Glutamate levels control HT22 murine hippocampal cell death by regulating biphasic patterns of Erk1/2 activation: role of metabolic glutamate receptor 5

Extracellular glutamate concentration is a critical determinant of neuronal cell fate. We recently demonstrated that HT22 murine hippocampal cell viability was reduced by exposure to high concentrations of glutamate, whereas low concentrations promoted cell survival. Extracellular signal-regulated kinase (Erk)1/2 activation by glutamate is important for both glutamate-induced cell death and survival. In this study, we investigated the role of glutamate-induced or hydrogen peroxide (H₂O₂)-induced Erk1/2 activation in HT22 cell fate determination. Glutamate and H₂O₂ treatment similarly induced early (<1 h) Erk1/2 phosphorylation regardless of concentration. On the other hand, persistent Erk1/2 phosphorylation (16–24 h) was observed only in the presence of excess glutamate. Only the latter contributed to glutamate-induced cell death, which involved metabolic glutamate receptor 5. Our findings suggest that glutamate concentration modulates two distinct phases of Erk1/2 activation, which can explain the glutamate concentration-dependent determination of HT22 cell fate.     

N-Alkylated arylsulfonamides of (aryloxy)ethyl piperidines: 5-HT7 receptor selectivity versus multireceptor profile

The N-alkylation of the sulfonamide moiety, in a group of arylsulfonamide derivatives of (aryloxy)ethyl piperidines, may be considered as a strategy for the design of selective 5-HT₇ receptor ligands or multifunctional agents to extend a polypharmacological approach to the treatment of complex diseases. The study allowed for the identification of 31 (1-methyl-N-{1-[2-(2-(t-butyl)phenoxy)ethyl]piperidin-4-yl}-N-cyclopropylmethyl-1H-pyrazole-4-sulfonamide), a potent and selective 5-HT₇ receptor antagonist and 33 (1-methyl-N-{1-[2-(biphenyl-2-yloxy)ethyl]piperidin-4-yl}-N-cyclopropylmethyl-1H-pyrazole-4-sulfonamide), as multimodal 5-HT/dopamine receptor ligand, as 5-HT_2A/5-HT₇/D₂ receptor antagonists. Both selected compounds were evaluated in vivo in a forced swim test (FST) in mice and in a novel object recognition (NOR) task in rats, demonstrating distinct antidepressant-like and pro-cognitive properties (MED = 1.25 mg/kg and 1 mg/kg, ip, respectively). These findings warrant further studies to explore the therapeutic potential of N-alkylated arylsulfonamides for the treatment of CNS disorders.     

Molecular-assisted alpha taxonomy of the genus Rhodymenia (Rhodymeniaceae,Rhodymeniales) from Australia reveals overlooked species diversity

A previously published DNA barcode survey of red macroalgae in Australia revealed significant cryptic and overlooked diversity for the genus Rhodymenia with recognition of R. novahollandica, R. prolificans, R. stenoglossa, R. wilsonis and an additional four uncharacterized genetic species groups. Since that study, increased sampling effort in Australia has warranted reassessment and reinvestigation of the number of genetic species groups attributed to Rhodymenia and their respective taxonomic affiliations. Using molecular-assisted alpha taxonomy employing the DNA barcode (COI-5P), the present study resolved 188 Australian specimens in 12 genetic species groups assignable to the genus Rhodymenia. Four of these groups were attributed to the previously recognized species (above), whereas some collections from Lord Howe Island were attributed to the New Zealand species R. novazelandica, expanding its biogeographic range. The following seven genetic groups were inconsistent with existing species of Rhodymenia and established as novel taxa: R. compressa sp. nov., R. contortuplicata sp. nov., R. gladiata sp. nov., R. insularis sp. nov., R. lociperonica sp. nov., R. norfolkensis sp. nov. and R. womersleyi sp. nov. Although morphological and biogeographic features were adequate for distinguishing some species of Rhodymenia from Australia, DNA sequencing in combination with morphology and biogeography provided the most reliable means of identification.     

Design,physico-chemical properties and biological evaluation of some new N-[(phenoxy)alkyl]- and N-{2-[2-(phenoxy)ethoxy]ethyl}aminoalkanols as anticonvulsant agents

A series of thirty N-(phenoxy)alkyl or N-{2-[2-(phenoxy)ethoxy]ethyl}aminoalkanols has been designed, synthesized and evaluated for anticonvulsant activity in MES, 6 Hz test, and pilocarpine-induced status epilepticus. Among the title compounds, the most promising seems R-(−)-2N-{2-[2-(2,6-dimethylphenoxy)ethoxy]ethyl}aminopropan-1-ol hydrochloride (22a) with proved absolute configuration with X-ray analysis and enantiomeric purity. The compound is effective in MES test with ED₅₀ = 12.92 mg/kg b.w. and its rotarod TD₅₀ = 33.26 mg/kg b.w. The activity dose is also effective in a neurogenic pain model—the formalin test. Within high throughput profile assay, among eighty one targets, the strongest affinity of the compound is observed towards σ receptors and 5-HT transporter and the compound does not bind to hERG. It also does not exhibit mutagenic properties in the Vibrio harveyi test. Moreover, murine liver microsomal assay and pharmacokinetics profile (mice, iv, p.o., ip) indicate that the liver is the primary site of biotransformation of the compound, suggesting that both 22a and its metabolite(s) are active, compensating probably low bioavailability of the parent molecule.     

5-氨基乙酰丙酸对苹果叶片耐弱光能力的影响

为了探讨5-氨基乙酰丙酸(ALA)对苹果耐弱光性的影响,以‘润太2号’和‘郑优3号’两个品种苹果为材料,设置露天对照(CK)、轻度遮荫(LS)和重度遮荫(SS)3种光照条件,通过根际浇灌法研究了10mg·L~(-1) ALA处理对弱光条件下苹果叶片活性氧代谢与叶绿素荧光特性的影响。结果显示:(1)与CK相比,弱光胁迫显著降低了两品种苹果叶片的超氧化物歧化酶(SOD)与过氧化物酶(POD)的活性,增大了超氧阴离子(O_2~(-·))产生速率以及过氧化氢(H2O2)和丙二醛(MDA)含量,且‘郑优3号’的活性氧产生速率及MDA含量在弱光下的升高幅度更大;ALA处理显著提高了弱光胁迫下两品种的保护酶活性,降低了活性氧产生速率和MDA含量,并以耐弱光性较差的‘郑优3号’的变化更显著。(2)在弱光胁迫下,苹果叶片的叶绿素含量和叶绿素b/a升高,而ALA处理使二者进一步显著升高。(3)弱光胁迫下,苹果叶片的叶绿素荧光参数V_J、M_o、DI_o/RC显著升高,而ψ_o、ψE_o、ψR_o、PI_(ABS)、PI_(CS)和PI_(total)显著降低;ALA处理抑制了叶绿素荧光参数在弱光胁迫下的变化,甚至使其达到优于对照的水平。研究表明,弱光条件下苹果的抗氧化能力较差,受到明显的氧化伤害,且‘郑优3号’的耐弱光能力比‘润太2号’差;ALA处理提高了苹果在弱光下的抗氧化能力,降低了弱光对苹果叶片的氧化伤害,同时还提高了弱光条件下苹果叶片捕捉、传递和转化光能的效率,改善了光合电子传递情况,增大了苹果叶片在弱光胁迫下的光能利用效率,改善了光合性能;根灌ALA可以明显提高苹果的耐弱光性。     

蝉虫草样品的分级萃取与化学成分分析

利用索氏萃取技术,依次采用石油醚、乙酸乙酯、丙酮、无水乙醇和甲醇等5种溶剂对蝉虫草纯粉进行分级萃取,运用傅里叶变换红外光谱分析法和气相色谱-质谱联用技术对5级萃取物进行分析鉴定。傅里叶变换红外光谱分析显示萃取物中含有与烯烃类、羧酸类、酯类、醇类和酮类等化合物相关的C-H、C=O、C-O和C=C等官能团。气相色谱-质谱联用技术共鉴定出有机小分子化合物34种,以酯类和脂肪酸类为主,多为碳链长度为15-20的长链脂肪酸及对应的酯,其中十八碳不饱和脂肪酸相对含量高达28.95%;分别存在于两种或以上萃取物中的有机化合物共有11种;仅存于石油醚萃取物中的化合物6种,乙酸乙酯萃取物中3种,丙酮萃取物中2种,无水乙醇萃取物中6种,甲醇萃取物中6种。在一定极性范围内,利用溶剂的极性梯度变化,可实现蝉虫草中活性物质的按极性梯度分离;采用分级萃取技术可有效分离蝉虫草中部分化学成分。鉴定结果充实了蝉虫草中化合物的种类资源,为蝉虫草中活性物质谱图库的完善、构效关系的建立及蝉虫草产品的利用开发提供支撑。     

IARS2在胃癌预后中的临床应用

为检测IARS2和MYO5B在胃癌组织中的表达并探讨IARS2表达与胃癌患者临床病理特征及预后的关系,本研究使用荧光定量PCR (quantitative polymerase chain reaction, qRT-PCR)及Western blotting检测30例胃癌组织和癌旁组织中IARS2和MYO5B的表达,使用线性回归分析两者m RNA表达相关性。使用免疫组化方法检测86对胃癌组织及癌旁组织中IARS2蛋白的表达情况,根据免疫组化IARS2表达情况将胃癌患者分为IARS2阳性组和阴性组,比较两组患者临床病理特征及预后情况。结果发现,较之癌旁组织,IASR2在胃癌组织中显著高表达(p<0.05),而MYO5B在胃癌组织中显著低表达(p<0.05),且两者表达负相关(r=0.5768, p=0.0008)。免疫组化显示IASR2阳性细胞在胃癌组织中的阳性率为70.9%。IASR2高表达提示更高的胃癌淋巴结转移(p=0.041)和TNM分期(p=0.004)及更低的患者术后5年总生存率(p=0.000 6)。研究提示IARS2在胃癌组织中高表达,可作为评估胃癌预后的标志物。     

miR‐20a‐5p regulates pulmonary surfactant gene expression in alveolar type II cells

MicroRNA (miRNA) critically controls gene expression in many biological processes, including lung growth and pulmonary surfactant biosynthesis. The present study was conducted to investigate whether miR‐20a‐5p had such regulatory functions on alveolar type II (AT‐II) cells. To accomplish this, miR‐20a‐5p–overexpressed and miR‐20a‐5p–inhibited adenoviral vectors were constructed and transfected into cultured AT‐II cells that were isolated from rat foetal lungs of 19 days' gestation. Transfection efficiency was confirmed by observing the fluorescence of green fluorescent protein (GFP) carried by the viral vector, whereas miR‐20a‐5p levels were verified by real‐time PCR. The CCK‐8 assay was used to compare the proliferation ability of AT‐II cells that had over‐ or underexpressed miR‐20a‐5p. The expression of surfactant‐associated proteins (SPs) and phosphatase and tensin homolog (PTEN) was measured by real‐time PCR and Western blotting. In AT‐II cells, transfection resulted in over‐ or under‐regulation of miR‐20a‐5p. While overexpression of miR‐20a‐5p promoted pulmonary surfactant gene expression, its underexpression inhibited it. Consistent with its role in negatively regulating the pulmonary surfactant gene, an opposite pattern was observed for miR‐20a‐5p regulation of PTEN. As a result, when miR‐20a‐5p was rendered overexpressed, PTEN was down‐regulated. By contrast, when miR‐20a‐5p was underexpressed, PTEN was up‐regulated. Neither overexpression nor underexpression of miR‐20a‐5p altered the cell proliferation. miR‐20a‐5p plays no role in proliferation of foetal AT‐II cells but is a critical regulator of surfactant gene expression. The latter appears to be achieved through a regulatory process that implicates expression of PTEN.     

5,2′‐dibromo‐2,4′,5′‐trihydroxydiphenylmethanone attenuates LPS‐induced inflammation and ROS production in EA.hy926 cells via HMBOX1 induction

Inflammation and reactive oxygen species (ROS) are important factors in the pathogenesis of atherosclerosis (AS). 5,2′‐dibromo‐2,4′,5′‐trihydroxydiphenylmethanone (TDD), possess anti‐atherogenic properties; however, its underlying mechanism of action remains unclear. Therefore, we sought to understand the therapeutic molecular mechanism of TDD in inflammatory response and oxidative stress in EA.hy926 cells. Microarray analysis revealed that the expression of homeobox containing 1 (HMBOX1) was dramatically upregulated in TDD‐treated EA.hy926 cells. According to the gene ontology (GO) analysis of microarray data, TDD significantly influenced the response to lipopolysaccharide (LPS); it suppressed the LPS‐induced adhesion of monocytes to EA.hy926 cells. Simultaneously, TDD dose‐dependently inhibited the production or expression of IL‐6, IL‐1β, MCP‐1, TNF‐α, VCAM‐1, ICAM‐1 and E‐selectin as well as ROS in LPS‐stimulated EA.hy926 cells. HMBOX1 knockdown using RNA interference attenuated the anti‐inflammatory and anti‐oxidative effects of TDD. Furthermore, TDD inhibited LPS‐induced NF‐κB and MAPK activation in EA.hy926 cells, but this effect was abolished by HMBOX1 knockdown. Overall, these results demonstrate that TDD activates HMBOX1, which is an inducible protective mechanism that inhibits LPS‐induced inflammation and ROS production in EA.hy926 cells by the subsequent inhibition of redox‐sensitive NF‐κB and MAPK activation. Our study suggested that TDD may be a potential novel agent for treating endothelial cells dysfunction in AS.