MicroRNA-630 alleviates inflammatory reactions in rats with diabetic kidney disease by targeting toll-like receptor 4

BACKGROUND Diabetic kidney disease(DKD)is a major complication of diabetes mellitus.Renal tubular epithelial cell(TEC)damage,which is strongly associated with the inflammatory response and mesenchymal trans-differentiation,plays a significant role in DKD;However,the precise molecular mechanism is unknown.The recently identified microRNA-630(miR-630)has been hypothesized to be closely associated with cell migration,apoptosis,and autophagy.However,the association between miR-630 and DKD and the underlying mechanism remain unknown.AIM To investigate how miR-630 affects TEC injury and the inflammatory response in DKD rats.METHODS Streptozotocin was administered to six-week-old male rats to create a hypergly cemic diabetic model.In the second week of modeling,the rats were divided into control,DKD,negative control of lentivirus,and miR-630 overexpression groups.After 8 wk,urine and blood samples were collected for the kidney injury assays,and renal tissues were removed for further molecular assays.The target gene for miR-630 was predicted using bioinformatics,and the association between miR-630 and toll-like receptor 4(TLR4)was confirmed using in vitro investigations and double luciferase reporter gene assays.Overexpression of miR-630 in DKD rats led to changes in body weight,renal weight index,basic blood parameters and histopathological changes.RESULTS The expression level of miR-630 was reduced in the kidney tissue of rats with DKD(P<0.05).The miR-630 and TLR4 expressions in rat renal TECs(NRK-52E)were measured using quantitative reverse transcription polymerase chain reaction.The mRNA expression level of miR-630 was significantly lower in the high-glucose(HG)and HG+mimic negative control(NC)groups than in the normal glucose(NG)group(P<0.05).In contrast,the mRNA expression level of TLR4 was significantly higher in these groups(P<0.05).However,miR-630 mRNA expression increased and TLR4 mRNA expression significantly decreased in the HG+miR-630 mimic group than in the HG+mimic NC group(P<0.05).Furthermore,the levels of tumor necrosis factor-alpha(TNF-α),interleukin-1β(IL-1β),and IL-6 were significantly higher in the HG and HG+mimic NC groups than in NG group(P<0.05).However,the levels of these cytokines were significantly lower in the HG+miR-630 mimic group than in the HG+mimic NC group(P<0.05).Notably,changes in protein expression were observed.The HG and HG+mimic NC groups showed a significant decrease in E-cadherin protein expression,whereas TLR4,α-smooth muscle actin(SMA),and collagen IV protein expression increased(P<0.05).Conversely,the HG+miR-630 mimic group exhibited a significant increase in E-cadherin protein expression and a notable decrease in TLR4,α-SMA,and collagen IV protein expression than in the HG+mimic NC group(P<0.05).The miR-630 targets TLR4 gene expression.In vivo experiments demonstrated that DKD rats treated with miR-630 agomir exhibited significantly higher miR-630 mRNA expression than DKD rats injected with agomir NC.Additionally,rats treated with miR-630 agomir showed significant reductions in urinary albumin,blood glucose,TLR4,and proinflammatory markers(TNF-α,IL-1β,and IL-6)expression levels(P<0.05).Moreover,these rats exhibited fewer kidney lesions and reduced infiltration of inflammatory cells.CONCLUSION MiR-630 may inhibit the inflammatory reaction of DKD by targeting TLR4,and has a protective effect on DKD.

METTL5 promotes cell proliferation,invasion,and migration by up-regulating Toll-like receptor 8 expression in colorectal cancer

BACKGROUND N6-methyladenosine(m6A)modification represents the predominant alteration found in eukaryotic messenger RNA and plays a crucial role in the progression of various tumors.However,despite its significance,the comprehensive investigation of METTL5,a key m6A methyltransferase,in colorectal cancer(CRC)remains limited.AIM To investigate the role of METTL5 in CRC.METHODS We assessed METTL5 expression levels in clinical samples obtained from CRC patients as well as in CRC cell lines.To elucidate the downstream targets of METTL5,we performed RNA-sequencing analysis coupled with correlation analysis,leading us to identify Toll-like receptor 8(TLR8)as a potential downstream target.In vitro functional assessments of METTL5 and TLR8 were conducted using CCK-8 assays,scratch assays,as well as assays measuring cell migration and invasion.RESULTS Our findings reveal a pronounced upregulation of METTL5 expression in both CRC cells and tissues,which correlated significantly with an unfavorable prognosis.In vitro experiments unequivocally demonstrated the oncogenic role of METTL5,as evidenced by its promotion of CRC cell proliferation,invasion,and migration.Notably,we identified TLR8 as a downstream target of METTL5,and subsequent down-regulation of TLR8 led to a significant inhibition of CRC cell proliferation,invasion,and tumor growth.CONCLUSION The heightened expression of METTL5 in CRC is strongly associated with clinicopathological features and a poor prognosis,thereby underscoring its potential utility as a critical marker for facilitating early diagnosis and prognostication in CRC.

Toll-like receptors 2 polymorphism is associated with psoriasis: A case-control study in the northern Chinese population

Background:Psoriasis is a disease caused by genetics and immune system dysfunction,affecting the skin and joints.Toll-like receptors(TLRs)play an important role in triggering the innate immune response and controlling adaptive immunity.The role of TLR2 in the progression of psoriasis is not well understood.Methods:A case-control study was conducted on a northern Chinese Han population,consisting of psoriasis patients and healthy control subjects.Genotyping was performed using the tetra-primer amplification refractory mutation system-polymerase chain reaction(ARMS-PCR),and allele and genotype frequencies of four SNPs in TLR2 were analyzed in 270 psoriasis patients and 246 healthy controls.Results:Four TLR2 SNPs(rs11938228,rs4696480,rs3804099,rs5743699)were genotyped and found to be in linkage disequilibrium.The genotype distributions of rs11938228 and rs4696480 in two groups were in Hardy-Weinberg equilibrium and statistically significant except for the overdominance model.The haplotypes ATTC and ATCC were found to be protective against psoriasis.Conclusion:Our study found a correlation between TLR2 genetic variations and the likelihood of psoriasis in northern China.

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.

Argon preconditioning protects neuronal cells with a Toll-like receptor-mediated effect

The noble gas argon has the potential to protect neuronal cells from cell death.So far,this effect has been studied in treatment after acute damage.Preconditioning using argon has not yet been investigated.In this study,human neuroblastoma SH-SY5Y cells were treated with different concentrations of argon(25%,50%,and 74%;21%O_(2),5%CO_(2),balance nitrogen)at different time intervals before inflicting damage with rotenone(20μM,4 hours).Apoptosis was determined by flow cytometry after annexin V and propidium iodide staining.Surface expressions of Toll-like receptors 2 and 4 were also examined.Cells were also processed for analysis by western blot and qPCR to determine the expression of apoptotic and inflammatory proteins,such as extracellular-signal regulated kinase(ERK1/2),nuclear transcription factor-κB(NF-κB),protein kinase B(Akt),caspase-3,Bax,Bcl-2,interleukin-8,and heat shock proteins.Immunohistochemical staining was performed for TLR2 and 4 and interleukin-8.Cells were also pretreated with OxPAPC,an antagonist of TLR2 and 4 to elucidate the molecular mechanism.Results showed that argon preconditioning before rotenone application caused a dose-dependent but not a time-dependent reduction in the number of apoptotic cells.Preconditioning with 74%argon for 2 hours was used for further experiments showing the most promising results.Argon decreased the surface expression of TLR2 and 4,whereas OxPAPC treatment partially abolished the protective effect of argon.Argon increased phosphorylation of ERK1/2 but decreased NF-κB and Akt.Preconditioning inhibited mitochondrial apoptosis and the heat shock response.Argon also suppressed the expression of the pro-inflammatory cytokine interleukin-8.Immunohistochemistry confirmed the alteration of TLRs and interleukin-8.OxPAPC reversed the argon effect on ERK1/2,Bax,Bcl-2,caspase-3,and interleukin-8 expression,but not on NF-κB and the heat shock proteins.Taken together,argon preconditioning protects against apoptosis of neuronal cells and mediates its action via Toll-like receptors.Argon may represent a promising therapeutic alternative in various clinical settings,such as the treatment of stroke.

Correlation between Toll-like Receptor Gene Polymorphisms and Idiopathic Nephrotic Syndrome in Chinese Children

Objective Idiopathic nephrotic syndrome(INS)is the most common glomerular disease in children.Toll-like receptors(TLRs)have been reported to be associated with response to steroid treatment in children with INS.Nevertheless,the correlation between TLR genes and the progression of INS has not yet been clarified.The present study aimed to investigate the association of single-nucleotide polymorphisms(SNPs)in TLR2,TLR4,and TLR9 with susceptibility to INS as well as the clinical phenotyping of steroid responsiveness in Chinese children with INS.Methods A total of 183 pediatric inpatients with INS were included and given standard steroid therapy.Based on their clinical response to steroids,the patients were classified into three groups:steroid-sensitive nephrotic syndrome(SSNS),steroid-dependent nephrotic syndrome(SDNS),and steroid-resistant nephrotic syndrome(SRNS).A total of 100 healthy children were employed as controls.The blood genome DNA was extracted from each participant.Six SNPs(rs11536889,rs1927914,rs7869402,rs11536891,rs352140,and rs3804099)in TLR2,TLR4,and TLR9 were selected and detected by multiplex polymerase chain reaction with next-generation sequencing to assess TLR gene polymorphisms.Results Among the 183 patients with INS,89(48.6%)had SSNS,73(39.9%)had SDNS,and 21(11.5%)had SRNS.No significant difference was found in the genotype distribution between healthy children and patients with INS.However,the genotype and allele frequencies of TLR4 rs7869402 were significantly different between SRNS and SSNS.Compared with patients with the C allele and CC genotype,patients with the T allele and CT genotype had an increased risk of SRNS.Conclusion TLR4 rs7869402 affected the steroid response in Chinese children with INS.It might be a predictor for the early detection of SRNS in this population.

Relationship of Toll-Like Receptors 2 and 4 Gene Polymorphisms with Essential Hypertension in Chinese Han Population

Objective: There are numerous studies suggesting that genetic polymor-phisms of inflammation factors Toll-like receptors 2 and 4 (TLR2, TLR4) might play a role in the pathophysiological process of hypertension. In this study, we evaluated the association in a sample of members of the Chinese Han population. Method: We selected four single nucleotide polymor-phisms (SNP) of TLR2 (rs3804099, rs3804100, rs7656411) and TLR4 (rs1927906) genes, and measured the distributions of genotypic and allelic frequencies in 1063 participants, including 391 essential hypertension pa-tients and 672 controls. Result: No significant differences in the genotypic and allelic frequencies of the four SNPs were detected between cases and controls. However, three haplotypes, CCG, TTG and TTT of TLR2, were significantly associated with a decrease in the risk of essential hyperten-sion (OR: 0.512, 95% CI: 0.397 - 0.660, P P = 0.0038;OR: 0.797, 95% CI: 0.667 - 0.952, P = 0.0122, respectively). Inversely, the risk of essential hypertension increased sig-nificantly in patients with the CTG, TCG or TCT haplotypes (OR: 2.924, 95% CI: 2.157 - 3.963, P P P Conclusion: Our study suggested that haplotypes (CCG, TTG, TTT, CTG, TCG and TCT) of TLR2 might have profound effects on the development of essential hypertension in the Chinese Han population.

Cortico-striatal gamma oscillations are modulated by dopamine D3 receptors in dyskinetic rats

Long-term levodopa administration can lead to the development of levodopa-induced dyskinesia.Gamma oscillations are a widely recognized hallmark of abnormal neural electrical activity in levodopa-induced dyskinesia.Currently,studies have reported increased oscillation power in cases of levodopa-induced dyskinesia.However,little is known about how the other electrophysiological parameters of gamma oscillations are altered in levodopa-induced dyskinesia.Furthermore,the role of the dopamine D3 receptor,which is implicated in levodopa-induced dyskinesia,in movement disorder-related changes in neural oscillations is unclear.We found that the cortico-striatal functional connectivity of beta oscillations was enhanced in a model of Parkinson’s disease.Furthermore,levodopa application enhanced cortical gamma oscillations in cortico-striatal projections and cortical gamma aperiodic components,as well as bidirectional primary motor cortex(M1)↔dorsolateral striatum gamma flow.Administration of PD128907(a selective dopamine D3 receptor agonist)induced dyskinesia and excessive gamma oscillations with a bidirectional M1↔dorsolateral striatum flow.However,administration of PG01037(a selective dopamine D3 receptor antagonist)attenuated dyskinesia,suppressed gamma oscillations and cortical gamma aperiodic components,and decreased gamma causality in the M1→dorsolateral striatum direction.These findings suggest that the dopamine D3 receptor plays a role in dyskinesia-related oscillatory activity,and that it has potential as a therapeutic target for levodopa-induced dyskinesia.

Fecal microbiota transplantation alleviates experimental colitis through the Toll-like receptor 4 signaling pathway

BACKGROUND Fecal microbiota transplantation(FMT)has shown promising therapeutic effects on mice with experimental colitis and patients with ulcerative colitis(UC).FMT modulates the Toll-like receptor 4(TLR4)signaling pathway to treat some other diseases.However,it remains unknown whether this modulation is also involved in the treatment of UC.AIM To clarify the necessity of TLR4 signaling pathway in FMT on dextran sodium sulphate(DSS)-induced mice and explain the mechanism of FMT on UC,through association analysis of gut microbiota with colon transcriptome in mice.METHODS A mouse colitis model was constructed with wild-type(WT)and TLR4-knockout(KO)mice.Fecal microbiota was transplanted by gavage.Colon inflammation severity was measured by disease activity index(DAI)scoring and hematoxylin and eosin staining.Gut microbiota structure was analyzed through 16S ribosomal RNA sequencing.Gene expression in the mouse colon was obtained by transcriptome sequencing.RESULTS The KO(DSS+Water)and KO(DSS+FMT)groups displayed indistinguishable body weight loss,colon length,DAI score,and histology score,which showed that FMT could not inhibit the disease in KO mice.In mice treated with FMT,the relative abundance of Akkermansia decreased,and Lactobacillus became dominant.In particular,compared with those in WT mice,the scores of DAI and colon histology were clearly decreased in the KO-DSS group.Microbiota structure showed a significant difference between KO and WT mice.Akkermansia were the dominant genus in healthy KO mice.The ineffectiveness of FMT in KO mice was related to the decreased abundance of Akkermansia.Gene Ontology enrichment analysis showed that differentially expressed genes between each group were mainly involved in cytoplasmic translation and cellular response to DNA damage stimulus.The top nine genes correlating with Akkermansia included Aqp4,Clca4a,Dpm3,Fau,Mcrip1,Meis3,Nupr1 L,Pank3,and Rps13(|R|>0.9,P<0.01).CONCLUSION FMT may ameliorate DSS-induced colitis by regulating the TLR4 signaling pathway.TLR4 modulates the composition of gut microbiota and the expression of related genes to ameliorate colitis and maintain the stability of the intestinal environment.Akkermansia bear great therapeutic potential for colitis.

Role of gut microbiota and Toll-like receptors in nonalcoholic fatty liver disease

Emerging data have shown a close association between compositional changes in gut microbiota and the development of nonalcoholic fatty liver disease(NAFLD).The change in gut microbiota may alter nutritional absorption and storage.In addition,gut microbiota are a source of Toll-like receptor(TLR)ligands,and their compositional change can also increase the amount of TLR ligands delivered to the liver.TLR ligands can stimulate liver cells to produce proinflammatory cytokines.Therefore,the gut-liver axis has attracted much interest,particularly regarding the pathogenesis of NAFLD.The abundance of the major gut microbiota,including Firmicutes and Bacteroidetes,has been considered a potential underlying mechanism of obesity and NAFLD,but the role of these microbiota in NAFLD remains unknown.Several reports have demonstrated that certain gut microbiota are associated with the development of obesity and NAFLD.For instance,a decrease in Akkermansia muciniphila causes a thinner intestinal mucus layer and promotes gut permeability,which allows the leakage of bacterial components.Interventions to increase Akkermansia muciniphila improve the metabolic parameters in obesity and NAFLD.In children,the levels of Escherichia were significantly increased in nonalcoholic steatohepatitis(NASH)compared with those in obese control.Escherichia can produce ethanol,which promotes gut permeability.Thus,normalization of gut microbiota using probiotics or prebiotics is a promising treatment option for NAFLD.In addition,TLR signaling in the liver is activated,and its downstream molecules,such as proinflammatory cytokines,are increased in NAFLD.To data,TLR2,TLR4,TLR5,and TLR9 have been shown to be associated with the pathogenesis of NAFLD.Therefore,gut microbiota and TLRs are targets for NAFLD treatment.

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.

Toll-like receptors in pathophysiology of liver diseases

Toll-like receptors(TLRs) are pattern recognition receptors that participate in host defense by recognizing pathogen-associated molecular patterns alongside inflammatory processes by recognizing damage associated molecular patterns. Given constant exposure to pathogens from gut, strict control of TLR-associated signaling pathways is essential in the liver, which otherwise may lead to inappropriate production of pro-inflammatory cytokines and interferons and may generate a predisposition to several autoimmune and chronic inflammatory diseases. The liver is considered to be a site of tolerance induction rather than immunity induction, with specificity in hepatic cell functions and distribution of TLR. Recent data emphasize significant contribution of TLR signaling in chronic liver diseases via complex immune responses mediating hepatocyte(i.e., hepatocellular injury and regeneration) or hepatic stellate cell(i.e., fibrosis and cirrhosis) inflammatory or immune pathologies. Herein, we review the available data on TLR signaling, hepatic expression of TLRs and associated ligands, as well as the contribution of TLRs to the pathophysiology of hepatic diseases.

Divergent expression of bacterial wall sensing toll-like receptors 2 and 4 in colorectal cancer

To characterize the expression of toll-like receptors (TLR) 2 and 4 in colorectal cancer (CRC) and in normal colorectal mucosa. METHODSWe analysed tissue samples from a prospective series of 118 unselected surgically treated patients with CRC. Sections from formalin fixed, paraffin embedded specimens were analysed for TLR2 and TLR4 expression by immunohistochemistry. Two independent assessors evaluated separately expression at the normal mucosa, at the invasive front and the bulk of the carcinoma, and in the lymph node metastases when present. Expression levels in different locations were compared and their associations with clinicopathological features including TNM-stage and the grade of the tumour and 5-year follow-up observations were analysed. RESULTSNormal colorectal epithelium showed a gradient of expression of both TLR2 and TLR4 with low levels in the crypt bases and high levels in the surface. In CRC, expression of both TLRs was present in all cases and in the major proportion of tumour cells. Compared to normal epithelium, TLR4 expression was significantly weaker but TLR2 expression stronger in carcinoma cells. Weak TLR4 expression in the invasive front was associated with distant metastases and worse cancer-specific survival at 5 years. In tumours of the proximal colon the cancer-specific survival at 5 years was 36.9% better with strong TLR4 expression as compared with those with weak expression (P = 0.044). In contrast, TLR2 expression levels were not associated with prognosis. Tumour cells in the lymph node metastases showed higher TLR4 expression and lower TLR2 expression than cells in primary tumours. CONCLUSIONTumour cells in CRC show downregulation of TLR4 and upregulation of TLR2. Low expression of TLR4 in the invasive front predicts poor prognosis and metastatic disease.

MyD88-independent activation of a novel actin-Cdc42/Rac pathway is required for Toll-like receptor-stimulated phagocytosis

Phagocytosis and subsequent degradation of pathogens by macrophages play a pivotal role in host innate immune responses to microbial infection. Recent studies have shown that Toll-like receptors （TLRs） play an important role in promoting the clearance of bacteria by up-regulating the phagocytic activity of macrophages. However, information regarding the signaling mechanism of TLR-mediated phagocytosis is still limited. Here, we provide evidence that the stimulation of TLR4 with LPS leads to activation of multiple signaling pathways including MAP kinases, phosphatidylinositide 3-kinase （PI3K）, and small GTPases in the murine macrophage-like cell line RAW264.7. Specific inhibition of Cdc42/Rac or p38 MAP kinase, but not PI3K, reduced TLR4-induced phagocytosis of bacteria. Moreover, we have found that either inhibition of actin polymerization by cytochalasin D or the knockdown of actin by RNAi markedly reduced the activation of Cdc42 and Rac by LPS. TLR4-induced activation of Cdc42 and Rac appears to be independent of MyD88. Taken together, our results described a novel actin-Cdc42/Rac pathway through which TLRs can specifically provoke phagocytosis.

N-acetylcysteine inhibits activation of toll-like receptor 2 and 4 gene expression in the liver and lung after partial hepatic ischemia-reperfusion injury in mice

BACKGROUND: Toll-like receptor 2 and 4 (TLR2/4) may play important roles in ischemia-reperfusion (I/R) injury, and N-acetylcysteine (NAC) can prevent the generation of reactive oxygen species (ROS) induced by I/R injury. This study aimed to investigate the changes in TLR2/4 gene expression in the liver and lung after I/R injury with or without NAC pretreatment. METHODS: BALB/c mice were used in a model of partial hepatic I/R injury and randomly assigned to a sham-operated control group (SH), a hepatic ischemia/reperfusion group (I/R) or a NAC pretreated, hepatic I/R group (I/R-NAC). The levels of TNF-alpha in the portal vein and plasma alanine aminotransferase (ALT) were measured at 1 and 3 hours after reperfusion. The lung wet-to-dry ratio was measured, and the expression of TLR2/4 mRNA and protein in the liver and lung were assessed with RT-PCR and Western blotting at the same time points. RESULTS: Compared with the I/R group, the expression of TLR2/4 mRNA and protein in the liver and lung in the I/R-NAC group was decreased at the same time point (P<0.05). The levels of portal vein TNF-a and plasma ALT increased continuously in the l/R group at I and 3 hours of reperfusion compared with the SH group; however, they declined significantly in the group pretreated with NAC (P<0.05). The extent of lung edema was relieved in the I/R-NAC group compared with the I/R group (P<0.05). CONCLUSIONS: TLR2/4 was activated in the liver and lung in the process of partial hepatic I/R injury. NAC inhibited the activation of TLR2/4 and the induction of TNF-alpha resulting from I/R injury via modulating the redox state, thus it may mitigate liver and lung injury following partial hepatic I/R in mice.

Control of hepatitis B virus replication by interferons and Toll-like receptor signaling pathways

Hepatitis B virus (HBV) infection is one of the major causes of liver diseases, affecting more than 350 million people worldwide. The interferon (IFN)-mediated innate immune responses could restrict HBV replication at the different steps of viral life cycle. Indeed, IFN-&#x003b1; has been successfully used for treatment of patients with chronic hepatitis B. However, the role of the innate immune response in HBV replication and the mechanism of the anti-HBV effect of IFN-&#x003b1; are not completely explored. In this review, we summarized the currently available knowledge about the IFN-mediated anti-HBV effect in the HBV life cycle and the possible effectors downstream the IFN signaling pathway. The antiviral effect of Toll-like receptors (TLRs) in HBV replication is briefly discussed. The strategies exploited by HBV to evade the IFN- and TLR-mediated antiviral actions are summarized.

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.

Epithelial toll-like receptor 9 signaling in colorectal inflammation and cancer: Clinico-pathogenic aspects

Toll-like receptors (TLRs) recognize specific motifs which are frequently present in bacteria, fungi, prokaryotes and viruses. Amongst TLRs, TLR9 can be activated by such bacterial or viral DNA fragments, immunoglobulin-DNA complexes or synthetic oligonucleotides, which all contain unmethylated cytosineguanine nucleotide sequences (CpGs). Emerging data indicate that TLR9 signaling has a role in, and may influence, colorectal carcinogenesis and colonic inflammation. CpGs are classified into three groups according to their influence on both the antigen-specific humoraland cellular immunity, and the production of type 1 interferons and proinflammatory cytokines. TLR9 activation via CpGs may serve as a new therapeutic target for several cancerous and various inflammatory conditions. Due to its probable anti-cancer effects, the application possibilities of TLR9-signaling modulation may be extremely diverse even in colorectal tumors. In this review we aimed to summarize the current knowledge about TLR-signaling in the pathogenesis and therapy of inflammatory bowel diseases and colorectal cancer. Due to the species-specific differences in TLR9 expression, however, one must be careful in translating the animal model data into the human system, because of the differences between CpG-oligodeoxynucleotide-responsive cells. TLR9 agonist DNA-based immunomodulatory sequences could also represent a promising therapeutic alternative in systemic inflammatory conditions and chronic colonic inflammations as their side effects are not significant.

Short-Term Inhalation of Nitric Oxide Inhibits Activations of Toll-Like Receptor 2 and 4 in the Lung after Ischemia-Reperfusion Injury in Mice

In order to investigate the effects of different terms of inhaled nitric oxide （NO） preconditioning with low concentration on the activations of Toll-like receptor 2 and 4 （TLR2/4） in the lung ischemia-reperfusion （IR） injury in mice, we divided the male C57BL mice into five groups： sham （S） group, IR group, NO 1-min preconditioning group （15 ppm NO inhalation for 1 min before ischemia, NO 1-min）, NO 10-min preconditioning group （15 ppm NO inhalation for 10 min before ischemia, NO 10-min）, NO 60-min preconditioning group （15 ppm NO inhalation for 60 min before ischemia, NO 60-min）. The changes of partial pressure of oxygen in artery （PaO2）, left lung wet-to-dry weight ratio （W/D）, and myeloperoxidase （MPO） in the injured lung were measured in every group at 6th h of reperfusion after 60 min of left lung ischemia. The changes of TLR2/4 activations and plasma TNF-a were measured in this procedure in additional mice. As compared with IR group, PaO2 increased, MPO and W/D decreased evidently after reperfusion in NO 10-min group. The changes in NO 60-min group were similar to those in NO 10-rain group. There was no difference between NO 1-min and IR group. In NO inhalation group, the expressions levels of TLR2/4 mRNA and proteins were diminished, TNF-~t concentrations were decreased, and the lung injuries were ameliorated effectively. We concluded that short term inhalation of NO protected lung IR injury. But the protective effect of NO was not increased with extension of inhaled NO. Inhaled NO could inhibit the activations of TLR2/4 in the lung after IR injury. TLR signal pathway might contribute to the effect of protection with NO in this model.

Faecal and mucosal microbiota in patients with functional gastrointestinal disorders: Correlation with toll-like receptor 2/toll-like receptor 4 expression

AIM To investigate the intestinal luminal microbiota(LM)and mucosa-associated microbiota(MAM)in Chinese patients with functional gastrointestinal disorders(FGIDs)and examine the association between these communities and the expression of toll-like receptor(TLR)2 and TLR4. METHODS Thirty-two Chinese subjects who suffered from symptoms of FGIDs,as confirmed by gastroenterologists,were enrolled in this study.Fresh faecal samples and descending colonic mucosal biopsies were collected from the subjects before(faecal)and during(mucosal) flexible colonoscopy.For analysis of the samples,we performed high-throughput sequencing of the V3-V4region of the 16S rR NA gene and reverse transcription(RT)-PCR to detect the expression of colonic TLR2 and TLR4.Differences in the stool and mucosal microbiota were examined and a correlation network analysis was performed. RESULTS The microbiota of faecal samples was significantly more diverse and richer than that of the mucosal samples,and the LM and MAM populations differed significantly.TLR2 expression showed a significant positive correlation with TLR4 expression.In the MAM samples,the genera Faecalibacterium and Ruminococcus,which belong to the family Ruminococcaceae,were inversely correlated with TLR4 expression(r=-0.45817,P=0.0083 and r=-0.5306,P=0.0018,respectively).Granulicatella,which belongs to Carnobacteriaceae,and Streptococcus,which belongs to Streptococcaceae,were inversely correlated with TLR2 expression(r=-0.5573,P=0.0010 and r=-0.5435,P=0.0013,respectively).In the LM samples,examination at phylum,class,or order level revealed no correlation with TLR4 expression.Faecalibacterium,which belongs to Ruminococcaceae,and Streptococcus,which belongs to Streptococcaceae,were inversely correlated with TLR2 expression(r=-0.5743,P=0.0058 and r=-0.3905,P=0.0271,respectively). CONCLUSION Microbial compositions of LM and MAM in Chinese patients with FGIDs are different.Expression of TLRs may be affected by the type of bacteria that are present in the gut.