穿膜肽的研究进展

穿膜肽是一些具有细胞膜穿透能力的小分子多肽,可有效携带比其分子质量大100倍的外源性疏水大分子进入细胞,并对宿主细胞没有显著毒副作用.穿膜肽存在多种穿膜机制,诸如直接渗透到细胞膜,通过易位形成的一个暂时性的结构和内吞作用介导入膜等.具体的穿膜机制还不清楚,但普遍认为穿膜肽与细胞表面负电荷物质的直接接触是必不可少的.由于穿膜肽的穿膜性质,其在分子生物学、药学、细胞生物学、疫苗学甚至影像学上有广泛的应用前景.本文对近年来穿膜肽的结构、穿膜机制和应用方面的研究进展进行了综述.     

穿膜肽提高纳米银穿膜活性的研究

目的合成纳米银,在其表面修饰穿膜肽(TAT),并检测修饰后纳米银粒对人乳腺癌耐阿霉素细胞(MCF-7/ADR)的穿膜活性。方法通过化学还原法制备纳米银(AgNP),并通过Ag-S共价键与TAT连接修饰AgNP。通过粒度仪、透射电镜、激光共聚焦显微镜、流式细胞仪以及二喹林甲酸法等仪器及方法对其表征、共价连接及TAT的介导活性进行测定。结果成功制备了10 nm以下的AgNP,且修饰TAT后的AgNP(AgNP-TAT)表现出了比AgNP更强的穿膜活性。结论 TAT修饰AgNP后能显著提高其穿膜活性。     

穿膜肽TAT和脑肿瘤靶向肽T7双修饰脂质体的制备和体外靶向性评价

本文旨在制备T7肽和穿膜肽TAT双修饰的脂质体(T7 and TAT dual modified liposomes,T7-TAT-LIP)用于血脑屏障和脑肿瘤细胞双级靶向药物递送。研究以CFPE为荧光探针,T7修饰的PEG-DSPE、TAT修饰的PEG-DSPE、卵磷脂、PEG-DSPE和胆固醇为材料,采用成膜水化法制备脂质体,对T7浓度、TAT浓度、连接T7和TAT的PEG长度进行优化,表征其粒径、zeta电位、形态和稳定性。以b End.3细胞和C6细胞为模型,考察T7-TAT-LIP的细胞摄取能力,表征其穿过血脑屏障和脑肿瘤细胞靶向能力。结果表明,T7用量为脂质的6%、修饰T7所用PEG链长为2000、TAT用量为脂质的0.5%、修饰TAT所用PEG链长为1000时所得到的双修饰脂质体被C6细胞摄取能力最强。优化后T7-TAT-LIP粒径为118 nm,zeta电位为-6.32 m V,透射电镜下形态圆整。脂质体在PBS中较为稳定,37℃放置24 h,浊度和粒径无明显变化;4~8℃放置1个月,粒径和PDI无明显变化。在不同时间点,b End.3和C6细胞摄取T7-TAT-LIP的强度均高于单配体修饰脂质体,且随着孵育时间提高,摄取浓度逐渐提高。这些结果说明,双修饰脂质体具有血脑屏障和脑肿瘤细胞双级靶向能力,且效果优于单配体修饰脂质体。     

新穿膜融合蛋白His-T1-绿色荧光蛋白的跨膜效率及其对细胞存活的影响

目的研究穿膜融合蛋白His-T1-绿色荧光蛋白(GFP)的跨膜效率及其对细胞存活的影响。方法以浓度为500mg·L-1的His-T1-GFP与人鼻咽癌CNE2或大鼠肾小管上皮NRK52E细胞孵育6h,应用荧光显微镜观察His-T1-GFP跨膜进入细胞的情况。应用多功能酶标仪检测细胞荧光强度,研究His-T1-GFP跨膜的动力学因素:以浓度为500mg·L-1的His-T1-GFP与CNE2或NRK52E细胞孵育10min至24h,观察孵育时间对穿膜作用的影响;以浓度为25mg·L-1至1.0g·L-1的His-T1-GFP与两种细胞孵育6h,观察蛋白浓度对跨膜效率的影响;以浓度为500mg·L-1的His-T1-GFP与两种细胞分别在4℃和37℃的条件下孵育6h,观察温度对蛋白跨膜效率的影响。用细胞乳酸脱氢酶(LDH)试剂盒和MTT法来评价5.0g·L-1浓度的His-T1-GFP对细胞存活的影响。结果在一定浓度范围内,His-T1-GFP能够有效穿透CNE2和NRK52E细胞膜,且对NRK52E细胞的跨膜效率明显高于His-TAT-GFP。His-T1-GFP在10min内就能有效跨膜进入细胞,并且在6h内进入细胞的量与时间成正相关。在一定浓度范围(25mg·L-1~1.0g·L-1)内,该蛋白进入细胞的量与自身浓度成正相关,而在4℃时该蛋白仍具有跨膜能力。当其终浓度高达5.0g·L-1时,对CNE2和NRK52E两种细胞几乎无毒性作用。结论His-T1-GFP蛋白是一种跨膜效率高且低毒的穿膜融合蛋白。     

细胞穿膜肽作为药物载体的研究进展

生物大分子在许多疾病的治疗中发挥着重要的作用, 但由于细胞膜的天然屏障作用, 只有分子质量小于600 Da的分子才能穿透细胞膜进入细胞内。这使得一些有治疗价值但无细胞膜穿透性的分子在细胞生物学、药学等领域的应用受到极大的限制。近年来发现的一些具有细胞穿透功能的短肽 (少于30个氨基酸) 即细胞穿膜肽 (CPPs), 能够有效地将蛋白质、多肽、核酸片段等以多种方式导入多种哺乳动物细胞, 其转导效率高且不会造成细胞损伤。CPPs的发现为生物大分子在细胞生物学、基因治疗、药物体内转运、临床药效评价以及细胞免疫学等研究领域等均具有良好的应用前景。本文就CPPs的种类特点、内化机制、应用及其存在的问题进行讨论和评述。     

肿瘤靶向细胞穿膜肽的设计合成及活性检测

目的合成一种可活化细胞穿膜肽(ACPPs)并初步探索其穿膜活性及亚细胞分布。方法 应用化学合成方法合成ACPPs,采用流式细胞仪检测ACPPs穿膜活性,免疫荧光法及全波长酶标仪检测表达ACPPs的肿瘤靶向性穿膜作用,用荧光显微镜观察ACPPs在细胞内的定位及ACPPs-pc-Ad.egfp复合物的亚细胞分布。结果 成功合成了ACPPs,ACPPs-异硫氰酸荧光素(FITC)组较牛血清清蛋白-FITC组荧光量大,差异有统计学意义(F=4 656.600,P=0.000),ACPPs具有肿瘤靶向性穿膜活性,人肺癌细胞A549、人结肠癌细胞SW480、人卵巢癌细胞OVCAR3细胞质内荧光量较人支气管上皮细胞HBE大,差异有统计学意义(F=37 947.676,P=0.000);ACPPs定位于细胞质并介导ACPPs-pc-Ad.egfp复合物分布于细胞质。结论 成功合成了ACPPs,ACPPs具有肿瘤靶向性穿膜活性并分布于细胞质。     

细胞穿膜肽在癌症治疗中的应用

细胞膜有选择渗透性,能阻止大多数外来因子进入细胞。然而许多治疗因子必须穿过细胞膜才能进入细胞内起作用。细胞穿膜肽是一组简短的阳离子序列,它具有很强的穿膜能力。自从1988年发现细胞穿膜肽后,细胞穿膜肽被用于携带各种物质,如小分子、核酸、抗体、纳米粒等进入细胞膜。本文重点介绍了近几年来关于细胞穿膜肽穿膜机制的研究进展,以及细胞穿膜肽作为运载体携带抗癌药物靶向进入肿瘤细胞,从而实现对肿瘤细胞的靶向性,同时可克服肿瘤的多药抗药性等研究进展。     

穿膜肽介导紫杉醇脂质体对肿瘤的治疗作用

目的制备和表征F3修饰紫杉醇脂质体,并进行细胞学和体内抗肿瘤评价。方法采用薄膜分散法制备脂质体,人肺腺癌细胞A549进行摄取评价;小鼠肝癌细胞H22荷瘤小鼠进行体内抗肿瘤活性评价。结果 F3修饰脂质体粒径为90 nm;该修饰后脂质体被细胞摄取能力明显增强,进而提高了药物的抗肿瘤活性,给药16天后,F3-Lipo组瘤体增长仅为11倍,相比于生理盐水组26倍,Taxol 18倍,未修饰脂质体14倍,有更好的抗肿瘤效果。结论 F3穿膜肽可以明显提高载体入胞能力,进而改善药物治疗作用。     

细胞穿膜肽在经皮给药系统中的应用研究概况

研发新型给药系统是提高药物疗效的重要途径,其中,经皮给药系统以其避免药物首过效应及胃肠灭活等独特的优势成为重要的创新方式之一,相关研究受到广泛关注,然而,一些药物特别是活性大分子物质难以透过皮肤屏障发挥药效,使临床应用受到限制。     

穿膜肽-抗体-微球偶联物的制备方法研究

目的：探讨制备穿膜肽-抗体-微球新型药物传送系统的可行性。方法：采用N-琥珀酰亚胺基-3-（2-吡啶二硫）-丙酸酯（SPDP）交联法将穿膜肽-增强型绿色荧光蛋白融合蛋白（CPPs-EGFP）、牛血清白蛋白微球（BSA-NS）、乙肝高效价免疫球蛋白（HBIg）分别采用一次偶联法和二次偶联法两种交联方案进行共价交联,采用还原和非还原SDS聚丙烯酰胺凝胶电泳（SDS-PAGE）和免疫荧光法评价穿膜肽、抗体、微球间的交联。结果：两种交联方案制备的穿膜肽-抗体-微球偶联物,SDS-PAGE还原电泳均可见在低分子量端形成三条蛋白条带,非还原电泳均未见条带;在不同激发波长的荧光显微镜下,均可见微球表面分别发出绿色荧光和红色荧光。结论：应用SP-DP交联剂,无论是一次偶联法还是二次偶联法均能够将穿膜肽、抗体、微球有效地进行偶联,为进一步研究穿膜肽-抗体-微球新型药物传送系统的特性奠定了基础。     

Modification Strategy of D-leucine Residue Addition on a Novel Peptide from Odorrana schmackeri,with Enhanced Bioactivity and In Vivo Efficacy

Brevinins are a well-characterised, frog-skin-derived, antimicrobial peptide (AMP) family, but their applications are limited by high cytotoxicity. In this study, a wild-type des-Leu2 brevinin peptide, named brevinin-1OS (B1OS), was identified from Odorrana schmackeri. To explore the significant role of the leucine residue at the second position, two variants, B1OS-L and B1OS-D-L, were designed by adding L-leucine and D-leucine residues at this site, respectively. The antibacterial and anticancer activities of B1OS-L and B1OS-D-L were around ten times stronger than the parent peptide. The activity of B1OS against the growth of Gram-positive bacteria was markedly enhanced after modification. Moreover, the leucine-modified products exerted in vivo therapeutic potential in an methicillin-resistant Staphylococcus aureus (MRSA)-infected waxworm model. Notably, the single substitution of D-leucine significantly increased the killing speed on lung cancer cells, where no viable H838 cells survived after 2 h of treatment with B1OS-D-L at 10 μM with low cytotoxicity on normal cells. Overall, our study suggested that the conserved leucine residue at the second position from the N-terminus is vital for optimising the dual antibacterial and anticancer activities of B1OS and proposed B1OS-D-L as an appealing therapeutic candidate for development.     

鹿角脱盘多肽的分离纯化及其降糖活性的研究

以鹿角脱盘为原材料,经稀醋酸提取,再利用Resource S、Superdex 75、反相HPLC进一步纯化和质谱检测确定其Mr为7 127.6的多肽,命名为鹿角脱盘多肽,对其进行了理化分析。通过对KK-ay小鼠单次给药观察粗品的降糖效果,并采用高胰岛素诱发HepG2细胞建立胰岛素抵抗模型,初步研究了鹿角脱盘多肽对胰岛素抵抗HepG2细胞葡萄糖消耗的影响。结果表明鹿角脱盘多肽具有明显的降糖活性,不仅能够降低KK-ay小鼠的血糖水平,并且200、100μg/mL粗品和100μg/mL鹿角脱盘多肽均能显著促进胰岛素抵抗HepG2细胞模型的葡萄糖消耗。     

Lanthanum Element Induced Imbalance of Mineral Nutrients, HSP 70 Production and DNA-Protein Crosslink, Leading to Hormetic Response of Cell Cycle Progression in Root Tips of Vicia faba L. seedlings

The effects and mechanisms of rare earth elements on plant growth have not been extensively characterized. In the current study, Vicia faba L. seedlings were cultivated in lanthanum (La)-containing solutions for 10 days to investigate the possible effects and mechanisms of La on cell proliferation and root lengthening in roots. The results showed that increasing La levels resulted in abnormal calcium (Ca), Ferrum (Fe) or Potassium (K) contents in the roots. Flow cytometry analysis revealed G1/S and S/G2 arrests in response to La treatments in the root tips. Heat shock protein 70 (HSP 70) production showed a U-shaped dose response to increasing La levels. Consistent with its role in cell cycle regulation, HSP 70 fluctuated in parallel with the S-phase ratios and proliferation index. Furthermore, DNA-protein crosslinks (DPCs) enhanced at higher La concentrations, perhaps involved in blocking cell progression. Taken together, these data provide important insights into the hormetic effects and mechanisms of REE(s) on plant cell proliferation and growth.     

流式细胞检测高压CO2对胃癌MMP2和MMP9水平的影响

目的:探讨高压二氧化碳(CO2)对胃癌细胞腹腔侵袭转移能力的影响.方法:体外培养高侵袭力人胃癌MKN45细胞株,在高压CO2(25 mmHg)及不同持续时间(1、2、3 h)干预后,应用流式细胞技术,检测其MMP2和MMP9的表达水平变化.结果:高压CO2作用后胃癌MKN45细胞株MMP2和MMP9蛋白表达有所变化.与常规细胞培养比较,MMP2和MMP9表达差异较为明显(P＜0.001,P＜0.01).结论:CO2对胃癌细胞的侵袭能力会产生一定的影响,高压CO2环境对胃癌细胞的侵袭能力影响较大.     

MRI visualization of neuroinflammation using VCAM-1 targeted paramagnetic micelles

The detection of neuroinflammatory processes using innovative and non-invasive imaging techniques is of great help to deeply investigate the onset and progression of neurodegenerative diseases. Since Vascular Cell Adhesion Molecule (VCAM-1) is over expressed at the blood brain barrier in the event of neuroinflammation, the goal of this work was the testing of MRI detectable micelles targeted towards VCAM-1 to visualize inflamed regions in a mouse model of acute neuroinflammation. The developed probe allowed for the early detection of the disease, with higher T₁ signal enhancement and more precise localization in comparison to untargeted micelles or to the clinically approved contrast agent MultiHance. Moreover, the relatively long blood half-life of the nanosystem (ca. 6.3 h) guaranteed a good accumulation in the inflamed regions, paving the way to future diagnostic/theranostic applications, implying the loading of neuroprotective or even anti-cancer drugs inside the core of the micelles.     

Oral delivery of proteins and peptides: Challenges,status quo and future perspectives

Proteins and peptides (PPs) have gradually become more attractive therapeutic molecules than small molecular drugs due to their high selectivity and efficacy, but fewer side effects. Owing to the poor stability and limited permeability through gastrointestinal (GI) tract and epithelia, the therapeutic PPs are usually administered by parenteral route. Given the big demand for oral administration in clinical use, a variety of researches focused on developing new technologies to overcome GI barriers of PPs, such as enteric coating, enzyme inhibitors, permeation enhancers, nanoparticles, as well as intestinal microdevices. Some new technologies have been developed under clinical trials and even on the market. This review summarizes the history, the physiological barriers and the overcoming approaches, current clinical and preclinical technologies, and future prospects of oral delivery of PPs.     

PROTAC technology: A new drug design for chemical biology with many challenges in drug discovery

Target Protein Degradation TPD is a new avenue and revolutionary for therapeutics because redefining the principles of classical drug discovery and guided by event-based target activity rather than the occupancy-driven activity. Since the discovery of the first PROTAC in 2001, TPD represents a rapidly growing technology, with applications in both drug discovery and chemical biology. Over the last decade, many questions have been raised and today the knowledge gained by each team has elucidated a number of them, although there is still a long way to go. The objective of this work is to present the challenges that the PROTAC strategy has very recently addressed in drug design and discovery by presenting extremely recent results from the literature and to provide guidelines in the drug design of new PROTACs as successful therapeutic modality for medicinal chemists.