In vitro and in vivo anti-inflammatory effect of Rhodomyrtus tomentosa methanol extract

Ethnopharmacological relevance

Rhodomyrtus tomentosa (Aiton) Hassk. is a representative Thai medicinal plant traditionally used in South Asian countries to relieve various inflammatory symptoms. However, no systematic studies on its anti-inflammatory activity and mechanisms have been reported.

Materials and methods

The effect of the methanol extract from the leaves of this plant (Rt-ME) on the production of inflammatory mediators [nitric oxide (NO) and prostaglandin E₂ (PGE₂)] and the molecular mechanism of Rt-ME-mediated inhibition, including target enzymes, were studied with RAW264.7, peritoneal macrophage, and HEK293 cells. Additionally, the in vivo anti-inflammatory activity of this extract was evaluated with mouse gastritis and colitis models.

Results

Rt-ME clearly inhibited the production of NO and PGE₂ in lipopolysaccharide (LPS)-activated RAW264.7 cells and peritoneal macrophages in a dose-dependent manner. According to RT-PCR, immunoblotting and immunoprecipitation analyses and a kinase assay with mRNA, whole cell extract, and nucleus lysates from RAW264.7 cells and mice, it was revealed that Rt-ME was capable of suppressing the activation of both nuclear factor (NF)-κB and activator protein (AP)-1 pathways by directly targeting Syk/Src and IRAK1/IRAK4.

Conclusion

Rt-ME could have anti-inflammatory properties by suppressing Syk/Src/NF-kB and IRAK1/IRAK4/AP-1 pathways and will be further developed as a herbal remedy for preventive and/or curative purposes in various inflammatory diseases.     

SS-PEI/核酸纳米复合物的构建分析

目的：构建一种可生物降解的基因载体,并观察其体外转染DNA/siRNA的效率和细胞毒性。方法：采用低分子质量PEI与3,3′-二硫代二丙酸在催化剂作用下合成可降解的PEI衍生物SS-PEI,用红外波谱仪和核磁波谱仪分析其化学结构;动态光散射分析动态光散射（dynamic light scattering,DLS）SS-PEI/DNA和SS-PEI/siRNA的粒径;采用流式细胞技术（FCM）和荧光激活细胞分类术（FACS）分别分析SS-PEI对GFP-DNA和FAM-dsRNA的转染率;通过GFP表达水平分析SS-PEI对GFP质粒和GFP-siRNA的转染效率;采用考马斯蓝法分析SS-PEI/DNA和SS-PEI/siRNA的细胞毒性。结果：红外波谱和核磁波谱与SS-PEI理论波谱一致;DLS结果显示,SS-PEI/DNA复合物粒径为95~175nm,SS-PEI/siRNA平均粒径约200nm。FCM结果显示,SS-PEI对DNA的最大转染率为（25.2±2.3）%,稍低于HWPEI组的（33.8±3.1）%;SS-PEI/GFP-DNA转染后GFP的表达水平与HWPEI转染组接近〔（150±7）FI（A.U.）/mg蛋白vs（168±18）FI（A.U.）/mg蛋白〕,差异无统计学意义,t=1.62,P=0.18;细胞毒性分析显示,SS-PEI/DNA组细胞活力（89±5.2）%,显著高于HWPEI/DNA组的（70±4.9）%,差异有统计学意义,t=4.61,P=0.001。FACS结果显示,SS-PEI对FAM-dsRNA的转染率为（86.5±2.5）%;SS-PEI转染GFP-siRNA,靶基因GFP被显著敲除,相对表达水平为（42±3.5）FI（A.U.）/mg蛋白,与对照组的（79±10.8）FI（A.U.）/mg蛋白相比差异有统计学意义,t=5.64,P=0.004。结论：SS-PEI的合成可明显提高装载核酸的效率,具有低毒和高效等特点。     

Inhibition of cancer stem cell-like properties and reduced chemoradioresistance of glioblastoma using microRNA145 with cationic polyurethane-short branch PEI

Glioblastomas (GBMs) are the most common primary brain tumors with poor prognosis. CD133 has been considered a putative marker of cancer stem cells (CSCs) in malignant cancers, including GBMs. MicroRNAs (miRNAs), highly conserved small RNA molecules, may target oncogenes and have potential as a therapeutic strategy against cancer. However, the role of miRNAs in GBM-associated CSCs remains mostly unclear. In this study, our miRNA/mRNA-microarray and RT-PCR analysis showed that the expression of miR145 (a tumor-suppressive miRNA) is inversely correlated with the levels of Oct4 and Sox2 in GBM-CD133⁺ cells and malignant glioma specimens. We demonstrated that miR145 negatively regulates GBM tumorigenesis by targeting Oct4 and Sox2 in GBM-CD133⁺. Using polyurethane-short branch polyethylenimine (PU-PEI) as a therapeutic-delivery vehicle, PU-PEI-mediated miR145 delivery to GBM-CD133⁺ significantly inhibited their tumorigenic and CSC-like abilities and facilitated their differentiation into CD133⁻-non-CSCs. Furthermore, PU-PEI-miR145-treated GBM-CD133⁺ effectively suppressed the expression of drug-resistance and anti-apoptotic genes and increased the sensitivity of the cells to radiation and temozolomide. Finally, the in vivo delivery of PU-PEI-miR145 alone significantly suppressed tumorigenesis with stemness, and synergistically improved the survival rate when used in combination with radiotherapy and temozolomide in orthotopic GBM-CD133⁺-transplanted immunocompromised mice. Therefore, PU-PEI-miR145 is a novel therapeutic approach for malignant brain tumors.     

聚乙烯亚胺介导miR-2861模拟物转染MC3T3-E1细胞的体外成骨分化

目的：通过非病毒载体聚乙烯亚胺（PEI）介导miRNA-2861（miR-2861）模拟物转染MC3T3-E1细胞系,探讨miR-2861/PEI复合物在前成骨细胞中的转染效率及其对细胞增殖和成骨向分化的影响。方法：将适量的PEI分别与miR-2861和阴性对照（NC）以元素N/P=10的比例混合形成基因/载体复合物。将miR-2861/PEI复合物作为实验组,NC/PEI复合物作为阴性对照组以排除人工合成的双链基因对成骨作用的干扰。采用MTT法筛选PEI复合miR-2861模拟物的最佳使用浓度;应用荧光成像和茎环法RT-PCR技术分别检测10、30、50和100 nmol·L^-1 miR/PEI复合物对MC3T3细胞的瞬时转染效率和miR-2861的表达情况;采用qRT-PCR技术和茜素红染色检测用选定浓度瞬时转染miR-2861/PEI复合物作用下MC3T3细胞的成骨能力。结果：与空白对照组比较,100 nmol·L^-1 miR-2861/PEI复合物作用72h时MC3T3细胞增殖率明显下降（P<0.05）。随转染浓度增加,miR-2861/PEI复合物在MC3T3细胞中的转染效率逐渐升高。茜素红染色及定量分析,实验组诱导21 d后出现较多的钙盐沉积结节,而空白对照组和阴性对照组均较少。结论：以PEI作为载体可使miR-2861模拟物有效转染MC3T3-E1细胞并在细胞中高表达,miR-2861模拟物具有一定的促MC3T3-E1细胞成骨向分化的作用。     

Receptor-mediated targeted drug delivery systems for treatment of inflammatory bowel disease: Opportunities and emerging strategies

Inflammatory bowel disease (IBD) is a chronic intestinal disease with painful clinical manifestations and high risks of cancerization. With no curative therapy for IBD at present, the development of effective therapeutics is highly advocated. Drug delivery systems have been extensively studied to transmit therapeutics to inflamed colon sites through the enhanced permeability and retention (EPR) effect caused by the inflammation. However, the drug still could not achieve effective concentration value that merely utilized on EPR effect and display better therapeutic efficacy in the inflamed region because of nontargeted drug release. Substantial researches have shown that some specific receptors and cell adhesion molecules highly expresses on the surface of colonic endothelial and/or immune cells when IBD occurs, ligand-modified drug delivery systems targeting such receptors and cell adhesion molecules can specifically deliver drug into inflamed sites and obtain great curative effects. This review introduces the overexpressed receptors and cell adhesion molecules in inflamed colon sites and retrospects the drug delivery systems functionalized by related ligands. Finally, challenges and future directions in this field are presented to advance the development of the receptor-mediated targeted drug delivery systems for the therapy of IBD.     

Nischarin-siRNA delivered by polyethylenimine-alginate nanoparticles accelerates motor function recovery after spinal cord injury

A previous study by our group found that inhibition of nischarin promotes neurite outgrowth and neuronal regeneration in Neuro-2 a cells and primary cortical neurons.In recent years,more and more studies have shown that nanomaterials have good prospects in treatment of spinal cord injury.We proposed that small interfering RNA targeting nischarin(Nis-si RNA) delivered by polyethyleneimine-alginate(PEIALG) nanoparticles promoted motor function recovery in rats with spinal cord injury.Direct microinjection of 5 μL PEI-ALG/Nis-si RNA into the spinal cord lesion area of spinal cord injury rats was performed.From day 7 after surgery,Basso,Beattie and Bresnahan score was significantly higher in rats from the PEI-ALG/Nis-si RNA group compared with the spinal cord injury group and PEI-ALG/Control-si RNA group.On day 21 after injection,hematoxylin-eosin staining showed that the necrotic area was reduced in the PEI-ALG/Nis-si RNA group.Immunohistochemistry and western blot assay results confirmed successful inhibition of nischarin expression and increased protein expression of growth-associated protein-43 in the PEI-ALG/Nis-si RNA group.These findings suggest that a complex of PEI-ALG nanoparticles and Nis-si RNA effectively suppresses nischarin expression,induces expression of growth-associated protein-43,and accelerates motor function recovery after spinal cord injury.     

Salmonella flagella confer anti-tumor immunological effect via activating Flagellin/TLR5 signalling within tumor microenvironment

Salmonellamediated cancer therapy has achieved remarkable anti-tumor effects in experimental animal models, but the detailed mechanism remains unsolved. In this report, the active involvement of the host immune response in this process was confirmed by comparing the tumor-suppressive effects of Salmonella in immunocompetent and immunodeficient mice bearing melanoma allografts. Since flagella are key inducers of the host immune response during bacterial infection, flagella were genetically disrupted to analyse their involvement in Salmonella-mediated cancer therapy. The results showed that flagellum-deficient strains failed to induce significant anti-tumor effects, even when more bacteria were administered to offset the difference in invasion efficiency. Flagella mainly activate immune cells via Flagellin/Toll-like receptor 5 (TLR5) signalling pathway. Indeed, we showed that exogenous activation of TLR5 signalling by recombinant Flagellin and exogenous expression of TLR5 both enhanced the therapeutic efficacy of flagellum-deficient Salmonella against melanoma. Our study highlighted the therapeutic value of the interaction between Salmonella and the host immune response through Flagellin/TLR5 signalling pathway during Salmonella-mediated cancer therapy, thereby suggesting the potential application of TLR5 agonists in the cancer immune therapy.     

芯壳型PEI／PLGA同轴电纺纤维的制备及其相关理化性能研究

目的：利用同轴静电纺丝技术制备纳米级聚乳酸-羟基乙酸共聚物（PLGA）与聚乙烯亚胺（PEI）芯壳型复合纤维，评价其相关理化性能。方法：运用同轴静电纺丝法制备壳层为PLGA，芯层为PEI的电纺纤维膜。扫描电子显微镜观察纤维膜表面形貌、激光共聚焦显微镜检测纤维同轴结构、接触角测量仪测定接触角、万能试验机测量纤维力学性能。结果：所制备的同轴芯壳型PEI/PLGA电纺纤维表面光滑、分布均匀、直径范围175～1076 nm，激光共聚焦显微镜下可见清晰的芯壳结构，接触角为72．45±2．02°，拉伸强度（3．65±0．35）Mpa、弹性模量9．0±1．70。结论：作为一种新型支架材料，采用同轴静电纺丝法可以制备PEI/PLGA芯壳结构的电纺纤维在组织工程领域有进一步的应用前景。     

A Novel Non-Viral Vector for DNA Delivery Based on Low Molecular Weight,Branched Polyethylenimine: Effect of Molecular Weight on Transfection Efficiency and Cytotoxicity

Purpose. Low molecular weight branched polyethylenimine (LMW-PEI) was synthesized and studied as a DNA carrier for gene delivery with regard to physico-chemical properties, cytotoxicity, and transfection efficiency. Methods. The architecture of LMW-PEI, synthesized by acid catalyzed ring-opening polymerization of aziridine was characterized by size exclusion chromatography in combination with laser light scattering and ¹³C-NMR-spectroscopy. In vitro cytotoxic effects were quantified by LDH and MTT assay and visualized by transmission electron microscopy. The potential for transgene expression was monitored in ECV304 cells using luciferase driven by a SV40 promoter as reporter gene system. Results. LMW-PEI (Mw 11900 D) with a low degree of branching was synthesized as a DNA carrier for gene delivery. In contrast to high molecular weight polyethylenimines (HMW-PEI; Mw l616OOO D), the polymer described here showed a different degree of branching and was less cytotoxic in a broad range of concentrations. As demonstrated by transmission electron microscopy the LMW-PEI formed only small aggregates which were efficiently taken up by different cells in the presence of serum, most likely by an endocytic pathway. LMW-PEI yielded transfection efficiencies measured via expression of the reporter gene luciferase which were up to two orders of magnitude higher than those obtained with HMW-PEI. The reporter gene expression was concentration dependent, but in contrast to lipofection independent of serum addition. Conclusions. The LMW-PEI described here is a new, highly efficient, and non-cytotoxic vector with a favorable efficiency/toxicity profile for gene therapeutic applications.     

Identification of CD4+ and CD8+ T cell epitopes of woodchuck hepatitis virus core and surface antigens in BALB/c mice

A therapeutic vaccine against chronic hepatitis B virus (HBV) infection requires the development of a strong and multispecific Th1 cell immune response. Woodchucks chronically infected with the woodchuck hepatitis virus (WHV) closely resemble HBV infection and represent the best animal model for this hepadnavirus-induced disease. Using the BIMAS “HLA Peptide Binding Predictions” program, we have identified and further characterized novel H-2^d-restricted CD8+ epitopes within the WHV core (peptides C#12–21, C#18–32, C#19–27, C#61–69) and surface antigens (peptides preS2#10–18, preS2#27–35, S#76–84, S#133–140 and S#257–265), respectively. These peptides bind to H-2^d with high efficiency and upon immunization of mice with peptide and Freund's adjuvant they induce the development of IFN-γ producing T cells. More importantly, WHV core peptides C#19–27 and C#61–69 and WHV surface peptides S#133–140 and S#257–265 were also recognized by CD8+ T cells after immunization of mice with DNA/PEI nanoparticles. Direct stimulation of splenocytes obtained from such DNA-immunized mice with peptides C#18–32, S#76–84, and S#257–265 resulted in significant production of IFN-γ. Thus, we have identified T cell determinants in mice from WHV core and surface antigens that have important value for designing and evaluating an effective vaccine against hepadnavirus infection.