GluN2B-NMDA receptors in Alzheimer's disease:beyond synapse loss and cell death

Alzheimer＇s disease （AD） is one of the most devastating dis- eases affecting the life and health of aging population. Two hallmarks of AD are senile plaques and neurofibrillary tan- gles, and AD is well known for the massive loss of neurons and impaired cognitive functions especially memory loss. Despite extensive search for effective treatment, available drugs have limited efficacy without affecting the course of AD. Significant efforts have been devoted to curb the pro- duction of amyloid [3 （A[3; the major component of plaques） or enhance the clearance of it, with the aim to reduce the accumulation of plaque in the brain. Antibodies that can bind A[3 to increase their removal have received a lot of at- tention although recent clinical trial results have been largely negative and disappointing （Panza et al., 2014）. Targets that are not directly related to A[3 have also been pursued. One such target is N-methyl-D-aspartate （NMDA） receptors （NMDARs）, a subclass of glutamate receptors. The antago- nist of NMDAR memantine has been approved for treating moderate to severe AD, although the exact mechanism un- derlying its action is still in debate （Kotermanski and John- son, 2009）.

Influences of NR2B-containing NMDA Receptors Knockdown on Neural Activity in Hippocampal Newborn Neurons

Summary： Adult-bom neurons undergo a transient period of plasticity during their integration into the neural circuit. This transient plasticity may involve NMDA receptors containing NR2B, the major sub unit expressed at early developmental stages. The main objective of the present study was to investigate the effects of NR2B gene knockdown on the functional integration of the adult-born granule cells gen- erated from the subgranule zone （SGZ） in the hippocampus. The small interfering RNA （siRNA） was used to knock down the NR2B gene in the adult-born hippocampal neurons. In the functional integration test, the mice were exposed to a novel environment （open field arena）, and the expression of c-fos was immunohistochemically detected in the hippocampus. After exposure to the novel environment, siRNA-NR2B mice were significantly different from control mice in either the number of squares or the number of rears they crossed, showing decreased horizontal and vertical activity （P〈0.05）. Moreover, the c-fos expression was increased in both control and siRNA-NR2B mice after open field test. But, it was significantly lower in siRNA-NR2B neurons than in control neurons. It was concluded that the neu- ral activity of newborn neurons is regulated by their own NR2B-containing NMDA glutamate receptors during a short, critical period after neuronal birth.

人参皂甙-Rd对SNI大鼠痛觉异常及脊髓背角内谷氨酸和NR2A/B表达的影响

目的:探讨人参皂甙-Rd(G-Rd)对大鼠神经病理性痛的镇痛效果及其机制。方法:成年雄性SD大鼠(30只)随机分成五组:空白对照组(blank control)、坐骨神经分支选择损伤组(spared nerve injury,SNI)、假手术组(sham operation)、SNI+saline(腹腔注射,i.p.)组、SNI+G-Rd(i.p.)组。行为学用von Frey法测定上述各组手术侧后肢机械缩足反射阈值(PWMT),以评定大鼠SNI术后痛敏变化以及人参皂甙-Rd的镇痛效果;用免疫荧光法检测对比上述各组大鼠脊髓L4-6节段背角内谷氨酸样和N-甲基-D-天冬氨酸受体2A/B亚单位(NR2A/B)样免疫阳性物的平均荧光强度(MFI)。结果:SNI术后10 d,手术侧PWMT值明显低于空白对照组和假手术组,术后20 d达到最低值,SNI+G-Rd组PWMT值明显高于SNI+Saline组(P<0.05)。免疫荧光染色显示SNI术后20 d,脊髓L4-6节段手术侧背角内谷氨酸样和NR2A/B样免疫阳性产物的MFI明显高于空白对照组和假手术组(P<0.05);SNI+G-Rd组脊髓L4-6节段手术侧背角内的谷氨酸样免疫阳性产物的MFI明显低于SNI和SNI+S组(P<0.05),而NR2A/B的MFI未见显著变化(P>0.05)。结论:人参皂甙-Rd可显著改善SNI引起的大鼠痛过敏行为,其可能的脊髓机制之一是与其有效地减少相应脊髓节段背角内谷氨酸的含量有关。

急性脑缺血再灌注大鼠NMDA受体NR2A/B表达的变化及其作用机制分析

目的探讨急性脑缺血再灌注大鼠NMDA受体NR2A/B表达的变化及其作用机制分析。方法 2016年8月—2017年9月选取60只雄性Wistar大鼠随机分为对照组、假手术组、脑缺血再灌注组,每组20只。采用动脉引流法进行7 min全脑缺血,再灌注造模,术后在不同时间段对大鼠进行取脑,对脑组织进行切片,放于恒冷箱中保存,进行免疫细胞化学ABC反应与利用图像分析系统进行免疫阳性监测。结果对照组大鼠的NR2A阳细胞数、平均灰度、平均光密度优于假手术组、脑出血再灌注组(P<0.05)。脑出血再灌注组大鼠阳细胞数、平均灰度、平均光密分别为(74.3±12.4)、(134.4±6.8)、(0.28±0.02),脑出血再灌注组大鼠NR2A、NR2B免疫阳性面积6 h后高于对照组,假手术组6 h后免疫阳性面积高于对照组(P<0.05),72 h 3组大鼠免疫阳性面积差异无统计学意义(P>0.05)。结论脑缺血再灌注可以导致NR2B、NR2A蛋白表达产生变化,调节NMDA受体的整体功能活性,减轻脑缺血再灌注引起的局灶性脑损伤,对脑神经起到保护作用。

Influences of Microwave on the Cognitive Function of Chickling and the Gene Expression of NMDA Receptor Subunit

[Objective] The research aimed to study the effects of microwave on the chick embryo development and the cognitive function of chickling. [Method] The microwave which was transmitted by the permatron and was 2 450 MHz was used to simulate the microwave radiation source to radiate the hatching eggs until the chickling was hatched out. The disposable passive avoidance learning and RT-PCR were respectively used to detect the influences of microwave on the cognitive function of chickling and the expression amounts of NMDA receptor NR1 and NR2 subunits. [Result] After the microwave radiation,the avoidance rate of exposed group was significantly lower than that in the control group. Especially the avoidance rate of highest radiation intensity group was extremely significantly lower than that in the control group. Meanwhile,the body weights of two groups of chickling in the exposed group increased,and the hatching time in one group increased. Via RT-PCR analysis,the expression amount of NR2 subunit increased on the 10th day and the 15th day. The expression amount of NR1 subunit only decreased on the 15th day. [Conclusion] The microwave had the certain influence on the individual development. By changing the structure composition and function of NMDA receptor in the endbrain,the microwave made the self-regulation ability of chickling decline,which had the certain damage on the cognitive function.

Bioinformatic analysis of human nuclear receptor nr5a2(hb1f) genomic sequence

We have cloned the cDNA of human nuclear receptor nr5a2(hb1f) gene and obtained its whole genomic sequence previously. In this work we carried out in-depth bioinformatic analysis on the genomic sequence of nr5a2(hb1f) gene. Sequence comparison and prediction algorithms implicated that there might be additional coding regions in the 210 kb genomic sequence besides known exons, especially in the two largest introns. Comparison of the structures of nr5a loci in different species revealed distinguishable conservation and apparent gene duplication during evolution. The remarkable conservation among promoters of zebrafish, mouse and human nr5a2 genes suggested that they would be regulated by the same transcription factors.

电针对吗啡戒断大鼠杏仁核内N-甲基-D-天门冬氨酸受体亚单位NR2B蛋白及基因表达的影响

目的:观察电针对吗啡戒断大鼠空间学习记忆的影响,通过对杏仁核脑区N-甲基-D-天门冬氨酸受体亚单位NR 2B表达的检测,探讨电针改善大鼠吗啡戒断后学习记忆能力的分子生物学机制。方法:雄性SD大鼠,随机分为空白组、模型组、针刺组以及电针组,每组10只。以每日20,30,40,50,50mg/kg剂量,连续5d背部皮下注射盐酸吗啡,建立吗啡依赖大鼠模型,末次注射后3h给予纳洛酮快速戒断。两个治疗组选取"足三里""肾俞"穴分别施以手针和电针,每次15min,每日1次,连续治疗6d。应用Morris水迷宫测试戒断大鼠空间学习能力,应用蛋白印记(Western blot)及实时荧光定量聚合酶链反应(RT-PCR)技术检测戒断大鼠杏仁核NR 2B蛋白与基因的表达水平。结果:模型组大鼠的逃避潜伏期较空白组明显延长(P<0.01),针刺及电针组则较模型组显著缩短(P<0.01),电针组较针刺组缩短更明显(P<0.05);模型组大鼠的杏仁核NR 2B蛋白表达较空白组显著降低(P<0.01),针刺组、电针组则较模型组表达升高(P<0.01),电针组高于针刺组(P<0.01);模型组NR 2BmRNA表达较空白组显著降低(P<0.01),电针组较模型组表达升高(P<0.05)。结论:吗啡戒断后大鼠空间学习能力受损,针刺及电针可以恢复大鼠学习能力且电针组疗效优于针刺组,推测可能与其对杏仁核NR 2B表达的调节有关。

Effect of electroacupuncture on expression of NR2B in prefrontal cortex in morphine-withdrawal rats

Objective To observe the effect of electroacupuncture （EA） on learning and memory abilities and expression of N-methyI-D-aspartate receptor subunit （NR2B） in prefrontal cortex in morphine-withdrawal rats and to investigate the molecular biological mechanisms. Methods Thirty-six male SD rats were randomly divided into four groups, namely control group （group A）, model group （group B）, model with acupuncture group （group C） and model with electroacupunture group （group D）, with 9 in each group. All rats except those in group A were subcutaneously injected with morphine hydrochloride injectio on the back with daily dosage increased day by day. Naloxone was given 3 h after the last injection to establish the models of morphinewithdrawal rats. After the models were established, the rats were treated with acupuncture and electroacupuncture respectively at bilateral ＂Shenshu＂ （肾俞 BL 23） and ＂Zusanli＂ （足三里 ST 36） for 15 min per time, once daily for 6 days. Space learning and memory abilities of the rats were measured by Morris water maze, and protein and gene expression levels of NR2B in prefrontal cortex were measured by Western Blot and RT-PCR. Results In place navigation test, the escape latency in group B, group C and group D was significantly prolonged compared with that of group A （P〈0.01）, the escape latency in group C and group D was significantly shortened compared with that of group B （P〈0.01） and the escape latency in group D was significantly shortened compared with that of group C （P〈0.05）; during spatial probe test, the number of times crossing the platform of group B, group C and group D decreased compared with that of group A （P〈0.01）, and compared with group B, the number of times crossing the platform of group C increased and the number of group D significantly increased （P〈0.01）. Decreased protein expression level of NR2B was found in group B when compared with that of group A （P〈0.01）, increased protein expression levels of NR2B were found in group C and group D when compared with that of group B （P〈0.01）, however, the expression level in group D was higher than that in group C （P〈0.01）. mRNA expression level of NR2B in prefrontal cortex in morphine-withdrawal rats decreased （P〈0.05）, however, compared with that of group B, the expression level increased in group D （P〈0.05）, and there was no statistical significance in increased expression level in group C （P〉0.05）. Conclusion Acupuncture and eletroacupunture can improve space learning and memory abilities of merphine-withdrawal rats, with better efficacy of eletroacupuncture than that of acupuncture, the mechanisms of which may be associated with the regulation of NR2B expression in prefrontal cortex.

Metabolic and Endocrine Responses of Desert-Adapted Mice Reproductive System to Increased Salinity

From an evolutionary point of view, reproduction timing is an important adaptation which enables the transfer of genetic properties, thus enabling species continuation. Rodents inhabiting arid environments need reliable cues for triggering their reproduction. Results of previous studies showed that increased dietary salinity plays an important role as an ultimate regulator for desert adapted rodents＇ reproductive system. The authors aimed discovering pathways by which high salinity can affect the reproductive system and metabolic status of desert adapted common spiny mice, Acomys cahirinus. Mice were challenged with osmotic stress, water source salinity increased gradually from 0.9% - 5% NaCI under short days （SD） and long days （LD）. The authors assessed leptin and free fatty acid （FFA） levels using ELISA while, SYBR green technology was used for relative receptor expression （RQ） of target genes. Results revealed that serum levels of the hormone leptin were significantly （P 〈 0.05） reduced in salinity treated （ST） mice. Levels of FFA were significantly （P 〈 0.05） increased in LD- and SD-ST-males. In ST-SD females a significant increase （P 〈 0.05） in expression levels of leptin （Ob-Rt） mRNA receptor gene, in ovaries was noted. Aldosteron （Nr3c2） and vasopressin （AVP） mRNA receptor expression genes levels were significantly （P 〈 0.05） increased in both LD- and SD- ST- males.

Design,Synthesis and Biological Evaluation of Pyrrolo[2,1-c][1,4]benzodiazepine-3,11-dione Derivatives as Novel Neuroprotective Agents

A series of pyrrolo[2,1-c][1,4]benzodiazepine-3,11-dione derivatives was designed and synthesized,and their neuroprotective activity against SH-SY5Y cell injury induced by N-methyl-D-aspartic acid(NMDA)was evaluated.All the compounds showed significant neuroprotective effects,especially B16,which showed excellent performance and better activity than the positive control ifenprodil(B16:56.2%±0.6%;ifenprodil:41.0%±2.7%).Further investigation indicated that B16 could attenuate the Ca^(2+)influx induced by NMDA in SH-SY5Y cells and Western blotting also showed that B16 could attenuate the NR2B upregulation in SH-SY5Y cells induced by NMDA.The molecular docking results showed that compound B16 fitted in the binding pocket of NR2B-NMDAR well and could interact with binding sites of compounds 1 and 2 simultaneously.The ADME/Tox prediction results suggested that compound B16 had good blood-brain barrier(BBB)permeability and the zero alert of Pan Assay Interference Structures(PAINS)indicated that B16 could not elicit false-positive activities.These results strongly suggest that B16 is a promising and effective candidate neuroprotective compound,and that NR2B-NMDAR is a potential target of B16.

PXR:a center of transcriptional regulation in cancer

Pregnane X receptor(PXR,NR 112)is a prototypical member of the nuclear receptor superfamily.PXR can be activated by both endobiotics and xenobiotics.As a key xenobiotic receptor,the cellular function of PXR is mostly exerted by its binding to the regulatory gene sequences in a liganddependent manner.Classical downstream target genes of PXR participate in xenobiotic responses,such as detoxification,metabolism and inflammation.Emerging evidence also implicates PXR signaling in the processes of apoptosis,cell cycle arrest,proliferation,angiogenesis and oxidative stress,which are closely related to cancer.Here,we discussed,in addition to the characterization of PXR per se,the biological function and regulatory mechanism of PXR signaling in cancer,and its potential for the targeted prevention and therapeutics.