Gene therapy is being investigated for a range of serious lung diseases, such as cystic fibrosis and emphysema. Recombinant adeno-associated virus (rAAV) is a well-established, safe, viral vector for gene delivery with multiple naturally occurring and artificial serotypes available displaying alternate cell, tissue, and species-specific tropisms. Efficient AAV serotypes for the transduction of the conducting airways have been identified for several species; however, efficient serotypes for human lung parenchyma have not yet been identified. Here, we screened the ability of multiple AAV serotypes to transduce lung bud organoids (LBOs)—a model of human lung parenchyma generated from human embryonic stem cells. Microinjection of LBOs allowed us to model transduction from the luminal surface, similar to dosing via vector inhalation. We identified the naturally occurring rAAV2 and rAAV6 serotypes, along with synthetic rAAV6 variants, as having tropism for the human lung parenchyma. Positive staining of LBOs for surfactant proteins B and C confirmed distal lung identity and suggested the suitability of these vectors for the transduction of alveolar type II cells. Our findings establish LBOs as a new model for pulmonary gene therapy and stress the relevance of LBOs as a viral infection model of the lung parenchyma as relevant in SARS-CoV-2 research.

中文翻译：

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在人胚胎干细胞衍生的肺类器官中鉴定用于肺基因治疗的 AAV 血清型

正在研究针对一系列严重肺部疾病的基因疗法，例如囊性纤维化和肺气肿。重组腺相关病毒 (rAAV) 是一种成熟、安全的病毒载体，用于基因传递，具有多种可用的天然和人工血清型，可显示替代细胞、组织和物种特异性的趋向性。已经为几种物种鉴定了用于传导气道转导的有效 AAV 血清型；然而，人类肺实质的有效血清型尚未确定。在这里，我们筛选了多种 AAV 血清型转导肺芽类器官 (LBO)——一种由人类胚胎干细胞产生的人类肺实质模型的能力。LBO 的显微注射使我们能够模拟来自管腔表面的转导，类似于通过矢量吸入给药。我们确定了天然存在的 rAAV2 和 rAAV6 血清型，以及合成的 rAAV6 变体，它们对人肺实质具有趋向性。LBOs 表面活性蛋白 B 和 C 的阳性染色证实了远端肺的身份，并表明这些载体适用于转导 II 型肺泡细胞。我们的研究结果将 LBO 确立为肺基因治疗的新模型，并强调 LBO 作为肺实质病毒感染模型的相关性与 SARS-CoV-2 研究相关。