cDNA

cDNA
  • 文章类型: Journal Article
    日本脑炎病毒(JEV),由蚊子传播的黄病毒,在亚洲国家引起了流行病和严重的神经系统疾病。在这项研究中,我们开发了一个cDNA感染性克隆,使用细菌人工染色体(BAC)载体的JEV基因型3菌株(EF571853.1)的pBACJYJEV3。将构建的感染性克隆转染到Vero细胞中,它表现出类似于亲本病毒的感染性和诱导的细胞病变效应。共聚焦显微镜证实了JEV包膜蛋白的表达。生长动力学的比较分析揭示了亲本和重组病毒之间相似的复制动力学,感染后72小时观察到峰值滴度(HPI)。此外,噬菌斑试验证明了病毒之间具有可比性的噬菌斑大小和形态。低温电子显微镜证实产生了与亲本病毒相同形态的重组病毒颗粒。使用灭活的亲本和重组病毒在小鼠中进行的免疫研究显示出强大的IgG反应,中和抗体产量随时间增加。这些结果展示了重组JEV3病毒的成功产生和表征,并为进一步研究JEV发病机理和疫苗开发提供了平台。
    Japanese encephalitis virus (JEV), a flavivirus transmitted by mosquitoes, has caused epidemics and severe neurological diseases in Asian countries. In this study, we developed a cDNA infectious clone, pBAC JYJEV3, of the JEV genotype 3 strain (EF571853.1) using a bacterial artificial chromosome (BAC) vector. The constructed infectious clone was transfected into Vero cells, where it exhibited infectivity and induced cytopathic effects akin to those of the parent virus. Confocal microscopy confirmed the expression of the JEV envelope protein. Comparative analysis of growth kinetics revealed similar replication dynamics between the parental and recombinant viruses, with peak titers observed 72 h post-infection (hpi). Furthermore, plaque assays demonstrated comparable plaque sizes and morphologies between the viruses. Cryo-electron microscopy confirmed the production of recombinant virus particles with a morphology identical to that of the parent virus. Immunization studies in mice using inactivated parental and recombinant viruses revealed robust IgG responses, with neutralizing antibody production increasing over time. These results showcase the successful generation and characterization of a recombinant JEV3 virus and provide a platform for further investigations into JEV pathogenesis and vaccine development.
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  • 文章类型: Journal Article
    低出生体重(LBW)这是非传染性疾病终生的危险因素,是一个重大的公共卫生问题。除了调节骨髓细胞的分化和增殖,被鉴定为生长因子独立性-1(GFI-1)的转录抑制因子对于造血干细胞维持和自我更新至关重要.本研究旨在比较GFI-1基因在LBW新生儿和正常出生体重(NBW)新生儿造血干细胞分化中的表达。方法在印度北部的三级护理中心获得研究所伦理委员会的批准后,于2019年9月至2021年9月进行了一项前瞻性比较分析研究。使用定量实时聚合酶链反应(RT-PCR)测量了50例足月妊娠和LBW新生儿(<2500克)的脐带血样本中的GFI-1基因表达水平,并与50例足月妊娠和NBW新生儿(≥2500克)的脐带血样本中的基因表达水平进行了比较。使用IBMSPSS统计软件24.0版(IBMCorp.,Armonk,NY).结果GFI-1在LBW新生儿中的表达中位数为3.1,而在NBW新生儿中的表达中位数为9.39。差异具有显著性(P<0.001)。LBW新生儿GFI-1基因表达水平与出生体重相关。发现相关系数为弱正(r=0.223)。NBW新生儿的出生体重与GFI-1基因的表达水平相关,呈正相关(r=0.332)。结论GFI-1基因水平与新生儿出生体重比较,呈弱正相关。将出生时GFI-1基因表达水平与NBW新生儿的出生体重进行比较,呈正相关。
    Introduction Low birth weight (LBW), which is a risk factor for noncommunicable diseases throughout life, is a significant public health concern. In addition to regulating myeloid cell differentiation and proliferation, a transcriptional repressor identified as growth factor independence-1 (GFI-1) is essential for hematopoietic stem cell maintenance and self-renewal. The current study was designed to compare the expression of the GFI-1 gene in the differentiation of hematopoietic stem cells in newborns with LBW and those with normal birth weight (NBW). Methods A prospective comparative analytical study was carried out from September 2019 to September 2021 after obtaining Institute Ethical Committee approval at a tertiary care center in north India. The GFI-1 gene expression levels in 50 cord blood samples from women with term gestation and LBW newborns (<2500 grams) were measured using quantitative real-time polymerase chain reaction (RT-PCR) and compared to gene expression levels in 50 cord blood samples from women with term gestation and NBW newborns (≥2500 grams). The data were analyzed using IBM SPSS statistics software version 24.0 (IBM Corp., Armonk, NY). Results The median GFI-1 expression in LBW newborns is 3.1, whereas among NBW newborns it is 9.39. The difference is significant (P <0.001). The level of GFI-1 gene expression in LBW newborns was correlated with their birth weight. The coefficient of correlation was found to be weakly positive (r = 0.223). The birth weight of NBW newborns was correlated to the level of expression of the GFI-1 gene, which was found to be positively correlated (r = 0.332). Conclusion The levels of the GFI-1 gene and newborn birth weight were compared in LBW infants, which were weakly positively correlated. The level of GFI-1 gene expression at birth was compared to the birth weight of NBW newborns, which was positively correlated.
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  • 文章类型: Journal Article
    高通量遗传筛选可用于发现触发特定细胞功能和/或表型的关键基因或基因序列。功能缺失遗传筛选主要通过RNA干扰(RNAi)实现,CRISPR敲除(CRISPRko),和CRISPR干扰(CRISPRI)技术。功能获得遗传筛选主要取决于cDNA文库的过表达和CRISPR激活(CRISPRa)。碱基编辑可以进行功能增益和功能丧失的遗传筛选。本文综述了基于Cas9核酸酶的遗传筛选技术,包括Cas9介导的基因组敲除和基于dCas9的基因激活和干扰。我们将这些方法与以前基于RNAi和cDNA文库过表达的遗传筛选技术进行了比较,并提出了CRISPR筛选的未来前景和应用。
    High-throughput genetic screening is useful for discovering critical genes or gene sequences that trigger specific cell functions and/or phenotypes. Loss-of-function genetic screening is mainly achieved through RNA interference (RNAi), CRISPR knock-out (CRISPRko), and CRISPR interference (CRISPRi) technologies. Gain-of-function genetic screening mainly depends on the overexpression of a cDNA library and CRISPR activation (CRISPRa). Base editing can perform both gain- and loss-of-function genetic screening. This review discusses genetic screening techniques based on Cas9 nuclease, including Cas9-mediated genome knock-out and dCas9-based gene activation and interference. We compare these methods with previous genetic screening techniques based on RNAi and cDNA library overexpression and propose future prospects and applications for CRISPR screening.
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  • 文章类型: Journal Article
    处理酸性气体的生物脱硫(BD)系统采用亲卤碱性硫氧化细菌的混合物将硫化物转化为元素硫。在过去的几年里,这些系统已经看到了重大的技术创新,导致微生物群落组成的变化。不同的研究已经确定并讨论了传统和改进系统中的微生物群落。然而,这些研究没有确定代谢活跃的社区成员,而仅仅关注成员的存在/不存在。因此,他们的结果不能证实某些细菌在BD系统中的活性和作用。为了调查活跃的社区成员,我们确定了中试规模BD系统的六个不同运行的微生物群落。使用DNA和RNA进行基于16SrRNA基因的扩增子测序。基于DNA和RNA的测序结果的比较鉴定了BD系统中的活性微生物。统计分析表明,并非所有现有的微生物都积极参与该系统,并且在操作过程中微生物群落不断进化。在跑步结束时,与Alkalilimnicolaehrlichii和硫碱性弧菌相关的菌株被确认为BD系统中最活跃的关键细菌。这项研究确定,微生物群落的形状主要由水力停留时间(HRT)和硫化物浓度的组合在缺氧反应器中,在较小程度上,其他操作参数。重要的嗜碱性硫氧化细菌是生物脱硫(BD)系统的组成部分,负责将硫化物转化为硫。要了解BD系统中发生转换的原因,知道哪些细菌在系统中存在和活跃是必不可少的。到目前为止,只有少数研究调查了BD系统的微生物组成,但是没有人发现活跃的微生物群落。这里,我们揭示了代谢活跃的社区,他们的继承,以及它们对产品形成的影响。
    Biodesulfurization (BD) systems that treat sour gas employ mixtures of haloalkaliphilic sulfur-oxidizing bacteria to convert sulfide to elemental sulfur. In the past years, these systems have seen major technical innovations that have led to changes in microbial community composition. Different studies have identified and discussed the microbial communities in both traditional and improved systems. However, these studies do not identify metabolically active community members and merely focus on members\' presence/absence. Therefore, their results cannot confirm the activity and role of certain bacteria in the BD system. To investigate the active community members, we determined the microbial communities of six different runs of a pilot-scale BD system. 16S rRNA gene-based amplicon sequencing was performed using both DNA and RNA. A comparison of the DNA- and RNA-based sequencing results identified the active microbes in the BD system. Statistical analyses indicated that not all the existing microbes were actively involved in the system and that microbial communities continuously evolved during the operation. At the end of the run, strains affiliated with Alkalilimnicola ehrlichii and Thioalkalivibrio sulfidiphilus were confirmed as the most active key bacteria in the BD system. This study determined that microbial communities were shaped predominantly by the combination of hydraulic retention time (HRT) and sulfide concentration in the anoxic reactor and, to a lesser extent, by other operational parameters.IMPORTANCEHaloalkaliphilic sulfur-oxidizing bacteria are integral to biodesulfurization (BD) systems and are responsible for converting sulfide to sulfur. To understand the cause of conversions occurring in the BD systems, knowing which bacteria are present and active in the systems is essential. So far, only a few studies have investigated the BD system\'s microbial composition, but none have identified the active microbial community. Here, we reveal the metabolically active community, their succession, and their influence on product formation.
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  • 文章类型: Journal Article
    无细胞RNA(cfRNA)是有希望的分析物作为非侵入性生物标志物,如果与代谢组学结合,则具有更大的潜力。血浆是cfRNA的最佳来源,但通常来自多种抗凝剂。在肝素中获得的血浆适用于代谢组学,但难以用于基于qPCR的下游分析。在本研究中,我们的目标是开发一个简单的,省时,和具有成本效益的肝素酶方案,随后进行文库制备和人血浆cfRNAs的测序,并在-80°C的肝素中储存数年。在美国国立卫生研究院(NIH)临床中心的患有慢性HCV感染(NCT02400216)的患者的CPT™肝素钠管中收集血液。血浆cfRNA用肝素酶I处理并用于文库制备和下一代测序(NGS)。肝素酶处理维持了RNA完整性,并允许即使以7ngcfRNA作为起始材料的所有研究受试者的成功文库制备。源自PavianR包v1.2.0的分类报告显示没有人工读数。微生物读数上的脊索酸盐丰度表明通过肝素酶I处理没有增加实验误差。我们报告了一种新颖实用的方法,用于在肝素钠中收集和冷冻数年的人血浆的肝素酶治疗。这是利用肝素血浆进行NGS和下游转录组学研究的有效证明,然后可以与来自相同样本的代谢组学整合,最大限度地提高效率和减少抽血。
    Cell-free RNAs (cfRNAs) are promising analytes as non-invasive biomarkers and have even greater potential if tied in with metabolomics. Plasma is an optimal source for cfRNAs but is often derived from a variety of anticoagulants. Plasma obtained in heparin is suitable for metabolomics but is difficult to utilize for qPCR-based downstream analysis. In the present study, we aimed to develop a simple, time-efficient, and cost-effective heparinase protocol, followed by library preparation and sequencing of human plasma cfRNAs drawn and stored in heparin at -80 °C for several years. Blood was collected in CPT™ sodium heparin tubes from patients with chronic HCV infection (NCT02400216) at the National Institutes of Health (NIH) Clinical Center. Plasma cfRNAs were treated with heparinase I and used for library preparation and next-generation sequencing (NGS). Heparinase treatment maintained RNA integrity and allowed for successful library preparation for all the study subjects even with 7 ng of cfRNAs as starting material. The classification report derived from Pavian R package v1.2.0 showed no artificial reads. The abundance of chordate over microbial reads suggests no addition of experimental error through heparinase I treatment. We report a novel and practical approach to heparinase treatment for human plasma collected and frozen in sodium heparin for several years. This is an effective demonstration of utilizing heparin plasma for NGS and downstream transcriptomic research, which could then be integrated with metabolomics from the same samples, maximizing efficiency and minimizing blood draws.
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  • 文章类型: Journal Article
    丙型肝炎病毒(HCV)是导致全球慢性肝病的病原体。它是一个小,随函附上,单链核糖核酸(RNA)病毒。致病性HCV基因型的识别对于其患者的治疗至关重要。这项研究的目的是确定HCVRNA基因型,以决定孟加拉国丙型肝炎阳性患者的正确治疗方法。从390个个体收集血液样品,并从血浆中分离RNA(60μg)。提取的RNA用于定量HCVRNA,通过逆转录酶进行的聚合酶链反应(PCR)制备互补DNA(cDNA)。该cDNA通过RT-PCR多重扩增,这是用特定的引物组进行的。390例患者中检测到297个HCVRNA基因型。在390个测试样本中,200份(51.28%)样本来自男性,190份(48.71%)来自女性,年龄从5岁到78岁不等。总之,发现200个男性样本中的166个和131个/190个女性样本的HCV阳性。在纳入研究的390名参与者中,213(54.61%)被鉴定为基因型3阳性,78(20%)为基因型1阳性,6(1.53%)为基因型6阳性,其余93份(23.85%)样本因病毒载量低/未检出而未分类.在这项研究中,在51~60岁的患者中,我们检测到基因型3HCV的比例最高(30.89%).结果表明,基因型3HCV在孟加拉国经常出现,通常对干扰素治疗反应更好。然而,基因型1和6的HCV也被发现在这个国家流行,这需要更长时间的治疗和有效的控制措施。
    Hepatitis C virus (HCV) is a causative agent that causes chronic liver diseases worldwide. It is a little, enclosed, single-stranded ribonucleic acid (RNA) virus. The recognition of the pathogenic HCV genotype is critical for the remedy of its sufferers. The aim of this study was to identify the HCV RNA genotype to decide the correct treatment of hepatitis C positive sufferers in Bangladesh. Blood samples were collected from 390 individuals and isolated RNA (60 µg) from blood plasma. Extracted RNA was used for quantitative HCV RNA, and complementary DNA (cDNA) was prepared by polymerase chain reaction (PCR) conducted by reverse transcriptase enzyme. This cDNA amplified in multiplex by RT-PCR, which was performed with specific set of primers. The HCV RNA genotype was detected 297 of 390 patients. Of the 390 test samples, 200 (51.28%) samples were from males and 190 (48.71%) were from females, with age ranging from 5 to 78 years. In all, 166 of 200 male samples and 131/190 female samples were found positive for HCV. Of these 390 participants included in the study, 213 (54.61%) were identified as genotype 3 positive, 78 (20%) as genotype 1 positive, 6 (1.53%) as genotype 6 positive, and the remaining 93 (23.85%) samples were unclassified due to low/undetected viral load. In this study, we detected the highest percentage (30.89%) of genotype 3 HCV in patients aged 51 to 60 years. The results suggested that genotype 3 HCV is frequently present in Bangladesh and it is usually responses better to interferon therapy. However, genotype 1 and 6 HCV have also been found circulating in this country, which demands longer treatments and effective control measures.
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  • 文章类型: Journal Article
    液体活检,作为一种非侵入性诊断工具,最近在肿瘤学领域获得了极大的关注。它涉及对体液中存在的各种生物标志物的分析,如血液或脑脊液,提供有关潜在癌症的信息。以WHO4级星形细胞瘤为例,液体活检有可能显著影响这种侵袭性恶性脑肿瘤的诊断和预后。通过检测特定的基因突变,如IDH1或EGFR,监测循环肿瘤DNA的水平,液体活检可以帮助早期发现和监测疾病进展。这种创新方法逐渐被认为是一种侵入性较低且具有成本效益的癌症诊断和管理程序,以改善患者的预后和生活质量。在脑脊液(CSF)中循环的各种生物标志物,如循环肿瘤细胞(CTC)和不同类型的核酸,如无细胞DNA(cfDNA),无细胞RNA(ctRNA),和microRNAs(miRNA),已被确认。这些生物标志物,这需要可靠的检测方法,相对容易获得,并允许重复测量,使它们明显优于疾病监测。这篇综述旨在比较中枢神经系统中CSF和血浆的最新液体活检分析工具。
    Liquid biopsy, as a non-invasive diagnostic tool, has recently gained significant attention in the field of oncology. It involves the analysis of various biomarkers present in bodily fluids, such as blood or cerebrospinal fluid, to provide information about the underlying cancer. In the case of WHO grade 4 astrocytomas, liquid biopsy has the potential to significantly impact the diagnosis and prognosis of this aggressive malignant brain tumor. By detecting specific genetic mutations, such as IDH1 or EGFR, and monitoring levels of circulating tumor DNA, liquid biopsy can aid in the early detection and monitoring of disease progression. This innovative approach is gradually being acknowledged as a less invasive and cost-effective procedure for cancer diagnosis and management to improve patient outcomes and quality of life. Various kinds of biomarkers circulating in cerebrospinal fluid (CSF), such as circulating tumor cells (CTC) and different types of nucleic acids like cell-free DNA (cfDNA), cell-free RNA (ctRNA), and microRNAs (miRNA), have been identified. These biomarkers, which require dependable detection methods, are comparatively simple to obtain and allow for repeated measurements, making them significantly superior for disease monitoring. This review aims to compare the latest liquid biopsy analysis tools for both CSF and plasma in the central nervous system.
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  • 文章类型: Journal Article
    细胞群体和组织表现出独特的基因表达谱,允许表征和区分细胞亚型。监测细胞类型特异性标志物的基因表达可以指示细胞状态,如增殖,压力,静止,或成熟。定量逆转录酶PCR(qRT-PCR)允许定量细胞类型特异性标志物的RNA表达并区分一种细胞类型与另一种细胞类型。然而,qRT-PCR方法(例如TaqMan技术)需要荧光报告基因来表征靶基因,并且难以扩大规模,因为它们需要不同的探针用于每个反应。大容量或单细胞RNA转录组学是耗时且昂贵的。处理RNA测序数据可能需要数周时间,这对于质量控制和监测基因表达不是最佳的,例如,在诱导多能干细胞(iPSC)分化为特化细胞类型的范例中。一种更具成本效益的测定法基于SYBRGreen技术。SYBRGreen是一种与双链DNA结合的核酸染料,吸收497nm的蓝光,并在插入双链DNA后在520nm处发出高达1,000倍的绿光。当相对于管家基因进行归一化并与对照条件进行比较时,可以基于荧光强度水平来定量感兴趣区域的扩增。以前,我们建立了SYBRGreenqRT-PCR方案,以使用涂布在96孔板上的一组有限的标记物表征样品。这里,我们优化了这个过程,增加了一个384孔格式的通量,并比较mRNA表达,以区分iPSC衍生的神经元亚型彼此通过增加基因的数量,细胞类型,和分化时间点。在这个协议中,我们开发了以下内容:i)使用Primer3软件的命令行版本,我们为感兴趣的基因更容易和快速地设计引物;ii)使用384孔板格式,电子多通道移液器,和移液机器人,我们在单个平板上分析了四倍多的基因,同时使用与96孔板相同体积的试剂。该方案的优点是增加了SYBRGreen测定的吞吐量,同时限制了移液错误/不一致,试剂使用,成本,和时间。图形概述。
    Cell populations and tissues exhibit unique gene expression profiles, which allow for characterizing and distinguishing cellular subtypes. Monitoring gene expression of cell type-specific markers can indicate cell status such as proliferation, stress, quiescence, or maturation. Quantitative reverse transcriptase PCR (qRT-PCR) allows quantifying RNA expression of cell type-specific markers and distinguishing one cell type from another. However, qRT-PCR methods such as TaqMan technology require fluorescent reporters to characterize target genes and are challenging to scale up as they need different probes for each reaction. Bulk or single-cell RNA transcriptomics is time-consuming and expensive. Processing RNA sequencing data can take several weeks, which is not optimal for quality control and monitoring gene expression, e.g., during a differentiation paradigm of induced pluripotent stem cells (iPSCs) into a specialized cell type. A more cost-effective assay is based on SYBR Green technology. SYBR Green is a nucleic acid dye that binds to double-stranded DNA, absorbs blue light at 497 nm, and emits green light at 520 nm up to 1,000-fold upon intercalation with double-stranded DNA. Amplification of a region of interest can be quantified based on the level of fluorescence intensity when normalized to a housekeeping gene and compared to control conditions. Previously, we established a SYBR Green qRT-PCR protocol to characterize samples using a limited set of markers plated on a 96-well plate. Here, we optimize the process and increase throughput to a 384-well format and compare mRNA expression to distinguish iPSC-derived neuronal subtypes from each other by increasing the number of genes, cell types, and differentiation time points. In this protocol, we develop the following: i) using the command-line version of Primer3 software, we design primers more easily and quickly for the gene of interest; ii) using a 384-well plate format, electronic multichannel pipettes, and pipetting robots, we analyze four times more genes on a single plate while using the same volume of reagents as in a 96-well plate. The advantages of this protocol are the increased throughput of this SYBR Green assay while limiting pipetting errors/inconsistencies, reagent use, cost, and time. Graphical overview.
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  • 文章类型: Journal Article
    人类基因组测序赋予了转化医学,促进全转录组分子诊断,通路生物学,和药物重新定位。最初,微阵列用于研究批量转录组;但现在短读RNA测序(RNA-seq)占主导地位。定位为一种卓越的技术,这使得发现小说转录本成为例行公事,大多数RNA-seq分析实际上是基于已知的转录组建模的。RNA-seq方法的局限性已经出现,而设计的,以及应用于的分析策略,数组已经成熟。提供了这些技术之间的公平比较,突出了现代阵列相对于RNA-seq的优势。阵列方案更准确地量化跨组织复制的组成型表达的蛋白质编码基因,并且对于研究较低表达的基因更可靠。阵列显示长非编码RNA(lncRNA)的表达既不稀疏也不低于蛋白质编码基因。用RNA-seq观察到的组成型表达基因的异质性覆盖,削弱了途径分析的有效性和可重复性。推动这些观察的因素,讨论了其中许多与长读或单细胞测序有关。如本文所述,需要重新评估批量转录组学方法,包括更广泛地使用现代高密度阵列数据来紧急修改现有的解剖学RNA参考图谱,并协助更准确地研究lncRNA。
    Sequencing the human genome empowers translational medicine, facilitating transcriptome-wide molecular diagnosis, pathway biology, and drug repositioning. Initially, microarrays are used to study the bulk transcriptome; but now short-read RNA sequencing (RNA-seq) predominates. Positioned as a superior technology, that makes the discovery of novel transcripts routine, most RNA-seq analyses are in fact modeled on the known transcriptome. Limitations of the RNA-seq methodology have emerged, while the design of, and the analysis strategies applied to, arrays have matured. An equitable comparison between these technologies is provided, highlighting advantages that modern arrays hold over RNA-seq. Array protocols more accurately quantify constitutively expressed protein coding genes across tissue replicates, and are more reliable for studying lower expressed genes. Arrays reveal long noncoding RNAs (lncRNA) are neither sparsely nor lower expressed than protein coding genes. Heterogeneous coverage of constitutively expressed genes observed with RNA-seq, undermines the validity and reproducibility of pathway analyses. The factors driving these observations, many of which are relevant to long-read or single-cell sequencing are discussed. As proposed herein, a reappreciation of bulk transcriptomic methods is required, including wider use of the modern high-density array data-to urgently revise existing anatomical RNA reference atlases and assist with more accurate study of lncRNAs.
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  • 文章类型: Journal Article
    溶酶体半胱氨酸蛋白酶组织蛋白酶B(CTSB)已被认为是阿尔茨海默病(AD)的生物标志物,因为AD患者血清CTSB升高与认知功能障碍有关。此外,非转基因和转基因AD动物模型中的CTSB基因敲除(KO)显示消除CTSB改善了记忆缺陷。然而,已经报道了转基因AD模型中淀粉样蛋白-β(Aβ)病理学的CTSBKO结果相互矛盾。冲突在此得到解决,因为可能是由于在不同AD小鼠模型中使用的不同hAβPP转基因。CTSB基因KO降低野生型(Wt)β分泌酶活性,大脑Aβ,焦谷氨酸-Aβ,淀粉样斑块,和使用表达hAβPP同种型695的cDNA转基因的模型中的记忆缺陷。但是在使用表达hAβPP同工型751和770的突变微型转基因的模型中,CTSBKO对Wtβ分泌酶活性没有影响,脑Aβ略有增加。所有模型都在神经元中表达转基因。Wtβ分泌酶活性模型中的这些矛盾结果可以通过hAβPP同工型特异性细胞表达来解释,蛋白水解,和亚细胞处理。在hAβPP695和hAβPP751/770模型中,CTSBKO对瑞典突变体(Swe)β分泌酶活性没有影响。Wt对hAβPP的蛋白水解敏感性不同。Sweβ分泌酶位点序列可以解释hAβPP695模型中CTSBβ分泌酶的不同作用。但由于绝大多数散发性AD患者具有Wtβ-分泌酶活性,CTSB对Sweβ-分泌酶活性的影响对一般AD人群并不重要。由于神经元自然产生和加工hAβPP同工型695,而不是751和770同工型,只有hAβPP695Wt模型模拟大多数AD患者中发生的天然神经元hAβPP加工和Aβ产生。重要的是,在hAβPP695Wt模型中的这些CTSBKO发现证明了CTSB参与记忆缺陷和焦谷氨酸-Aβ(pyroglu-Aβ)的产生,这为未来CTSB抑制剂在AD治疗开发中的研究提供了依据。
    The lysosomal cysteine protease cathepsin B (CTSB) has been suggested as a biomarker for Alzheimer\'s disease (AD) because elevated serum CTSB in AD patients has been found to correlate with cognitive dysfunction. Furthermore, CTSB gene knockout (KO) in non-transgenic and transgenic AD animal models showed that elimination of CTSB improved memory deficits. However, conflicting CTSB KO results on amyloid-β (Aβ) pathology in transgenic AD models have been reported. The conflict is resolved here as likely being due to the different hAβPP transgenes used in the different AD mouse models. CTSB gene KO reduced wild-type (Wt) β-secretase activity, brain Aβ, pyroglutamate-Aβ, amyloid plaque, and memory deficits in models that used cDNA transgenes expressing hAβPP isoform 695. But in models that used mutated mini transgenes expressing hAβPP isoforms 751 and 770, CTSB KO had no effect on Wt β-secretase activity and slightly increased brain Aβ. All models expressed the AβPP transgenes in neurons. These conflicting results in Wt β-secretase activity models can be explained by hAβPP isoform specific cellular expression, proteolysis, and subcellular processing. CTSB KO had no effect on Swedish mutant (Swe) β-secretase activity in hAβPP695 and hAβPP751/770 models. Different proteolytic sensitivities for hAβPP with Wt versus Swe β-secretase site sequences may explain the different CTSB β-secretase effects in hAβPP695 models. But since the vast majority of sporadic AD patients have Wt β-secretase activity, the CTSB effects on Swe β-secretase activity are of little importance to the general AD population. As neurons naturally produce and process hAβPP isoform 695 and not the 751 and 770 isoforms, only the hAβPP695 Wt models mimic the natural neuronal hAβPP processing and Aβ production occurring in most AD patients. Significantly, these CTSB KO findings in the hAβPP695 Wt models demonstrate that CTSB participates in memory deficits and production of pyroglutamate-Aβ (pyroglu-Aβ), which provide rationale for future investigation of CTSB inhibitors in AD therapeutics development.
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