干扰素诱导的跨膜蛋白在肿瘤中的研究进展

干扰素诱导的跨膜蛋白(IFITM)是一种近来发现的细胞内抗病毒蛋白家族,它能抑制多种有或者无胞膜病毒的复制而起到抗病毒作用;同时近期有研究显示IFITM3对人类多种肿瘤细胞及干细胞的迁移等起重要作用,但IFITM3在人类肿瘤发生、发展和扩散转移的作用机制尚不明确.本文主要对IFITM3蛋白在人类肿瘤的研究进展及未来的研究方向作一综述.     

诱导表达人IFITM3的293细胞株的建立及其对H1N1型流感病毒侵染作用

目的建立诱导表达IFITM3蛋白的293细胞株,为进一步研究人IFITM3对H1N1型流感病毒侵染的作用及其分子机制提供细胞模型。 方法构建IFITM3/pcDNA5/FRT/TO expression vector质粒及诱导表达细胞株,建立HN1型流感病毒假病毒评价系统,利用蛋白印迹（Western blot）和荧光素酶报告基因对筛选的诱导表达细胞株功能进行检测。 结果建立的293诱导表达细胞株能够很好表达目的蛋白,且诱导表达出来的IFITM3蛋白使H1N1型流感假病毒感染率下降97%（t = 38.08、P < 0.001）,使水泡性口炎假病毒（VSVpp）感染率下降68%（t = 54.56、P < 0.001）,而阴性对照组小鼠白血病假病毒（MLVpp）感染率（t = 1.282、P = 0.2208）和拉沙假病毒（LASVpp）感染率（t = 0.4814、P = 0.6377）无显著影响。 结论IFITM3蛋白诱导表达细胞株可以显著抑制H1N1型流感病毒感染,为进一步深入研究IFITM3抑制流感病毒感染的作用机制和分子机理提供了细胞模型和实验基础。     

丙型肝炎病毒融合蛋白及融合机制

丙型肝炎病毒（hepatitis C virus,HCV）属于黄病毒科、肝病毒属,是有包膜的单正链RNA病毒,其包膜糖蛋白E1、E2均位于病毒颗粒外表面,主要参与子代病毒颗粒的形成（如组装）及病毒新一轮感染（如细胞黏附、受体结合以及膜融合等过程）。目前研究认为,有包膜病毒均通过一个共同机制--膜融合将自身基因组输送至靶细胞,然后进行复制、转录与翻译、子代病毒组装与释放。经受体结合[如Ⅰ型人免疫缺陷病毒（human immunodeficiency virus,HIV-1）]、pH改变[如流感病毒、登革病毒（dengue virus,DENV）和塞姆利基森林病毒（Semliki forest virus,SFV）]或二者兼具（如鸟类肉瘤病毒、白血病病毒）的方式,与细胞膜或内体（endosome）膜发生融合[1]。本文将对近年来HCV E1、E2所介导的膜融合研究作一综述。     

IFITM3在原发性肝癌中的表达及其对MMP-9调控效应

目的:探讨干扰素诱导跨膜蛋白3(IFITM3)在原发性肝癌中的表达及作用。方法:用免疫组化与Western blot检测60例肝癌组织及对应癌旁组织中IFITM3以及基质金属蛋白酶9(MMP-9)蛋白的表达;构建IFITM3小干扰RNA片段(psilencer3.1-sh IFITM3)转染肝癌Hep G2细胞,用实时荧光定量PCR及Western blot法、CCK8法、Transwell试验和划痕试验分别检测细胞转染后IFITM3和MMP-9 m RNA及蛋白表达、增殖能力以及侵袭与迁移能力的变化。结果:与癌旁组织比较,肝癌组织中IFITM3与MMP-9的蛋白的阳性表达率与表达量均明显升高(81.67%vs.13.33%;88.33%vs.8.33%,均P0.05);psilencer3.1-sh IFITM3转染后,Hep G2细胞IFITM3和MMP-9的m RNA与蛋白表达水平、细胞增值率均明显降低,穿膜细胞数明显减少,划痕融合速率明显减慢。以上定量指标间的差异均有统计学意义(均P0.05)。结论:原发性肝癌中IFITM3表达增高,高表达的IFITM3可能通过调控MMP-9的表达而促进肝癌细胞的增殖、侵袭和迁移。     

Tat-Vp3融合蛋白在杆状病毒-昆虫细胞表达系统中的表达与纯化及其促凋亡功能的研究

目的：采用杆状病毒-昆虫细胞表达系统获取可溶性 His-Tat-Vp3融合蛋白,并观察其对细胞增殖和凋亡的影响。方法：构建重组质粒 pFastBacTM1-TAT-VP3,转化DH10Bac 感受态细胞,获得杆状病毒质粒,转染 Sf9昆虫细胞,得到重组杆状病毒,纯化并扩增该病毒。用最适滴度的病毒刺激 Sf9细胞以诱导 His-Tat-Vp3蛋白表达,经 SDS-PAGE和 Western bolt鉴定,获得分子质量约21 kDa 的融合蛋白。采用 MTT 实验与流式细胞技术检测500、1000、2000 nmol/L的融合蛋白抑制肿瘤细胞（HeLa细胞）增殖及促凋亡的活性。结果：通过昆虫表达系统成功表达及纯化出Tat-Vp3融合蛋白,其中1000、2000 nmol/L融合蛋白组可显著抑制肿瘤细胞的增殖,并提高细胞的凋亡率。结论：成功构建 His-TAT-VP3融合蛋白昆虫系统表达载体,在昆虫表达系统中可诱导性可溶性高表达,所获融合蛋白能显著抑制 H eLa细胞的增殖,并促进其凋亡。     

CNP2线粒体定位信号以及磷酸酯酶活性对抑制HIV-1 Gag蛋白组装作用的影响

目的研究CNP2在线粒体上的定位以及磷酸酯酶活性是否参与抑制HIV-1病毒颗粒组装。 方法采用RT-PCR扩增野生型CNP2编码区,插入到真核表达载体pcDNA5,构建融合蛋白Flag-CNP2的表达质粒pcDNA5-Flag-CNP2。应用融合PCR诱导突变法构建CNP1及CNP2突变表达载体。CNP表达载体分别与HIV-1假病毒包装质粒pLP1、pLP2、pLP/VSVG、pLenti6-EGFP共同瞬时转染293T细胞。集落形成实验检测上清病毒滴度,Western blot检测细胞中Gag蛋白p55、p24以及细胞培养上清中p24的表达情况。 结果与对照组比较,CNP2、CNP1、CNP2-S9/22A可以显著抑制细胞中病毒的释放,培养上清中病毒滴度显著降低（滴度分别为5.66、4.20、5.75、6.63 Log₁₀IU/ml,NC组为7.65 Log₁₀ IU/ml;t = 58.23、17.24、12.77、6.131,P = 0.0035、0.0066、0.0004、0.0039）。CNP1抑制HIV-1病毒颗粒组装作用更强,Western blot检测培养上清中病毒蛋白完全p24消失。磷酸酯酶结构域（2HM）突变后CNP2抑制HIV-1病毒颗粒组装的作用显著降低。 结论CNP2抑制HIV-1病毒颗粒组装需要磷酸酯酶结构域（2HM）的参与,CNP2的线粒体定位信号可能会影响其抑制HIV病毒颗粒组装的作用。     

microRNA-21通过上皮间质转化促进胆管癌细胞侵袭转移的研究

目的探讨microRNA-21（miR-21）对胆管癌RBE细胞侵袭转移能力的影响及其内在机制。 方法miR-21及其抑制基因片段（miR-21i）通过慢病毒载体感染胆管癌RBE细胞,RT-PCR用于检测RBE细胞中miR-21表达;Transwell体外侵袭实验和细胞划痕试验用于检测RBE细胞侵袭及转移能力;Western blotting用于检测PTEN蛋白和上皮间质转化（EMT）特征性蛋白E-cadherin、N-cadherin、Vimentin表达情况。 结果miR-21过表达促进RBE细胞侵袭和转移,miR-21低表达抑制RBE细胞的侵袭和转移。miR-21过表达能够降低PTEN蛋白和E-cadherin蛋白,增强N-cadherin和Vimentin蛋白的表达;转染miR-21i抑制基因组（miR-21i）组则有相反的效果,而转染空白基因组（对照组）相应蛋白表达无明显变化。 结论miR-21起到癌基因的作用,可增强胆管癌细胞侵袭和转移能力,其机制是通过调节抑癌基因PTEN及改变EMT相关蛋白的变化。这些发现为胆管癌侵袭转移的分子机制提供新的科学依据。     

乙型肝炎病毒核苷（酸）类似物耐药研究进展

核苷（酸）类似物耐药问题是慢性乙型肝炎抗病毒治疗中的重要问题之一。随着核苷（酸）类似物耐药研究的不断进展,耐药检测新技术逐渐被研发,对病毒变异的机制了解更加精确且全面。核苷（酸）类似物新的可疑耐药位点不断被提出,但这些位点的临床意义尚待进一步明确。尤其是慢性乙型肝炎患者应用核苷（酸）类似物抗病毒治疗的过程即是病毒与机体相互作用的过程逐渐被认知,在此过程中病毒准种及全基因组序列存在动态演变。核苷（酸）类似物耐药仅为此相互作用过程的表现之一,应将核苷（酸）类似物耐药放在机体免疫与病毒相互作用的整体背景下进行研究。     

干扰素诱导跨膜蛋白3在肝癌中的表达及功能研究

目的:探讨干扰素诱导跨膜蛋白3(IFITM3)在原发性肝癌中的表达及意义。方法:收集55例配对的肝癌与癌旁组织标本,分别用免疫组化和Western blot检测组织标本中IFITM3蛋白的表达,并分析IFITM3表达与肝癌患者临床病理因素的关系;用IFITM3干扰片段转染在肝癌Hep G2细胞后,观察肝癌细胞侵袭迁移能力的变化。结果:免疫组化结果显示,IFITM3蛋白在肝癌组织中的阳性表达率明显高于癌旁组织(88.2%vs.23.5%,P0.05),低/中分化的肝癌组织中阳性表达率高于高分化的肝癌组织(80.0%vs.8.3%,P0.05);Western blot结果显示,肝癌组织中IFITM3蛋白表达量明显高于癌旁组织(1.2 399 vs.0.9 565,P0.05);IFITM3表达量与门静脉癌栓形成、肿瘤大小、TNM分期有关(均P0.05)。Hep G2细胞转染IFITM3干扰片段后,侵袭、迁移能力均明显减弱。结论:IFITM3在肝癌中表达升高,且其升高程度与肝癌细胞的侵袭、迁移能力密切相关,提示IFITM3在肝癌的恶性进展中起了重要作用。     

hTERT启动子调控的CXCR4-shRNA逆转录病毒抑制膀胱癌细胞侵袭、增殖的体外研究

目的构建人端粒酶逆转录酶（hTERT）启动子调控的趋化因子受体4（CXCR4）的短发夹RNA（shRNA）逆转录病毒表达载体,并研究其对hTERT阳性膀胱癌细胞中CXCR4表达的抑制效应及对细胞侵袭、增殖的影响。方法用PCR扩增特异CXCR4-shRNA的DNA片段,以hTERT启动子代替U6启动子,将重组基因片段导入到逆转录病毒载体,收获病毒后分别感染膀胱癌细胞BIU87及人胚肺成纤维细胞MRC5和人乳腺癌细胞MCF7,RT-PCR、Western blot检测CXCR4 mRNA及蛋白的表达。MTT法检测细胞增殖变化。Transwell小室实验检测细胞体外侵袭能力的变化。结果hTERTpro—CXCR4-shRNA能显著抑制MCF7、BIU87细胞CXCR4 mRNA及蛋白的表达,48h mRNA抑制率分别为（87．09±7．60）％、（91．02±11．32）％,48h蛋白抑制率分别为（89.01±4．87）％、（90．42±9．64）％,其对MRC5细胞不抑制。感染重组病毒的膀胱癌细胞体外侵袭、增殖能力均显著下降。结论重组病毒中hTERT启动子调控的下游RNA干扰序列可靶向表达于hTERT阳性膀胱癌细胞、乳腺癌细胞,不表达于hTERT阴性MRC5细胞。     

Characterization of the osteoblast-specific transmembrane protein IFITM5 and analysis of IFITM5-deficient mice

Interferon-inducible transmembrane protein 5 (IFITM5) is an osteoblast-specific membrane protein whose expression peaks around the early mineralization stage during the osteoblast maturation process. To investigate IFITM5 function, we first sought to identify which proteins interact with IFITM5. Liquid chromatography mass spectrometry revealed that FK506-binding protein 11 (FKBP11) co-immunoprecipitated with IFITM5. FKBP11 is the only protein it was found to interact with in osteoblasts, while IFITM5 interacts with several proteins in fibroblasts. FKBPs are involved in protein folding and immunosuppressant binding, but we could not be sure that IFITM5 participated in these activities when bound to FKBP11. Thus, we generated Ifitm5-deficient mice and analyzed their skeletal phenotypes. The skeletons, especially the long bones, of homozygous mutants (Ifitm5 ^−/−) were smaller than those of heterozygous mutants (Ifitm5 ^+/−), although we did not observe any significant differences in bone morphometric parameters. The effect of Ifitm5 deficiency on bone formation was more significant in newborns than in young and adult mice, suggesting that Ifitm5 deficiency might have a greater effect on prenatal bone development. Overall, the effect of Ifitm5 deficiency on bone formation was less than we expected. We hypothesize that this may have resulted from a compensatory mechanism in Ifitm5-deficient mice.     

IFITM5 mutations and osteogenesis imperfecta

Interferon-induced transmembrane protein 5 (IFITM5) is an osteoblast-specific membrane protein that has been shown to be a positive regulatory factor for mineralization in vitro. However, Ifitm5 knockout mice do not exhibit serious bone abnormalities, and thus the function of IFITM5 in vivo remains unclear. Recently, a single point mutation (c.-14C>T) in the 5′ untranslated region of IFITM5 was identified in patients with osteogenesis imperfecta type V (OI-V). Furthermore, a single point mutation (c.119C>T) in the coding region of IFITM5 was identified in OI patients with more severe symptoms than patients with OI-V. Although IFITM5 is not directly involved in the formation of bone in vivo, the reason why IFITM5 mutations cause OI remains a major mystery. In this review, the current state of knowledge of OI pathological mechanisms due to IFITM5 mutations will be reviewed.     

Localization of SNAREs, NSF and Caveolin 1 in human spermatozoa: relationship with seminal parameters

Membrane fusion is a very important process in gametes. The mechanism of membrane fusion during the AR has been proposed to involve SNAREs. Our aim is to quantify patterns of localization of Caveolin 1, SNAREs (Syntaxin 1A, Syntaxin 2 and VAMP 1) and NSF on human sperm, to determine how the differential distribution of these proteins might be interdependent and to evaluate if this distribution is related with seminal parameters. These proteins are present in different regions of the head of human sperm: anterior, equatorial and posterior regions and that Syntaxin 2 and Syntaxin 1A had a slightly different pattern of labelling. The presence and localization of SNAREs, NSF and Caveolin 1 do not correlate with seminal parameters. There is significant correlation between NSF and SNAREs, which may indicate a cooperation of these proteins in membrane fusion mechanisms of human sperm.     

Effects of pegylated interferon α-2a on hepatitis-C-virus-associated glomerulonephritis

Hepatitis C virus (HCV) infection leads to chronic liver disease, but it has also been associated with extrahepatic manifestations. Membranoproliferative glomerulonephritis (MPGN) is the most common renal disease associated with HCV. Although renal disease related to HCV in adults has been well studied, it has not been well studied in children because it is rare. A recent study found that antiviral therapy was effective for adult patients with HCV-associated MPGN. We report a 9-year-old girl with HCV-associated MPGN. Her HCV genotype was 1b, and her virus load was high. The first renal biopsy showed mesangial proliferation and partial double contours of the basement membrane on light microscopy and immunofluorescence staining with immunoglobulin (Ig) M, IgG, and C3. The patient was successfully treated with pegylated interferon (IFN) α-2a monotherapy. The antiviral therapy was generally well tolerated. After antiviral therapy, a sustained virological response—defined as negative HCV ribonucleic acid (RNA) at least 24 weeks after antiviral treatment—was achieved, the proteinuria disappeared, and the second renal biopsy showed improvement.     

IFITM1在胰腺癌中的表达及对胰腺癌细胞生物学行为的影响

背景与目的:干扰素诱导的跨膜蛋白1(IFITM1)是一种在淋巴细胞中转导同型黏附信号的膜复合物,在胰腺癌组织中表达量异常,但是其在胰腺癌中的作用机制则仍不清楚,因此,本研究初步探讨IFITM1的表达对胰腺癌细胞生物学行为的影响.方法:用Western blot法检测78例胰腺癌患者(32例转移,46例未转移)的癌组织和...     

Osteogenesis imperfecta without features of type V caused by a mutation in the IFITM5 gene

Osteogenesis imperfecta (OI) is typically caused by mutations in type 1 collagen genes, but in recent years new recessive and dominant forms caused by mutations in a plethora of different genes have been characterized. OI type V is a dominant form caused by the recurrent (c.‐14C > T) mutation in the 5'UTR of the IFITM5 gene. The mutation adds five residues to the N‐terminus of the IFITM5, but the pathophysiology of the disease remains to be elucidated. Typical clinical features present in the majority of OI type V patients include interosseous membrane calcification between the radius and ulna and between the tibia and fibula, radial head dislocation, and significant hyperplastic callus formation at the site of fractures. We report a 5‐year‐old child with clinical features of OI type III or severe OI type IV (characteristic facies, gray sclerae, typical fractures) and absence of classical features of OI type V with a de novo recurrent IFITM5 mutation (c.‐14C > T), now typical of OI type V. This highlights the variability of OI caused by IFITM5 mutations and suggests screening for mutations in this gene in most cases of OI where type 1 collagen mutations are absent. © 2013 American Society for Bone and Mineral Research.     

Clearance of Hepatitis C Virus Prior to Lung Transplantation: A Case Report

Hepatitis C virus (HCV) continues to be considered a relative contraindication to lung transplantation due to concerns of progression of liver disease with the introduction of immunosuppression. Since the recent introduction of effective antiviral therapy for HCV, new approaches in the management of the HCV-positive recipient are being utilized in liver transplantation to clear HCV pre- and post-transplant. Herein, we report use of ledipasvir/sofosbuvir for HCV clearance prior to lung transplantation in a patient with usual interstitial pneumonia. Listing for transplant was delayed until completion of HCV treatment, and he subsequently required extracorporeal membrane oxygenation as a bridge to transplantation due to progressive hypoxia. With antiviral cure rates exceeding 90%, HCV should no longer be considered a relative contraindication to lung transplant, and timing of antiviral treatment should consider the progressive nature of the recipient's lung disease.