On the Impairment of Stress-Induced Changes in Triglyceride Levels via a Sub-Toxic Dose of Unmethylated Cytidine Phosphate Guanosine Oligodinucleotide (a Toll-Like Receptor 9 Ligand)

Changes in lipid metabolism have been implicated in protection against infectious diseases. In the first experiment of this study, we measured clinical lipid parameters in a murine model where the unmethylated cytidine phosphate guanosine (CpG) oligodinucleotide (ODN1826), a Toll-like receptor 9 (TLR9) agonist was administered in combination with D-galactosamine (GalN) that caused relatively liver-specific inflammation and toxicity. In the control mice group injected with phosphate-buffered saline (PBS) (acute psychological stress model associated with blood sampling), the serum triglyceride (TG) levels showed a rapid decrease followed by a rebound at 24 h as we have recently reported. However, such a TG rebound was impaired in the CpG/GalN- and solely CpG-treated groups of mice despite an absence of liver injury based on serum alanine aminotransferase levels in the latter group. Thus, the stress-associated serum TG rebound was abrogated by the injection of a sub-hepatotoxic CpG dose. In the second experiment, we simply measured the hepatic CD36 and SACRB1 (the gene for scavenger receptor B1 (SR-B1)) transcripts after the i.p. administration of PBS, CpG or CpG/GalN. There was a remarkable elevation of hepatic CD36 transcript expression in both the CpG- and CpG/GalN-treated mice at 8 h post-CpG injection whereas the increase in the PBS-treated mice was slower than the former two groups, suggesting that hepatic CD36 transcript expression is more pronounced in the combined stress models than under psychological stress alone. The individual mice data showed that the increase in CD36 expression was accompanied by a reduction in SCARB1 mRNA, showing reciprocal regulation between these two genes. Together with our previously reported findings, these data suggest that, in a murine model combining psychological stress with TLR-triggered hepatic inflammation, the psychological stress facilitates liver uptake of plasma TG (and its components fatty acids), but the subsequent re-esterification and/or release of TG-rich lipoproteins from the liver is impaired due to the concomitant TLR-signaling. We hypothesize that lipid metabolism during acute stress shifts toward an elevated hepatic uptake of lipids due to concomitant TLR signaling, facilitating the clearance of bacterial lipids by the liver.

The Role of Toll-Like Receptors and Nuclear Factor κB p65 Protein in the Pathogenesis of Otitis Media

The role of Toll-like receptor 4 (TLR4) and nuclear factor κB p65 (NF-κB p65) proteins in the pathogenesis of otitis media is explored. In recent years, the incidence of otitis media has been rising globally, becoming a significant threat to human health. More and more studies have found that Toll-like receptor 4 (TLR4), as a member of the Toll-like receptor family, can promote the generation of inflammatory factors and is closely related to the body’s immune response and inflammatory response. Nuclear factor-κB p65 (NF-κB p65) is a nuclear transcription factor that can interact with various cytokines, growth factors, and apoptotic factors, participating in processes such as oxidative stress, apoptosis, and inflammation in the body [1]. This article elaborates on the structure, function, and signaling pathways of TLR4 and NF-κB p65 proteins in the pathogenesis of otitis media, aiming to provide more precise targets and better therapeutic efficacy for the diagnosis and treatment of otitis media. The role of inflammation in disease.

Expression and Implication of Toll-like Receptors TLR2,TLR4 and TLR9 in Colonic Mucosa of Patients with Ulcerative Colitis

Toll-like receptors （TLRs） family may play important roles in inflammatory bowel dis- ease. This study examined the expression of TLR2, TLR4 and TLR9 in the colonic tissues of patients with ulcerative colitis 0AC） and explored their roles in the pathogenesis of UC. Colonic biQpsies were taken from the colon of 30 patients with mild or moderate UC （at active phase） and 10 healthy con- trois during colonoscopy. TLR2, TLR4 and TLR9 protein expression levels were immunohisto- chemically detected. The mRNA expression levels of TLR2, TLR4 and TLR9 were assessed by re- verse transcription polymerase chain reaction （RT-PCR）. The disease activity index （DAI）, colono- scopic and histologic grades and fecal microbial flora were determined. Histological examination showed that the intestinal mucous membrane of UC patients underwent acute inflammation changes. Immunohistochemistry exhibited that the expression levels of TLR2, TLR4 and TLR9 in colon epi- thelia and inflammatory cells were higher in UC patients than in control group （P〈0.01）. The mRNA expression levels of TLR2, TLR4 and TLR9 were increased in UC patients but were not detected in the normal controls. Expression levels ofTLR2, TLR4 and TLR9 were positively correlated, and bore close correlation with DAI, colonoscopic and histologic grades and fecal microbial flora. An impor- tant mechanism of UC might be that abnormal activation of mucosal immunity by intestinal dysbac- teriosis caused dysregulation of TLRS that mediates innate immunity.

Effect of Ligands to Toll-Like Receptors (TLR) 3, 7 and 9 on Mice Infected with Mouse Hepatitis Virus A59

Mice infected with mouse hepatitis virus A59 (MHV-A59), an enveloped, positive-strand RNA Co-ronavirus, induce hepatitis, thymus involution, IgG2a-restricted hypergammaglobulinaemia, transaminase release and autoantibodies (autoAb) to liver and kidney fumarylacetoacetate hy-drolase (FAH). Since Toll-like receptors (TLR) play a central role in innate immunity, we explored the effects of TLR3, 7 and 9 stimulation on MHV mouse infection. Thus, the animals were treated with Poly (I:C), Loxoribine and CpG, the respective TLR ligands. MHV-infected mice inoculated with Poly (I:C) had significant lower levels of plasma transaminases and Ig, anti-MHV Ab, and uric acid than MHV-infected animals, whereas autoAb to kidney tissue were observed. Loxoribine only produced a slight decrease of uric acid levels and serum Ig. CpG showed deleterious effects on MHV-infected mice, since survival of animals dramatically dropped to about 10%. AutoAb to murine tissues and uric acid release were not affected, whereas transaminases and anti-MHV Ab were slightly elevated. Besides, CpG administration produced a decrease of the high levels of serum Ig induced by the virus. Therefore, results indicated that TLR3 stimulation appeared to protect the animals against the viral infection, whereas CpG aggravated its signs. Loxoribine, the TLR7 ligand, did not show major effects.

Molecular Assessment of Non-Muscle Invasive and Muscle Invasive Bladder Tumors: Mapping of Putative Urothelial Stem Cells and Toll-Like Receptors (TLR) Signaling

Purpose: The main objectives of this study were to characterize and compare the urothelial stem cells (healthy and cancer cells) and TLRs features in the urinary bladder of men without lesionsand with non-muscle-invasive and muscle invasive urothelial tumors. Materials and Methods: Thirty samples of the urinary bladder of 50 to 80-year-old men, with and without diagnosis of malignant urothelial lesions were used. The 30 samples were divided into 3 groups (n = 10 per group): Normal Group;Non-Muscle Invasive Bladder Cancer Group;Muscle Invasive Bladder Cancer Group. The samples were histopathologically and immunohistochemically analyzed. The study was conducted at teaching Hospital of the University of Campinas (UNICAMP). Results: The CD44 and CD133 immunoreactivities were significantly intense in the muscle-invasive cancer group when compared to the other groups. The ABCG2 biomarker demonstrated intense immunoreactivities in both non-muscle and muscle invasive groups, and absent immunoreactivity in the normal group. All groups showed weak CD117 immunoreactivity. Putative Healthy Stem Cells (CD44/CD133/ CD117+) occurred in all groups. Putative Cancer Stem Cells (CD44/CD133/ABCG2+) only occurred in the non-muscle and muscle invasive cancer groups. TLR2 immunoreactivity was significantly lower in the non-muscle invasive cancer group and absent in the muscle invasive cancer group. TLR4 immunoreactivity was significantly lower in both cancer groups. Conclusions: This study leads us to the conclusion that putative cancer stem cell occurrence was sensitive to the decreased in TLR2 and TLR4 immunoreactivities. Also, TLR2 and TLR4 demonstrated their involvement in the regulation of the different biomarkers for putative healthy and cancer urothelial stem cells, probably acting as negative regulators of urothelial carcinogenesis. Taken together data obtained suggest that use of TLRs agonists could be a promising alternative for the treatment of non-muscle and muscle invasive bladder tumors.

广谱模式识别分子Toll-like receptor 2的研究进展

TLR-2（Toll-like receptor 2,TLR-2）是哺乳动物TLRs（Toll-like receptors,TLRs）家族的一员,作为细胞表面的天然受体蛋白,主要参与病原微生物产物的识别及炎症信号传导,介导天然抗感染兔疫;最近又发现其参与机体对非感染因子所致炎性组织损伤的识别。通过对TLR-2参与的识别和细胞内信号传导机制的研究,可为深入探讨抵御微生物感染的机制、对自身正常与非正常组织的识别提供新的思路。

人Toll-like receptor 2配基模拟肽的初步研究

TLR-2(Toll-likereceptor2)是介导天然免疫的重要模式识别分子,可参与识别多种病原体及其产物.为探索被TLR-2所识别配基的结构共性,以真核细胞表达的人TLR-2胞外段蛋白(A26￣T588)为钓饵筛选噬菌体12肽库,获得一高度保守的阳性噬菌体克隆P12-1,实验发现P12-1可与不同形式的TLR-2胞外段结合,并且可刺激细胞分泌TNFα,提示P12-1可能模拟TLR-2配基的结构与生物学活性.

Toll-like receptor激动剂耐受分子机制和疟原虫慢性感染

小剂量LPS预刺激可引起内毒素耐受,能提高小鼠在致死剂量LPS再次刺激后的存活率,其机制可能与铎样受体TLR(Toll-like receptor)4信号通路的下调有关。近年来的研究发现,其他TLR激动剂同样可以引起宿主对相应TLR激动剂和LPS的耐受,后者称为交叉耐受(cross tolerance),而且疟原虫慢性感染同样能诱导类似TLR激动剂耐受的现象,因此,研究TLR激动剂耐受分子机制有助于脓毒血症预防和对慢性感染机制的理解。

Activation of Toll-like receptors signaling in non-small cell lung cancer cell line induced by tumor-associated macrophages

Background： Inflammation is often linked with the progress and poor outcome of lung cancer. The understanding of the relationship between tumor-associated macrophages （TAMs） and lung cancer cells involves in the underlying mechanism of inflammatory cytokine production. Toll-like receptors （TLRs） are engaged in promoting the production of pro-inflammatory cytokines and play an important role in tumor immunology. Methods： To investigate the mechanisms by which TAMs influence the production of pro-inflammatory cytoldnes in lung cancer cells, we established an in vitro coculture system using TAMs and human non- small cell lung cancer （NSCLC） cell line SPC-A1. Levels of interleukin （IL）-113, IL-6 and IL-8 in SPC-A1 were evaluated by RT-PCR and cytometric bead array assay after being cocultured with TAMs. Expression changes of TLRs and TLRs signaling pathway proteins in SPC-Al were further confirmed by RT-PCR and western blot. The level changes of IL-1β, IL-6 and IL-8 in SPC-Al were also detected after the stimulation of TLRs agonists. Results： We found that the phenotype markers of TAMs were highly expressed after stimulating human monocyte cell line THP-1 by phorbol-12-myristate-β-acetate （PMA）. Higher mRNA and supernate secretion levels of IL-1β, IL-6 and IL-8 were detected in SPC-A1 after being eocultured with TAMs. We also found that TLR1, TLR6 and TLR7 were up-regulated in SPC-A1 in the coculture system with TAMs. Meanwhile, TLRs signaling pathway proteins were also significantly activated. Moreover, pre-treatment with agonist ligands for TLR1, TLR6 and TLR7 could dramatically promote inductions of IL-1β, IL-6 and IL-8. Conclusions： These findings demonstrated that TAMs may enhance IL-1β, IL-6 and IL-8 expressions via TLRs signaling pathway. We conclude that TAMs contribute to maintain the inflammation microenvironment and ultimately promote the development and progression of lung cancer.

Expressions of Toll-like receptors 3,4,7,and 9 in cervical lesions and their correlation with HPV16 infection in Uighur women

Recent findings show that Toll-like receptors(TLRs) expressed in immune cells play a crucial role in the innate immune response and the subsequent induction of adaptive immune responses against microbial infection on tissue injury.Furthermore,expression of TLRs in cancer cells is associated with tumor proliferation and invasion.To explore the role of TLRs expression in cervical carcinogenesis in Uighur women,we detected the expressions of TLR3,TLR4,TLR7,and TLR9 in 25 normal cervical tissues,64 cervical intraepithelial neoplasia(CIN) tissues,and 63 cervical squamous cell carcinoma(CSCC) tissues using immunohistochemical staining,as well as human papillomavirus type 16(HPV16) infection using PCR.All samples used in this study were from Xinjiang Uighur women.We found the expression levels of TLR4,TLR7,and TLR9 were significantly higher in CIN and CSCC than in normal controls(P < 0.05).Up-regulation of TLR4 and TLR7 were correlated with tumor differentiation but not FIGO stage or lymph node metastasis(P > 0.05).Up-regulation of TLR9 was correlated with lymph node metastasis(P < 0.05) but not tumor differentiation or FIGO stage(P > 0.05).We also analyzed the correlation between the expressions of TLRs and HPV16 infection and found that the expressions of TLR4 and TLR9 significantly correlated with HPV16 infection in CIN(r = 7.434,P = 0.006;r = 7.123,P = 0.008) and CSCC(r = 6.423,P = 0.001;r = 8.478,P = 0.004),whereas the expression of TLR3 was not significantly different in any of the three groups and had no significant correlation with HPV16 infection.Our results suggest that high expression of TLR4,TLR7,and TLR9 may play important roles in the development and progression of CIN and CSCC in Uighur women,and the expressions of TLR4 and TLR9 can be up-regulated by HPV16 infection.

Novel role of toll-like receptors in Helicobacter pylori-induced gastric malignancy

Helicobacter pylori(H.pylori)infects the human stomach during infancy and develops into chronic activeinflammation.The majority of H.pylori tend to colonize within the mucous gel layer of the stomach.Thestomach lacks its own immune function,thus innateimmunity as the first line of defense is vital for specificimmunity against H.pylori.We review recent discoveries in the pathophysiologic roles of toll-like receptors(TLRs),mainly TLR2 and TLR4,in H.pylori-induced inflammation.In addition,the TLR pathways activated byH.pylori-induced inflammation have been shown to beclosely associated not only with gastric carcinogenesis,but also with formation of the tumor microenvironmentthrough the production of pro-inflammatory cytokines,chemokines,and reactive oxygen species.Althoughthe correlation between single nucleotide polymorphisms of TLRs and gastric cancer risk remains unclear,a recent study demonstrated that STAT3-driven upregulation of TLR2 might promote gastric tumorigenesis independent of inflammation.Further research onthe regulation of TLRs in H.pylori-associated gastriccarcinogenesis will uncover diagnostic/predictive biomarkers and therapeutic targets for gastric cancer.

Expression and Immune Effect of Toll-Like Receptor 4 in Human Trophoblast Cells

This study investigated the expression and immune effect of TLR4 in human trophoblast cells. The expression level of TLR4 mRNA in normal and LPS-stimulated human term trophoblast cells （1 mg/L LPS, 12 h） was detected by RT-PCR. In LPS-stimulated human term trophoblast cells of TLR4-blocked group and non-TLR4-blocked group, and normal term trophoblast cells of blank control group, apoptosis rate was measured by flow cytometry （FCM）, and the level of TNF-α determined by using enzyme linked immunosorbent assay （ELISA） respectively. RT-PCR results showed that the expression level of TLR4 mRNA in LPS-stimulated human trophoblast cells was significantly higher than that in normal cells （P〈0.01）. FCM revealed that there was significant difference in apoptosis rate of LPS-stimulated human term trophoblast cells between TLR4-blocked group and non-TLR4-blocked group （P〈0.05）, or between TLR4 antibody-blocked group and blank control group. ELISA indicated that the level of TNF-α in LPS-stimulated human trophoblast cells also had statistical differences between TLR4 antibody-blocked group and non-TLR4 antibody-blocked group （P〈0.05）. Our results suggest that TLR4 plays an important role in the immunological mechanism of apoptosis and secretion of TNF-α of human term trophoblast cells stimulated by LPS.

Toll-like receptor 4-mediated signaling participates in apoptosis of hippocampal neurons

The phosphatidylinositol 3 kinase （PI3K）/protein kinase B （AKT） signaling pathway is considered important for cell survival and has been shown to mediate various anti-apoptotic biological effects. This study explored the role of the Toll-like receptor 4 （TLR4）-mediated PI3K/AKT-glycogen syn-thase kinase 3β （GSK-3β） signaling pathways in lipopolysaccharide-induced apoptosis in a primary culture of hippocampal neurons. Results demonstrated that the apoptotic ratio of hippocampal neurons stimulated by lipopolysaccharide was significantly higher compared with the control group. Both the expression of P-AKTser473 and P-GSK-3βSserg in hippocampal neurons stimulated by lipopolysaccharide decreased compared with the control, while the level of active Caspase-3 and the ratio of Bax/Bcl-2 were significantly increased. The level of active Caspase-3 and the ratio of Bax/Bcl-2 in hippocampal neurons treated with TLR4 antibody or the GSK-3β inhibitor, LiCl, de-creased before intervention with lipopolysaccharide, but increased after treatment with the AKT in-hibitor, LY294002. These findings suggest that the TLR4-PI3K/AKT-GSKβ signaling pathway may be involved in lipopolysaccharide-induced apoptosis of hippocampal neurons.

Toll样受体2(TLR2)与结核分枝杆菌感染的相关研究进展

Toll样受体2(TLR2)是白细胞表面表达的一种模式识别受体,已发现多种配体可以激动或抑制TLR2的活化,进而调控免疫细胞的炎症和凋亡状态。结核分枝杆菌(MTB)通常寄生在巨噬细胞中,但MTB感染机体后,包括巨噬细胞在内的多种免疫细胞表面的TLR2都可与其相互作用,释放细胞因子,影响MTB在体内的状态和增殖。在分子层面,TLR2的多态性有待更多探索,目前研究的大部分TLR2的多态性被认为与MTB的易感性无关。文中总结了TLR2与配体、感染后免疫调节活动、多态性与MTB易感性等方面的研究进展。

Science Letters:A synthetic Toll-like receptor 2 ligand decreases allergic immune responses in a mouse rhinitis model sensitized to mite allergen

It has been proposed that activation of Toll-like receptors （TLRs） plays crucial roles in the polarization of adaptive immune responses. A synthetic Toll-like receptor 2 （TLR2） ligand, Pam3CSK4, has been reported to modulate the balance of Th1/Th2 responses. We evaluated the modulation effect of Pam3CSK4 on allergic immune response in a mouse rhinitis model sensitized to house dust mite allergen （HDM）. Mice were sensitized and challenged with Dermatophagoidesfarinae allergen （Der f）, and then the allergic mice were treated by Pam3CSK4. Nasal allergic symptoms and eosinophils were scored. Der f-specific cytokine responses were examined in the splenocytes and bronchoalveolar lavage fluid （BALF）. Serum level of total IgE was also detected. After establishing a mouse allergic rhinitis model with HDM, we have showed that Pam3CSK4 treatment not only ameliorated the nasal allergic symptoms remarkably but also decreased the eosinophils and total inflammation cells in BALF significantly. Analysis of cytokine profile found that IFN-7 released from either BALF or stimulated splenocytes increased markedly in Pam3CSK4-treated mice, while IL-13 decreased significantly. Moreover, serum level of total IgE was significantly lower in Pam3CSK4-treated mice than in the untreated. Thus, in an allergic rhinitis mouse model developed with HDM, Pam3CSK4 was shown to exhibit an antiallergic effect, indicating its potential application in allergic diseases.

Toll-like receptor signaling in colorectal cancer:carcinogenesis to cancer therapy

Toll-like receptors (TLRs) are germ line encoded innate immune sensors that recognize conserved microbial structures and host alarmins, and signal expression of major histocompatibility complex proteins, costimulatory molecules, and inflammatory mediators by macrophages, neutrophils, dendritic cells, and other cell types. These protein receptors are characterized by their ability to respond to invading pathogens promptly by recognizing particular TLR ligands, including flagellin and lipopolysaccharide of bacteria, nucleic acids derived from viruses, and zymosan of fungi. There are 2 major TLR pathways; one is mediated by myeloid differentiation factor 88 (MYD88) adaptor proteins, and the other is independent of MYD88. The MYD88-dependent pathway involves early-phase activation of nuclear factor of kappa light polypeptide gene enhancer in B-cells 1 (NF-&#x003ba;B1) and all the TLRs, except TLR3, have been shown to activate this pathway. TLR3 and TLR4 act via MYD88-independent pathways with delayed activation of NF-&#x003ba;B signaling. TLRs play a vital role in activating immune responses. TLRs have been shown to mediate inflammatory responses and maintain epithelial barrier homeostasis, and are highly likely to be involved in the activation of a number of pathways following cancer therapy. Colorectal cancer (CRC) is one of the most common cancers, and accounts for almost half a million deaths annually worldwide. Inflammation is considered a risk factor for many common malignancies including cancers of the colorectum. The key molecules involved in inflammation-driven carcinogenesis include TLRs. As sensors of cell death and tissue remodeling, TLRs may have a universal role in cancer; stimulation of TLRs to activate the innate immune system has been a legitimate therapeutic strategy for some years. TLRs 3/4/7/8/9 are all validated targets for cancer therapy, and a number of companies are developing agonists and vaccine adjuvants. On the other hand, antagonists may favor inhibition of signaling responsible for autoimmune responses. In this paper, we review TLR signaling in CRC from carcinogenesis to cancer therapy.

Betaine inhibits Toll-like receptor 4 expression in rats with ethanol-induced liver injury

AIM:To test whether ethanol feeding could induce Toll-like receptor 4(TLR4)responses,assess the hepatoprotective effect of betaine and its inhibitive effect on TLR4 in animal models of alcoholic liver injury.METHODS:Forty-eight female Sprague-Dawley rats were randomly divided into four groups as control,model,low and high dose betaine groups.Except control group,all rats were fed with high fat-containing diet plus ethanol and fish oil gavages for 8 wk.Betaine was administered intragastrically after exposure of ethanol for 4 wk.The changes of liver histology were examined.The expression of TLR4 mRNA and protein was detected by RT-PCR and Western blotting,respectively.The serum aminotransferase activity alanine transarninase(ALT),aspartate aminotransferase(AST),serum endotoxin,and liver inflammatory factors tumor necrosis factor-α(TNF-α),interferon-γ(IFN-γ),interleukin-18(IL-18)were also assayed.RESULTS:Compared with control group,rats of model group developed marked liver injury,accompanied by an increase of ALT(159.41±7.74 U/L vs 59.47± 2.34 U/L,P<0.0001),AST(248.25±1.40 U/L vs 116.89±3.48 U/L,P<0.0001),endotoxin(135.37± 30.17 ng/L vs 44.15±7.54 ng/L,P<0.0001),TNF-α(20.81±8.58 pg/mL vs 9.34±2.57 pg/mL,P=0.0003),IFN-γ(30.18±7.60 pg/mL vs 16.86±9.49 pg/mL,P= 0.0039)and IL-18(40.99±8.25 pg/mL vs 19.73±9.31 pg/mL,P=0.0001).At the same time,the expression of TLR4 mRNA and protein was markedly induced in the liver after chronic ethanol consumption(1.45±0.07 vs 0.44±0.04,P<0.0001;1.83±0.13 vs 0.56±0.08,P<0.0001).Compared with model group,betaine feeding resulted in significant decreases of ALT(64.93 ±6.06 U/L vs 159.41±7.74 U/L,P<0.0001),AST(188.73±1.11 U/L vs 248.25±1.40 U/L,P<0.0001),endotoxin(61.80±12.56 ng/L vs 135.37±30.17 ng/L,P<0.0001),TNF-α(9.79±1.32 pg/mL vs 20.81± 8.58 pg/mL,P=0.0003),IFN-γ(18.02±5.96 pg/mL vs 30.18±7.60 pg/mL,P=0.0008)and IL-18(18.23±7.01 pg/mL vs 40.99±8.25 pg/mL,P<0.0001).Betaine also improved liver steatosis.The expression levels of TLR4 mRNA or protein in liver tissues were significantly lowered(0.62±0.04 vs 1.45±0.07,P<0.0001;and 0.65±0.06 vs 1.83±0.13,P<0.0001).There was a statistical difference of TLR4 mRNA and protein expression between high-and low-dose betaine groups(0.62±0.04 vs 0.73±0.05,P<0.0001,and 0.65±0.06 vs 0.81±0.09,P<0.0001).CONCLUSION:Betaine can prevent the alcoholinduced liver injury effectively and improve the liver function.The expression of TLR4 increases significantly in ethanol-fed rats and betaine administration can inhibit TLR4 expression.

Anti-viral role of toll like receptor 4 in hepatitis B virus infection: An in vitro study

AIM Toll like receptors plays a significant anti-viral role in different infections. The aim of this study was to look into the role of toll like receptor 4(TLR4) in hepatitis B virus(HBV) infection.METHODS Real time PCR was used to analyze the transcription of TLR4 signaling molecules, cell cycle regulators and HBV DNA viral load after triggering the Hep G2.2.15 cells with TLR4 specific ligand. Nuclear factor(NF)-κB translocation on TLR4 activation was analyzed using microscopic techniques. Protein and cell cycle analysis was done using Western Blot and FACS respectively.RESULTS The present study shows that TLR4 activation represses HBV infection. As a result of HBV suppression, there are several changes in host factors which include partial release in G1/S cell cycle arrest and changes in host epigenetic marks. Finally, it was observed that anti-viral action of TLR4 takes place through the NF-κB pathway.CONCLUSION The study shows that TLR4 activation in HBV infection brings about changes in hepatocyte microenvironment and can be used for developing a promising therapeutic target in future.

Controversial role of toll-like receptors in acute pancreatitis

Acute pancreatitis(AP)is a common clinical condition with an incidence of about 300 or more patients per million annually.About 10%-15%of patients will develop severe acute pancreatitis(SAP)and of those, 10%-30%may die due to SAP-associated complications.Despite the improvements done in the diagnosis and management of AP,the mortality rate has not significantly declined during the last decades.Toll-like receptors(TLRs)are pattern-recognition receptors that seem to play a major role in the development of numerous diseases,which make these molecules attractive as potential therapeutic targets.TLRs are involved in the development of the systemic inflammatory response syndrome,a potentially lethal complication in SAP.In the present review,we explore the current knowledge about the role of different TLRs that have been described associated with AP.The main candidate for targeting seems to be TLR4,which recognizes numerous damage-associated molecular patterns related to AP.TLR2 has also been linked with AP,but there are only limited studies that exclusively studied its role in AP.There is also data suggesting that TLR9 may play a role in AP.

Toll-like receptor 4 involvement in hepatic ischemia/reperfusion injury in mice

BACKGROUND: Toll-like receptor 4 (TLR4) is involved in innate immunity by recognizing endotoxin resulting in a burst of inflammatory cascade. We investigated the relation between activation of TLR4 and liver injury in partial hepa- tic ischemia/reperfusion (I/R) injury in mice. METHODS: TLR4-deficient mice ( C3H/Hej) and wild type mice (WT, C3H/Heouj) were used in the model of I/R injury. Partial hepatic ischemia was produced by oc- clusion of inflow to the median and left lobes for 45 mi- nutes. Blood was drawn at 1 and 3 hours after reperfusion. The blood was analyzed for aspartate aminotransferase (AST) and tumor necrosis factor alpha (TNF-α). TNF-α mRNA expression and myeloperoxidase (MPO) level in the ischemic lobes were examined by northern blot and myeloperoxidase assay respectively. RESULTS: AST levels were significantly decreased in TLR4- deficient mice compared with WT mice at both time points (WT: 1215.5 ±174. 03, 2958. 17 ± 186. 81 IU/L at 1 and 3 hours respectively vs TLR4def: 661.83±106.09, 1145.17± 132.43 IU/L at 1 and 3 hours, mean ± SD, 6 mice/group, (=-6.65 and -5.57, P <0.001). Consistent with the role of TNF-α in hepatic I/R, serum TNF-α was decreased in TLR4 deficient mice at 3 hours after reperfusion compared with WT (152.39±43.3 vs 249.12 ± 51.89, n=6, t=-3.13, P<0.05). MPO level in the ischemic lobes in TLR4 defi- cient mice at 3 hours after reperfusion was significantly low- er than that in WT mice (0.059±0.004 vs 0.173±0.025, n=6, F=33.49, P<0.001). This difference appears to be mediated at the gene level since TLR4 deficient mice had decreased TNF-α mRNA expression at 1 hour after reperfu- sion compared with WT mice (80.3±28.8 vs 189.4±24.6, t=-3.25, P<0.05). CONCLUSIONS: Compared with WT mice, TLR4-defi- cient mice appear to have a mild I/R injury. Regulation of TNF-a at mRNA level seems to have a critical effect. These suggest TLR4 be involved in the mechanism of he-patic I/R injury in mice.