PC12活细胞中单个分泌囊泡的动态成像

囊泡的荧光标记和动态显微成像观察是研究蛋白质和膜转运机制的重要手段。采用EGFP hpNPY融合荧光蛋白标记PC12细胞的致密大囊泡 ,用全内反射和宽场荧光显微镜对PC12细胞进行成像研究。结果发现 :普通的宽场荧光成像模糊不清 ,难以观察到单个囊泡 ;而全内反射荧光成像则可清晰地分辨出呈现为离散荧光点的单个囊泡 ;并且进一步利用全内反射荧光成像直接观察到了活的PC12细胞中单个囊泡的转运、锚定及与细胞膜的融合过程 ,证实了囊泡的锚定过程是可逆的。     

包封膜蛋白的仿生细胞膜

本文概述了脂质囊泡的组成成分和制作方法以及用于膜蛋白方面研究的相关技术,包括膜蛋白整合到囊泡的方法、复合体系的表征等。脂质囊泡可以为膜蛋白提供类似体内的环境,包括疏水区和内外亲水环境,因其组分单一,可以方便地进行结构、功能、信号转导等方面的研究,因此可以模拟细胞膜作为研究膜蛋白的有力工具,目前大多是以脂质体形态作为仿生囊泡体系进行这方面研究。     

高分子囊泡在药物释放体系的应用

高分子囊泡作为一种新型的纳米药物载体,具有生物可降解性、稳定性、生物相容性及可修饰的多功能化等特点。改变聚合物种类和亲水-疏水嵌段的比例,可以制备具有不同形态和膜特性的高分子囊泡。经过修饰后的高分子囊泡,可赋予其更多的功能,从而实现药物的控释和药物靶向的能力。对高分子囊泡的结构、组成和制备方法以及在药物释放体系的应用等方面进行了较为详细的综述,目的是了解高分子囊泡最新研究进展以及未来科学家们亟须解决的重要问题。     

时间序列荧光图像中精确检测高密度快速运动多囊泡的“自校正”算法

本文提出了一种“自校正”算法,用于提高时间序列荧光图像中的多个运动目标识别的正确率(如囊泡)．此算法的主要思想是构建一个由核函数叠加构成的模型,然后用这个模型去拟合无法分辨时刻的数据,通过最小二乘拟合后得到的模型与真实数据的χ²统计残差及拟合得到的核函数的参数,来确定该时刻囊泡的数目及各囊泡的中心位置．我们在合成图像上比较加入了自校正算法和未加自校正算法的识别正确率,结果表明,加入了自检算法以后识别正确率得到了明显提高．同时,提出了一个优化的囊泡追踪流程,并应用到小鼠β细胞的囊泡荧光图像分析中．统计分析显示,加入葡萄糖刺激后,小鼠β细胞囊泡轨迹数目会增加,平均锚定时间会减少,这是由于胰岛细胞需要借助囊泡的转运和分泌来调控血糖平衡．因此我们进一步在亚细胞水平定量分析了活细胞中囊泡的活动．     

细胞外囊泡研究进展

由细胞释放到细胞外环境中的来源于内体和细胞膜的多样化的膜性囊泡,统称为细胞外囊泡。这些细胞外囊泡作为细胞间转运膜和可溶性蛋白、脂质、RNA的载体,代表一种重要的细胞间通讯方式。虽然很多报道证明,多种细胞释放细胞外囊泡,并且具有一定的生理意义,但是我们目前缺乏对细胞外囊泡分子机制的深入理解,在细胞外囊泡研究的方法学以及人为调控细胞外囊泡的释放等方面也存在局限性,因此使得我们对它们在体内的生理学功能和细胞外囊泡作为疾病靶标的转化医学的研究进程缓慢。在这篇综述中,该文主要从细胞外囊泡的分类、分子细胞生物学研究、生理及病生理功能、细胞外囊泡的研究方法几个方面回顾当前细胞外囊泡领域的研究进展。     

UNC-10在致密核心囊泡分泌过程中的作用

Rim是囊泡分泌活性区中的重要组成蛋白,它与细胞分泌和突触可塑性相关．在秀丽隐感线虫中只存在一种编码Rim的基因即unc-10．我们的研究发现,在线虫中Rim的基因突变unc-10(md1117)会导致致密核心囊泡的分泌缺陷．在活体中,unc-10突变虫系的神经多肽分泌显著下降．此外,在主要分泌致密核心囊泡的ALA神经元内,钙光解释放促发的快相分泌也比野生型减少．运用全内反射荧光显微成像技术,我们观察在unc-10缺失的情况下ALA 神经元中致密核心囊泡的锚定过程,结果显示在细胞膜附近停留的囊泡数目减少,表明囊泡锚定受到阻碍．上述试验结果表明,UNC-10能够影响致密核心囊泡的分泌过程,其机制可能是影响了囊泡的锚定过程．     

细胞外囊泡表面蛋白冠的研究进展

细胞外囊泡是细胞释放的具有磷脂双层膜结构的天然纳米颗粒,参与体内细胞信号转导、肿瘤发生发展、免疫调节、延缓衰老等多种生理病理过程,在疾病诊断及治疗中表现出巨大潜力。既往研究认为,高纯度细胞外囊泡的制备易受杂质蛋白污染,制约了细胞外囊泡在生物标志物和药物运载系统方面的研究及转化应用。近两年,部分学者将合成纳米颗粒领域的蛋白冠这一概念引入细胞外囊泡领域,认为蛋白冠是细胞外囊泡表面的固有成分,并显著影响细胞外囊泡的生物学功能,为细胞外囊泡研究提供了新思路。概述了当前细胞外囊泡表面蛋白冠的研究现状,围绕该蛋白冠的形成过程、化学组成、生物功能、鉴定方法等展开,以期为细胞外囊泡及其蛋白冠的进一步研究提供参考。     

细菌外膜囊泡在疫苗领域的研究进展

细菌外膜囊泡是一种主要由革兰阴性菌在其生长过程中正常分泌的球状物质。这种球状小泡在细菌的生存和信息传递中起到了重要的作用。同时,由于这种球状小泡携带大量的细菌毒力相关蛋白,并且不具有复制的能力。因此,是一种良好的潜在疫苗候选抗原。目前,关于细菌外膜囊泡的构成成分、分泌机制、生物学作用等方面的研究已非常广泛。同时,利用细菌外膜囊泡作为主要抗原的疫苗产品也已面世。现就细菌外膜囊泡的结构研究以及细菌外膜囊泡在疫苗领域的研究作一概述,以期为进一步推动细菌外膜囊泡疫苗的研发提供更多的参考。     

时间序列荧光图像中精确检测高密度快速运动多囊泡的“自校正”算法（英文）

本文提出了一种"自校正"算法,用于提高时间序列荧光图像中的多个运动目标识别的正确率(如囊泡).此算法的主要思想是构建一个由核函数叠加构成的模型,然后用这个模型去拟合无法分辨时刻的数据,通过最小二乘拟合后得到的模型与真实数据的χ~2统计残差及拟合得到的核函数的参数,来确定该时刻囊泡的数目及各囊泡的中心位置.我们在合成图像上比较加入了自校正算法和未加自校正算法的识别正确率,结果表明,加入了自检算法以后识别正确率得到了明显提高.同时,提出了一个优化的囊泡追踪流程,并应用到小鼠β细胞的囊泡荧光图像分析中.统计分析显示,加入葡萄糖刺激后,小鼠β细胞囊泡轨迹数目会增加,平均锚定时间会减少,这是由于胰岛细胞需要借助囊泡的转运和分泌来调控血糖平衡.因此我们进一步在亚细胞水平定量分析了活细胞中囊泡的活动.     

细胞内的精密“物流”——以高中生物学为背景解读2013年诺贝尔生理学或医学奖

以高中生物学知识为背景,对获得2013年诺贝尔生理学或医学奖的3位科学家在细胞内囊泡转运方面的研究进行了形象地解读,主要包括兰迪·谢克曼关于囊泡分类与运输路径的研究,詹姆斯·罗斯曼的SNARE学说,以及托马斯·苏德霍夫关于囊泡转运物质释放信号控制的研究,并阐述了细胞内囊泡转运对人类健康的重要意义。尝试运用平实、形象的科普语言解读生命科学领域的最新研究成果,便于中学生了解生命科学发展的最前沿动态。     

Local drug and gene delivery through microbubbles and ultrasound

Although gene therapy has great potential as a treatment for diseases, clinical trials are slowed down by the development of a safe and efficient gene delivery system. In this review, we will give an overview of the viral and nonviral vehicles used for drug and gene delivery, and the different nonviral delivery techniques, thereby focusing on delivery through ultrasound contrast agents.The development of ultrasound contrast agents containing encapsulated microbubbles has increased the possibilities not only for diagnostic imaging, but for therapy as well. Microbubbles have been shown to be able to carry drugs and genes, and destruction of the bubbles by ultrasound will result in local release of their contents. Furthermore, ligands can be attached so that they can be targeted to a specific target tissue. The recent advances of microbubbles as vehicles for delivery of drugs and genes will be highlighted.     

Carrier-mediated delivery of peptidic drugs for cancer therapy

Protein and peptide drugs are used for treatment of a variety of ailments. However, their wider use has been hindered by issues such as poor bioavailability in vivo and the cost involved in producing these drugs. This review discusses the various carrier-mediated methods used for delivery of peptide and protein drugs, with emphasis on liposomal and microspherical drug delivery systems. A brief look at the types of peptidic drugs currently in use clinically, and a brief discourse on several novel ideas for better protein delivery systems for cancer therapy is included.     

Plant protein-based hydrophobic fine and ultrafine carrier particles in drug delivery systems

For thousands of years, plants and their products have been used as the mainstay of medicinal therapy. In recent years, besides attempts to isolate the active ingredients of medicinal plants, other new applications of plant products, such as their use to prepare drug delivery vehicles, have been discovered. Nanobiotechnology is a branch of pharmacology that can provide new approaches for drug delivery by the preparation of biocompatible carrier nanoparticles (NPs). In this article, we review recent studies with four important plant proteins that have been used as carriers for targeted delivery of drugs and genes. Zein is a water-insoluble protein from maize; Gliadin is a 70% alcohol-soluble protein from wheat and corn; legumin is a casein-like protein from leguminous seeds such as peas; lectins are glycoproteins naturally occurring in many plants that recognize specific carbohydrate residues. NPs formed from these proteins show good biocompatibility, possess the ability to enhance solubility, and provide sustained release of drugs and reduce their toxicity and side effects. The effects of preparation methods on the size and loading capacity of these NPs are also described in this review.     

Liposomes targeting tumour stromal cells

Liposomes have found clinical application in cancer therapy in the delivery of cytostatic agents. As a result of the targeted delivery of these toxic molecules to the tumour cells coupled to avoidance of toxicity-sensitive tissues, the therapeutic window is widened. Over the past years the focus of cancer therapy has shifted towards the stromal cells that are present in the tumour. It appears that clinically relevant tumours have acquired the ability to modulate the microenvironment in such a way that a chronic pro-inflammatory and pro-angiogenic state is achieved that contributes to invasion and metastasis and continued proliferation. Over the past years, liposomal formulations have been designed that target key stromal cell types that contribute to tumour growth. At the same time, many promising cell types have not been targeted yet and most of the studies employ drugs that aim at depleting stromal cells rather than modulating their activity towards an anti-tumour phenotype. In this review these target cell types will be addressed. Complementing these targeted formulations with the appropriate drugs to optimally suppress tumour-promoting signals while preserving anti-tumour action will be the challenge for the future.     

Carbon nanotubes in cancer diagnosis and therapy

During the past years, great progress has been made in the field of nanomaterials given their great potential in biomedical applications. Carbon nanotubes (CNTs), due to their unique physicochemical properties, have become a popular tool in cancer diagnosis and therapy. They are considered one of the most promising nanomaterials with the capability of both detecting the cancerous cells and delivering drugs or small therapeutic molecules to these cells. Over the last several years, CNTs have been explored in almost every single cancer treatment modality, including drug delivery, lymphatic targeted chemotherapy, thermal therapy, photodynamic therapy, and gene therapy. In this review, we will show how they have been introduced into the diagnosis and treatment of cancer. Novel SWNT-based tumor-targeted drug delivery systems (DDS) will be highlighted. Furthermore, the in vitro and in vivo toxicity of CNTs reported in recent years will be summarized.     

Proteins and their functionalization for finding therapeutic avenues in cancer: Current status and future prospective

Despite the remarkable advancement in the health care sector, cancer remains the second most fatal disease globally. The existing conventional cancer treatments primarily include chemotherapy, which has been associated with little to severe side effects, and radiotherapy, which is usually expensive. To overcome these problems, target-specific nanocarriers have been explored for delivering chemo drugs. However, recent reports on using a few proteins having anticancer activity and further use of them as drug carriers have generated tremendous attention for furthering the research towards cancer therapy. Biomolecules, especially proteins, have emerged as suitable alternatives in cancer treatment due to multiple favourable properties including biocompatibility, biodegradability, and structural flexibility for easy surface functionalization. Several in vitro and in vivo studies have reported that various proteins derived from animal, plant, and bacterial species, demonstrated strong cytotoxic and antiproliferative properties against malignant cells in native and their different structural conformations. Moreover, surface tunable properties of these proteins help to bind a range of anticancer drugs and target ligands, thus making them efficient delivery agents in cancer therapy. Here, we discuss various proteins obtained from common exogenous sources and how they transform into effective anticancer agents. We also comprehensively discuss the tumor-killing mechanisms of different dietary proteins such as bovine α-lactalbumin, hen egg-white lysozyme, and their conjugates. We also articulate how protein nanostructures can be used as carriers for delivering cancer drugs and theranostics, and strategies to be adopted for improving their in vivo delivery and targeting. We further discuss the FDA-approved protein-based anticancer formulations along with those in different phases of clinical trials.     

Advanced strategies in liposomal cancer therapy: problems and prospects of active and tumor specific drug release

Tumor specific drug delivery has become increasingly interesting in cancer therapy, as the use of chemotherapeutics is often limited due to severe side effects. Conventional drug delivery systems have shown low efficiency and a continuous search for more advanced drug delivery principles is therefore of great importance. In the first part of this review, we present current strategies in the drug delivery field, focusing on site-specific triggered drug release from liposomes in cancerous tissue. Currently marketed drug delivery systems lack the ability to actively release the carried drug and rely on passive diffusion or slow non-specific degradation of the liposomal carrier. To obtain elevated tumor-to-normal tissue drug ratios, it is important to develop drug delivery strategies where the liposomal carriers are actively degraded specifically in the tumor tissue. Many promising strategies have emerged ranging from externally triggered light- and thermosensitive liposomes to receptor targeted, pH- and enzymatically triggered liposomes relying on an endogenous trigger mechanism in the cancerous tissue. However, even though several of these strategies were introduced three decades ago, none of them have yet led to marketed drugs and are still far from achieving this goal. The most advanced and prospective technologies are probably the prodrug strategies where non-toxic drugs are carried and activated specifically in the malignant tissue by overexpressed enzymes. In the second part of this paper, we review our own work, exploiting secretory phospholipase A2 as a site-specific trigger and prodrug activator in cancer therapy. We present novel prodrug lipids together with biophysical investigations of liposome systems, constituted by these new lipids and demonstrate their degradability by secretory phospholipase A2. We furthermore give examples of the biological performance of the enzymatically degradable liposomes as advanced drug delivery systems.     

经皮给药纳米载体及靶向系统治疗类风湿关节炎研究进展

类风湿关节炎(RA)是全世界难治性自身免疫疾病,其治疗药物虽不断发展,但病灶药物浓度达不到有效水平导致药物疗效不理想或存在各种毒副反应,因此,基于新技术、新方法研究开发针对RA的安全、高效新型制剂是必要的.研究表明,纳米技术的运用可提高药物生物利用度,经皮给药可改善口服和注射带来的毒副作用.对近年来基于经皮给药系统治疗...     

Liposomes targeting tumour stromal cells

Abstract

Liposomes have found clinical application in cancer therapy in the delivery of cytostatic agents. As a result of the targeted delivery of these toxic molecules to the tumour cells coupled to avoidance of toxicity-sensitive tissues, the therapeutic window is widened. Over the past years the focus of cancer therapy has shifted towards the stromal cells that are present in the tumour. It appears that clinically relevant tumours have acquired the ability to modulate the microenvironment in such a way that a chronic pro-inflammatory and pro-angiogenic state is achieved that contributes to invasion and metastasis and continued proliferation. Over the past years, liposomal formulations have been designed that target key stromal cell types that contribute to tumour growth. At the same time, many promising cell types have not been targeted yet and most of the studies employ drugs that aim at depleting stromal cells rather than modulating their activity towards an anti-tumour phenotype. In this review these target cell types will be addressed. Complementing these targeted formulations with the appropriate drugs to optimally suppress tumour-promoting signals while preserving anti-tumour action will be the challenge for the future.