树鼩在神经系统疾病中的应用研究进展

近年来研究表明,树鼩的生理、生化和解剖学等许多生物学特性比啮齿类更接近于人类。因此,关于树鼩的研究越来越广泛,涉及病毒、内分泌和肿瘤等方面。此外,树鼩是神经系统高度发达的动物,与啮齿类相比存在其特有的优势。概述了国内、外树鼩在脑血管病、抑郁症和阿尔兹海默病中的研究现状,以及CRISPR/Cas系统在树鼩中的运用前景,期望可以对今后的基础研究和临床研究提供导向作用。     

非人灵长类局部脑缺血动物模型研究现状

非人灵长类动物在种系发生上较啮齿类更接近于人类,用来制备局部脑缺血模型可以更好的拟合临床症状和机理。通过对国内外非人灵长类动物局部脑缺血模型的制备方法和应用现状进行收集、分类和述评,展望非人灵长类动物模型的应用前景,尤其是利用低等灵长类动物树鼩研究缺血性中风的优势。     

树鼩CD4全长编码序列的克隆及分子特征分析

树鼩作为多种人类疾病研究模型的可能性已受到广泛关注,但尚缺乏研究其免疫功能的基本标志以及单克隆抗体。该实验首先以树鼩外周血总RNA为材料,通过RT-PCR扩增得到长度为1365bp的树鼩CD4全长编码序列,并确定了数据库中缺失的两个片段,进而通过ClustalW等软件对其序列和分子特征进行分析,发现树鼩CD4氨基酸序列胞外和胞内域保守性较好,且与人类和猴的亲缘关系较近。虽然树鼩和人CD4分子表面大部分区域均带正电荷,但与人CD4胞外域D1相比,树鼩CD4D1结构区域表面带负电荷较多,且多出两个N-糖基化位点。这些差异对抗体的结合可能存在影响。该研究为今后树鼩CD4单克隆抗体制备及功能研究奠定了基础。     

抗炎性细胞因子与抑郁症

细胞因子假说是关于抑郁症发病机理的重要假说,为探讨抑郁症的发病机理和临床治疗方法提供了新方向.细胞因子分为前炎性细胞因子和抗炎性细胞因子.前炎性细胞因子与抑郁症的发病密切相关,而抗炎性细胞因子可能具有抗抑郁的作用.本文着重综述抗炎性细胞因子与抑郁症的关系.抗炎性细胞因子如白介素10、白介素1受体拮抗剂、白介素4、白介素13、转化生长因子β和脂联素等,在抑郁症中表达下降;补充外源抗炎性细胞因子则具有一定的抗抑郁作用.抗炎性细胞因子可通过拮抗前炎性细胞因子的作用,并与MAPK信号通路、神经递质和糖皮质激素相互作用而参与到抑郁症中.抗抑郁药能使抗炎性细胞因子的表达上升,这可能是药物起效的机制之一.抗炎策略在抑郁症的治疗中有重要应用前景.     

谷氨酸循环障碍与抑郁症

抑郁症是当今社会较多发的严重影响人类生活质量的疾病,迄今为止,抑郁症病因与发病机制还不完全明确,在过去的很多年,单胺类神经递质假说一直处在相对重要的位置,然而,近年越来越多的临床证据表明,单胺类递质假说并不能完全解释抑郁症的发病机制与其所起到的治疗作用,是否还有另一种机制参与其中呢?近期大量实验研究表明谷氨酸能系统在抑郁症的发病及治疗中扮演了重要的角色,本文就谷氨酸能系统在抑郁症的发病及治疗中发挥的疗效作用综述如下。     

谷氨酸循环障碍与抑郁症

抑郁症是当今社会较多发的严重影响人类生活质量的疾病,迄今为止,抑郁症病因与发病机制还不完全明确,在过去的很多年,单胺类神经递质假说一直处在相对重要的位置,然而,近年越来越多的临床证据表明,单胺类递质假说并不能完全解释抑郁症的发病机制与其所起到的治疗作用,是否还有另一种机制参与其中呢？近期大量实验研究表明谷氨酸能系统在抑郁症的发病及治疗中扮演了重要的角色,本文就谷氨酸能系统在抑郁症的发病及治疗中发挥的疗效作用综述如下。     

树鼩模型在人类病毒性疾病研究中的应用进展

由于树鼩在进化上接近于灵长类动物,在生理、生化及解剖学等生物学特性方面与人类有着相似之处,树鼩得到越来越多的关注,研究人员运用与其他动物相比具有多种优势的树鼩建立了一系列的疾病模型,如病毒类疾病、神经系统、肿瘤等,本文着重就树鼩在人类病毒疾病方面的研究进展进行概述。     

综述与专论: 树鼩病毒感染模型的研究新进展

病毒感染引起的疾病接近中国主要传染病发病率的一半,也是传染病致死的主要病因。建立与人类亲缘关系较近、方便有效的感染人类病毒的动物模型,对了解病毒的生物学特性、感染致病机理及制定有效防控措施具有重要意义。树鼩作为灵长类动物的近亲,与人类在生理生化、基因组学等方面的相似性远高于大鼠、小鼠等常用啮齿类实验动物,并具有个体小、便于实验操作、饲养成本低、能感染多种人类病毒等特点,作为动物模型在病毒感染性疾病研究中突显优势和潜能。本文从地区分布、进化、生物学特性等方面,阐述了树鼩作为动物模型应用于病毒感染性疾病研究的优势,包括在乙型肝炎病毒、甲型肝炎病毒,及其他病毒感染疾病研究中的进展。     

动物模型与人类疾病机理重点实验室成功破译树鼩基因组

由中科院昆明动物所动物模型与人类疾病机理重点实验室、深圳华大基因研究院等单位合作完成的破译树鼩基因组研究工作于2013年2月在《自然·通讯》(Nature Communications)杂志上在线发表。研究人员通过完成高质量的树鼩(Tupaia belangeri chinensis)全基因组测序及比较基因组分析,阐明了其系统分类地位和相关生物学特征的遗传基础,尤其是树鼩用于若干重要疾病如HBV、HCV感染以及抑郁症模     

树鼩干扰素家族的基本构成及分子特征分析

干扰素(IFN)是在"危险信号"刺激下,由细胞分泌的具有抗病毒、抗肿瘤、抑制细胞增殖和免疫调节等多重作用的糖蛋白家族,在机体免疫系统中具有重要地位。树鼩作为多种人类疾病研究模型的前景已受到广泛关注,但对其IFN家族的研究尚属空白。该研究在现有的树鼩全基因组数据基础上,应用大片段核酸序列比对、基因预测等方法,对树鼩IFN家族的基本构成和分子特征进行预测和分析。结果显示,树鼩具有I型IFN:α(5个亚型)、β、ω、κ、ε、δ;II型IFN-γ;III型IFN:IFN-λ1、λ2/3,所编码的氨基酸序列及蛋白空间结构与其它哺乳动物具有较高的相似性,但在半胱氨酸位置和N糖基化个数上具有部分差异。该研究以全基因组数据对树鼩IFN家族信息进行系统挖掘和分析,为树鼩IFN的基因克隆以及其在感染免疫学中的作用和机理研究奠定了基础。     

Extensive characterization of Tupaia belangeri neuropeptidome using an integrated mass spectrometric approach

Neuropeptidomics is used to characterize endogenous peptides in the brain of tree shrews (Tupaia belangeri). Tree shrews are small animals similar to rodents in size but close relatives of primates, and are excellent models for brain research. Currently, tree shrews have no complete proteome information available on which direct database search can be allowed for neuropeptide identification. To increase the capability in the identification of neuropeptides in tree shrews, we developed an integrated mass spectrometry (MS)-based approach that combines methods including data-dependent, directed, and targeted liquid chromatography (LC)-Fourier transform (FT)-tandem MS (MS/MS) analysis, database construction, de novo sequencing, precursor protein search, and homology analysis. Using this integrated approach, we identified 107 endogenous peptides that have sequences identical or similar to those from other mammalian species. High accuracy MS and tandem MS information, with BLAST analysis and chromatographic characteristics were used to confirm the sequences of all the identified peptides. Interestingly, further sequence homology analysis demonstrated that tree shrew peptides have a significantly higher degree of homology to equivalent sequences in humans than those in mice or rats, consistent with the close phylogenetic relationship between tree shrews and primates. Our results provide the first extensive characterization of the peptidome in tree shrews, which now permits characterization of their function in nervous and endocrine system. As the approach developed fully used the conservative properties of neuropeptides in evolution and the advantage of high accuracy MS, it can be portable for identification of neuropeptides in other species for which the fully sequenced genomes or proteomes are not available.     

Chronic Clomipramine Treatment Reverses Core Symptom of Depression in Subordinate Tree Shrews

Chronic stress is the major cause of clinical depression. The behavioral signs of depression, including anhedonia, learning and memory deficits, and sleep disruption, result from the damaging effects of stress hormones on specific neural pathways. The Chinese tree shrew (Tupaia belangeri chinensis) is an aggressive non-human primate with a hierarchical social structure that has become a well-established model of the behavioral, endocrine, and neurobiological changes associated with stress-induced depression. The tricyclic antidepressant clomipramine treats many of the core symptoms of depression in humans. To further test the validity of the tree shrew model of depression, we examined the effects of clomipramine on depression-like behaviors and physiological stress responses induced by social defeat in subordinate tree shrews. Social defeat led to weight loss, anhedonia (as measured by sucrose preference), unstable fluctuations in locomotor activity, sustained urinary cortisol elevation, irregular cortisol rhythms, and deficient hippocampal long-term potentiation (LTP). Clomipramine ameliorated anhedonia and irregular locomotor activity, and partially rescued the irregular cortisol rhythm. In contrast, weight loss increased, cortisol levels were even higher, and in vitro LTP was still impaired in the clomipramine treatment group. These results demonstrate the unique advantage of the tree shrew social defeat model of depression.     

Mutations in the p53 tumor suppressor gene in tree shrew hepatocellular carcinoma associated with hepatitis B virus infection and intake of aflatoxin B1

Infection with hepadnaviruses and exposure to aflatoxin B1 (AFB1) are considered to be major risk factors in the development of hepatocellular carcinoma (HCC) in humans. A high rate of p53 mutations at codon 249 has been reported in these tumors. The tree shrew (Tupaia belangeri chinensis) is a useful animal model for the development of HCC after human hepatitis B virus (HBV) infection or AFB1 treatment. Therefore, it was of particular interest to determine whether the p53 gene in tree shrew HCCs associated with HBV infection and/or with exposure to AFB1 is affected in the same manner as in human HCCs. We determined the tree shrew p53 wild-type nucleotide sequences by RT-PCR and automatic DNA-sequencing. Tree shrew wild-type p53 sequence showed 91.7 and 93.4% homologies with human p53 nucleotide and amino acids sequences, respectively, while it showed 77.2 and 73.7% homologies in mice. One HCC and normal liver tissue from AFB1 treated and one HCC from AFB1- and HBV-treated tree shrew showed no change in p53 sequences, while three HCCs from AFB1- and HBV-treated tree shrews showed point mutations in p53 sequences. One HCC showed point mutations at codon 275, which is on the DNA-binding domain of p53 gene, which might be a cause of gain-of-function during the development of HCC. As a result, our finding indicates that tree shrews exposed to AFB1 and/or HBV had neither codon 249 mutations nor significant levels of other mutations in the p53 gene, as is the case with humans.     

树鼩模型:抑郁症的社会竞争失败与学习和记忆的被捕获条件反射

最近基因组研究表明树鼩属于灵长类或是与灵长类亲缘关系最密切的姐妹种.因此,树鼩可能是应用于建立人类疾病动物模型的最佳动物之一.该文报道一种抑郁症的社会竞争失败病因学树鼩(Tupaia belangerichinensis)模型.一对雄性树鼩被饲养在一个双笼中,用网格把双笼隔开,网格上有一小门.适应1周后,把小门打开,这一对树鼩产生短暂的争斗,每天一次,连续21天.其中争斗失败者被称为服从者.这个过程可导致每天1 h的直接社交冲突和23 h的间接相互影响(比如通过气味、视觉等).与正常对照相比,失败者在第三周也就是社交冲突的最后一周显示了体重、自主活动、躲避行为、尿液皮质醇水平等的变化,并且这种改变可持续至少2周以上.此外,还报道全新的记忆模型,一种被捕获条件反射树鼩模型.在一个封闭的小房间中放置捕获笼,其中挂有一片苹果,小房间中有一只自由活动的树鼩.训练的前4次树鼩进入捕获笼吃苹果并不触发捕获笼关闭,但在第5次时触发捕获笼关闭,并持续一小时才释放树鼩.第1-5次树鼩进入捕获笼的延迟时时间作为适心性指标,其中第5次才是作为被捕获的一次学习训练.24 h后,测试树鼩进入捕获笼的延迟时间作为被捕获记忆能力指标.树鼩经过第5次被捕获训练,能形成很好的被捕获记忆,因为24 h后的延迟时间极人地增加.在训练前腹腔注射已知能阻断记忆形成的NMDA受体拮抗剂MK-801(0.2 mg/kg,腹腔注射),对适应指标没有显著影响,但足极大地缩短了24 h后测试的延迟时间,即阻断了被捕获记忆.这些结果表明了一种抑郁症的慢性社会竞争失败与学习和记忆的一次被捕获条件反射树鼩模型.这两种树趵模型对抑郁症与学习和记忆的机理研究、抗抑郁症新药的临床前药效学评价具有潜在的重要意义.

Abstract：

Recent genome studies indicate that tree shrew is in the order or a closest sister of primates, and thus may be one of the best animals to model human diseases. In this paper, we report on a social defeat model of depression in tree shrew (Tupaia belangeri chinensis). Two male tree shrews were housed in a pair-cage consisting of two independent cages separated by a wire mesh partition with a door connecting the two cages. After one week adaptation, the connecting door was opened and a brief fighting occurs between the two male tree shrews and this social conflict session consisted of 1 h direct conflict (fighting) and 23 h indirect influence (e.g. smell, visual cues) per day for 21 days. The defeated tree shrew was considered the subordinate. Compared with naive animals, subordinate tree shrews at the final week of social conflict session showed alterations in body weight, locomotion, avoidance behavior and urinary cortisol levels.Remarkably, these alterations persisted for over two weeks. We also report on a novel captive conditioning model of learning and memory in tree shrew. An automatic trapping cage was placed in a small closed room with a freely-moving tree shrew. For the first four trials, the tree shrew was not trapped when it entered the cage and ate the bait apple, but it was trapped and kept in the cage for 1 h on the fifth trial. Latency was defined as the time between release of the tree shrew and when it entered the captive cage. Latencies during the five trials indicated adaptation. A test trial 24 h later was used to measure whether the one-trial trapping during the fifth trial could form captive memory. Tree shrews showed much longer trapping latencies in the test trial than the adaptation trials. The N-methyl-d-aspartate (NMDA) receptor antagonist MK-801 (0.2 mg/kg, i.p.), known to prevent the formation of memory, did not affect latencies in the adaptation trails, but did block captive memory as it led to much shorter trapping latencies compared to saline treatment in the test trial. These results demonstrate a chronic social defeat model of depression and a novel one-trial captive conditioning model for learning and memory in tree shrews, which are important for mechanism studies of depression, learning,memory, and preclinical evaluation for new antidepressants.     

Motor Function in MPTP-Treated Tree Shrews (Tupaia belangeri chinensis)

The tree shrew, a new experimental animal model, has been used to study a variety of diseases, especially diseases of the nervous system. 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) is the gold standard for toxin-based animal models of Parkinson’s disease (PD) because MPTP treatment replicates almost all of the pathological hallmarks of PD. Therefore, in this study, the effects of MPTP on the motor function of the tree shrew were examined. After five daily injections of a 3 mg/kg dose of MPTP, the motor function of MPTP-injected tree shrews decreased significantly, and the classic Parkinsonian symptoms of action and resting tremor, bradykinesia, posture abnormalities, and gait instability were observed in most MPTP-injected tree shrews. HPLC results also showed significantly reduced striatal dopamine and 3,4-dihydroxyphenylacetic acid levels in tree shrews after MPTP injection. Increased oxidative stress levels are usually considered to be the cause of dopaminergic neuron depletion in the presence of MPTP and were observed in the substantia nigra of MPTP-treated tree shrews, as indicated by a significant reduction in superoxide dismutase and glutathione peroxidase activity and increased levels of malondialdehyde. In addition, elevated α-synuclein mRNA levels in the midbrain of MPTP-treated tree shrews were observed. Furthermore, MPTP-treated tree shrews showed the classic Parkinsonian symptoms at a lower MPTP dosage compared with other animal models. Thus, the MPTP-treated tree shrew may be a potential animal model for studying the pathogenesis of PD.     

Experimental chronic hepatitis B infection of neonatal tree shrews (Tupaia belangeri chinensis): A model to study molecular causes for susceptibility and disease progression to chronic hepatitis in humans

ABSTRACT: BACKGROUND: Hepatitis B virus (HBV) infection continues to be an escalating global health problem. Feasible and effective animal models for HBV infection are the prerequisite for developing novel therapies for this disease. The tree shrew (Tupaia) is a small animal species evolutionary closely related to humans, and thus is permissive to certain human viral pathogens. Whether tree shrews could be chronically infected with HBV in vivo has been controversial for decades. Most published research has been reported on adult tree shrews, and only small numbers of HBV infected newborn tree shrews had been observed over short time periods. We investigated susceptibility of newborn tree shrews to experimental HBV infection as well as viral clearance over a protracted time period. RESULTS: Forty-six newborn tree shrews were inoculated with the sera from HBV-infected patients or tree shrews. Serum and liver samples of the inoculated animals were periodically collected and analyzed using fluorescence quantitative polymerase chain reaction, enzyme-linked immunosorbent assay, Southern blot, and immunohistochemistry. Six tree shrews were confirmed and four were suspected as chronically HBV-infected for more than 48 (up to 228) weeks after inoculation, including three that had been inoculated with serum from a confirmed HBV-infected tree shrew. CONCLUSIONS: Outbred neonatal tree shrews can be long-term chronically infected with HBV at a frequency comparable to humans. The model resembles human disease where also a smaller proportion of infected individuals develop chronic HBV related disease. This model might enable genetic and immunologic investigations which would allow determination of underlying molecular causes favoring susceptibility for chronic HBV infection and disease establishment vs. viral clearance.     

中国树鼩实验动物化研究进展和展望

该文回顾了我国树鼩驯养繁殖和研究的发展历史,介绍了树鼩实验动物化研究的最新进展,并结合我国目前的状况,提出了今后的工作建议:加强实验树鼩标准化(包括地方和国家标准)的研究、近交系动物的研制、达到商业化树鼩的基础分子与细胞生物学研究工具的研制、人类重大疾病树鼩动物模型研究和建设国家实验树鼩种源基地等。     

自发性树鼩乳腺肿瘤的特性(英文)

乳腺癌是严重危害女性健康的常见恶性肿瘤,建立合适的乳腺癌动物模型对于研究人类乳腺癌的生物学机制及发展新的防治方法至关重要。相对于常用的啮齿类动物,树鼩(Tupaia belangeri chinensis,tree shrew)因在进化层次上更接近于人类而可用于建立更适合的乳腺癌模型。该文详细了介绍一例树鼩自发性乳头状良性乳腺肿瘤。免疫组化结果显示该例肿瘤孕激素受体阳性且Ki-67阳性细胞比例显著增加;而活化的Caspase3阳性细胞比例较低;且肿瘤的形态和病理与人导管内乳头状肿瘤非常接近。提示利用树鼩建立乳腺肿瘤模型的可行性。     

Proteomic characteristics of the liver and skeletal muscle in the Chinese tree shrew (Tupaia belangeri chinensis)

Valid animal models are useful for studying the pathophysiology of specific disorders, such as neural disease, diabetes and cancer. Previous molecular phylogeny studies indicate that the tree shrew is in the same order as (or a close sister to) primates, and thus may be an ideal model in which to study human disease. In this study, the proteome of liver and muscle tissue in tree the shrew was identified by combining peptide fractionation and LC-MS/MS identification. In total, 2146 proteins were detected, including 1759 proteins in liver samples and 885 proteins in skeletal muscle samples from the tree shrew. Further sub-source analysis revealed that nearly half of the identified proteins (846 proteins and 418 proteins) were derived from human database. In this study, we are the first to describe the characteristics of the proteome from the liver and skeletal muscle of the tree shrew. Phylogenetic tree analysis based on these proteomic data showed that the tree shrew is closer to primates (human) than to glires (the mouse and rat).