Toll-like Receptor 4 Protein Research Articles

Electroacupuncture improves behavioral activities by suppressing neuroinflammation and TLR4/NF-κB signaling in substantia nigra of midbrain in Parkinson's disease rats

To observe the effect of electroacupuncture(EA) at "Fengfu" (GV16) and "Taichong"(LR3) on the expression of tyrosine hydroxylase (TH), α-synuclein (α-syn) and microglial-related microglial (MG), Toll-like receptor 4（TLR4）/nuclear factor kappa B （NF-κB） signaling pathway in the substantia nigra (SN) of midbrain in Rotenone-induced Parkinson's disease (PD) rats, so as to explore its mechanisms underlying improvement of PD. SD male rats were randomly divided into normal control, PD model and EA groups (n=12 in each group). The PD model was established by subcutaneous injection of rotenone (1 mg/kg) at the back of neck. EA (2 Hz, 1 mA) was applied to bilateral GV16 and LR3, once daily for 2 weeks. The rats' behavior(hair color, reaction capacity, locomotion and gait state)scores (0-10 points) were given and the autonomic movement state (trajectory of autonomous motion, total distance, average speed and duration of motion in 8 min) was detected by using open field tests. The immunoactivity of TH and α-syn in the SN tissue were determined by using immunohistochemistry staining, and the number of Iba-1-labelled microglia (MG) was detected by using immunofluorescence staining. The expression levels of TLR4 and NF-κB P65 proteins in the SN were detected by Western blot, and the contents of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in the SN were determined by using enzyme-linked immunosorbent assay. In comparison with the normal group, the behavioral score, α-syn immunoactivity, number of Iba-1 labelled microglia, expression of TLR4 and NF-κB P65 proteins and the contents of TNF-α and IL-6 in the SN were significantly increased (P<0.01), whereas the total distance, average speed, duration of motion of the autonomic movement in 8 min, and the TH immunoactivity were remarkably decreased in the model group (P<0.01). After EA intervention, compared with the model group, the increase of the behavioral score, α-syn immunoactivity, number of Iba-1-labelled microglia, expression of TLR4 and NF-κB P65 proteins, the contents of TNF-α and IL-6 in the SN, and the decrease of the total distance, average speed, duration of motion of the autonomic movement in 8 min, and the TH immunoactivity were reversed (P<0.05, P<0.01). EA can improve the behavioral manifestations of PD rats, which may be associated with its functions in down-regulating the abnormal accumulation of pathological α-syn, TLR4/NF-κB signaling, inhibiting activities of microglia and in up-regulating the expression of TH in the SN of midbrain.

Contribution of the mutation rs8193069 in TLR4 to mastitis resistance and performance in Holstein cows in southern China.

Bovine mastitis has become increasingly important issues for farmers and consumers, leading to large economic losses in the dairy industry worldwide. Because treatment of mastitis is difficult and costly, improved mastitis resistance through selective breeding would be advantageous. The toll‐like receptor 4 (TLR4) is an important player in recognising pathogens and activating immune responses. However, its roles in mastitis occurrence and the underlying molecular mechanisms are unclear. In this study, a single nucleotide polymorphism, rs8193069 (T → C) in TLR4 gene was detected in a Holstein cow resource population in southern China. Association analysis with 5‐year production traits, haematology, and biochemistry parameters revealed that individuals with genotype CC had significantly lower somatic cell counts (SCC), lower fat percentage, but higher 305‐day milk (p < 0.05) and total milk yield (p < 0.01). Both genotypes CC and CT had lower lymphocyte counts (#LYMPH) (p < 0.01) and basophil counts (#BASO) (p < 0.05) than TT. Genotype CC had a less level of triglyceride (p < 0.01) and creatine kinase (p < 0.05) than CT. Further analysis based on the production data revealed significant positive correlations between SCC and #LYMPH. Analysis of TLR4 protein structure and properties suggested that the missense mutation on the 674th amino acid from Thr to Ile reduced the flexibility and hydrophilicity of TIR domain, implying a weakened binding ability of TLR4 to its adaptors. In conclusion, allele C of rs8193069 was the major allele in Holstein cows that indicated a greater genetic potential to mastitis resistance and milk yields, probably via the LPS‐TLR4 inflammatory signalling. This study offers a marker to improve mastitis resistance in the dairy cow population in southern China.

The Role of TLR4 Inducing Macrophage Pyroptosis in the Pathogenesis of Severe Aplastic Anemia

Introduction：To investigate the expression level of macrophage pyroptosis in patients with severe aplastic anemia (SAA) and its effect on downstream effector T cells, the study explored the mechanism of Toll like receptor 4 (TLR4) inducing macrophage pyroptosis and maintaining immune homeostasis of SAA through pyruvate kinase M2 (PKM2) at cellular and molecular levels, which provided a theoretical basis for the targeted therapy of macrophages in SAA. Three groups of bone marrow macrophages of new diagnosed SAA patients, remission patients and healthy controls were induced and cultured in vitro. qRT-PCR and Western Blot were used to detect pyroptosis-related indicators IL-1β, IL-18, NLRP3, Caspase-1 and GSDMD expression level; ELISA to detect the concentration of IL-1β and IL-18 in the culture supernatant.Results: 1. The mRNA and protein levels of macrophages IL-1β, IL-18, NLRP3, Caspase-1, and GSDMD in the new diagnosed SAA group were significantly higher than those in healthy controls, and the IL-1β and IL-18 concentration in the macrophage culture supernatant increased significantly. The relative mRNA expression levels of macrophages IL-1β, IL-18, NLRP3, Caspase-1, and GSDMD in the new diagnosed group were significantly negatively correlated with WBC, RBC, Hb and PLT. 2. The relative expression level of TLR4 mRNA in macrophages in the new diagnosed group was significantly higher than that in the remission group and healthy controls, and the protein level of TLR4 was significantly increased; at the same time, the relative expression level of TLR4 mRNA was positively correlated with IL-1β, IL-18, NLRP3, Caspase-1 and GSDMD in macrophages. After knocking down TLR4 or adding TLR4 inhibitors, the mRNA and protein expression levels of IL-1β, IL-18, NLRP3, Caspase-1 and GSDMD were significantly lower than those in healthy controls, and the concentration of IL-1β and IL-18 in the culture supernatant reduced significantly. 3. The expression rate of PKM2 in macrophages of new diagnosed group by flow cytometry was significantly higher than that in the remission group and heathy controls, and the levels of PKM2 mRNA and protein were significantly increased. At the same time, the relative expression level of PKM2 mRNA was positively correlated with the expression levels of IL-1β, IL-18, NLRP3, Caspase-1, and GSDMD. After knocking down PKM2, the mRNA and protein expression levels of IL-1β, IL-18, NLRP3, Caspase-1, GSDMD were significantly lower than those healthy controls, and the concentration of IL-1β and IL-18 in the culture supernatant was also significantly reduced. After knocking down TLR4 or adding TLR4 inhibitor, PKM2 mRNA and protein expression levels in macrophages were significantly lower than those in healthy controls. 4. When CD8+ T cells were co-cultured with macrophages which were knocked down TLR4 or added with inhibitors, the expressions of perforin and granzyme B in CD8+ T cells were significantly reduced. CD8+ T cells were further co-cultured with K562 and the apoptosis level of K562 was reduced.Summary：The level of macrophage pyroptosis in SAA patients increased, and the expression levels of macrophages TLR4 and PKM2 increased and positively correlated with the level of pyroptosis. Inhibiting the expression of TLR4 and PKM2, respectively, reduced the level of macrophage pyroptosis, and at the same time inhibiting TLR4 expression reduced the expression of PKM2. Macrophages that inhibited TLR4 expression reduced the killing function of CD8+ T cells. Therefore, TLR4 may induce pyroptosis of macrophages in SAA patients through PKM2 and enhance the killing function of CD8+ T cells. DisclosuresNo relevant conflicts of interest to declare.

Synonymous and non-synonymous polymorphisms in toll-like receptor 2 (TLR2) gene among complicated measles cases at a tertiary care hospital, Peshawar, Pakistan.

Objectives:To detect single nucleotide polymorphism in toll-like receptor 2 (TLR2) gene in complicated cases of measles, in order to understand the genetic basis of complex human immune responses against measles complications.Methods:A total of 100 children consisted of 50 measles complicated cases while rest were gender matched disease-free individuals who served as controls for this study. Patient demographic data and clinical information were recorded on a separate pre-designed model form. All exonic regions of TLR2 gene of the patients and control samples were amplified through polymerase chain reaction. Various in-silico mutation verification tools like protein variation effect analyzer, MUPRO, sorting intolerant from tolerant, functional analysis through hidden Markov models, and polymorphism phenotyping v2 to study the effect of novel non-synonymous polymorphism on structure and function of TLR2 protein.Results:Synonymous and novel non-synonymous polymorphisms were identified in measles complicated cases. Among these, rs1816702 was marked to 5 untranslated region section of TLR2 gene, while rs3804099 and rs3804100 were identified in the coding region. Novel non-synonymous polymorphisms were shown in the coding region of TLR2 gene. No significant association was established between the observed genetic polymorphisms and measles complications. However, rs3804100 increased the risk of lower respiratory tract infection.Conclusion:The overall impact of novel non-synonymous polymorphism of TLR2 protein structure and functions was neutral and tolerated.

Effect of electroacupuncture stimulation of different acupoint groups on lipid metabolism and liver TLR4/NF-κB signaling in obese rats

To observe the effect of electroacupuncture (EA) of different acupoint combinations on lipid metabolism and liver Toll-like receptor 4 (TLR4)/nuclear factor kappa B (NF-κB) signaling in obese rats, so as to explore the specificity of regulatory effects of different acupoints for obesity. Male SD rats were randomly divided into normal control, model, hindlimb acupoint EA ［"Fenglong" (ST40)-"Zusanli" (ST36), hindlimb EA］, abdominal acupoint EA ［("Zhongwan" (CV12)-"Tianshu" (ST25), "Guanyuan" (CV4) - the opposite ST25, abdominal EA］, BiaoBen-acupoint EA ［ST40-ST36, CV12 -CV4, ST25, BiaoBen EA］ groups, with 10 rats in each group. The obesity model was induced by feeding the rats with high fat diet. EA (2 Hz, 1 mA) was applied to the acupoint groups mentioned above for 10 min (per acupoint group), 3 times a week for 8 weeks. After the treatment, the body weight and food intake in each group were recorded. The contents of serum total cholesterol (TC), triglyceride (TG), non-esterified fatty acid (NEFA) were detected by using an automatic biochemical analyzer. The expression levels of TLR4 and NF-κB p65 mRNAs and proteins in the liver tissue were detected by quantitative real-time PCR and Western blot, separately. Compared with the normal group, the body weight and food intake, serum TC, TG and NEFA contents, hepatic TLR4 and NF-κB p65 protein and gene expression were significantly increased in the model group (P<0.05, P<0.01). After the treatment, compared with the model group, the body weight, food intake, TC, TG, NEFA, TLR4 and NF-κB p65 protein and mRNA expression were significantly decreased in the hindlimb EA, abdominal EA and BiaoBen EA groups (P<0.05, P<0.01). Comparison among the 3 treatment groups showed that the serum TC, TG and NEFA contents were significantly lower in the hindlimb EA and BiaoBen EA groups than in the abdominal EA group (P<0.01，P<0.05). The expression levels of TLR4 and NF-κB p65 mRNAs and proteins were significantly lower in the BiaoBen EA group than in the hindlimb EA and abdominal EA groups (P<0.01, P<0.05). BiaoBen EA is superior to abdominal EA in improving lipid metabolism in obesity rats, which may be related to its stronger effectiveness in down-regulating hepatic TLR4/NF-κB p65 signaling.

Effect of Erdosteine on Middle Ear Effusion in Rats by Mediating TLR4 Signaling Pathway.

The study aimed to investigate the effect of erdosteine on middle ear effusion in rats through mediating the Toll-like receptor 4 (TLR4) signaling pathway. Rats were injected with endotoxin to prepare the model of acute secretory otitis media (SOM). Then, they were divided into an acute SOM model group (model group, n = 15) and erdosteine treatment group (18 mg/kg, gavage, treatment group, n = 15). Besides, a normal group (n = 15) was set up. Two weeks later, routine biochemical indicators such as aspartate aminotransferase (AST) and alkaline phosphatase (ALP) were detected. The inflammatory effusion due to otitis media was scored. The content of myeloperoxidase (MPO), matrix metalloproteinase (MMP), and tumor necrosis factor-beta (TNF-β) in middle ear lavage fluid was detected via enzyme-linked immunosorbent assay (ELISA). Additionally, histomorphological changes were observed with the help of hematoxylin-eosin (HE) staining, and quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and Western blotting assays were carried out to measure the expression levels of TLR4 pathway genes and proteins as well as the messenger ribonucleic acid (mRNA) expression levels of key factors for otitis media (mucin 2 (MUC2) and MUC5A). In the model group, the levels of AST, ALP, and glutamic-pyruvic transaminase (GPT) were significantly increased (p < 0.05). Besides, the content of MPO, MMP, and TNF-β was overtly raised in the model group (p < 0.05), while it was notably lowered in the treatment group (p < 0.05). In the treatment group, the cilia were slightly swollen, and inflammatory cells were fewer. The mRNA levels of MUC2, MUC5A, and pathway genes TLR4 and c-Jun N-terminal kinase (JNK) were elevated in the model group. In addition, the protein assay results revealed that the protein levels of TLR4 and JNK were evidently increased in the model group. Erdosteine can treat the middle ear effusion in rats by repressing the activation of the TLR4 signaling pathway.

Hydroxychloroquine inhibits proteolytic processing of endogenous TLR7 protein in human primary plasmacytoid dendritic cells.

Toll-like receptor 7 (TLR7) triggers antiviral immune responses through its capacity to recognize ssRNA. Proteolytic cleavage of TLR7 protein is required for its functional maturation in the endosomal compartment. Structural studies demonstrated that the N- and C-terminal domains of TLR7 are connected and involved in ligand binding after cleavage. Hydroxychloroquine (HCQ), an antimalarial drug, has been studied for its antiviral effects. HCQ increases pH in acidic organelles and has been reported to potently inhibit endosomal TLR activation. Whether HCQ can prevent endogenous TLR7 cleavage in primary immune cells, such as plasmacytoid DCs (pDCs), had never been examined. Here, using a validated anti-TLR7 antibody suitable for biochemical detection of native TLR7 protein, we show that HCQ treatment of fresh PBMCs, CAL-1 leukemic, and primary human pDCs inhibits TLR7 cleavage and results in accumulation of full-length protein. As a consequence, we observe an inhibition of pDC activation in response to TLR7 stimulation with synthetic ligands and viruses including inactivated SARS-CoV2, which we show herein activates pDCs through TLR7-signaling. Together, our finding suggests that the major pathway by which HCQ inhibits ssRNA sensing by pDCs may rely on its capacity to inhibit endosomal acidification and the functional maturation of TLR7 protein.

Toll like receptors and their evolution in the lymnaeid freshwater snail species Radix auricularia and Lymnaea stagnalis, key intermediate hosts for zoonotic trematodes

One of the major evolutionarily conserved pathways in innate immunity of invertebrates is the toll-like receptor (TLR) pathway. However, little is known of the TLR protein family in gastropod molluscs despite their role in the transmission of human diseases, especially the common lymnaeid freshwater snail species Radix auricularia and Lymnaea stagnalis, key intermediate hosts of zoonotic trematodes. Using comparative genomics and gene prediction approaches utilising the freshwater snail Biomphalaria glabrata genome as a reference ten putative TLR proteins were identified in both R. auricularia and L. stagnalis. Phylogenetic analyses revealed that unlike other molluscs the lymnaeid species also possessed class 1 TLRs, previously thought to be unique to B. glabrata. Gene duplication events were also seen across the TLR classes in the lymnaeids with several of the genes appearing to exist as potential tandem elements in R. auricularia. Each predicted TLR was shown to possess the typical the leucine-rich repeat extracellular and TIR intracellular domains and both single cysteine clusters and multiple cysteine clusters TLRs were identified in both lymnaeid species. Principle component analyses of 3D models of the predicted TLRs showed that class 1 and 5 proteins did not cluster based on similarity of structure, suggested to be potential adaptation to a range of pathogens. This study provides the first detailed account of TLRs in lymnaeids and affords a platform for further research into the role of these proteins into susceptibility and compatibility of these snails with trematodes and their role in transmission.

CTRP3 protects against uric acid-induced endothelial injury by inhibiting inflammation and oxidase stress in rats.

Hyperuricemia, which contributes to vascular endothelial damage, plays a key role in multiple cardiovascular diseases. This study was designed to investigate whether C1q/tumor necrosis factor (TNF)-related protein 3 (CTRP3) has a protective effect on endothelial damage induced by uric acid and its underlying mechanisms. Animal models of hyperuricemia were established in Sprague-Dawley (SD) rats through the consumption of 10% fructose water for 12 weeks. Then, the rats were given a single injection of Ad-CTRP3 or Ad-GFP. The animal experiments were ended two weeks later. In vitro, human umbilical vein endothelial cells (HUVECs) were first infected with Ad-CTRP3 or Ad-GFP. Then, the cells were stimulated with 10 mg/dL uric acid for 48 h after pretreatment with or without a Toll-like receptor 4 (TLR4)-specific inhibitor. Hyperuricemic rats showed disorganized intimal structures, increased endothelial apoptosis rates, increased inflammatory responses and oxidative stress, which were accompanied by reduced CTRP3 and elevated TLR4 protein levels in the thoracic aorta. In contrast, CTRP3 overexpression decreased TLR4 protein levels and ameliorated inflammatory responses and oxidative stress, thereby improving the morphology and apoptosis of the aortic endothelium in rats with hyperuricemia. Similarly, CTRP3 overexpression decreased TLR4-mediated inflammation, reduced oxidative stress, and rescued endothelial damage induced by uric acid in HUVECs. In conclusion, CTRP3 ameliorates uric acid-induced inflammation and oxidative stress, which in turn protects against endothelial injury, possibly by inhibiting TLR4-mediated inflammation and downregulating oxidative stress.

TLR4 and AT1R mediate blood-brain barrier disruption, neuroinflammation, and autonomic dysfunction in spontaneously hypertensive rats

Angiotensin II (AngII) is implicated in neuroinflammation, blood-brain barrier (BBB) disruption, and autonomic dysfunction in hypertension. We have previously shown that exogenous AngII stimulates Toll-like receptor 4 (TLR4) via AngII type 1 receptor (AT1R), inducing activation of hypothalamic microglia ex vivo, and that AngII-AT1R signaling is necessary for the loss of BBB integrity in spontaneously hypertensive rats (SHRs). Herein, we hypothesized that microglial TLR4 and AT1R signaling interactions represent a crucial mechanistic link between AngII-mediated neuroinflammation and BBB disruption, thereby contributing to sympathoexcitation in SHRs. Male SHRs were treated with TAK-242 (TLR4 inhibitor; 2 weeks), Losartan (AT1R inhibitor; 4 weeks), or vehicle, and age-matched to control Wistar Kyoto rats (WKYs). TLR4 and AT1R inhibitions normalized increased TLR4, interleukin-6, and tumor necrosis factor-α protein densities in SHR cardioregulatory nuclei (hypothalamic paraventricular nucleus [PVN], rostral ventrolateral medulla [RVLM], and nucleus tractus solitarius [NTS]), and abolished enhanced microglial activation. PVN, RVLM, and NTS BBB permeability analyses revealed complete restoration after TAK-242 treatment, whereas SHRs presented with elevated dye leakage. Mean arterial pressure was normalized in Losartan-treated SHRs, and attenuated with TLR4 inhibition. In conscious assessments, TLR4 blockade rescued SHR baroreflex sensitivity to vasoactive drugs, and reduced the SHR pressor response to ganglionic blockade to normal levels. These data suggest that TLR4 activation plays a substantial role in mediating a feed-forward pro-hypertensive cycle involving BBB disruption, neuroinflammation, and autonomic dysfunction, and that TLR4-specific therapeutic interventions may represent viable alternatives in the treatment of hypertension.

Low-grade elevation of palmitate and lipopolysaccharide synergistically induced β-cell damage via inhibition of neutral ceramidase

High concentrations of free fatty acids (FFAs) or lipopolysaccharide (LPS) could lead to β-cell apoptosis and dysfunction, while low-grade elevation of FFAs or LPS, which are more common in people with type 2 diabetes mellitus (T2DM) or obesity, have no obvious toxic effect on β-cells. Palmitate is a component closely related to metabolic disorders in FFAs. Recent studies have found that low-grade elevation of palmitate and LPS synergistically affects the sphingolipid signaling pathway by activating Toll-like receptor 4 (TLR4) and further enhances the expression of inflammatory cytokines in immune cells. Previous studies demonstrated that sphingolipids also played an important role in the occurrence and development of T2DM. This study aimed to investigate the synergistic effects of low-grade elevation of palmitate and LPS on viability, apoptosis and insulin secretion in the rat pancreatic β-cell line INS-1 or islets and the role of sphingolipids in this process. We showed that low-grade elevation of palmitate or LPS alone did not affect the viability, apoptosis, glucose-stimulated insulin secretion (GSIS) or intracellular insulin content of INS-1 cells or islets, while the combination of the two synergistically inhibited cell viability, induced apoptosis and decreased basal insulin secretion in INS-1 cells or islets. Treatment with palmitate and LPS markedly upregulated TLR4 protein expression and downregulated neutral ceramidase (NCDase) activity and protein expression. Additionally, low-grade elevation of palmitate and LPS synergistically induced a significant increase in ceramide and a decrease in sphingosine-1-phosphate. Blocking TLR4 signaling or overexpressing NCDase remarkably attenuated INS-1 cell injury induced by the combination of palmitate and LPS. However, inhibition of ceramide synthase did not ameliorate injury induced by palmitate and LPS. Overall, we show for the first time that low-grade elevation of palmitate and LPS synergistically induced β-cell damage by activating TLR4 signaling, inhibiting NCDase activity, and further modulating sphingolipid metabolism, which was different from a high concentration of palmitate-induced β-cell injury by promoting ceramide synthesis.

Protective effect of TAK242 blocking Toll-like receptor 4 pathway on septic myocardial injury and cardiac dysfunction

To investigate the role of Toll-like receptor 4 (TLR4) pathway on myocardial injury and cardiac dysfunction in septic rats. According to the random number table, 18 male Sprague-Dawley (SD) rats were divided into control group, lipopolysaccharide (LPS) group and TLR4 specific inhibitor TAK242 pretreatment group (TAK242+LPS group) with 6 rats in each group. The rat model of septic cardiac dysfunction was induced by intraperitoneal injection of LPS 15 mg/kg, and the control group was given the same amount of normal saline. The TAK242+LPS group was intraperitoneally given injection of TAK242 [it was injected intraperitoneally at a dose of 3 mg/kg and dissolved in 10% dimethyl sulfoxide (DMSO) and 90% corn oil according to the concentration of 0.2 g/L] 3 hours before LPS stimulation. The control group and LPS group were given the same amount of 10% DMSO and 90% corn oil. The cardiac function of rats in each group was examined by Doppler echocardiography 14 hours after injection of LPS. The blood of abdominal aorta was taken and the level of serum troponin (cTn) was measured by enzyme linked immunosorbent assay (ELISA). Myocardial tissue was harvested for hematoxylin-eosin (HE) staining, and the morphological changes of myocardial tissue were observed under light microscope. The mRNA expressions of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) in myocardial tissue were detected by real-time fluorescence quantitative polymerase chain reaction (qPCR). The protein expression of TLR4 in myocardial tissue was observed by immunohistochemical method. Western blotting was used to detect the levels of TLR4, nuclear factor-κB p65 (NF-κB p65) and its phosphorylation (p-NF-κB p65) in myocardial tissue. (1) The cardiac function and myocardial injury: Doppler echocardiography showed that the levels of left ventricular end-diastolic volume (LVEDV) and left ventricular end-systolic volume (LVESV) in the LPS group were significantly higher than those in the control group, while left ventricular ejection fraction (LVEF) and left ventricular shortened fraction (LVFS) were significantly lower than those in the control group. The degeneration, necrosis and inflammatory cell infiltration of cardiomyocytes were found with light microscope in the LPS group, and the levels of serum cTn were significantly higher than those in the control group, indicating that LPS-induced sepsis could cause cardiac dysfunction and myocardial injury. TAK242 blocking TLR4 pathway had a protective effect on cardiac function and myocardium during sepsis. LVEDV and LVESV in the TAK242+LPS group were significantly lower than those in the LPS group [LVEDV (μL): 71.25±21.16 vs. 118.01±11.89, LVESV (μL): 9.57±5.75 vs. 32.70±9.22, both P < 0.01]. LVEF and LVFS were significantly higher than those in the LPS group [LVEF: 0.868±0.075 vs. 0.722±0.095, LVFS: (59.88±8.46)% vs. (42.37±8.71)%, both P < 0.05]. Myocardial tissue injury was significantly reduced, and the serum cTn level was significantly lower than that in the LPS group (μg/L: 107.85±21.38 vs. 152.25±27.46, P < 0.05). (2) Inflammatory parameters: the results of qPCR, Western blotting and immunohistochemistry showed that the mRNA expressions of IL-6 and TNF-α, the expression of TLR4 protein and the p-NF-κB p65/NF-κB p65 ratio in the LPS group were significantly higher than those in the control group, indicating that LPS-induced sepsis could activate the inflammatory response mediated by TLR4/NF-κB pathway in the heart. However, blocking the TLR4 pathway by TAK242 could inhibit the TLR4/NF-κB pathway and reduce the myocardial inflammation in septic rats. The mRNA expressions of IL-6 and TNF-α, the expression of TLR4 protein and the p-NF-κB p65/NF-κB p65 ratio in the TAK242+LPS group were significantly lower than those in the LPS group [IL-6 mRNA (2-ΔΔCT): 10.44±3.30 vs. 107.50±29.48, TNF-α mRNA (2-ΔΔCT): 2.38±0.68 vs. 3.77±0.56, TLR4 protein (TLR4/GAPDH): 0.39±0.01 vs. 0.58±0.04, p-NF-κB p65/NF-κB p65 ratio: 1.21±0.11 vs. 2.10±0.18, all P < 0.05]. TAK242 can protect LPS-induced cardiac dysfunction and myocardial injury by blocking the TLR4 mediated inflammatory response.

Spinal cord Toll like receptor 4 and its co-stimulatory molecule heat shock protein 90 may parti-cipate in electroacupuncture analgesia in rats with chronic neuropathic pain

To observe the effect of electroacupuncture (EA) on the expression of Toll like receptor 4(TLR4)and heat shock protein 90(HSP90) in the spinal cord of rats with chronic constriction injury (CCI) of sciatic nerve, so as to explore the mechanism of spinal cord TLR4 and HSP90 in alleviating chronic neuropathic pain by EA. Male Wistar rats were randomized into control, model, EA, HSP90 inhibitor (inhibitor) and EA+ inhibitor groups (n=10 in each group). The neuropathic pain model was established by ligature of the right sciatic nerve to induce CCI. EA (1 mA，2 Hz/15 Hz)was applied at bilateral "Zusanli"(ST36) and "Yanglingquan"(GB34) for 30 min, once daily for 5 days. Rats of the inhibitor and EA+inhibitor groups were given a subcutaneous injection of HSP90 inhibitor geldanamycin (50 μg/kg) at the neck before daily EA. The paw withdrawal latency (PWL) of the bilateral hind-limbs was detected by using an algesia-detector. The contents of interleukin 1β (IL-1β) and tumor necrosis factor α (TNF-α) in the lumbar spinal cord (L2-L4) tissue were detected by enzyme-linked immunosorbent assay. The relative expression levels of HSP90 and TLR4 proteins in the lumbar spinal cord (L2-L4) were detected using Western blot and immunofluorescence double labeling, respectively. Following CCI, a strong thermal hyperalgesia, an apparent up-regulation of expression of HSP90 and TLR4 proteins and TLR4 in microglia, and increasing levels of IL-1β and TNF-α in the spinal cord were induced in the model group relevant to the control group (P<0.01，P<0.05). Five sessions of EA intervention or inhibitor injection significantly attenuated hyperalgesia, reversed the increase of IL-1β and TNF-α, and down-regulated the expression of TLR4 in microglia (P<0.05). Compared with the model group, the expression of HSP90 was further increased (P<0.05), and those of TLR4 in microglia and neurons were significantly decreased and increased, respectively in the EA group (P<0.05). Compared with the EA group, the levels of PWLD,TLR4 and HSP90 expression, and the proportions of neuronal nuclei antigen（NeuN） and TLR4, and ionized calcium binding adapter molecule （Iba1） and TLR4 co-expressed cells were significantly decreased in the inhibitor group and EA+inhibitor group (P<0.05). The proportion of NeuN and TLR4 co-expression cells in the EA+inhibitor group was significantly higher than that of the inhibitor group (P<0.05). EA stimulation of ST36 and GB34 can alleviate thermal hyperalgesia in CCI rats, which is closely associated with its effect in regulating the expression of TLR4 in the spinal cord neurons and microglia. HSP90 in the spinal cord may be a co-stimulatory molecule for EA induced relief of neuropathic pain by regulating TLR4.

Insight Cross-talk between p53 and Toll-like Receptor

Toll-like receptors (TLR) are one of the most-studied receptors for their role in innate immunity. TLRs are reported to binds with conserved pathogen-associated molecular patterns (PAMPS). TLRs and PAMPS interaction leads to several downstream proteins' activation, which further signaled to the various transcription factors. Moreover, these transcription factors play an important role in synthesizing proteins that control cellular immunity. Various TLR proteins have been reported in humans as well several other organisms. Studies show that apart from inducing innate immunity, TLRs have also played an important role in the induction of many proteins, and protein networks associated with initiation apoptosis and cancer prevention. P53 is one of the most important and widely studied proteins. Moreover, various experimental studies suggest that p53 has an important role as tumor suppressor. It is reported that more than 50% of cancerous growth are associated with the mutation of p53. It acts as transcription activator for several proteins that are mostly associated with glycolysis, cell cycle, cell differentiation, apoptosis and cancer. In the present review, we present an insight cross-talk between p53 and Toll-like receptor. In addition, the well-characterized role of p53 in the regulation of the immune system is studied, which would provide a new insight to the broad understanding of p53 role in human biology. Moreover, the association of the p53 and TLRs can lead to therapeutic interventions.

Identification of Core Genes of Toll-like Receptor Pathway from Lymantria dispar and Induced Expression upon Immune Stimulant.

Simple SummaryThe gypsy moth, Lymantria dispar is one of the main forest defoliators worldwide. The baculovirus, Lymantria dispar multiple nucleopolyhedrovirus (LdMNPV), can naturally control this pest and is safe to non-target organisms. However, Toll-like receptor (TLR) signaling pathway, which plays a critical role in innate immunity both in vertebrates and invertebrates, and its underlying immune mechanism against LdMNPV invasion in L. dispar have not been investigated. In this study, eleven TLRs and five downstream TLR pathway components of L. dispar were identified. All of these proteins comprised typical domain architecture. Primary and tertiary structure analysis revealed that Toll/interleukin-1 receptor (TIR) domains of TLRs from L. dispar were conserved during evolution. Expression analysis showed that several TLRs and all identified downstream genes of TLR pathway in L. dispar were significantly up-regulated in response to LdMNPV infection, implying that the TLR pathway of L. dispar was activated and may be involved in L. dispar innate immunity against LdMNPV infection. Taken together, this research contributed to the clarification of innate immunity in L. dispar.The gypsy moth, Lymantria dispar, is a polyphagous forest pest worldwide. The baculovirus, Lymantria dispar multiple nucleopolyhedrovirus (LdMNPV) is a natural pathogen of L. dispar. The Toll-like receptors (TLR) pathway plays a crucial role in both innate and adaptive immunity in animals. However, The TLR pathway and its underlying immune mechanism against baculovirus in L. dispar have not been explored. In this study, eleven TLRs and five downstream TLR pathway components were identified and characterized from L. dispar. Structural analysis indicated that intracellular Toll/interleukin-1 receptor (TIR) domains of LdTLRs and LdMyD88 contained three conserved motifs, and the 3D structures of TIR domains of LdTLRs possessed similar patterns in components arrangement and spatial conformation. The TLR proteins of L. dispar were placed into five monophyletic groups based on the phylogenetic analysis. LdTLR1, 2, 5, 6, 7, 8 and all identified downstream TLR pathway factors were highly induced upon LdMNPV infection, indicating that the TLR pathway of L. dispar was activated and might play a role in the immune response to LdMNPV infection. Collectively, these results help elucidate the crucial role of the TLR pathway in the immune response of L. dispar against LdMNPV, and offer a foundation for further understanding of innate immunity of the pest.

MiRNA-489-3p Improves Sepsis-Induced Lung Injury by Regulating Toll-Like Receptor 4 (TLR4) Signaling Pathway

Aim: To discuss miRNA-489-3p in sepsis-induced lung injury. Materials and methods: Using NR-8383 as research cell in our study, and using LPS stimulation to sepsis induced lung injury vitro model. Measuring cell proliferation by MTS assay; using Elisa assay to measure IL-1β, IL-6 and TNF-α concentration; apoptosis cell number and apoptosis rate were evaluated using TUNEL and flow cytometry; gene and protein were measured by RT-PCR and WB assay; measuring p-NF-κB(p65) nuclear volume by Immunofluorescence (IF); using Luciferase reporter assay to analysis miRNA-489-3p and TLR4 correlation. Results: Cell proliferation rate significantly down-regulated (P &lt; 0.001), apoptosis cell number and apoptosis rate significantly increased (P &lt; 0.001); IL-1β, IL-6 and TNF-α concentrations significantly up-regulated (P &lt; 0.001); TLR4 and MyD88 gene and protein significantly increased (P &lt; 0.001), NF-κB(p65) mRNA and p-NF-κB(p65) protein and nuclear volume significantly increased (P &lt; 0.001). However, with miRNA-489-3p supplement, the cell proliferation rate, apoptosis cell number and apoptosis rate were significantly improved (P &lt; 0.001, respectively) via TLR4, MyD88 and NF-κB(p65) mRNA and protein significantly depressing (P &lt; 0.001, respectively). By LUC assay, miRNA-489-3p could target to TLR4 in NR-8383 cell. Conclusion: miRNA-489-3p overexpression had effect to improve sepsis induced lung injury via regulation TLR4/MyD88/NF-κB(p65).

Gut Leakage Markers in Response to Strenuous Exercise in Patients with Suspected Coronary Artery Disease.

Elevated levels of gut leakage markers have been shown after strenuous exercise in healthy individuals. Any association between a temporary increase in these markers and the presence of coronary artery disease (CAD) is unknown. We therefore aimed to explore circulating gut leakage markers in response to a bout of strenuous exercise in patients with symptoms of CAD. Patients referred to exercise stress testing due to symptoms of CAD were included (n = 287). A maximal exercise ECG stress test was performed and venous blood samples were drawn at rest and within five minutes after, for analysis of soluble cluster of differentiation 14 (sCD14), lipopolysaccharide-binding protein (LBP), intestinal fatty-acid binding protein (I-FABP), lipopolysaccharide (LPS) and gene expression of toll-like receptor 4 (TLR4) in circulating leukocytes. Patients then underwent coronary angiography. LPS, LBP and sCD14 increased significantly after strenuous exercise in patients with symptoms of CAD, suggesting that even short bouts of vigorous exercise are associated with gut leakage. The gene expression of TLR4 decreased significantly after exercise, possibly as a negative feedback to the increase in LPS. There were no differences in exercise-induced changes between the groups of CAD, suggesting gut leakage to be independent of the presence of CAD.

Astragaloside prevents UV-induced keratinocyte injury by regulating TLR4/NF-κB pathway.

Ultraviolet (UV) radiation is a key risk factor of environment to contribute photoaging and skin cancer through production of reactive oxygen species (ROS) and inflammatory responses. Astragaloside IV (AS-IV) is an active component from Astragalus membranaceus, and shows various pharmacological effects on inflammation, oxidative stress and apoptosis. However, whether AS-IV shows protective effect on UVB-induced injury in epidermal keratinocytes remain unknown. To explored the effects of AS-IV on UVB-induced oxidative injury and inflammatory response in human epidermal keratinocytes. HaCaT keratinocytes were exposed to UVB irradiation, followed by AS-IV incubation. The cell viability, intracellular ROS level, oxidative stress, and apoptosis were determined. The regulatory effects of AS-IV on toll-like receptor 4 (TLR4) pathway in UVB-exposed HaCaT cells were also investigated. Astragaloside IV pretreatment (10, 25, 50, 100 and 150 μM) increased cell viability in UVB-exposed HaCaT cells. AS-IV (50 μM) significantly reduced intracellular ROS level and lipid oxidation product malondialdehyde (MDA) content, and increased a ROS-scavenging enzyme superoxide dismutase (SOD) in HaCaT cells with UVB irradiation. In addition, AS-IV pretreatment suppressed apoptosis, increased Bax protein, caspase-3 and 9, and decreased BCL-2 protein in contrast to HaCaT cells with UVB-irradiation. AS-IV suppressed proinflammatory cytokine production, inhibited TLR4 and its downstream signaling molecules NF-κB, iNOS and cyclooxygenase-2 (COX-2) protein expression. We also found that the effects of AS-IV on cell viability and TLR4 expression was reversed by NAC. The protective of AS-IV on UVB-induced damage and TLR4 expression was dependent on ROS, as the increase in viability and decrease in TLR4 protein by AS-IV was significantly attenuated by ROS scavenger NAC (1 mM). Astragaloside IV prevent UVB-induced oxidative damage and inflammation by inhibiting TLR4 expression.

Effect of transcutaneous auricular vagus nerve stimulation on the expression of TLR4、MyD88、IL-18 protein in the prefrontal cortex of depression rats

To observe the effect of transcutaneous auricular vagus nerve stimulation (taVNS) on the depressive behavior in depression rats, so as to explore its mechanism underlying improvement of depression. A total of 24 male Sprague Dawley rats were randomly divided into normal, depression model, taVNS, tnVNS (transcutaneous auricular none-vagus nerve stimulaton) groups (n=6 in each group). The depression model was established by chronic unpredictable mild stimulation combined with solitary raising for 35 consecutive days. After 14 days modeling, transcutaneous electrostimulation (2 mA, 2 Hz/15 Hz) was applied to auricular concha or auricular margin, respectively. Each intervention was conducted for 30 minutes, once daily for 21 days. The depression-like behavior was evaluated by forced swimming immobility time and body weight. The expression levels of Toll-like receptor 4 (TLR4), myeloid differentiation factor 88 (MyD88) and interleukin-18 (IL-18) protein in the prefrontal cortex were detected by Western blot. Following modeling, the increase amount of body weight was decreased, the forced swimming immobility time and expression TLR4, MyD88 and IL-18 protein in the prefrontal cortex were increased in the model group than those in the normal group (P<0.01). Following the treatment and compared with the model group, the increase amount of body weight in the taVNS group was obviously increased (P<0.05), the swimming immobility time and the expression of TLR4, MyD88, IL-18 protein in the taVNS and tnVNS groups were significantly decreased (P<0.01). TaVNS is able to improve depression in depression rats, which is probably related to its effect in inhibiting inflammatory response of TLR4/MyD88 signaling pathway in prefrontal cortex.

Toll-Like Receptor 9-Mediated Neuronal Innate Immune Reaction Is Associated with Initiating a Pro-Regenerative State in Neurons of the Dorsal Root Ganglia Non-Associated with Sciatic Nerve Lesion

One of the changes brought about by Wallerian degeneration distal to nerve injury is disintegration of axonal mitochondria and consequent leakage of mitochondrial DNA (mtDNA)—the natural ligand for the toll-like receptor 9 (TLR9). RT-PCR and immunohistochemical or Western blot analyses were used to detect TLR9 mRNA and protein respectively in the lumbar (L4-L5) and cervical (C7-C8) dorsal root ganglia (DRG) ipsilateral and contralateral to a sterile unilateral sciatic nerve compression or transection. The unilateral sciatic nerve lesions led to bilateral increases in levels of both TLR9 mRNA and protein not only in the lumbar but also in the remote cervical DRG compared with naive or sham-operated controls. This upregulation of TLR9 was linked to activation of the Nuclear Factor kappa B (NFκB) and nuclear translocation of the Signal Transducer and Activator of Transcription 3 (STAT3), implying innate neuronal immune reaction and a pro-regenerative state in uninjured primary sensory neurons of the cervical DRG. The relationship of TLR9 to the induction of a pro-regenerative state in the cervical DRG neurons was confirmed by the shorter lengths of regenerated axons distal to ulnar nerve crush following a previous sciatic nerve lesion and intrathecal chloroquine injection compared with control rats. The results suggest that a systemic innate immune reaction not only triggers the regenerative state of axotomized DRG neurons but also induces a pro-regenerative state further along the neural axis after unilateral nerve injury.