The innate immune response is an essential defense mechanism that allows cells to detect pathogen-associated molecular patterns (PAMPs) like endotoxin or cytosolic DNA and then induce the expression of defensive genes that restrict the replication of viruses and other pathogens. However, the therapeutic DNA used in some gene therapy treatments can also trigger the innate immune response, which activates host cell genes that may inhibit transgene expression. The goal of this study was to enhance transgene expression by inhibiting key components of the innate immune response with small molecule inhibitors (iCRT14, curcumin, Amlexanox, H-151, SC-514, & VX-702). Most of the inhibitors significantly increased transgene (luciferase) expression at least 2-fold, but the β-catenin/TCF4 inhibitor iCRT14 showed the highest enhancement (16 to 35-fold) in multiple cell lines (PC-3, MCF7, & MB49) without significantly decreasing cellular proliferation. Alternatively, cloning a β-catenin/TCF4 binding motif (TCAAAG) into the EF1α promoter also enhanced transgene expression up to 8-fold. To further investigate the role of β-catenin/TCF4 in transgene expression, mRNA-sequencing experiments were conducted to identify host cell genes that were upregulated following transfection with PEI but down-regulated after the addition of iCRT14. As expected, transfection with plasmid DNA activated the innate immune response and upregulated hundreds (687) of defensive genes, but only 7 of those genes were down-regulated in the presence of iCRT14 (e.g., PTGS2 & PLA1A). Altogether, these results show that transgene expression can be enhanced by inhibiting the innate immune response with SMIs like iCRT14, which inhibits β-catenin/TCF4 to prevent the expression of specific host cell genes.

先天免疫反应是一种重要的防御机制，它允许细胞检测病原体相关分子模式 (PAMP)，如内毒素或胞质 DNA，然后诱导防御基因的表达，从而限制病毒和其他病原体的复制。然而，一些基因治疗中使用的治疗性 DNA 也可以触发先天免疫反应，从而激活可能抑制转基因表达的宿主细胞基因。本研究的目标是通过使用小分子抑制剂（iCRT14、姜黄素、Amlexanox、H-151、SC-514 和 VX-702）抑制先天免疫反应的关键成分来增强转基因表达。大多数抑制剂显着增加转基因（荧光素酶）表达至少 2 倍，但是 β-catenin/TCF4 抑制剂 iCRT14 在多种细胞系（PC-3、MCF7 和 MB49）中表现出最高的增强作用（16 到 35 倍），而没有显着降低细胞增殖。或者，将 β-连环蛋白/TCF4 结合基序 (TCAAAG) 克隆到 EF1α 启动子中也将转基因表达增强了 8 倍。为了进一步研究 β-catenin/TCF4 在转基因表达中的作用，进行了 mRNA 测序实验以鉴定在用 PEI 转染后上调但在添加 iCRT14 后下调的宿主细胞基因。正如预期的那样，用质粒 DNA 转染激活先天免疫反应并上调数百 (687) 个防御基因，但在 iCRT14（例如 PTGS2 和 PLA1A）存在的情况下，这些基因中只有 7 个下调。共，