Signaling pathways involved in inhibition of macrophage phagocytosis by TcpC of uropathogenic Escherichia coli / 中华微生物学和免疫学杂志

Objective:To investigate the signaling pathway of inhibiting macrophage phagocytosis of TIR domain-containing protein encoded by Escherichia coli (TcpC) N-terminal ubiquitin ligase active fragments of uropathogenic Escherichia coli. Methods:Bioinformatics software was used to analyze the amino acid sequences and the function of TcpC N-terminal ubiquitin ligase active fragments as well as the functional sites. PCR was performed to amplify tcpc-330, tcpc-450 and tcpc-510 genes and a prokaryotic expression system was constructed to express the target proteins. The recombinant proteins rTcpC-N110, rTcpC-N150 and rTcpC-N170 were purified by Ni-NTA affinity chromatography. LPS in the recombinant proteins was removed by Detoxi-gel chromatography. The expression of MyD88 at protein and mRNA levels in macrophages incubated with rTcpC-N110, rTcpC-N150, rTcpC-N170 or rTcpC-TIR was detected by Western blot and qRT-PCR. The activation of NF-κB signal pathway and the levels of proinflammatory factors in macrophages incubated with the above TcpC protein fragments were measured by Western blot and ELISA, respectively. Results:Cys12, Trp104 and Trp106 in the N-terminal fragment of TcpC were crucial amino acids in maintaining its ubiquitin ligase activity. The target recombinant proteins rTcpC-N110, rTcpC-N150 and rTcpC-N170 were successfully expressed and purified. After Detoxi-gel chromatography, rTcpC-N110, rTcpC-N150 and rTcpC-N170 extracts were undetectable for LPS. TcpC ubiquitin ligase fragments inhibited the expression of MyD88 at protein level, but not affect its expression at mRNA level in macrophages. LPS-induced phosphorylation of NF-κB signaling pathway-related proteins p50 and p65 was significantly inhibited in macrophages treated with TcpC ubiquitin ligase fragments. Moreover, LPS-induced production of pro-inflammatory factors was also significantly inhibited.Conclusions:The recombinant proteins rTcpC-N110, rTcpC-N150 and rTcpC-N170 could inhibit the expression of MyD88 at protein level and suppress the activation of NF-κB signaling pathway, suggesting that they were closely related to the inhibition of innate immune activity of macrophages.

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.

Mechanism of signal transduction in distant organ injuries induced by intestinal ischemia/reperfusion / 中华临床营养杂志

Objective To investigate the effect of different antibodies on Toll-like Receptor 4-High Mobility Group Box 1 and its downstream signal transductions in distant organ injuries caused by intestinal ischemia/reperfusion in mice.Methods A total of 40 mice (C57BL/6,SPF level) were by random number table method assigned into five groups:sham,control,anti-HMGB1,anti-Myeloid differentitation gene,and antiTIR domain containing adaptor inducing IFN-β (n=8).In the control,anti-HMGB1,anti-MyD88,and antiTRIF groups,the IgG,HMGB1,MyD88,and TRIF antibodies were injected,respectively,via the tail vein 30 minutes before ischemia (1 mg/kg body weight,0.025％).After anesthesia and abdomen incision,all mice,except the sham group,underwent intestinal ischemia by clamping the superior mesenteric artery for 60 minutes followed by 60 minutes of reperfusion.Sham group underwent the same surgical procedures except for clamping the artery.Serum nuclear factor-κB p65,Interleukin-6 and Tumor Necrosis Factor-α were measured.Morphological changes in the lung and intestine were evaluated.mRNA and protein expressions of HMGB1 and NF-κB in lung and intestinal tissues were assayed.Results Compared with the control group [(228.53± 24.85),(104.91±31.18),and (70.81±46.97) ng/L],HMGB1 [(145.00±33.63),(62.28±6.73),and (52.76± 5.71) ng/L],MyD88 [(191.12± 13.22),(85.90± 17.37),and (63.19 ± 5.47) ng/L],and TRIF [(183.73±10.81),(78.14±7.38),and (59.70±4.63) ng/L] significantly decreased the serum level of NF-κB (P=0.000,0.005,0.001),IL-6 (P=0.000,0.004,0.000) and TNF-α (P=0.000,0.024,0.002) after ischemia reperfusion.Tissue injuries in the lung and intestine were also alleviated by HMGB1,MyD88,and TRIF.The anti-HMGB1,anti-MyD88,and anti-TRIF groups displayed significant elevations of HMGB1 mRNA [lung (1.89±0.18),(2.35±0.31),and (2.29±0.28),ileum (4.93±0.55),(5.96± 0.73),and (5.76±0.51)],NF-κB mRNA [lung (1.42±0.23),(1.77±0.18) and (1.70±0.13),ileum (2.23±0.55),(3.11±0.38) and (2.99±0.24)] and NF-κB protein expressions in lung and ileum tissues compared to the sham group [lung HMGB1 mRNA (1.04±0.19) (P=0.000,0.000,0.000),NF-κBmRNA (1.03±0.21) (P=0.004,0.000,0.000),ileum HMGB1 mRNA (1.14±0.54) (P=0.000,0.000,0.000),NF-κB mRNA (1.03±0.23) (P=0.000,0.000,0.000)].However,incornparison with the control group [lung HMGB1 mRNA (2.67±0.23) (P=0.000,0.035,0.016),NF-κB mRNA (2.04±0.29) (P=0.000,0.039,0.012),ileum HMGB1 mRNA (6.70±0.66) (P=0.001,0.038,0.015),NF-κBmRNA (3.71±0.53) (P=0.000,0.018,0.006)],the other three groups showed a significant down-regulation,with the most remarkable decrement in the anti-HMGB1 group.Application of anti-HMGB1,anti-MyD88,and anti-TRIF could drastically attenuate the tissue injuries in ischemia reperfusion.anti-HMGB1 exhibited the most significant effect.Conclusions HMGB1 and its downstream signals play an important role in intestinal ischemia reperfusion injuries in mice.Of two downstream signals,the TRIF-dependent pathway exerts a more important effect than that of the MyD88-dependent pathway.

Effect of ethanol extracts from Polygonum multiflorum Thunb on expressions of signal pathway TLR4/TRIF/IRF-3 in LPS induced rats liver / 国际药学研究杂志

Objective To research the toxicity of ethanol extracts from Poylgonum multiflorum Thunb (PMT) induced by endotoxin of Gram-negative bacteria lipopolysaccharide (LPS) in rat liver, and then investigate the hepatotoxicity mechanisms of PMT on immune inflammatory signal pathway Toll-Like receptor 4 (TLR4) -interferon regulated factor3 (IRF-3). Methods SD rats were randomly assigned into normal control, LPS (4 mg/kg), acetaminophen APAP (625 mg/kg), PMT 6 g/kg (PMT- L), PMT 12 g/kg (PMT-H), LPS+APAP and LPS+PMT-L/-H groups. The 4 groups later were injected LPS 4 mg/kg by caudal vein, after 2 h, the corresponding drugs were administered once a day for 7 consecutive days, respectively. The changes of weight of rats were observed every day. The tissue morphology of liver tissue of rats on 2 h, 14 h, 5 d, 8 d after administration were detected by hematoxylin-eosin staining respectively. Real time quantitative PCR (RT-qPCR) method and Western blotting were used to detect the expression of TLR4, TRIF and IRF3 in the TLR4 signaling pathway in liver cells. Results Two hours after the rat tail vein injection of LPS, the liver tiny granulomas of rats could be observed in LPS-induced groups, and then, the liver injury of rats in LPS group was gradually recovered. Eight Days after LPS induction, the liver tissue structure of rats in LPS group was clear and complete, but in LPS + APAP group and LPS + PMT 6 or 12 g/kg groups, the focal necrosis of hepatocytes, with inflammatory cell infiltration could be observed. The results of RT-qPCR and Western blotting showed that in oral administration of PMT groups, the expression of TLR4, TRIF and IRF-3 mRNA and protein in the liver cells had no significant change compared with the normal control group. But in 4 groups induced with LPS, the expression of TLR4, TRIF and IRF- 3 mRNA and protein in the liver cells were significantly higher than that of the normal control group and LPS group (P<0.05). Conclusion PMT can cause liver damage induced by LPS, the hepatotoxicity is related to the positive regulation of TLR4/IRF-3 signaling pathways, which is not related to the dosage of PMT. The results show that activating TLR4/IRF3 signaling pathway is one of the mechanisms of liver injury of PMT in rats induced by LPS.

Effect of ethanol extracts from Polygonum multiflorum Thunb on expressions of signal pathway TLR4/TRIF/IRF-3 in LPS induced rats liver / 国际药学研究杂志

Objective To research the toxicity of ethanol extracts from Poylgonum multiflorum Thunb(PMT)induced by en?dotoxin of Gram-negative bacteria lipopolysaccharide(LPS)in rat liver,and then investigate the hepatotoxicity mechanisms of PMT on immune inflammatory signal pathway Toll-Like receptor 4(TLR4)-interferon regulated factor3(IRF-3). Methods SD rats were randomly assigned into normal control,LPS(4 mg/kg),acetaminophen APAP(625 mg/kg),PMT 6 g/kg(PMT-L),PMT 12 g/kg (PMT-H),LPS+APAP and LPS+PMT-L/-H groups. The 4 groups later were injected LPS 4 mg/kg by caudal vein,after 2 h,the corre?sponding drugs were administered once a day for 7 consecutive days,respectively. The changes of weight of rats were observed every day. The tissue morphology of liver tissue of rats on 2 h,14 h,5 d,8 d after administration were detected by hematoxylin-eosin stain? ing respectively. Real time quantitative PCR(RT-qPCR)method and Western blotting were used to detect the expression of TLR4, TRIF and IRF3 in the TLR4 signaling pathway in liver cells. Results Two hours after the rat tail vein injection of LPS,the liver tiny granulomas of rats could be observed in LPS-induced groups,and then,the liver injury of rats in LPS group was gradually recovered. Eight Days after LPS induction,the liver tissue structure of rats in LPS group was clear and complete,but in LPS+APAP group and LPS+PMT 6 or 12 g/kg groups,the focal necrosis of hepatocytes,with inflammatory cell infiltration could be observed. The results of RT-qPCR and Western blotting showed that in oral administration of PMT groups,the expression of TLR4,TRIF and IRF-3 mRNA and protein in the liver cells had no significant change compared with the normal control group. But in 4 groups induced with LPS,the expression of TLR4, TRIF and IRF-3 mRNA and protein in the liver cells were significantly higher than that of the normal control group and LPS group(P<0.05). Conclusion PMT can cause liver damage induced by LPS,the hepatotoxicity is related to the positive regulation of TLR4/IRF-3 signaling pathways,which is not related to the dosage of PMT. The results show that activating TLR4/IRF3 signaling pathway is one of the mechanisms of liver injury of PMT in rats induced by LPS.

Análisis genómioo-funcional de proteínas con dominios tir en yuca / Functional Genomic Analysis of Cassava Proteins with TIR domains

Dentro de las proteínas implicadas en inmunidad de plantas y animales se encuentran aquellas que poseen un dominio TIR (Toll Interleukin Receptor). El objetivo de este trabajo fue realizar un análisis genómico global de las proteínas que presentan un dominio TIR en yuca y discernir su posible función en la resistencia a la bacteriosis vascular. En el proteoma de yuca se logró identificar 46 proteínas con dominios TIR, los cuales fueron divididos en cuatro categorías según la presencia o no de otros dominios: TIR (T), TIR- NB (TN), TIR-LRR (TL) y TIR-NB-LRR (TNL). El 56,5 % de las 46 proteínas corresponde a la categoría TNL. Mediante alineamientos múltiples se encontró que no todos los dominios TIR de yuca presentan la región aE implicada en la dimerización y activación de las respuestas de inmunidad. Tres de las cuatro categorías de proteínas (T, TNL y TN) presentan un mayor número de sustituciones sinónimas, sugiriendo que no están implicadas en procesos de reconocimiento. Por medio de doble híbrido de levadura y agroinfiltración se analizaron dos dominios TIR que no presentan la región aE, encontrando que ambos son capaces de formar homo y heterodímeros pero no desencadenan respuestas de defensa. Con este trabajo se pudo concluir que algunas proteínas que poseen dominios TIR pueden funcionar como adaptadores en la transducción de la señal con otras proteínas de resistencia. Además, se puso en evidencia que no siempre la región aE es importante para la dimerización, pero sí para activar las señales de respuestas de defensa.

Proteins containing a TIR domain (Toll Interleukin Receptor) are involved in plant and animal immunity. The aim of this work was to carry out an overall genomic analysis of cassava proteins with a TIR domain and discern their possible role in resistance to cassava bacterial blight. In total 46 proteins with a TIR domain were identified in the cassava proteome and were classed in four categories according the presence or absence of other domains: TIR (T), TIR-NB (TN), TIR-LRR (TL) and TIR-NB-LRR (TNL). 56.6 % of these 46 proteins have TIR, NB and LRR domains. Using multiple alignments it was possible to demonstrate that not all cassava TIR domains contain the aE region, involved in dimerization and activation of immune responses. Three of the four proteins categories (T, TNL and TN) presented a higher number of synonymous substitutions suggesting that they are not involved in recognition process. Two TIR domains not presenting the aE region were analyzed by yeast two hybrid assays and by agroinfiltration, finding that both are able to form homo and heterodimers, but they do not trigger defense responses. With this study it was possible to conclude that TIR domains can function as adaptors in the signal transduction with other resistance proteins. In addition, it became clear that not always the aE region is important for TIR dimerization but it seems necessary to activate defense responses signals.