Project description:To develop a new therapeutic strategy for cardiac ischemia/reperfusion injury, we ablated the oxidative activation site of CaMKIIδ in the heart using CRISPR-Cas9 adenine base editing technology. Adult C57Bl6 mice were subjected to control surgery (IR-Sham, 3 biological replicates) or ischemia/reperfusion injury with either no injection (IR, 3 biological replicates), injection of a control virus (IR-Virus control, 3 biological replicates) or injection of a functional CaMKIIδ editing system (IR-Edit, 4 biological replicates). Five weeks after the surgery, hearts were harvested for RNA isolation and subsequent bulk RNA sequencing and gene expression profiling analysis.
Project description:CRISPR-enabled genetic screening is a powerful tool to discover genes that control T cell function and has nominated candidate target genes for immunotherapies1–6. However, new approaches are required to probe specific nucleotide sequences within key genes. Systematic mutagenesis in primary human T cells could discover alleles that tune specific phenotypes. DNA base editors are powerful tools to introduce targeted mutations with high efficiency7,8. Here, we develop a large-scale base editing mutagenesis platform with the goal of pinpointing nucleotides encoding amino acid residues that tune primary human T cell activation responses. We generated a library of ~117,000 sgRNAs targeting base editors to protein coding sites across 385 genes implicated in T cell function and systematically identified protein domains and specific amino acid residues that regulate T cell activation and cytokine production. We discovered a broad spectrum of alleles with variants encoding critical residues (in PIK3CD, VAV1, LCP2, PLCG1 and DGKZ and others), comprising both gain-of-function and loss-of-function mutations. We validated the functional effects of diverse alleles and further demonstrated that base edit hits could positively and negatively tune T cell cytotoxic function. Finally, higher-resolution screening using a base editor with relaxed PAM requirements9 (NG versus NGG) revealed specific structural domains and protein-protein interaction sites that can be targeted to tune T cell functions. Base editing screens in primary immune cells provide biochemical insights with potential to accelerate immunotherapy design.
Project description:Duchenne muscular dystrophy is an X-linked monogenic disease caused by mutations in the dystrophin gene (DMD) and characterized by progressive muscle weakness leading to loss of ambulation and significantly decreased life expectancy. Since the current standard of care for Duchenne muscular dystrophy is to merely treat symptoms, there is a dire need for novel treatment modalities that can correct the underlying genetic mutations. While several gene replacement therapies are being explored in clinical trials, one emerging approach that can directly correct mutations in genomic DNA is base editing. We have recently developed CRISPR-SKIP, a base editing strategy to induce permanent exon skipping by introducing C>T or A>G mutations at splice acceptors in genomic DNA, which can be utilized therapeutically to recover dystrophin expression when a genomic deletion leads to an out-of-frame DMD transcript. We now demonstrate that CRISPR-SKIP can be adapted to correct some forms of Duchenne muscular dystrophy by disrupting the splice acceptor in human DMD exon 45 with high efficiency, which enables open reading frame recovery and restoration of dystrophin expression. We also demonstrate that AAV-delivered split-intein base editors edit the splice acceptor of DMD exon 45 in cultured human cells and in vivo, highlighting the therapeutic potential of this strategy.
Project description:We engineered circular ADAR recruiting guide RNAs (cadRNAs) that efficiently recruit endogenous ADARs to edit specific sites on target RNA
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.
Project description:rs16851030, a single-nucleotide variant located in the 3’-untranslated region of the ADORA1 gene, has been proposed as a potential marker of caffeine sensitivity in apnea of prematurity, aspirin-induced asthma, and the development of acute chest syndrome. However, its functional significance is still unconfirmed. This study aimed to elucidate the functional impact of rs16851030 by using CRISPR/Cas9 approach to induce physiological changes associated with the DNA variant. rs16851030 was introduced into HEK293 cells through homology-directed repair. Edited cells were then fluorescence-enriched, sorted, isolated, and grown into single cell-derived clones. The single-base edit was confirmed by Sanger sequencing. Finally, RNA sequencing was performed to elucidate the pathways affected by rs16851030. Our study provides valuable information about key pathways associated with rs16851030 DNA variant.
Project description:Microarray hybridization was used to compare RNA from mouse brains with opposite genotypes at the Mvb1 (Nxf1) modifier locus for known alternative processing events. 6 samples of total brain RNA, from 3 littermate pairs, were hybridized to splicing-sensitive microarrays *Addendum Depending on the analysis software used, these CEL files may not load correctly using default parameters. This is due to the custom chip type of MJAY not being used during the array scanning step. There are three workarounds known for this problem so far. 1) If using APT, use multiple --chip-type parameters. Specifically, --chip-type mjay --chip-type MJAY --chip-type MoEx-1_0-st-v1.1sq 2) Edit the CEL file by converting to text using the APT command apt-cel-convert, then replacing the MoEx-1_0-st-v1.1sq in the DatHeader line with MJAY (all caps). 3) Edit the .pgf, .clf, and antigenomics.bmp files to use the MoEx-1_0-st-v1.1sq array instead of MJAY for the chip_type and lib_set_name options. (works on AltAnalyze software)
Project description:At the base of the intestinal crypt, long-lived Lgr5+ stem cells are intercalated by Paneth cells that provide essential niche signals for stem-cell maintenance. This unique epithelial anatomy makes the intestinal crypt one of the most accessible models for the study of adult stem cell biology. The glycosylation patterns of this compartment are poorly characterized and the impact of glycans on stem cell differentiation remains largely unexplored. We found that Paneth cells, but not Lgr5+ stem cells, express abundant terminal N-acetyllactosamine (LacNAc). Employing an enzymatic method to edit glycans in cultured crypt organoids, we assessed the functional role of LacNAc in the intestinal crypt. We show that blocking access to LacNAc on Paneth cells leads to hyperproliferation of the neighbouring Lgr5+ stem cells, which is accompanied by the down-regulation of genes that are known as negative regulators of proliferation
2017-12-27 | GSE108512 | GEO
Project description:Classification of ADAR1 p150 and p110 edit sites