Project description:We evaluate CRISPR-based prime editing for application in organoids. First we model mutations in TP53 in intestinal and hepatocyte oganoids and determine the efficiency and accuracy of mutation induction on multiple targets. Then, to evaluate potential clinical applicability of prime editing we repair mutations in the CFTR channel that cause cystic fibrosis in intestinal organoids. First we repair the CFTR-F508del mutation which is the most common mutation in cystic fibrosis. Then we compare adenine base editing to prime editing by repairing the CFTR-R785* mutation using both strategies.
Project description:Optimization of CRISPR/Cas9-mediated genome engineering has resulted in base editors that hold promise for mutation repair and disease modeling. Here, we demonstrate the application of base editors for the generation of complex tumor models in human ASC-derived organoids. First we show Efficacy of cytosine and adenine base editors in modelingCTNNB1hot-spot mutations in hepatocyte organoids. Next, we use C>T base editors to insert nonsense mutations inPTENin endometrial organoids and demonstrate tumorigenicity even in the heterozygous state. Moreover, drug screening assays on organoids harboring eitherPTENorPTENandPIK3CAmutations reveal the mechanism underlying the initial stages of endometrial tumorigenesis. To further increase the scope of base editing we combine SpCas9 and SaCas9 for simultaneous C>T and A>G editing at individual target sites. Finally, we show that base editor multiplexing allow modeling of colorectal tumorigenesis in a single step by simultaneously transfecting sgRNAs targeting five cancer genes.
Project description:CRISPR gene editing has revolutionized biomedicine and biotechnology by providing a simple means to engineer genes in vivo by introducing mutations at target sites in the genomic DNA of living cells. However, given the stochasticity of cellular DNA repair mechanisms and the potential for introducing mutations at off-target sites, technologies capable of introducing targeted changes with increased precision, such as cytidine deaminase single-base editors, are preferred. We here present a versatile method termed CRISPR-SKIP that utilizes cytidine deaminase single-base editors to program de-novo exon skipping by mutating target DNA bases within splice acceptor sites. Given its simplicity and precision, CRISPR-SKIP will be broadly applicable in gene therapy and synthetic biology.
Project description:CRISPR gene editing has revolutionized biomedicine and biotechnology by providing a simple means to engineer genes in vivo by introducing mutations at target sites in the genomic DNA of living cells. However, given the stochasticity of cellular DNA repair mechanisms and the potential for introducing mutations at off-target sites, technologies capable of introducing targeted changes with increased precision, such as cytidine deaminase single-base editors, are preferred. We here present a versatile method termed CRISPR-SKIP that utilizes cytidine deaminase single-base editors to program de-novo exon skipping by mutating target DNA bases within splice acceptor sites. Given its simplicity and precision, CRISPR-SKIP will be broadly applicable in gene therapy and synthetic biology.
Project description:CRISPR gene editing has revolutionized biomedicine and biotechnology by providing a simple means to engineer genes in vivo by introducing mutations at target sites in the genomic DNA of living cells. However, given the stochasticity of cellular DNA repair mechanisms and the potential for introducing mutations at off-target sites, technologies capable of introducing targeted changes with increased precision, such as cytidine deaminase single-base editors, are preferred. We here present a versatile method termed CRISPR-SKIP that utilizes cytidine deaminase single-base editors to program de-novo exon skipping by mutating target DNA bases within splice acceptor sites. Given its simplicity and precision, CRISPR-SKIP will be broadly applicable in gene therapy and synthetic biology.
Project description:Emerging base and prime editing may provide safer and more precise genetic engineering than nuclease-based approaches bypassing the dependence on DNA double strand breaks (DSBs). However, little is known about cellular responses and genotoxicity. Here, we comparatively assessed state-of-the-art base and prime editors (B/PE) versus Cas9 in human hematopoietic stem/progenitor cells (HSPCs). BE and PE induced detrimental transcriptional responses constraining editing efficiency and/or HSPC repopulation in xenotransplants, albeit to a lesser extent than Cas9. DNA DSBs and their genotoxic byproducts, including deletions and translocations, were less frequent but not abrogated by BE and PE, particularly for cytidine BE due to suboptimal inhibition of base excision repair. Tailoring timing and B/PE expression enabled highly efficient and precise editing of long-term repopulating HSPCs. However, we uncovered a genome-wide effect of BEs on the mutational landscape of HSPCs, raising concerns for a potential genotoxic impact and calling for further investigations and improvements in view of clinical application.and/or HSPC repopulation in xenotransplants, albeit to a lesser extent than Cas9. DNA DSBs and their genotoxic byproducts, including deletions and translocations, were lower but not abrogated by BE and PE, particularly for cytidine BE upon suboptimal base excision repair inhibition. Tailoring timing and B/PE expression enabled highly efficient and precise editing of long-term repopulating HSPCs. However, we uncovered a genome-wide effect of cytidine BE on mutational landscape of hematopoietic grafts, raising concerns for its prospective clinical application. Conversely, the superior efficiency and precision of adenine BE built confidence on its entry into clinical arena.
Project description:Emerging base and prime editing may provide safer and more precise genetic engineering than nuclease-based approaches bypassing the dependence on DNA double strand breaks (DSBs). However, little is known about cellular responses and genotoxicity. Here, we comparatively assessed state-of-the-art base and prime editors (B/PE) versus Cas9 in human hematopoietic stem/progenitor cells (HSPCs). BE and PE induced detrimental transcriptional responses constraining editing efficiency and/or HSPC repopulation in xenotransplants, albeit to a lesser extent than Cas9. DNA DSBs and their genotoxic byproducts, including deletions and translocations, were less frequent but not abrogated by BE and PE, particularly for cytidine BE due to suboptimal inhibition of base excision repair. Tailoring timing and B/PE expression enabled highly efficient and precise editing of long-term repopulating HSPCs. However, we uncovered a genome-wide effect of BEs on the mutational landscape of HSPCs, raising concerns for a potential genotoxic impact and calling for further investigations and improvements in view of clinical application.
Project description:Emerging base and prime editing may provide safer and more precise genetic engineering than nuclease-based approaches bypassing the dependence on DNA double strand breaks (DSBs). However, little is known about cellular responses and genotoxicity. Here, we comparatively assessed state-of-the-art base and prime editors (B/PE) versus Cas9 in human hematopoietic stem/progenitor cells (HSPCs). BE and PE induced detrimental transcriptional responses constraining editing efficiency and/or HSPC repopulation in xenotransplants, albeit to a lesser extent than Cas9. DNA DSBs and their genotoxic byproducts, including deletions and translocations, were less frequent but not abrogated by BE and PE, particularly for cytidine BE due to suboptimal inhibition of base excision repair. Tailoring timing and B/PE expression enabled highly efficient and precise editing of long-term repopulating HSPCs. However, we uncovered a genome-wide effect of BEs on the mutational landscape of HSPCs, raising concerns for a potential genotoxic impact and calling for further investigations and improvements in view of clinical application.
Project description:Emerging base and prime editing may provide safer and more precise genetic engineering than nuclease-based approaches bypassing the dependence on DNA double strand breaks (DSBs). However, little is known about cellular responses and genotoxicity. Here, we comparatively assessed state-of-the-art base and prime editors (B/PE) versus Cas9 in human hematopoietic stem/progenitor cells (HSPCs). BE and PE induced detrimental transcriptional responses constraining editing efficiency and/or HSPC repopulation in xenotransplants, albeit to a lesser extent than Cas9. DNA DSBs and their genotoxic byproducts, including deletions and translocations, were less frequent but not abrogated by BE and PE, particularly for cytidine BE due to suboptimal inhibition of base excision repair. Tailoring timing and B/PE expression enabled highly efficient and precise editing of long-term repopulating HSPCs. However, we uncovered a genome-wide effect of BEs on the mutational landscape of HSPCs, raising concerns for a potential genotoxic impact and calling for further investigations and improvements in view of clinical application.
Project description:Emerging base and prime editing may provide safer and more precise genetic engineering than nuclease-based approaches bypassing the dependence on DNA double strand breaks (DSBs). However, little is known about cellular responses and genotoxicity. Here, we comparatively assessed state-of-the-art base and prime editors (B/PE) versus Cas9 in human hematopoietic stem/progenitor cells (HSPCs). BE and PE induced detrimental transcriptional responses constraining editing efficiency and/or HSPC repopulation in xenotransplants, albeit to a lesser extent than Cas9. DNA DSBs and their genotoxic byproducts, including deletions and translocations, were less frequent but not abrogated by BE and PE, particularly for cytidine BE due to suboptimal inhibition of base excision repair. Tailoring timing and B/PE expression enabled highly efficient and precise editing of long-term repopulating HSPCs. However, we uncovered a genome-wide effect of BEs on the mutational landscape of HSPCs, raising concerns for a potential genotoxic impact and calling for further investigations and improvements in view of clinical application.