MyD88 Signaling Pathway Research Articles

The innate immune regulator MyD88 dampens fibrosis during zebrafish heart regeneration

The innate immune response is triggered rapidly after injury and its spatiotemporal dynamics are critical for regeneration; however, many questions remain about its exact role. Here we show that MyD88, a key component of the innate immune response, controls not only the inflammatory but also the fibrotic response during zebrafish cardiac regeneration. We find in cryoinjured myd88−/− ventricles a significant reduction in neutrophil and macrophage numbers and the expansion of a collagen-rich endocardial population. Further analyses reveal compromised PI3K/AKT pathway activation in the myd88−/− endocardium and increased myofibroblasts and scarring. Notably, endothelial-specific overexpression of myd88 reverses these neutrophil, fibrotic and scarring phenotypes. Mechanistically, we identify the endocardial-derived chemokine gene cxcl18b as a target of the MyD88 signaling pathway, and using loss-of-function and gain-of-function tools, we show that it controls neutrophil recruitment. Altogether, these findings shed light on the pivotal role of MyD88 in modulating inflammation and fibrosis during tissue regeneration.

Rabies Virus Regulates Inflammatory Response in BV-2 Cells through Activation of Myd88 and NF-κB Signaling Pathways via TLR7.

Rabies is a fatal neurological infectious disease caused by rabies virus (RABV), which invades the central nervous system (CNS). RABV with varying virulence regulates chemokine expression, and the mechanisms of signaling pathway activation remains to be elucidated. The relationship between Toll-like receptors (TLRs) and immune response induced by RABV has not been fully clarified. Here, we investigated the role of TLR7 in the immune response induced by RABV, and one-way analysis of variance (ANOVA) was employed to evaluate the data. We found that different RABV strains (SC16, HN10, CVS-11) significantly increased CCL2, CXCL10 and IL-6 production. Blocking assays indicated that the TLR7 inhibitor reduced the expression of CCL2, CXCL10 and IL-6 (p < 0.01). The activation of the Myd88 pathway in BV-2 cells stimulated by RABV was TLR7-dependent, whereas the inhibition of Myd88 activity reduced the expression of CCL2, CXCL10 and IL-6 (p < 0.01). Meanwhile, the RABV stimulation of BV-2 cells resulted in TRL7-mediated activation of NF-κB and induced the nuclear translocation of NF-κB p65. CCL2, CXCL10 and IL-6 release was attenuated by the specific NF-κB inhibitor used (p < 0.01). The findings above demonstrate that RABV-induced expression of CCL2, CXCL10 and IL-6 involves Myd88 and NF-κB pathways via the TLR7 signal.

Innate Immune Sensing of Adeno-Associated Virus Vectors.

Adeno-associated virus (AAV) based viral vectors are widely used in human gene therapy and form the basis of approved treatments for several genetic diseases. Immune responses to vector and transgene products, however, substantially complicate these applications in clinical practice. The role of innate immune recognition of AAV vectors was initially unclear, given that inflammatory responses early after vector administration were typically mild in animal models. However, more recent research continues to identify innate immune pathways that are triggered by AAV vectors and that serve to provide activation signals for antigen-presenting cells and initiation of adaptive immune responses. Sensing of the AAV genome by the endosomal DNA receptor toll-like receptor 9 (TLR9) promotes early inflammatory response and interferon expression. Thus, activation of the TLR9>MyD88 pathway in plasmacytoid dendritic cells (pDCs) leads to the conditioning of antigen cross-presenting DCs through type I interferon (IFN-I) and ultimately CD8+ T cell activation. Alternatively, pDCs may also promote CD8+ T cell responses in a TLR9-independent manner by the production of IL-1 cytokines, thereby activating the IL-1R1>MyD88 signaling pathway. AAV can induce cytokine expression in monocyte-derived DCs, which in turn increases antibody formation. Binding of AAV capsid to complement components likely further elevates B cell activation. At high systemic vector doses in humans and in non-human primates, AAV vectors can trigger complement activation, with contributions by classical and alternative pathways, leading to severe toxicities. Finally, evidence for activation of TLR2 by the capsid and of additional innate receptors for nucleic acids has been presented. These observations show that AAV vectors can initiate several and likely redundant innate immune pathways resulting in an exaggerated adaptive immune response.

MyD88 Inhibition Attenuates Cerebral Ischemia-reperfusion Injury by Regulating the Inflammatory Response and Reducing Blood–brain Barrier Damage

Myeloid differentiation primary response gene 88 (MyD88), a downstream molecule directly linked to Toll-like receptor (TLRs) and IL1 receptor, has been implicated in ischemia-reperfusion injury across various organs. However, its role in cerebral ischemia-reperfusion injury (CIRI) remains unclear. Five transient middle cerebral artery occlusion (tMCAO) microarray datasets were obtained from the Gene Expression Omnibus (GEO) database. We screened these datasets for differentially expressed genes (DEGs) using the GSE35338 and GSE58720 datasets and performed weighted gene co-expression network analysis (WGCNA) using the GSE30655, GSE28731, and GSE32529 datasets to identify the core module related to tMCAO. A protein–protein interaction (PPI) network was constructed using the intersecting DEGs and genes in the core module. Finally, we identified Myd88 was the core gene. In addition, Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Set Enrichment Analysis (GSEA) validated that TNFα, IL17, and MyD88 signaling pathways were significantly enriched in tMCAO. Subsequently, we investigated the mechanistic role of MyD88 in the tMCAO model using male C57BL/6 mice. MyD88 expression increased significantly 24 h after reperfusion. After intraperitoneal administration of TJ-M2010-5, a MyD88-specific inhibitor, during reperfusion, the infarction volumes in the mice were ameliorated. TJ-M2010-5 inhibits the activation of microglia and astrocytes. Moreover, it attenuates the upregulation of inflammatory cytokines TNFα, IL17, and MMP9 while preserving the expression level of ZO1 after tMCAO, thereby safeguarding against blood-brain barrier (BBB) disruption. Finally, our findings suggest that MyD88 regulates the IRAK4/IRF5 signaling pathway associated with microglial activation. MyD88 participates in CIRI by regulating the inflammatory response and BBB damage following tMCAO.

MyD88 signaling pathways: role in breast cancer.

MyD88 plays a central role in breast cancer, exerting a multitude of effects that carry substantial implications. Elevated MyD88 expression is closely associated with aggressive tumor characteristics, suggesting its potential as a valuable prognostic marker and therapeutic target. MyD88 exerts influence over several critical aspects of breast cancer, including metastasis, recurrence, drug resistance, and the regulation of cancer stem cell properties. Furthermore, MyD88 modulates the release of inflammatory and chemotactic factors, thereby shaping the tumor's immune microenvironment. Its role in immune response modulation underscores its potential in influencing the dynamic interplay between tumors and the immune system. MyD88 primarily exerts intricate effects on tumor progression through pathways such as Phosphoinositide 3-kinases/Protein kinase B (PI3K/Akt), Toll-like Receptor/Nuclear Factor Kappa B (TLR/NF-κB), and others. Nevertheless, in-depth research is essential to unveil the precise mechanisms underlying the diverse roles of MyD88 in breast cancer. The translation of these findings into clinical applications holds great promise for advancing precision medicine approaches for breast cancer patients, ultimately enhancing prognosis and enabling the development of more effective therapeutic strategies.

Functions and Clinical Relevance of Liver-Derived Immunoglobulins.

Liver is the largest internal organ of the body with vital functions. In addition to its endocrine and exocrine activities, liver also plays a pivotal role in the immune system, including haematopoietic functions. Liver parenchymal cells, which are epithelial cells, have been found to possess innate immune functions by expressing pattern-recognition receptors (PRRs), producing complement components, and secreting cytokines. Intriguingly, in recent years, it has been discovered that liver epithelial cells also produce immunoglobulins (Igs), which have long been thought to be produced exclusively by B cells. Notably, even liver epithelial cells from B lymphocyte-deficient mice, including SCID mice and μMT mice, could also produce Igs. Compelling evidence has revealed both the physiological and pathological functions of liver-derived Igs. For instance, liver epithelial cells-derived IgM can serve as a source of natural and specific antibodies that contribute to innate immune responses, while liver-produced IgG can act as a growth factor to promote cell proliferation and survival in normal hepatocytes and hepatocarcinoma. Similar to that in B cells, the toll-like receptor 9 (TLR9)-MyD88 signaling pathway is also actively involved in promoting liver epithelial cells to secrete IgM. Liver-derived Igs could potentially serve as biomarkers, prognostic indicators, and therapeutic targets in the clinical setting, particularly for liver cancers and liver injury. Nevertheless, despite significant advances, much remains unknown about the mechanisms governing Ig transcription in liver cells, as well as the detailed functions of liver-derived Igs and their involvement in diseases and adaptive immunity. Further studies are still needed to reveal these underlying, undefined issues related to the role of liver-derived Igs in both immunity and diseases.

Retracted: Antiulcerogenic Activity of Li-Zhong Decoction on Duodenal Ulcers Induced by Indomethacin in Rats: Involvement of TLR-2/MyD88 Signaling Pathway.

[This retracts the article DOI: 10.1155/2020/6538156.].

The intestinal microbiota exerts a sex-specific influence on neuroinflammation in a Parkinson's disease mouse model

Parkinson's disease (PD) is a neurodegenerative disorder characterised by chronic and progressive symptoms; it is more prevalent in men than in women. The sex-specific influence of the intestinal microbiota has been associated with some neurodegenerative diseases, but the relationship with PD is currently unclear. In this study, we treated mice with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) to establish a PD mouse model, and we utilised an antibiotic cocktail (Abx) to deplete the intestinal microbiota to evaluate the influence of the intestinal microbiota on male and female PD mice. MPTP treatment obviously caused bradykinesia and low mobility in female and male mice. Meanwhile, Abx treatment exerted a greater effect on male mice than female mice. Western blotting and immunofluorescence revealed that male mice treated with MPTP had higher expression of α-synuclein and proteins related to neuroinflammation and intestinal inflammation based on activation of glial cells and the TLR4–MyD88 signalling pathway. The sex-specific differences could be due to the different composition of the intestinal microbiota. Specifically, female mice had significantly higher abundance of Allobaculum, Turicibacter and Ruminococcus than male mice. Moreover, the abundance of the probiotic genus Bifidobacterium showed opposite trends in male and female mice. Our results indicate that the intestinal microbiota has an important effect on PD mice, especially male mice, by influencing neuroinflammation through the microbiota–gut–brain axis. In the future, there should be a focus on providing more reliable evidence for the pathogenesis and precise treatment of PD.

MDSC suppresses T cell antitumor immunity in CAC via GPNMB in a MyD88-dependent manner.

Myeloid-derived suppressor cells (MDSCs) played an essential role in tumor microenvironment to suppress host antitumor immunity and help cancer cells escape immune surveillance. However, the molecular mechanism behind tumor evasion mediated by MDSCs is not fully understood. Glycoprotein nonmetastatic melanoma protein B (GPNMB) is considered to associate with tumor initiation, metastasis and angiogenesis. Blocking GPNMB function is a potentially valuable therapy for cancer by eliminating GPNMB+MDSCs. Our previous study has proved that blockage the MyD88 signaling with the MyD88 inhibitor, TJ-M2010-5, may completely prevent the development of CAC in mice, accompanying with downregulation of GPNMB mRNA in the inhibitor-treated mice of CAC. We here focus on the underlying the relationship between GPNMB function and MyD88 signaling pathway activation in MDSCs' antitumor activity in CAC. CAC development in the mouse model is associated with expanded GPNMB+MDSCs by a MyD88-dependent pathway. The GPNMB expression on MDSCs is associated with MyD88 signaling activation. The inhibitory effect of MDSCs on T cell proliferation, activation and antitumor cytotoxicity in CAC is mediated by GPNMB in a MyD8-dependent manner. MyD88 signaling pathway plays an essential role in GPNMB+MDSC-mediated tumor immune escape during CAC development and is a promising focus for revealing the mechanisms of MDSC that facilitate immunosuppression and tumor progression.

Regulation of Nur77-TLR4/MyD88 signaling pathway is required for Ginsenoside Rc ameliorates hepatic fibrosis regression by deactivating hepatic stellate cells

HSCs (hepatic stellate cells) contribute to the excessive extracellular matrix (ECM) deposition plays a key role in the progression of hepatic fibrosis. The present study focused on the hepatoprotective effect of Ginsenoside Rc (Rc), one of the protopanaxadiol type ginsenoside, which has contributed to reverse activated HSCs to improve hepatic fibrosis via regulating Nur77-TLR4/MyD88 signaling pathway. We established the hepatic fibrosis model by intraperitoneal injection of carbon tetrachloride (CCl4). And HSCs were stimulated with TGF-β, followed by silencing of Nur77, and then incubated in Rc. Rc significantly alleviated histopathological changes, reduced serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels. Rc could upregulate the Nur77 and downregulate fibrosis markers in the liver of mice, including decreasing the expressions of α-SMA, Collagen-I, the ratio of TIMP-1/MMP-13. Rc significantly increased the expression of Nur77 and suppressed the production of ECM in HSCs. Rc inhibited TLR4 signaling pathway, consequently reversing the inflammatory response, including the production of MyD88, IRAK1, IRAK4 and IL-23. When Nur77 was knocked in TGF-β-stimulated HSCs, TLR4 and α-SMA production were increased. Rc suppressed these activatory effects in Nur77 knockdown HSCs. Rc reduced inflammatory reaction by regulating the Nur77-TLR4 signaling pathway while suppressing the fibrogenesis suggesting, underscoring a promising approach of Rc for the treatment in hepatic fibrosis. Targeting Nur77-TLR4 signaling in HSCs would be the potential strategy for Rc against hepatic fibrosis.

WITHDRAWN: LncRNA-PVT1 Inhibition Protects Neuron Injury During Cerebral Ischemia Injury through Targeting the miRNA-187-3p- MyD88 Signaling Pathway

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OncoTherad immunotherapy plus platelet rich plasma as potential therapeutic strategy for ovarian cancer: The role of toll-like receptors 2 and 4 signaling pathways.

e17602 Background: Ovarian cancer (OC) has the most devastating death rate of gynecological cancers with only 44% of women surviving 5 years after diagnosis. Toll-like receptors (TLRs) signaling can play an important role in the OC treatment. TLR activation in immune cells can help activate an effective antitumor response. In this scenario, a new perspective is represented by combined OncoTherad (MRB-CFI-1) immunotherapy and Platelet Rich Plasma (PRP). OncoTherad (MRB-CFI-1) leads to the distinct stimulation of the innate immune system mediated by TLR2 and TLR4, resulting in an increased activation of the IFN signaling pathway. Also, PRP acts on immune activation and exerts antitumor effects. This study characterized the histopathological and molecular effects of the OncoTherad associated with PRP in the treatment of OC chemically induced in rats and described the possible mechanisms of action of this association involving the TLRs 2 and 4 signaling pathways. Methods: Fischer 344 female rats were divided into 5 groups (n = 7 animals per group): Control (Sham surgery) group; Cancer (7,12 dimethylbenzoanthracene – DMBA injection in the ovarian bursa, 1.25 mg/kg) group; OncoTherad (20mg/kg) group; PRP (328.103 – 549.103 platelets/mm3) group and; OncoTherad+PRP (same doses of the isolated treatments) group. Intraperitoneal doses were administered twice a week for 4 weeks. Immunohistochemistry was analyzed as total immunoreactivity and intensity of immunoreaction. Results: Our results showed serous type ovarian carcinoma, follicular atresia, absence of corpora lutea and hyperplasia of the germinal epithelium and tunica albuginea in the Cancer group. The histopathological changes in the PRP group were similar as Cancer group. In contrast, the animals treated with OncoTherad singly or in combination with PRP showed decrease of ovarian neoplastic lesions and histopathological recovery. TLR4 and IL-6 immunoreactivities were significantly lower (p &lt; 0.05) in the Cancer group. PRP treatment reduced (p &lt; 0.05) TLR2. In the Oncotherad+PRP group, the immunoreactivities of TLR4, MyD88, IRF-3 and TNF-α were lower. OncoTherad treatment alone led to stimulation of the innate immune system mediated by TLR2 and TLR4, resulting in an increased activation of the MyD88 signaling pathway (intensified IL-6 and TNF-α immunoreactivities). Conclusions: OncoTherad immunotherapy was able to reduce ovarian lesions and stimulated the TLR2 and 4 signaling pathways in the OC microenvironment, leading to antitumor effects by activating the production of inflammatory cytokines. Thus, OncoTherad immunotherapy could be considered an important therapeutic strategy for OC.

Lactoferrin averts neurological and behavioral impairments of thioacetamide-induced hepatic encephalopathy in rats via modulating HGMB1/TLR-4/MyD88/Nrf2 pathway

Hepatic encephalopathy (HE) is a life-threatening disease caused by acute or chronic liver failure manifested by aberrant CNS changes. In the present study, we aimed to explore the neuroprotective effect of lactoferrin (LF) against thioacetamide (TAA)-induced HE in rats. Animals were divided into four groups, control, LF control, TAA-induced HE, and LF treatment, where LF was administered (300 mg/kg, p.o.) for 15 days in groups 2 and 4 meanwhile, TAA (200 mg/kg, i.p.) was given as two injections on days 13 and 15 for the 3rd and 4th groups. Pretreatment with LF significantly improved liver function observed as a marked decline in serum AST, ALT, and ammonia, together with lowering brain ammonia and enhancing motor coordination as well as cognitive performance. Restoration of brain oxidative status was also noted in the LF-treated group, where lipid peroxidation was hampered, and antioxidant parameters, Nrf2, HO-1, and GSH, were increased. Additionally, LF downregulated HMGB1, TLR-4, MyD88, and NF-κB signaling pathways, together with reducing inflammatory cytokine, TNF-α, and enhancing brain BDNF levels. Moreover, the histopathology of brain and liver tissues revealed that LF alleviated TAA-induced liver and brain deficits. In conclusion, the promising results of LF in attenuating HMGB1/TLR-4/MyD88 signaling highlight its neuroprotective role against HE associated with acute liver injury via ameliorating neuroinflammation, oxidative stress, and stimulating neurogenesis.

Myd88 Signaling Is Involved in the Inflammatory Response in LPS-Induced Mouse Epididymitis and Bone-Marrow-Derived Dendritic Cells.

Epididymitis is an epididymal inflammation that may lead to male infertility. Dendritic cells (DCs) and myeloid differentiation primary response gene 88 (Myd88) were associated with epididymitis in rodents. However, the functions of Myd88 on epididymal DCs remain unclear. This study investigated the role of Myd88 in DCs for epididymitis. The Myd88 signaling pathway, phenotypes of DC subsets, and cytokines were investigated in lipopolysaccharide (LPS)-induced epididymitis in mice. CRISPR-Cas9 was used to knockout Myd88 in bone-marrow-derived dendritic cells (BMDCs) and immortalized mouse epididymal (DC2) cell line. In the vivo experiments, levels of the proinflammatory cytokines IL-1α, IL-6, IL-17A, TNF-α, IL-1β, MCP-1, and GM-CSF, mRNA for MyD88 related genes, and the percentages of monocyte-derived DCs (Mo-DCs) were significantly elevated in mice with epididymitis. In the vitro experiments, LPS significantly promoted the apoptosis of BMDCs. In addition, the concentration of inflammatory cytokines in BMDCs and DC2s were increased in the LPS group, while decreasing after the knockout of Myd88. These findings indicate that Myd88 on DCs is involved in the inflammation of epididymitis in mice, which may be a potential target for better strategies regarding the treatment of immunological male infertility.

Abstract 6410: Deciphering the role of MyD88 signaling pathway in regulating type I IFN-mediated responses to radiation therapy in solid tumors

Abstract The balance of innate signaling through adaptor proteins such as MyD88 and TRIF is critical in directing the pattern of inflammatory responses following exposure to endogenous adjuvants. While innate stimuli can cause inflammation that supports adaptive immunity, cancer myeloid cells can be pre-polarized such that the same inflammatory signals cause myeloid cells to suppress adaptive immune responses. We aim to investigate the signals regulating type I IFN secretion by innate immune cells in tumors in order to improve type I IFN secretion, activation of innate immune cells, direct macrophage polarization and improve CD8+ T cell mediated anti-tumor immunity. To better understand the role of MyD88-mediated signaling in driving response to innate adjuvants released following RT in solid tumors, we developed MyD88 conditional knockout mouse models. MyD88 was deleted specifically in CD11c expressing dendritic cells (DC), Lck expressing T cells, or Lyz2 expressing myeloid cells that include macrophages, monocytes and granulocytes. Mice bearing pancreatic tumors (Panc02-SIY or PK5L1940) were randomized to no treatment or 16 Gy CT-guided RT and followed for treatment responses. Lyz2-Cre/MyD88fl/fl mice demonstrated improved responses to RT in pancreatic tumors as compared to control MyD88fl/fl mice, or Lck-Cre mice. The improved responses in Lyz2-Cre/MyD88fl/fl mice were shown to be dependent on CD8+ T cells as well as on type I IFN signaling. To analyze mechanisms of response, tumors were digested into a single cell suspension and CD45+ cells were isolated for single cell sequencing three days post-RT. Lyz2-Cre/MyD88fl/fl mice showed diminished Th1 and Th2-type T cells and had a higher M1/TAM ratio compared to MyD88fl/fl mice. Loss of MyD88 in myeloid cells resulted in increased activation of IFN-dependent transcriptional responses in multiple immune cell populations in the tumor. To model responses ex vivo, bone marrow-derived macrophages (BMDMs) were activated with lipopolysaccharide (LPS) or a synthetic cyclic dinucleotide (CDA) for analysis of cytokine secretion in either monolayer or 3D spheroid culture conditions. BMDM derived from Lyz2-Cre/MyD88fl/fl cultured as a monolayer showed significantly altered secretion of TNF-α, IL-10 and IL-6 on activation with LPS as compared to controls. Preliminary data obtained from 3D spheroid culture systems demonstrated that 3D interactions between cancer cells and macrophages resulted in a significant increase in BMDM co-stimulatory phenotype following activation with innate stimuli compared to 2D cultures. These data suggest that conventional innate signaling through MyD88 in myeloid populations suppresses IFN production and adaptive immune control of irradiated tumors. 3D cultures are an effective tool to study cellular interactions ex vivo and screen novel interventions prior to in vivo translation. Citation Format: Aanchal Preet Kaur, Terry R. Medler, Tiffany C. Blair, Alejandro F. Alice, Megan R. Ball, Alexa K. Dowdell, Brian D. Piening, Marka R. Crittenden, Michael J. Gough. Deciphering the role of MyD88 signaling pathway in regulating type I IFN-mediated responses to radiation therapy in solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6410.

TLR4 agonist activity of Alcaligenes lipid a utilizes MyD88 and TRIF signaling pathways for efficient antigen presentation and T cell differentiation by dendritic cells.

Alcaligenes faecalis was previously identified as an intestinal lymphoid tissue-resident commensal bacteria, and our subsequent studies showed that lipopolysaccharide and its core active element (i.e., lipid A) have a potent adjuvant activity to promote preferentially antigen-specific Th17 response and antibody production. Here, we compared A. faecalis lipid A (ALA) with monophosphoryl lipid A, a licensed lipid A-based adjuvant, to elucidate the immunological mechanism underlying the adjuvant properties of ALA. Compared with monophosphoryl lipid A, ALA induced higher levels of MHC class II molecules and costimulatory CD40, CD80, and CD86 on dendritic cells (DCs), which in turn resulted in strong T cell activation. Moreover, ALA more effectively promoted the production of IL-6 and IL-23 from DCs than did monophosphoryl lipid A, thus leading to preferential induction of Th17 and Th1 cells. As underlying mechanisms, we found that the ALA-TLR4 axis stimulated both MyD88- and TRIF-mediated signaling pathways, whereas monophosphoryl lipid A was biased toward TRIF signaling. These findings revealed the effects of ALA on DCs and T cells and its induction pattern on signaling pathways.

A soluble TLR5 is involved in PBLs activation and antibacterial immunity via TLR5M-MyD88-signaling pathway in tongue sole Cynoglossus semilaevis

In higher vertebrates, there is only a membranal TLR5 (TLR5M), which is crucial for host defense against microbes via MyD88 signaling pathway. In teleost, both TLR5M and soluble TLR5 (TLR5S) are identified, whereas the antibacterial mechanism of TLR5S is largely unknown. In this study, we studied the immune antibacterial mechanism of Cynoglossus semilaevis TLR5S homologue (named CsTLR5S). CsTLR5S, a 71.1 kDa protein, consists of 649 amino acid residues and shares 41.7 %–57.8 % overall sequence identities with teleost TLR5S homologues. CsTLR5S contains a single extracellular domain (ECD) composed of 12 leucine-rich repeats. CsTLR5S expression was constitutively identified and upregulated by bacterial infection in tissues. In vitro recombinant CsTLR5S (rCsTLR5S) could interact with bacteria and tongue sole rTLR5M (rCsTLR5M). Furthermore, rCsTLR5S could bind to the membranal CsTLR5M of peripheral blood leukocytes (PBLs), which led to enhancing the activity and the antibacterial role of PBLs via Myd88-NF-κB pathway. In vivo rCsTLR5S could activate the Myd88-NF-κB pathway, facilitate the release of proinflammatory cytokines, and enhance the host antibacterial response against Vibrio harveyi. Moreover, the knockdown of CsTLR5M or the Myd88 inhibitor could significantly suppress the antibacterial effect of rCsTLR5S. Collectively, our findings added important insights into the TLR5S immune antibacterial property in a TLR5M-MyD88-dependent manner.

Effects of the Co-Administration of Morphine and Lipopolysaccharide on Toll-Like Receptor-4/Nuclear Factor Kappa β Signaling Pathway of MDA-MB-231 Breast Cancer Cells.

The Toll-like receptor 4 (TLR4) gene promotes migration in adenocarcinoma cells. Morphine is an agonist for TLR4 that has a dual role in cancer development. The promoter or inhibitor role of morphine in cancer progression remains controversial. This study aims to evaluate the effects of morphine on the TLR4, myeloid differentiation primary response protein 88-dependent (MyD88), and nuclear factor-kappa B (NF-κB) expressions in the human MDA-MB-231 breast cancer cell line. The cells were examined after 24 hours of incubation with morphine using the Boyden chamber system. TLR4, MyD88, and NF-κB mRNA expressions were assessed using quantitative real-time polymerase chain reaction (RT-PCR). The concentration of interleukin-2 beta was also measured using the ELISA assay. According to the findings, three doses of morphine (0.25, 1.25, and 0.025 μM) increased the expression of the TLR4 and NF-κB genes, whereas no significant change was observed in the mRNA expression of MyD88. Furthermore, treatment with morphine and lipopolysaccharide (LPS) significantly decreased the expression of TLR4, MyD88, and NF-κB. However, no significant change was observed in interleukin 2 beta concentration. These findings confirmed the excitatory effects of morphine on TRL4 expression and the MYD88 signaling pathway in vitro.

Anti-glycation and anti-inflammatory activities of anthocyanins from purple vegetables.

Anthocyanins may be effective bioactive constituents to reduce the potential risk of chronic diseases induced by glycation and inflammation. In the present study, the anti-glycation and anti-inflammatory activities of anthocyanins derived from purple cabbage (PCA), purple sweet potato (PSP), purple corn (PCO) and gynura bicolor (GB) were evaluated. According to the results from the bovine serum albumin (BSA)-fructose and BSA-methylglyoxal (MGO) model, the inhibition effects of anthocyanins on non-enzymatic glycosylation not only acted on the intermediate stage, but also played a certain role in the entire non-enzymatic glycosylation process, among which anthocyanins from PCA exhibited the best inhibitory effect. The anthocyanins from all four purple vegetables could trap MGO effectively (p > 0.05). The anthocyanins also presented a good inhibitory effect on amyloid beta peptide (Aβ)1-42 fibrillation, even better than that of aminoguanidine (AG), in a thermal induction assay. Furthermore, anthocyanins from PCA, PSP, PCO and GB showed significant anti-inflammatory effects, inhibiting pro-inflammatory factor (i.e., NO and TNF-α) production, among which the anthocyanins from PCA and PSP exhibited a higher inhibition effect than the others. This is probably due to the suppression of the TLR4-mediated MyD88 signaling pathway in the lipopolysaccharide (LPS)-induced BV2 cells based on the western blot analysis. Anthocyanins from purple vegetables could be used as a value-added food ingredient for the food industry. Food fortification with anthocyanins might be a promising way to protect humans against various chronic diseases caused by glycation and inflammation.

Effect of epithelial-specific MyD88 signaling pathway on airway inflammatory response to organic dust exposure

The Toll-like receptor (TLR) adaptor protein MyD88 is integral to airway inflammatory response to microbial-enriched organic dust extract (ODE) exposures. ODE-induced airway neutrophil influx and release of pro-inflammatory cytokines was essentially abrogated in global MyD88-deficient mice, yet these mice demonstrate an increase in airway epithelial cell mucin expression. To further elucidate the role of MyD88-dependent responses specific to lung airway epithelial cells in response to ODE in vivo, the surfactant protein C protein (SPC) Cre+ embryologic expressing airway epithelial cells floxed for MyD88 to disrupt MyD88 signaling were utilized. The inducible club cell secretory protein (CCSP) Cre+, MyD88 floxed, were also developed. Using an established protocol, mice were intranasally instilled with ODE or saline once or daily up to 3 weeks. Mice with MyD88-deficient SPC+ lung epithelial cells exhibited decreased neutrophil influx following ODE exposure once and repetitively for 1 week without modulation of classic pro-inflammatory mediators including tumor necrosis factor (TNF)-α, interleukin (IL)-6, and neutrophil chemoattractants. This protective response was lost after 3 weeks of repetitive exposure. ODE-induced Muc5ac mucin expression at 1 week was also reduced in MyD88-deficient SPC+ cells. Acute ODE-induced IL-33 was reduced in MyD88-deficient SPC+ cells whereas serum IgE levels were increased at one week. In contrast, mice with inducible MyD88-deficient CCSP+ airway epithelial cells demonstrated no significant difference in experimental indices following ODE exposure. Collectively, these findings suggest that MyD88-dependent signaling targeted to all airway epithelial cells plays an important role in mediating neutrophil influx and mucin production in response to acute organic dust exposures.