Bi-directional gene activation and repression promote ASC differentiation and enhance bone healing in osteoporotic rats

• Published in: Molecular therapy Vol. 30; no. 1; pp. 92 - 104
• Main Authors: Truong, Vu Anh, Lin, Ya-Hui, Nguyen, Nuong Thi Kieu, Hsu, Mu-Nung, Pham, Nam Ngoc, Chang, Yi-Hao, Chang, Chin-Wei, Shen, Chih-Che, Lee, Hsiang-Sheng, Lai, Po-Liang, Parfyonova, Yelena V., Menshikov, Mikhail, Wu, Jaw-Ching, Chang, Yu-Han, Hu, Yu-Chen
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 05.01.2022; American Society of Gene & Cell Therapy
• Subjects: Adipose Tissue; Animals; bi-direction gene regulation; Bone Regeneration - genetics; Cell Differentiation - genetics; Chondrogenesis - genetics; CRISPR-AceTran; CRISPR-BiD; CRISPRi; Humans; Original; Rats; regenerative medicine; Stem Cells; Transcriptional Activation; CRISPR-BiD; CRISPRi; bi-direction gene regulation; CRISPR-AceTran; regenerative medicine
• ISSN: 1525-0016; 1525-0024
• DOI: 10.1016/j.ymthe.2021.08.024

Calvarial bone healing is challenging, especially for individuals with osteoporosis because stem cells from osteoporotic patients are highly prone to adipogenic differentiation. Based on previous findings that chondrogenic induction of adipose-derived stem cells (ASCs) can augment calvarial bone healing, we hypothesized that activating chondroinductive Sox Trio genes (Sox5, Sox6, Sox9) and repressing adipoinductive genes (C/ebp-α, Ppar-γ) in osteoporotic ASCs can reprogram cell differentiation and improve calvarial bone healing after implantation. However, simultaneous gene activation and repression in ASCs is difficult. To tackle this problem, we built a CRISPR-BiD system for bi-directional gene regulation. Specifically, we built a CRISPR-AceTran system that exploited both histone acetylation and transcription activation for synergistic Sox Trio activation. We also developed a CRISPR interference (CRISPRi) system that exploited DNA methylation for repression of adipoinductive genes. We combined CRISPR-AceTran and CRISPRi to form the CRISPR-BiD system, which harnessed three mechanisms (transcription activation, histone acetylation, and DNA methylation). After delivery into osteoporotic rat ASCs, CRISPR-BiD significantly enhanced chondrogenesis and in vitro cartilage formation. Implantation of the engineered osteoporotic ASCs into critical-sized calvarial bone defects significantly improved bone healing in osteoporotic rats. These results implicated the potential of the CRISPR-BiD system for bi-directional regulation of cell fate and regenerative medicine. [Display omitted] Truong et al. developed a CRISPR-based platform that harnessed three mechanisms (transcription activation, histone acetylation, and DNA methylation) for bi-directional gene manipulation to promote chondrogenic differentiation in vitro and bone regeneration in osteoporotic rat models.