Phycocyanin attenuates X-ray-induced pulmonary inflammation via the TLR2-MyD88-NF-κB signaling pathway

Phycocyanin (PC), a natural algal protein, is reported for having anti-oxidant and antiinfl ammatory properties. We investigated its ability to attenuate lung infl ammation in mice subjected to X-ray radiation. Male C57BL/6 mice were assigned to the control, total body irradiation, PC pretreatment, and PC treatment groups. Mice in the PC pretreatment group were gavaged with 200 mg/kg PC for 7 consecutive days before irradiation, and those in the PC treatment group were gavaged with 200 mg/kg PC for 7 consecutive days after irradiation. Lungs were collected on Day 7 after irradiation exposure. Hematoxylin and eosin staining of mouse lung sections showed considerable infl ammation damage 7 days after irradiation compared with the control lung but a reduction in pathological injury in the PC treatment group. Pretreatment or treatment with PC signifi cantly decreased levels of interleukin-6 and tumor necrosis factor-α in the lung, and also increased the relative mRNA expression of superoxide dismutase and glutathione. In vivo, PC signifi cantly reduced the expression of Toll-like receptor TLR2, myeloid diff erentiation primary response Myd88, and nuclear factor NF-κB, at both the transcriptional and translation level. Taken together, these data indicated that PC attenuated lung infl ammatory damage induced by radiation by blocking the TLR2- MyD88-NF-κB signaling pathway. Therefore, PC could be a protective agent against radiation-induced infl ammatory damage in normal tissues.

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.

Neuroprotective effect of Angiopep-2 peptide modified scutellarin-loaded PEGylated PAMAM dendrimer nanoparticles on ischemic stroke by modulating the Toll-like receptors-dependent MyD88/IKK/NF-κB signaling pathway

OBJECTIVE The greatest challenge in chemotherapy of ischemic stroke is the construction a suitable delivery system to overcome the poor physicochemical properties of drug and its low permeability across the blood brain barrier(BBB).METHODS In the present study,dendrimer,polyamidoamine(PAMAM),was synthesized as the nano-drug carriers.Angiopep-2,which has been proved excellent ability to cross the BBB,was exploited as the targeting ligand to conjugate PAMAM via bifunctional polyethylene glycol(PEG).Then scutellarin(STA)was encapsulated into the functionalized nanoparticles(NPs)to formulate Angiopep-2 modified STA-loaded PEG-PAMAM NPs.Ischemic stroke model was established to evaluate the treatment efficacy and protective mechanism of Angiopep-2-STA-PEG-PAMAM NPs.RESULTS The pharmacokinetics and biodistribu-tion demonstrated that Angiopep-2-STA-PEG-PAMAM NPs exhibited significantly higher plasma concentration from 1 h to 10 h after intravenous administration and improve accumulation in brain(4.7-fold)compared with STA solution.Moreover,prolonged elimination half-life(4.8-fold)and lower clearance(3.4-fold)were observed.The brain uptake study of 6-coumarin confirmed that Angiopep-2-PEG-PAMAM NPs possessed better brain targeting efficacy(3.2-fold)than PEG-PAMAM NPs.Angiopep-2-STA-PEG-PAMAM NPs obviously ameliorated infarct volume,neurological deficit,histopathological severity and neuronal apoptosis.In addition,Angiopep-2-STA-PEG-PAMAM NPs markedly inhibited the calcium content and the levels of IL-12p40,IL-13,IL-17 and IL-23.Furthermore,Angiopep-2-STA-PEG-PAMAM NPs significantly decreased the m RNA and protein expressions of HMGB1,TLR2,TLR4,TLR5,My D88,TRIF,TRAM,IRAK-4,TRAF6,IкBα,IKKβand NF-кBp65.CONCLUSION The results suggested that Angiopep-2modified scutellarin-loaded PEG-PAMAM nanocarriers possessed remarkable neuroprotective effects on ischemic stroke through modulation of inflammatory cascades and HMGB1/TLRs/MyD 88-induced NF-κB activation pathways.

β-淀粉样蛋白1-42寡聚体对BV2小胶质细胞炎症反应的影响及机制研究

目的:探讨β-淀粉样蛋白1-42寡聚体(amyloidβ-protein 1-42 oligomer,oAβ)对BV2小胶质细胞炎症反应的影响及可能的机制。方法:制备oAβ,采用不同浓度(0、0.5、1、5、10、20μmol/L)的oAβ孵育BV2小胶质细胞24 h后,用倒置相差显微镜观察细胞形态变化;用CCK-8法检测BV2小胶质细胞活力;用ELISA法检测细胞培养上清液中肿瘤坏死因子α(tumor necrosis factorα,TNF-α)、白细胞介素6(interleukin-6,IL-6)、IL-4和IL-10的分泌水平。随后将BV2小胶质细胞分成对照组、模型组和拮抗剂组,模型组选取浓度为5μmol/L的oAβ处理BV2小胶质细胞,拮抗剂组在模型组基础上加10μmol/L Toll样受体1(Toll-like receptor 1,TLR1)/TLR2拮抗剂CU-CPT22作用于细胞,应用RT-qPCR和Western blot检测3组细胞TLR1、TLR2、髓样分化因子88(myeloid differentiation factor 88,MyD88)的mRNA和蛋白表达,用ELISA检测细胞培养上清液中TNF-α、IL-6、IL-4和IL-10的分泌水平。结果:BV2小胶质细胞的活力随着oAβ浓度的增加而降低,TNF-α和IL-6分泌水平随oAβ浓度的增加而升高,IL-4和IL-10分泌水平随oAβ浓度的增加而降低,且与0μmol/L oAβ组比较差异均有统计学意义(P<0.05)。与对照组相比,模型组TLR1、TLR2和MyD88的mRNA及蛋白表达水平均显著升高(P<0.01),TNF-α和IL-6分泌水平显著升高(P<0.01),IL-4和IL-10分泌水平显著降低(P<0.01);与模型组相比,拮抗剂组TLR1、TLR2及MyD88 mRNA和蛋白表达均显著降低(P<0.05),TNF-α和IL-6分泌水平显著降低(P<0.01),IL-4和IL-10分泌水平无显著变化(P>0.05)。结论:不同浓度的oAβ刺激BV2小胶质细胞后均出现了炎症反应,且oAβ呈浓度依赖性的升高了促炎细胞因子TNF-α和IL-6的表达水平,降低了抗炎细胞因子IL-4和IL-10的表达水平;oAβ可能通过TLR1/2-MyD88信号通路诱导BV2小胶质细胞活化,进而上调其促炎介质的水平。

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.

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.