图片来源:medicalxpress.com
2016年2月2日 讯 /生物谷BIOON/ –1999年,美国青少年杰西-基辛格(Jesse Gelsinger)死于转录基因载体而引起的强烈免疫反应,患者在临床试验后接受基因疗法后四天出现严重的炎性综合症反应。近日,刊登在国际著名杂志Nature上的一项研究论文中,来自斯坦福大学的病毒学家Jan Carette就表示基因疗法领域或许可以再次被提上日程,当前治疗许多遗传性障碍的基因疗法都在欧洲得到了批准,而且在美国对抗先天性失明的基因疗法也已经接近批准的阶段。
很多科学家关注此项领域不足为奇,而且越来越多的方法也都将遗传物质直接引入人类细胞,这其中就包括了利用驯化的病毒来引入人类细胞治疗相关的疾病;如果有一种病毒非常善于此项任务,即适合感染细胞,那么病毒或许就会使用它们的伎俩将基病毒自身的基因转移到细胞的DNA中,从而拦截细胞的复制机器,使得细胞产生众多病毒的拷贝。
科学家们如今越来越会驯服病毒从事相关的研究了,病毒在研究者的巧妙调控下拥有了感染细胞插入基因的特殊本领,但病毒本身却并不会含有破坏组织、干扰机体免疫系统的作用了。腺病毒相关病毒在人体中到处存在但却不引发任何相关的疾病,因此其或许就是科学家们下手的对象,研究者表示,一旦对腺病毒相关病毒进行合适的生物工程化操作,期就会在随意复制引发机体免疫反应的情况下感染任何种类的细胞,相反病毒会将治疗疾病的相关基因运输到感染的细胞中从而修复病人机体缺失的代谢、酶类及合成性途径。
为了阐明如何有效“驯服”病毒来有效侵袭细胞,从而扩大基因疗法的有效性及吸引力,研究者在文章中进行了一系列实验;研究者表示,病毒可以通过将特殊分子嵌合到细胞表面来靶向作用细胞,以腺病毒相关病毒为例,病毒的受体分子是已知的,而且这种分子具有一定的用处,其并不会阻断入侵病毒利用病毒和细胞间的互引力;为了进入到细胞核的位点,病毒就不得不更好地对细胞进行渗透。
本文研究中,研究人员Carette及其同事在人类细胞中鉴别出了从事运输任务的特殊分子,该研究发现或为提高或降低不同组织中分子的表达,从而为治疗性基因成功运输到目的位点从事治疗作用提供了新的线索和希望。(基因宝jiyinbao.com)
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An essential receptor for adeno-associated virus infection
S. Pillay, N. L. Meyer, A. S. Puschnik, O. Davulcu, J. Diep, Y. Ishikawa, L. T. Jae, J. E. Wosen, C. M. Nagamine, M. S. Chapman & J. E. Carette
Adeno-associated virus (AAV) vectors are currently the leading candidates for virus-based gene therapies because of their broad tissue tropism, non-pathogenic nature and low immunogenicity1. They have been successfully used in clinical trials to treat hereditary diseases such as haemophilia B (ref. 2), and have been approved for treatment of lipoprotein lipase deficiency in Europe3. Considerable efforts have been made to engineer AAV variants with novel and biomedically valuable cell tropisms to allow efficacious systemic administration1, 4, yet basic aspects of AAV cellular entry are still poorly understood. In particular, the protein receptor(s) required for AAV entry after cell attachment remains unknown. Here we use an unbiased genetic screen to identify proteins essential for AAV serotype 2 (AAV2) infection in a haploid human cell line. The most significantly enriched gene of the screen encodes a previously uncharacterized type I transmembrane protein, KIAA0319L (denoted hereafter as AAV receptor (AAVR)). We characterize AAVR as a protein capable of rapid endocytosis from the plasma membrane and trafficking to the trans-Golgi network. We show that AAVR directly binds to AAV2 particles, and that anti-AAVR antibodies efficiently block AAV2 infection. Moreover, genetic ablation of AAVR renders a wide range of mammalian cell types highly resistant to AAV2 infection. Notably, AAVR serves as a critical host factor for all tested AAV serotypes. The importance of AAVR for in vivo gene delivery is further highlighted by the robust resistance of Aavr−/− (also known as Au040320−/− and Kiaa0319l−/−) mice to AAV infection. Collectively, our data indicate that AAVR is a universal receptor involved in AAV infection.