CRISPR技术发展及其在骨和软骨组织工程中的应用

Development of CRISPR technology and its application in bone and cartilage tissue engineering

由Cas9核酸酶和单向导RNA(sgRNA)组成的CRISPR/Cas9系统,可对sgRNA靶向的DNA序列进行缺失、插入和点突变等基因重编程操作,是新兴的基因编辑技术。此外,CRISPR/dCas9(Cas9核酸酶活性丧失的突变体),仍保留sgRNA靶向结合DNA的能力,dCas9蛋白融合转录激活物(CRISPRa)后可激活目标基因表达,也可通过融合转录阻遏物(CRISPRi)抑制目标基因表达。CRISPR/Cas9系统的高效输送是限制其临床广泛应用的主要问题之一。病毒载体被广泛用于递送CRISPR/Cas9元件;但就安全性、简便性和灵活性而言,非病毒载体研究更具吸引力。本文主要总结了CRISPR技术的原理和研究进展,包括CRISPR/Cas9的递送载体,递送模式以及递送过程的障碍,并回顾基于CRISPR技术在骨和软骨组织工程中的研究进展,讨论CRISPR技术在骨和软骨组织工程应用中面临的挑战和未来。

The CRISPR/Cas9 system, consisting of Cas9 nuclease and single guide RNA(sgRNA), is an emerging gene editing technology that can perform gene reprogramming operations such as deletion, insertion, and point mutation on DNA sequences targeted by sgRNA. In addition, CRISPR/dCas9(a mutant that loses Cas9 nuclease activity) still retains the ability of sgRNA to target DNA. The fusion of dCas9 protein with transcriptional activator(CRISPRa) can activate the expression of the target gene, and fusion transcriptional repressors(CRISPRi) can also be used to suppress target gene expression. Efficient delivery of the CRISPR/Cas9 system is one of the main problems limiting its wide clinical application. Viral vectors are widely used to efficiently deliver CRISPR/Cas9 elements, but non-viral vector research is more attractive in terms of safety, simplicity,and flexibility. In this review, we summarize the principles and research advances of CRISPR technology, including CRISPR/Cas9 delivery vectors, delivery methods, and obstacles to the delivery, and review the progress of CRISPR-based research in bone and cartilage tissue engineering. Finally, the challenges and future applications of CRISPR technology in bone and cartilage tissue engineering are discussed.