Setoguchi Y, Noto K, Iwakami S, Tajima M, Kira S
Department of Respiratory Medicine, Juntendo University School of Medicine, Tokyo, Japan.
Nihon Kyobu Shikkan Gakkai Zasshi. 1994 Dec;32 Suppl:86-95.
Advances in recombinant DNA technology and molecular and cellular biology have made it feasible to introduce genes into living cells. The most sophisticated gene transduction methods have bee applied to gene therapy strategies for the potential treatment of genetic diseases. In regard to lung diseases, alpha 1-antitrypsin deficiency and cystic fibrosis, the most common hereditary lung disorders in Caucasians, have been targeted for gene therapy. To date, gene therapy studies have been confined to ex vivo strategies for treatment of ADA deficiency with retroviral vectors. However, there are two major obstacles to gene transfer to the bronchial epithelium. First, bronchial epithelium, such as that with ciliated cells, is terminally differentiated, and does not divide rapidly. Second, the complex architecture of the lung precludes replacing the existing bronchial epithelium with cells modified by gene transfer. In the context of these properties of bronchial epithelium, adenovirus vectors have been evaluated for direct introduction of therapeutic genes to bronchial epithelium via the airway in vivo. An in vivo experiment revealed that gene transfer with a replication-deficient adenovirus containing the E. coli lacZ (beta-galactosidase) gene driven by cytomegalovirus promoter (AdCMVlacZ) was 10(4) times more efficient than gene transfer with a plasmid containing the same expression cassette (pCMVlacZ). An experiment based on in vitro data was done to evaluate the distribution of the expression of the exogenous genes transferred by adenovirus vectors. Intratracheal administration of AdCMVlacZ into lungs of experimental animals resulted in a high number of beta-gal-positive epithelial cells in bronchiols, rather than in proximal bronchi. Thus, a replication-deficient adenovirus can be used to transfer exogenous genes to airway epithelial cells in vivo. This technique may be useful in gene therapy for cystic fibrosis. Gene transfer can be thought of as the use of genetic information to modity the milieu of the target organ. In addition, gene transfer may allow the introduction of new genes, or the alteration tion of existing genes in intact animals. Gene transfer could them be used to produce animal models of human lung diseases that are particularly difficult to study.
重组DNA技术以及分子与细胞生物学的进展使得将基因导入活细胞成为可能。最先进的基因转导方法已被应用于基因治疗策略，以潜在治疗遗传疾病。就肺部疾病而言，α1-抗胰蛋白酶缺乏症和囊性纤维化这两种白种人中最常见的遗传性肺部疾病已成为基因治疗的目标。迄今为止，基因治疗研究仅限于用逆转录病毒载体对腺苷脱氨酶缺乏症进行体外治疗策略。然而，将基因转移至支气管上皮存在两个主要障碍。首先，支气管上皮，如带有纤毛细胞的上皮，是终末分化的，且不会快速分裂。其次，肺的复杂结构使得无法用通过基因转移修饰的细胞替代现有的支气管上皮。鉴于支气管上皮的这些特性，已对腺病毒载体进行评估，以通过气道在体内将治疗性基因直接导入支气管上皮。一项体内实验表明，用含有由巨细胞病毒启动子驱动的大肠杆菌lacZ（β-半乳糖苷酶）基因的复制缺陷型腺病毒（AdCMVlacZ）进行基因转移比用含有相同表达盒的质粒（pCMVlacZ）进行基因转移效率高10^4倍。基于体外数据进行了一项实验，以评估腺病毒载体转移的外源基因的表达分布。将AdCMVlacZ经气管内给药至实验动物肺部后，细支气管中而非近端支气管中有大量β-半乳糖苷酶阳性上皮细胞。因此，复制缺陷型腺病毒可用于在体内将外源基因转移至气道上皮细胞。该技术可能对囊性纤维化的基因治疗有用。基因转移可被视为利用遗传信息来改变靶器官的环境。此外，基因转移可能允许在完整动物中引入新基因或改变现有基因。基因转移进而可用于建立特别难以研究的人类肺部疾病的动物模型。
