双功能小分子调节microRNA的生物合成

MicroRNA是一类长度约为22个核苷酸的非编码小分子RNA。它们可以通过与靶标mRNA互补配对抑制其翻译或诱导降解，从而在转录水平上对基因表达进行调控。MicroRNA参与到动物体发育，细胞增殖、凋亡和分化等多种过程，在生命活动中扮演着非常重要的角色。许多疾病与microRNA的表达紊乱有关，因此microRNA被视为治疗疾病的一种新型靶标分子。

目前，调节microRNA的方法主要是使用经化学修饰的反义RNA。通过形成互补配对，反义RNA可对microRNA的功能进行抑制，然而由于其相对较差的细胞膜穿透能力和细胞毒性等缺点，该方法在实际应用中受到了很大的限制。于是人们尝试用小分子去抑制microRNA的生物合成过程，以期实现对其表达水平的调节。MicroRNA的生物合成是涉及多个步骤的复杂过程，其中包括限制性内切酶Dicer对microRNA前体（pre-miRNA）的剪切（Figure 1）。如果小分子可识别pre-miRNA而对其与Dicer间的相互作用进行干扰，将有望用作microRNA抑制剂。然而小分子通常很难有效扰乱生物大分子之间较强的相互作用，这使小分子microRNA抑制剂的研发非常困难。

Figure 1. Schematic illustration of the new approach to regulate miRNA biogenesis by using bifunctional small molecule that target pre-miRNA.

美国新墨西哥大学Fu-Sen Liang博士（点击查看介绍）研究组近期设计了一种利用小分子抑制microRNA生物合成的新策略。通过将可结合pre-miRNA的小分子与具有抑制核酸酶活性的功能基团进行连接，利用小分子对pre-miRNA的识别结合能力，他们可将核酸酶抑制剂准确投送至Dicer的活性位点，从而抑制其剪切pre-miRNA的能力，达到降低microRNA表达水平的目的（Figure 1）。基于此设计，他们将可识别致癌性miRNA-21前体的小分子与一种核酸酶抑制剂进行连接，构建了一系列的双功能分子。其中部分分子在体外与细胞水平证明可对miRNA-21的生物合成进行有效抑制（Figure 2），从而证实了这一策略的可行性。得益于该策略的模块化设计，他们只要简单更换RNA识别单元为可结合其他pre-miRNA的小分子，即可创造出抑制相应microRNA的双功能分子。这将为探索microRNA功能以及相关疾病治疗提供更多的小分子工具。该研究成果近期刊发于Journal of the American Chemical Society 上。

Figure 2. (a) RT-qPCR analysis of mature miR-21 expression levels. (b) Representative image of Western blotting analysis of PDCD₄ levels in pre-miR-21 expressing HEK293T cells with or without 7A treatment. (c) Densitometric quantitative analysis of PDCD₄ levels from three independent assays as in (b). The error bars represent the standard error of mean (N = 3).

该论文作者为：Hao Yan, Umesh Bhattarai, Zhi-Fo Guo and Fu-Sen Liang

原文（扫描或长按二维码，识别后直达原文页面，或点此查看原文）：

Regulating miRNA-21 Biogenesis By Bifunctional Small Molecules

J. Am. Chem. Soc., 2017, 139, 4987, DOI: 10.1021/jacs.7b00610

团队介绍

Principal Investigator

Fu-Sen Liang, Ph.D.

Assistant Professor

Department of Chemistry and Chemical Biology

University of New Mexico

Clark Hall R346

MSC03 2060 1 UNM

Albuquerque, NM 87131

Phone: 505-277-6655

Email: fsliang@unm.edu

Webpage: http://lianglab.unm.edu/

•BS in Chemistry, National Taiwan University

•MS in Organic Chemistry, National Chiao Tung University

•PhD in Bioorganic Chemistry, The Scripps Research Institute, La Jolla, CA

•Postdoc in Chemical Biology, Stanford Medical School

Fu-Sen was born in Taipei, Taiwan. After receiving his BS in Chemistry, he conducted MS research in natural product synthesis under the guidance of Dr. Tse-Lok Ho.

He then joined the Scripps Research Institute in La Jolla for PhD studies in Dr. Chi-Huey Wong's group where he designed and synthesized RNA-targeting small molecules and developed binding and specificity assays.

He did a postdoctoral research with Dr. Gerald Crabtree at Stanford Medical School where he investigated the functions of Brg chromatin remodeling complex and developed a new chemically induced proximity technique based on abscisic acid.

He moved to UNM at 2012 to start his independent research group. His research focuses on the development of novel chemical biology tools for biomedical research.

Research

Liang lab is an interdisciplinary research group that applies the concept of controlling proximity between molecules to regulate their interactions and downstream biological effects. They combine the techniques of synthetic chemistry, biochemistry, molecular biology, imaging and bioengineering to develop novel tools and molecules to study important biological questions and to develop novel therapies.

The current focuses in the lab include:

1. Develop new strategies for spatiotemporal regulation of microRNAs and long non-coding RNAs.

2. Engineering novel biological functions in mammalian systems using chemical and synthetic biology approaches.

The tools will be applied to study cancer biology and synaptic plasticity and develop new therapeutic strategies.