syncytial Virus ◽  
Tlr4 Activation

ABSTRACTRespiratory syncytial virus (RSV) is a leading cause of infant mortality worldwide. Toll-like receptor 4 (TLR4), a signaling receptor for structurally diverse microbe-associated molecular patterns, is activated by the RSV fusion (F) protein and by bacterial lipopolysaccharide (LPS) in a CD14-dependent manner. TLR4 signaling by LPS also requires the presence of an additional protein, MD-2. Thus, it is possible that F protein-mediated TLR4 activation relies on MD-2 as well, although this hypothesis has not been formally tested. LPS-free RSV F protein was found to activate NF-κB in HEK293T transfectants that express wild-type (WT) TLR4 and CD14, but only when MD-2 was coexpressed. These findings were confirmed by measuring F-protein-induced interleukin 1β (IL-1β) mRNA in WT versus MD-2−/−macrophages, where MD-2−/−macrophages failed to show IL-1β expression upon F-protein treatment, in contrast to the WT. BothRhodobacter sphaeroidesLPS and synthetic E5564 (eritoran), LPS antagonists that inhibit TLR4 signaling by binding a hydrophobic pocket in MD-2, significantly reduced RSV F-protein-mediated TLR4 activity in HEK293T-TLR4–CD14–MD-2 transfectants in a dose-dependent manner, while TLR4-independent NF-κB activation by tumor necrosis factor alpha (TNF-α) was unaffected.In vitrocoimmunoprecipitation studies confirmed a physical interaction between native RSV F protein and MD-2. Further, we demonstrated that the N-terminal domain of the F1 segment of RSV F protein interacts with MD-2. These data provide new insights into the importance of MD-2 in RSV F-protein-mediated TLR4 activation. Thus, targeting the interaction between MD-2 and RSV F protein may potentially lead to novel therapeutic approaches to help control RSV-induced inflammation and pathology.IMPORTANCEThis study shows for the first time that the fusion (F) protein of respiratory syncytial virus (RSV), a major cause of bronchiolitis and death, particularly in infants and young children, physically interacts with the Toll-like receptor 4 (TLR4) coreceptor, MD-2, through its N-terminal domain. We show that F protein-induced TLR4 activation can be blocked by lipid A analog antagonists. This observation provides a strong experimental rationale for testing such antagonists in animal models of RSV infection for potential use in people.

scholarly journals MyD88, but Not Toll-Like Receptors 4 and 2, Is Required for Efficient Clearance of Brucella abortus

2005 ◽  
Vol 73 (8) ◽  
pp. 5137-5143 ◽  
Author(s):  
David S. Weiss ◽  
Kiyoshi Takeda ◽  
Shizuo Akira ◽  
Arturo Zychlinsky ◽  
Edgardo Moreno
Keyword(s):  
Myeloid Differentiation ◽  
Toll Like Receptor ◽  
Immunostimulatory Activity ◽  
Toll Like Receptor 4 ◽  
Gram Negative ◽  
Macrophage Response ◽  
Tlr4 Activation ◽  
Myeloid Differentiation Factor ◽  
Kinetics Of

ABSTRACT It is not clear how the host initially recognizes and responds to infection by gram-negative pathogenic Brucella spp. It was previously shown (D. S. Weiss, B. Raupach, K. Takeda, S. Akira, and A. Zychlinsky, J. Immunol. 172:4463-4469, 2004) that the early macrophage response against gram-negative bacteria is mediated by Toll-like receptor 4 (TLR4), which signals in response to lipopolysaccharide (LPS). Brucella, however, has a noncanonical LPS which does not have potent immunostimulatory activity. We evaluated the kinetics of TLR4 activation and the cytokine response in murine macrophages after Brucella infection. We found that during infection of macrophages, Brucella avoids activation of TLR4 at 6 h but activates TLR4, TLR2, and myeloid differentiation factor 88 (MyD88) at 24 h postinfection. Interestingly, even though its activation is delayed, MyD88 is important for host defense against Brucella infection in vivo, since MyD88−/− mice do not clear the bacteria as efficiently as wild-type, TLR4−/−, TLR2−/−, or TLR4/TLR2−/− mice.

scholarly journals Toll-Like Receptor 4 Activation in Cancer Progression and Therapy

2011 ◽  
Vol 2011 ◽  
pp. 1-12 ◽  
Author(s):  
Alja Oblak ◽  
Roman Jerala
Keyword(s):  
Cancer Progression ◽  
Antitumor Immunity ◽  
Vaccine Adjuvants ◽  
Toll Like Receptor ◽  
Cancer Treatments ◽  
Toll Like Receptor 4 ◽  
Antitumor Vaccine ◽  
Tlr4 Activation ◽  
Opposing Effects ◽  
Intense Research

Cancer immunotherapy has been the focus of intense research since the late 19th century when Coley observed that bacterial components can contribute to cancer regression by eliciting an antitumor immune response. Successful activation and maturation of tumor-specific immune cells is now known to be mediated by bacterial endotoxin, which activates Toll-like receptor 4 (TLR4). TLR4 is expressed on a variety of immune as well as tumor cells, but its activation can have opposing effects. While TLR4 activation can promote antitumor immunity, it can also result in increased tumor growth and immunosuppression. Nevertheless, TLR4 engagement by endotoxin as well as by endogenous ligands represents notable contribution to the outcome of different cancer treatments, such as radiation or chemotherapy. Further research of the role and mechanisms of TLR4 activation in cancer may provide novel antitumor vaccine adjuvants as well as TLR4 inhibitors that could prevent inflammation-induced carcinogenesis.

Tanshinone IIA attenuates elastase-induced AAA in rats via inhibition of MyD88-dependent TLR-4 signaling

VASA ◽  
2014 ◽  
Vol 43 (1) ◽  
pp. 39-46 ◽  
Author(s):  
Tao Shang ◽  
Feng Ran ◽  
Qian Qiao ◽  
Zhao Liu ◽  
Chang-Jian Liu
Keyword(s):  
Nuclear Factor Κb ◽  
Tanshinone Iia ◽  
Myeloid Differentiation ◽  
Aortic Tissue ◽  
Toll Like Receptor ◽  
Sprague Dawley ◽  
Toll Like Receptor 4 ◽  
Tissue Samples ◽  
Myeloid Differentiation Factor ◽  
And Control

Background: The purpose of this study was to determine whether myeloid differentiation factor88-dependent Toll-Like Receptor-4 (TLR-4) signaling contributed to the inhibition of abdominal aortic aneurysm (AAA) by Tanshinone IIA (Tan IIA). Materials and methods: Male Sprague-Dawley rats (n = 12 / group) were randomly distributed into three groups: Tan IIA, control, and sham. The rats from Tan IIA and control groups under-went intra-aortic elastase perfusion to induce AAAs, and those in the sham group were perfused with saline. Only the Tan IIA group received Tan IIA (2 mg / rat / d). Aortic tissue samples were harvested at 24 d after perfusion and evaluated using reverse transcriptase-polymerase chain reaction, Western blot, immunohistochemistry and immunofluorescence. Results: The over-expression of Toll-Like Receptor-4 (TLR-4), Myeloid Differentiation factor 88 (MyD88), Phosphorylated Nuclear Factor κB (pNF-κB) and Phosphorylated IκBα (pIκBα) induced by elastase perfusion were significantly decreased by Tan IIA treatment. Conclusions: Tan IIA attenuates elastase-induced AAA in rats possibly via the inhibition of MyD88-dependent TLR-4 signaling, which may be one potential explanation of why Tan IIA inhibits AAA development through multiple effects.

Chelidonine Attenuates Sepsis-Induced Acute Lung Injury via Suppressing Toll-like Receptor 4/Myeloid Differentiation Factor 88/Nuclear Factor-॔B Signaling Pathway in Newborn Mice

2020 ◽  
Vol 19 (1) ◽  
pp. 120-126
Author(s):  
Ayinuerguli Adili ◽  
Adilijiang Kari ◽  
Chuanlong Song ◽  
Abulaiti Abuduhaer
Keyword(s):  
Acute Lung Injury ◽  
Lung Injury ◽  
Nuclear Factor Kappa B ◽  
Myeloid Differentiation ◽  
Nuclear Factor ◽  
Toll Like Receptor ◽  
Toll Like Receptor 4 ◽  
Inflammatory Infiltration ◽  
Newborn Mice ◽  
Myeloid Differentiation Factor

We have examined the mechanism underlying amelioration of sepsis-induced acute lung injury by chelidonine in newborn mice. To this end, a sepsis model was established using cecal ligation and puncture in newborn mice. The sepsis-induced acute lung injury was associated with an increased inflammatory infiltration and pulmonary congestion, as well as abnormal alveolar morphology. The lung injury-associated increased tumor necrosis factor-α and interleukin-1β in bronchoalveolar lavage fluid and lung, the markers of inflammatory infiltration and pulmonary congestion, diminished by chelidonine treatment. Chelidonine administration also downregulated protein levels of toll-like receptor 4, myeloid differentiation factor 88, phosphorylated nuclear factor-kappa B, and nuclear factor-kappa B that are elevated in response to sepsis. In conclusion, chelidonine provides a potential therapeutic strategy for newborn mice with acute lung injury.

scholarly journals Lycopene Inhibits Toll-Like Receptor 4-Mediated Expression of Inflammatory Cytokines in House Dust Mite-Stimulated Respiratory Epithelial Cells

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3127
Author(s):  
Jiyeon Choi ◽  
Joo Weon Lim ◽  
Hyeyoung Kim
Keyword(s):  
Epithelial Cells ◽  
A549 Cells ◽  
Cytokine Expression ◽  
Ros Production ◽  
Toll Like Receptor ◽  
Respiratory Epithelial Cells ◽  
Toll Like Receptor 4 ◽  
Mitochondrial Ros ◽  
Tlr4 Activation ◽  
Respiratory Epithelial

House dust mites (HDM) are critical factors in airway inflammation. They activate respiratory epithelial cells to produce reactive oxygen species (ROS) and activate Toll-like receptor 4 (TLR4). ROS induce the expression of inflammatory cytokines in respiratory epithelial cells. Lycopene is a potent antioxidant nutrient with anti-inflammatory activity. The present study aimed to investigate whether HDM induce intracellular and mitochondrial ROS production, TLR4 activation, and pro-inflammatory cytokine expression (IL-6 and IL-8) in respiratory epithelial A549 cells. Additionally, we examined whether lycopene inhibits HDM-induced alterations in A549 cells. The treatment of A549 cells with HDM activated TLR4, induced the expression of IL-6 and IL-8, and increased intracellular and mitochondrial ROS levels. TAK242, a TLR4 inhibitor, suppressed both HDM-induced ROS production and cytokine expression. Furthermore, lycopene inhibited the HDM-induced TLR4 activation and cytokine expression, along with reducing the intracellular and mitochondrial ROS levels in HDM-treated cells. These results collectively indicated that the HDM induced TLR4 activation and increased intracellular and mitochondrial ROS levels, thus resulting in the induction of cytokine expression in respiratory epithelial cells. The antioxidant lycopene could inhibit HDM-induced cytokine expression, possibly by suppressing TLR4 activation and reducing the intracellular and mitochondrial ROS levels in respiratory epithelial cells.

scholarly journals Biofilm Growth Increases Phosphorylcholine Content and Decreases Potency of Nontypeable Haemophilus influenzae Endotoxins

2006 ◽  
Vol 74 (3) ◽  
pp. 1828-1836 ◽  
Author(s):  
Shayla West-Barnette ◽  
Andrea Rockel ◽  
W. Edward Swords
Keyword(s):  
Haemophilus Influenzae ◽  
Inflammatory Responses ◽  
Opportunistic Pathogen ◽  
Host Responses ◽  
Toll Like Receptor ◽  
Nontypeable Haemophilus Influenzae ◽  
Toll Like Receptor 4 ◽  
Biofilm Growth ◽  
Bacterial Endotoxins ◽  
Cell Layers

ABSTRACT Nontypeable Haemophilus influenzae (NTHI) is a common respiratory commensal and opportunistic pathogen. NTHI is normally contained within the airways by host innate defenses that include recognition of bacterial endotoxins by Toll-like receptor 4 (TLR4). NTHI produces lipooligosaccharide (LOS) endotoxins which lack polymeric O side chains and which may contain host glycolipids. We recently showed that NTHI biofilms contain variants with sialylated LOS glycoforms that are essential to biofilm formation. In this study, we show that NTHI forms biofilms on epithelial cell layers. Confocal analysis revealed that sialylated variants were distributed throughout the biofilm, while variants expressing phosphorylcholine (PCho) were found within the biofilm. Consistent with this observation, PCho content of LOS purified from NTHI biofilms was increased compared to LOS from planktonic cultures. Hypothesizing that the observed changes in endotoxin composition could affect bioactivity, we compared inflammatory responses to NTHI LOS purified from biofilm and planktonic cultures. Our results show that endotoxins from biofilms induced weaker host innate responses. While we observed a minimal effect of sialylation on LOS bioactivity, there was a significant decrease in bioactivity associated with PCho substitutions. We thus conclude that biofilm growth increases the proportion of PCho+ variants in an NTHI population, resulting in a net decrease in LOS bioactivity. Thus, in addition to their well-documented resistance phenotypes, our data show that biofilm communities of NTHI bacteria contain variants that evoke less potent host responses.

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