scholarly journals Key Player in Cardiac Hypertrophy, Emphasizing the Role of Toll-Like Receptor 4

2020 ◽  
Vol 7 ◽  
Author(s):  
Zheng Xiao ◽  
Bin Kong ◽  
Hongjie Yang ◽  
Chang Dai ◽  
Jin Fang ◽  
...  
Keyword(s):  
Inflammatory Response ◽  
Cardiac Hypertrophy ◽  
Intracellular Signaling ◽  
Molecular Mechanisms ◽  
New Technologies ◽  
Immune Cell ◽  
Current Knowledge ◽  
Toll Like Receptor ◽  
Toll Like Receptor 4 ◽  
Tlr4 Signaling

Toll-like receptor 4 (TLR4), a key pattern recognition receptor, initiates the innate immune response and leads to chronic and acute inflammation. In the past decades, accumulating evidence has implicated TLR4-mediated inflammatory response in regulation of myocardium hypertrophic remodeling, indicating that regulation of the TLR4 signaling pathway may be an effective strategy for managing cardiac hypertrophy's pathophysiology. Given TLR4's significance, it is imperative to review the molecular mechanisms and roles underlying TLR4 signaling in cardiac hypertrophy. Here, we comprehensively review the current knowledge of TLR4-mediated inflammatory response and its interaction ligands and co-receptors, as well as activation of various intracellular signaling. We also describe the associated roles in promoting immune cell infiltration and inflammatory mediator secretion, that ultimately cause cardiac hypertrophy. Finally, we provide examples of some of the most promising drugs and new technologies that have the potential to attenuate TLR4-mediated inflammatory response and prevent or reverse the ominous cardiac hypertrophy outcomes.

scholarly journals Toll-Like Receptor 4 Is an Essential Upstream Regulator of On-Time Parturition and Perinatal Viability in Mice

Endocrinology ◽  
2015 ◽  
Vol 156 (10) ◽  
pp. 3828-3841 ◽  
Author(s):  
Hanan H. Wahid ◽  
Camilla L. Dorian ◽  
Peck Yin Chin ◽  
Mark R. Hutchinson ◽  
Kenner C. Rice ◽  
...  
Keyword(s):  
Inflammatory Response ◽  
Preterm Labor ◽  
Late Gestation ◽  
Gestation Length ◽  
Toll Like Receptor ◽  
Wild Type ◽  
Toll Like Receptor 4 ◽  
Tlr4 Signaling ◽  
Postterm Pregnancy ◽  
Upstream Regulator

An inflammatory response is instrumental in the physiological process of parturition but the upstream signals initiating inflammation are undefined. Because endogenous ligands for Toll-like receptor 4 (TLR4) are released in late gestation, we hypothesized that on-time labor requires TLR4 signaling, to trigger a cytokine and leukocyte response and accelerate the parturition cascade. In pregnant TLR4-deficient (Tlr4−/−) mice, average gestation length was extended by 13 hours and increased perinatal mortality was seen compared with wild-type controls. Quantification of cytokine and uterine activation gene expression showed that late gestation induction of Il1b, Il6, Il12b, and Tnf expression seen in control placenta and fetal membranes was disrupted in Tlr4−/− mice, and accompanied by a transient delay in expression of uterine activation genes, including prostaglandin F receptor, oxytocin receptor, and connexin-43. Leukocyte populations were altered before birth in TLR4-deficient females, with fewer neutrophils and macrophages in the placenta, and fewer dendritic cells and more regulatory T cells in the myometrium. Administration of TLR4 ligand lipopolysaccharide to pregnant wild-type mice induced cytokine expression and fetal loss, whereas Tlr4−/− pregnancies were protected. The small molecule TLR4 antagonist (+)-naloxone increased mean duration of gestation by 16 hours in wild-type mice. Collectively, these data demonstrate that TLR4 is a key upstream regulator of the inflammatory response acting to drive uterine activation and control the timing of labor. Because causal pathways for term and preterm labor converge with TLR4, interventions to manipulate TLR4 signaling may have therapeutic utility for women at risk of preterm labor, or in postterm pregnancy.

Toll-like receptor 4 in lymphatic endothelial cells contributes to LPS-induced lymphangiogenesis by chemotactic recruitment of macrophages

Blood ◽  
2009 ◽  
Vol 113 (11) ◽  
pp. 2605-2613 ◽  
Author(s):  
Shinae Kang ◽  
Seung-Pyo Lee ◽  
Kyung Eun Kim ◽  
Hak-Zoo Kim ◽  
Sylvie Mémet ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Lymphatic Vessel ◽  
Immune Cell ◽  
Lymphatic Vessels ◽  
Nuclear Factor Κb ◽  
Cell Trafficking ◽  
Lymphatic Endothelial Cells ◽  
Toll Like Receptor ◽  
Toll Like Receptor 4 ◽  
Tlr4 Signaling

The lymphatic vessel is a major conduit for immune cell transport; however, little is known about how lymphatic vessels regulate immune cell trafficking and how lymphatic vessels themselves respond to inflammation. Toll-like receptor 4 (TLR4) plays a central role in lipopolysaccharide (LPS)–induced inflammation, but the role of TLR4 in lymphatic endothelial cells (LECs) is poorly understood. Here, we found that LECs express high amounts of TLR4 in the intracellular region, and that the TLR4 of LECs is the main mediator of nuclear factor–κB (NF-κB) activation by LPS. LPS-TLR4 signaling in LECs resulted in the production of various chemokines for chemotaxis of macrophage. In addition, TLR4 in LECs actively contributed to the recruitment of macrophages to the draining lymphatic vessel. Furthermore, the macrophages that infiltrated into the lymphatic vessel induced lymphangiogenesis by secreting lymphangiogenic growth factors. These phenomena were largely attenuated not only in the mice defective in TLR4 signaling but also in the chimeric mice defective in TLR4 signaling that were recipients for bone marrow transplantation from normal TLR4-signaling mice. In conclusion, TLR4 in LECs plays an essential role in LPS-induced inflammatory lymphangiogenesis by chemotactic recruitment of macrophages.

scholarly journals CD4+CD25+Foxp3+ regulatory T cells regulate immune balance in unexplained recurrent spontaneous abortion via the Toll-like receptor 4/nuclear factor-κB pathway

2020 ◽  
Vol 48 (12) ◽  
pp. 030006052098094
Author(s):  
Shuang Qin ◽  
Li Li ◽  
Jia Liu ◽  
Jinrui Zhang ◽  
Qing Xiao ◽  
...  
Keyword(s):  
T Cells ◽  
Regulatory T Cells ◽  
Inflammatory Response ◽  
Mouse Model ◽  
Nuclear Factor Κb ◽  
Nuclear Factor ◽  
Toll Like Receptor ◽  
Toll Like Receptor 4 ◽  
Unexplained Recurrent Spontaneous Abortion ◽  
Tlr4 Antagonist

Objective The present study aimed to evaluate the effects of cluster of differentiation (CD)4+CD25+ forkhead box p3 (Foxp3)+ regulatory T cells (Tregs) on unexplained recurrent spontaneous abortion (URSA) and the associated mechanisms. Methods The proportion of CD4+CD25+Foxp3+ Tregs and inflammatory cytokine concentrations in the peripheral blood of women with URSA were measured by flow cytometry and enzyme-linked immunosorbent assay, respectively. CBA/JxDBA/2J mating was used to establish an abortion-prone mouse model and the model mice were treated with the Toll-like receptor 4 (TLR4) antagonist E5564 and the TLR4 agonist lipopolysaccharide. Results The proportion of CD4+CD25+Foxp3+ Tregs was decreased and the inflammatory response was increased in women with URSA. In the abortion-prone mouse model, E5564 significantly increased the proportion of CD4+CD25+Foxp3+ Tregs, decreased the inflammatory response, and increased Foxp3 mRNA and protein expression. Lipopolysaccharide had adverse effects on the abortion-prone model. Conclusions These data suggest that CD4+CD25+Foxp3+ Tregs regulate immune homeostasis in URSA via the TLR4/nuclear factor-κB pathway, and that the TLR4 antagonist E5564 may be a novel and potential drug for treating URSA.

Abstract 2874: Functional Polymorphisms in Toll-like Receptor 4 Predict Worse Outcome in Acute Ischemic Stroke Patients

Stroke ◽  
2012 ◽  
Vol 43 (suppl_1) ◽  
Author(s):  
Jonathan R Weinstein ◽  
Juliane Schulze ◽  
Richard V Lee ◽  
Dannielle Zierath ◽  
Patricia Tanzi ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Acute Ischemic Stroke ◽  
Immune Cell ◽  
Stroke Severity ◽  
Multiple Time ◽  
Toll Like Receptor ◽  
C Reactive Protein ◽  
Toll Like Receptor 4 ◽  
Reactive Protein ◽  
Functional Polymorphisms

Background: Toll-like receptor-4 (TLR4) plays a central role in the pathophysiology of acute ischemic stroke (AIS). Specific single nucleotide polymorphisms (SNPs) in TLR4 including 1063 A/G [Asp299Gly] and 1363 C/T [Thr399Ile] alter immune cell responsiveness to lipopolysaccharide (LPS) and are associated with increased rates of infection. The effect of these TLR4 SNPs on outcome following AIS is unknown. Methods: Patients were prospectively enrolled after onset of AIS. Clinical and demographic data were collected and neurological outcomes assessed at 3 months. Blood was drawn at multiple time points to quantify leukocyte subsets and assess plasma levels of C-reactive protein and a panel of cytokines. Genotyping for the TLR4 SNPs was also performed on blood samples. Uni- and multivariate analyses were performed to assess associations between TLR4 SNP haplotype and (i) each laboratory parameter noted above, (ii) infection risk and (iii) stroke outcome. Results: Of the 42 patients included; 6 (14%) were heterozygous for either one or both TLR4 SNPs. Baseline characteristics were similar in patients with or without a TLR4 SNP. In analyses adjusted for both initial stroke severity and age, the presence of a TLR4 SNP was associated with increases in blood leukocytes, plasma C-reactive protein and the cytokine interleukin-1 receptor antagonist (IL-1ra). The presence of either TLR4 SNP was also associated with a trend toward increased rates of infection (adjusted odds ratio and 95% confidence interval of 8.20 and 0.826-81.5, respectively) and a decreased likelihood of favorable outcome as defined by a modified Rankin Scale score of two or less at three months from stroke onset (0.014, 0.00-0.759). Conclusions: In AIS patients, functionally significant genetic variations in TLR4 influence both rates of stroke-associated infection and neurological outcome. These data suggest a direct connection between TLR4 function and stroke pathophysiology.

scholarly journals Toll-Like Receptor 4 Signaling and Drug Addiction

2020 ◽  
Vol 11 ◽  
Author(s):  
Ruyan Wu ◽  
Jun-Xu Li
Keyword(s):  
Drug Addiction ◽  
Multiple Drug ◽  
Toll Like Receptor ◽  
Toll Like Receptor 4 ◽  
Tlr4 Signaling ◽  
Drug Classes ◽  
Downstream Effectors ◽  
Potential Efficacy ◽  
Proinflammatory Responses

The emphasis of neuronal alterations and adaptations have long been the main focus of the studies of the mechanistic underpinnings of drug addiction. Recent studies have begun to appreciate the role of innate immune system, especially toll-like receptor 4 (TLR4) signaling in drug reward-associated behaviors and physiology. Drugs like opioids, alcohol and psychostimulants activate TLR4 signaling and subsequently induce proinflammatory responses, which in turn contributes to the development of drug addiction. Inhibition of TLR4 or its downstream effectors attenuated the reinforcing effects of opioids, alcohol and psychostimulants, and this effect is also involved in the withdrawal and relapse-like behaviors of different drug classes. However, conflicting results also argue that TLR4-related immune response may play a minimal part in drug addiction. This review discussed the preclinical evidence that whether TLR4 signaling is involved in multiple drug classes action and the possible mechanisms underlying this effect. Moreover, clinical studies which examined the potential efficacy of immune-base pharmacotherapies in treating drug addiction are also discussed.

scholarly journals Lycium barbarum Polysaccharides Promote Maturity of Murine Dendritic Cells through Toll-Like Receptor 4-Erk1/2-Blimp1 Signaling Pathway

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Xiangguo Duan ◽  
Yaru Lan ◽  
Xiaoyu Zhang ◽  
Shaozhang Hou ◽  
Jian Chen ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
Protein Expression ◽  
Molecular Mechanisms ◽  
Signal Molecules ◽  
Toll Like Receptor ◽  
Lycium Barbarum ◽  
Toll Like Receptor 4 ◽  
P38 Inhibitor ◽  
Mrna And Protein Expression ◽  
Lycium Barbarum Polysaccharides

In previous studies, Lycium barbarum polysaccharides (LBP), a traditional Chinese medicine, can promote immature dendritic cells (DCs) to mature. However, the molecular mechanisms by which LBP works are not yet elucidated. Here, we found that LBP can induce DCs maturation, which is mainly characterized by the upregulation of MHCII and costimulatory molecules (CD80, CD86), and increase the production of IL-6 and IL-4. Furthermore, we found that LBP could increase the mRNA and protein expression of TLR4, p38, Erk1/2, JNK, and Blimp1 signal molecules. More interestingly, after blocking by Toll-like receptor 4 inhibitor, Resatorvid (TAK 242), the mRNA and protein expression of TLR4, Erk1/2, and Blimp1 was significantly decreased while the expression of p38 and JNK has not changed. Then, we found that after blocking by p38 inhibitor (SB203580), Erk inhibitor (PD98059), and JNK inhibitor (SP603580) separately, Blimp1 protein expression was significantly reduced; after downregulating Blimp1 by Blimp1-siRNA, the production of IL-6 was reduced. In conclusion, our results indicate that LBP can induce maturation of DCs through the TLR4-Erk1/2-Blimp1 signal pathway instead of the JNK/p38-Blimp1 pathway. Our findings may provide a novel evidence for understanding the molecular mechanisms of LBP on activating murine DCs.

scholarly journals Deregulated immune cell recruitment orchestrated by FOXM1 impairs human diabetic wound healing

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Andrew P. Sawaya ◽  
Rivka C. Stone ◽  
Stephen R. Brooks ◽  
Irena Pastar ◽  
Ivan Jozic ◽  
...  
Keyword(s):  
Wound Healing ◽  
Inflammatory Response ◽  
Molecular Mechanisms ◽  
Immune Cell ◽  
Diabetic Mouse ◽  
Transcriptional Networks ◽  
Life Threatening ◽  
Diabetic Wound Healing ◽  
Diabetic Wounds

Abstract Diabetic foot ulcers (DFUs) are a life-threatening disease that often result in lower limb amputations and a shortened lifespan. However, molecular mechanisms contributing to the pathogenesis of DFUs remain poorly understood. We use next-generation sequencing to generate a human dataset of pathogenic DFUs to compare to transcriptional profiles of human skin and oral acute wounds, oral as a model of “ideal” adult tissue repair due to accelerated closure without scarring. Here we identify major transcriptional networks deregulated in DFUs that result in decreased neutrophils and macrophages recruitment and overall poorly controlled inflammatory response. Transcription factors FOXM1 and STAT3, which function to activate and promote survival of immune cells, are inhibited in DFUs. Moreover, inhibition of FOXM1 in diabetic mouse models (STZ-induced and db/db) results in delayed wound healing and decreased neutrophil and macrophage recruitment in diabetic wounds in vivo. Our data underscore the role of a perturbed, ineffective inflammatory response as a major contributor to the pathogenesis of DFUs, which is facilitated by FOXM1-mediated deregulation of recruitment of neutrophils and macrophages, revealing a potential therapeutic strategy.

scholarly journals Immunomodulatory Effects of Yersinia pestis Lipopolysaccharides on Human Macrophages

2009 ◽  
Vol 17 (1) ◽  
pp. 49-55 ◽  
Author(s):  
Motohiro Matsuura ◽  
Hideyuki Takahashi ◽  
Haruo Watanabe ◽  
Shinji Saito ◽  
Kazuyoshi Kawahara
Keyword(s):  
Inflammatory Response ◽  
Yersinia Pestis ◽  
Lipid A ◽  
Antagonistic Activity ◽  
Gram Negative Bacteria ◽  
Toll Like Receptor ◽  
Defense System ◽  
Toll Like Receptor 4 ◽  
Bacterial Binding ◽  
Binding Forms

ABSTRACTIn the current study, we investigated the activity of lipopolysaccharide (LPS) purified fromYersinia pestisgrown at either 27°C or 37°C (termed LPS-27 and LPS-37, respectively). LPS-27 containing hexa-acylated lipid A, similar to the LPS present in usual gram-negative bacteria, stimulated an inflammatory response in human U937 cells through Toll-like receptor 4 (TLR4). LPS-37, which did not contain hexa-acylated lipid A, exhibited strong antagonistic activity to the TLR4-mediated inflammatory response. The phagocytic activity in the cells was not affected by LPS-37. To estimate the activity of LPS in its bacterial binding form, formalin-killed bacteria (FKB) were prepared fromY. pestiscells grown at 27°C or 37°C (termed FKB-27 and FKB-37, respectively). FKB-27 strongly stimulated the inflammatory response. This activity was suppressed in the presence of an anti-TLR4 antibody but not an anti-TLR2 antibody. In addition, this activity was almost completely suppressed by LPS-37, indicating that the activity of FKB-27 is predominantly derived from the LPS-27 bacterial binding form. In contrast, FKB-37 showed no antagonistic activity. The results arising from the current study indicate thatY. pestiscauses infection in humans without stimulating the TLR4-based defense systemviabacterial binding of LPS-37, even when bacterial free LPS-37 is not released to suppress the defense system. This is in contrast to the findings for bacteria that possess agonistic LPS types, which are easily recognized by the defense systemviathe bacterial binding forms.

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