Delivery of RNAi Therapeutics to the Airways—From Bench to Bedside

Qiu, Yingshan; Lam, Jenny K. W.; Leung, Susan W. S.; Liang, Wanling

Lung diseases are among the leading causes of death worldwide. Current treatment of lung diseases such as lung cancer [1] , respiratory infections [2, 3] , inflammatory diseases [4, 5] and pulmonary fibrosis [6] have limited efficacy. Almost two decades ago, double-stranded RNAs (dsRNAs) were discovered to play an important role in regulating gene functions by a sequence-specific post-transcriptional gene silencing mechanism called RNA interference (RNAi) [7] . The therapeutic potential of RNAi was soon realized. It presents a new and powerful approach to treat or prevent many diseases including respiratory disorders by modulating gene expression [8] [9] [10] [11] [12] [13] . RNAi can be mediated by various types of RNA molecules, including long dsRNA, short interfering RNA (siRNA), short hairpin RNA (shRNA) and microRNA (miRNA). The mechanism of RNAi is illustrated in Figure 1 , and the general properties of different types of RNAi molecules are summarized in Table 1 .