MicroRNA-322 Cluster Promotes Tau Phosphorylation via Targeting Brain-Derived Neurotrophic Factor

Brain-derived neurotrophic factor (BDNF) is a crucial regulator to support synaptic plasticity and neuronal survival, its significant decrease is a pathophysiological hallmark in Alzheimer’s disease (AD) brains and accounts for poor prognosis. MicroRNAs (miRNAs) interfere with the translation of target mRNAs and control a variety of physiological and pathological processes. MiR-322 is the rodent homologue of human miR-424, it is involved in the modulation of cell differentiation, proliferation, apoptosis and metabolic activities in diverse tissues and organs. However, the roles and potential mechanisms of miR-322 remain elusive in AD pathogenesis. Here we observed miR-322 is significantly increased along with BDNF decrease in AD mouse brain. Bioinformatics prediction implicated that BDNF 3′-untranslated region (3′-UTR) possesses the putative target sequence of miR-322. Luciferase reporter assay identified that miR-322 can directly conjugate to BDNF 3′-UTR. The functional research showed that MiR-322 input deregulates BDNF expression at either mRNA or protein levels, whereas miR-322 silence restores BDNF expression in vitro. Furthermore, we found miR-322 promotes Tau phosphorylation via negatively controlling BDNF–TrkB receptor activation, otherwise MiR-322 silence restores TrkB activation and attenuates tau phosphorylation. Collectively, this study demonstrated a novel miRNA-dependent manner of BDNF degradation in AD pathogenesis, it may drive a miRNAs- or BDNF based therapeutic strategies against Alzheimer’s disease.     

hTRT反义基因转染对人结肠癌细胞生长的抑制作用

利用基因重组技术,hTRT基因反向插入真核表达载体pcDNA3．0,获得重组体pcDRTRT,通过脂质体法导入人结肠癌细胞株SW-111C,获得稳定转染细胞系,即反义细胞,该细胞易脱落,出现明显生长抑制现象;失去叠落生长能力;流式细胞仪(FCM)证实导入反义hTRT后,G0/1期细胞增加,G2M和S期细胞减少,增殖指数(PI)降低;且不能在软琼脂中形成集落;并发现反义细胞中hTRT表达水平明显下降。说明反义hTRT基因体外导入结肠在细胞株SW-111C可以明显降低端粒酶活性,抑制结肠癌细胞的生长、增殖且能使其恶性表型发生逆转。     

Combining evolutionary and structural information for local protein structure prediction

We study the effects of various factors in representing and combining evolutionary and structural information for local protein structural prediction based on fragment selection. We prepare databases of fragments from a set of non-redundant protein domains. For each fragment, evolutionary information is derived from homologous sequences and represented as estimated effective counts and frequencies of amino acids (evolutionary frequencies) at each position. Position-specific amino acid preferences called structural frequencies are derived from statistical analysis of discrete local structural environments in database structures. Our method for local structure prediction is based on ranking and selecting database fragments that are most similar to a target fragment. Using secondary structure type as a local structural property, we test our method in a number of settings. The major findings are: (1) the COMPASS-type scoring function for fragment similarity comparison gives better prediction accuracy than three other tested scoring functions for profile-profile comparison. We show that the COMPASS-type scoring function can be derived both in the probabilistic framework and in the framework of statistical potentials. (2) Using the evolutionary frequencies of database fragments gives better prediction accuracy than using structural frequencies. (3) Finer definition of local environments, such as including more side-chain solvent accessibility classes and considering the backbone conformations of neighboring residues, gives increasingly better prediction accuracy using structural frequencies. (4) Combining evolutionary and structural frequencies of database fragments, either in a linear fashion or using a pseudocount mixture formula, results in improvement of prediction accuracy. Combination at the log-odds score level is not as effective as combination at the frequency level. This suggests that there might be better ways of combining sequence and structural information than the commonly used linear combination of log-odds scores. Our method of fragment selection and frequency combination gives reasonable results of secondary structure prediction tested on 56 CASP5 targets (average SOV score 0.77), suggesting that it is a valid method for local protein structure prediction. Mixture of predicted structural frequencies and evolutionary frequencies improve the quality of local profile-to-profile alignment by COMPASS.     

<Emphasis Type="Italic">Nibribacter flagellatus</Emphasis> sp. nov., isolated from rhizosphere of <Emphasis Type="Italic">Hibiscus syriacus</Emphasis> and emended description of the genus <Emphasis Type="Italic">Nibribacter</Emphasis>

A Gram-stain negative, aerobic, motile by flagella, rod-shaped strain (THG-T16^T) was isolated from rhizosphere of Hibiscus syriacus. Growth occurred at 10–40 °C (optimum 28–30 °C), at pH 6.0–8.0 (optimum 7.0) and at 0–1.0% NaCl (optimum 0%). Based on 16S rRNA gene sequence analysis, the near phylogenetic neighbours of strain THG-T16^T were identified as Nibribacter koreensis KACC 16450^T (98.6%), Rufibacter roseus KCTC 42217^T (94.7%), Rufibacter immobilis CCTCC AB 2013351^T (94.5%) and Rufibacter tibetensis CCTCC AB 208084^T (94.4%). The DNA G+C content of strain THG-T16^T was determined to be 46.7 mol%. DNA–DNA hybridization values between strain THG-T16^T and N. koreensis KACC 16450^T, R. roseus KCTC 42217^T, R. immobilis CCTCC AB 2013351^T, R.tibetensis CCTCC AB 208084^T were 33.5?±?0.5% (31.7?±?0.7% reciprocal analysis), 28.1?±?0.2% (25.2?±?0.2%), 17.1?±?0.9% (10.2?±?0.6%) and 8.1?±?0.3% (5.2?±?0.1%). The polar lipids were identified as phosphatidylethanolamine, two unidentified aminophospholipids, an unidentified aminolipid and three unidentified lipids. The quinone was identified as MK-7 and the polyamine as sym-homospermidine. The major fatty acids were identified as C_16:1 ω5c, C_17:1 ω6c, iso-C_15:0, summed feature 3 (C_16:1 ω7c and/or C_16:1 ω6c) and summed feature 4 (iso-C_17:1 I and/or anteiso-C_17:1 B). On the basis of the phylogenetic analysis, chemotaxonomic data, physiological characteristics, and DNA–DNA hybridization data, strain THG-T16^T represents a novel species of the genus Nibribacter, for which the name Nibribacter flagellatus sp. nov. is proposed. The type strain is THG-T16^T(=?KACC 19188^T?=?CCTCC AB 2016246^T).     

丙戊酸钠对LPS诱导的急性呼吸窘迫综合征小鼠的治疗作用

为了探讨丙戊酸钠(valproic acid,VPA)对急性呼吸窘迫综合征(acute respiratory distress syndrome,ARDS)小鼠治疗作用及分子机制,本研究将30只雌性C57BL/6小鼠分为空白组、LPS组、LPS+VPA组,LPS+VPA组小鼠造模前腹腔预注射VPA,以LPS气管内注射诱导ARDS小鼠模型,6 h后检测各组小鼠肺水肿(湿重/干重),检测各组小鼠血液SOD和MDA水平;通过ELISA检测各组小鼠肺泡灌洗液中TNFα和IL-1β水平,Western blotting检测各组小鼠NF-κB p65和p-H2A.X蛋白表达水平。研究结果表明:与空白组相比,LPS组小鼠肺水肿显著升高,与LPS组比较,LPS+VPA组和阳性组小鼠肺水肿显著降低,差异具有统计学意义(p<0.01)。ELISA结果显示,与空白组比较,LPS组小鼠肺组织TNFα和IL-1β含量显著升高,与LPS组比较,LPS+VPA组小鼠肺组织TNFα和IL-1β含量显著降低,差异具有统计学意义(p<0.01)。与空白组比较,LPS组小鼠血液SOD活性显著降低,MDA含量显著升高,与LPS组比较,LPS+VPA组和阳性组小鼠血液SOD活性显著升高,MDA含量显著降低。Western blotting结果显示,与空白组比较,LPS组小鼠肺NF-κB p65和p-H2A.X蛋白表达显著升高,与LPS组比较,LPS+VPA组和阳性组小鼠肺NF-κB p65和p-H2A.X蛋白表达显著降低,差异具有统计学意义(p<0.01)。本研究初步表明:VPA能够抑制NF-κB通路,抑制小鼠氧化应激和炎症反应,保护ARDS小鼠肺组织。     

不同管理模式对茶树碳氮磷含量及其生态化学计量比的影响

植物不同器官的碳(C)、氮(N)、磷(P)含量及其生态化学计量特征能够反映植物内部的养分分配与平衡关系。该研究以福建安溪3种不同管理模式的铁观音茶园为研究对象, 设置了常规管理模式下的茶园(M1)、间作套种模式下的茶园(M2)和现代技术管理模式下的茶园(M3) 3种样地, 分析茶树根、茎、叶器官的C、N、P含量及其化学计量学特征, 养分的变异特征与异速生长关系。结果表明: M2和M3管理模式下茶树根、茎、叶N、P含量均显著高于M1管理模式, C含量差异不明显; 茶树根、茎、叶C:N、C:P、N:P均表现为M1 > M2 > M3。茶树不同器官C、N、P含量差异较大, 根据变异来源分析, 管理模式因素对C、N、P含量变异的影响均达到显著水平。根茎叶N-P的异速生长关系表明茶树不同器官的养分需求存在相似性; 土壤pH和容重是影响C:N、C:P、N:P的重要因素, 而土壤含水量和盐度对茶树根和叶C含量的影响较大。总体来讲, 间作套种以及现代化滴灌、水肥等管理模式可以改善茶树对养分的吸收效率, 对解决土壤养分不均衡问题具有正面效应。     

Quantitative evaluation of siRNA delivery in vivo

Effective small interfering RNA (siRNA)-mediated therapeutics require the siRNA to be delivered into the cellular RNA-induced silencing complex (RISC). Quantitative information of this essential delivery step is currently inferred from the efficacy of gene silencing and siRNA uptake in the tissue. Here we report an approach to directly quantify siRNA in the RISC in rodents and monkey. This is achieved by specific immunoprecipitation of the RISC from tissue lysates and quantification of small RNAs in the immunoprecipitates by stem-loop PCR. The method, expected to be independent of delivery vehicle and target, is label-free, and the throughput is acceptable for preclinical animal studies. We characterized a lipid-formulated siRNA by integrating these approaches and obtained a quantitative perspective on siRNA tissue accumulation, RISC loading, and gene silencing. The described methodologies have utility for the study of silencing mechanism, the development of siRNA therapeutics, and clinical trial design.     

Comparison between GdDTPA and two gadolinium polyoxometalates as potential MRI contrast agents

Two gadolinium polyoxometalates, Gd(2)P(2)W(18)O(62) and K(15)[(GdO)(3)(PW(9)O(34))(2)], have been evaluated by in vivo as well as in vitro experiments as the candidates of tissue-specific magnetic resonance imaging (MRI) contrast agents. T(1)-relaxivities of 28.4 mM(-1).s(-1) for Gd(2)P(2)W(18)O(62) and 11.2 mM(-1).s(-1) for K(15)[(GdO)(3)(PW(9)O(34))(2)] (400 MHz, 25 degrees C) were higher than that of the commercial MRI contrast agent (GdDTPA). Their relaxivities in bovine serum albumin and human serum transferrin were also reported. The favorable liver-specific contrast enhancement and renal excretion capability in in vivo MRI with Sprague-Dawley rats after i.v. administration of K(15)[(GdO)(3)(PW(9)O(34))(2)] was demonstrated. In vivo and in vitro assay showed that K(15)[(GdO)(3)(PW(9)O(34))(2)] is a promising liver-specific MRI contrast agent. However, Gd(2)P(2)W(18)O(62) did not show the favorable quality in vivo as expected from its high relaxivity in vitro, which was attributed to low bioavailability, indicating that it is of limited value as tissue-specific MRI contrast agent.     

A Double‐Edged Sword: Complement Component 3 in Toxoplasma gondii Infection

Sprague Dawley rats and Kunming (KM) mice are artificially infected with type II Toxoplasma gondii strain Prugniaud (Pru) to generate toxoplasmosis, which is a fatal disease mediated by T. gondii invasion of the central nervous system (CNS) by unknown mechanisms. The aim is to explore the mechanism of differential susceptibility of mice and rats to T. gondii infection. Therefore, a strategy of isobaric tags for relative and absolute quantitation (iTRAQ) is established to identify differentially expressed proteins (DEPs) in the rats’ and the mice's brains compared to the healthy groups. In KM mice, which is susceptible to T. gondii infection, complement component 3 (C3) is upregulated and the tight junction (TJ) pathway shows a disorder. It is presumed that T. gondii‐stimulated C3 disrupts the TJ of the blood–brain barrier in the CNS. This effect allows more T. gondii passing to the brain through the intercellular space.