Toll-like receptor 3 (TLR3) regulation mechanisms and roles in antiviral innate immune responses / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Toll-like receptor 3 (TLR3) is a member of the TLR family, mediating the transcriptional induction of type I interferons (IFNs), proinflammatory cytokines, and chemokines, thereby collectively establishing an antiviral host response. Studies have shown that unlike other TLR family members, TLR3 is the only RNA sensor that is utterly dependent on the Toll-interleukin-1 receptor (TIR)‍-domain-containing adaptor-inducing IFN-‍β (TRIF). However, the details of how the TLR3-TRIF signaling pathway works in an antiviral response and how it is regulated are unclear. In this review, we focus on recent advances in understanding the antiviral mechanism of the TRIF pathway and describe the essential characteristics of TLR3 and its antiviral effects. Advancing our understanding of TLR3 may contribute to disease diagnosis and could foster the development of novel treatments for viral diseases.

Microcefalia por Zika un problema latente: Reporte de Caso y Aspectos Moleculares / Zika microcephaly a latent problem: Case Report and Molecular Aspects

Se presenta el caso de un paciente de 20 días de nacido, procedente de Cartagena (Bolívar), hospitalizado por presentar fiebre de 6 días de evolución asociado a sintomatología respiratoria con evaluación neurológica normal. La ecografía obstétrica evidenció una microcefalia con un percentil de perímetro cefálico <2, con hipoplasia del cuerpo calloso y tomografía axial computarizada de cráneo que reportó diámetros cefálicos disminuidos, finas calcificaciones residuales en región frontal-parietal y cambios atróficos cerebrales subcorticales. Se le inició terapia antibiótica por presentar sepsis neonatal, las pruebas serológicas y la PCR para Zika resultaron positivas. Se decidió dar el alta médica al 6 día por mejoría clínica y no presentar déficit neurológico aparente. Aunque no existe un tratamiento específico, el pilar del manejo de un recién nacido con microcefalia es el seguimiento y la vigilancia futura de las posibles comorbilidades, como epilepsia, parálisis cerebral o retraso cognitivo y motor.

We present the case of a 20-day-old patient from Cartagena (Bolívar), hospitalized for presenting a 6-day fever associated with respiratory symptoms with normal neurological evaluation. The obstetric ultrasound showed a microcephaly with a percentile of cephalic perimeter <2, with hypoplasia of the corpus callosum and computed tomography of the skull that reported decreased cephalic diameters, fine residual calcifications in the frontal-parietal region and atrophic subcortical cerebral changes. Antibiotic therapy was initiated due to neonatal sepsis, the serological tests and the PCR for Zika were positive. It was decided to discharge the hospital after 6 days due to clinical improvement and for not presenting apparent neurological deficit. Although there is no specific treatment, the pillar of the management of a newborn with microcephaly is the monitoring and future surveillance of possible comorbidities, such as epilepsy, cerebral palsy or cognitive and motor retardation.

Association of TLR3 single nucleotide polymorphisms with susceptibility to HTLV-1 infection in Iranian asymptomatic blood donors

Abstract INTRODUCTION: The human T-lymphotropic virus type 1 (HTLV-1) has a single-stranded RNA genome and expresses specific proteins that have oncogenic potential. Approximately 15 to 20 million people worldwide have been infected by this virus. Changes in protein or gene expression are the effects of single nucleotide polymorphisms (SNPs) within the Toll-like receptor 3 (TLR3) gene. The function and efficacy of signal transduction also lead to modified immune responses. The present study aimed to investigate the association of SNPs within TLR3 (rs3775291 and rs3775296) with susceptibility to HTLV-1 infection in Iranian asymptomatic blood donors. METHODS: This study was performed on 100 HTLV-1-infected asymptomatic blood donors and 118 healthy blood donors. Genomic DNA from all participants was purified and then amplified using specific PCR primers. SNPs within TLR3 were evaluated using the restriction fragmentation length polymorphism technique, and the results were analyzed using SPSS software (version 22). RESULTS: The frequencies of the TLR3 (rs3775296) CC, CA, AA genotypes were 70%, 24%, and 6% in the patient group, and 50.8%, 44.9%, and 4.2% in the control group, respectively. There was a significant difference in the frequency distribution of TLR3 (rs3775296) genotypes and alleles, but not in the frequency distribution of TLR3 (rs3775291) genotypes between the patient and control groups. CONCLUSIONS: The TLR3 SNP rs3775296 was significantly associated with HTLV-1 infection and may be a protective factor against this viral infection.

Influência de TLR3 em modelo de Paracoccidioidomicose experimental / TLR3 influence in experimental PCM model

Os receptores do tipo Toll compreendem a família de receptores de reconhecimento de padrões melhor caracterizados, que podem ativar diferentes respostas imunes, dependendo de quais receptores e conjuntos de adaptadores são utilizados. Os TLRs, como TLR2, TLR4 e TLR9, e sua sinalização foram implicados no reconhecimento de P. brasiliensis e na regulação da resposta imune, no entanto, o papel do TLR3 ainda não está claro. Assim, a compreensão da função endossomal do TLR3 na PCM experimental é crucial. Utilizamos modelos in vitro e in vivo de infecção por P. brasiliensis, camundongos C57Bl/6 e TLR3-/-, para avaliar a contribuição da TLR3 no desenvolvimento da infecção. Mostramos que ausência de TLR3 leva o aumento de óxido nítrico e a capacidade fagocítica por macrófagos nas primeiras 4 horas de interação com leveduras P. brasiliensis. Mostramos ainda que os camundongos TLR3-/- desempenham papel protetor após 30 dias de infecção intratraqueal com P. brasiliensis, mostrando diminuição do aumento de CFU, perfil de resposta Th1 e Th17, bem como aumento de células citotóxicas T CD8+ produtoras de IFN-γ e IL-17. As células citotóxicas T CD8+ mostraram ser essenciais para o controle da infecção nos camundongos TLR3-/-, uma vez que a depleção dessas células levou a progressão da doença. Em estágios iniciais, 3 e 5 dias de infecção, observamos aumento do recrutamento de neutrófilos para o pulmão. Estudos recentes indicam que o TLR3 é um receptor importante para a resposta imune na micose e sua ausência favorece a infecção por fungos. Em contraste, nossos resultados mostram que, no caso do PCM, o TLR3 é prejudicial ao hospedeiro, sugerindo que a ativação do TLR3 pode ser um possível mecanismo de escape de P. brasiliensis

Toll-like receptors comprise the best-characterized pattern-recognition receptor family that can activate different immune responses, depending on which receptor and adaptor set are utilized. TLRs, such as TLR2, TLR4 and TLR9, and their signaling have been implicated in the recognition of P. brasiliensis and regulation of the immune response, however, the role of TLR3 remains unclear. Thus, understanding the endosomal function of TLR3 in experimental PCM is crucial. We used in vitro and in vivo models of infection by P. brasiliensis, C57Bl/6 and TLR3-/- mice, to assess the contribution of TLR3 on development of infection. We show that absence of TLR3 leads to increased nitric oxide and phagocytic capacity by macrophages in the first 4 hours of interaction with yeasts P. brasiliensis. We also showed that TLR3-/- mice play a protective role after 30 days of intratracheal infection with P. brasiliensis, showing a decrease in the CFU increase, Th1 and Th17 response profile, as well as an increase in cytotoxic CD8+ cells producing IFN-γ and IL-17. The cytotoxic T CD8+ cells were shown to be essential for the control of infection in TLR3-/- mice, since the depletion of these cells led to the progression of the disease. In the initial stages, 3 and 5 days of infection, we observed increased recruitment of neutrophils to the lung. Recent studies indicate that TLR3 is an important receptor for the immune response in mycosis and its absence favors fungal infection. In contrast, our results show that in the case of PCM, TLR3 is detrimental to the host, suggesting that TLR3 activation may be a possible escape mechanism of P. brasiliensis

TRIM56 Suppresses Multiple Myeloma Progression by Activating TLR3/TRIF Signaling

PURPOSE: Tripartite-motif-containing protein 56 (TRIM56) has been found to exhibit a broad antiviral activity, depending upon E3 ligase activity. Here, we attempted to evaluate the function of TRIM56 in multiple myeloma (MM) and its underlying molecular basis. MATERIALS AND METHODS: TRIM56 expression at the mRNA and protein level was measured by qRT PCR and western blot analysis. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and flow cytometry analysis was performed to investigate the effect of TRIM56 on MM cell proliferation and apoptosis. The concentrations of interferon (IFN)-β, interleukin (IL)-6, and tumor necrosis factor-α in MM cell culture supernatants were detected with respective commercial ELISA kits. Western blot was employed to determine the effect of TRIM56 on toll-like receptor 3 (TLR3)/toll-IL-1 receptor (TIR) domain-containing adaptor inducing IFN-β (TRIF) signaling pathway. RESULTS: TRIM56 expression was prominently decreased in MM cells. Poly (dA:dT)-induced TRIM56 overexpression in U266 cells suppressed proliferation, induced apoptosis, and enhanced inflammatory cytokine production, while TRIM56 knockdown improved growth, diminished apoptosis, and inhibited inflammatory cytokine secretion in RPMI8226 cells. Moreover, TRIM56 knockdown blocked TLR3 signaling pathway. Furthermore, poly (I:C), a TLR3 agonist, markedly abolished TRIM56 depletion-induced increase of proliferation, decrease of apoptosis, and reduction of inflammatory factor in MM cells. CONCLUSION: TRIM56 may act as a tumor suppressor in MM through activation of TLR3/TRIF signaling pathway, contributing to a better understanding of the molecular mechanism of TRIM56 involvement in MM pathogenesis and providing a promising therapy strategy for patients with MM.

Polarization of M1 tumor associated macrophage promoted by the activation of TLR3 signal pathway

Objective To investigate the correlation between activation of toll-like receptors 3 (TLR3) signaling pathway and tumor-associated macrophage and its effect on the tumor growth. Methods The mice Lewis lung cancer cell lines 3LL and melanoma B16H10 were used to construct the subcutaneous transplantation tumor models and then they were treated with Poly-ICLC. The curative effect was observed and then the T cell and macrophage phenotypes infiltrated in local tumor were detected by flow cytometry. After the in vitro culture of mouse bone marrow-derived macrophage, the real-time PCR and western blot were applied to detect the expression of macrophage activation markers and the activation of intracellular signaling pathways. Results The survival time of mice with brown tumor treated with Poly-ICLC significantly increased and the tumor growth was inhibited. The ratio of local tumor-infiltrated Treg decreased, while the ratio of CD8

Mechanism of total flavonoids from Mosla scabra on resistance to influenza viral pneumonia based on microRNAs / 中草药

Objective: To investigate the mechanism of flavonoids from Mosla scabra (FMS) on anti-influenza from the sight of microRNAs. Methods: Mice were divided into normal group, model (MC) group, and FMS group. Mice in MC and FMS groups were infected with influenza virus H1N1, then mice in the FMS group were treated with FMS. To observe the influence of mice in FMS group for the lung index and the levels of cytokines in serum. The difference expressing of miRNAs in lung tissue of mice in each group were detected by high-flux sequencing and quantitative real-time PCR. Human mRNA database as target was used to predict the target genes of differentially expressed miRNAs by miranda, mirbase, and targetscan analysis, while the target genes functions were considered by KEGG analyses. The related proteins of target genes were tested by Western blotting. Results: FMS could significantly decrease the lung index and cytokines of infected mice and regulate the expression levels of abnormal miRNAs tend to normal. We also found that miRNAs are relevant to JAK-STAT and TLR3 signal pathways by KEGG. Western blotting confirmed that FMS could adjust the abnormal protein level of infected mice. Conclusion: FMS obviously alleviates viral pneumonia via regulating miRNA expression in mice.

Polarization of M1 tumor associated macrophage promoted by the activation of TLR3 signal pathway

OBJECTIVE@#To investigate the correlation between activation of toll-like receptors 3 (TLR3) signaling pathway and tumor-associated macrophage and its effect on the tumor growth.@*METHODS@#The mice Lewis lung cancer cell lines 3LL and melanoma B16H10 were used to construct the subcutaneous transplantation tumor models and then they were treated with Poly-ICLC. The curative effect was observed and then the T cell and macrophage phenotypes infiltrated in local tumor were detected by flow cytometry. After the in vitro culture of mouse bone marrow-derived macrophage, the real-time PCR and western blot were applied to detect the expression of macrophage activation markers and the activation of intracellular signaling pathways.@*RESULTS@#The survival time of mice with brown tumor treated with Poly-ICLC significantly increased and the tumor growth was inhibited. The ratio of local tumor-infiltrated Treg decreased, while the ratio of CD8(+) T cell increased significantly. The macrophages surface CD206 expression was down-regulated while the expression of iNOS increased. The Poly-ICLC could promote the expression of M1 markers (IL-1β, TNF-α and iNOS) in bone marrow-derived macrophage and inhibited the expression of M2 molecules (Arg-1, YM-1 and CD206). The phosphorylation level of downstream p65, TBK1 and IRF3 increased significantly.@*CONCLUSIONS@#The Poly-ICLC can activate the TLR3 downstream signaling pathway to induce a M1 polarization of tumor associated macrophage, thereby inhibiting the tumor growth.

Toll-like receptor 3 gene polymorphisms are not associated with the risk of hepatitis B and hepatitis C virus infection

INTRODUCTION: The present study investigated the prevalence of two single-nucleotide polymorphisms (SNPs) in the Toll-like receptor 3 (TLR3) gene in patients infected with hepatitis B virus (HBV) and hepatitis C virus (HCV). METHODS: Samples collected from HCV (n = 74) and HBV (n = 35) carriers were subjected to quantitative real-time PCR (qPCR) to detect the presence of the SNPs rs5743305 and rs3775291 in TLR3 and to measure the following biomarkers: alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyl transpeptidase (GGT), and prothrombin time (PT). A healthy control group was investigated and consisted of 299 HCV- and HBV-seronegative individuals. RESULTS: No significant differences in allele, genotype and haplotype frequencies were observed between the investigated groups, and no association was observed between the polymorphisms and histopathological results. Nevertheless, genotypes TA/AA (rs5743305) and GG (rs3775291) appear to be associated with higher levels of ALT (p<0.01), AST (p<0.05) and PT (p<0.05). In addition, genotypes TT (rs5743305; p<0.05) and GG (rs3775291; p<0.05) were associated with higher GGT levels. CONCLUSIONS: This genetic analysis revealed the absence of an association between the polymorphisms investigated and susceptibility to HBV and HCV infection; however, these polymorphisms might be associated with a greater degree of biliary damage during the course of HCV infection. .

Toll-like receptor 3 (TLR3) and the development of type 1 diabetes mellitus

Type 1 diabetes mellitus (T1DM) is a chronic, progressive autoimmune disease characterized by metabolic decompensation often leading to dehydration and ketoacidosis. Viral agents seem to play an important role in triggering the autoimmune destruction that leads to the development of T1DM. Among several viral strains investigated so far, the enterovirus family has been consistently associated with the onset of T1DM in humans. One of the mediators of viral damage is the double-stranded RNA (dsRNA) generated during replication and transcription of viral RNA and DNA. The Toll-like receptor 3 (TLR3) gene codes for an endoplasmic receptor of the pattern-recognition receptors (PRRs) family that recognizes dsRNA, plays an important role in the innate immune response triggered by viral infection. Binding of dsRNA to the TLR3 triggers the release of proinflammatory cytokines, such as interferons, which exhibit potent antiviral action; thus, protecting uninfected cells and inducing apoptosis of infected ones. Therefore, the TLR3 gene is a good candidate for the development of T1DM. Within this context, the objective of the present review was to address the role of the TLR3 gene in the development of T1DM. Arch Endocrinol Metab. 2015;59(1):4-12.

The regulation of TLR3 on NF-κB signaling pathway and its significance in the pathogenesis of tumor / 实用肿瘤学杂志

NF-κBs is a member of Rel protein family of transcription factors ,which is expressed in all cells and is involved in important physiological and pathological regulatory mechanisms ,including the regulation of TLR3 on NF-κB signaling pathway ,which has been attracted widespread attention .This paper reviews the mo-lecular mechanisms of the regulation .We summarizes the role of host immune responses in tumor development , which is mediated by the related signal molecules .It reveals that some key proteins in the regulation have a great significance to the treatment of diseases ,as used as the therapeutic targets ,and is conducive to the understanding of function and diversity in tumor tissue .

Expression of p16 and TLR3 in cervical intraepithelial neoplasia and cervical invasive carci-noma and their significance / 临床与实验病理学杂志

Purpose To investigate the expression and clinical significance of the cell cycle inhibitors p16 protein and specific recogni-tion of viral replication intermediate TLR3 in the cervical intraepithelial neoplasia ( CIN) and cervical invasive carcinoma. Methods Immunohistochemical stain was used to detect the expressions of p16 and TLR3 in 19 cases of normal cervical epithelium ( NCE) , 62 cases of CIN, and 17 cases of cervical squamous cell carcinoma (SCC). Results The positive rates of p16 protein were 0, 72. 5%and 100% in NCE, CIN and SCC respectively in which the difference among those groups were statistically significant ( P<0. 01 ) . Similarly, the positive rates of TLR3 protein were 26. 3%, 87% and 100% in NCE, CIN and SCC respectively and the difference a-mong those groups was significant (P<0. 01). Furthermore, there was a significant and positive correlation between the expression of p16 and TLR3 (rs =0. 538, P<0. 01). Conclusion Increased expression is observed in CIN and SCC compared with NCE and the expression of p16 and TLR3 is associated with level of CIN. Those could provide certain experiment basis for the pathologica diagnosis of early cervical cancer.

Stimulation of TLR3 inhibits the proliferation of breast cancer cells MDA-MB-231 / 国际生物医学工程杂志

ObjectiveToll-like receptors (TLRs) play important role in the progression and tumor immunity of some types of cancer,some research have demonstrated that agonist of TLR3 can trigger apoptosis of cancers.This study was proposed to investigate if Poly(I:C),the specific agonist of TLR3,could impact proliferation or apoptosis of progressive breast cancer cells MDA-MB-231,and to investigate the primary mechanism of the function.MethodsExpression of TLR1-10 mRNA was detected by quantitative real-time reverse transcription-polymerase chain reaction.Cell Counting Kit-8 was used to determine the inhibitory effect of Poly(I:C) on proliferation of MDA-MB-231 cells.Cell apoptosis was assayed by flow cytometry with V-FITC/PI staining.Results First,the toll-like receptors 1-10 were all expressed on MDA-MB-231 cells,while the expression level of TLR8 was lower than that of others.Second,according to the CCK-8,the proliferation of MDA-MB-231 cells was inhibited,but the apoptosis was not affected on the basis of Apoptosis Kit.At last,the mRNA expression of TNF-α、IFN-β and IFN-γ were elevated approximately 20 times after Poly(I:C) stimulation for 6 hours.ConclusionMDA-MB-231 cells express all toll-like receptors on mRNA level,and TLR8 was expressed lower than others.The stimulation of TLR3 with Poly(I:C) can inhibit the proliferation of MDA-MB-231,but had no effect on apoptosis.TNF-α、IFN-β and IFN-γ maybe participate in this process.

Promoter region polymorphism & expression profile of toll like receptor-3 (TLR-3) gene in chronic hepatitis C virus (HCV) patients from India.

Background & objectives: Hepatitis C virus (HCV) induces an immune response of the host, manifested by the formation of anti-HCV antibodies mediated by adaptive and innate immunity. Toll-like receptors (TLRs) play a pivotal role in innate immunity system. This study was aimed to investigate the promoter region polymorphism and expression of TLR3 gene in patients with chronic HCV infection. Methods: Patients with chronic HCV infection (N=180) and an equal number of age-sex matched controls were included in the study. Patients positive for HCV-RNA were subjected to analysis of TLR3 polymorphism by direct sequencing of PCR products verified by comparing with the sequences reported in the National Centre for Biotechnology Information (NCBI) database (accession number: NT 022792). Expression of TLR3 gene was analyzed by semiquantitative RT-PCR using housekeeping β-actin gene as the internal control. Results: Polymorphisms at position -288G/A and -705A/G were identified. The results were significant in -705 allele (P=0.004) OR 2.79(1.46-5.42) and were associated with high risk of HCV infection. In silico sequence analysis showed the presence of ectropic viral integration site 1 encoded factor, in which G at -705 results in the loss of this site. The -7C/A polymorphism was not seen in our study cohort. The expression of TLR3 was upregulated in chronic HCV patients compared to healthy controls. Interpretation & conclusions: Polymorphism in the -705A/G allele at the promoter region of the TLR3 gene may predispose individual to HCV infection. However association of TLR3 expression with polymorphism of TLR3 promoter was not found.

Ribosomal Protein L19 and L22 Modulate TLR3 Signaling

BACKGROUND: Toll-like receptor 3 (TLR3) recognizes double-stranded RNA (dsRNA) and induces inflammation. In this study we attempted to ascertain if there are endogenous host molecules controlling the production of cytokines and chemokines. Two candidates, ribosomal protein L19 and L22, were analyzed to determine if they influence cytokine production followed by TLR3 activation. In this study we report that L19 acts upon production of IP-10 or IL-8 differently in glioblastoma cells. METHODS: L19 or L22 was transfected into HEK293-TLR3, A549 or A172 cells. After treatment with several inhibitors of NF-kB, PI3K, p38 or ERK, production of IL-8 or IP-10 was measured by ELISA. siRNA was introduced to suppress expression of L19. After Vesicular stomatitis virus infection, viral multiplication was measured by western blot. RESULTS: L19 increased ERK activation to produce IL-8. In A172 cells, in which TLR3 is expressed at endosomes, L19 inhibited interferon regulatory factor 3 (IRF3) activation and IP-10 production to facilitate viral multiplication, whereas L19 inhibited viral multiplication in A549 cells bearing TLR3 on their cell membrane. CONCLUSION: Our results suggest that L19 regulates TLR3 signaling, which is cell type specific and may be involved in pathogenesis of autoimmune diseases and chronic inflammatory diseases.

Role of Toll-like Receptor 3 Variants in Aspirin-Exacerbated Respiratory Disease

PURPOSE: Although the mechanism of virus-induced, aspirin-exacerbated respiratory disease (AERD) is not known fully, direct activation of viral components through Toll-like receptor 3 (TLR3) has been suggested. TLR3 recognizes double-stranded RNA (dsRNA), and activates nuclear factor-kappaB and increases interferon-gamma, which signals other cells to induce airway inflammation in asthma. Considering the association of TLR3 in viral infections and AERD, we investigated whether promoter and non-synonymous variants of TLR3 were associated with AERD. METHODS: The three study groups, 203 with AERD, 254 with aspirin-tolerant asthma (ATA), and 274 normal healthy controls (NC) were recruited from Ajou University Hospital, Korea. Two polymorphisms, -299698G>T and 293391G>A [Leu412Phe], were genotyped using primer extension methods. RESULTS: Genetic associations were examined between two genetic polymorphisms of TLR3 (-299698G>T and 293391G>A [Leu412Phe]) in the three study groups. AERD patients that carried the GG genotype of 293391G>A showed a significantly lower frequency compared with ATA in both co-dominant (P=0.025) and dominant models (P=0.036). Similarly, in the minor allele frequency, the A allele was significantly higher (P=0.023) in AERD compared with ATA for this polymorphism. AERD patients who carried HT2 [GA] showed a significantly higher frequency than other haplotypes in co-dominant (P=0.02) and recessive (P=0.026) models. CONCLUSIONS: Our findings suggest that the -299698G>T and 293391G>A [Leu412Phe] polymorphisms of the TLR3 gene are associated with the AERD phenotype.

The expression of Toil-like receptors-3 mRNA on peripheral blood monocytes in patients with primary biliary cirrhosis / 中华风湿病学杂志

Objective To explore the relationship of Toll-like receptors (TLR)-3 Mrna expression level on peripheral blood monocytes (PBMCs) with disease activity of PBC in patients with primary biliary cirrhosis (PBC). Methods The expression level of TLR-3 Mrna on peripheral blood monocytes was tested in 55 PBC cases (33 cases in active phase, 22 cases in stable stage), 20 cases with hepatoma (as disease controls) and 24 healthy controls. By real-time quantitative reverse transcription polymerase chain reaction (FQ-RT-PCR) methods. Β-actin was selected as the internal control. △Ct=Ct (target gene)-Ct(internal reference gene) were used to measure the gene expression level. Results The mean TLR-3 Mrna expression of PBC in active stage was higher than that of stable stage, hepatoma (P<0.001) as well as normals.The difference was significant (P=0.011<0.05). The mean TLR-3 Mrna was not different than that of the stable stage (P=0.221>0.05) and normal controls (P=0.347>0.05). There was no difference between patients with stable PBC and normal controls (P=0.590>0.05). Conclusion The TLR-3 Mrna expression level of PBMCs is elevated in active PBC patients. It may correlate with the pathogenesis and disease activity of PBC.

Recent Advance on Cellular Signal Transduction in Response to Virus Infections / 生物化学与生物物理进展

How the hosts recognize and clear invading viruses is one of the key issues in molecular immunology. Previous studies uncovered that many early antiviral proteins, such as Type Ⅰ interferons and PKR, are strongly induced upon virus infection. These proteins not only limit virus replication and spread or cause infected cells to undergo apoptosis, but also induce consequently expression of cytokines and chemokines to initiate acquired immunity. However, the immediate-early signaling events among host and virus interaction were largely unknown. In the past few years, there are great breakthroughs in this rapidly evolving field. TLR3 and RIG-I/MDA5 signaling pathways were shown to play a crucial regulatory role in antiviral processes. These pathways are essential for the vertebrate immune system to recognize and clear RNA virus with different strategies, which are integral parts of innate immune response and directly affect later-stage acquired immunity. The recent know-how on TLR3 and RIG-I/MDA5 signal transduction pathways and their roles in antiviral immunity were summarized.

Cloning of TLR3 Isoform

Toll-like receptor (TLR) 3 is a member of the TLR family that confers innate immunity by recognizing viral pathogens. Herein, we report that the TLR3 isoform is expressed on human primary cells and cell lines. This isoform has 2, 520 bp cDNAs compared to the 2, 712 bp of full cDNA, is produced by deletion of an intron-like sequence within exon 4 and is co-expressed with wild type TLR3 in primary human astrocytes and glioblastoma cell lines. This finding suggests the TLR3 isoform in astrocytes may have a different immunological role for binding ligands during the immune response in brain.