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:Gene expression profiles were recorded from rectal suction specimens of Cystic Fibrosis (CF) patients, carrying the CF-specific D508 mutated CFTR-allele. These profiles were compared with gene expression profiles from rectal suction specimens of non-CF subjects (control).
Project description:Genome editing using CRISPR-Cas systems is a promising avenue for the treatment of genetic diseases. However, cellular and humoral immunogenicity of genome editing tools, which originate from bacteria, complicates their clinical use. Here we report reduced immunogenicity (Red)(i)-variants of two clinically-relevant nucleases, SaCas9 and AsCas12a. Through MHC-associated peptide proteomics (MAPPs) analysis, we identified putative immunogenic epitopes on each nuclease. Then, we used computational modeling to rationally design these proteins to evade the immune response. SaCas9 and AsCas12a Redi variants were substantially less recognized by adaptive immune components, including reduced binding affinity to MHC molecules and attenuated generation of cytotoxic T cell responses, while maintaining wild-type levels of activity and specificity. In vivo editing of PCSK9 with SaCas9.Redi.1 was comparable in efficiency to wild-type SaCas9, but significantly reduced undesired immune responses. This demonstrates the utility of this approach in engineering proteins to evade immune detection.
2024-11-07 | PXD054579 | Pride
Project description:AsCas12a editing in endogenous gene
Project description:CRISPR-based gene perturbation enables unbiased investigations of single and combinatorial genotype-to-phenotype associations. In light of efforts to map combinatorial gene dependencies at scale, choosing an efficient and robust CRISPR-associated (Cas) nuclease is of utmost importance. Even though SpCas9 and AsCas12a are widely used for single, combinatorial, and orthogonal screenings, side-by-side comparisons remain sparse. Here, we systematically compared combinatorial SpCas9, AsCas12a, and CHyMErA in hTERT-immortalized retinal pigment epithelial cells and extracted performance-critical parameters for combinatorial and orthogonal CRISPR screens. Our analyses identified SpCas9 to be superior to enhanced and optimized AsCas12a, with CHyMErA being largely inactive in the tested conditions. Since AsCas12a contains RNA processing activity, we used arrayed dual-gRNAs to improve AsCas12a and CHyMErA applications. While this negatively influenced the effect size of combinatorial AsCas12a applications, it enhanced the performance of CHyMErA. This improved performance, however, was limited to AsCas12a dual-gRNAs, as SpCas9 gRNAs remained largely inactive. To avoid the use of hybrid gRNAs for orthogonal applications, we engineered the multiplex SpCas9-enAsCas12a system (multiSPAS) that avoids RNA processing for efficient orthogonal gene editing.
Project description:We examine cis-regulatory elements controlling expression of the cystic fibrosis transmembrane conductance regulator (CFTR) gene in ductal eptihelial cells from pancreas, bile duct and sweat gland. Mutations in CFTR are associated with the inherited disorder cystic fibrosis. We identify several novel sites in addition to multiple elements seen in in other epithelial cell types.
2025-08-20 | GSE283992 | GEO
Project description:Genome editing of F508del mutation in cystic fibrosis
Project description:The purpose of the study is to compare the transcriptomic profile of the airway epithelium generated from bronchial airway epithelial cells isolated from healthy donors (NCF) and patients with cystic fibrosis (CF). Cells were grown at the air-liquid interface for at least 2-months. CF is caused by mutations of the cystic fibrosis transmembrane conductance regulator (CFTR) gene. Only patients homozygous for the F508del mutation of the CFTR gene were considered. The reconstituted airway epithelium was mechanically wounded and allowed to repair with time. We considered four steps: 1) intact, non-wounded (NW) epithelium; 2) 24h hours post-wounding (pW); 3) time at which the wound is closed (WC); 4) two days post-wound closure (pWC). We also mimicked infection by exposing the cells to Pseudominas aeruginosa flagelin for NW and WC conditions.