Acupuncture Ameliorates Depression-Like Behaviors Through Modulating the Neuroinflammation Mediated by TLR4 Signaling Pathway in Rats Exposed to Chronic Restraint Stress

Recently, emerging evidence has identified that stress-induced activation of neuroinflammation is considered to be one of the most prevalently precipitating factors in the pathogenesis of depression. Data from clinical trials and experimental findings has verified the efficacy and safety of acupuncture in the prevention and treatment of depression. However, the mechanism of the preventive effect of acupuncture for depression has not been fully elucidated. The current study aimed to investigate the preventive effect and mechanism of acupuncture through modulating the neuroinflammation mediated by toll-like receptor 4 (TLR4) signaling pathway in rats exposed to chronic restraint stress (CRS). All rats were subjected to CRS for 21 days, with the exception of rats in control group. One hour before CRS, rats in acupuncture group were exposed to acupuncture at Baihui (GV20) and Yintang (GV29). The depression-like behaviors were evaluated by body weight assessment and sucrose preference test at 0, 7, 14, and 21 days. The expression of activated microglia in hippocampus was detected by immunofluorescence. The expression of key proteins on TLR4 signaling pathway of TLR4, MyD88, TRAF6, NF-κB p65, TNF-α, and mRNA of TLR4 in the hippocampus was detected by western blot and real-time quantitative polymerase chain reaction to investigate the effect of acupuncture on stress-induced activation of neuroinflammation. The present study provided evidence that acupuncture exerted potential preventive effect that might be mediated in part by suppressing the neuroinflammation induced by TLR4 signaling pathway, which may be a promising treatment target to improve current treatments for depression.

Inhibition of TLR4/NF-κB pathway and endoplasmic reticulum stress by overexpressed S100A4 ameliorates retinal ischemia-reperfusion injury of mice

Retinal ischemia exists in various ischemic retinopathies including glaucoma, contributing to the death of retinal neurons. Calcium binding protein S100A4 is important in tumors, and our previous study found that S100A4 protects retinal ganglion cells (RGCs) against retinal ischemia-reperfusion (I/R) injury. This study was aimed to further discuss the neuroprotection and mechanisms of S100A4 in retinal I/R of mice. The rAAV-EF1α-s100a4-EGFP-WPRE or rAAV-EF1α-EGFP-WPRE-Pa was injected intravitreally 4 weeks before I/R. S100A4, molecules in TLR4 signaling pathway and endoplasmic reticulum (ER) stress branches, inflammatory molecules, and surviving RGCs and cholinergic amacrine (ChAT) cells were determined by quantitative PCR, western blot, or immunofluorescent staining. The apoptosis and necrosis of retinal neurons induced by I/R were inhibited by overexpressed S100A4. RGCs, ChAT cells, and the retinal function were preserved by S100A4 overexpressing 7 days after I/R. Mechanistically, the beneficial effects of S100A4 may be mediated by inhibiting the activation of TLR4 signaling pathway and alleviating ER stress, leading to the attenuation of inflammatory response of the retina after I/R. Our findings indicated that S100A4 has neuroprotective effect against retinal I/R injury, and promoting S100A4 expression may be an effective strategy to inhibit retinal neurons from degeneration in ischemic retinopathy.

IgA nephropathy: gut microbiome regulates the production of hypoglycosilated IgA1via the TLR4 signaling pathway

BACKGROUND

IgA nephropathy (IgAN) is a major cause of primary glomerulonephritis characterized by mesangial deposits of galactose-deficient IgA1 (Gd-IgA1). Toll-like receptors (TLRs), particularly TLR4 are involved in the pathogenesis of IgAN. The role of gut microbiota on IgAN patients was recently investigated. However, whether gut microbial modifications of Gd-IgA1 through TLR4 play a role in IgAN remains unclear.

METHODS

We recruited subjects into four groups, including 48 patients with untreated IgAN, 22 treated IgAN patients (IgANIT), 22 primary membranous nephropathy (MN), and 31 healthy controls (HCs). Fecal samples were collected to analyze changes in gut microbiome. Gd-IgA1 levels, expression of TLR4, B-cell stimulators, and intestinal barrier function were evaluated in all subjects. C57BL/6 mice were treated with a broad-spectrum antibiotic cocktail to deplete the gut microbiota and then gavaged with fecal microbiota transplanted fromclinical subjects of every group. Gd-IgA1 and TLR4 pathway were detected in peripheral blood mononuclear cells (PBMCs) from IgAN and HCs co-incubated with Lipopolysaccharide (LPS) and TLR4 inhibitor.

RESULTS

Compared with other three groups, different compositions and decreased diversity demonstrated gut dysbiosis in un-treated IgAN, especially the enrichment of Escherichia -Shigella. Elevated Gd-IgA1 levels were found in un-treated IgAN patients and correlated with gut dysbiosis, TLR4, B-cell stimulators, indexes of intestinal barrier damage, and proinflammatory cytokines. In vivo, mice colonized with gut microbiota from IgAN and IgANIT patients, copied the IgAN phenotype with the activation of TLR4/MyD88/NF-κB pathway, B-cell stimulators in the intestine, and complied with enhanced proinflammatory cytokines. In vitro, LPS activated TLR4/MyD88/NF-κB pathway, B-cell stimulators and proinflammatory cytokines in the PBMCs from IgAN patients, which resulted in overproduction of Gd-IgA1 and inhibited by TLR4 inhibitor.

CONCLUSIONS

Our results illustrated that gut-kidney axis was involved in the pathogenesis of IgAN. Gut dysbiosis could stimulate the overproduction of Gd-IgA1 by TLR4 signaling pathway production and B-cell stimulators.

The PTX3/TLR4 autocrine loop as a novel therapeutic target in triple negative breast cancer

BACKGROUND

The pattern recognition receptor long pentraxin-3 (PTX3) plays conflicting roles in cancer by acting as an oncosuppressor or as a pro-tumor mediator depending on tumor context. Triple negative breast cancer (TNBC) represents the most aggressive histotype of breast cancer, characterized by the lack of efficacious therapeutic targets/approaches and poor prognosis. Thus, the characterization of new molecular pathways and/or alternative druggable targets is of great interest in TNBC.

METHODS

The expression of PTX3 in BC tumor samples and in BC cell lines has been analyzed using the Gene Expression-Based Outcome for Breast Cancer Online (GOBO), qPCR, Western blot and ELISA assay. The contribution of tumor and stromal cells to PTX3 production in TNBC was assessed by analyzing single cell RNA sequencing data and RNAscope performed on TNBC tumor samples. In order to investigate the effects of PTX3 in TNBC, different cell lines were engineered to knock-down (MDA-MB-231 and BT549 cells) or overexpress (MDA-MB-468 and E0771 cells) PTX3. Finally, using these engineered cells, in vitro (including gene expression profiling and gene set enrichment analyses) and in vivo (orthotopic tumor models in immune-compromised and immune competent mice) analyses were performed to assess the role and the molecular mechanism(s) exerted by PTX3 in TNBC.

RESULTS

In silico and experimental data indicate that PTX3 is mainly produced by tumor cells in TNBC and that its expression levels correlate with tumor stage. Accordingly, gene expression and in vitro results demonstrate that PTX3 overexpression confers a high aggressive/proliferative phenotype and fosters stem-like features in TNBC cells. Also, PTX3 expression induces a more tumorigenic potential when TNBC cells are grafted orthotopically in vivo. Conversely, PTX3 downregulation results in a less aggressive behavior of TNBC cells. Mechanistically, our data reveal that PTX3 drives the activation of the pro-tumorigenic Toll-like receptor 4 (TLR4) signaling pathway in TNBC, demonstrating for the first time that the PTX3/TLR4 autocrine stimulation loop contributes to TNBC aggressiveness and that TLR4 inhibition significantly impacts the growth of PTX3-producing TNBC cells.

CONCLUSION

Altogether, these data shed light on the role of tumor-produced PTX3 in TNBC and uncover the importance of the PTX3/TLR4 axis for therapeutic and prognostic exploitation in TNBC.

Dietary Bacillus velezensis R-71003 and sodium gluconate improve antioxidant capacity, immune response and resistance against Aeromonas hydrophila in common carp

This study aimed to evaluate the effects of dietary supplementation with Bacillus velezensis R-71003 combined with sodium gluconate on antioxidant capacity, immune response and resistance against Aeromonas hydrophila in common carp. In addition, the biocontrol potential of the secondary metabolites of B. velezensis R-71003 was also evaluated to analyze the possible mechanism of B. velezensis R-71003 against A. hydrophila. The results indicated that the antibacterial crude extract of B. velezensis R-71003 can destroy the cell wall of A. hydrophila. Moreover, the results showed that dietary B. velezensis R-71003 could promote antioxidant capacity, which significantly increased the activities of CAT and SOD and decreased the content of MDA. Additionally, B. velezensis R-71003 supplementation significantly enhanced the immunity of common carp, as measured by the mRNA expression levels of cytokine-related genes (TNF-α, TGF-β, IL-1β and IL-10). In addition, dietary B. velezensis R-71003 exhibited an upregulation of IL-10 and a downregulation of IL-1β, coupled with higher survival rates when challenged with A. hydrophila compared to the positive group. Furthermore, compared to prechallenge, the mRNA expression levels of TLR-4, MyD88, IRAK1, TRAF6, TRIF and NF-κB in the head kidney of common carp were significantly increased after challenge. The fish fed the B. velezensis R-71003 diet showed lower expression of TLR-4, MyD88, IRAK1, TRAF6, TRIF and NF-κB after the challenge than those fed the control diet. Thus, this study revealed that B. velezensis R-71003 can improve the resistance of common carp to pathogenic bacteria by destroying bacterial cell walls and improving fish immunity by activating the TLR4 signaling pathway. Importantly, this study indicated that sodium gluconate has a positive effect on B. velezensis R-71003 in enhancing the anti-infection ability of common carp. The results of this study will lay the foundation for the application of B. velezensis R-71003 in combination with sodium gluconate as an alternative to antibiotics in aquaculture.

ITGB4 deficiency in airway epithelia enhances HDM-induced airway inflammation through hyperactivation of TLR4 signaling pathway

Airway epithelial cells (AECs) are the first cell barrier of the respiratory system against external stimuli that play a critical role in the development of asthma. It is known that AECs play a key role in asthma susceptibility and severity. ITGB4 is a downregulated adhesion molecule in the airway epithelia of asthma patients, which was involved in the exaggerated lung inflammation after allergy stimulation. Toll-like receptor 4 (TLR4) in AECs has also been shown to play a crucial role in the development of lung inflammation in asthma patients. However, the specific intrinsic regulatory mechanism of TLR4 in AECs are still obscure. In this article, we demonstrated that ITGB4 deficiency in AECs enhances HDM-induced airway inflammation through hyperactivation of the TLR4 signaling pathway, which is mediated by inhibition of FYN phosphorylation. Moreover, TLR4-antagonist treatment or blockade of FYN can inhibit or exaggerate lung inflammation in HDM-stressed ITGB4-deficient mice, separately. Together, these results demonstrated that ITGB4 deficiency in AECs enhances HDM-induced lung inflammatory response through the ITGB4-FYN-TLR4 axis, which may provide new therapeutic approaches for the management of lung inflammation in asthma.

Gut microbiota dysbiosis exaggerates ammonia-induced tracheal injury Via TLR4 signaling pathway

Ammonia is a toxic air pollutant that causes severe respiratory tract injury in animals and humans. Gut microbiota dysbiosis has been found to be involved in the development of respiratory tract injury induced by air pollutants, however, the specific mechanism requires investigation. Here, we found that, inhaled ammonia induced tracheal injury by reducing expression of claudin-1, increasing expression of muc5ac, TLR4, MyD88, NF-κB and cytokines (TNF-α, IL-1β, IL-6 and IL-10), and also altering tracheal microbiota composition. Spearman correlation analysis indicated that gut microbiota dysbiosis positively correlated with TLR4 level in the trachea. Antibiotic depletion intestinal microbiota treatment reduced the severity of ammonia-induced tracheal injury via TLR4 signaling pathway. Microbiota transplantation induced the tracheal injury via TLR4 signaling pathway even without the ammonia exposure. These results indicate that gut microbiota dysbiosis exaggerates ammonia-induced tracheal injury via TLR4 signaling pathway. In addition, the [Ruminococcus]_torques_group, Faecalibacterium, unclassified_f_Lachnospiraceae may be the key gut microbiota contributing to the alterations of tracheal microbiota composition.

KIF26B-AS1 Regulates TLR4 and Activates the TLR4 Signaling Pathway to Promote Malignant Progression of Laryngeal Cancer

Laryngeal cancer is one of the highest incidence, most prevalently diagnosed head and neck cancers, making it critically necessary to probe effective targets for laryngeal cancer treatment. Here, real-time quantitative reverse transcription PCR (qRT-PCR) and western blot analysis were used to detect gene expression levels in laryngeal cancer cell lines. Fluorescence in situ hybridization (FISH) and subcellular fractionation assays were used to detect the subcellular location. Functional assays encompassing Cell Counting Kit-8 (CCK-8), 5-ethynyl-2'-deoxyuridine (EdU), transwell and wound healing assays were performed to examine the effects of target genes on cell proliferation and migration in laryngeal cancer. The in vivo effects were proved by animal experiments. RNA-binding protein immunoprecipitation (RIP), RNA pulldown and luciferase reporter assays were used to investigate the underlying regulatory mechanisms. The results showed that KIF26B antisense RNA 1 (KIF26B-AS1) propels cell proliferation and migration in laryngeal cancer and regulates the toll-like receptor 4 (TLR4) signaling pathway. KIF26B-AS1 also recruits FUS to stabilize TLR4 mRNA, consequently activating the TLR4 signaling pathway. Furthermore, KIF26B-AS1 plays an oncogenic role in laryngeal cancer via upregulating TLR4 expression as well as the FUS/TLR4 pathway axis, findings which offer novel insight for targeted therapies in the treatment of laryngeal cancer patients.

The Role of Microglia/Macrophages Activation and TLR4/NF-κB/MAPK Pathway in Distraction Spinal Cord Injury-Induced Inflammation

Distraction spinal cord injuries (DSCIs) often occur as the neurological complication of distraction forces following the implantation of internal fixation devices during scoliosis correction surgery. However, the underlying mechanism behind these injuries remains unclear. The present study aimed to explore the activation of microglia and macrophages, as well as changes in TLR4-mediated NF-κB and MAPK pathway activity after DSCIs in Bama miniature pigs. Prior to surgical intervention, the pigs were randomly divided into three groups: the sham group, the complete distraction spinal cord injury (CDSCI) group, and the incomplete distraction spinal cord injury (IDSCI) group. After surgery, the Tarlov scale and individual limb motor scale (ILMS) were used to evaluate changes in the pigs’ behavior. All pigs were euthanized 7 days after surgery, and histopathological examinations of the spinal cord tissues were performed. Immunohistochemistry was used to detect Caspase-3 expression in the anterior horn of spinal gray matter tissues. Immunofluorescence staining was utilized to assess the M1/M2 phenotype changes in microglia/macrophages and NF-κB P65 expression in central DSCI lesions, while western blotting was performed to determine the expression of TLR4/NF-κB/MAPK pathway-related proteins. The results of the present study showed that the Tarlov and ILMS scores decreased significantly in the two DSCI groups compared with the sham group. Hematoxylin and eosin (HE) and Nissl staining revealed that the tissue structure and nerve fiber tracts in the distracted spinal cord tissues were destroyed. Both DSCI groups showed the number of survived neurons decreased and the Caspase-3 expression increased. The results of the immunofluorescence staining indicated that the CD16 and CD206 expression in the microglia/macrophages increased. Between the two DSCI groups, the CDSCI group showed increased CD16 and decreased CD206 expression levels. The intensity of the fluorescence of NF-κB P65 was found to be significantly enhanced in pigs with DSCIs. Moreover, western blot results revealed that the expression of TLR4, p-IκBα, NF-κB P65, p-JNK, p-ERK, and p-P38 proteins increased in spinal cord tissues following DSCI. The present study was based on a porcine DSCI model that closely mimicked clinical DSCIs while clarifying DSCI-associated neuroinflammation mechanisms, in turn providing evidence for identifying potential anti-inflammatory targets.

Dangshen Erling Decoction Ameliorates Myocardial Hypertrophy via Inhibiting Myocardial Inflammation

Myocardial hypertrophy plays an essential role in the structural remodeling of the heart and the progression to heart failure (HF). There is an urgent need to understand the mechanisms underlying cardiac hypertrophy and to develop treatments for early intervention. Dangshen Erling decoction (DSELD) is a clinically used formula in Chinese medicine for treating coronary heart disease in patients with HF. However, the mechanism by which DSELD produces its cardioprotective effects remains largely unknown. This study explored the effects of DSELD on myocardial hypotrophy both in vitro and in vivo. In vitro studies indicated that DSELD significantly (p < 0.05) reduced the cross-sectional area of the myocardium and reduced elevated lactate dehydrogenase (LDH), tumor necrosis factor (TNF)-α, and interleukin (IL)-6 levels in the induced H9C2 cell model to study inflammation. In vivo experiments revealed that DSELD restores cardiac function and significantly reduces myocardial fibrosis in isoproterenol (ISO)-induced HF mouse model (p < 0.05). In addition, DSELD downregulated the expression of several inflammatory cytokines, such as granulocyte-macrophage colony-stimulating factor (GM-CSF), granulocyte CSF (G-CSF), IL-1α, IL-1β, IL-3, IL-5, IL-7, IL-12, IL-13, and TNF-α in HF (p < 0.05). Further analysis of the cardiac tissue demonstrated that DSELD produces its anti-inflammatory effects via the Toll-like receptor (TLR)4 signaling pathway. The expression of TLR4 downstream proteins such as matrix metalloproteinase-9 (MMP9) and myeloid differentiation factor-88 (MyD88) was among the regulated targets. In conclusion, these observations suggest that DSELD exerts antihypertrophic effects by alleviating the inflammatory injury via the TLR4 signaling pathway in HF and thus holds promising therapeutic potentials.

Early continuous blood purification affects TNF-α, IL-1β, and IL-6 in patients with severe acute pancreatitis via inhibiting TLR4 signaling pathway

To exploit whether early continuous blood purification (CBP) inhibits the Toll-like receptors 4 (TLR4) signaling pathway in the peripheral blood of patients with severe acute pancreatitis (SAP) and whether it affects the abundance of inflammatory factors; 130 SAP patients were randomly selected and divided into Groups B and C. Both groups received conventional treatment. Among them, Group C was given early CBP treatment. Another 60 healthy cases in physical examination at the same time were selected as Group A. The abundances of TLR4 and inflammatory factors were detected before and after treatment. Compared with Group B, (1) the symptoms in Group C improved more markedly; (2) protein contents of TLR4 and nuclear factor kappa B (NF-κB) in Group C diminished more signally; (3) the abundances of tumor necrosis factor alpha (TNF-α), cytokine interleukin-1β (IL-1β), and cytokine interleukin 6 (IL-6) in Group C decreased (p < 0.05); and (4) the abundance of TLR4 in Group C was positively correlated with those of TNF-α, IL-1β, and IL-6 after treatment (all p < 0.001). Early CBP inhibits TLR4 signaling pathway in SAP patients and attenuates the abundance of inflammatory factors to a certain extent, which may provide a new clinical treatment strategy for SAP.

Protective effect of sinomenine against inflammation and oxidative stress in gestational diabetes mellitus in female rats via TLR4/MyD88/NF-κB signaling pathway

Gestational diabetes mellitus (GDM) is a dangerous complication of pregnancy which is induced via dysfunction in glucose metabolism during pregnancy. Sinomenine (SM) has already proved an antidiabetic effect against streptozotocin (STZ)-induced diabetes mellitus (DM) in rats. In this protocol, we examined the protective effect of SM against STZ-induced GDM in rats. Wistar rats were divided into three groups and STZ (40 mg/kg) was used to induce GDM. At the end of the experimental protocol, bodyweight, pub weight, and survival rate were estimated. Blood glucose level (BGL), fasting insulin (FINS), free fatty acid (FFA), Hemoglobin A1C (HbA1c), and C-peptide were measured. Lipid, antioxidant, inflammatory cytokines, and inflammatory mediators were also determined. RT-PCR was used for estimation of the role of TLR4/MyD88/NF-κB signaling pathway. SM treatment significantly (p < .001) reduced BGL, hepatic glycogen, and improved the levels of FINS, C-peptide, FFA, and HbA1c. SM significantly (p < .001) suppressed the levels of total cholesterol (TC), low-density lipoprotein (LDL), triglycerides (TG), coronary artery index (CAI), very low-density lipoprotein (VLDL), atherogenic index (AI), and boosted high-density lipoprotein (HDL) levels. SM significantly (p < .001) decreased the lipid peroxidation (LPO) level and enhanced glutathione peroxidase (GPx), total antioxidant capacity (TAC), glutathione S-transferase (GST), superoxide dismutase (SOD), respectively. It reduced the levels of inflammatory cytokines including interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and inflammatory mediators viz., nuclear kappa B factors (NF-κB). SM significantly (p < .001) reduced the mRNA expression of Myd88, NLRP3, TLR4, and NF-κB, which were boosted in the GDM group rats. These findings suggest that SM could be a probable drug to be used for treating GDM via inhibition of the TLR4 signaling pathway. PRACTICAL APPLICATIONS: It is well known that gestational diabetes mellitus (GDM) is a dangerous health problem during the pregnancy. SM reduced the glucose level; boosted the level of fasting insulin (FINS) and bodyweight. SM significantly improved the number of pubs and their survival rates. SM suppressed oxidative stress and inflammation via activation of TLR4/MyD88/NF-κB signaling pathway. According to our research, SM can be used as a preventive drug in the treatment of GDM during pregnancy.

The Anti-Inflammatory Properties of Phytochemicals and Their Effects on Epigenetic Mechanisms Involved in TLR4/NF-κB-Mediated Inflammation

Innate immune response induces positive inflammatory transducers and regulators in order to attack pathogens, while simultaneously negative signaling regulators are transcribed to maintain innate immune homeostasis and to avoid persistent inflammatory immune responses. The gene expression of many of these regulators is controlled by different epigenetic modifications. The remarkable impact of epigenetic changes in inducing or suppressing inflammatory signaling is being increasingly recognized. Several studies have highlighted the interplay of histone modification, DNA methylation, and post-transcriptional miRNA-mediated modifications in inflammatory diseases, and inflammation-mediated tumorigenesis. Targeting these epigenetic alterations affords the opportunity of attenuating different inflammatory dysregulations. In this regard, many studies have identified the significant anti-inflammatory properties of distinct naturally-derived phytochemicals, and revealed their regulatory capacity. In the current review, we demonstrate the signaling cascade during the immune response and the epigenetic modifications that take place during inflammation. Moreover, we also provide an updated overview of phytochemicals that target these mechanisms in macrophages and other experimental models, and go on to illustrate the effects of these phytochemicals in regulating epigenetic mechanisms and attenuating aberrant inflammation.

Trichlorocarban induces developmental and immune toxicity to zebrafish (Danio rerio) by targeting TLR4/MyD88/NF-κB signaling pathway

Trichlorocarban (TCC) is ubiquitously detected in environmental matrices, while there is a paucity of information regarding its systemic toxicity. In the present study, we observed that TCC exposure led to high embryo mortality, delayed hatching and yolk absorption, as well as increased malformations, such as closure of swim sac and yolk sac edema. Meanwhile, TCC affected the formation and branch of subintestinal veins (SIVs), intersegmental vessels and posterior cardinal veins. Especially, the SIVs were shrunk, and their branches were reduced or even broken along with reduced coverage area. TCC-induced oxidative stress and excessive apoptosis resulted from abnormal expression of the anti/pro-apoptotic genes. Significant reduction in the number and aggregation function of immune cells proved that TCC had prominent immunotoxicity to zebrafish. TCC-targeted TLR4 signaling pathway was demonstrated by abnormal expression of the marker genes (tlr4, MyD88 and nf-κb) and release of the downstream inflammatory factors (TNF-α, IL-6, etc.). Inhibition of TLR4/MyD88/NF-κB pathway by an inhibitor (CA-4948) rescued the decreasing trend of the immune cells induced by TCC. Molecular docking results demonstrated that TCC could stably bind to TLR4 receptor to form hydrogen bonds and hydrophobic interactions with amino acids. Overall, these findings reveal the underlying molecular mechanisms on TCC-induced developmental and immune toxicity to zebrafish.

MicroRNA-16 directly binds to DEC2 and inactivates the TLR4 signaling pathway to inhibit lupus nephritis-induced kidney tissue hyperplasia and mesangial cell proliferation

Lupus nephritis (LN) is the most serious manifestation of systemic lupus erythematosus (SLE) and a major risk of mortality. This research focused on the function of microRNA-16 (miR-16) in LN development. Fcgamma receptor II-b-deficient (Fcgr2b^-/-) mice with the natural potential to develop SLE- and LN-like diseases were used. Gain- and loss-of-function studies were performed to explore the function of miR-16 in pathological symptoms in mouse kidney tissues and the proliferation of mesangial cells (SV40 MES-13). The putative downstream molecules of miR-16 were explored. Consequently, poor expression of miR-16 was found in kidney tissues. Upregulation of miR-16 inhibited tissue hyperplasia, inflammatory infiltration, glomerular injury and fibrosis but increased cell apoptosis in mouse kidney tissues, and it inhibited proliferation but promoted apoptosis of MES-13 cells as well. miR-16 directly bound to DEC2 and inactivated the TLR4 signaling. DEC2 blocked the protective roles of miR-16 in MES-13 cells. The enhanced proliferation in MES-13 cells following miR-16 inhibition was reversed by chloroquine phosphate, a TLR4 antagonist. To sum up, miR-16 was evidenced to have a potent protective capacity in LN through relieving the LN symptoms in kidney tissues and reducing proliferation of mesangial cells, during which DEC2 silencing and TLR4 signaling deficit were involved.

microRNA-499-3p inhibits proliferation and promotes apoptosis of retinal cells in diabetic retinopathy through activation of the TLR4 signaling pathway by targeting IFNA2

microRNAs (miRNAs) are involved in the physiological and pathophysiological processes of diabetes and its microvascular and macrovascular complications. Hence, the aim of the study was to investigate whether miR-499-3p played an important role in diabetic retinopathy. Diabetic retinopathy was developed in rats by intraperitoneal injection of streptozocin (STZ), followed by collection of retinal tissues and preparation of retinal cells. Immunohistochemical staining was used to detect expression of interferon alpha 2 (IFNA2). RT-qPCR was used to determine the expression of miR-499-3p. Bioinformatics website and dual luciferase reporter gene assay were used to validate the targeting relationship between miR-499-3p and IFNA2. Gain- and loss-of-function assays were performed to explore the functional roles of aberrantly expressed miR-499-3p and IFNA2 in retinal cell proliferation by MTT, and apoptosis by flow cytometry. In retinal tissues and cells of diabetic rats, IFNA2 expression was reduced, and miR-499-3p expression increased to activate the toll-like receptor 4 (TLR4) signaling pathway. IFNA2 was a target gene of miR-499-3p and negatively regulated by miR-499-3p. Further, downregulated miR-499-3p promoted retinal cell proliferation while suppressing apoptosis to alleviate diabetic retinopathy. All in all, miR-499-3p promoted retinopathy by enhancing activation of the TLR4 signaling pathway, which provides a new therapeutic target for diabetic retinopathy.

Green tea polyphenols decrease weight gain, ameliorate alteration of gut microbiota, and mitigate intestinal inflammation in canines with high-fat-diet-induced obesity

Green tea polyphenols (GTPs) exhibit beneficial effects towards obesity and intestinal inflammation; however, the mechanisms and association with gut microbiota are unclear. We examined the role of the gut microbiota of GTPs treatment for obesity and inflammation. Canines were fed either a normal diet or high-fat diet with low (0.48% g/kg), medium (0.96% g/kg), or high (1.92% g/kg), doses of GTPs for 18 weeks. GTPs decreased the relative abundance of Bacteroidetes and Fusobacteria and increased the relative abundance of Firmicutes as revealed by 16S rRNA gene sequencing analysis. The relative proportion of Acidaminococcus, Anaerobiospirillum, Anaerovibrio, Bacteroides, Blautia, Catenibactetium, Citrobacter, Clostridium, Collinsella, and Escherichia were significantly associated with GTPs-induced weight loss. GTPs significantly (P<.01) decreased expression levels of inflammatory cytokines, including TNF-α, IL-6, and IL-1β, and inhibited induction of the TLR4 signaling pathway compared with high-fat diet. We show that the therapeutic effects of GTPs correspond with changes in gut microbiota and intestinal inflammation, which may be related to the anti-inflammatory and anti-obesity mechanisms of GTPs.

Protopine Protects Mice against LPS-Induced Acute Kidney Injury by Inhibiting Apoptosis and Inflammation via the TLR4 Signaling Pathway

Corydalis humosa Migo is a traditional Chinese medicine that clears away damp heat, relieves sore. Protopine (PRO) is an alkaloid component isolated from C. humosa Migo. However, the role of protopine in acute kidney injury (AKI) has not yet been reported. This study aims to investigate the effect and mechanism of protopine isolated from C. humosa Migo on lipopolysaccharide (LPS)-induced AKI in mice. Inflammation accumulation was assessed by small animal living imaging. The blood urea nitrogen (BUN), and serum creatinine (Scr) were measured to assess the effects of protopine on renal function in LPS-induced AKI. The levels of tumor necrosis factor (TNF), interleukin-2 (IL-2), interferon-γ (IFN-γ), and (interleukin-10) IL-10 in serum were detected by cytometric bead array. Flow cytometry was used to detect the levels of reactive oxygen species (ROS) in primary kidney cells. The proportions of granulocytes, neutrophils, and macrophages in peripheral blood were examined to evaluate the effect of protopine on immune cells in mice with AKI. Toll-like receptor (TLR4) and apoptotic signaling pathway were detected by Western blot analysis. The results showed that protopine markedly improved the renal function, relieve inflammation, reversed inflammatory cytokines, transformed apoptosis markers, and regulated the TLR4 signaling pathway in mice with AKI induced by LPS. The protopine isolated from C.humosa Migo protected mice against LPS-induced AKI by inhibiting apoptosis and inflammation via the TLR4 signaling pathway, thus providing a molecular basis for a novel medical treatment of AKI.

P-mapa, a promisor immunomodulator against tumor cells of colonic tissues: An investigation of the action mechanism over the TLR4 signaling pathway

Colorectal cancer (CRC) is a multifactorial syndrome that drives to uncontrollable cell division, genetic alterations, and functional alteration. In the present work, we evaluated the immunomodulatory properties of P-mapa, a compound extracted from Aspergillus oryzae fungus, versus Fluorouracil (5-FU) treatment in chemically induced CRC. CRC was induced by DMH in F344 rats. Animals of treated groups receive weekly 15 mg/Kg of 5-FU or 5 mg/Kg of P-mapa, over 10 weeks. Tissues were stained for aberrant crypt foci (ACF) counting and histopathology evaluation, immunostained for TLR4 pathways and quantified for TNFα Cytokine assay. DMH was efficient to induce hyperplastic lesions and ACF. Both treatments reduced significantly ACF formation and tumor aggressiveness. Immunohistochemistry for TLR4 signaling reveals that both treatments had no effect over the TLR4-NFκB signaling pathway. On the other hand, both succeed in increase interferon signaling, with activation of the TRIF-IRF3 pathway and consequently inducing IFNγ synthesis. The present results show the immunomodulatory properties of P-mapa in chemically induced CRC model. P-mapa induced a significant increase in Type-I IFNs synthesis and subsequently immune cell recruitment, resulting in an increase of IFNγ concentration in colorectal mucosa and its inhibitory effects over tumoral growth. In this scenario, P-mapa showed an interesting antitumoral effect by inhibiting tumor growth.

Effects of Fungal Polysaccharide on Oxidative Damage and TLR4 Pathway to the Central Immune Organs in Cadmium Intoxication in Chickens

Cadmium (Cd) can cause animal organism damage, but there have been few studies on the damage of cadmium to the immune organs of birds. Most fungal polysaccharide has antioxidant and immunomodulatory effects. The experimental study investigated the effects of fungal polysaccharide (Agaricus blazei Murill polysaccharide and Ganoderma luciduccharide) on the oxidative damage of central immune organs (thymus and bursa of Fabricius) and on the Toll-like receptor 4 (TLR4) pathway in cadmium-poisoned chickens. The results showed that Agaricus blazei polysaccharide and Ganoderma lucidum polysaccharide can reduce cadmium content, TLR4 expression, inflammatory factor (IL-1β, IL-6, TNF-α) content, and lipid peroxidation product MDA content and increase the activity of antioxidant enzymes SOD and GSH-Px in thymus and bursa of cadmium poisoning chickens. Ganoderma lucidum polysaccharide could decrease the expression of TLR4, IL-1β, and IL-6 in cadmium poisoning peripheral blood lymphocytes of chicken, and TLR4 inhibitor had the same effect. The results demonstrated the protective effects of Agaricus blazei Murill polysaccharide and Ganoderma lucidum polysaccharides on the damage of the central immune organs of chickens caused by cadmium poisoning were closely related to the TLR4 signaling pathway and oxidative stress.

Effect of miR-495 on lower extremity deep vein thrombosis through the TLR4 signaling pathway by regulation of IL1R1

Lower extremity deep vein thrombosis (LEDVT), a common peripheral vascular disease caused by a blood clot in a deep vein is usually accompanied by swelling of the lower limbs. MicroRNAs (miRs) have been reported to play roles in LEDVT. We aimed to investigate the effect of miR-495 on LEDVT via toll-like receptor 4 (TLR4) signaling pathway through interleukin 1 receptor type 1 (IL1R1). LEDVT mouse model was established, and the femoral vein (FV) tissues were collected to detect expressions of miR-495, IL1R1, and TLR4 signaling-related genes. The expressions of both CD31 and CD34 (markers for endothelial progenitor cells) in the FV endothelial cells as well as the proportion of CD31⁺/CD34⁺ cells in peripheral blood were measured in order to evaluate thrombosis. The effect of miR-495 on cell viability, cell cycle, and apoptosis was analyzed. IL1R1 was confirmed as the target gene of miR-495. Besides, inhibiting the miR-495 expression could increase IL1R1 expression along with activating the TLR4 signaling pathway. The total number of the leukocytes along with the ratio of weight to length of thrombus in the FV tissue showed an increase. The overexpression of miR-495 could promote FV endothelial cell viability. By injecting agomiR-495 and antagomiR-495 in vivo, the number of leukocytes in the FV tissues and the ratio of weight to length of thrombus were significantly decreased in the mice injected with the overexpressed miR-495, and the IL1R1/TLR4 signaling pathway was inhibited. Collectively, overexpressed miR-495 directly promotes proliferation while simultaneously inhibiting apoptosis of FV endothelial cells, alleviating FV thrombosis by inhibiting IL1R1 via suppression of TLR4 signaling pathway.

MicroRNA-335-5p suppresses lower extremity deep venous thrombosis by targeted inhibition of PAI-1 via the TLR4 signalingpathway

This study aims to investigate the effects of microRNA-335-5p (miR-335-5p) on lower-extremity deep vein thrombosis (LEDVT) by targeting PAI-1 through the TLR4 signaling pathway in rat models. siRNA, mimic, and inhibitor were used for transfection. The miR-335-5p expression was detected by in situ hybridization. CCK-8 assay and flow cytometry were adopted to detect proliferation, cell cycle, and apoptosis, respectively. Scratch test and Matrigel-based tube formation assay were used to detect the effect of miR-335-5p on cell migration ability and tube formation ability. A miR-335-5p lentivirus plasmid was constructed and injected into LEDVT rats. The length and weight of thrombus were measured, changes of thrombus recanalization were observed by CD34 immunohistochemistry, and levels of PAI-1 and inflammatory factors in femoral vein blood were detected by ELISA. LEDVT rats showed a higher AOD value of PAI-1, higher expression of PAI-1, NF-κB, Rac1, IL-1β, and TLR4 and a lower miR-335-5p expression. PAI-1 and miR-335-5p were negatively correlated. Compared to the blank and siRNA-NC groups, the miR-335-5p mimic and siRNA-PAI-1 groups showed declined expression of PAI-1, TLR4, NF-κB, Rac1, and IL-1β, increased proliferation and tube formation abilities, less cells in G0/G1 phase, and decreased apoptosis, decreased length and weight of thrombus, organized thrombus, increased new blood vessels, and decreased levels of PAI-1, IL-1, IL-6, and Tnf-a. miR-335-5p may suppress the occurrence and development of LEDVT in rats by repressing the activation of the TLR4 signaling pathway by targeted inhibition of PAI-1.

The Effects of Agaricus blazei Murill Polysaccharides on Cadmium-Induced Apoptosis and the TLR4 Signaling Pathway of Peripheral Blood Lymphocytes in Chicken

In this study, we investigated the effects of Agaricus blazei Murill polysaccharides (ABP) on cadmium (Cd)-induced apoptosis and the TLR4 signaling pathway of chicken peripheral blood lymphocytes (PBLs). Seven-day-old healthy chickens were randomly divided into four groups, and each group contained 20 males. The cadmium-supplemented diet group (Cd group) was fed daily with full feed that contained 140 mg cadmium chloride (CdCl₂)/kg and 0.2 mL saline. The A. blazei Murill polysaccharide diet group (ABP group) was fed daily with full feed with 0.2 mL ABP solution (30 mg/mL) by oral gavage. The cadmium-supplemented plus A. blazei Murill polysaccharide diet group (Cd + ABP group) was fed daily with full feed containing 140 mg CdCl₂/kg and 0.2 mL ABP solution (30 mg/mL) by gavage. The control group was fed daily with full feed with 0.2 mL saline per day. We measured the apoptosis rate and messenger RNA (mRNA) levels of apoptosis genes (caspase-3, Bax, and Bcl-2), the mRNA levels of TLR4 and TLR4 signaling pathway-related factors (MyD88, TRIF, NF-κB, and IRF3), the TLR4 protein expression, and the concentrations of inflammatory cytokines (IL-1β, IL-6, and TNF-α) in chicken PBLs. The results showed that the PBL apoptosis rate was significantly increased, the mRNA levels of caspase-3 and Bax were significantly increased, while that of Bcl-2 was significantly reduced. The Bax/Bcl-2 ratio was significantly increased in the Cd group at 20, 40, and 60 days after treatment compared with that in the control group. After treatment with ABP, the above changes were clearly suppressed. At the same time, ABP reduced the concentrations of IL-1β, IL-6, and TNF-α induced by Cd. We also found that ABP inhibited the TLR4 mRNA level and protein expression and inhibited the mRNA levels of MyD88, TRIF, NF-κB, and IRF3. The results demonstrated that Cd could induce apoptosis, activate the TLR4 signaling pathway, and induce the expression of inflammatory cytokines in chicken PBLs, and that the administration of ABP clearly inhibited Cd-induced effects on chicken PBLs.

Characterization and anti-inflammation role of swine IFITM3 gene

IFITM3 is involved in cell adhesion, apoptosis, immune, and antivirus activity. Furthermore, IFITM3 gene has been considered as a preferential marker for inflammatory diseases, and positive correlation to pathological grades. Therefore, we assumed that IFITM3 was regulated by different signal pathways. To better understand IFITM3 function in inflammatory response, we cloned swine IFITM3 gene, and detected IFITM3 distribution in tissues, as well as characterized this gene. Results indicated that the length of swine IFITM3 gene was 438 bp, encoding 145 amino acids. IFITM3 gene expression abundance was higher in spleen and lungs. Moreover, we next constructed the eukaryotic expression vector PBIFM3 and transfected into PK15 cells, finally obtained swine IFITM3 gene stable expression cell line. Meanwhile, we explored the effects of LPS on swine IFITM3 expression. Results showed that LPS increased IFITM3 mRNA abundance and exhibited time-dependent effect for LPS treatment. To further demonstrate the mechanism that IFITM3 regulated type I IFNs production, we also detected the important molecules expression of TLR4 signaling pathway. In transfected and non-transfected IFITM3 PK15 cells, LPS exacerbated the relative expression of TLR4-NFκB signaling molecules. However, the IFITM3 overexpression suppressed the inflammatory development of PK15 cells. In conclusion, these data indicated that the overexpression of swine IFITM3 could decrease the inflammatory response through TLR4 signaling pathway, and participate in type I interferon production. These findings may lead to an improved understanding of the biological function of IFITM3 in inflammation.

Porcine CD14 gene silencing partially inhibited the bacterial immune response mediated by TLR4 signaling pathway

Cluster of differentiation antigen 14 (CD14) is the membrane receptor protein in Toll-like Receptor 4 (TLR4) signaling pathway, which plays an important regulation role in not only innate immune response but also adaptive immune response. In this study, the pig kidney epithelial cell (PK15) line with CD14 gene silencing mediated by lentivirus was established and cells of CD14-RNAi and NC group were exposed to three kinds of Escherichia coli (E. coli F18ab, E. coli F18ac and E. coli K88ac) and LPS. Then qPCR and western blot were used to detect expression levels of TLR4 signaling pathway-related genes. Finally, ELISA was used to detect the level of proinflammatory cytokines in the cell culture supernatant. The results showed that the expression level of TLR4 signaling pathway-related genes in the entire signal pathway had obvious increases when cells were exposed to the stimulation induced by E. coli and LPS. In addition, the expression levels of CD14-RNAi group were overall significantly lower than NC group (P<0.05 or P<0.01), which was the same with the release levels of proinflammatory cytokines. This study revealed that pig CD14 gene silencing partially inhibited immune response to E. coli F18 invasion mediated by TLR4 signaling pathway.

Swine IRF3/IRF7 attenuates inflammatory responses through TLR4 signaling pathway

To explore the role of IRF3/IRF7 during inflammatory responses, we investigated the effects of swine IRF3/IRF7 on TLR4 signaling pathway and inflammatory factors expression in porcine kidney epithelial PK15 cell lines. We successfully constructed eukaryotic vectors PB-IRF3 and PB-IRF7, transfected these vectors into PK15 cells and observed GFP under a fluorescence microscope. In addition, RT-PCR was also used to detect transfection efficiency. We found that IRF3/IRF7 was efficiently overexpressed in PK15 cells. Moreover, we evaluated the effects of IRF3/IRF7 on the TLR4 signaling pathway and inflammatory factors by RT-PCR. Transfected cells were treated with lipopolysaccharide (LPS) alone, or in combination with a TBK1 inhibitor (LiCl). We revealed that IRF3/IRF7 enhanced IFNα production, and decreased IL-6 mRNA expression. Blocking the TBK1 pathway, inhibited the changes in IFNα, but not IL-6 mRNA. This illustrated that IRF3/IRF7 enhanced IFNα production through TLR4/TBK1 signaling pathway and played an anti-inflammatory role, while IRF3/IRF7 decreased IL-6 expression independent of the TBK1 pathway. Trends in MyD88, TRAF6, TBK1 and NFκB mRNA variation were similar in all treatments. LPS increased MyD88, TRAF6, TBK1 and NFκB mRNA abundance in PBR3/PBR7 and PBv cells, while LiCl blocked the LPS-mediated effects. The levels of these four factors in PBR3/PBR7 cells were higher than those in PBv. These results demonstrated that IRF3/IRF7 regulated the inflammatory response through the TLR4 signaling pathway. Overexpression of swine IRF3/IRF7 in PK15 cells induced type I interferons production, and attenuated inflammatory responses through TLR4 signaling pathway.

MFHAS1 suppresses TLR4 signaling pathway via induction of PP2A C subunit cytoplasm translocation and inhibition of c-Jun dephosphorylation at Thr239

TLR4, an important Toll-like receptor in innate immunity, can be activated by LPS and induce proinflammatory cytokines to resist invasion of pathogenic microorganism, but excessive inflammation can trigger tissue injury. Many genes negatively regulate TLR4 signaling pathway. Recent studies found that malignant fibrous histiocytoma amplified sequence 1 (MFHAS1) suppressed the expression of cytokine IL6 in Raw264.7 cells stimulated by LPS, but the mechanisms remained unclear. This study investigated the role of MFHAS1 in TLR4 signaling pathway and the possible mechanisms implicated. The results indicated that the expression of MFHAS1 was significantly increased in cells stimulated with LPS. Up-regulation of MFHAS1 effectively suppressed inflammatory cytokine expression in cells exposed to LPS, whereas down-regulation of MFHAS1 markedly increased inflammatory cytokines expression. Co-immunoprecipitation, pull-down and immunofluorescence tests demonstrated that MFHAS1 combined with the B and C subunits of PP2A and induced cytoplasm translocation of the C subunit, leading to decrease dephosphorylation of c-Jun at Thr239 and increase degradation of c-Jun. Reduction of c-Jun protein results in decreased AP-1 activity, which is independent of inhibition of JNK or p38MAPK phosphorylation. Taken together, these results indicate that MFHAS1 suppresses TLR4 signaling pathway through induction of PP2A C subunit cytoplasm translocation and subsequent c-Jun degradation, leading finally to decrease AP-1 activity and cytokines expression.

Astragaloside IV attenuates cognitive impairments induced by transient cerebral ischemia and reperfusion in mice via anti-inflammatory mechanisms

Astragaloside IV (AS-IV) is the main active component isolated from the traditional Chinese medicinal herb Astragalus membranaceus. Studies have demonstrated that AS-IV has neuroprotective effects in cerebral ischemic models. In this study, we aimed to investigate the effects of AS-IV on memory impairment induced by transient cerebral ischemia and reperfusion in mice, as well as the associated signaling mechanisms. Severe memory deficits were induced by bilateral common carotid artery occlusion (BCCAO) in mice as indicated in the Morris water maze test in this study. Oral administration of AS-IV (10 and 20mg/kg, once per day, started 7days before surgery and continued for 7days after surgery) significantly attenuated memory impairment and neuroinflammation. Moreover, AS-IV treatment significantly reduced the expression of toll-like receptor-4 (TLR4) and its downstream adaptor proteins, including myeloid differentiation primary response gene 88 (MyD88), toll/interleukin-1 receptor-domain containing adaptor-inducing interferon-β (TRIF) and tumour necrosis factor receptor associated factor-6 (TRAF6), and subsequently inhibited NF-κB phosphorylation. It is well-known that cerebral ischemia and reperfusion injury enhances the formation of reactive oxygen species (ROS) and further neuroinflammation. Importantly, we found that AS-IV suppressed NLRP3 inflammasome activation by controlling ROS production. In addition, AS-IV markedly reduced overactivation of microglia and the overexpression of inflammatory cytokines in the hippocampus compared with the transient cerebral ischemia and reperfusion group. These results suggest that AS-IV might possess neuroprotective effects against transient cerebral ischemia and reperfusion partly through its anti-inflammatory effects by inhibiting TLR4 signaling pathway and NLRP3 inflammasome overactivation.

Dioscin ameliorates cerebral ischemia/reperfusion injury through the downregulation of TLR4 signaling via HMGB-1 inhibition

We previously reported the promising effect of dioscin against hepatic ischemia/reperfusion (I/R) injury, but its effect on cerebral I/R injury remains unknown. In this work, an in vitro oxygen-glucose deprivation and reoxygenation (OGD/R) model and an in vivo middle cerebral artery occlusion (MCAO) model were used. The results indicated that dioscin clearly protected PC12 cells and primary cortical neurons against OGD/R insult and significantly prevented cerebral I/R injury. Further research demonstrated that dioscin-induced neuroprotection was accompanied by a significant inhibition in the expression and the nuclear to cytosolic translocation of HMGB-1, reflected by decreased TLR4 expression. Blockade of the TLR4/MyD88/TRAF6 signaling pathway by dioscin inhibited NF-κB and AP-1 transcriptional activities, MAPK and STAT3 phosphorylation, and pro-inflammatory cytokine responses, and upregulated the levels of anti-inflammatory factors. In addition, small interfering RNA (siRNA) and overexpressed genes of HMGB-1 and TLR4 were applied in in vitro experiments, respectively, and the results further confirmed that dioscin showed an efficient neuroprotection because of its inhibiting effects on HMGB-1/TLR4 signaling and subsequent suppressing inflammation. These findings provide new insights that will aid in elucidating the effect of dioscin against cerebral I/R injury and support the development of dioscin as a potential treatment for ischemic stroke.