Genotoxicity profiling reveals distinct platform- and cell type–specific effects in therapeutic gene editing for genetic hyperinflammation
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE326932 | GEO | 2026/04/03
REPOSITORIES: GEO
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Project description:Hemophagocytic lymphohistiocytosis (HLH) is a hyperinflammatory disorder characterized by a life-threatening cytokine storm and immunopathology. Familial HLH type 3 (FHL3) accounts for 30% of all inborn HLH cases worldwide. It is caused by mutations in the UNC13D gene, which result in impaired processing of cytotoxic vesicles and hence compromised T and NK cell-mediated killing. Current treatment protocols, including allogeneic hematopoietic stem cell (HSC) transplantation, still show 30-40% mortality. As a first step to meet this medical need, we developed and tested a curative genome editing strategy in the FHL3 Jinx mouse model. Jinx mice harbor a cryptic splice donor site (cSD) in Unc13d intron 26 and develop the clinical symptoms of human FHL3 upon infection with lymphocytic choriomeningitis virus (LCMV). Here, we employed CRISPR-Cas technology to delete the disease-underlying mutation in HSCs, and transplanted the Unc13d-edited stem cells into busulfan-conditioned Jinx recipient mice. Genotyping, phenotyping and CAST-Seq based off-target analyses of cells isolated from transplanted mice revealed efficient gene editing (>95%), polyclonality of the T cell receptor repertoire, and neither signs of off-target effects nor leukemogenesis. Unc13d transcription levels of edited and wildtype cells were comparable. LCMV challenge of the transplanted mice resulted in acute HLH in Jinx mice transplanted with mock-edited HSCs, while Jinx mice grafted with Unc13d-edited cells showed rapid virus clearance and protection from HLH. In sum, our study demonstrates that transplantation of CRISPR-Cas edited HSCs supports the development of a functional polyclonal T cell response in the absence of genotoxicity-associated clonal outgrowth or leukemogenesis.
2023-07-04 | GSE225540 | GEO
Project description:Hemophagocytic lymphohistiocytosis (HLH) is a hyperinflammatory disorder characterized by a life-threatening cytokine storm and immunopathology. Familial HLH type 3 (FHL3) accounts for 30% of all inborn HLH cases worldwide. It is caused by mutations in the UNC13D gene, which result in impaired processing of cytotoxic vesicles and hence compromised T and NK cell-mediated killing. Current treatment protocols, including allogeneic hematopoietic stem cell (HSC) transplantation, still show 30-40% mortality. As a first step to meet this medical need, we developed and tested a curative genome editing strategy in the FHL3 Jinx mouse model. Jinx mice harbor a cryptic splice donor site (cSD) in Unc13d intron 26 and develop the clinical symptoms of human FHL3 upon infection with lymphocytic choriomeningitis virus (LCMV). Here, we employed CRISPR-Cas technology to delete the disease-underlying mutation in HSCs, and transplanted the Unc13d-edited stem cells into busulfan-conditioned Jinx recipient mice. Genotyping, phenotyping and CAST-Seq based off-target analyses of cells isolated from transplanted mice revealed efficient gene editing (>95%), polyclonality of the T cell receptor repertoire, and neither signs of off-target effects nor leukemogenesis. Unc13d transcription levels of edited and wildtype cells were comparable. LCMV challenge of the transplanted mice resulted in acute HLH in Jinx mice transplanted with mock-edited HSCs, while Jinx mice grafted with Unc13d-edited cells showed rapid virus clearance and protection from HLH. In sum, our study demonstrates that transplantation of CRISPR-Cas edited HSCs supports the development of a functional polyclonal T cell response in the absence of genotoxicity-associated clonal outgrowth or leukemogenesis.
2023-07-04 | GSE225534 | GEO
Project description:Hemophagocytic lymphohistiocytosis (HLH) is a hyperinflammatory disorder characterized by a life-threatening cytokine storm and immunopathology. Familial HLH type 3 (FHL3) accounts for 30% of all inborn HLH cases worldwide. It is caused by mutations in the UNC13D gene, which result in impaired processing of cytotoxic vesicles and hence compromised T and NK cell-mediated killing. Current treatment protocols, including allogeneic hematopoietic stem cell (HSC) transplantation, still show 30-40% mortality. As a first step to meet this medical need, we developed and tested a curative genome editing strategy in the FHL3 Jinx mouse model. Jinx mice harbor a cryptic splice donor site (cSD) in Unc13d intron 26 and develop the clinical symptoms of human FHL3 upon infection with lymphocytic choriomeningitis virus (LCMV). Here, we employed CRISPR-Cas technology to delete the disease-underlying mutation in HSCs, and transplanted the Unc13d-edited stem cells into busulfan-conditioned Jinx recipient mice. Genotyping, phenotyping and CAST-Seq based off-target analyses of cells isolated from transplanted mice revealed efficient gene editing (>95%), polyclonality of the T cell receptor repertoire, and neither signs of off-target effects nor leukemogenesis. Unc13d transcription levels of edited and wildtype cells were comparable. LCMV challenge of the transplanted mice resulted in acute HLH in Jinx mice transplanted with mock-edited HSCs, while Jinx mice grafted with Unc13d-edited cells showed rapid virus clearance and protection from HLH. In sum, our study demonstrates that transplantation of CRISPR-Cas edited HSCs supports the development of a functional polyclonal T cell response in the absence of genotoxicity-associated clonal outgrowth or leukemogenesis.
2023-07-04 | GSE225269 | GEO
Project description:CRISPR-guided DNA base editors enable the efficient installation of targeted single-nucleotide changes. Cytosine or adenine base editors (CBEs or ABEs), which are fusions of cytidine or adenosine deaminases to CRISPR-Cas nickases, can efficiently induce DNA C-to-T or A-to-G alterations in DNA, respectively. We recently demonstrated that both the widely used CBE BE3 (harboring a rat APOBEC1 cytidine deaminase) and the optimized ABEmax editor can induce tens of thousands of guide RNA-independent, transcriptome-wide RNA base edits in human cells with high efficiencies. In addition, we showed the feasibility of creating SElective Curbing of Unwanted RNA Editing (SECURE)-BE3 variants that exhibit substantially reduced unwanted RNA editing activities while retaining robust and more precise on-target DNA editing. Here we describe structure-guided engineering of SECURE-ABE variants that not only possess reduced off-target RNA editing with comparable on-target DNA activities but are also the smallest Streptococcus pyogenes Cas9 (SpCas9) base editors described to date. In addition, we tested CBEs composed of cytidine deaminases other than APOBEC1 and found that human APOBEC3A (hA3A) cytidine deaminase CBE induces substantial transcriptome-wide RNA base edits with high efficiencies. By contrast, a previously described “enhanced” A3A (eA3A) cytidine deaminase CBE or a human activation-induced cytidine deaminase (hAID) CBE induce substantially reduced or near background levels of RNA edits. In sum, our work describes broadly useful SECURE-ABE and -CBE base editors and reinforces the importance of minimizing RNA editing activities of DNA base editors for research and therapeutic applications.
2019-07-11 | GSE129893 | GEO
Project description:CRISPR-guided DNA base editors enable the efficient installation of targeted single-nucleotide changes. Cytosine or adenine base editors (CBEs or ABEs), which are fusions of cytidine or adenosine deaminases to CRISPR-Cas nickases, can efficiently induce DNA C-to-T or A-to-G alterations in DNA, respectively. We recently demonstrated that both the widely used CBE BE3 (harboring a rat APOBEC1 cytidine deaminase) and the optimized ABEmax editor can induce tens of thousands of guide RNA-independent, transcriptome-wide RNA base edits in human cells with high efficiencies. In addition, we showed the feasibility of creating SElective Curbing of Unwanted RNA Editing (SECURE)-BE3 variants that exhibit substantially reduced unwanted RNA editing activities while retaining robust and more precise on-target DNA editing. Here we describe structure-guided engineering of SECURE-ABE variants that not only possess reduced off-target RNA editing with comparable on-target DNA activities but are also the smallest Streptococcus pyogenes Cas9 (SpCas9) base editors described to date. In addition, we tested CBEs composed of cytidine deaminases other than APOBEC1 and found that human APOBEC3A (hA3A) cytidine deaminase CBE induces substantial transcriptome-wide RNA base edits with high efficiencies. By contrast, a previously described “enhanced” A3A (eA3A) cytidine deaminase CBE or a human activation-induced cytidine deaminase (hAID) CBE induce substantially reduced or near background levels of RNA edits. In sum, our work describes broadly useful SECURE-ABE and -CBE base editors and reinforces the importance of minimizing RNA editing activities of DNA base editors for research and therapeutic applications.
2019-07-11 | GSE129889 | GEO
Project description:CRISPR-Cas base editor technology enables targeted nucleotide alterations and is being rapidly deployed for research and potential therapeutic applications. The most widely used base editors induce DNA cytosine (C) deamination with rat APOBEC1 (rAPOBEC1) enzyme, which is targeted by a linked Cas protein-guide RNA (gRNA) complex. Previous studies of cytosine base editor (CBE) specificity have identified off-target DNA edits in human cells. Here we show that a CBE with rAPOBEC1 can cause extensive transcriptome-wide RNA cytosine deamination in human cells, inducing tens of thousands of C-to-uracil (U) edits with frequencies ranging from 0.07% to 100% in 38% - 58% of expressed genes. CBE-induced RNA edits occur in both protein-coding and non-protein-coding sequences and generate missense, nonsense, splice site, 5’ UTR, and 3’ UTR mutations. We engineered two CBE variants bearing rAPOBEC1 mutations that substantially decrease the numbers of RNA edits (reductions of >390-fold and >3,800-fold) in human cells. These variants also showed more precise on-target DNA editing and, with the majority of gRNAs tested, editing efficiencies comparable to those observed with wild-type CBE. Finally, we show that recently described adenine base editors (ABEs) can also induce transcriptome-wide RNA edits. These results have important implications for the research and therapeutic uses of base editors, illustrate the feasibility of engineering improved variants with reduced RNA editing activities, and suggest the need to more fully define and characterize the RNA off-target effects of deaminase enzymes in base editor platforms. This SuperSeries is composed of the SubSeries listed below.
2019-03-31 | GSE121668 | GEO
Project description:CRISPR-Cas base editor technology enables targeted nucleotide alterations and is being rapidly deployed for research and potential therapeutic applications. The most widely used base editors induce DNA cytosine (C) deamination with rat APOBEC1 (rAPOBEC1) enzyme, which is targeted by a linked Cas protein-guide RNA (gRNA) complex. Previous studies of cytosine base editor (CBE) specificity have identified off-target DNA edits in human cells. Here we show that a CBE with rAPOBEC1 can cause extensive transcriptome-wide RNA cytosine deamination in human cells, inducing tens of thousands of C-to-uracil (U) edits with frequencies ranging from 0.07% to 100% in 38% - 58% of expressed genes. CBE-induced RNA edits occur in both protein-coding and non-protein-coding sequences and generate missense, nonsense, splice site, 5’ UTR, and 3’ UTR mutations. We engineered two CBE variants bearing rAPOBEC1 mutations that substantially decrease the numbers of RNA edits (reductions of >390-fold and >3,800-fold) in human cells. These variants also showed more precise on-target DNA editing and, with the majority of gRNAs tested, editing efficiencies comparable to those observed with wild-type CBE. Finally, we show that recently described adenine base editors (ABEs) can also induce transcriptome-wide RNA edits. These results have important implications for the research and therapeutic uses of base editors, illustrate the feasibility of engineering improved variants with reduced RNA editing activities, and suggest the need to more fully define and characterize the RNA off-target effects of deaminase enzymes in base editor platforms.
2019-03-31 | GSE126502 | GEO
Project description:CRISPR-Cas base editors are preferred tool for genome editing as they generate desired editing without any double strand break in the genome, as double stand break is detrimental to the cells. In our study we have demonstrated the significance of base editors in editing the highly homologous HBG promoter (HBG1 and HBG2) region to introduce novel HPFH-like mutation to elevate HbF for therapeutical applications. Previous studies revealed that the base editors can cause unintended Cas-independent edits at transcriptome level. To validate off-target at RNA level, we performed a transcriptome wide analysis. The frequency of unintended edits in the HUDEP-2 stable cell lines expressing the base editors with the gRNA were not significant compared to the control. We determined the ABE mediated A to I conversion and CBE mediated C to U conversion across the base edited samples. The RNA off-target analysis was carried out with the help of REDItools v 2 tool. This data suggests that despite high on-target editing in DNA, the Cas-independent RNA off-target were not at detectable range compared to control. The differential expression of 34 selected genes which necessitate globin regulation were compared between the unedited HUDEP WT, CBE control, ABE control, and edited ABE (with gRNA 2/11) and edited CBE (with gRNA 2/11). We observed that there is no significant differential gene expression between the edited and control cells except the gamma and delta globin genes. These results suggest that base editors are preferred tools to edit highly homologous HBG promoter region to created HPFH-like mutations inducing HbF levels without causing double strand breaks, larger deletions and no significant RNA off-targets which are detrimental to the gene edited cells.
2022-01-02 | GSE192801 | GEO
Project description:Base Editing has been touted the most intelligent and precise application of the CRISPR platform so far, merging the simplicity of RNA-guided nucleases with deaminases that allow for the programmable generation of single base substitutions - without introduction of double-strand breaks. Even though the two-component system has been expected to cause off-target substitutions, studies involving cytosine base editors (CBEs) showed that in most cases, relatively few single base off-targets could be detected on DNA. We introduce the concept of multi-dimensional off-targeting, presenting an extensive amount of RNA cytidines being edited by DNA base editors. Epitranscriptomic off-target effects affected different cell lines and were independent of the guide RNAs used, suggesting Cas9-independent activity of the cytidine deaminase rAPOBEC1 on single-stranded RNA. With the help of protein engineering, we developed CBE variants with massively reduced inadvertent mutation of RNA that preserve and enhance DNA base editing capabilities.
2019-03-31 | GSE121666 | GEO
Project description:Base Editing has been touted the most intelligent and precise application of the CRISPR platform so far, merging the simplicity of RNA-guided nucleases with deaminases that allow for the programmable generation of single base substitutions - without introduction of double-strand breaks. Even though the two-component system has been expected to cause off-target substitutions, studies involving cytosine base editors (CBEs) showed that in most cases, relatively few single base off-targets could be detected on DNA. We introduce the concept of multi-dimensional off-targeting, presenting an extensive amount of RNA cytidines being edited by DNA base editors. Epitranscriptomic off-target effects affected different cell lines and were independent of the guide RNAs used, suggesting Cas9-independent activity of the cytidine deaminase rAPOBEC1 on single-stranded RNA. With the help of protein engineering, we developed CBE variants with massively reduced inadvertent mutation of RNA that preserve and enhance DNA base editing capabilities.
2019-03-31 | GSE121665 | GEO