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C-type lectins in organisms play an important role in the process of innate immunity. In this study, a C-type lectin belonging to the DC-SIGN class of Micropterus salmoides was identified. MsDC-SIGN is classified as a type II transmembrane protein. The extracellular segment of MsDC-SIGN possesses a coiled-coil region and a carbohydrate recognition domain (CRD). The key amino acid motifs of the extracellular CRD of MsDC-SIGN in Ca2+-binding site 2 were EPN (Glu-Pro-Asn) and WYD (Trp-Tyr-Asp). MsDC-SIGN-CRD can bind to four pathogen-associated molecular patterns (PAMPs), including lipopolysaccharide (LPS), glucan, peptidoglycan (PGN), and mannan. Moreover, it can also bind to Gram-positive, Gram-negative bacteria, and fungi. Its CRD can agglutinate microbes and displays D-mannose and D-galactose binding specificity. MsDC-SIGN was distributed in seven tissues of the largemouth bass, among which the highest expression was observed in the liver, followed by the spleen and intestine. Additionally, MsDC-SIGN was present on the membrane of M. salmoides leukocytes, thereby augmenting the phagocytic activity against bacteria. In a subsequent investigation, the expression patterns of the MsDC-SIGN gene and key genes associated with the TLR signaling pathway (TLR4, NF-κB, and IL10) exhibited an up-regulated expression response to the stimulation of Aeromonas hydrophila. Furthermore, through RNA interference of MsDC-SIGN, the expression level of the DC-SIGN signaling pathway-related gene (RAF1) and key genes associated with the TLR signaling pathway (TLR4, NF-κB, and IL10) was decreased. Therefore, MsDC-SIGN plays a pivotal role in the immune defense against A. hydrophila by modulating the TLR signaling pathway. [ABSTRACT FROM AUTHOR]

Aims: Neuroblastoma (NB) is the most common extracranial solid tumor in children, with a 5‐year survival rate of <50% in high‐risk patients. MYCN amplification is an important factor that influences the survival rate of high‐risk patients. Our results indicated MYCN regulates the expression of SESN1. Therefore, this study aimed to investigate the role and mechanisms of SESN1 in NB. Methods: siRNAs or overexpression plasmids were used to change MYCN, SESN1, or MyD88's expression. The role of SESN1 in NB cell proliferation, migration, and invasion was elucidated. Xenograft mice models were built to evaluate SESN1's effect in vivo. The correlation between SESN1 expression and clinicopathological data of patients with NB was analyzed. RNA‐Seq was done to explore SESN1's downstream targets. Results: SESN1 was regulated by MYCN in NB cells. Knockdown SESN1 promoted NB cell proliferation, cell migration, and cell invasion, and overexpressing SESN1 had opposite functions. Knockdown SESN1 promoted tumor growth and shortened tumor‐bearing mice survival time. Low expression of SESN1 had a positive correlation with poor prognosis in patients with NB. RNA‐Seq showed that Toll‐like receptor (TLR) signaling pathway, and PD‐L1 expression and PD‐1 checkpoint pathway in cancer were potential downstream targets of SESN1. Knockdown MyD88 or TLRs inhibitor HCQ reversed the effect of knockdown SESN1 in NB cells. High expression of SESN1 was significantly associated with a higher immune score and indicated an active immune microenvironment for patients with NB. Conclusions: SESN1 functions as a new tumor suppressor gene via TLR signaling pathway in NB. [ABSTRACT FROM AUTHOR]

Toll‐like receptor 1 (TLR1) mediates the innate immune response to a variety of microbes through recognizing cell wall components (such as bacterial lipoproteins) in mammals. However, the detailed molecular mechanism of TLR1 involved in pathogen immunity in the representative hybrid yellow catfish (Pelteobagrus fulvidraco ♀ × P. vachelli ♂) has not been well studied. In the present study, we identified the TLR1 gene from the hybrid yellow catfish, and further comparative synteny data from multiple species confirmed that the TLR1 gene is highly conserved in teleosts. Phylogenetic analysis revealed distinguishable TLR1s in diverse taxa, suggesting consistence in evolution of the TLR1 proteins with various species. Structural prediction indicated that the three-dimensional structures of TLR1 proteins are relatively conserved among different taxa. Positive selection analysis showed that purifying selection dominated the evolutionary process of TLR1s and TLR1-TIR domain in both vertebrates and invertebrates. Expression pattern analysis based on the tissue distribution showed that TLR1 mainly transcribed in the gonad, gallbladder and kidney, and the mRNA levels of TLR1 in kidney were remarkably up-regulated after Aeromonas hydrophila stimulation, indicating that TLR1 participates in the inflammatory responses to exogenous pathogen infection in hybrid yellow catfish. Homologous sequence alignment and chromosomal location indicated that the TLR signaling pathway is very conserved in the hybrid yellow catfish. The expression patterns of TLR signaling pathway related genes (TLR1-TLR2 - MyD88 - FADD - Caspase 8) were consistent after pathogen stimulation, revealing that the TLR signaling pathway is triggered and activated after A. hydrophila infection. Our findings will lay a solid foundation for better understanding the immune roles of TLR1 in teleosts, as well as provide basic data for developing strategies to control disease outbreak in hybrid yellow catfish. [ABSTRACT FROM AUTHOR]

Seneca Valley virus (SVV), a member of the Picornaviridae family, is an oncolytic RNA virus that can cause idiopathic vesicular disease and increase mortality in newborn piglets. Although research on the pathogenic characteristics, epidemiology, pathogenic mechanism, and clinical diagnosis of SVA has increased due to its emergence and prevalence, the interaction between SVA and its host lncRNA has not been fully studied. This study used qualcomm sequencing to analyze differentially expressed lncRNAs and found that during SVA infection, lncRNA 8244 was significantly down-regulated in both PK-15 cells and piglets. Further analysis through quantitative real-time PCR and dual luciferase experiments demonstrated that lncRNA8244 could compete with ssc-miR-320 to regulate the expression of CCR7. The lncRNA824-ssc-miR-320-CCR7 axis activated the TLR-mediated signaling pathway, which recognized viral molecules and induced the expression of IFN-β. These findings provide new insight into the interaction between lncRNA and SVA infection, which could lead to a better understanding of SVA pathogenesis and contribute to the prevention and control of SVA disease. [ABSTRACT FROM AUTHOR]

Baylisascaris schroederi (B. schroederi) is a severe threat to the survival of giant pandas. Currently, the immune regulation mechanism of B. schroederi is poorly understood. Cysteine protease inhibitors (CPI) play important roles in the regulation of host immune responses against certain nematodes. In this study, a recombinant CPI of B. schroederi migratory larvae (rBsCPI-1) was cloned and expressed, and the effects of rBsCPI-1 on the physiological activities and antigen presentation of monocyte-derived macrophages (MDMs) were analyzed. We also analyzed the regulatory effects of rBsCPI-1 on the proliferation and differentiation of CD4+ T cells. And further identified the signaling pathways which play important roles in this process. The results showed that rBsCPI-1 activated the TLR2/4-small Rho GTPases-PAK1 pathway. On the one hand, it increased the phagocytosis and migration of MDMs. On the other hand, it activated downstream MAPK and NF-κB signaling pathways to induce apoptosis of MDMs. rBsCPI-1 also induced MDMs to polarize to the M2 subtype, thereby exerting an immunosuppressive effect. Meanwhile, rBsCPI-1 inhibited the antigen presentation process by decreasing the expression of MHC-II molecules, further inhibiting the proliferation of CD4+ T cells and inducing a Th1/Th2 mixed immune response. Treg cells with immunosuppressive effects were increased. The PD-L2/PD-1 and CD80/CTLA-4 signaling pathways between MDMs and CD4+ T cells were also activated by rBsCPI-1. In conclusion, this study preliminarily confirmed that rBsCPI-1 affects the physiological activities and polarization of MDMs through the TLR2/4 signaling pathway, and further interferes with antigen presentation response, inducing CD4+ T cells to play an immunosuppressive cellular response during the migratory process of B. schroederi. Thus, this study will provide a reference for elucidating the immune evasion mechanism of B. schroederi and developing new drugs and protective vaccines against B. schroederi.

One of the most lethal and aggressive types of malignancies with a high mortality rate and poor response to treatment is glioblastoma multiforme (GBM). This means that modernizing the medications used in chemotherapy, in addition to medicines licensed for use in other illnesses and chosen using a rationale process, can be beneficial in treating this illness. Meaningly, drug combination therapy with chemical or herbal originations or implanting a drug wafer in tumors to control angiogenesis is of great importance. Importantly, the primary therapeutic hurdles in GBM are the development of angiogenesis and the blood-brain barrier (BBB), which keeps medications from getting to the tumor. This malignancy can be controlled if the drug's passage through the BBB and the VEGF (vascular endothelial growth factor), which promotes angiogenesis, are inhibited. In this way, the effect of combination therapy on the genes of different main signaling pathways like TLRs may be indicated as an impressive therapeutic strategy for treating GBM. This article aims to discuss the effects of chemotherapeutic drugs on the expression of various genes and associated translational factors involved in the TLR signaling pathway. [Display omitted] [ABSTRACT FROM AUTHOR]

Viruses are obligate intracellular pathogens that rely on cellular machinery for successful replication and dissemination. The host cells encode a number of different strategies to sense and restrict the invading viral pathogens. Caspase‐mediated programmed cell death pathways that are triggered by virus infection, such as apoptosis and pyroptosis, provide a means for the infected cells to limit viral proliferation, leading to suicidal cell death (apoptosis) or lytic cell death and alerting uninfected cells to mount anti‐viral responses (pyroptosis). However, some viruses can employ activated caspases to dampen the anti‐viral responses and facilitate viral replication through cleavage of critical molecules of the innate immune pathways. The regulation of innate immune responses by caspase activation during virus infection has recently become an important topic. In this review, we briefly introduce the characteristics of different classes of caspases and the cell death pathways regulated by these caspases. We then describe how viruses trigger or dampen caspase activation during infection and how these activated caspases regulate three major innate immune response pathways of viral infections: the retinoic acid‐inducible gene I‐like receptor, toll‐like receptor and cyclic GMP‐AMP synthase‐stimulator of interferon genes pathways. [ABSTRACT FROM AUTHOR]

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Iron oxide nanoparticles (Fe2O3 NPs) is the main component of air pollution particles in urban rail transit environment. People are more exposed to Fe2O3 NPs, however, the studies on relationship between Fe2O3 NPs and respiratory health are limited. In the present study, acute airway inflammation caused by Fe2O3 NPs and its possible mechanism were investigated. BALB/c mice were intratracheally challenged with different concentrations of Fe2O3 NPs. Fe2O3 NPs induced bronchial epithelial barrier function damage, infiltration of neutrophils and lymphocytes into the airway submucosa, secretion of mucus in the airway epithelium and elevated expression of eosinophil major basic protein (EMBP) in lungs. Compared with the control group, Fe2O3 NPs increased eosinophils by 20 times in bronchoalveolar lavage fluid (BALF), and markedly increased eosinophils related cytokines and chemokines, including interleukin (IL) ‐5, IL‐33, thymic stromal lymphopoietin (TSLP), monocyte chemotactic protein (MCP)‐3, eotaxin, tumor necrosis factor (TNF)‐α, keratinocyte chemoattractant (KC). Furthermore, Fe2O3 NPs up‐regulated levels of IL‐5, MCP‐3, eotaxin, and KC in serum. In vitro studies showed that Fe2O3 NPs increased the genes and proteins expression of Toll‐like receptors (TLR)‐2, TLR4, TNF receptor associated factor 6 (TRAF6), myeloid differentiation factor 88 (MyD88), nuclear factor (NF)‐κB, and TNF‐α in RAW267.4 cells. The downstream inflammatory cytokine protein expression and release such as TNF‐α was significantly decreased after using TLR2/TLR4 inhibitor OxPAPC, but not MyD88 inhibitor ST2825. These results suggest that TLR2 and TLR4 played important role in Fe2O3 NPs inducing acute eosinophilic airway inflammation in the murine lung. [ABSTRACT FROM AUTHOR]

Seneca Valley virus (SVV), a member of the Picornaviridae family, is an oncolytic RNA virus that can cause idiopathic vesicular disease and increase mortality in newborn piglets. Although research on the pathogenic characteristics, epidemiology, pathogenic mechanism, and clinical diagnosis of SVA has increased due to its emergence and prevalence, the interaction between SVA and its host lncRNA has not been fully studied. This study used qualcomm sequencing to analyze differentially expressed lncRNAs and found that during SVA infection, lncRNA 8244 was significantly down-regulated in both PK-15 cells and piglets. Further analysis through quantitative real-time PCR and dual luciferase experiments demonstrated that lncRNA8244 could compete with ssc-miR-320 to regulate the expression of CCR7. The lncRNA824-ssc-miR-320-CCR7 axis activated the TLR-mediated signaling pathway, which recognized viral molecules and induced the expression of IFN-β. These findings provide new insight into the interaction between lncRNA and SVA infection, which could lead to a better understanding of SVA pathogenesis and contribute to the prevention and control of SVA disease.

• Gut microbiota differ significantly in UTI vs. healthy samples. • SA activates TLR, upregulating CXCL10, resisting antibiotics. • CXCL10 knockout in cells boosts SA's vancomycin sensitivity. • Knocking out CXCL10 lowers inflammation in SA UTI. • Study sheds light on antibiotic resistance in UTI patients. Glycopeptide antibiotic vancomycin is a bactericidal antibiotic available for the infection to Staphylococcus aureus (SA), however, SA has a strong adaptive capacity and thereby acquires resistance to vancomycin. This study aims to illuminate the possible molecular mechanism of vancomycin resistance of SA based on the 16S rRNA sequencing data and microarray profiling data. 16S rRNA sequencing data of control samples and urinary tract infection samples were retrieved from the EMBL-EBI (European Molecular Biology Laboratory - European Bioinformatics Institute) database. Correlation of gut flora and clinical indicators was evaluated. The possible targets regulated by SA were predicted by microarray profiling and subjected to KEGG (Kyoto Encyclopedia of Genes and Genomes) enrichment analysis. CXCL10 gene knockout and overexpression were introduced to evaluate the effect of CXCL10 on the virulence of SA and the resistance to vancomycin. SA strains were co-cultured with urethral epithelial cells in vitro. The presence of SA virulence factors was detected using PCR. Biofilm formation of SA strains was assessed using the microtiter plate method. Furthermore, the antibiotic sensitivity of SA strains was evaluated through vancomycin testing. Gut flora and its species abundance had significant difference between urinary tract infection and control samples. SA was significantly differentially expressed in urinary tract infection samples. Resistance of SA to vancomycin mainly linked to the D-alanine metabolism pathway. SA may participate in the occurrence of urinary tract infection by upregulating CXCL10. In addition, CXCL10 mainly affected the SA resistance to vancomycin through the TLR signaling pathway. In vitro experimental results further confirmed that the overexpression of CXCL10 in SA increased SA virulence and decreased its susceptibility to vancomycin. In vitro experimental validation demonstrated that the knockout of CXCL10 in urethral epithelial cells enhanced the sensitivity of Staphylococcus aureus (SA) to vancomycin. SA upregulates the expression of CXCL10 in urethral epithelial cells, thereby activating the TLR signaling pathway and promoting resistance to glycopeptide antibiotics in SA. [ABSTRACT FROM AUTHOR]

Background/Aims: Breast cancer (BC) starts as a local disease, but it can metastasize to the lymph nodes and distant organs. However, the metastatic process is still poorly understood. The mRNA microarray datasets GSE26910 and GSE33447 show that CXCL10 is up-regulated in BC, and the microRNA microarray dataset GSE38167 and a network meta-analysis of microRNA expression profile studies in human BC suggest that microRNA-34a (miR-34a) is down-regulated in BC. CXCL10 was predicted as a target of miR-34a by microRNA.org. In this study, we uncovered a CXCL10-independent mechanism by which miR-34a exerts its antimetastatic activity in BC. Methods: To investigate the clinical significance of miR-34a in BC, we collected cancer tissues and paracancerous tissues from 258 patients with BC. In addition, a series of inhibitors, mimics, and siRNAs was introduced into MCF-7 and T47D cells to validate the regulatory mechanisms by which miR-34a regulates CXCL10. Next, to better understand the pivotal role of TLR signaling pathway inhibition in MCF-7 and T47D cells, we blocked the TLR signaling pathway using OxPAPC, an antagonist of TLR signaling. Results: Among BC patients, miR-34a was down-regulated, CXCL10 was up-regulated, and the TLR signaling pathway was activated. Determination of luciferase activity revealed that CXCL10 was a target of miR-34a. Through gain- and loss-of-function studies, miR-34a was demonstrated to negatively regulate CXCL10; inhibit activation of the TLR signaling pathway; significantly suppress in vitro cell proliferation, migration, and invasion; and induce apoptosis. Conclusion: Our findings suggest that functional loss or suppression of the tumor suppressor CXCL10 due to induction of miR-34a leads to inhibition of the TLR signaling pathway during breast tumorigenesis, providing a novel target for the molecular treatment of breast malignancies.

Interleukin-1 receptor-associated kinases (IRAKs) play important roles in the innate immune system of TLR (Toll-like receptor) signaling pathway. In this paper, interleukin-1 receptor-associated kinase-b (designated as McIRAK-b) and interleukin-1 receptor-associated kinase-a (named as McIRAK-a) were obtained based on the transcriptome data, the full length of McIRAK-b was 1815 bp and McIRAK-a was 3168bp, encoding 532 and 978 amino acids, respectively. BLASTp analysis and phylogenetic relationship strongly suggested that the deduced amino acid sequence of McIRAK-b had high homology with IRAK-4 and McIRAK-a was similar to IRAK-1 of other mollusks, especially at their function domains. The expressions of McIRAK-b and McIRAK-a were detected in six tissues including adductor muscle, hemocyte, gills, gonad and hepatopancreas, and the highest expressions appeared both in gills. The expressions of McIRAK-b and McIRAK-a in gills were observed with time-dependent manners after bacterial infections. After being challenged with Vibrio alginolyticus , McIRAK-b expressed significantly and got the peak at 8 h (9.47 times compared with the control group), but the peak appeared at 4 h by being infected with Vibrio parahaemolyticus (12.02 times compared with the control group). The highest point of McIRAK-a mRNA appeared at 12 h (5.16 times) after being challenged with V.alginolyticus and 8 h (4.21 times) for V.parahaemolyticus challenge. The results suggested that IRAK-b and IRAK-a might be important in immune signaling pathway of mussels. The kinase functional domain sequences (S_TKc) of McIRAK-b and McIRAK-a expressed in BL21(DE3) and purified by Ni-NAT Superflow resin conforming to the expected molecular weight with many active sites for their conferring protein-protein interaction functions. This study may provide some further understandings of the regulatory mechanisms in the bivalve innate immune system for IRAKs family. • IRAK-b and IRAK-a were identified from Mytilus coruscus. • The functional domains and some crucial amino acids in two IRAKs were conserved. • They were constitutively expressed in different tissues but the highest was in gill. • Their temporal expressions were up-regulated under the stress of aquatic pathogens. • S_TKc in IRAKs were expressed and purified conforming to the expected molecular weight. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To clarify the effect of suppressor of cytokine signaling 1 (SOCS1) on diabetic nephropathy (DN)-induced renal injury by regulating the Toll-like receptor (TLR) signaling pathway. MATERIALS AND METHODS: The Sprague-Dawley rats were divided into control group (n=10) and DN group (established with streptozotocin injection, n=20). The DN rats were administrated with SOCS1 lentivirus to upregulate the in vivo expression. The rat blood glucose was detected to confirm the successful preparation of the DN model. The hepatic and renal function indexes, including blood urea nitrogen (BUN), alkaline phosphatase (ALP), alanine aminotransferase (ALT) and creatinine (CR) were detected. The pathological lesions in the kidney were observed via hematoxylin-eosin (HE) staining. Besides, the serum levels of the inflammatory factors in rats were detected via enzyme-linked immunosorbent assay (ELISA). The relative levels of genes in the TLR signaling pathway were detected via RT-PCR and Western blotting. RESULTS: The blood glucose level in rats of the DN group was significantly enhanced, indicating the successful modeling. The expression of SOCS1 was significantly upregulated in rats administrated with SOCS1 lentivirus. The contents of BUN, ALP, ALT, and CR in rats of SOCS1 overexpression group were significantly lower than those in the DN group. The inflammatory infiltration in the kidney and the glomerular injury were pronounced in the DN group. The serum levels of interleukin-1 (IL-1), interferon-γ (INF-γ), and tumor necrosis factor-α (TNF-α) were significantly declined in SOCS1 overexpression group. Besides, the mRNA expressions of myeloid differential protein- 88 (MyD88), TLR2, and INF-γ, and the protein expression of TLR2 were all remarkably downregulated in SOCS1 overexpression group. CONCLUSIONS: SOCS1 can promote renal injury repair in DN rats by inhibiting the TLR pathway. Therefore, SOCS1 is expected to be a new target for the repair of DN renal injury. [ABSTRACT FROM AUTHOR]

Abstract Triclocarban (TCC) is used in many household and personal hygiene products. TCC has been widely detected in wastewater around the world. The present study reveals that TCC can activate oxidative stress, induce total antioxidant capacity expression and lipid peroxidation, and increase the activities of superoxide dismutase and other antioxidant enzymes to resist oxidative damage. A significant induction of concentrations of proinflammatory mediator and nitric oxide (NO), accompanied by an upregulated expression of inducible NO synthase gene, was detected in zebrafish embryos exposed to TCC. The transcription of immune-response-related genes, including tnf-α , il-1β , il-4 , il-8 , and cxcl-clc , was significantly upregulated on exposure to TCC. Furthermore, we found that the exposure of zebrafish embryos to TCC decreased immune cell recruiting in the head. Expressions of nf-κb , trif , myd88 , irak4 , and traf6 were altered on exposure to TCC. These results demonstrated that exposure to TCC at environmental concentrations significantly affects the expression of immune-response-related genes in zebrafish embryos following oxidative stress and the release of proinflammatory mediators through Toll-like receptor signaling pathway. Thus, we assumed that the ecological risk of TCC on aquatic organisms could not be ignored. Highlights • Triclocarban (TCC) exposure induced oxidative stress in zebrafish larvae. • Low concentration of TCC increased the release of proinflammatory mediators. • The exposure of TCC affected innate immune response in zebrafish embryos. • Environmental concentration of TCC activated Toll-like receptor signaling pathway. [ABSTRACT FROM AUTHOR]

Background/Aims: Breast cancer (BC) starts as a local disease, but it can metastasize to the lymph nodes and distant organs. However, the metastatic process is still poorly understood. The mRNA microarray datasets GSE26910 and GSE33447 show that CXCL10 is up-regulated in BC, and the microRNA microarray dataset GSE38167 and a network meta-analysis of microRNA expression profile studies in human BC suggest that microRNA-34a (miR-34a) is down-regulated in BC. CXCL10 was predicted as a target of miR-34a by microRNA.org. In this study, we uncovered a CXCL10-independent mechanism by which miR-34a exerts its antimetastatic activity in BC. Methods: To investigate the clinical significance of miR-34a in BC, we collected cancer tissues and paracancerous tissues from 258 patients with BC. In addition, a series of inhibitors, mimics, and siRNAs was introduced into MCF-7 and T47D cells to validate the regulatory mechanisms by which miR-34a regulates CXCL10. Next, to better understand the pivotal role of TLR signaling pathway inhibition in MCF-7 and T47D cells, we blocked the TLR signaling pathway using OxPAPC, an antagonist of TLR signaling. Results: Among BC patients, miR-34a was down-regulated, CXCL10 was up-regulated, and the TLR signaling pathway was activated. Determination of luciferase activity revealed that CXCL10 was a target of miR-34a. Through gain- and loss-of-function studies, miR-34a was demonstrated to negatively regulate CXCL10; inhibit activation of the TLR signaling pathway; significantly suppress in vitro cell proliferation, migration, and invasion; and induce apoptosis. Conclusion: Our findings suggest that functional loss or suppression of the tumor suppressor CXCL10 due to induction of miR-34a leads to inhibition of the TLR signaling pathway during breast tumorigenesis, providing a novel target for the molecular treatment of breast malignancies. [ABSTRACT FROM AUTHOR]

Toll-like receptor (TLR) signaling pathway, composed of various components, plays pivotal roles in host innate immune defense mechanism. In the present study, twenty-nine TLR signaling pathway components, including receptors, adaptors, transduction molecules and immune effectors, were identified in Zhikong scallop Chlamys farreri via assembling and screening public available transcriptomic data and expression sequence tags (ESTs). These identified TLR signaling pathway components were constitutively expressed and detectable in various tissues, and almost all of them were highly expressed in gill and hepatopancreas. These results indicated the presence of TLR signaling pathways in both MyD88-dependent and MyD88-independent forms in scallop, and implied the diversified TLR signaling pathway in mollusk C. farreri . [ABSTRACT FROM AUTHOR]

Toll-like receptor 18 (TLR18), a non-mammalian TLR, has been believed to play an important role in anti-bacterial immunity of teleost fishes. UNC93B1 is a classical molecular chaperone that mediates TLRs transport from endoplasmic reticulum to the located membrane. However, TLR18-mediated signal transduction mechanism and the regulatory effect of UNC93B1 to TLR18 are still unclear in teleost fishes. In this study, the coding sequences of TLR18 and UNC93B1 were cloned from Schizothorax prenanti , named spTLR18 and spUNC93B1 , respectively. The spTLR18 and spUNC93B1 are 2583 bp and 1878 bp in length, encode 860 and 625 amino acids, respectively. The spTLR18 widely expressed in various tissues with the highest expression level in liver. After stimulation of Aeromonas hydrophila , lipopolysaccharide (LPS) and Poly(I:C), the expression levels of spTLR18 were significantly increased in spleen and head kidney. The spTLR18 located in the cell membrane, while spUNC93B1 located in the cytoplasm. Luciferase and overexpression analysis showed that spTLR18 activated NF-κB and type I IFN signal pathways, and spTLR18-mediated NF-κB activation might depend on the adaptor molecule MyD88. Besides, spUNC93B1 positively regulates spTLR18-mediated NF-κB signal. Our study first uncovers TLR18-UNC93B1-mediated signal transduction mechanism, which contributes to the understanding of TLR signaling pathway in teleost fishes. [Display omitted] • SpTLR18 responses to stimulation of LPS, Poly(I:C) and Aeromonas hydrophila in spleen and head kidney. • SpTLR18 may activate NF-κB and type I IFN signal pathways. • SpTLR18 may activate NF-κB via MyD88-dependent pathway. • SpUNC93B1 positively regulates spTLR18-mediated NF-κB signal. [ABSTRACT FROM AUTHOR]

Heat shock protein 70 (HSP70) is an important member of the heat shock protein superfamily and is involved in protecting organisms against various stressors. In the present study, we used RACE to clone a full-length Cyclina sinensis HSP70 cDNA termed CsHSP70 . The full length of the CsHSP70 cDNA was 2308 bp, with a 5′ untranslated region (UTR) of 42 bp, a 3′ UTR of 268 bp, and an open reading frame (ORF) of 1998 bp encoding a polypeptide of 655 amino acids with an estimated molecular mass of 72.75 kDa and an estimated isoelectric point of 5.48. Quantitative real-time PCR was employed to analyze the tissue distribution and temporal expression of the CsHSP70 gene after bacterial challenge and cadmium (Cd) exposure. The CsHSP70 mRNA transcript was expressed ubiquitously in five examined tissues, with the highest expression in hemocytes ( P < 0.05) and with the lowest expression in the hepatopancreas. Furthermore, the expression level of CsHSP70 in hemocytes at 3 h after Vibrio anguillarum challenge was extremely significantly up-regulated ( P < 0.01). Moreover, the CsHSP70 transcript was up-regulated significantly following exposure to a safe Cd concentration (0.1 mg/L). Finally, after the CsHSP70 gene was silenced by RNA interference, the expression of the CsTLR13 and CsMyD88 genes were extremely significantly decreased ( P < 0.01). The results indicated that CsHSP70 could play an important role in mediating the environmental stress and immune responses, and regulating TLR signaling pathway in C. sinensis . [ABSTRACT FROM AUTHOR]

Toll-like receptor 1 (TLR1) mediates the innate immune response to a variety of microbes through recognizing cell wall components (such as bacterial lipoproteins) in mammals. However, the detailed molecular mechanism of TLR1 involved in pathogen immunity in the representative hybrid yellow catfish ( Pelteobagrus fulvidraco ♀ × P. vachelli ♂ ) has not been well studied. In the present study, we identified the TLR1 gene from the hybrid yellow catfish, and further comparative synteny data from multiple species confirmed that the TLR1 gene is highly conserved in teleosts. Phylogenetic analysis revealed distinguishable TLR1s in diverse taxa, suggesting consistence in evolution of the TLR1 proteins with various species. Structural prediction indicated that the three-dimensional structures of TLR1 proteins are relatively conserved among different taxa. Positive selection analysis showed that purifying selection dominated the evolutionary process of TLR1s and TLR1-TIR domain in both vertebrates and invertebrates. Expression pattern analysis based on the tissue distribution showed that TLR1 mainly transcribed in the gonad, gallbladder and kidney, and the mRNA levels of TLR1 in kidney were remarkably up-regulated after Aeromonas hydrophila stimulation, indicating that TLR1 participates in the inflammatory responses to exogenous pathogen infection in hybrid yellow catfish. Homologous sequence alignment and chromosomal location indicated that the TLR signaling pathway is very conserved in the hybrid yellow catfish. The expression patterns of TLR signaling pathway related genes ( TLR1 - TLR2 - MyD88 - FADD - Caspase 8 ) were consistent after pathogen stimulation, revealing that the TLR signaling pathway is triggered and activated after A. hydrophila infection. Our findings will lay a solid foundation for better understanding the immune roles of TLR1 in teleosts, as well as provide basic data for developing strategies to control disease outbreak in hybrid yellow catfish., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Guo, Gao, Zeng, Liu, Yang, Chen, Wang, Jin, Xiang, Chen, Wen, Shi and Song.)

Toll-like receptor (TLR) signaling pathway plays a pivotal role in the innate immune system. Studies on TLR signaling pathway genes in Zhikong scallop ( Chlamys farreri) have mainly focused on sequence analysis and expression profiling, no research has been carried out on their localization. The chromosomal position of TLR signaling pathway genes can be valuable for assemblying scallop genome and analysizing gene regulatory networks. In the present study, five key TLR signaling pathway genes ( CfTLR, CfMyd88, CfTRAF6, CfNFκB, and CfIκB) containing bacterial artificial chromosomes (BACs) were isolated and physically mapped through fluorescence in situ hybridization on five non-homologous chromosome pairs, showing a similar distribution to another five model species. The isolation and mapping of these key immune genes of C. farreri will aid to the research on innate immunity, assignment of interested genes to chromosomes, and integration of physical, linkage and cytogenetic maps of this species. [ABSTRACT FROM AUTHOR]

Evolutionarily conserved signaling intermediate in Toll pathways (ECSIT) is a multifunctional adaptor protein that plays a key role in the regulation of the oxidative phosphorylation (OXPHOS) system, bone morphogenetic protein (BMP) pathway and Toll-like receptor (TLR) signaling pathway in mammals. However, the function of ECSIT homologs in mollusks, the second most diverse group of animals, is not well understood. In this study, we identified an ECSIT homolog in the Hong Kong oyster Crassostrea hongkongensis ( Ch ECSIT) and investigated its biological functions. The full-length cDNA of Ch ECSIT is 1734 bp and includes an open reading frame (ORF) of 1074 bp that encodes a polypeptide of 451 amino acids. The predicted Ch ECSIT protein shares similar structural characteristics with other known ECSIT family proteins. Quantitative real-time PCR analysis revealed that Ch ECSIT mRNA is broadly expressed in all of the examined tissues and at different stages of embryonic development; its transcript level could be significantly up-regulated by challenge with microorganisms ( Vibrio alginolyticus , Staphylococcus haemolyticus and Saccharomyces cerevisiae ). In addition, Ch ECSIT was found to be located primarily in the cytoplasm, and its overexpression stimulated the transcriptional activity of an NF-κB reporter gene in HEK293T cells. These findings suggest that Ch ECSIT might be involved in embryogenesis processes and immune responses in C. hongkongensis . [ABSTRACT FROM AUTHOR]

Autoimmune disorders are increasing worldwide. Although their pathogenesis has not been elucidated yet, a complex interaction of genetic and environmental factors is involved in their onset. Toll-like receptors (TLRs) represent a family of pattern recognition receptors involved in the recognition and in the defense of the host from invading microorganisms. They sense a wide range of pathogen associated molecular patterns (PAMPs) deriving from metabolic pathways selective of bacterial, viral, fungal and protozoan microorganisms. TLR activation plays a critical role in the activation of the downstream signaling pathway by interacting and recruiting several adaptor molecules. Although TLRs are involved in the protection of the host, several studies suggest that, in certain conditions, they play a critical role in the pathogenesis of autoimmune diseases. We review the most recent advances showing a correlation between some single nucleotide polymorphisms or copy number variations in TLR genes or in adaptor molecules involved in TLR signaling and the onset of several autoimmune conditions, such as Type I diabetes, autoimmune polyendocrinopathy candidiasis-ectodermal dystrophy, rheumatoid arthritis, systemic lupus erythematosus and systemic sclerosis. In light of the foregoing we finally propose that molecules involved in TLR pathway may represent the targets for novel therapeutic treatments in order to stop autoimmune processes. [ABSTRACT FROM AUTHOR]

Mesenchymal stem cells (MSCs) have been largely used for their immunomodulatory and regenerative properties in the treatment of immune-based disorders and bacterial infections. This study explores the function of MSC-derived extracellular vesicles (MSC-EVs) in alveolar epithelial type II cells (AECII) against Mycobacterium tuberculosis (MTB) infection. EVs were extracted from the acquired MSCs. AECII-like MLE-15 and A549 cells were treated with MSC-EVs and then subjected to MTB infection. MSC-EVs treatment significantly prevented the increase in bacterial load, and it prevented the production of proinflammatory cytokines in cells induced by MTB infection. MicroRNA-20b (miR-20b) was upregulated in cells after MSC-EVs treatment. Artificial inhibition of miR-20b blocked the protective effects of MSC-EVs against MTB infection. A Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis was performed to analyze the key molecules involved in the immune regulation in cells mediated by miR-20b. miR-20b directly targeted nuclear factor of activated T cells 5 (NFAT5) and inactivated the Toll-Like Receptor (TLR) signaling pathway by reducing the formation of TLR2-TLR4 dimer after MTB infection. In conclusion, this study suggests that MSC-EVs carry miR-20b to inhibit NFAT5 and inactivate the TLR signaling pathway, thus mediating innate immune response and preventing AECII from MTB infection-induced damage. • MTB infection reduces viability of the AECII. • miR-20b is upregulated in AECII after MSC-EVs treatment. • MSC-EVs prevent production of inflammatory factors in AECII through miR-20b. • miR-20b mediates the TLR signaling pathway by targeting NFAT5. • Silencing of NFAT5 enhances viability of AECII. [ABSTRACT FROM AUTHOR]

The innate immune system provides the first line of host defence against invading pathogens. Key to upregulation of the innate immune response are Toll-like receptors (TLRs), which recognize pathogen-associated molecular patterns (PAMPs) and trigger a signaling pathway culminating in the production of inflammatory mediators. Central to this TLR signaling pathway are heterotypic protein-protein interactions mediated through Toll/interleukin-1 receptor (TIR) domains found in both the cytoplasmic regions of TLRs and adaptor proteins. Pathogenic bacteria have developed a range of ingenuous strategies to evade the host immune mechanisms. Recent work has identified a potentially novel evasion mechanism involving bacterial TIR domain proteins. Such domains have been identified in a wide range of pathogenic bacteria, and there is evidence to suggest that they interfere directly with the TLR signaling pathway and thus inhibit the activation of NF-κB. The individual TIR domains from the pathogenic bacteria Salmonella enterica serovar Enteritidis, Brucella sp, uropathogenic E. coli and Yersinia pestis have been analyzed in detail. The individual bacterial TIR domains from these pathogenic bacteria seem to differ in their modes of action and their roles in virulence. Here, we review the current state of knowledge on the possible roles and mechanisms of action of the bacterial TIR domains. [ABSTRACT FROM AUTHOR]

Baylisascaris schroederi ( B. schroederi ) is a severe threat to the survival of giant pandas. Currently, the immune regulation mechanism of B. schroederi is poorly understood. Cysteine protease inhibitors (CPI) play important roles in the regulation of host immune responses against certain nematodes. In this study, a recombinant CPI of B. schroederi migratory larvae (rBsCPI-1) was cloned and expressed, and the effects of rBsCPI-1 on the physiological activities and antigen presentation of monocyte-derived macrophages (MDMs) were analyzed. We also analyzed the regulatory effects of rBsCPI-1 on the proliferation and differentiation of CD4+ T cells. And further identified the signaling pathways which play important roles in this process. The results showed that rBsCPI-1 activated the TLR2/4-small Rho GTPases-PAK1 pathway. On the one hand, it increased the phagocytosis and migration of MDMs. On the other hand, it activated downstream MAPK and NF-κB signaling pathways to induce apoptosis of MDMs. rBsCPI-1 also induced MDMs to polarize to the M2 subtype, thereby exerting an immunosuppressive effect. Meanwhile, rBsCPI-1 inhibited the antigen presentation process by decreasing the expression of MHC-II molecules, further inhibiting the proliferation of CD4+ T cells and inducing a Th1/Th2 mixed immune response. Treg cells with immunosuppressive effects were increased. The PD-L2/PD-1 and CD80/CTLA-4 signaling pathways between MDMs and CD4+ T cells were also activated by rBsCPI-1. In conclusion, this study preliminarily confirmed that rBsCPI-1 affects the physiological activities and polarization of MDMs through the TLR2/4 signaling pathway, and further interferes with antigen presentation response, inducing CD4+ T cells to play an immunosuppressive cellular response during the migratory process of B. schroederi . Thus, this study will provide a reference for elucidating the immune evasion mechanism of B. schroederi and developing new drugs and protective vaccines against B. schroederi ., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Xu, Gu, Xie, He, Xu, Xiong, Peng and Yang.)

Background: Recent studies showed that overwhelming inflammatory response mediated by the toll-like receptor (TLR)-related pathway was important in the development of acute lung injury (ALI). The aim of this study was to determine whether common genetic variation in four genes of the TLR signaling pathway were associated with sepsis-induced ALI susceptibility and risk of death in Chinese Han population. Methods: Fourteen tag single nucleotide polymorphisms (tagSNPs) in MyD88, IRAK1, IRAK4 and TRAF6 were genotyped in samples of sepsis-induced ALI (n = 272) and sepsis alone patients (n = 276), and tested for association in this case-control collection. Then, we investigated correlation between the associated SNP and the mRNA expression level of the corresponding gene. And we also investigated correlation between the associated SNP and tumor necrosis factor alpha (TNF-α) as well as interleukin-6 (IL-6) concentrations in peripheral blood mononuclear cells (PBMCs) exposed to lipopolysaccharides (LPS) ex vivo. The mRNA expression level was determined using real-time quantitative Polymerase Chain Reaction (PCR) assays, and concentrations of TNF-α and IL-6 were measured by enzyme-linked immunosorbent assay (ELISA). Results: The association analysis revealed that rs4755453, an intronic SNP of TRAF6, was significantly associated with susceptibility to sepsis-induced ALI. The C allele frequency of rs4755453 in the sepsis alone group was significantly higher than that in the sepsis-induced ALI group (P = 0.00026, odds ratio (OR) = 0.52, 95% confidence interval (CI) 0.37-0.74). These associations remained significant after adjustment for covariates in multiple logistic regression analysis and for multiple comparisons. TRAF6 mRNA expression levels in PBMCs from homozygotes of the rs4755453G allele were significantly higher than that in heterozygotes and homozygotes of the rs4755453C allele at baseline (P = 0.012 and P = 0.003, respectively) as well as after LPS stimulation (P = 0.009 and P = 0.005). Moreover, the concentrations of TNF-? and IL-6 in cell culture supernatants were also significantly higher in the subjects with rs4755453GG genotype than in subjects with CG and CC genotype. None of the 14 tagSNPs showed associations with risk of death and severity among ALI cases. Conclusions: Our findings indicated that common genetic variants in TRAF6 were significantly associated with susceptibility to sepsis-induced ALI in Chinese Han population. This was the first genetic evidence supporting a role for TRAF6 in ALI. [ABSTRACT FROM AUTHOR]

Abstract: As a member of pattern-recognition receptors (PRRs), the Toll-like receptor (TLR) and its signaling pathway play pivotal roles in recognizing various pathogen-associated molecular patterns (PAMPs), and buildup the front-line against invading pathogens. In the present study, the sequence features and mRNA expression profiles of five key genes involved in TLR signal pathway were characterized, and their functions in the immune responses were also investigated in order to validate the TLR signaling pathway and its potential roles in the immune defense of Zhikong scallop Chlamys farreri. These five genes, including CfTLR, CfMyD88, CfTRAF6, CfIκB and CfNFκB, exhibited significant similarity with their homologues from other model organisms, and contained the typical motifs. A strong interaction between the TIR domain from CfTLR and CfMyD88 protein was revealed via ELISA assays. The mRNA transcripts of these five genes were all up-regulated after LPS stimulation, indicating that they were involved in the immune response against LPS. When CfTLR expression was inhibited by RNAi technology, the mRNA expression level of CfMyD88, CfTRAF6, CfIκB, CfNFκB and G-type lysozyme were all decreased, while those of superoxide dismutase and catalase were increased. After Listonella anguillara challenge, the apoptosis level of those CfTLR-suppressed scallops was significantly lower than that in control groups (p <0.05) at the beginning of bacteria challenge, while the cumulative mortality was significantly higher than that of control groups (p <0.05). These results collectively favored that a rather canonical MyD88-dependent TLR pathway existed in scallop and this pathway was involved in immune signaling to active the diverse downstream reaction including anti-oxidant, anti-bacteria and apoptosis. [Copyright &y& Elsevier]

Abstract Background Recent studies showed that overwhelming inflammatory response mediated by the toll-like receptor (TLR)-related pathway was important in the development of acute lung injury (ALI). The aim of this study was to determine whether common genetic variation in four genes of the TLR signaling pathway were associated with sepsis-induced ALI susceptibility and risk of death in Chinese Han population. Methods Fourteen tag single nucleotide polymorphisms (tagSNPs) in MyD88, IRAK1, IRAK4 and TRAF6 were genotyped in samples of sepsis-induced ALI (n = 272) and sepsis alone patients (n = 276), and tested for association in this case-control collection. Then, we investigated correlation between the associated SNP and the mRNA expression level of the corresponding gene. And we also investigated correlation between the associated SNP and tumor necrosis factor alpha (TNF-α) as well as interleukin-6 (IL-6) concentrations in peripheral blood mononuclear cells (PBMCs) exposed to lipopolysaccharides (LPS) ex vivo. The mRNA expression level was determined using real-time quantitative Polymerase Chain Reaction (PCR) assays, and concentrations of TNF-α and IL-6 were measured by enzyme-linked immunosorbent assay (ELISA). Results The association analysis revealed that rs4755453, an intronic SNP of TRAF6, was significantly associated with susceptibility to sepsis-induced ALI. The C allele frequency of rs4755453 in the sepsis alone group was significantly higher than that in the sepsis-induced ALI group (P = 0.00026, odds ratio (OR) = 0.52, 95% confidence interval (CI) 0.37–0.74). These associations remained significant after adjustment for covariates in multiple logistic regression analysis and for multiple comparisons. TRAF6 mRNA expression levels in PBMCs from homozygotes of the rs4755453G allele were significantly higher than that in heterozygotes and homozygotes of the rs4755453C allele at baseline (P = 0.012 and P = 0.003, respectively) as well as after LPS stimulation (P = 0.009 and P = 0.005). Moreover, the concentrations of TNF-α and IL-6 in cell culture supernatants were also significantly higher in the subjects with rs4755453GG genotype than in subjects with CG and CC genotype. None of the 14 tagSNPs showed associations with risk of death and severity among ALI cases. Conclusions Our findings indicated that common genetic variants in TRAF6 were significantly associated with susceptibility to sepsis-induced ALI in Chinese Han population. This was the first genetic evidence supporting a role for TRAF6 in ALI.

• Stronger effects of EVs derived from F. prausnitzii. • EVs decrease inflammatory cytokines and increase anti-inflammatory cytokines. • Potential application of EVs in the treatment of inflammation. A single layer of epithelial cells creates an interface between the host and microorganisms colonizing the gastrointestinal tract. In a healthy intestine, commensal bacteria and their metabolites can interact with epithelial cells as they are identified by Toll-like receptors (TLRs); This interaction results in homeostasis and immune responses. The present study aimed at evaluating Faecalibacterium prausnitzii - and extracellular vesicles (EVs)-induced expression of involved genes in TLRs signaling pathway and cytokines production in Caco-2 cell line. In this study, Caco-2 cell line was treated with F. prausitzii and its EVs. Using the protein levels of 12 cytokines were also evaluated by ELISA assay. F. prausnitzii induced upregulation in FOS, JUN, TNF-α, NFKB1, TLR3, IKBKB and CD86 genes. Furthermore, stimulation of Caco-2 cells with EVs derived from F. prausnitzii induced upregulation of CXCL8, CCL2, FOS, MAP2K4, TLR7, TLR3, IRF1, NFKBIA and TNF-α genes. Based on ELISA assay, Caco-2 cells treated with F. prausnitzii and its EVs showed a significant increase in TNF-α, IL-4, IL-8, and IL-10 expression and significant decreased in IL-1, IL-2, IL-6, IL-12, IL-17a, IFN-γ compared to the control group (P < 0.05). In conclusion, EVs derived from F. prausnitzii showed greater efficacy in decreasing the inflammatory cytokines and increasing the anti-inflammatory cytokines, compared to F. prausnitzii. Our findings can be used as a theoretical model for EVs application in the potential treatment of inflammation. [ABSTRACT FROM AUTHOR]