TAK-242 improves sepsis-associated acute kidney injury in rats by inhibiting the TLR4/NF-κB signaling pathway

OBJECTIVE

This study was designed to observe the effect of toll-like receptor 4 (TLR4)/nuclear factor kappa-B (NF-κB) pathway activity on sepsis-associated acute kidney injury (SA-AKI), thereby providing new considerations for the prevention and treatment of SA-AKI.

METHODS

The rats were divided into Sham, cecal ligation and puncture (CLP), CLP + vehicle, and CLP + TAK-242 groups. Except the Sham group, a model of CLP-induced sepsis was established in other groups. After 24 h, the indicators related to kidney injury in blood samples were detected. The pathological changes in the kidneys were observed by hematoxylin-eosin staining, and tubular damage was scored. Oxidative stress-related factors, mitochondrial dysfunction-related indicators in each group were measured; the levels of inflammatory factors in serum and kidney tissue of rats were examined. Finally, the expression of proteins related to the TLR4/NF-κB signaling pathway was observed by western blot.

RESULTS

Compared with the CLP + vehicle and CLP + TAK-242 groups, the CLP + TAK-242 group reduced blood urea nitrogen (BUN), creatinine (Cr), cystatin-C (Cys-C), reactive oxygen species (ROS), malondialdehyde (MDA), and inflammatory factors levels (p < 0.01), as well as increased superoxide dismutase (SOD) activity of CLP rats (p < 0.01). Additionally, TAK-242 treatment improved the condition of CLP rats that had glomerular and tubular injuries and mitochondrial disorders (p < 0.01). Further mechanism research revealed that TAK-242 can inhibit the TLR4/NF-κB signaling pathway activated by CLP (p < 0.01). Above indicators after TAK-242 treatment were close to those of the Sham group.

CONCLUSION

TAK-242 can improve oxidative stress, mitochondrial dysfunction, and inflammatory response by inhibiting the activity of TLR4/NF-κB signaling pathway, thereby preventing rats from SA-AKI.

TAK-242, a toll-like receptor 4 antagonist, against brain injury by alleviates autophagy and inflammation in rats

Inhibition of Toll-like receptor 4 (TLR4)-mediated inflammatory pathways exerts a critical effect on neuronal death; therefore, it is a possible new therapeutic approach for traumatic brain injury (TBI). Resatorvid (TAK-242) is a novel small-molecule compound widely used to inhibit TLR4-mediated pathways, but the protective mechanism of TAK-242 in TBI remains unclear. Herein, we analyzed the neuroprotective effects of TAK-242 in rats after TBI. The rat model of brain injury was established using a modified Free-fall device, and the rats were injected with TAK-242 (0.5 mg/kg) through the caudal vein before TBI. The rats were allocated into four groups: a sham group, a TBI group, a TBI + vehicle group, and a TBI + TAK-242 group. The brain tissue was extracted for histology and determination of the expression of autophagy-related proteins and inflammatory mediators. TAK-242 pretreatment significantly reduced the damage to hippocampal neurons. Neuronal autophagy increased after brain injury, whereas TAK-242 significantly reduced autophagy marker protein LC3-II in the hippocampus. In addition, TAK-242 pretreatment significantly downregulated NF-κB p65, TNF-α, and IL-1β in the hippocampus. In conclusion, TAK-242 significantly reduced hippocampal neuronal damage by inhibiting autophagy and neuroinflammatory activity, possibly via the NF-κB signaling pathway.

Inhibition of Toll-Like Receptor 4 Signaling Pathway Accelerates the Repair of Avascular Necrosis of Femoral Epiphysis through Regulating Macrophage Polarization in Perthes Disease

BACKGROUND

Legg-Calvé-Perthes disease (LCPD) is still a refractory disease in children's orthopedics. With the introduction of the concept of "osteoimmunology", the immune-inflammatory mechanisms between bone and immune system have become a research focus of LCPD. However, few studies have reported on the pathological role of inflammation-related receptors such as toll-like receptors (TLRs) as well as immune cells such as macrophages in LCPD. This study was for investigating the mechanism of TLR4 signaling pathway on the direction of macrophage polarization and the repair of avascular necrosis of femoral epiphysis in LCPD.

METHODS

With GSE57614 and GSE74089, differentially expressed genes were screened. Through enrichment analysis and protein-protein interaction network, the functions of TLR4 were explored. Furthermore, immunohistochemistry, enzyme-linked immunosorbent assay (ELISA), hematoxylin & eosin (H&E) staining, micro-CT, tartrate-resistant acid phosphatase (TRAP) dyeing and western blotting were performed for determining the influences of TAK-242 (a TLR4 inhibitor) on the repair of avascular necrosis of femoral epiphysis in rat models.

RESULTS

Totally 40 co-expression genes were screened as well as enriched in TLR4 signaling pathway. Immunohistochemistry and ELISA analyses certified that TLR4 facilitated macrophage polarization toward the M1 phenotype and prevented macrophage polarization toward the M2 phenotype. Besides, the results of H&E and TRAP staining, micro-CT, and western blotting showed that TAK-242 can inhibit osteoclastogenesis and promote osteogenesis.

CONCLUSION

Inhibition of TLR4 signaling pathway accelerated the repair of avascular necrosis of femoral epiphysis by regulating macrophage polarization in LCPD.

TAK-242 protects against oxygen-glucose deprivation and reoxygenation-induced injury in brain microvascular endothelial cells and alters the expression pattern of lncRNAs

Background

Deep hypothermic circulatory arrest (DHCA) is a technique used during the surgical treatment of aneurysms of the thoracic aorta in adult patients, and complex congenital heart disease in neonates. And brain microvascular endothelial cells (BMECs) are essential components of the cerebrovascular network and participate in maintaining the blood-brain barrier (BBB) and brain function. In our previous study, we found that oxygen-glucose deprivation and reoxygenation (OGD/R) activated Toll-like receptor 4 (TLR4) signaling in BMECs, and induced pyroptosis and inflammation. In this study, we further investigated the potential mechanism of ethyl(6R)-6-[N-(2-Chloro-4-fluorophenyl) sulfamoyl] cyclohex-1-ene-1-carboxylate (TAK-242) on BMECs under OGD/R, as in patients with sepsis, the TAK-242 was tested in clinical trials.

Methods

To confirm the function of TAK-242 on BMECs under OGD/R, cell viability, inflammatory factors, inflammation-associated pyroptosis, and nuclear factor-κB (NF-κB) signaling were determined using Cell Counting Kit-8 (CCK-8) assay, enzyme-linked immunosorbent assay (ELISA), and western blotting, respectively. To investigate the lncRNAs associated with TLR4 during OGD/R, long non-coding RNAs (lncRNAs) and messenger RNAs (mRNAs) expression patterns were profiled with RNA deep sequencing. Moreover, to confirm whether lncRNA-encoded short peptides, liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used.

Results

Relative control group, OGD/R inhibited the cell viability, increased the section of inflammatory factors secretion, including IL-1β, IL-6, and TNF-α, and promoted the pathways of TLR4/NLRP3/Caspase-1 and TLR4/NF-κB. However, TAK-242 + OGD/R group promoted OGD/R cell viability, decreased OGD/R-induced inflammatory factors secretion, and inhibited the pathways of TLR4/NLRP3/Caspase-1 and TLR4/NF-κB. In addition, AABR07000411.1, AABR070006957.1, and AABR070008256.1 were decreased in OGD/R cells compared with controls, but TAK-242 restored their expression under OGD/R condition. AABR07000473.1, AC130862.4, and LOC10254972.6 were induced by OGD/R, but were suppressed in TAK-242 + OGD/R cells compared with OGD/R. Moreover, AABR07049961.1, AC127076.2, AABR07066020.1, and AABR07025303.1-encoded short peptides were dysregulated in OGD/R cells, and TAK-242 attenuated the dysregulation of AABR07049961.1, AC127076.2, and AABR07066020.1-encoded short peptides.

Conclusions

TAK-242 alters the expression pattern of lncRNAs in OGD/R cells, and differently expressed lncRNAs may exert a protective effect against OGD/R injury through a mechanism of competing endogenous RNA (ceRNA) and encoding short peptides. These findings maybe provide a new theory basis for the treatment of DHCA.

Blocking toll-like receptor 4 mitigates static loading induced pro-inflammatory expression in intervertebral disc motion segments

While the anabolic effects of mechanical loading on the intervertebral disc (IVD) have been extensively studied, inflammatory responses to loading have not been as well characterized. Recent studies have highlighted a significant role of innate immune activation, particularly that of toll-like receptors (TLRs), in IVD degeneration. Biological responses of intervertebral disc cells to loading depend on many factors that include magnitude and frequency. The goals of this study were to characterize the inflammatory signaling changes in response to static and dynamic loading of IVD and investigate the contributions of TLR4 signaling in response to mechanical loading. Rat bone-disc-bone motion segments were loaded for 3 hr under a static load (20 % strain, 0 Hz) with or without an additional low-dynamic (4 % dynamic strain, 0.5 Hz) or high-dynamic (8 % dynamic strain, 3 Hz) strain, and results were compared to unloaded controls. Some samples were also loaded with or without TAK-242, an inhibitor of TLR4 signaling. The magnitude of NO release into the loading media (LM) was correlated with the applied frequency and strain magnitudes across different loading groups. Injurious loading profiles, such as static and high-dynamic, significantly increased Tlr4 and Hmgb1 expression while this result was not observed in the more physiologically relevant low-dynamic loading group. TAK-242 co-treatment decreased pro-inflammatory expression in static but not dynamic loaded groups, suggesting that TLR4 plays a direct role in mediating inflammatory responses of IVD to static compression. Overall, the microenvironment induced by dynamic loading diminished the protective effects of the TAK-242, suggesting that TLR4 plays a direct role in mediating inflammatory responses of IVD to static loading injury.

Influence of toll-like receptor-4 antagonist on bacterial load of asthma in Swiss albino mice: targeting TLR4/MD2 complex pathway

Air pollution and environmental issues significantly impact life, resulting in the emergence and exacerbation of allergic asthma and other chronic respiratory infections. The main objective of this study is to suppress allergic asthma by TAK-242 from lipopolysaccharide-induced airway inflammation primarily stimulating toll-like receptor-4, and also to determine the potential mechanism of asthma eradication. The TAK-242 anti-allergic action was assured through the ovalbumin murine model of asthma via bronchial hyperresponsiveness and inflammation of the respiration tract in a pre-existing allergic inflammation paradigm. Swiss albino mice were sensitized and then challenged by ovalbumin and lipopolysaccharide for 5 days straight. TAK-242 reaction was assessed by inflammatory cytokines, and inflammatory cell count was determined from blood serum and bronchoalveolar lavage fluid, as well as group-wise regular weight assessments. After ovalbumin, lipopolysaccharide infusion, toll-like receptor-4 agonists caused a substantial increase in airway hyperresponsiveness, specific cellular inflammation, histological alterations, and immune mediator synthesis, as well as dose-related body-weight variations. A decrease in lipopolysaccharide-induced leukocyte count and Th1/Th17 related cytokines, TNF-α, and IL-6 expression through the ELISA study was particularly noticeable. Finally in treated groups, TAK-242, a TLR4/MD2 complex inhibitor, reduced airway inflammation and histopathological changes, cytokine expression, and body-weight management. TAK-242 has been found in an ovalbumin allergic asthma model to be a potential inhibitor of lipopolysaccharide-induced respiratory infection.

Anti-inflammatory drugs prevent memory and hippocampal plasticity deficits following initial binge-like alcohol exposure in adolescent male rats

RATIONALE

Binge drinking during adolescence impairs learning and memory on the long term, and many studies suggest a role of neuroinflammation. However, whether neuroinflammation occurs after the very first exposures to alcohol remains unclear, while initial alcohol exposure impairs learning for several days in male rats.

OBJECTIVES

To investigate the role of neuroinflammation in the effects of only two binge-like episodes on learning and on neuronal plasticity in adolescent male rat hippocampus.

METHODS

Animals received two ethanol i.p. injections (3 g/kg) 9 h apart. Forty-eight hours later, we recorded long-term depression (LTD) and potentiation (LTP) in CA1 area of hippocampus slices. In isolated CA1, we measured immunolabelings for microglial activation and Toll-like receptor 4 (TLR4) and mRNA levels for several cytokines.

RESULTS

Forty-eight hours after the two binges, rats performed worse than control rats in novel object recognition, LTD was reduced, LTP was increased, and excitatory neurotransmission was more sensitive to an antagonist of the GluN2B subunit of the NMDA receptor. Exposure to ethanol with minocycline or indomethacin, two anti-inflammatory drugs, or with a TLR4 antagonist, prevented all effects of ethanol. Immunolabelings at 48 h showed a reduction of neuronal TLR4 that was prevented by minocycline pretreatment, while microglial reactivity was undetected and inflammatory cytokines mRNA levels were unchanged.

CONCLUSION

Two binge-like ethanol exposures during adolescence in rat involved neuroinflammation leading to changes in TLR4 expression and in GluN2B functioning inducing disturbances in synaptic plasticity and cognitive deficits. Anti-inflammatory drugs are good candidates to prevent brain function and memory deficits induced by few binge-drinking episodes.

Pharmacological inhibition of TLR4-NF-κB signaling by TAK-242 attenuates hydrocephalus after intraventricular hemorrhage

Compelling evidence has confirmed that inflammatory pathways involving TLR4-regulated cytokines and immune cells are vitallyimportant for the pathogenesis of posthemorrhagic hydrocephalus (PHH), hinting that pharmacological prevention of PHH is feasible. TAK-242, as a toll-like receptor 4 (TLR4) inhibitor, downregulates TLR4-induced inflammatory responses and becomes a potent and noveltherapeuticdrugcandidatefor PHH. In the present study, we investigate whether TAK-242 protects against hydrocephalus and improves the prognosis of intraventricular hemorrhage (IVH). We also explore the possible role of TAK-242 for the regulation of TLR4-NF-κB signaling pathway. A model of PHH was conducted in 6-week-old Male Sprague-Dawley (SD) rats. The rats were divided into four main groups, including the sham, IVH + vehicle, IVH + TAK-242 and IVH groups. Magnetic resonance imaging (MRI) was applied to measure the lateral ventricle volume. Western blot (WB) and immunofluorescence (IF) were applied to detect the expression of TLR4, NF-κB, fibronectin and laminin. A combined scoring system and Morris water maze were employed to evaluate neurological functions after IVH. We found that IVH induced heightened activation of TLR4-NF-κB signaling pathway. We observed the increased lateral ventricular volume, elevation of NF-κB in choroidplexus, as well as fibronectin and laminin in the subarachnoid space (SAS) and ventricular wall after IVH. Obviously, TAK-242 treatment effectively inhibited the up-regulation of NF-κB, fibronectin, laminin and significantly alleviated ventriculomegaly after IVH. Importantly, TAK-242 improved neurocognitive deficits after PHH. In conclusion, TAK-242 attenuated IVH-induced hydrocephalus and improved the prognosis of PHH. The underlying mechanism involved the TAK-242-mediated downregulation of TLR4-NF-κB signaling pathway.

Protective effect of Toll-like receptor 4 antagonist on inflammation, EEG, and memory changes following febrile seizure in Wistar rats

Neuroinflammation and fever are the main triggers in febrile seizures (FS). Focusing on inflammatory pathways and anti-inflammatory drugs could compensate for the limitations of existing medications. The aim of this study is to evaluate the neuroprotective effect of specific antagonizing Toll-like receptor 4 (TLR4), as a prominent inflammatory axis, on the consequences of FS and adulthood using animal models. Complex FS was induced on 9-11 day old male rat pups using a heated chamber. TAK-242, as a specific TLR4 inhibitor, was injected intraperitoneally before seizure induction. Seizure threshold, duration, and spike number were measured by electrocorticography. The levels of inflammatory cytokines, TLR4 protein expression, and oxidative stress markers were detected by enzyme-linked immunosorbent assay, western blotting, malondialdehyde (MDA), catalase (CAT), and superoxide dismutase (SOD) assessments in the cortex and hippocampus. Also, spatial and non-spatial memory were evaluated using the novel object recognition test (NORT) and double Y-maze test during adulthood. The results revealed that provoked inflammatory responses in neonate rats, after FS, were associated with the increase of the tumor necrosis factor alpha, interleukin-1β, and enhanced TLR4 protein expression. Meanwhile, based on performed behavioral tests, the inflammatory process was also involved in adulthood memory deficit. Pretreatment with TAK-242 reduced the inflammatory cytokines and TLR4 protein expression in the cortex and hippocampus of neonate rats and improvement in memory deficit in NORT and double Y-maze tasks. Also, pretreatment with TAK-242 elevated seizure threshold, SOD, and CAT activities, and decreased seizure duration and MDA level with no significant change in spike number. TAK-242 possibly controlled FS via inhibiting inflammation.

Effects of Toll-like receptor 4 inhibition on spatial memory and cell proliferation in male and female adult and aged mice

Toll-like receptors (TLRs) participate in the response to infection, stress, and injury by initiating an innate immune response. In addition, these receptors are expressed in many neural cell types and under physiological conditions are implicated in modulating cognitive function and neural plasticity in the adult and aged brain. Knockout of the Toll-like receptor 4 (TLR4) subtype enhances spatial memory and adult hippocampal neurogenesis through increasing proliferation and neuronal differentiation. Currently unknown is whether pharmacological inhibition of TLR4 produces similar enhancements in cognitive function and cell proliferation. The present study evaluated water maze performance, cytokine expression, and cell proliferation in the hippocampus of young and aged male and female C57BL6/J mice following treatment with the TLR4 antagonist, TAK-242. Further, alterations in the response to an acute stressor were evaluated in TAK-242-treated mice. Results showed that TAK-242 selectively enhanced spatial learning and memory in young females. Additionally, TAK-242 treatment reduced thigmotaxis in the water maze and lowered corticosterone levels following acute stress in females. TAK-242 decreased hippocampal interleukin (IL)-1β expression but had no effect on IL-6 or tumor necrosis factor-α (TNFα). Aged mice showed decreased cell proliferation compared to young mice, but TAK-242 administration had minimal effects on estimated Ki67 positive cell numbers. Findings indicate that pharmacological inhibition of TLR4 improves cognitive function in young females likely through attenuating stress reactivity.

TLR-4 targeting contributes to the recovery of osteoimmunology in periodontitis

OBJECTIVE

The aim of this study was to determine the potential role of TLR-4 in the osteoimmunological imbalance of periodontitis.

BACKGROUND

Although current evidence supports that TLR-4 plays an important role in the inflammatory response of periodontal tissues triggered by microorganisms, little information is available regarding the function of TLR-4 in the osteoimmune regulation of homeostasis in periodontitis.

METHODS

Human gingival epithelial cells (HGEC) were isolated from the gingival tissues of 3 healthy volunteers and the expression of osteoclastogenic cytokines was evaluated by ELISA and real time RT-PCR. In addition, 30 C57BL/6 mice were used and randomly divided into three groups: control group, periodontitis group (CP) and periodontitis+TAK-242 (a specific inhibitor of TLR-4) group (TAK-242) and the expression of osteoclastogenic cytokines and the osteoclast density in the periodontal tissue were evaluated by immunohistochemical staining and tartrate resistant acid phosphatase staining. Moreover, micro-computed tomography (Micro-CT) was used to assess bone resorption.

RESULTS

The in vitro results showed that TAK-242 blocked the overproduction of IL-1, IL-6, TNF-α and RANKL in HGEC treated with LPS. The in vivo results revealed that TAK-242 also effectively decreased these osteoclastogenic cytokines in periodontal tissue of mice with periodontitis. More importantly, Micro-CT analysis showed a significant reduction of the alveolar bone loss in the TAK-242 group compared with the CP group. Furthermore, the TRAP staining showed a significant lower density of osteoclasts in the alveolar bone area of the TAK-242 group.

CONCLUSION

TLR-4 inhibition decreased the differentiation of osteoclast through the inhibition of the overproduction of osteoclastogenic cytokines and the prevention of the alveolar bone absorption in mouse periodontitis models. Therefore, the use of TAK-242 might contribute to the recovery of the osteoimmunological homeostasis and might provide a potential strategy to treat periodontal diseases.

Inhibition of TLR4 Signaling Impedes Tumor Growth in Colitis-Associated Colon Cancer

Patients suffering from ulcerative colitis are at increased risk of developing colorectal cancer. Although the exact underlying mechanisms of inflammation-associated carcinogenesis remain unknown, the intestinal microbiota as well as pathogenic bacteria are discussed as contributors to inflammation and colitis-associated colon cancer (CAC). In the present study, we analyzed the impact of TLR4, the receptor for Gram-negative bacteria derived lipopolysaccharides, on intestinal inflammation and tumorigenesis in a murine model of CAC. During the inflammatory phases of CAC development, we observed a strong upregulation of Tlr4 expression in colonic tissues. Blocking of TLR4 signaling by a small-molecule-specific inhibitor during the inflammatory phases of CAC strongly diminished the development and progression of colonic tumors, which was accompanied by decreased numbers of infiltrating macrophages and reduced colonic pro-inflammatory cytokine levels compared to CAC control mice. Interestingly, inhibiting bacterial signaling by antibiotic treatment during the inflammatory phases of CAC also protected mice from severe intestinal inflammation and almost completely prevented tumor growth. Nevertheless, application of antibiotics involved rapid and severe body weight loss and might have unwanted side effects. Our results indicate that bacterial activation of TLR4 on innate immune cells in the colon triggers inflammation and promotes tumor growth. Thus, the inhibition of the TLR4 signaling during intestinal inflammation might be a novel approach to impede CAC development.

TAK-242 ameliorates olfactory dysfunction in a mouse model of allergic rhinitis by inhibiting neuroinflammation in the olfactory bulb

OBJECTIVE

Olfactory dysfunction (OD) is a common symptom of allergic rhinitis (AR) that can seriously affect patient quality of life; however, the associated pathogenesis remains unclear. This study aimed to explore the relationship between OD and damage of the olfactory bulb (OB) in allergic rhinitis (AR). The therapeutic potential of TAK-242, a selective TLR4 inhibitor, was evaluated for OD.

METHOD

An AR mouse model was established with ovalbumin (OVA) to test the olfactory function of AR mice using the buried food pellet test (BFPT). Mice with OD were intraperitoneally injected with TAK-242 or 1% DMSO (vehicle). Immunohistochemistry was used to detect microglia and astrocyte activation in the OB. TUNNEL staining was performed to detect apoptosis in the OB. Proteins in the TLR4 signaling pathway were detected by Western blot. The level of proinflammatory factor mRNA in the OB was determined by RT-PCR.

RESULT

Neuroinflammation was observed in the OB of the OD group, as evidenced by glial cell activation and increased proinflammatory factor expression. The number of apoptotic cells was significantly increased in the OB of the OD group. The expression of TLR4, MyD88, and p-NF-κBp65 was significantly up-regulated in the OB of the OD group. TAK-242 treatment significantly reduced the level of IL-1β, IL-6, and TNF-α mRNA expression, as well as activation of microglia and astrocytes in the OB tissues.

CONCLUSION

TAK-242 improve olfactory function in AR mice mainly by reducing neuroinflammation and apoptosis in the OB, which may be related to blocking the TLR4/MyD88/NF-κB signaling pathway.

Toll-like receptor 4 signaling pathway is correlated with pathophysiological characteristics of AML patients and its inhibition using TAK-242 suppresses AML cell proliferation

PURPOSE

Acute myeloid leukemia (AML) is one of the most severe blood cancers. Many studies have revealed that inflammation has an essential role in the progression of hematopoietic malignancies. Since the toll-like receptor 4 (TLR4) pathway, an important pathway involved in inflammation induction, has previously been associated with solid tumors, we hypothesized that it would be correlated with the pathophysiological characteristics of AML patients and could be considered as an anticancer target.

METHOD

We evaluated the mRNA expression of TLR4, MyD88, RelB, and NF-кB using qRT-PCR in bone-marrow samples of 40 AML patients categorized into four groups according to prognosis, cell type, age, and drug response. Next, we explored the expression of these genes in three AML cell lines (NB4, U937, and KG-1) and used TAK-242, a specific inhibitor of TLR4, to investigate whether this inhibition could suppress AML cell proliferation using cell-cycle analysis. The effect of TAK-242 on arsenic trioxide (ATO) cytotoxicity was also assessed.

RESULT

The results of qRT-PCR showed that most genes had higher expression in patients with poor prognosis or drug-resistant statues. They were also overexpressed in patients with less-differentiated cells. Moreover, TAK-242 inhibited cell proliferation of all the cell lines and altered their cell cycle distribution. It could also intensify the cytotoxicity of ATO in combination therapy.

CONCLUSION

In sum, the TLR4 pathway was related to pathophysiological characteristics of AML and its inhibition using TAK-242 could be considered as a promising treatment strategy in the TLR4 expressing AML cells, individually or in combination with ATO.

Toll-like Receptor 4 Inhibitor TAK-242 Improves Fulminant Hepatitis by Regulating Accumulation of Myeloid-Derived Suppressor Cell

Fulminant hepatitis (FH) is an acute clinical disease with a poor prognosis and high mortality rate. The purpose of this study was to determine the protective effect of the Toll-like receptor 4 (TLR4) inhibitor TAK-242 on lipopolysaccharide (LPS)/D-galactosamine (D-GalN)-induced explosive hepatitis and explore in vivo and in vitro mechanisms. Mice were pretreated with TAK-242 for 3 h prior to LPS (10 μg/kg)/D-GalN (250 mg/kg) administration. Compared to the LPS/D-GalN group, the TAK-242 pretreatment group showed significantly prolonged survival, reduced serum alanine aminotransferase and aspartate aminotransferase levels, relieved oxidative stress, and reduced inflammatory interleukin (IL)-6, IL-12, and tumor necrosis factor-α levels. In addition, TAK-242 increased the accumulation of myeloid-derived suppressor cells (MDSCs). Next, mice were treated with an anti-Gr-1 antibody to deplete MDSCs, and adoptive transfer experiments were performed. We found that TAK-242 protected against FH by regulating MDSCs. In the in vitro studies, TAK-242 regulated the accumulation of MDSCs and promoted the release of immunosuppressive inflammatory cytokines. In addition, TAK-242 inhibited protein expression of nuclear factor-κB and mitogen-activated protein kinases. In summary, TAK-242 had a hepatoprotective effect against LPS/D-GalN-induced explosive hepatitis in mice. Its protective effect may be involved in suppressing inflammation, reducing oxidative stress, and increasing the proportion of MDSCs.

TAK-242 Attenuates Crush Injury Induced Acute Kidney Injury through Inhibiting TLR4/NF-κB Signaling Pathways in Rats

BACKGROUND

To investigate if toll-like receptor (TLR) 4/nuclear factor-kappa B (NF-κB) signaling pathways mediated crush injury induced acute kidney injury (AKI) in rats, and if TAK-242 (a specific inhibitor of TLR4) attenuates the injury through inhibiting the signaling pathways.

METHODS

This study was divided into two parts: (1) Establish the crush injury model: 50 rats were randomly divided into control group and four crush injury groups (n = 10/group). Crush injury groups were given 3kg pressure for eight hours and were sacrificed at the time points of 0h, 6h, 12h, and 24h after relieving pressure. And (2) Select the most obvious injury group (12h group) for drug intervention group. Thirty rats were randomly divided into control group, 12h group, and 12h+TAK-242 group (n = 10/group). Two parts detection were as follows: pathological changes of kidney tissues were observed in Haematoxylin and Eosin (HE) staining. Serum creatinine, blood urea nitrogen (BUN), myoglobin (Mb), and blood potassium were examined by automatic biochemical analysis instrument. Interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) were measured by enzyme-linked immunosorbent assay (ELISA). The TLR4 messenger ribonucleic acid (mRNA), TLR4, and P65 were detected by real-time polymerase chain reaction (PCR), western blot, immunohistochemistry staining.

RESULTS

Compared with the control group, kidney tissues were damaged in crush injury groups, and most obvious in the 12h group. The level of serum creatinine, BUN, Mb, blood potassium, IL-6, TNF-α, and TLR4mRNA were increased in the crush injury groups and significantly increased in the 12h group (P <.05). The TLR4 and P65 were significantly increased in the 12h group (P <.05). Compared with the 12h group, kidney tissue damage was significantly reduced in the TAK-242 group (P <.05). The level of serum creatinine, BUN, Mb, blood potassium, IL-6, TNF-α, TLR4mRNA, TLR4, and P65 in the TAK-242 group were significantly reduced (P <.05).

CONCLUSION

The present findings conclude that TLR4/NF-κB signaling pathways mediated crush injury induced AKI in rats, and TAK-242 attenuates the injury through inhibiting the signaling pathways.

TAK-242 ameliorates DSS-induced colitis by regulating the gut microbiota and the JAK2/STAT3 signaling pathway

Background

The goal of the present study was to investigate the effects of TAK-242 on the gut microbiota and the TLR4/JAK2/STAT3 signaling pathway in mice with dextran sulfate sodium (DSS)-induced colitis.

Results

At the phylum level, Bacteroidetes, Firmicutes, Actinobacteria, Cyanobacteria, Epsilonbacteraeota and Proteobacteria were the primary microbiota in the five groups. TAK-242 treatment significantly enhanced Verrucomicrobia and Actinobacteria; significantly decreased Cyanobacteria, Epsilonbacteraeota and Proteobacteria; and particularly promoted the growth of Akkermansia. TAK-242 markedly alleviated DSS-induced colitis symptoms and colonic lesions by promoting IL-10 release, inhibiting IL-17 release, downregulating TLR4 and JAK2/STAT3 mRNA and protein expression and increasing JAK2/STAT3 phosphorylation.

Conclusion

TAK-242 modulates the structure of the gut microbiota in colitis and may be a novel therapeutic candidate for ulcerative colitis.

Resatorvid protects against hypoxic-ischemic brain damage in neonatal rats

Secondary brain damage caused by hyperactivation of autophagy and inflammatory responses in neurons plays an important role in hypoxic-ischemic brain damage (HIBD). Although previous studies have implicated Toll-like receptor 4 (TLR4) and nuclear factor kappa-B (NF-κB) in the neuroinflammatory response elicited by brain injury, the role and mechanisms of the TLR4-mediated autophagy signaling pathway in neonatal HIBD are still unclear. We hypothesized that this pathway can regulate brain damage by modulating neuron autophagy and neuroinflammation in neonatal rats with HIBD. Hence, we established a neonatal HIBD rat model using the Rice-Vannucci method, and injected 0.75, 1.5, or 3 mg/kg of the TLR4 inhibitor resatorvid (TAK-242) 30 minutes after hypoxic ischemia. Our results indicate that administering TAK-242 to neonatal rats after HIBD could significantly reduce the infarct volume and the extent of cerebral edema, alleviate neuronal damage and neurobehavioral impairment, and decrease the expression levels of TLR4, phospho-NF-κB p65, Beclin-1, microtubule-associated protein l light chain 3, tumor necrosis factor-α, and interleukin-1β in the hippocampus. Thus, TAK-242 appears to exert a neuroprotective effect after HIBD by inhibiting activation of autophagy and the release of inflammatory cytokines via inhibition of the TLR4/NF-κB signaling pathway. This study was approved by the Laboratory Animal Ethics Committee of Affiliated Hospital of Yangzhou University, China (approval No. 20180114-15) on January 14, 2018.

Inhibitive effect of TAK-242 on Tenon's capsule fibroblasts proliferation in rat eyes

AIM

To study the inhibition effect of TAK-242 on the proliferation of rat eye Tenon's capsule fibroblasts via the toll-like receptor 4 (TLR4) signaling pathway.

METHODS

SD rat Tenon's capsule fibroblasts were extracted and cultured, then the cells were divided into normal control group, lipopolysaccharide (LPS) group (10 g/mL LPS) and TAK-242 group (1 µmol/L TAK-242, and 10 µg/mL LPS after 30min). The expressions of TLR4, transforming growth factor-β1 (TGF-β1) and interleukin-6 (IL-6) in each group were detected by Western blot and reverse transcriptase-polymerase chain reaction (RT-PCR). Cell proliferation was detected by cell counting kit-8 (CCK-8).

RESULTS

Double immunofluorescent labeling in the extracted cells showed negative keratin staining and positive vimentin staining. Western blot showed that the LPS group had the highest expression of TLR4 and TGF-β1 (P<0.01). Enzyme linked immunosorbent assay (ELISA) also showed that the secretion of IL-6 was the highest in LPS group (P<0.01). But there was no significant difference in TLR4 and TGF-1, as well as IL-6 expressions between the TAK-242 group and the normal control group (P>0.05). RT-PCR showed that the IL-6 mRNA expression in LPS group was the highest in the three groups (P<0.01).

CONCLUSION

TAK-242 inhibits the proliferation of LPS-induced Tenon's capsule fibroblasts and the release of inflammatory factors by regulating the TLR4 signaling pathway, providing a new idea for reducing the scarring of the filter passage after glaucoma filtration surgery.

TLR4 antagonist ameliorates combined allergic rhinitis and asthma syndrome (CARAS) by reducing inflammatory monocytes infiltration in mice model

The present study aims to investigate the effects of toll-like receptor 4 (TLR4) antagonist in an ovalbumin (OVA)-induced mouse model of combined allergic rhinitis and asthma syndrome (CARAS). An OVA-induced mouse model of CARAS was established and TLR4 antagonist, TAK-242, was administrated intranasally or intraperitoneally. The number of sneezing and nasal rubbing was counted. The frequency of different cell types in the bronchoalveolar lavage fluid (BALF) and nasal lavage fluid (NLF) was analyzed using flow cytometry. Expressions of protein in nasal mucosa and lungs were determined using western blotting. Levels of interleukin (IL)-4, IL-5, and IL-13 were determined using Enzyme-linked Immunosorbent Assay (ELISA). Histological scores were applied for the assessment of lung injury. Treatment of TAK-242 downregulated CCL2 expression and reduced monocyte infiltration in nasal mucosa and lung tissues. Additionally, treatment of TAK-242 ameliorated upper airway symptoms including the sneezing and nasal rubbing by the regulation of cytokines including IL-4, IL-5, and IL-13. Furthermore, treatment of TAK-242 ameliorated lower airway symptoms including decreasing the frequency of CD45⁺SiglecF⁺CD11b⁺CD11c^- eosinophils in BALF and IL13⁺ Th2 cells in the lungs. In conclusion, treatment of TAK-242 ameliorated CARAS-related lung injury by inhibiting lymphocyte infiltration, reducing monocytes infiltration, as well as regulating the frequency of eosinophils and Th2 cells.

Low back pain and disc degeneration are decreased following chronic toll-like receptor 4 inhibition in a mouse model

OBJECTIVE

Intervertebral disc degeneration is a leading cause of chronic low back pain (LBP) but current treatment is limited. Toll-like receptors (TLRs) on disc cells are activated by endogenous extracellular matrix (ECM) fragments and modulate degeneration in vitro. This study investigated whether inhibiting TLR4 slows disc degeneration and reduces behavioral signs of LBP in vivo.

DESIGN

7-9-month old wild-type and secreted protein acidic and rich in cysteine (SPARC)-null (a model of disc degeneration and LBP) male mice were treated with TAK-242 (TLR4 inhibitor) once, and following a 10-day washout, mice were treated 3 times/week for 8 weeks. Behavioral signs of axial discomfort and radiating leg pain were assessed weekly with the grip force assay and acetone test, respectively. Following treatment, pain-related spinal cord changes were evaluated and lumbar discs were excised and cultured. Cytokine secretion from discs was evaluated with protein arrays.

RESULTS

SPARC-null mice displayed elevated signs of axial and radiating pain at baseline compared to wild-type. Chronic, but not acute, TLR4 inhibition reduced behavioral signs of pain compared to vehicle. SPARC-null mice have increased calcitonin gene-related peptide (CGRP)- and glial fibrillary acidic protein (GFAP)-immunoreactivity (astrocyte marker) in the dorsal horn compared to wild-type, which is reduced by chronic TLR4 inhibition. Ex vivo degenerating discs from SPARC-null mice secrete increased levels of many pro-inflammatory cytokines, which chronic TLR4 inhibition reduced.

CONCLUSION

Chronic TLR4 inhibition decreased behavioral signs of LBP, pain-related neuroplasticity and disc inflammation in SPARC-null mice. TAK-242 inhibits TLR4 activation within discs, as evidenced by decreases in cytokine release. Therefore, TLRs are potential therapeutic targets to slow disc degeneration and reduce pain.

Porphyromonas gingivalis lipopolysaccharide induces over production of CC chemokine ligand 2 via toll-like receptor-4 in oral lichen planus

BACKGROUND

We recently reported that the CC chemokine ligand 2 (CCL2)-CC receptor 2 (CCR2) axis was involved in the pathogenesis of oral lichen planus (OLP). However, the exact mechanism for the high expression of CCL2 in OLP specimens is not clear. Therefore, this study was designed to investigate the potential role of the toll-like receptor 4 (TLR-4) pathway in overproduction of CCL2 in OLP lesions.

METHODS

Immunohistochemical staining and real-time RT-PCR were used to detect TLR-4, CCL2, and CCR2 expression in OLP lesions. Then, gingival epithelial cells from OLP lesions were established and treated with Porphyromonas gingivalis (P. gingivalis) lipopolysaccharide (LPS). CCL2 expression in epithelial cells was determined by Western blotting and real-time RT-PCR. In some experiments, TAK-242, a specific inhibitor of TLR-4, was used to block the TLR-4 pathway before cells were stimulated with LPS.

RESULTS

We found that TLR-4 was significantly increased in the epithelium of OLP specimens, compared with controls. Moreover, LPS can induce the over production of CCL2 in epithelial cells of OLP, in vitro. TAK-242 effectively eliminated the increase in CCL2 expression induced by LPS by blocking the TLR-4/NF-κB pathway. In addition, we again confirmed that expression of CCL2 and CCR2 was increased in OLP specimens.

CONCLUSION

Increased TLR-4 expression contributes to the upregulated expression of CCL2 in the epithelium of OLP lesions, which suggests that oral bacteria participate in the pathogenesis of OLP via the TLR-4 pathway.

Toll-Like Receptor-4 Inhibitor TAK-242 Attenuates Motor Dysfunction and Spinal Cord Pathology in an Amyotrophic Lateral Sclerosis Mouse Model

Neuroinflammation contributes to amyotrophic lateral sclerosis (ALS) progression. TLR4, a transmembrane protein that plays a central role in activation of the innate immune system, has been shown to induce microglial activation in ALS models. TLR4 is up-regulated in the spinal cords of hSOD1^G93A mice. We aimed to examine the effects of specific TLR4 inhibition on disease progression and survival in the hSOD1^G93A mouse model of ALS. Immunologic effect of TLR4 inhibition in vitro was measured by the effect of TAK-242 treatment on LPS-induced splenocytes proliferation. hSOD1^G93A transgenic mice were treated with TAK-242, a selective TLR4 inhibitor, or vehicle. Survival, body weight, and motor behavior were monitored. To evaluate in vivo immunologic modifications associated with TAK-242 treatment, we measured serum IL-1β in the plasma, as well as IL-1β and TNF-α mRNAs in the spinal cord in wild-type mice and in TAK-242-treated and vehicle-treated early symptomatic hSOD1^G93A mice. Immunohistochemical analysis of motor neurons, astrocytes, and microglial reactivity in the spinal cords were performed on symptomatic (100 days old) TAK-242-treated and vehicle-treated hSOD1^G93A mice. In vitro, splenocytes taken from 100 days old hSOD1^G93A mice showed significantly increased proliferation when exposed to LPS (p = 0.0002), a phenomenon that was reduced by TAK-242 (p = 0.0179). TAK-242 treatment did not attenuate body weight loss or significantly affect survival. However, TAK-242-treated hSOD1^G93A mice showed temporary clinical delay in disease progression evident in the ladder test and hindlimb reflex measurements. Plasma IL-1β levels were significantly reduced in TAK-242-treated compared to vehicle-treated hSOD1^G93A mice (p = 0.0023). TAK-242 treatment reduced spinal cord astrogliosis and microglial activation and significantly attenuated spinal cord motor neuron loss at early disease stage (p = 0.0259). Compared to wild-type animals, both IL-1β and TNF-α mRNAs were significantly upregulated in the spinal cords of hSOD1^G93A mice. Spinal cord analysis in TAK-242-treated hSOD1^G93A mice revealed significant attenuation of TNF-α mRNA (p = 0.0431), but no change in IL-1β mRNA. TLR4 inhibition delayed disease progression, attenuated spinal cord astroglial and microglial reaction, and reduced spinal motor neuron loss in the ALS hSOD1^G93A mouse model. However, this effect did not result in increased survival. To our knowledge, this is the first report on TAK-242 treatment in a neurodegenerative disease model. Further studies are warranted to assess TLR4 as a therapeutic target in ALS.

Toll-like receptor 4 inhibitor protects against retinal ganglion cell damage induced by optic nerve crush in mice

Toll-like receptor 4 (TLR4) plays key roles in innate immune responses and inflammatory reactions. TAK-242 (resatorvid) is a small-molecule cyclohexene derivative that selectively inhibits TLR4 signaling pathways and suppresses inflammatory reactions. Here we investigated the protective effects of TAK-242 against optic nerve crush (ONC) which induces axonal injury like glaucoma in mice. TAK-242 was injected intravitreally immediately after ONC. The effect of TAK-242 was evaluated by measuring the number of fluorogold-labeled retinal ganglion cells (RGCs) at 10 days after ONC. Furthermore, the expression levels of phosphorylated-nuclear factor-kappa B (p-NF-κB) and phosphorylated-p38 (p-p38) were measured by Western blotting. In addition, we examined activated astrocytes by immunostaining. TAK-242 significantly abrogated the loss of RGCs associated with ONC. Moreover, the expression levels of p-NF-κB and p-p38 were significantly reduced by TAK-242 treatment. Furthermore, TAK-242 and C34, a TLR4 inhibitor, significantly reduced astrocyte activation in the ganglion cell and inner plexiform layers, compared with vehicle treatment. These findings indicate that TAK-242 inhibits not only the TLR4 signaling pathway but also astrocyte activation downstream of this pathway, suggesting that the inhibition of TLR4 signaling is a promising candidate for the treatment of glaucoma.

Systemic TAK-242 prevents intrathecal LPS evoked hyperalgesia in male, but not female mice and prevents delayed allodynia following intraplantar formalin in both male and female mice: The role of TLR4 in the evolution of a persistent pain state

OBJECTIVE

Pain resulting from local tissue injury or inflammation typically resolves with time. Frequently, however, this pain may unexpectedly persist, becoming a pathological chronic state. Increasingly, the innate and adaptive immune systems are being implicated in the initiation and maintenance of these persistent conditions. In particular, Toll-like receptor 4 (TLR4) signaling has been shown to mediate the transition to a persistent pain state in a sex-dependent manner. In the present work, we explored this contribution using the TLR4 antagonist, TAK-242.

METHODS

Male and female C57Bl/6 mice were given intravenous (IV), intrathecal (IT), or intraperitoneal (IP) TAK-242 prior to IT delivery of lipopolysaccharide (LPS), and tactile reactivity was assessed at regular intervals over 72-h. Additional groups of mice were treated with IP TAK-242 prior to intraplantar formalin, and flinching was monitored for 1-h. Tactile reactivity was assessed at 7-days after formalin delivery.

RESULTS

LPS evoked TNF release from male and female macrophages and RAW267.4 cells, which was blocked in a concentration dependent fashion by TAK-242. In vivo, IT LPS evoked tactile allodynia to a greater degree in male than female mice. TAK-242, given by all routes, prevented development of IT LPS-induced tactile allodynia in male animals, but did not reverse their established allodynia. TLR4 deficiency and TAK-242 treatment attenuated IT LPS-induced allodynia in male, but not female mice. In the formalin model, pre-treatment with TAK-242 did not affect Phase 1 or Phase 2 flinching, but prevented the delayed tactile allodynia in both male and unexpectedly in female mice (Phase 3).

CONCLUSIONS

Together, these results suggest that TAK-242 is a TLR4 antagonist that has efficacy after systemic and intrathecal delivery and confirms the role of endogenous TLR4 signaling in triggering the development of a delayed allodynia in both male and female mice.

Analgesic effect of TAK-242 on neuropathic pain in rats

BACKGROUND

The current study investigated the analgesic effect of the Toll-like receptor 4 (TLR4) specific antagonist TAK-242 on neuropathic pain in rats and its underlying mechanism.

METHODS

A total of 132 adult Sprague-Dawley (SD) rats were randomly divided into four groups: the sham operation group, the neuropathic pain model group, the TAK-242 low-dose treatment group, and the TAK-242 high-dose treatment group. The heat pain and mechanic pain thresholds of rats were detected on preoperative day 1 and postoperative days 1, 3, 7, and 10. The expression levels of IκBα, p65, IL-1β, and TNF-α in the spinal cord dorsal horn were detected on postoperative day 7 in one group of rats.

RESULTS

Compared with rats in the sham operation group, the heat pain and mechanic pain thresholds of the rats in the neuropathic pain model group significantly decreased; their expression levels of p65, IL-1β, and TNF-α significantly increased; and their expression level of IkBα significantly decreased. Compared with the neuropathic pain group, high doses of TAK-242 significantly inhibited the expression of p65, IL-1β, and TNF-α; significantly increased the expression level of IkBα; and upregulated the heat pain and mechanic pain thresholds.

CONCLUSION

TAK-242 might improve neuropathic pain through downregulation of the NF-κB pathway.

Inhibition of Toll-like receptor 4 suppresses liver injury induced by biliary obstruction and subsequent intraportal lipopolysaccharide injection

The objective of this study was to elucidate the role of Toll-like receptor 4 (TLR4) in liver injury induced by biliary obstruction and subsequent intraportal lipopolysaccharide (LPS) infusion in rats. Biliary obstruction often leads to the development of bacterial translocation. Rats were subjected to either a sham operation (Sham group) or bile duct ligation for 7 days (BDL group). Seven days after each operation, LPS (0.5 μg) was injected through the ileocecal vein. In other experiments, rats that had undergone BDL were pretreated, before LPS challenge, with internal biliary drainage (Drainage group); intravenous TAK-242, a TLR4 inhibitor (TAK group); or intravenous GdCl3, a Kupffer cell deactivator (GdCl3 group). The expression of the TLR4 protein and the number of Kupffer cells in the liver were significantly increased in the BDL group compared with the Sham group. These changes were normalized after biliary drainage. The expression of TLR4 colocalized with Kupffer cells, which was confirmed by double immunostaining. Serum levels of liver enzymes and proinflammatory cytokines after intraportal LPS injection were significantly higher in the BDL group than in the Sham group. However, pretreatment with TAK-242 or GdCl3 strongly attenuated these changes to levels similar to those seen with biliary drainage. These results imply that blocking TLR4 signaling effectively attenuates liver damage to the same level as that observed with biliary drainage in rats with BDL and subsequent intraportal LPS infusion. TAK-242 treatment may be used for patients who are susceptible to liver damage by biliary obstruction and endotoxemia.