Laboratory of Biochemistry and Molecular Biology, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6, Yamadaoka, Suita, Osaka, 565-0871, Japan.
J Control Release. 2011 Sep 25;154(3):285-9. doi: 10.1016/j.jconrel.2011.06.020. Epub 2011 Jun 16.
A major limitation of the use of adenovirus (Ad) vectors is the innate immune response, which causes inflammatory cytokine production and tissue damages. To overcome this limitation, it is necessary to develop safer Ad vectors that are less likely to induce innate immunity. The Ad genome encodes two non-coding small RNAs, virus-associated (VA)-RNA I and VA-RNA II, which are transcribed by RNA polymerase III and promote Ad replication. Recently, we reported that VA-RNAs are produced in the cells transduced with a conventional first-generation (E1-deleted) Ad vector (FG-Ad) and trigger innate immune responses through intracellular nucleic acid sensors. In the present study, we have developed a VA-RNA-deleted Ad (AdΔVR) vector, in which the transcriptional control elements of the VA-RNA-expression were deleted. Although conventional HEK293 cells did not support the propagation of the AdΔVR vectors, HEK293 transformants inducibly expressing VA-RNA I (VR293 cells) with appropriate induction of VA-RNA I expression allowed the propagation of the AdΔVR vector. The AdΔVR vector showed high transduction efficiency comparable to that of the conventional FG-Ad vector in the cultured cells. The AdΔVR vector may be a safer alternative to the FG-Ad vector.
腺病毒（Ad）载体的使用存在一个主要限制，即固有免疫反应会导致炎症细胞因子的产生和组织损伤。为了克服这一限制，有必要开发更安全的 Ad 载体，使其不太可能引发固有免疫。Ad 基因组编码两种非编码小 RNA，即病毒相关（VA）-RNA I 和 VA-RNA II，它们由 RNA 聚合酶 III 转录，并促进 Ad 的复制。最近，我们报道 VA-RNAs 在被传统第一代（E1 缺失）Ad 载体（FG-Ad）转导的细胞中产生，并通过细胞内核酸传感器触发固有免疫反应。在本研究中，我们开发了一种 VA-RNA 缺失的 Ad（AdΔVR）载体，其中 VA-RNA 表达的转录控制元件被删除。虽然常规的 HEK293 细胞不支持 AdΔVR 载体的复制，但通过适当诱导 VA-RNA I 表达的可诱导表达 VA-RNA I 的 HEK293 转化体（VR293 细胞）允许 AdΔVR 载体的复制。与传统的 FG-Ad 载体相比，AdΔVR 载体在培养细胞中显示出相当高的转导效率。AdΔVR 载体可能是 FG-Ad 载体的更安全替代品。
