Dahuang Zhechong pill attenuates CCl4-induced rat liver fibrosis via the PI3K-Akt signaling pathway

It is well characterized that activated hepatic stellate cells (HSCs) exert critical functions in accelerating the progression of liver fibrosis. Previous studies have indicated that Dahuang Zhechong pill (DHZCP), a traditional Chinese herbal medicine, is capable of inactivating HSCs and thus attenuate the formation of liver fibrosis in rats. However, pharmacological mechanisms of DHZCP in alleviating liver fibrosis remain unclear. This study aims to investigate the antifibrotic role of DHZCP through inhibiting the phosphatidylinositol 3-kinase (PI3K)-protein kinase B (Akt) pathway. DHZCP was found to significantly suppresses extracellular matrix formation and immune cell infiltration, thus alleviating liver fibrosis symptoms in the in vivo model. Moreover, DHZCP reduced serum levels of transforming growth factor β1 and tumor necrosis factor-α in rats with liver fibrosis. DHZCP treatment remarkably downregulated protein levels of PI3K and phosphorylated Akt, as well as fibrosis markers. In vitro experiments further demonstrated that DHZCP markedly suppressed HSCs proliferation by downregulating PI3K/Akt, which exerted a synergistic effect with the PI3K inhibitor LY294002. To sum up, our results confirmed that DHZCP exerted an antifibrotic effect in the animal model through inactivating the PI3K/Akt pathway, thus protecting rats from liver injury.     

Inhibition of methicillin-resistant Staphylococcus aureus (MRSA) biofilm by cationic poly (D,L-lactide-co-glycolide) nanoparticles

Abstract

The emergent need for new treatment methods for multi-drug resistant pathogens such as methicillin-resistant Staphylococcus aureus (MRSA) has focused attention on novel potential tools like nanoparticles (NPs). In the present study, a drug-free cationic nanoparticles (CNPs) system was developed and its anti-MRSA effects were firstly investigated. The results showed that CNPs (261.7?nm, 26.1?mv) showed time- and concentration-dependent activity against MRSA growth, killing ～ 90% of planktonic bacterial cells in 3?h at 400?μg ml^?1, and completely inhibiting biofilm formation at 1000?μg ml^?1. Moreover, CNPs at 400?μg ml^?1 reduced the minimum inhibitory concentration (MIC) of vancomycin on inhibition of planktonic MRSA growth (～ 25%) and biofilm formation (～ 50%). The CNPs–bacteria interaction force was up to 22 nN. Overall, these data suggest that CNPs have a good potential in clinical applications for the prevention and treatment of MRSA infection.     

A novel compound derived from danshensu inhibits apoptosis via upregulation of heme oxygenase-1 expression in SH-SY5Y cells

Background

Heme oxygenase-1 (HO-1) has potential anti-apoptotic properties. A novel compound [4-(2-acetoxy-3-((R)-3-(benzylthio)-1-methoxy-1-oxopropan-2- ylamino)-3-oxopropyl)-1,2-phenylene diacetate (DSC)] was synthesized by joining danshensu and cysteine through an appropriate linker. This study investigated if the cytoprotective properties of DSC involved the induction of HO-1.

Methods

We evaluated the cytoprotective effects of DSC on H₂O₂-induced cell damage, apoptosis, intracellular and mitochondrial reactive oxygen species (ROS) production, mitochondrial membrane potential (ΔΨ_m) loss, and apoptosis-related proteins expression and its underlying mechanisms.

Results

DSC concentration-dependently attenuated cell death, lactate dehydrogenase release, intracellular and mitochondrial ROS production, and ΔΨ_m collapse, modulated apoptosis-related proteins (Bcl-2, Bax, caspase-3, p53, and cleaved PARP) expression, and inhibited phosphorylation of extracellular signal-regulated kinase 1/2 in SH-SY5Y cells induced by H₂O₂. In addition, DSC concentration-dependently induced HO-1 expression associated with nuclear translocation of nuclear factor-erythroid 2 related factor 2 (Nrf-2), while the effect of DSC was inhibited by a phosphoinositide 3-kinase (PI3K) inhibitor LY294002. Furthermore, the protective effect of DSC on H₂O₂-induced cell death was abolished by HO-1 inhibitor ZnPP, but was mimicked by carbon monoxide-releasing moiety CORM-3 or HO-1 by-product bilirubin. Finally, DSC inhibited H₂O₂-induced changes of Bcl-2, Bax, and caspase-3 expression, and all of these effects were reversed by HO-1 silencing.

Conclusions

Induction of HO-1 may be, at least in part, responsible for the anti-apoptotic property of DSC, an effect that involved the activation of PI3K/Akt/Nrf-2 axis.

General significance

DSC might have the potential for beneficial therapeutic interventions for neurodegenerative diseases.     

Auxin distribution is differentially affected by nitrate in roots of two rice cultivars differing in responsiveness to nitrogen

Background and Aims

Although ammonium (NH₄⁺) is the preferred form of nitrogen over nitrate (NO₃⁻) for rice (Oryza sativa), lateral root (LR) growth in roots is enhanced by partial NO₃⁻ nutrition (PNN). The roles of auxin distribution and polar transport in LR formation in response to localized NO₃⁻ availability are not known.

Methods

Time-course studies in a split-root experimental system were used to investigate LR development patterns, auxin distribution, polar auxin transport and expression of auxin transporter genes in LR zones in response to localized PNN in ‘Nanguang’ and ‘Elio’ rice cultivars, which show high and low responsiveness to NO₃⁻, respectively. Patterns of auxin distribution and the effects of polar auxin transport inhibitors were also examined in DR5::GUS transgenic plants.

Key Results

Initiation of LRs was enhanced by PNN after 7 d cultivation in ‘Nanguang’ but not in ‘Elio’. Auxin concentration in the roots of ‘Nanguang’ increased by approx. 24 % after 5 d cultivation with PNN compared with NH₄⁺ as the sole nitrogen source, but no difference was observed in ‘Elio’. More auxin flux into the LR zone in ‘Nanguang’ roots was observed in response to NO₃⁻ compared with NH₄⁺ treatment. A greater number of auxin influx and efflux transporter genes showed increased expression in the LR zone in response to PNN in ‘Nanguang’ than in ‘Elio’.

Conclusions

The results indicate that higher NO₃⁻ responsiveness is associated with greater auxin accumulation in the LR zone and is strongly related to a higher rate of LR initiation in the cultivar ‘Nanguang’.     

Tagging SNPs in the ERCC4 gene are associated with gastric cancer risk

ERCC4 plays an essential role in the nucleotide excision repair (NER) pathway, which is involved in the removal of a wide variety of DNA lesions. To determine whether the ERCC4 tagging SNPs (tSNPs) are associated with risk of gastric cancer, we conducted a hospital-based case-control study of 350 cases and 468 cancer-free controls. In the logistic regression (LR) analysis, we found a significantly decreased risk of gastric cancer associated with the rs744154 GC/CC genotypes [adjusted odds ratio (OR) = 0.56, 95% confidence interval (CI) = 0.42–0.75, false discovery rate (FDR) P = 0.003] compared with the wild-type GG genotype. Haplotype-based association study revealed that the CGC haplotype that containing the rs744154 C allele can decrease the risk of gastric cancer compared with the most common haplotype GGT (adjusted OR = 0.61, 95% CI = 0.46–0.81). Using the multifactor dimensionality reduction (MDR) analysis, we identified that the SNP rs744154 and smoking status were the best two predictive factors for gastric cancer with a testing accuracy of 55.76% and a perfect cross-validation consistency (CVC) of 10 (P = 0.001). Furthermore, the smokers with the rs744154 GC/CC genotypes showed a decreased risk of gastric cancer (adjusted OR = 0.55, 95% CI = 0.35–0.85) compared with the smokers with the GG genotype using multivariate LR analysis. The above findings consistently suggested that genetic variants in the ERCC4 gene may play a protective role in the etiology of gastric cancer, even in the smokers.     

全反式维甲酸协同DAPT抑制胶质瘤干细胞的自我更新

前期研究脑表明,脑胶质瘤干细胞（glioma stem cells,GSCs）是胶质瘤发生和发展的重要因素,探索靶向干预GSCs生长有可能成为脑胶质瘤治疗的有效途径之一。该研究旨在阐明两种药物ATRA和Y-分泌酶抑制剂DAPT协同抑制GSCs自我更新的生物学效应。通过用台盼蓝排染法、克隆球形成试验和免疫印迹分析了两种药物的单独使用或联用对GSC样细胞PGCl和PGC2生长、成球能力和自我更新以及干细胞标志物表达的影响。结果发现,单独使用ATRA对PGCl生长有一定的抑制作用,而对PGC2生长几乎没有影响;DAPT对PGCs的生长抑制作用明显强于ATRA。高浓度ATRA（80μmol/L）能诱导PGCs的分化,降低PGCs成球大小,且成球效率降至5％～8％,而正常对照组为32％～35％;同样,DAPT（40μmol／L）也能降低PGCs成球大小,且成球效率降至2％～3％;低浓度ATRA（20μmol／L）和DAPT（5gmol／L）对PGCs自我更新能力和干性没有明显影响,而联合使用后其明显降低PGCs的成球大小,且成球效率降至3％～5％,促进细胞凋亡,并且明显抑制了干细胞标志物Nestin、CDl33、Sox2、Oct4的表达,提高了分化标志物GFAP的表达。该研究证明了低浓度的ATRA和DAPT能协同抑制脑胶质瘤干细胞PGCs的自我更新。研究结果将为脑胶质瘤的临床研究提供实验依据。     

A Novel Integrated Method Tor Large-scale Detection,Identification, and Quantification of Widely Targeted Metabolites： Application in the Study of Rice Metabolomics

Liquid chromatography-mass spectrometry （LC-MS）-based metabolomics has been facilitated by the con- struction of MSz spectral tag （MS2T） library from the total scan ESI MS/MS data, and the development of widely targeted metabolomics method using MS/MS data gathered from authentic standards. In this report, a novel strategy called step- wise multiple ion monitoring-enhanced product ions （stepwise MIM-EPI） was developed to construct the MS2T library, in which stepwise MIM was used as survey scans to trigger the acquisition of EPI. A total number of 698 （almost） non- redundant metabolites with MS2 spectra were obtained, of which 135 metabolites were identified/annotated. Integrating the data gathered from our MS2T library and other available multiple reaction monitoring （MRM） information, a widely targeted metabolomics method was developed to quantify 277 metabolites, including some phytohormones. Evaluation of the dehydration responses and natural variations of these metabolites in rice leaf not only suggested the coordinated regulation of abscisic acid （ABA） with metabolites such as serotonin derivative（s）, polyamine conjugates under drought stress, but also revealed some C-glycosylated flavones as the potential markers for the discrimination of indica and japonica rice subspecies. The new MS2T library construction and widely targeted metabolomics strategy could be used as a tool for rice functional genomics.