Ramulus Cinnamomi extract attenuates neuroinflammatory responses via downregulating TLR4/MyD88 signaling pathway in BV2 cells

Ramulus Cinnamomi （RC）, a traditional Chinese herb, has been used to attenuate inflammatory responses. The purpose of this study was to investigate the effect of RC extract on lipopolysaccharide （LPS）-induced neuroinflammation in BV2 microglial cells and the underlying mechanisms involved. BV2 cells were incubated with normal medium （control group）, LPS, LPS plus 30 pg/mL RC extract, or LPS plus 100 pg/mL RC extract. The BV2 cell morphology was observed under an optical microscope and cell viability was detected by MTT assay. Nitric oxide level in BV2 cells was detected using Griess regents, and the levels of interleukin-6, interleukin-1 β, and tumor necrosis factor u in BV2 cells were determined by ELISA. The expression levels of cyclooxygenase-2, Toll-like receptor 4 and myeloid differentiation factor 88 proteins were detected by western blot assay. Compared with the LPS group, both 30 and 100 μg/mL RC extract had no significant effect on the viability of BV2 cells. The levels of nitric oxide, interleukin-6, interleukin-1β and tumor necrosis factor ct in BV2 cells were all significantly increased after LPS induction, and the levels were significantly reversed after treatment with 30 and 100 μg/mL RC extract. Furthermore, RC extract significantly inhibited the protein expression levels of cyclooxygenase-2, Toll-like receptor 4 and myeloid differentiation factor 88 in LPS-induced BV2 cells. Our findings suggest that RC extract alleviates neuroinflammation by downregulating the TLR4/MyD88 signaling pathway.

Effect of dexmedetomidine on the prevention of PSH in patients with severe craniocerebral injury by regulating TLR4/My D88/NF-kappa B signaling pathway

Objective:To investigate the clinical efficacy of dexmedetomidine in the regulation of TLR4/My D88/NF-κB in the prevention of paroxysmal sympathetic over-excitation (PSH) in patients with severe head injury. Methods:One hundred patients with severe head injury who were admitted to our hospital from September 2016 to May 2019 were enrolled. The randomized digital table method was divided into 50 cases in the study group and the control group. Patients in the study group were given dexmedetomidine at a dose of 1.0 μg/kg before anesthesia induction, followed by infusion at 0.4 μg / (kg·h), and the control group was injected with the same amount of normal saline. The incidence of PSH, clinical symptoms, imaging findings, mechanical ventilation time, tracheal intubation/incision duration, ICU hospitalization time, total length of hospital stay, and GCS scores three months after discharge were compared between the two groups. At the same time, the fluorescence intensity, TLR4, NF-κB expression level and tumor necrosis factor-α (TNF-α) expression levels in peripheral blood CD14+ monocytes of the two groups were detected. Results:The incidence of PSH was significantly lower in the study group than in the control group at 7 and 3 months (P<0.05). The total length of hospital stay, duration of ICU hospitalization, intraoperative tracheotomy, and mechanical ventilation time were significantly lower in the study group than in the control group. And the GCS score was higher than the control group, and the difference was statistically significant (P<0.05). In addition, the imaging results showed that there were some differences in the location of imaging lesions between the two groups. The proportion of lesions in the ventricular system and surrounding areas was higher in the control group than in the study group (P<0.05). And the T14-T3 CD14+ PBMC MyD88 fluorescence intensity, TLR4 and NK-κB positive expression rate were significantly higher than those of T0 (P<0.05), but the MyD88 fluorescence intensity, TLR4 and NK-κB positive expression rate in the study group were significantly lower than those in the control group at T1~T3 (P<0.05). The levels of serum TNF-α in T1~T3 groups were significantly higher than those in T0 (P<0.05), but the levels of serum TNF-α in T1~T3 in the study group were significantly lower than those in the control group (P< 0.05). Conclusions:Dexmedetomidine can reduce the oxidative stress response in patients with severe head injury by inhibiting TLR4/My D88/NF-κB signaling pathway, thus effectively reducing the risk of PSH and improving the prognosis of patients.

基于TLR4/MyD88/AMPK信号通路探索“从风论治”治法治疗糖尿病肾病的作用机制

目的基于TLR4/MyD88/AMPK信号通路探索“从风论治”治法治疗糖尿病肾病(diabetic kidney disease,DKD)的作用机制。方法db/db小鼠分为对照组、糖尿病肾病组、干预组,干预时间为8周。留取血清、尿液,检测24小时尿蛋白定量、白细胞介素-6(interleukin-6,IL-6)、肿瘤坏死因子-α(tumor necrosis factor-α,TNF-α)的表达水平。留取肾组织,光镜下观察肾组织病理改变,同时采用Western blot法及免疫组织化学法检测肾组织Toll样受体4(Toll-like receptor 4,TLR4)、髓样分化因子(myeloid differentiation factor 88,MyD88)、AMP活化蛋白激酶(AMP-activated protein kinase,AMPK)、过氧化物酶体增殖物激活受体γ-辅激活因子1-α(peroxisome proliferator-activated receptorγcoactivator 1-alpha,PGC-1α)蛋白的相对表达情况。结果干预组24小时尿蛋白在药物干预后明显减少,且干预组与糖尿病肾病组对比差异有统计学意义。Elisa结果显示:干预组与糖尿病肾病组相比,db/db小鼠血清中IL-6水平与TNF-α水平均有降低,差异具有统计学意义(P<0.05)。对照组肾组织的肾小球结构完整,糖尿病肾病组系膜细胞及系膜基质均增生,间质少量炎细胞浸润,干预组较糖尿病肾病组有减轻。Western blot及免疫组化结果显示:干预组TLR4、MyD88蛋白表达程度明显低于糖尿病肾病组(P<0.01);干预组p-AMPK、PGC-1α蛋白的表达程度显著高于糖尿病肾病组(P<0.01),而干预组AMPK蛋白的表达水平与糖尿病肾病组差异无统计学意义(P>0.05)。结论“从风论治”治法通过TLR4/MyD88/AMPK信号通路能够减轻DKD炎性因子的表达延缓DKD进展。

Bioinformatic Analysis and Experimental Verification of QJHGD on Caerulein-induced Inflammatory Response in SAP Model Rats Based on TLR4/NF-κB/My D88 Pathway

[Objectives]To conduct bioinformatic analysis and experimental verification of Qingjie Huagong Decoction(QJHGD)on caerulein-induced inflammatory response in severe acute pancreatitis(SAP)model rats based on TLR4/NF-κB/MyD88 pathway.[Methods]The effective component groups and potential targets of QJHGD were collected by the network pharmacology method.A drug-component-target network was constructed.The GO and KEGG of targets were enriched and analyzed with the aid of Metascape database,and the target pathway related to SAP inflammation was screened.The SAP rat model was established by caerulein combined with lipopolysaccharide,and QJHGD was intragastrically administered.Pancreatic tissue was observed by HE staining.In addition,enzyme-linked immunosorbent assay and immunohistochemistry were used to verify the anti-inflammatory effect of QJHGD on SAP rats and its regulatory effect on TLR4/NF-κB/MyD88 target pathway.[Results]A total of 105 active components of QJHGD and 148 key targets of SAP were predicted and screened;KEGG was enriched in 320 different pathways including toll-like receptor and NF-κB classical pathways.Animal experiment verified that QJHGD reduced serum amylase,serum lipase activity,IL-6,TNF-αlevels in SAP rats;HE staining showed the effect of QJHGD on the pathological changes of pancreas,and QJHGD inhibited the positive expression of key proteins of TLR4,NF-κB and MyD88 in the inflammatory transduction pathway.[Conclusions]The mechanism of QJHGD improving pancreatic injury in SAP rats may be related to down-regulating the expression of key proteins in the TLR4/NF-κB/MyD88 pathway.

Novel compound FLZ alleviates rotenoneinduced PD mouse model by suppressing TLR4/MyD88/NF-kB pathway through microbiotaegutebrain axis

Parkinson’s disease(PD)is the second most common neurodegenerative disease,but none of the current treatments for PD can halt the progress of the disease due to the limited understanding of the pathogenesis.In PD development,the communication between the brain and the gastrointestinal system influenced by gut microbiota is known as microbiota-gut-brain axis.However,the explicit mechanisms of microbiota dysbiosis in PD development have not been well elucidated yet.FLZ,a novel squamosamide derivative,has been proved to be effective in many PD models and is undergoing the phase I clinical trial to treat PD in China.Moreover,our previous pharmacokinetic study revealed that gut microbiota could regulate the absorption of FLZ in vivo.The aims of our study were to assess the protective effects of FLZ treatment on PD and to further explore the underlying microbiota-related mechanisms of PD by using FLZ as a tool.In the current study,chronic oral administration of rotenone was utilized to induce a mouse model to mimic the pathological process of PD.Here we revealed that FLZ treatment alleviated gastrointestinal dysfunctions,motor symptoms,and dopaminergic neuron death in rotenone-challenged mice.16 S rRNA sequencing found that PD-related microbiota alterations induced by rotenone were reversed by FLZ treatment.Remarkably,FLZ administration attenuated intestinal inflammation and gut barrier destruction,which subsequently inhibited systemic inflammation.Eventually,FLZ treatment restored blood-brain barrier structure and suppressed neuroinflammation by inhibiting the activation of astrocytes and microglia in the substantia nigra(SN).Further mechanistic research demonstrated that FLZ treatment suppressed the TLR4/MyD88/NF-κB pathway both in the SN and colon.Collectively,FLZ treatment ameliorates microbiota dysbiosis to protect the PD model via inhibiting TLR4 pathway,which contributes to one of the underlying mechanisms beneath its neuroprotective effects.Our research also supports the importance of microbiota-gut-brain axis in PD pathogenesis,suggesting its potential role as a novel therapeutic target for PD treatment.

ATF4 is directly recruited by TLR4 signaling and positively regulates TLR4-trigged cytokine production in human monocytes

Toll-like receptors （TLRs） are sentinels of the host defense system, which recognize a large number of microbial pathogens. The host defense system may be inefficient or inflammatory diseases may develop if microbial recognition by TLRs and subsequent TLR-triggered cytokine production are deregulated. Activating transcription factor 4 （ATF4）, a member of the ATF/CREB transcription factor family, is an important factor that participates in several pathophysiological processes. In this report, we found that ATF4 is also involved in the TLR-mediated innate immune response, which participates in TLR4 signal transduction and mediates the secretion of a variety of cytokines. We observed that ATF4 is activated and translocates to the nucleus following l ipopolysaccharide （LPS） stimulation via the TLR4-MyD88-dependent pathway. Additionally, a cytokine array assay showed that some key inflammatory cytokines, such as I L-6, I L-8 and RANTES, are positively regulated by ATF4. We also demonstrate that c-Jun directly binds to ATF4, thereby promoting the secretion of inflammatory cytokines. Taken together, these results indicate that ATF4 acts as a positive regulator in TLR4-triggered cytokine production.

电针预处理对心肌缺血再灌注损伤大鼠“内关”穴区Toll样受体4、髓样分化因子88及核转录因子-κB基因表达的影响

目的:观察电针预处理对心肌缺血再灌注损伤(MIRI)大鼠"内关"穴区Toll样受体4(TLR 4)、髓样分化因子88(MyD 88)以及核转录因子-κB(NF-κB)mRNA表达的影响,探讨"内关"抗心肌缺血再灌注的作用与TLR 4/MyD 88/NF-κB信号通路的关系。方法:Wistar大鼠随机分成正常组、正常电针组、假手术组、模型组、电针组和假电针组,每组8只。采用左冠状动脉前降支结扎法制备MIRI大鼠模型,造模前5d开始电针预处理,电针组、正常电针组、假电针组针刺"内关"穴,并给予相应的电针干预,每次30min,每日1次,连续5d。Real-time PCR法检测大鼠"内关"穴区TLR 4、MyD 88和NF-κB mRNA表达水平。结果:与正常组比较,模型组心电图(ECG)-J点显著升高(P<0.01),电针组与模型组和假电针组相比,ECG-J点高度降低(P<0.01)。与正常组相比,模型组大鼠"内关"穴区TLR 4、MyD 88和NF-κB mRNA表达水平显著升高(P<0.01);电针组与模型组、假电针组相比,"内关"穴区TLR 4、MyD 88和NF-κB mRNA的表达水平降低(P<0.05)。结论:电针预处理能降低MIRI大鼠"内关"穴区TLR 4、MyD 88和NF-κB mRNA的表达水平,因此针刺信号的启动-传递-放大可能与TLR 4/MyD 88/NF-κB信号通路有关。

A MyD88-JAK1-STAT1 complex directly induces SOCS-1 expression in macrophages infected with Group A Streptococcus

Some pathogens can use host suppressor of cytokine signaling I （SOCS-1）, an important negative-feedback molecule, as the main mode of immune evasion. Here we found that group A Streptococcus （GAS） is capable of inducing SOCS-1 expression in RAW264.7 and BMDM macrophages. IFN-p plays a role in GAS-induced SOCS-1 expression in macrophages following the induction of cytokine expression by GAS, representing the classical pathway of SOCS-1 expression. However, GAS also induced STAT1 activation and SOCS-1 expression when GAS-infected cells were incubated with anti-IFN-p monoclonal antibody in this study. Moreover, upon comparing TLR4-/- BMDM macrophages with wild-type （WT） cells, we found that TLR4 also plays an essential role in the induction of SOCS-1. MyD88, which is an adaptor protein for TLR4, contributes to STAT1 activation and phosphorylation by forming a complex with Janus kinase 1 （JAK1） and signal transducer and activator of transcription 1 （STAT1） in macrophages. GAS-stimulated expression of STAT1 was severely impaired in MyD88-/- macrophages, whereas expression of JAK1 was unaffected, suggesting that MyD88 was involved in STAT1 expression and phosphorylation. Together, these data demonstrated that in addition to IFN-p signaling and MyD88 complex formation, JAK1 and STAT1 act in a novel pathway to directly induce SOCS-1 expression in GAS-infected macrophages, which may be more conducive to rapid bacterial infection.

Inhibition of miR-873 provides therapeutic benefit in lipopolysaccharide-induced Parkinson disease animal model

OBJECTIVE Neuroinflammation plays a critical role in neurodegenerative disorders,although the inflammation may not the initiating factor.Parkinson disease(PD)is characterized pathologically by the accumulation of alpha synuclein(α-syn)and the loss of the dopamine(DA)neurons in the substantia nigra(SN),which has been reported to be induced by the stereotaxic injection of lipopolysaccharide(LPS)to the SN region in rodents.This study is to investigate the therapeutic benefit of the inhibition of miR-873 in PD.METHODS Rats received the right-unilaterally injection with concentrated LV-sponge or LV-EGFP 3 d before LPS treatment,7 or 14 d after LPS treatment.The animals were tested for rotational behavior with the dopaminergic agonist apomorphine dissolved in sterile saline at 21 d after LPS injection.The regulation of miR-873 on the genes related with cholesterol transport and inflammation was assayed in SH-SY5Y cells and U251 cells.RESULTS TLR4-My D88 signaling pathway was involved the regulation of miR-873 by LPS.The luciferase assay showed that HMGCR,ABCA1 and A20 were down-stream genes of miR-873.The transfection of miR-873 decreased the cholesterol levels in cell membrane,but increased in lysosome in SH-SY5Y cells.Compared with the control SH-SY5Y cells,cholesterol levels were higher in lysosome withα-synuclein overexpression or LPS treatment.The transfection of miR-873 increased theα-syn levels in lysosome in cel s withα-synuclein overexpression.The loss of dopaminergic neuorns induced by LPS was significantly respectively decreased by 22.8%,35.6%and 57% after the inhibition of miR-873 at 3 d before LPS treatment,7 or14 d after LPS treatment.Compared with LPS-treated group,the number of the rotation of rats was decreased by 60.4%,33.5%and 13.2%after the inhibition of miR-873 at 3 d before LPS treatment,7or 14 d after LPS treatment.The inhibition of miR-873 significantly decreased accumulation ofα-syn.The m RNA levels of HMGCR,ABCA1 and A20 in SN were decreased by LPS treatment,which was attenuated by the injection of LV-sponge.CONCLUSION The selective regulation of miR-873 can protect the dopaminergic neurons from the LPS-induced damage.The inhibition of miR-873 can attenuate the relocation of cholesterol in lysosome and the accumulation ofα-syn in neurons induced by LPS via the regulation of HMGCR,ABCA1 and A20.

Discovery of novel aporphine alkaloid derivative as potent TLR2 antagonist reversing macrophage polarization and neutrophil infiltration against acute inflammation

Toll-like receptor 2(TLR2)mediated macrophages regulate the protective immune response to infectious microorganisms,but the aberrant activation of macrophages often leads to pathological inflammation,including tissue damage.In this study,we identified antagonists of TLR2 by screening2100 natural products and subsequently identified Taspine,an aporphine alkaloid,as an excellent candidate.Furthermore,analysis of the 10 steps chemical synthesis route and structural optimization yielded the Taspine derivative SMU-Y6,which has higher activity,better solubility,and improved drug-feasible property.Mechanistic studies and seq-RNA analysis revealed that SMU-Y6 inhibited TLR2 over other TLRs,hindered the formation of TLR2/MyD88 complex,and blocked the downstream NF-κB and MAPK signaling pathway,thus suppressing the release of inflammatory cytokines.SMU-Y6 could stabilize TLR2 and bind to TLR2 protein with a Kdof 0.18μmol/L.Additionally,SMU-Y6 could efficiently reverse the M1 phenotype macrophage polarization,reduce the production of cytokines as well as infiltration of neutrophiles and alleviate the local inflammation in mice with acute paw edema and colitis.Collectively,we reported the first aporphine alkaloid derivative that selectively inhibits TLR2 with high binding affinity and superior drug-feasible property,thus providing an urgently-needed molecular probe and potential drug candidate for inflammatory and autoimmune disease therapy.

Whey protein peptide PEW attenuates hyperuricemia and associated renal inflammation in potassium oxonate and hypoxanthine-induced rat

Pro-Glu-Trp(PEW),a whey protein-derived peptide,has been previously shown in vitro to have antihyperuricemic potential.The current study further evaluated the roles and the underlying mechanism of PEW in the management of hyperuricemia(HUA)in rat induced by potassium oxonate(PO)and hypoxanthine.Results revealed that PEW significantly reduced the levels of uric acid(UA),creatinine(Cr),and blood urea nitrogen(BUN)in serum,and effectively suppressed the activities of xanthine oxidase(XOD)associated with UA synthesis and modulated the expression of organic ion transporters related to UA excretion.Moreover,PEW alleviated UAinduced renal inflammation by regulating oxidative stress,suppressing the level of pro-inflammatory cytokines,and inhibiting the activation of NOD-like receptor family pyrin domain-containing 3(NLRP3)inflammasome and Toll-like receptor 4/myeloid differentiation factor 88/NF-kappaB(TLR4/MyD88/NF-κB)signaling pathway.Taken together,these relults indicated that PEW improved HUA and renal inflammation by inhibiting UA synthesis,promoting renal UA excretion and suppressing NLRP3 inflammasome and TLR4/MyD88/NF-κB signaling pathways.