Rational design of peptide derivatives for inhibition of MyD88‐mediated toll‐like receptor signaling in human peripheral blood mononuclear cells and epithelial cells exposed to Francisella tularensis

Small molecules were developed to attenuate proinflammatory cytokines resulting from activation of MyD88‐mediated toll‐like receptor (TLR) signaling by Francisella tularensis. Fifty‐three tripeptide derivatives were synthesized to mimic a key BB‐loop region involved in toll‐like/interleukin‐1 receptor recognition (TIR) domain interactions. Compounds were tested for inhibition of TNF‐α, IFN‐γ, IL‐6, and IL‐1β in human peripheral blood mononuclear cells (PBMCs) and primary human bronchial epithelial cells exposed to LPS extracts from F. tularensis. From 53 compounds synthesized and tested, ten compounds were identified as effective inhibitors of F. tularensisLPS‐induced cytokines. Compound stability testing in the presence of human liver microsomes and human serum resulted in the identification of tripeptide derivative 7 that was a potent, stable, and drug‐like small molecule. Target corroboration using a cell‐based reporter assay and competition experiments with MyD88 TIR domain protein supported that the effect of 7 was through MyD88 TIR domain interactions. Compound 7 also attenuated proinflammatory cytokines in human peripheral blood mononuclear cells and bronchial epithelial cells challenged with a live vaccine strain of F. tularensis at a multiplicity of infection of 1:5. Small molecules that target TIR domain interactions in MyD88‐dependent TLR signaling represent a promising strategy toward host‐directed adjunctive therapeutics for inflammation associated with biothreat agent‐induced sepsis.     

Pharmacological inhibition of TLR4/NF‐κB with TLR4‐IN‐C34 attenuated microcystin‐leucine arginine toxicity in bovine Sertoli cells

This study investigated the pharmacological inhibition of the toll‐like receptor 4 (TLR4) genes as a measure to attenuate microcystin‐LR (MC‐LR) reproductive toxicity. Bovine Sertoli cells were pretreated with TLR4‐IN‐C34 (C34) for 1 hour. Thereafter the pretreated and non‐pretreated Sertoli cells were cultured in medium containing 10% heat‐activated fetal bovine serum + 80 μg/L MC‐LR for 24 hours to assess the ability of TLR4‐IN‐C34 to attenuate the toxic effects of MC‐LR. The results showed that TLR4‐IN‐C34 inhibited MC‐LR‐induced mitochondria membrane damage, mitophagy and downregulation of blood‐testis barrier constituent proteins via TLR4/nuclear factor‐kappaB and mitochondria‐mediated apoptosis signaling pathway blockage. The downregulation of the mitochondria electron transport chain, energy production and DNA replication related genes (mt‐ND2, COX‐1, COX‐2, ACAT, mtTFA) and upregulation of inflammatory cytokines (interleukin [IL]‐6, tumor necrosis factor‐α, IL‐1β, interferon‐γ, IL‐4, IL‐10, IL‐13 and transforming growth factor β1) were modulated by TLR4‐IN‐C34. Taken together, we conclude that TLR4‐IN‐C34 inhibits MC‐LR‐related disruption of mitochondria membrane, mitophagy and downregulation of blood‐testis barrier proteins of the bovine Sertoli cell via cytochrome c release and TLR4 signaling blockage.     

Toll‐like receptor 4 ablation rescues against paraquat‐triggered myocardial dysfunction: Role of ER stress and apoptosis

Paraquat is a nitrogen herbicide imposing severe organ toxicity in human leading to acute lung injury and heart failure. The present study was designed to examine the impact of ablation of the innate proinflammatory mediator toll‐like receptor 4 (TLR4) in paraquat‐induced cardiac contractile dysfunction and the underlying mechanisms involved with a focus on endoplasmic reticulum (ER) stress and apoptosis. Adult male wild‐type (WT) and TLR4 knockout (TLR4^?/?) mice were challenged with paraquat (45 mg/kg, i.p.) for 48 h prior to the assessment of myocardial and cardiomyocyte sarcomere function, ER stress, apoptosis and inflammation. Acute paraquat challenge exerted myocardial functional and geometric alterations including enlarged left ventricular end systolic diameter (LVESD), reduced fractional shortening, decreased sarcomere shortening, maximal velocities of sarcomere shortening and relengthening associated with unchanged LV posterior wall thickness, septal thickness, LV end diastolic diameter (LVEDD), heart rate, sarcomere length, time‐to‐peak shortening and time‐to‐90% relengthening. Although TLR4 ablation did not affect mechanical properties in the heart, it significantly attenuated or ablated paraquat‐induced cardiac contractile anomalies. Moreover, paraquat imposed overt ER stress, apoptosis and inflammation as evidenced by upregulation of Bip, CHOP, Caspase‐3, ?9, Bax, Bad, and IL‐1β, phosphorylation of PERK, eIF2α and IΚB, as well as activation of the stress molecules ERK and p38, with unchanged Caspase‐8, Bcl2, TNF‐α, p53, HMGB1, MyD88 and phosphorylation of Akt, GSK3β and JNK, the effects of which were attenuated or negated by TLR4 knockout. Taken together, our results suggested that TLR4 ablation alleviated paraquat‐induced myocardial contractile dysfunction possibly through attenuation of ER stress, apoptosis and inflammation. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 656–668, 2017.     

Downregulation of toll‐like receptor 4 and IL‐6 following irradiation of the rat urinary bladder

The pathophysiology behind radiation cystitis is poorly understood. Here we investigated whether bladder irradiation affects the immune system of the rat urinary bladder. Female rats were sedated and exposed to one single radiation dose of 20 Gy or only sedated (controls) and killed 16 h to 14 days later. Rats were placed in a metabolic cage at 16 h, 3 days, 7 days and 14 days following bladder irradiation. The urinary bladders were harvested and analysed with qPCR, immunohistochemistry and/or Western blot for the expression of interferon (IFN)‐γ, interleukin (IL)‐1β, IL‐2, IL‐4, IL‐5, IL‐6, IL‐10, IL‐13, nitric oxide synthases (eNOS, iNOS and nNOS), tumour necrosis factor (TNF)‐α and toll‐like receptor 4 (TLR4). Urine was collected and analysed for IL‐6 and nitrite (reflecting nitric oxide activity) with ELISA and the Griess reaction, respectively. Irradiation increased bladder frequency and decreased voiding volumes 14 days following bladder irradiation. Bladder irradiation increased the expression of IL‐10 and collagen in the bladder, while TLR4 and IL‐6 expressions were decreased in the urothelium concomitantly with a decrease in mast cells in the submucosa and urine levels of IL‐6 and nitrite. The present findings show that bladder irradiation leads to urodynamic changes in the bladder and may suppress important immunoregulatory pathways in the urinary bladder.     

PM10‐biogenic fraction drives the seasonal variation of proinflammatory response in A549 cells

PM10 was collected in a Milan urban site, representative of the city air quality, during winter and summer 2006. Mean daily PM10 concentration was 48 μg m^?3 during summer and 148 μg m^?3 during winter. Particles collected on Teflon filters were chemically characterized and the endotoxin content determined by the LAL test. PM10‐induced cell toxicity, assessed with MTT and LDH methods, and proinflammatory potential, monitored by IL‐6 and IL‐8 cytokines release, were investigated on the human alveolar epithelial cell line A549 exposed to increasing doses of PM. Besides untreated cells, exposure to inert carbon particles (2–12 μm) was also used as additional control. Both cell toxicity and proinflammatory potency resulted to be higher for summer PM10 with respect of winter PM10, with IL‐6 showing the highest dose‐dependent release. The relevance of biogenic components adsorbed onto PM10 in eliciting the proinflammatory mediators release was investigated by inhibition experiments. Polymixin B (Poly) was used to inhibit particle‐bind LPS while Toll‐like receptor‐2 antibody (a‐TLR2) to specifically block the activation of this receptor. While cell viability was not modulated in cells coexposed to PM10 and Poly or a‐TLR2 or both, inflammatory response did it, with IL‐6 release being the most inhibited. In conclusion, Milan PM10‐induced seasonal‐dependent biological effects, with summer particles showing higher cytotoxic and proinflammatory potential. Cytotoxicity seemed to be unaffected by the PM biogenic components, while inflammation was significantly reduced after the inhibition of some biogenic activated pathways. Besides, the PM‐associated biogenic activity does not entirely justify the PM‐induced inflammatory effects. © 2010 Wiley Periodicals, Inc. Environ Toxicol 2012.     

Dexmedetomidine preconditioning for myocardial protection in ischaemia‐reperfusion injury in rats by downregulation of the high mobility group box 1‐toll‐like receptor 4‐nuclear factor κB signalling pathway

Pharmacological preconditioning reduces myocardial infarct size in ischaemia‐reperfusion (I‐R) injury. Dexmedetomidine, a selective α₂‐adrenoceptor agonist, has a proven cardioprotective effect when administered prior to I‐R, although the underlying mechanisms for this effect are not fully understood. We evaluated whether dexmedetomidine preconditioning could induce a myocardio‐protective effect against I‐R injury by inhibiting associated inflammatory processes through downregulation of the high mobility group box 1 (HMGB1)‐toll‐like receptor 4 (TLR4)‐nuclear factor κB (NF‐κB) signalling pathway. Seventy rats were randomly assigned to seven groups: a control and six test groups, involving I‐R for 30 and 120 minutes, respectively, in isolated rat hearts and different pretreatment protocols with dexmedetomidine (10 nmol/L) as well as yohimbine (1 μmol/L) and recombinant HMGB1 peptide (rHMGB1; 20 μg/L), alone or in combination with dexmedetomidine. Cardiac function was recorded; myocardial HMGB1, TLR4, and NF‐κB activities and levels of tumour necrosis factor‐α (TNF‐α) and interleukin‐6 (IL‐6) were measured as were lactate dehydrogenase (LDH) and creatine kinase (CK) in coronary outflow. Dexmedetomidine preconditioning significantly improved cardiac function (P<.05), downregulated the expression of HMGB1‐TLR4‐NF‐κB, reduced levels of TNF‐α and IL‐6 in isolated ventricles during I‐R injury, and significantly reduced CK and LDH levels in coronary outflow (P<.05). All of these effects were partially reversed by yohimbine (P<.05) or rHMGB1 (P<.05). Dexmedetomidine preconditioning alleviated myocardial I‐R injury in rats through inhibition of inflammatory processes associated with downregulation of the HMGB1‐TLR4‐NF‐κB signalling pathway via activation at α₂‐adrenergic receptors.     

Effects of xenoestrogens in human M1 and M2 macrophage migration,cytokine release,and estrogen‐related signaling pathways

Bisphenol A (BPA), bis(2‐ethylhexyl)phthalate (DEHP) and di(n‐butyl)phthalate (DBP) are environmental estrogens that have been associated with a wide range of adverse health outcomes for which inflammation has also been hypothesized as a potentially involved mechanism and where macrophages play a central role. This study was carried out to evaluate if xenoestrogen (XE) treatment of classically (M1) or alternatively (M2) activated macrophages could affect their behavior. For this purpose, human peripheral blood monocyte‐derived macrophages either unstimulated or activated with lipopolysaccharide (100 ng/mL, M1) or with interleukin (IL) 4 (15 ng/mL, M2) were treated with 17β‐estradiol (E₂), BPA, DEHP and DBP alone or in combination with selective ERα or ERβ antagonists. Migratory capability, cytokine release, and estrogen‐associated signaling pathways were evaluated to assess macrophage function. All tested XEs had a tendency to stimulate M2 migration, an effect that followed the same direction than E₂. Moreover, all XEs significantly induced IL10 in M1 and decreased IL6 and globally decreased IL10, IL6, TNFα, and IL1β release by M2 macrophages. However, DEHP and DBP significantly increased IL1β release in M1 and M2 macrophages, respectively. Some of the effects described above were shown to be mediated by either ERα or ERβ and were simultaneous to modulation of NF‐κB, AP1, JNK, or ERK signaling pathways. We provide new evidence of the effect of XE on macrophage behavior and their mechanisms with relevance to the understanding of the action of environmental chemicals on the immune system and inflammation‐associated diseases. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1496–1509, 2016.     

Cyanidin‐3‐glucoside inhibits inflammatory activities in human fibroblast‐like synoviocytes and in mice with collagen‐induced arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by joint tissue inflammation. Cyanidin‐3‐glucoside (C3G) is a major component in the flavonoid family and has shown anti‐inflammatory, anti‐oxidant and anti‐tumour activity. In this study, we investigated the effects of C3G on lipopolysaccharides (LPS)‐induced inflammation on human rheumatoid fibroblast‐like synoviocytes (FLS) and on collagen‐induced arthritis (CIA) mice model. We treated FLS with C3G followed by LPS induction, the expressions of tumour necrosis factor alpha (TNF‐α), interleukin 1 beta (IL‐1β) and IL‐6 and the activation of nuclear factor kappa‐light‐chain‐enhancer of activated B cells (NF‐κB) and mitogen‐activated protein kinase (MAPK) signalling pathway were analyzed. CIA was induced in mice and the arthritic mice were treated with C3G for 3 weeks. The disease severity was compared between control and C3G treated mice. The serum levels of TNF‐α, IL‐1β and IL‐6 were analyzed by ELISA. C3G inhibited LPS‐induced TNF‐α, IL‐1β and IL‐6 expression in FLS. Moreover, C3G inhibited LPS‐induced p65 production and IκBa, p38, ERK and JNK phosphorylation. Administration of C3G significantly attenuated disease in mice with CIA and decreased the serum level of TNF‐α, IL‐1β and IL‐6. C3G inhibited LPS‐induced inflammation in human FLS by inhibiting activation of NF‐κB and MAPK signalling pathway. C3G exhibited therapeutic effects in mice with CIA.     

Atractylodin attenuates lipopolysaccharide-induced acute lung injury by inhibiting NLRP3 inflammasome and TLR4 pathways

Acute lung injury (ALI) arises from uncontrolled pulmonary inflammation with high mortality rates. Atractylodin (Atr) is a polyethylene alkynes and has been reported to possess anti-inflammation effect. Thus, we aimed to investigate the protective effect of Atr on lipopolysaccharide (LPS)-induced inflammatory responses ALI. The results indicated that Atr treatment not only significantly attenuated LPS-stimulated histopathological changes but also lessened the myeloperoxidase (MPO) activity, the wet-to-dry weight ratio of the lungs, protein leakage and infiltration of inflammatory cells. Moreover, Atr inhibited the tumor necrosis factor (TNF)-α, interleukin (IL)-6, IL-1β and monocyte chemoattractant protein (MCP)-1 secretion in BALF. Further study demonstrated that such inhibitory effects of Atr were due to suppression of nucleotide-binding domain-(NOD-) like receptor protein 3 (NLRP3) inflammasome and toll like receptor 4 (TLR4) activation, likely contributing to its anti-inflammatory effects. Collectively, these findings suggest that Atr may be an effective candidate for alleviating LPS-induced inflammatory responses.     

Molecular pathways mediating differential responses to lipopolysaccharide between human and baboon arterial endothelial cells

1. Vascular inflammation plays a critical role in atherogenesis. Previously, we showed that baboon arterial endothelial cells (BAEC) were hyporesponsive to lipopolysaccharide (LPS) compared with human arterial endothelial cells (HAEC). 2. In the present study, we investigated mechanisms underlying differential responses between HAEC and BAEC to tumour necrosis factor (TNF)‐α and LPS. 3. Both HAEC and BAEC responded similarly to TNF‐α. However, BAEC showed retarded responses to LPS in expression of E‐selectin, intercellular adhesion molecule‐1, monocyte chemotactic protein‐1 and interleukin‐8 (P < 0.05). These changes were confirmed at the mRNA level. Tumour necrosis factor‐α activated nuclear factor‐κB members such as p50, p52, p65, c‐rel and RelB in both HAEC and BAEC. In contrast, LPS activated p50 and p65 only in HAEC. Using microarray assays, we found that TNF receptor‐associated factor 2 (TRAF‐2), TNF receptor superfamily, member 1A‐associated via death domain (TRADD) and nuclear factors such as nuclear factor of kappa in B‐cells inhibitor, α (NFKBIA) and nuclear factor of kappa in B‐cells inhibitor, β (NFKBIB) were upregulated by LPS only in HAEC. Although the baseline expression of Toll‐like receptor (TLR) 4 was low in both HAEC and BAEC, TNF‐α activated TLR4 expression in both cell types. Although LPS increased TLR4 expression only in HAEC, human and baboon peripheral blood mononuclear cells exhibited similar TLR4 expression and response to LPS. Transfecting BAEC with TLR4/myeloid differentiation protein‐2 overexpression vector conferred BAEC responsiveness to LPS. 4. The findings of the present study indicate that an altered TLR4 system may be responsible for the resistance of baboon endothelial cells to LPS. Given the importance of TLR4 in human immune responses and vascular diseases, the natural resistance of baboons to LPS/TLR4‐initiated inflammation could make the baboon a valuable animal model in which to study how inflammation affects atherogenesis.     

Enrichment Assessment of Multiple Virtual Screening Strategies for Toll‐Like Receptor 8 Agonists Based on a Maximal Unbiased Benchmarking Data Set

Toll‐like receptor 8 agonists, which activate adaptive immune responses by inducing robust production of T‐helper 1‐polarizing cytokines, are promising candidates for vaccine adjuvants. As the binding site of toll‐like receptor 8 is large and highly flexible, virtual screening by individual method has inevitable limitations; thus, a comprehensive comparison of different methods may provide insights into seeking effective strategy for the discovery of novel toll‐like receptor 8 agonists. In this study, the performance of knowledge‐based pharmacophore, shape‐based 3D screening, and combined strategies was assessed against a maximum unbiased benchmarking data set containing 13 actives and 1302 decoys specialized for toll‐like receptor 8 agonists. Prior structure–activity relationship knowledge was involved in knowledge‐based pharmacophore generation, and a set of antagonists was innovatively used to verify the selectivity of the selected knowledge‐based pharmacophore. The benchmarking data set was generated from our recently developed ‘mubd‐decoymaker ’ protocol. The enrichment assessment demonstrated a considerable performance through our selected three‐layer virtual screening strategy: knowledge‐based pharmacophore ( Phar1 ) screening, shape‐based 3D similarity search ( Q4_combo ), and then a Gold docking screening. This virtual screening strategy could be further employed to perform large‐scale database screening and to discover novel toll‐like receptor 8 agonists.     

Attenuation of liver pro-inflammatory responses by Zingiber officinale via inhibition of NF-kappa B activation in high-fat diet-fed rats

Abstract: The aim of this study was to investigate whether treatment with a ginger (Zingiber officinale) extract of high‐fat diet (HFD)‐fed rats suppresses Nuclear factor‐kappa B (NF‐κB)‐driven hepatic inflammation and to subsequently explore the molecular mechanisms in vitro. Adult male Sprague‐Dawley rats were treated with an ethanolic extract of Zingiber officinale (400 mg/kg) along with a HFD for 6 weeks. Hepatic cytokine mRNA levels, cytokine protein levels and NF‐κB activation were measured by real‐time PCR, Western blot and an NF‐κB nuclear translocation assay, respectively. In vitro, cell culture studies were carried out in human hepatocyte (HuH‐7) cells by treatment with Zingiber officinale (100 μg/mL) for 24 hr prior to interleukin‐1β (IL‐1β, 8 ng/mL)‐induced inflammation. We showed that Zingiber officinale treatment decreased cytokine gene TNFα and IL‐6 expression in HFD‐fed rats, which was associated with suppression of NF‐κB activation. In vitro, Zingiber officinale treatment decreased NF‐κB‐target inflammatory gene expression of IL‐6, IL‐8 and serum amyloid A1 (SAA1), while it suppressed NF‐κB activity, IκBα degradation and IκB kinase (IKK) activity. In conclusion, Zingiber officinale suppressed markers of hepatic inflammation in HFD‐fed rats, as demonstrated by decreased hepatic cytokine gene expression and decreased NF‐κB activation. The study demonstrates that the anti‐inflammatory effect of Zingiber officinale occurs at least in part through the NF‐κB signalling pathway.     

Proanthocyanidin protects against cisplatin‐induced oxidative liver damage through inhibition of inflammation and NF‐κβ/TLR‐4 pathway

Although cisplatin (CIS) is a highly effective anticancer drug, hepatotoxicity is one of the most common adverse effects associated with its use. Recently, reactive oxygen species (ROS) and inflammation are suggested to be key factors in the pathophysiology of CIS‐induced acute liver damage. The aim of this study is to investigate the possible protective effect of proanthocyanidin (PRO) against CIS‐induced acute hepatotoxicity. Rats were divided into four groups: 1, Control; 2, PRO; 3, CIS; and 4, PRO + CIS. Biochemical studies and histopathology were used to assess liver damage. ROS, inflammatory cytokines, nuclear factor kappa beta (NF‐κβ), inducible cyclooxygenase enzyme (COX‐2), inducible nitric oxide synthase (iNOS), toll‐like receptor‐4 (TLR‐4) gene expression, and apoptotic markers were also assessed. PRO pretreatment protected the liver against CIS‐induced toxicity as indicated by decreased plasma levels of liver function enzymes and the normal liver histopathology observed in the PRO + CIS group. PRO pretreatment also diminished indicators of oxidative stress in the liver, including nitric oxide (NO) and malondialdehyde (MDA). It also increased the antioxidants, reduced glutathione (GSH), glutathione peroxidase (GPx), superoxide dismutase (SOD), and catalase (CAT) in the liver. Plasma interleukin‐1 beta (IL‐1β), IL‐6, and tumor necrosis factor‐alpha (TNF‐α) were all reduced. Liver gene expression of NF‐κβ, COX‐2, iNOS, and TLR‐4 were all downregulated. Furthermore, PRO administration downregulated the liver expression of the apoptotic marker, Bax, while upregulated the antiapoptotic marker, Bcl2. In conclusion, our results revealed that PRO may protect against CIS‐induced acute liver damage mainly through inhibition of ROS, inflammation, and apoptosis.     

Size‐dependent superparamagnetic iron oxide nanoparticles dictate interleukin‐1β release from mouse bone marrow‐derived macrophages

Superparamagnetic iron oxide nanoparticles (SPIONs) have been widely investigated for their biomedical applications in magnetic resonance imaging, targeting therapy, cell labeling, etc. It has been well documented that macrophages produce interleukin (IL)‐1β via several signaling pathways, such as inflammasome activation in response to particles including silica, asbestos and urea crystals with lipopolysaccharide priming. However, the size and dose effects of SPIONs on macrophages and the mechanisms remain unclear. In this study, we explored the cytotoxicity and mechanisms of the synthesized SPIONs with different size distributions of 30, 80 and 120 nm, and compared their potential capability in inducing IL‐1β release in mouse bone marrow‐derived macrophages (BMMs). We found that SPIONs induced IL‐1β release in a size‐ and dose‐dependent manner, in which the smallest SPIONs triggered the highest IL‐1β in BMMs. When cellular uptake of SPIONs was inhibited by the actin polymerization inhibitor, cytochalasin D, SPION‐induced IL‐1β release was suppressed in BMMs. Preventing lysosome damage with bafilomycin A1 or CA‐074‐Me also counteracted SPION‐induced IL‐1β release. Moreover, SPION‐activated IL‐1β release was also attenuated by reactive oxygen species scavengers, diphenylene iodonium or N‐acetylcysteine. Our results elucidated the effects of size and dose on the cytotoxicity and mechanisms of IL‐1β release of SPIONs on macrophages, which facilitate the theoretical and experimental application of SPIONs in biotechnology and biomedicine in the future.     

Protective effects of curcumin against hepatic fibrosis induced by carbon tetrachloride: Modulation of high-mobility group box 1, Toll-like receptor 4 and 2 expression

The aim of the study was to investigate the effect of curcumin on the liver fibrosis induced by carbon tetrachloride (CCl₄) in rats, and to elucidate its underlying molecular mechanisms. Rats were administered with CCl₄ together with or without curcumin for 6 weeks. Hepatic damage was evaluated by analysis of liver function tests in serum. Hepatic histopathology and collagen content were employed to quantify liver fibrosis; and activated hepatic stellate cells were assessed. Moreover, the mRNA and protein expression levels of interleukin (IL)-6, tumor necrosis factor (TNF)-α, monocyte chemotactic protein (MCP)-1, high-mobility group box 1 (HMGB1), Toll like receptor (TLR) 2 and TLR4 were determined by quantitative real time PCR, Western blot or immunohistochemistry. Treatment with curcumin significantly attenuated CCl₄-induce liver injury, hepatic inflammation and reduced the levels of proinflammatory mediators (TNF-α, IL-6 and MCP-1). Moreover, curcumin significantly inhibited extracellular matrix deposition, reduced the number of activated stellate cells, and decreased the levels of HMGB1, TLR4 and TLR2 expression in the rat model of fibrogenesis. These results suggest that curcumin could be an effective agent for preventing liver fibrosis and its mechanism may in part be a consequence of the reduction TLR2, TLR4 and HMGB1 expression.     

Strains of Group B streptococci from septic patients induce platelet activation via Toll‐like Receptor 2

Group B Streptococcus (GBS) causes life‐threatening bacterial sepsis, especially in newborns and pregnant women. Patients suffering from sepsis often display low platelet counts, characterized by thrombocytopenia, because of platelet activation. In the present study, the roles of six GBS strains from septic patients in platelet aggregation, as well as the underlying mechanisms, were investigated. Incubation of platelets with three of the strains induced platelet aggregation, increased the secretion of cellular adhesin molecule CD62P and activation of GPIIb/IIIa. Furthermore, the GBS strains that induced platelet activation also caused an increase in the expression of Toll‐like receptor (TLR) 2 in platelets. Pre‐incubation of platelets with anti‐TLR2 monoclonal antibody, but not anti‐TLR4 monoclonal antibody, inhibited these functional responses induced by GBS. TLR2 stimulation also activated the phosphoinositide 3‐kinase (PI3‐K)/Akt signalling pathway in platelets, and inhibition of PI3‐K significantly reduced GBS‐induced platelet responses. Our results indicate that three of the GBS strains from the septic patients can trigger platelet activation by interacting with platelets, which involves the elevation of platelet TLR2 expression.