Lung Delivery Studies Using siRNA Conjugated to TAT(48-60) and Penetratin Reveal Peptide Induced Reduction in Gene Expression and Induction of Innate Immunity

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• 作者：Sterghios Athanasios Moschos ; Simon Wyn Jones ; Mark Michael Perry ; Andrew Evan Williams ; Jonas Sten Erjefalt ; John James Turner ; Peter John Barnes ; Brian Stephen Sproat ; Michael John Gait ; Mark Andrew
• 刊名：Bioconjugate Chemistry
• 出版年：2007
• 出版时间：September 2007
• 年：2007
• 卷：18
• 期：5
• 页码：1450 - 1459
• 全文大小：506K
• 年卷期：v.18,no.5(September 2007)
• ISSN：1520-4812

文摘

The therapeutic application of siRNA shows promise as an alternative approach to small-molecule inhibitors forthe treatment of human disease. However, the major obstacle to its use has been the difficulty in delivering theselarge anionic molecules in vivo. In this study, we have investigated whether siRNA-mediated knockdown of p38MAP kinase mRNA in mouse lung is influenced by conjugation to the nonviral delivery vector cholesterol andthe cell penetrating peptides (CPP) TAT(48-60) and penetratin. Initial studies in the mouse fibroblast L929 cellline showed that siRNA conjugated to cholesterol, TAT(48-60), and penetratin, but not siRNA alone, achieveda limited reduction of p38 MAP kinase mRNA expression. Intratracheal administration of siRNA resulted inlocalization within macrophages and scattered epithelial cells and produced a 30-45% knockdown of p38 MAPkinase mRNA at 6 h. As with increasing doses of siRNA, conjugation to cholesterol improved upon the durationbut not the magnitude of mRNA knockdown, while penetratin and TAT(48-60) had no effect. Importantly,administration of the penetratin or TAT(48-60) peptides alone caused significant reduction in p38 MAP kinasemRNA expression, while the penetratin-siRNA conjugate activated the innate immune response. Overall, thesestudies suggest that conjugation to cholesterol may extend but not increase siRNA-mediated p38 MAP kinasemRNA knockdown in the lung. Furthermore, the use of CPP may be limited due to as yet uncharacterized effectsupon gene expression and a potential for immune activation.