Project description:C-to-T base editing mediated by CRISPR/Cas9 base editors (BEs) needs a G/C-rich PAM and the editing fidelity is compromised by unwanted indels and non-C-to-T substitutions. We developed CRISPR/Cpf1-based BEs to recognize a T-rich PAM and induce efficient C-to-T editing with few indels and/or non-C-to-T substitutions. The requirement of editing fidelity in therapeutic-related trials necessitates the development of CRISPR/Cpf1-based BEs, which also facilitates base editing in A/T-rich regions.
Project description:The targeting range of CRISPR-Cas9 base editors (BEs) is limited by their G/C-rich PAM sequences. To overcome this limitation, we developed a CRISPR/Cpf1-based BE by fusing the rat cytosine deaminase APOBEC1 to a catalytically inactive version of Lachnospiraceae bacterium Cpf1. The base editor recognizes a T-rich PAM sequence and converts C to T in human cells with low levels of indels, non-C-to-T substitutions and off-target editing.
Project description:Duchenne muscular dystrophy (DMD) is the most common fatal genetic disease. Clustered regularly interspaced short palindromic repeat (CRISPR)-mediated gene editing is a promising strategy for permanently curing DMD. In this study we developed a novel strategy for reframing DMD mutations by CRISPR-mediated large-scale excision of exons 46–54. We compared this approach to other DMD rescue strategies using DMD patient-derived primary muscle-derived stem cells (MDSCs) and found that it showed the highest efficiency in terms of restoring of dystrophin protein expression. We also confirmed that CRISPR from Prevotella and Francisella 1(Cpf1)-mediated genome editing could correct DMD mutation with higher specificity than CRISPR-associated protein 9 (Cas9). Furthermore, A patient-derived xenograft (PDX) DMD mouse model was established by transplanting DMD-MDSCs into immunodeficient mice. CRISPR gene editing components were intramuscularly delivered into the mouse model by adeno-associated virus vectors. Dystrophin expression levels were increased by 10%–30% in human DMD muscle fibers. The restored dystrophin in vivo was functional, as demonstrated by the expression of the dystrophin glycoprotein complex member β-dystroglycan. This study provides a sensitive indicator for in vivo efficacy of gene editing and lays the foundation for a clinical trial of DMD treatment with gene editing technology.
Project description:Duchenne muscular dystrophy (DMD) is the most common fatal genetic disease. Clustered regularly interspaced short palindromic repeat (CRISPR)-mediated gene editing is a promising strategy for permanently curing DMD. In this study we developed a novel strategy for reframing DMD mutations by CRISPR-mediated large-scale excision of exons 46–54. We compared this approach to other DMD rescue strategies using DMD patient-derived primary muscle-derived stem cells (MDSCs) and found that it showed the highest efficiency in terms of restoring of dystrophin protein expression. We also confirmed that CRISPR from Prevotella and Francisella 1(Cpf1)-mediated genome editing could correct DMD mutation with higher specificity than CRISPR-associated protein 9 (Cas9). Furthermore, A patient-derived xenograft (PDX) DMD mouse model was established by transplanting DMD-MDSCs into immunodeficient mice. CRISPR gene editing components were intramuscularly delivered into the mouse model by adeno-associated virus vectors. Dystrophin expression levels were increased by 10%–30% in human DMD muscle fibers. The restored dystrophin in vivo was functional, as demonstrated by the expression of the dystrophin glycoprotein complex member β-dystroglycan. This study provides a sensitive indicator for in vivo efficacy of gene editing and lays the foundation for a clinical trial of DMD treatment with gene editing technology.
Project description:Duchenne muscular dystrophy (DMD) is the most common fatal genetic disease. Clustered regularly interspaced short palindromic repeat (CRISPR)-mediated gene editing is a promising strategy for permanently curing DMD. In this study we developed a novel strategy for reframing DMD mutations by CRISPR-mediated large-scale excision of exons 46–54. We compared this approach to other DMD rescue strategies using DMD patient-derived primary muscle-derived stem cells (MDSCs) and found that it showed the highest efficiency in terms of restoring of dystrophin protein expression. We also confirmed that CRISPR from Prevotella and Francisella 1(Cpf1)-mediated genome editing could correct DMD mutation with higher specificity than CRISPR-associated protein 9 (Cas9). Furthermore, A patient-derived xenograft (PDX) DMD mouse model was established by transplanting DMD-MDSCs into immunodeficient mice. CRISPR gene editing components were intramuscularly delivered into the mouse model by adeno-associated virus vectors. Dystrophin expression levels were increased by 10%–30% in human DMD muscle fibers. The restored dystrophin in vivo was functional, as demonstrated by the expression of the dystrophin glycoprotein complex member β-dystroglycan. This study provides a sensitive indicator for in vivo efficacy of gene editing and lays the foundation for a clinical trial of DMD treatment with gene editing technology.
Project description:Duchenne muscular dystrophy (DMD) is the most common fatal genetic disease. Clustered regularly interspaced short palindromic repeat (CRISPR)-mediated gene editing is a promising strategy for permanently curing DMD. In this study we developed a novel strategy for reframing DMD mutations by CRISPR-mediated large-scale excision of exons 46–54. We compared this approach to other DMD rescue strategies using DMD patient-derived primary muscle-derived stem cells (MDSCs) and found that it showed the highest efficiency in terms of restoring of dystrophin protein expression. We also confirmed that CRISPR from Prevotella and Francisella 1(Cpf1)-mediated genome editing could correct DMD mutation with higher specificity than CRISPR-associated protein 9 (Cas9). Furthermore, A patient-derived xenograft (PDX) DMD mouse model was established by transplanting DMD-MDSCs into immunodeficient mice. CRISPR gene editing components were intramuscularly delivered into the mouse model by adeno-associated virus vectors. Dystrophin expression levels were increased by 10%–30% in human DMD muscle fibers. The restored dystrophin in vivo was functional, as demonstrated by the expression of the dystrophin glycoprotein complex member β-dystroglycan. This study provides a sensitive indicator for in vivo efficacy of gene editing and lays the foundation for a clinical trial of DMD treatment with gene editing technology.
Project description:Duchenne muscular dystrophy (DMD) is the most common fatal genetic disease. Clustered regularly interspaced short palindromic repeat (CRISPR)-mediated gene editing is a promising strategy for permanently curing DMD. In this study we developed a novel strategy for reframing DMD mutations by CRISPR-mediated large-scale excision of exons 46–54. We compared this approach to other DMD rescue strategies using DMD patient-derived primary muscle-derived stem cells (MDSCs) and found that it showed the highest efficiency in terms of restoring of dystrophin protein expression. We also confirmed that CRISPR from Prevotella and Francisella 1(Cpf1)-mediated genome editing could correct DMD mutation with higher specificity than CRISPR-associated protein 9 (Cas9). Furthermore, A patient-derived xenograft (PDX) DMD mouse model was established by transplanting DMD-MDSCs into immunodeficient mice. CRISPR gene editing components were intramuscularly delivered into the mouse model by adeno-associated virus vectors. Dystrophin expression levels were increased by 10%–30% in human DMD muscle fibers. The restored dystrophin in vivo was functional, as demonstrated by the expression of the dystrophin glycoprotein complex member β-dystroglycan. This study provides a sensitive indicator for in vivo efficacy of gene editing and lays the foundation for a clinical trial of DMD treatment with gene editing technology.