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.

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.

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.

Association between polymorphisms in the Toll-like receptor 4,CD14,and CARD15/NOD2and inflammatory bowel disease in the Greek population

AIM: Crohn's disease(CD)and ulcerative colitis(UC)are multifactorial diseases with a significant genetic background.Apart from CARD15/NOD2 gene, evidence is accumulating that molecules related to the innate immune response such as CD14 or Toll-like receptor 4 (TLR4), are involved in their pathogenesis. In further exploring the genetic background of these diseases, we investigated the variations in the CARD15/NOD2 gene (Arg702Trp,Gly908Arg and Leu1007fsinsC), and polymorphisms in the TLR4 gene (Asp299Gly and Thr399Ile) as well as in the promoter of the CD14 gene (T/C at position -159) in Greek patients with CD and UC.METHODS: DNA was obtained from 120 patients with CD,85 with UC and 100 healthy individuals. Genotyping was performed by allele specific PCR or by PCR-RFLP analysis.RESULTS: The 299Gly allele frequency of the TLR4 gene and the T allele and TT genotype frequendes of the CD14 promoter were significantly higher in CD patients only compared to healthy individuals (P = 0.026＜0.05; P = 0.0048＜0.01 and P= 0.047＜0.05 respectively). Concerning the NOD2/CARD15mutations the overall presence in CD patients was significantly higher than that in UC patients or in controls.Additionally, 51.67% of the CD patients were carriers of a TLR4 and/or CD14 polymorphic allele and at least one variant of the NOD2/CARD15, compared to 27% of the UC patients. It should be pointed out that both frequencies significantly increased as compared with the 10% frequency of multiple carriers found in healthy controls. A possible interaction of the NOD2/CARD15 with TLR4 and especially CD14, increased the risk of developing inflammatory bowel disease (IBD).CONCLUSION: Our results indicate that co-existence of a mutation in either the TLR4 or CD14 gene, and in NOD2/CARD15is associated with an increased susceptibility to developing CD compared to UC, and to developing either CD or UC compared to healthy individuals.

Clinical significance of NOD2/CARD15 and Toll-like receptor 4 gene single nucleotide polymorphisms in inflammatory bowel disease

AIM： To evaluate the role of genetic factors in the pathogenesis of Crohn＇s disease （CD） and ulcerative colitis （UC）, we investigated the single nucleotide polymorphisms （SNPs） of NOD2/CARD15 （R702W, Gg08R and L1007finsC）, and Toll-like receptor 4 （TLR4） genes （D299G and T399I） in a selected inflammatory bowel disease （IBD） population coming from Southern Italy. METHODS： Allele and genotype frequencies of NOD2/ CARD15 （R702W, Gg08R and L1007finsC） and TLR4 （D299G and T399I） SNPs were examined in 133 CD patients, in 45 UC patients, and in 103 healthy controls. A genotype-phenotype correlation was performed. RESULTS： NOD2/CARD15 R702W mutation was significantly more frequent in CD （9.8%） than in controls （2.4%, P = 0.001） and in UC （2.3%, P = 0.03）. No significant difference was found between UC patients and control group （P 〉 0.05）. In CD and UC patients, no significant association with G908R variant was found. L1007finsC SNP showed an association with CD （9.8%） compared with controls （2.9%, P = 0.002） and UC patients （2.3%, P = 0.01）. Moreover, in CD patients, G908R and L1007finsC mutations were significantly associated with different phenotypes compared to CD wild-type patients. No association of IBD with the TLR4 SNPs was found in either cohort （allele frequencies： D299G-controls 3.9%, CD 3.7%, UC 3.4%, P 〉 0.05; T399I-controls 2.9%, CD 3.0%, UC 3.4%, P 〉 0.05）. CONCLUSION： These findings confirm that, in our IBD patients selected from Southern Italy, the NOD2/ CARD15, but not TLR4 SNPs, are associated with increased risk of CD.

人Toll-like receptor 2胞外段的克隆和表达

目的 克隆、表达人Toll-like receptor2(TLR2)胞外段(A26-T588)基因,获得人TLR2胞外段蛋白。方法 RT-PCR扩增TLR2胞外段基因,以pcDNA3.1+质粒为载体在HEK293细胞中表达TLR2胞外段蛋白,同时以pcDNA3.1+/TLR2(A26-T588)重组质粒免疫昆明鼠,制备抗TLR2胞外段蛋白多抗。结果 PCR扩增及重组质粒测序结果表明成功地构建了pcDNA3.1+/TLR2(A26-T588)真核表达质粒,SDS-PAGE分析纯化产物在M_r为68000处出现明显蛋白条带。重组质粒DNA免疫小鼠3次后,血清抗体滴度可达1∶250。TLR2胞外段蛋白可与LPS结合,并在一定的质量浓度范围内呈剂量依赖性。结论 构建的pcDNA3.1+/TLR2(A26-T588)真核表达质粒可在哺乳动物细胞中表达TLR2胞外段蛋白,并与重组质粒DNA免疫小鼠抗血清及TLR2单克隆抗体TL2.1特异性反应,由此证明其表达正确。

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。

Toll-like Receptor9在大鼠胰腺表达及与大鼠急性胰腺炎相关性的研究

目的 (1)建立急性胰腺炎大鼠模型,定性检测Toll-like Receptor 9(TLR 9)在大鼠胰腺的表达、分布情况;(2)定量测定TLR 9在大鼠急性胰腺炎不同时间点的表达变化情况;(3)结合TLR 9在大鼠胰腺的组织分布、表达情况及在雨蛙素诱导性胰腺炎(cerulein-induced pancreatitis,CIP)早期24 h的表达改变,探讨TLR9与CIP发生发展的相关性.方法(1)采用Wistar大鼠,并随机分配进入实验组或对照组;通过皮下注射雨蛙素建立急性胰腺炎模型;(2)采用免疫组化方法检测TLR 9在正常大鼠胰腺及CIP时大鼠胰腺的表达TLR 9在大鼠胰腺的组织分布情况;(3)提取总RNA,采用实时荧光定量逆转录-多聚酶链反应(Quantitative-Real-Time;QRT-PCR)法测定TLR9基因的表达.(4)分析TLR9的分布特征及可能的意义(5)统计分析TLR 9 mRNA的表达情况与CIP发生、发展的关系.结果 (1)TLR 9主要分布于胰管上皮、血管内皮和胰岛;(2)外分泌腺泡细胞没有明显的表达;(3)QRT-PCR结果显示TLR9 mRNA在正常大鼠胰腺组织呈现低水平表达;(4)CIP早期TLR9 mRNA表达出现快速上调并在1 h时达到最高值;TLR 9 mRNA表达在CIP前4 h内维持于高水平;其后下降缓慢,至到CIP的第24小时也未降至正常,保持相对较高的表达水平.结论 (1)TLR 9在大鼠胰腺有表达,且表达具有一定的组织特异性;(2)TLR9在CIP胰腺组织中的表达明显升高,提示TLR 9在胰腺炎早期炎症反应的发生、发展中具有重要作用,与之存在相关性.

Toll-like receptor 2及其信号传导通路在阿片类物质诱导细胞凋亡中的作用

目的:成瘾物质(Addictive drugs)导致的中毒性脑病的中枢神经系统损害以神经元凋亡为突出表现,具体机制仍有待进一步的研究探讨。方法:Toll-like receptor 2(TLR2)不仅是激活机体自身免疫防御和炎症反应的重要受体,而且广泛参与多种细胞功能,包括细胞凋亡。我们使用体外培养的HEK293和高表达TLR2的HEK2932种细胞,以及体外培养小鼠皮层原代神经元细胞,研究经过吗啡处理后细胞存活率和凋亡的变化,以探讨TLR2信号通路在吗啡诱导的细胞凋亡中的作用。结果:TLR2高表达导致吗啡诱导的细胞存活率下降和细胞凋亡的显著增加。使用MyD88抑制体竞争性抑制MyD88并阻断TLR2信号通路后,吗啡诱导的TLR2高表达细胞的凋亡也被明显抑制。长期的吗啡处理导致正常神经元的TLR2在信使RNA(mRNA)水平和蛋白水平表达明显增高,而且在TLR2功能缺失的原代神经元细胞中,吗啡诱导的caspase-3活性增高被阻断,吗啡诱导的神经元凋亡也被明显抑制。结论:TLR2信号通路参与吗啡诱导的神经元凋亡。

IL-15的免疫调节功能及其相关疾病研究进展

IL-15作为免疫调控的关键分子,主要由髓系细胞分泌产生。IL-15在T细胞、自然杀伤细胞和记忆CD8+T细胞稳态和功能方面发挥重要作用,因其具有广泛表达、严格分泌的特性在多种免疫相关疾病中体现出良好的治疗潜能。IL-15与IL-15受体特异性结合后,激活下游JAK/STAT、Ras/Raf/MAPK及PI3K/AKT等多种信号通路,通过诱导细胞增殖、分化和凋亡,从而发挥抗肿瘤、抗感染等生物学效应。本文主要综述了IL-15在肿瘤、自身免疫疾病和神经精神疾病等中的作用与相关机制,并总结了以IL-15为潜在治疗靶点的小分子激动剂和抑制剂,以期为深入探究IL-15在免疫系统疾病中的发病机制和药物研究提供科学依据。

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.

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.

The role of Toll-like receptors in non-infectious lung injury

The role of Toll-like receptors （TLRs） in pathogen recognition has been expeditiously advanced in recent years. However, investigations into the function of TLRs in non-infectious tissue injury have just begun. Previously, we and others have demonstrated that fragmented hyaluronan （HA） accumulates during tissue injury. CD44 is required to clear HA during tissue injury, and impaired clearance of HA results in unremitting inflammation. Additionally, fragmented HA stimulates the expression of inflammatory genes by inflammatory cells at the injury site. Recently, we identified that HA fragments require both TLR2 and TLR4 to stimulate mouse macrophages to produce inflammatory chemokines and cytokines. In a non-infectious lung injury model, mice deficient in both TLR2 and TLR4 show an impaired transepithelial migration of inflammatory cells, increased tissue injury, elevated lung epithelial cell apoptosis, and decreased survival. Lung epithelial cell overexpression of high molecular mass HA protected mice against acute lung injury and apoptosis, in part through TLR-dependent basal activation of NF-κB. The exaggerated injury in TLR2 and TLR4 deficient mice appears to be due to impaired HA-TLR interactions on epithelial cells. These studies identify that host matrix component HA and TLR interactions provide signals that initiate inflammatory responses, maintain epithelial cell integrity, and promote recovery from acute lung injury.

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.