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BACKGROUND: Alzheimer's disease (AD) affects approximately 50 million people globally and is expected to triple by 2050. Arctiin is a lignan found in the Arctium lappa L. plant. Arctiin possesses anti-proliferative, antioxidative and anti-adipogenic. OBJECTIVES: We aimed to explore the potential therapeutic effects of Arctiin on rats with AD by evaluating the expression of TLR4, NLRP3, STAT3, TGF-ß, cyclin D1, and CDK2. METHODS: AD was induced in rats by administering 70 mg/kg of aluminum chloride through intraperitoneal injection daily for six weeks. After inducing AD, some rats were treated with 25 mg/kg of Arctiin daily for three weeks through oral gavage. Furthermore, to examine the brain tissue structure, hippocampal sections were stained with hematoxylin/eosin and anti-TLR4 antibodies. The collected samples were analyzed for gene expression and protein levels of TLR4, NLRP3, STAT3, TGF-ß, cyclin D1, and CDK2. RESULTS: In behavioral tests, rats showed a significant improvement in their behavior when treated with Arctiin. Microimages stained with hematoxylin/eosin showed that Arctiin helped to improve the structure and cohesion of the hippocampus, which was previously impaired by AD. Furthermore, Arctiin reduced the expression of TLR4, NLRP3, STAT3, TGF-ß, cyclin D1, and CDK2. CONCLUSION: Arctiin can enhance rats' behavior and structure of the hippocampus in AD rats. This is achieved through its ability to reduce the expression of both TLR4 and NLRP3, hence inhibiting the inflammasome pathway. Furthermore, Arctiin can improve tissue fibrosis by regulating STAT3 and TGF-ß. Lastly, it can block the cell cycle proteins cyclin D1 and CDK2.
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Introduction: Necrotizing enterocolitis (NEC) is a life-threatening inflammatory disease. Its onset might be triggered by Toll-Like Receptor 4 (TLR4) activation via bacterial lipopolysaccharide (LPS). We hypothesize that a deficiency of intestinal alkaline phosphatase (IAP), an enzyme secreted by enterocytes that dephosphorylates LPS, may contribute to NEC development. Methods: In this prospective pilot study, we analyzed intestinal resection specimens from surgical NEC patients, and from patients undergoing Roux-Y reconstruction for hepatobiliary disease as controls. We assessed IAP activity via enzymatic stainings and assays and explored IAP and TLR4 co-localization through immunofluorescence. Results: The study population consisted of five NEC patients (two Bell's stage IIb and three-stage IIIb, median (IQR) gestational age 25 (24-28) weeks, postmenstrual age at diagnosis 28 (26-31) weeks) and 11 controls (unknown age). There was significantly lower IAP staining in NEC resection specimens [49 (41-50) U/g of protein] compared to controls [115 (76-144), P = 0.03]. LPS-dephosphorylating activity was also lower in NEC patients [0.06 (0-0.1)] than in controls [0.3 (0.2-0.5), P = 0.003]. Furthermore, we observed colocalization of IAP and TLR4 in NEC resection specimens. Conclusion: This study suggests a significantly lower IAP level in resection specimens of NEC patients compared to controls. This lower IAP activity suggests a potential role of IAP as a protective agent in the gut, which needs further confirmation in larger cohorts.
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BACKGROUND: Trigeminal neuralgia (TN) is a common and difficult-to-treat neuropathic pain disorder in clinical practice. Previous studies have shown that Toll-like receptor 4 (TLR4) modulates the activation of the NF-κB pathway to affect neuropathic pain in rats. Voltage-gated sodium channels (VGSCs) are known to play an important role in neuropathic pain electrical activity. OBJECTIVE: To investigate whether TLR4 can regulate Nav1.3 through the TRAF6/NF-κB p65 pathway after infraorbital nerve chronic constriction injury (ION-CCI). STUDY DESIGN: ION-CCI modeling was performed on SD (Sprague Dawley) rats. To verify the success of the modeling, we need to detect the mechanical pain threshold and ATF3. Then, detecting the expression of TLR4, TRAF6, NF-κB p65, p-p65, and Nav1.3 in rat TG. Subsequently, investigate the role of TLR4/TRAF6/NF-κB pathway in ION-CCI model by intrathecal injections of LPS-rs (TLR4 antagonist), C25-140 (TRAF6 inhibitor), and PDTC (NF-κB p65 inhibitor). RESULTS: ION-CCI surgery decreased the mechanical pain threshold of rats and increased the expression of ATF3, TLR4, TRAF6, NF-κB p-p65 and Nav1.3, but there was no difference in NF-κB p65 expression. After inject antagonist or inhibitor of the TLR4/TRAF6/NF-κB pathway, the expression of Nav1.3 was decreased and mechanical pain threshold was increased. CONCLUSION: In the rat model of ION-CCI, TLR4 in the rat trigeminal ganglion regulates Nav1.3 through the TRAF6/NF-κB p65 pathway, and TLR4 antagonist alleviates neuropathic pain in ION-CCI rats.
Subject(s)
NAV1.3 Voltage-Gated Sodium Channel , Rats, Sprague-Dawley , Signal Transduction , TNF Receptor-Associated Factor 6 , Toll-Like Receptor 4 , Animals , Toll-Like Receptor 4/metabolism , TNF Receptor-Associated Factor 6/metabolism , Male , NAV1.3 Voltage-Gated Sodium Channel/metabolism , Signal Transduction/physiology , NF-kappa B/metabolism , Trigeminal Neuralgia/metabolism , Rats , Disease Models, Animal , Transcription Factor RelA/metabolism , Activating Transcription Factor 3/metabolism , Pain Threshold/physiologyABSTRACT
Antimicrobial resistance poses a serious threat to human health worldwide and its incidence continues to increase owing to the overuse of antibiotics and other factors. Macrolide antibiotics such as erythromycin (EM) have immunomodulatory effects in addition to their antibacterial activity. Long-term, low-dose administration of macrolides has shown clinical benefits in treating non-infectious inflammatory respiratory diseases. However, this practice may also increase the emergence of drug-resistant bacteria. In this study, we synthesized a series of EM derivatives, and screened them for two criteria: (i) lack of antibacterial activity and (ii) ability to suppress tumor necrosis factor-α (TNF-α) production in THP-1 cells stimulated with lipopolysaccharide. Among the 37 synthesized derivatives, we identified a novel 12-membered ring macrolide EM982 that lacked antibacterial activity against Staphylococcus aureus and suppressed the production of TNF-α and other cytokines. The effects of EM982 on Toll-like receptor 4 (TLR4) signaling were analyzed using a reporter assay and Western blotting. The reporter assay showed that EM982 suppressed the activation of transcription factors, NF-κB and/or activator protein 1 (AP-1), in HEK293 cells expressing human TLR4. Western blotting showed that EM982 inhibited the phosphorylation of both IκB kinase (IKK) ß and IκBα, which function upstream of NF-κB, whereas it did not affect the phosphorylation of p38 mitogen-activated protein kinase, extracellular signal-regulated kinase, and c-Jun N-terminal kinase, which act upstream of AP-1. These results suggest that EM982 suppresses cytokine production by inhibiting phosphorylation of IKKß and IκBα, resulting in the inactivation of NF-κB.
Subject(s)
Cytokines , I-kappa B Kinase , NF-KappaB Inhibitor alpha , Humans , I-kappa B Kinase/metabolism , Phosphorylation/drug effects , NF-KappaB Inhibitor alpha/metabolism , Cytokines/metabolism , Erythromycin/pharmacology , Erythromycin/chemistry , THP-1 Cells , Tumor Necrosis Factor-alpha/metabolism , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/chemistry , Macrolides/pharmacology , Macrolides/chemistry , NF-kappa B/metabolism , Signal Transduction/drug effects , Staphylococcus aureus/drug effects , Toll-Like Receptor 4/metabolismABSTRACT
OBJECTIVES: To observe the effects of moxibustion on intestinal barrier function and Toll-like receptor 4 (TLR4)/nuclear factor-κB p65 (NF-κB p65) signaling pathway in obese rats and explore the mechanism of moxibustion in the intervention of obesity. METHODS: Fifty-five Wistar rats of SPF grade were randomly divided into a normal group (10 rats) and a modeling group (45 rats). In the modeling group, the obesity model was established by feeding high-fat diet. Thirty successfully-modeled rats were randomized into a model group, a moxibustion group, and a placebo-control group, with 10 rats in each one. In the moxibustion group, moxibustion was applied at the site 3 cm to 5 cm far from the surface of "Zhongwan" (CV 12), with the temperature maintained at (46±1 ) â. In the placebo-control group, moxibustion was applied at the site 8 cm to 10 cm far from "Zhongwan" (CV 12), with the temperature maintained at (38±1) â. The intervention was delivered once daily for 8 weeks in the above two groups. The body mass and food intake of the rats were observed before and after intervention in each group. Using ELISA methool, the levels of serum triacylglycerol (TG), total cholesterol (TC) and lipopolysaccharide (LPS) were detected and the insulin resistance index (HOMA-IR) was calculated. HE staining was used to observe the morphology of colon tissue. The mRNA expression of zonula occludens-1 (ZO-1), Occludin, Claudin-1, TLR4 and NF-κB p65 in the colon tissue was detected by quantitative real-time PCR; and the protein expression of ZO-1, Occludin, Claudin-1, TLR4 and NF-κB p65 was detected by Western blot in the rats of each group. RESULTS: Compared with the normal group, the body mass, food intake, the level of HOMA-IR, and the serum levels of TC, TG and LPS were increased in the rats of the model group (P<0.01); those indexes in the moxibustion group were all reduced when compared with the model group and the placebo-control group respectively (P<0.01, P<0.05). Compared with the normal group, a large number of epithelial cells in the mucosa of colon tissue was damaged, shed, and the inflammatory cells were infiltrated obviously in the interstitium in the rats of the model group. When compared with the model group, in the moxibustion group, the damage of the colon tissue was recovered to various degrees and there were few infiltrated inflammatory cells in the interstitium, while, the epithelial injury of the colon tissue was slightly recovered and the infiltrated inflammatory cells in the interstitium were still seen in the placebo-control group. The mRNA and protein expressions of ZO-1, Occludin and Caudin-1 were decreased in the model group compared with those in the normal group (P<0.01). When compared with the model group and the placebo-control group, the mRNA and protein expressions of these indexes were increased in the moxibustion group (P<0.01, P<0.05). In the model group, the mRNA and protein expressions of TLR4 and NF-κB p65 were increased when compared with those in the normal group (P<0.01), and the mRNA and protein expressions of these indexes were reduced in the moxibustion group when compared with those in the model group and the placebo-control group (P<0.01). CONCLUSIONS: Moxibustion can reduce the body mass and food intake, regulate the blood lipid and improve insulin resistance in the rats of obesity. It may be related to alleviating inflammatory response through improving intestinal barrier function and modulating the intestinal TLR4/NF-κB p65 signaling pathway.
Subject(s)
Insulin Resistance , Moxibustion , Rats , Animals , NF-kappa B/genetics , NF-kappa B/metabolism , Rats, Wistar , Toll-Like Receptor 4/genetics , Lipopolysaccharides/metabolism , Intestinal Barrier Function , Occludin/metabolism , Claudin-1/metabolism , Signal Transduction , Obesity/genetics , Obesity/therapy , RNA, Messenger/metabolism , Tumor Necrosis Factor-alpha/metabolismABSTRACT
During an infection, innate immune cells must adjust nature and strength of their responses to changing pathogen abundances. To determine how stimulation of the pathogen sensing TLR4 shapes subsequent macrophage responses, we systematically varied priming and restimulation concentrations of its ligand KLA. We find that different priming strengths have very distinct effects at multiple stages of the signaling response, including receptor internalization, MAPK activation, cytokine and chemokine production, and nuclear translocation and chromatin association of NFκB and IκB members. In particular, restimulation-induced TNF-α production required KLA doses equal to or greater than those used for prior exposure, indicating that macrophages can detect and adaptively respond to changing TLR4 stimuli. Interestingly, while such adaptation was dependent on the anti-inflammatory cytokine IL-10, exogenous concentrations of IL-10 corresponding to those secreted after strong priming did not exert suppressive effects on TNF-α without such prior priming, confirming the critical role of TLR4 stimulation history.
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Background: Doxorubicin (Dox) can induce cardiotoxicity, thereby restricting the utility of this potent drug. Herein, the study ascertained the mechanism of the N6-methyladenosine (m6A) demethylase fat mass and obesity-associated protein (FTO) in pyroptosis and inflammation during Dox-induced heart failure (HF). Methods: Serum samples were collected from HF patients for detection of the expression of FTO and toll-like receptor 4 (TLR4). Dox-treated H9C2 cardiomyocytes were chosen for in vitro HF modeling, followed by measurement of FTO and TLR4 expression. Cardiomyocytes were detected for viability, apoptosis, spatial distribution of NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3), and the levels of lactic dehydrogenase, inflammatory factors, oxidative stress markers, and pyroptosis-related proteins. The m6A levels of mRNA were examined. RNA immunoprecipitation (RIP) and mRNA stability measurement were used to determine mRNA and protein expression, and RNA m6A dot blot and methylated-RIP assay were performed to detect m6A methylation levels. The expression of p-NF-κB p65 and p-IκB-α was measured by western blotting. Results: In the serum of HF patients, FTO was elevated while TLR4 was decreased. Dox treatment reduced FTO expression and increased m6A methylation levels and TLR4 expression in H9C2 cells. Overexpression of FTO and knockdown of TLR4 reduced apoptosis, cytotoxicity, inflammation, pyroptosis, oxidative stress, NLRP3 co-localization, and fluorescence intensity in Dox-induced H9C2 cells. Mechanistically, FTO resulted in reduced binding activity of YTHDF1 to TLR4 mRNA via m6A demethylation of TLR4, thus declining TLR4, p-NF-κB p65, and p-IκB-α expression. TLR4 knockdown counteracted the effects of FTO knockdown on Dox-induced H9C2 cells. Conclusions: FTO alleviated Dox-induced HF by blocking the TLR4/NF-κB pathway.
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BACKGROUND: Among adults, stroke is the main causes of mortality and permanent disability. Neuroinflammation is one of the main causes of stoke-mediated neuronal death. Our previous study revealed that (E)-5-(2-(Quinolin-4-yl) vinyl) benzene-1, 3-diol (RV01), a quinolinyl analog of resveratrol, inhibits microglia-induced neuroinflammation and safeguards neurons from inflammatory harm. The preventive role of RV01 in ischemic stroke and its underlying cellular mechanisms and molecular targets remain poorly understood. PURPOSE: To investigate whether RV01 alleviates ischemia-reperfusion (I/R) injury by inhibiting microglia-mediated neuroinflammation and determine the potential molecular mechanisms and targets by which RV01 inhibits the I/R-mediated microglia activation. METHODS: Rat middle cerebral artery occlusion and reperfusion (MCAO/R) and BV-2 or primary microglial cells oxygen-glucose deprivation and reperfusion (OGD/R) models were established. The neurological behavior scores, 2, 3, 5-triphenyl tetrazolium chloride staining and immunofluorescence were used to detect the neuroprotective effect of RV01 in the MCAO/R rats. In addition, the mRNA expression levels of IL-6, TNF-α, and IL-1ß were detected to reveal the antineuroinflammatory effect of RV01. Moreover, a western blot assay was performed to explore the protein expression changes in NF-κB-mediated neuroinflammation. Finally, we identified TLR4 as an RV01 target through molecular docking, drug sensitivity target stability analysis, cellular thermal shift analysis, and surface plasmon resonance techniques. RESULTS: RV01 reduced the infarct volume and neurological deficits, increased the rotarod duration, and decreased the number of rightward deflections in the MCAO/R rats. RV01 inhibited the NF-κB signaling pathway in vitro and in vivo, as demonstrated by the reduction in the transcription factor p65-mediated expression of several inflammatory factors including IL-6, TNF-α, and IL-1ß. Further studies showed that its protective effect was associated with targeting the TLR4 protein. Notably, the anti-inflammatory effect of RV01 was markedly reinforced by the TLR4 knockdown, but inhibited by the overexpression of TLR4. Results revealed that the conditioned medium derived from the RV01-treated BV-2 cells significantly decreased the OGD/R-mediated neuronal damage. CONCLUSION: Our results are the first to reveal the protective effects of RV01 on cerebral ischemia, depending on its inhibitory effect on the NF-κB pathway by targeting TLR4. RV01 could be a potential protective agent in ischemic stroke treatment.
Subject(s)
Anti-Inflammatory Agents , Infarction, Middle Cerebral Artery , Microglia , Neuroprotective Agents , Rats, Sprague-Dawley , Reperfusion Injury , Resveratrol , Toll-Like Receptor 4 , Animals , Toll-Like Receptor 4/metabolism , Male , Infarction, Middle Cerebral Artery/drug therapy , Reperfusion Injury/drug therapy , Microglia/drug effects , Resveratrol/pharmacology , Neuroprotective Agents/pharmacology , Rats , Anti-Inflammatory Agents/pharmacology , Ischemic Stroke/drug therapy , Disease Models, Animal , NF-kappa B/metabolism , Neuroinflammatory Diseases/drug therapy , Signal Transduction/drug effects , Molecular Docking SimulationABSTRACT
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.
Subject(s)
Acute Kidney Injury , Mitochondrial Diseases , Sepsis , Sulfonamides , Rats , Animals , NF-kappa B/metabolism , Toll-Like Receptor 4/metabolism , Signal Transduction , Acute Kidney Injury/drug therapy , Acute Kidney Injury/etiology , Acute Kidney Injury/prevention & control , Sepsis/complications , Sepsis/drug therapy , Sepsis/metabolismABSTRACT
Transient receptor potential vanilloid 1 (TRPV1), a ligand-gated cation channel, is a receptor for vanilloids on sensory neurons and is also activated by capsaicin, heat, protons, arachidonic acid metabolites, and inflammatory mediators on neuronal or non-neuronal cells. However, the role of the TRPV1 receptor in pro-inflammatory cytokine secretion and its potential regulatory mechanisms in lipopolysaccharide (LPS)-induced inflammation has yet to be entirely understood. To investigate the role and regulatory mechanism of the TRPV1 receptor in regulating LPS-induced inflammatory responses, bone marrow-derived macrophages (BMDMs) harvested from wild-type (WT) and TRPV1 deficient (Trpv1-/-) mice were used as the cell model. In WT BMDMs, LPS induced an increase in the levels of tumor necrosis factor-α, IL-1ß, inducible nitric oxide synthase, and nitric oxide, which were attenuated in Trpv1-/- BMDMs. Additionally, the phosphorylation of inhibitor of nuclear factor kappa-Bα and mitogen-activated protein kinases, as well as the translocation of nuclear factor kappa-B and activator protein 1, were all decreased in LPS-treated Trpv1-/- BMDMs. Immunoprecipitation assay revealed that LPS treatment increased the formation of TRPV1-Toll-like receptor 4 (TLR4)-cluster of differentiation 14 (CD14) complex in WT BMDMs. Genetic deletion of TRPV1 in BMDMs impaired the LPS-triggered immune-complex formation of TLR4, myeloid differentiation protein 88, and interleukin-1 receptor-associated kinase, all of which are essential regulators in LPS-induced activation of the TLR4 signaling pathway. Moreover, genetic deletion of TRPV1 prevented the LPS-induced lethality and pro-inflammatory production in mice. In conclusion, the TRPV1 receptor may positively regulate the LPS-mediated inflammatory responses in macrophages by increasing the interaction with the TLR4-CD14 complex and activating the downstream signaling cascade.
Subject(s)
Inflammation , Lipopolysaccharide Receptors , Lipopolysaccharides , Macrophages , Signal Transduction , TRPV Cation Channels , Toll-Like Receptor 4 , Animals , TRPV Cation Channels/metabolism , TRPV Cation Channels/genetics , TRPV Cation Channels/physiology , Toll-Like Receptor 4/metabolism , Toll-Like Receptor 4/genetics , Toll-Like Receptor 4/physiology , Macrophages/metabolism , Lipopolysaccharide Receptors/metabolism , Lipopolysaccharide Receptors/genetics , Inflammation/metabolism , Inflammation/genetics , Mice , Mice, Inbred C57BL , Mice, Knockout , MaleABSTRACT
Vizantin, 6,6'-bis-O-(3-nonyldodecanoyl)-α,α'-trehalose, has been developed as a safe immunostimulator on the basis of a structure-activity relationship study with trehalose 6,6'-dicorynomycolate. Our recent study indicated that vizantin acts as an effective Toll-like receptor-4 (TLR4) partial agonist to reduce the lethality of an immune shock caused by lipopolysaccharide (LPS). However, because vizantin has low solubility in water, the aqueous solution used in in vivo assay systems settles out in tens of minutes. Here, vizantin was chemically modified in an attempt to facilitate the preparation of an aqueous solution of the drug. This paper describes the concise synthesis of a water-soluble vizantin analogue in which all the hydroxyl groups of the sugar unit were replaced by sulfates. The vizantin derivative displayed micelle-forming ability in water and potent TLR-4 partial agonist activity.
Subject(s)
Glycolipids , Lipopolysaccharides , Trehalose/analogs & derivatives , Lipopolysaccharides/pharmacologyABSTRACT
BACKGROUND: Cinnamic acid, an active compound in cinnamon spp., has anti-inflammatory and antioxidant characteristics and is favorable in managing inflammatory bowel diseases. OBJECTIVES: Evaluate cinnamic acid's effects on colitis in rats. METHODS: To induce colitis in experimental rats, excluding the sham group, a 4% intrarectal solution of acetic acid was administered. The rats were then given oral doses of cinnamic acid at 30, 45, and 90 mg/kg for two days. The animals were assessed for macroscopic and microscopic changes, and the levels of inflammatory mediators such as tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and myeloperoxidase (MPO) were measured using Eliza kits. Additionally, real-time PCR was performed to examine the gene level of toll-like receptor 4 (TLR-4) in the colon. RESULTS: Effective reduction of inflammation in acetic acid-induced colitis was achieved through Cinnamic acid administration at doses of 45 and 90 mg/kg. The decrease was achieved by inhibiting the activities of TNF-α, IL-6, and MPO while downregulating the expression of TLR-4. It is important to note that macroscopic and microscopic evaluations were significant in determining the effectiveness of cinnamic acid in reducing inflammation. CONCLUSION: Downregulation of inflammatory cytokines and TLR-4 expression may contribute to cinnamic acid's anti-inflammatory effect.
Subject(s)
Acetic Acid , Anti-Inflammatory Agents , Cinnamates , Colitis , Disease Models, Animal , Peroxidase , Toll-Like Receptor 4 , Animals , Male , Rats , Anti-Inflammatory Agents/pharmacology , Anti-Inflammatory Agents/therapeutic use , Cinnamates/pharmacology , Cinnamates/therapeutic use , Colitis/drug therapy , Colitis/chemically induced , Colon/drug effects , Colon/pathology , Colon/metabolism , Interleukin-6/metabolism , Peroxidase/metabolism , Rats, Wistar , Toll-Like Receptor 4/metabolism , Tumor Necrosis Factor-alpha/metabolismABSTRACT
Histones organize DNA within cellular nuclei, but they can be released from damaged cells. In peripheral tissues extracellular histones act as damage-associated molecular patterns (DAMPs) inducing pro-inflammatory activation of immune cells. Limited studies have considered DAMP-like activity of histones in the central nervous system (CNS); therefore, we studied the effects of extracellular histones on microglia, the CNS immunocytes, and on neuronal cells. Both the linker histone H1 and the core histone H3 induced pro-inflammatory activation of microglia-like cells by upregulating their secretion of NO and cytokines, including interferon-γ-inducible protein 10 (IP-10) and tumor necrosis factor-α (TNF). The selective inhibitors MMG-11 and TAK-242 were used to demonstrate involvement of toll-like receptors (TLR) 2 and 4, respectively, in H1-induced NO secretion by BV-2 microglia. H1, but not H3, downregulated the phagocytic activity of BV-2 microglia. H1 was also directly toxic to all neuronal cell types studied. We conclude that H1, and to a lesser extent H3, when released extracellularly, have the potential to act as a CNS DAMPs. Inhibition of the DAMP-like effects of extracellular histones on microglia and their neurotoxic activity represents a potential strategy for combating neurodegenerative diseases that are characterized by the adverse activation of microglia and neuronal death.
Subject(s)
Histones , Microglia , Neurons , Histones/metabolism , Animals , Microglia/metabolism , Microglia/drug effects , Mice , Neurons/metabolism , Neurons/drug effects , Cytokines/metabolism , Neuroinflammatory Diseases/metabolism , Cell Line , Nitric Oxide/metabolismABSTRACT
INTRODUCTION: Toll-like receptor 4(TLR4) is a receptor that traditionally plays an important role in immunomodulation (regulation of the immune system) and the initiation of proinflammatory responses. TLR4 is used in the body to recognize molecular patterns of pathogens or damaged cells from outside. However, in recent years, it has also become clear that TLR4 can affect the immune system and the function of stem cells, especially mesenchymal stem cells. Therefore, understanding how TLR4 signaling works at the cellular and molecular level and using this knowledge in regenerative medicine could be potentially useful, especially in the treatment of adipose- derived mesenchymal stem cells (ADMSCs). How these cells can use TLR4 signaling when used to increase their regenerative potential and repair tissues is an area of research. AIMS: This study aims to elucidate the multifaceted role of TLR4-mediated signaling in ADMSCs. METHOD: Employing a comprehensive set of assays, including MTT for cell viability, flow cytometry for surface marker expression, and gene expression analysis, we demonstrate that TLR4 activation significantly modulates key aspects of ADMSC biology. Specifically, TLR4 signaling was found to regulate ADMSCs proliferation, surface marker expression, and regenerative capacity in a dose- and time-dependent manner. Furthermore, TLR4 activation conferred cytoprotective effects against Doxorubicin (DOX)-induced cellular apoptosis. RESULT: These findings suggest that TLR4 signaling could be used to enhance the regenerative abilities of ADMSCs and enable ADMSC-based therapies to be used more effectively for tissue engineering and therapeutic purposes. CONCLUSION: However, it is important to note that research in this area needs more details and clinical studies.
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ObjectiveTo investigate the protective effects of Mori Folium extract (MLE) on the kidney of db/db diabetic mice and its mechanism. MethodTwenty-four male C57BLKS/JGpt-Leprdb/Leprdb (db/db) mice were randomly divided into model group, metformin group, low-dose group of MLE (MLE-L), and high-dose group of MLE (MLE-H) according to their fasting blood glucose (FBG), with six mice in each group, and other six C57BLKS/JGpt wild littermate (m/m) mice were selected as normal group. The mice in the drug administration groups were given corresponding drugs by gavage, and the mice in the normal group and model group were given the same dose of deionized water by gavage once a day for continuous eight weeks. Body weight, bilateral kidney weight, and FBG were measured, and an oral glucose tolerance test (OGTT) was performed. The pathological changes in the kidney tissue of mice were observed by hematoxylin-eosin (HE) and periodic acid-silver (PAS) staining, and serum creatinine (SCr) and blood urea nitrogen (BUN) levels were detected. Enzyme-linked immunosorbent assay (ELISA) was used to detect the levels of tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) in serum and urinary microalbumin (U-mAlb) of mice. The expression levels of toll-like receptor 4 (TLR4), myeloid differentiation factor 88 (MyD88), and nuclear factor-kappa B p65 (NF-κB p65) protein in kidney tissue of mice were tested by Western blot. ResultCompared with the normal group, the body weight, absolute renal weight, FBG, and the area under the curve (AUC) of OGTT of mice in the model group were significantly increased (P<0.01), and the levels of SCr, BUN, and U-mAlb, as well as TNF-α and IL-6 in serum were significantly increased (P<0.01). The glomerular basement membrane in the kidney tissue of mice was thicker, with obvious inflammatory cell infiltration. The protein expression levels of TLR4, MyD88, and NF-κB p65 in the kidney tissue of mice were increased significantly (P<0.01). Compared with the model group, there was no statistical difference in the body weight of mice in each drug administration group. The absolute renal weight of mice in the MLE-H and metformin groups was significantly reduced (P<0.05, P<0.01). The FBG levels of mice in the metformin, MLE-L, and MLE-H groups started to decrease after treatment for four to eight weeks (P<0.05, P<0.01). The AUC of mice in the MLE-H and metformin groups was significantly decreased (P<0.01). The levels of SCr, BUN, and U-mAlb of mice in the MLE-H and metformin groups were significantly decreased (P<0.01), and those of SCr and U-mAlb of mice in the MLE-L group were significantly decreased (P<0.01). The levels of TNF-α and IL-6 in the serum of mice in the MLE-H and metformin groups were significantly decreased (P<0.01). The renal tissue pathology of mice in each drug administration group was improved to varying degrees, and the protein expression levels of TLR4, MyD88, and NF-κB p65 in the MLE-H group were decreased significantly (P<0.05, P<0.01). ConclusionMLE can improve the renal structure and function of db/db diabetic mice, and its mechanism may be related to the inhibition of the TLR4/MyD88/NF-κB signaling pathway.
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Objective To investigate the ameliorative effect of sulforaphane on inflammatory response and airway remodeling in rats with chronic obstructive pulmonary disease(COPD).Methods Seventy-five SD rats were randomly divided into the normal group,the model group,and the low-,medium-,and high-dose groups of sulforaphane,with 15 rats in each group.Except for the normal group,the COPD model was prepared in the remaining group using aroma smoke inhalation combined with intratracheal droplet lipopolysaccharide(LPS)method.After the successful modelling,the rats were administered the drug by gavage for 28 days.At the end of the administration,the general conditions of the rats in each group were observed,and the lung function[forced vital capacity(FVC),peak expiratory flow-rate(PEF),forceful expiratory volume in 1 second(FEV1)]was examined,and the pathological changes of the lung tissues were observed by hematoxylin-eosin(HE)staining method,and the indexes of airway remodeling(thickness of the bronchial wall,thickness of the smooth muscle)were measured;the enzyme-linked immunosorbent assay(ELISA)was used to examine the lung function of the rats.The levels of inflammatory factors[tumor necrosis factor α(TNF-α),interleukin 1β(IL-1β)]were detected in lung tissue by enzyme-linked immunosorbent assay(ELISA),and changes in the protein expressions of Toll-like receptor 4(TLR4),myeloid differentiation factor 88(MyD88),and nuclear transcription factor κB(NF-κB)were detected in lung tissue by Western Blot.Results(1)The rats in the model group had dry and lack of glossy fur,obvious coughing and nose scratching,shortness of breath,slow movement,and preferred to arch their backs and lie curled up;the rats in the low-,medium-and high-dose groups of sulforaphane showed significant improvement in shortness of breath,coughing,and other abnormal manifestations.(2)HE staining showed that the airway wall and smooth muscle of rats in the model group were thickened,the airway epithelium was damaged,and alveolar destruction,fusion,and massive infiltration of inflammatory cells were seen;the histopathological changes in the lungs of rats in the low-,medium-and high-dose groups of sulforaphane improved to varying degrees,with the airway wall becoming thinner,the degree of alveolar destruction being reduced,and the infiltration of inflammatory cells being reduced.(3)Compared with the normal group,FVC,PEF and FEV1 were significantly reduced in the model group(P<0.05),and the levels of TNF-α and IL-1β,bronchial wall thickness,smooth muscle thickness,and the expression levels of TLR4,MyD88 and NF-κB were significantly increased in the model group(P<0.05);and in comparison with the model group,the levels of FVC,PEF,and FEV1 were significantly increased in the rats in the sulforaphane low-,medium-,and high-dose groups(P<0.05),and the levels of TNF-α,IL-1β,bronchial wall thickness,smooth muscle thickness,and the expression levels of TLR4,MyD88,and NF-κB were significantly decreased(P<0.05)compared with the model group.Conclusion Sulforaphane helps to inhibit the inflammatory response,attenuate airway remodeling,and improve the pathological injury and lung function of lung tissue in rats with COPD,and its mechanism may be related to the inhibition of TLR4,MyD88,and NF-κB protein expressions.
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Objective:To determine the effect of gastrodin(GAS)on toll-like receptor 4(TLR4)expression in mi-croglia after hypoxic-ischemic brain damage.Methods:Hypoxia-ischemic brain damage(HIBD)model was established in neonatal rat in vivo.Thirty 3 d SD rats of were randomly divided into there groups:Sham group,HIBD model group,HIBD model+gastrodin intervention group(HIBD+G).Oxygen glucose deprivation(OGD)model was established in BV2 cells in vitro,Control group(Control),oxygen glucose deprivation group(OGD),OGD+gastrodin intervention group(OGD+G)were randomly set in vitro.Both Western Blot and immunofluorescence staining techniques were used to detect the expression of TLR4 in cells of each group in vitro and in the left corpus callosum region in vivo.Results:The expression of TLR4 was significantly increased in OGD-induced microglia.After gastrodin intervention,TLR4 expression was decreased significantly(P<0.05).Conclusion:GAS can inhibit the expression of TLR4 in activated microglia and thus play a neuroprotective role in HIBD.
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ObjectiveTo observe the effect of Scutellariae Radix-Coptidis Rhizoma on plaque stability in atherosclerotic (AS) mice and to explore its possible mechanism of action based on the Toll-like receptor 4 (TLR4)/myeloid differentiation factor 88 (MyD88)/nuclear factor kappa B (NF-κB) signaling pathway. MethodTen normal C57BL/6J mice were used as the normal group, and the same strain of ApoE knockout (ApoE-/-) mice were fed with a high-fat diet for 12 weeks to construct an atherosclerosis model. Mice were randomly divided into five groups, namely the model group, the atorvastatin group, and the Scutellariae Radix-Coptidis Rhizoma low-, medium-, and high-dose groups, with ten mice in each group. Then normal and model groups were given equal volume of saline gavage, and the low-, medium-, high-dose Scutellariae Radix-Coptidis Rhizoma groups were given 1.95, 3.9, 7.8 g·kg-1 of the drug by gavage for 8 weeks, respectively. The general state of mice was observed. Hematoxylin-eosin staining was utilized to observe the pathology of aortic root plaques and calculate the percentage of plaque area. Masson staining and oil red O staining combined with immunohistochemistry of F4/80 and α-SMA were used to detect the plaque components of aortic root plaques and calculate the plaque vulnerability index. Enzyme-linked immunosorbent assay was adopted to detect the expression levels of serum tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). Western blot was applied to detect the protein expression levels of matrix metalloproteinase-2 (MMP-2), matrix metalloproteinase-9 (MMP-9), TLR4, MyD88, NF-κB p65, and phosphorylation (p) -NF-κB p65 in the aortic tissues of mice in each group. Real-time fluorescence quantitative polymerase chain reaction (Real-time PCR) assay was employed to detect the expression levels of MMP-2, MMP-9, TLR4, and MyD88, NF-κB p65 mRNA. ResultCompared with the model group, the general state of the mice in each medication group was improved, and no obvious side effects were observed. Compared with the model group, the percentage of plaque area in the aortic root of AS mice was significantly reduced in the medium- and high-dose Scutellariae Radix-Coptidis Rhizoma groups (P<0.05). The content of collagen fibers and smooth muscle cells in the plaques of the high-dose Scutellariae Radix-Coptidis Rhizoma group was significantly increased (P<0.01), and the content of lipids and macrophages was significantly reduced (P<0.05), the plaque vulnerability index of each dose group of Scutellariae Radix-Coptidis Rhizoma was significantly reduced, with significant reduction of the medium- and high-dose groups (P<0.01). MMP-2 and MMP-9 protein and mRNA expression levels in aortic tissues were significantly reduced in medium- and high-dose Scutellariae Radix-Coptidis Rhizoma groups (P<0.05). The serum levels of TNF-α and IL-6 were significantly reduced in AS mice in medium- and high-dose Scutellariae Radix-Coptidis Rhizoma groups (P<0.05). In the medium- and high-dose Scutellariae Radix-Coptidis Rhizoma groups, the levels of TLR4, MyD88 protein, and mRNA expression in aortic tissues were significantly reduced (P<0.05), and the level of NF-κB p65 phosphorylation in aortic tissues was significantly reduced (P<0.05). ConclusionScutellariae Radix-Coptidis Rhizoma may play an anti-inflammatory and stabilizing role by inhibiting the TLR4/MyD88/NF-κB signaling pathway.
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ObjectiveTo observe the effect of Zuoguiwan on ovarian reserve in the female offspring rat model of prenatal stress (PS) and explore the mechanism based on Toll-like receptor 4/nuclear factor-κB p65 (TLR4/NF-κB p65) signaling pathway. MethodThirty-two pregnant rats were prepared and randomized into four groups (n=8): control, model, Zuoguiwan (18.9 mg·kg-1), and vitamin E (1.44 mg·kg-1). Except the control group, the other three groups were subjected to chronic unpredictable mild stress (CUMS) from day 11 of pregnancy, and the modeling was accompanied by gavage with corresponding drugs until delivery. The PS model was evaluated by the sucrose preference test, open field test, and serum corticosterone (CORT) level. The estrous cycle was monitored and the morphological changes in the ovarian tissue were observed. The serum levels of estradiol (E2), luteinizing hormone (LH), follicle-stimulating hormone (FSH), and anti-Mullerian hormone (AMH) in the 75-day-old offspring rats were measured by enzyme-linked immunosorbent assay (ELISA) to evaluate the ovarian reserve. The ovary and uterus indices were calculated. The serum levels of interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) were measured by enzyme-linked immunosorbent assay (ELISA). The morphology of the ovarian tissue in the offspring on the day of birth and day 75 after birth was observed by hematoxylin-eosin staining. The transport of NF-κB p65 to the nucleus in the ovaries of the 75-day-old offspring was detected by the immunofluorescence (IF) assay. The expression of TLR4, NF-κB p65 and other related proteins in the ovarian tissue was determined by Western blot. ResultCompared with the control group, the model group showed reduced primordial follicles in the offspring on the day of birth (P<0.01) as well as disturbed estrous cycle, decreased ovary index and uterus index (P<0.01), reduced corpus luteum, increased atretic follicles (P<0.01), lowered serum levels of AMH and E2 (P<0.01), elevated serum levels of LH, FSH, IL-1β, and TNF-α (P<0.05, P<0.01), and up-regulated protein levels of TLR4, NF-κB p65, recombinant myeloid differentiation factor 88 (MyD88), and phosphorylated NF-κB inhibitor (p-IκBα) (P<0.01) in the 75-day-old offspring rats. Compared with the model group, Zuoguiwan and vitamin E increased the primordial follicles in the offspring on the day of birth (P<0.01). Moreover, they resumed the estrous cycle, increased the ovary and uterine indices (P<0.05, P<0.01) and corpus luteum (P<0.01), reduced atretic follicles (P<0.01), elevated the serum levels of AMH and E2 (P<0.05, P<0.01), lowered the serum levels of LH, FSH, IL-1β, and TNF-α (P<0.05, P<0.01), and down-regulated the expression of TLR4, NF-κB p65, MyD88, and p-IκB-α (P<0.05, P<0.01) in the 75-day-old offspring. ConclusionZuoguiwan can improve the ovarian reserve in the offspring rat model of congenital kidney deficiency by regulating the TLR4/NF-κB p65 signaling pathway.
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ObjectiveTo explore the protective effect and mechanism of Zingiberis Rhizoma Recens alcohol extract on lipopolysaccharide (LPS)-induced acute lung injury in mice. MethodBalb/c mice were randomly divided into normal group, model group, dexamethasone group, and low- and high-dose Zingiberis Rhizoma Recens groups. Mice in the normal group were instilled with normal saline through the nose, and the other groups were instilled with normal saline containing LPS (50 μg). After 30 minutes of modeling, the dexamethasone group was gavaged with 5 mg·kg-1 of dexamethasone acetate solution, the low- and high-dose Zingiberis Rhizoma Recens groups were gavaged with different doses of (7, 14 g·kg-1) of Zingiberis Rhizoma Recens alcohol extract, and the normal group and the model group were gavaged with the same volume of water. After 24 hours of modeling, the total number of white blood cells in bronchoalceolar lavage fluid (BALF) was detected by cell counter, and the levels of the inflammatory factors including tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, and superoxide dismutase (SOD), and myeloperoxidase (MPO) was detected by enzyme-linked immunosorbent assay (ELISA). Haematoxylin-eosin (HE) staining method was used to observe the pathological changes of lung tissue in each group, and the Western blot was used to detect the protein expression of nuclear transcription factor (NF)-κB p65, phosphorylation (p)-NF-κB p65, and Toll-like receptor 4 (TLR4) in lung tissue. ResultCompared with the normal group, the white blood cell count in BALF and the levels of TNF-α, IL-1β, IL-6, and MPO in the model group was increased (P<0.01), and the level of SOD was decreased (P<0.05). Pathological damage of lung tissue was obvious, and the protein expression of NF-κB p65, p-NF-κB p65, and TLR4 in lung tissue was increased (P<0.01). Compared with the model group, the white blood cell count in BALF and the levels of TNF-α, IL-1β, IL-6, and MPO in the treatment group was decreased (P<0.05,P<0.01), and the level of SOD was increased (P<0.05,P<0.01). Pathological damage of lung tissue was alleviated, and the protein expression of NF-κB p65, p-NF-κB p65, and TLR4 in lung tissue was decreased (P<0.01). ConclusionZingiberis Rhizoma Recens alcohol extract may play a protective role in LPS-induced acute lung injury in mice by inhibiting the TLR4/NF-κB signaling pathway.