Abstract：
Selective and sensitive imaging of intracellular mature microRNAs (miRNAs) is of great importance for biological process study and medical diagnostics. However, this goal remains challenging because of the interference of precursor miRNAs (pre-miRNAs) and the low abundance of mature miRNAs. Herein, we develop an endogenous enzyme-driven amplified DNA nanocage probe (Acage) for the selective and sensitive imaging of mature miRNAs in living cells. The Acage consists of a microRNA-responsive probe, an endogenous enzyme-driven fuel strand, and a DNA nanocage framework with an inner cavity. Benefiting from the size selectivity of DNA nanocage, smaller mature miRNAs rather than larger pre-miRNAs are allowed to enter the cavity of DNA nanocage for molecular recognition; thus, Acage can significantly reduce the signal interference of pre-miRNAs. Moreover, with the driving force of an endogenous enzyme apurinic/apyrimidinic endonuclease 1 (APE1) for efficient signal amplification, Acage enables sensitive intracellular miRNA imaging without an additional external intervention. With these features, Acage was successfully applied for intracellular imaging of mature miRNAs during drug treatment. We believe that this strategy provides a promising pathway for better understanding the functions of mature microRNAs in biological processes and medical diagnostics.
摘要：
细胞内成熟microRNAs（miRNAs）的选择性和灵敏成像对于生物过程研究和医学诊断具有重要意义。然而,由于前体miRNA（pre-miRNA）的干扰和成熟miRNA的低丰度，这一目标仍然具有挑战性。在这里，我们开发了一种内源性酶驱动的扩增DNA纳米笼探针（Acage），用于活细胞中成熟miRNA的选择性和灵敏成像。Acage由microRNA响应探针组成，内源性酶驱动的燃料链，和具有内腔的DNA纳米笼框架。受益于DNA纳米笼的尺寸选择性，允许较小的成熟miRNAs而不是较大的pre-miRNAs进入DNA纳米笼的空腔进行分子识别；因此，acage可以显著降低pre-miRNAs的信号干扰。此外，利用内源性酶嘌呤/嘧啶核酸内切酶1（APE1）的驱动力进行有效的信号放大，acage能够在没有额外外部干预的情况下进行敏感的细胞内miRNA成像。有了这些功能，Acage已成功应用于药物治疗期间成熟miRNA的细胞内成像。我们相信这种策略为更好地理解成熟microRNA在生物过程和医学诊断中的功能提供了有希望的途径。
