Mechanistic study of the anti‐cancer effect of Gynostemma pentaphyllum saponins in the ApcMin/+ mouse model

Gynostemma pentaphyllum saponins (GpS) have been shown to have anti‐cancer activity. However, the underlying mechanisms remain unclear. In this study, we used the Apc^Min/+ colorectal cancer (CRC) mouse model to investigate the anti‐cancer effect of GpS and we demonstrated that GpS treatment could significantly reduce the number and size of intestinal polyps in Apc^Min/+ mice. In order to identify the potential targets and mechanisms involved, a comparative proteomics analysis was performed and 40 differentially expressed proteins after GpS treatment were identified. Bioinformatics analyses suggested a majority of these proteins were involved in processes related to cellular redox homeostasis, and predicted Raf‐1 as a potential target of GpS. The upregulation of two proteins known to be involved in redox homeostasis, peroxiredoxin‐1 (Prdx1) and peroxiredoxin‐2 (Prdx2), and the downregulation of Raf‐1 were validated using Western blot analysis. After further investigation of the associated signaling networks, we postulated that the anti‐cancer effect of GpS was mediated through the upregulation of Prdx1 and Prdx2, suppression of Ras, RAF/MEK/ERK/STAT, PI3K/AKT/mTOR signaling and modulation of JNK/p38 MAPK signaling. We also examined the potential combinatorial effect of GpS with the chemotherapeutic 5‐fluorouracil (5‐FU) and found that GpS could enhance the anti‐cancer efficacy of 5‐FU, further suppressing the number of polyps in Apc^Min/+ mice. Our findings highlight the potential of GpS as an anti‐cancer agent, the potential mechanisms of its anti‐cancer activities, and its effect as an adjuvant of 5‐FU in the chemotherapy of CRC.     

Maternal Inheritance of a Single Somatic Animal Cell Displayed by the Bacteriocyte in the Whitefly Bemisia tabaci

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Pseudorabies virus tegument protein UL13 recruits RNF5 to inhibit STING-mediated antiviral immunity

Pseudorabies virus (PRV) has evolved various immune evasion mechanisms that target host antiviral immune responses. However, it is unclear whether and how PRV encoded proteins modulate the cGAS-STING axis for immune evasion. Here, we show that PRV tegument protein UL13 inhibits STING-mediated antiviral signaling via regulation of STING stability. Mechanistically, UL13 interacts with the CDN domain of STING and recruits the E3 ligase RING-finger protein 5 (RNF5) to promote K27-/K29-linked ubiquitination and degradation of STING. Consequently, deficiency of RNF5 enhances host antiviral immune responses triggered by PRV infection. In addition, mutant PRV lacking UL13 impaired in antagonism of STING-mediated production of type I IFNs and shows attenuated pathogenicity in mice. Our findings suggest that PRV UL13 functions as an antagonist of IFN signaling via a novel mechanism by targeting STING to persistently evade host antiviral responses.     

Discovery of a small-molecule inhibitor of the TRIP8b–HCN interaction with efficacy in neurons

Major depressive disorder is a critical public health problem with a lifetime prevalence of nearly 17% in the United States. One potential therapeutic target is the interaction between hyperpolarization-activated cyclic nucleotide–gated (HCN) channels and an auxiliary subunit of the channel named tetratricopeptide repeat–containing Rab8b-interacting protein (TRIP8b). HCN channels regulate neuronal excitability in the mammalian hippocampus, and recent work has established that antagonizing HCN function rescues cognitive impairment caused by chronic stress. Here, we utilize a high-throughput virtual screen to find small molecules capable of disrupting the TRIP8b–HCN interaction. We found that the hit compound NUCC-0200590 disrupts the TRIP8b–HCN interaction in vitro and in vivo. These results provide a compelling strategy for developing new small molecules capable of disrupting the TRIP8b–HCN interaction.     

Mutational analyses of the influenza A virus polymerase subunit PA reveal distinct functions related and unrelated to RNA polymerase activity

Influenza A viral polymerase is a heterotrimeric complex that consists of PA, PB1, and PB2 subunits. We previously reported that a di-codon substitution mutation (G507A-R508A), denoted J10, in the C-terminal half of PA had no apparent effect on viral RNA synthesis but prevented infectious virus production, indicating that PA may have a novel role independent of its polymerase activity. To further examine the roles of PA in the viral life cycle, we have now generated and characterized additional mutations in regions flanking the J10 site from residues 497 to 518. All tested di-codon mutations completely abolished or significantly reduced viral infectivity, but they did so through disparate mechanisms. Several showed effects resembling those of J10, in that the mutant polymerase supported normal levels of viral RNA synthesis but nonetheless failed to generate infectious viral particles. Others eliminated polymerase activity, in most cases by perturbing the normal nuclear localization of PA protein in cells. We also engineered single-codon mutations that were predicted to pack near the J10 site in the crystal structure of PA, and found that altering residues K378 or D478 each produced a J10-like phenotype. In further studies of J10 itself, we found that this mutation does not affect the formation and release of virion-like particles per se, but instead impairs the ability of those particles to incorporate each of the eight essential RNA segments (vRNAs) that make up the viral genome. Taken together, our analysis identifies mutations in the C-terminal region of PA that differentially affect at least three distinct activities: protein nuclear localization, viral RNA synthesis, and a trans-acting function that is required for efficient packaging of all eight vRNAs.     

Neuroprotective effects of iron chelator Desferal on dopaminergic neurons in the substantia nigra of rats with iron-overload

The aim of the present study was to investigate whether the iron chelator Desferal prevents the degeneration of dopaminergic neurons in the substantia nigra (SN) induced by iron-overload in rats. Using fast cyclic voltammetry, tyrosine hydroxylase (TH) immunohistochemistry, Perls' iron staining, and high-performance liquid chromatography-electrochemical detection, we measured the degeneration of dopaminergic neurons and increased iron content in the SN of rats overloaded with iron dextran and assessed the effects of treatment with Desferal. The results showed that iron dextran overload increased the iron content in the SN, decreased dopamine release and content, and reduced the numbers of TH-immunoreactive neurons. Treatment with Desferal prevented the increased iron content in the SN. As a result, dopamine release and content remained at almost normal levels, while the numbers of TH-immunoreactive neurons remained at control values. This study suggests that the iron chelator Desferal is neuroprotective against iron-overload, so iron chelators that can cross the blood-brain barrier may have the potential to treat cases where abnormal iron accumulation in the brain is associated with the degenerative processes, as in Parkinson's disease.     

桃金娘叶的化学成分研究

为了解桃金娘[Rhodomyrtus tomentosa(Ait.) Hassk.]的化学成分,从其叶的醇提物中分离得到10个化合物,经波谱分析分别鉴定为羽扇豆醇(1)、杨梅素-3-O-α-L-鼠李糖苷(2)、rhodomyrtone (3)、4,8,9,10-四羟基-2,3,7-三甲氧基蒽醌-6-O-β-D-葡萄糖苷(4)、豆甾醇(5)、山奈酚-3-O-α-L-呋喃阿拉伯糖苷(6)、杨梅素(7)、23-羟基委陵菜酸(8)、2α,3β,19α,23-四羟基乌苏-12-烯-28-酸28-O-β-D-吡喃葡萄糖苷(9)和laricitrin (10)。其中化合物5~10均为首次从桃金娘中分离得到。化合物3对金黄色葡萄球菌、蜡样芽孢杆菌和枯草芽孢杆菌表现出显著的抗菌活性(MIC=0.78μg mL–1)。     

Variants in the APOC3 promoter insulin responsive element modulate insulin secretion and lipids in middle-aged men

Variation in the insulin responsive element (IRE) of the APOC3 promoter has been shown to be associated with insulin and glucose concentrations after an oral glucose tolerance test (OGTT) in young healthy men. We evaluated two variants in the IRE (-455T>C and -482C>T) in the Ely study, a prospective cohort study of middle-aged men (n=223) and women (n=279), to determine if the effect of these variants on glucose homeostasis could be explained by altered nonesterified fatty acid (NEFA) levels and if these effects are modulated by age and gender. Both variants had significant effects on the 30-min insulin incremental response in men alone (-482C>T, P=0.007; -455T>C, P=0.0155), with rare allele homozygotes having a 33.3% and 23.3% lower insulin increment as compared to common allele homozygotes, respectively. Thirty-minute NEFA concentrations were also significantly associated with genotype in men and levels were approximately 10% higher in carriers homozygous for the rare alleles as compared to subjects homozygous for the common alleles (-482C>T, P=0.04; -455T>C, P=0.006). In addition, there was a strong interaction between both variants and cigarette smoking affecting fasting triglyceride levels in both men (interaction: -455T>C, P=0.02; -482C>T, P=0.008) and women (interaction: -455T>C, P=0.007; -482C>T, P=0.013). Taken together, the data shows that men who carry the rare alleles of the IRE variants have disturbed glucose homeostasis and an unfavourable lipid phenotype. The finding of an elevated 30-min NEFA may be an important mechanistic link between triglyceride-rich lipoprotein (TRL) metabolism and glucose homeostasis.     

长白山区柳兰的开发利用及园艺栽培技术

柳兰Chamaenerion angustifolium在长白山野生花卉中具有较高的观赏价值,通过引种及园艺栽培,探讨了繁育及园艺栽培技术,机械矮化用摘心法矮化效果和观赏效果突出。药用矮化选用B9矮化效果明显,花茎比例均衡。为其开发利用资源提供了科学依据。     

Cold stress causes rapid but differential changes in properties of plasma membrane H-ATPase of camelina and rapeseed

Camelina (Camelina sativa) and rapeseed (Brassica napus) are well-established oil-seed crops with great promise also for biofuels. Both are cold-tolerant, and camelina is regarded to be especially appropriate for production on marginal lands. We examined physiological and biochemical alterations in both species during cold stress treatment for 3 days and subsequent recovery at the temperature of 25 °C for 0, 0.25, 0.5, 1, 2, 6, and 24 h, with particular emphasis on the post-translational regulation of the plasma membrane (PM) H⁺-ATPase (EC3.6.3.14). The activity and translation of the PM H⁺-ATPase, as well as 14-3-3 proteins, increased after 3 days of cold stress in both species but recovery under normal conditions proceeded differently. The increase in H⁺-ATPase activity was the most dramatic in camelina roots after recovery for 2 h at 25 °C, followed by decay to background levels within 24 h. In rapeseed, the change in H⁺-ATPase activity during the recovery period was less pronounced. Furthermore, H⁺-pumping increased in both species after 15 min recovery, but to twice the level in camelina roots compared to rapeseed. Protein gel blot analysis with phospho-threonine anti-bodies showed that an increase in phosphorylation levels paralleled the increase in H⁺-transport rate. Thus our results suggest that cold stress and recovery in camelina and rapeseed are associated with PM H⁺-fluxes that may be regulated by specific translational and post-translational modifications.