Project description:Combination of stem cell-based approaches with gene-editing technologies represents an attractive strategy for studying human disease and developing therapies. However, gene-editing methodologies described to date for human cells suffer from technical limitations including limited target gene size, low targeting efficiency at transcriptionally inactive loci, and off-target genetic effects that could hamper broad clinical application. To address these limitations, and as a proof of principle, we focused on homologous recombination-based gene correction of multiple mutations on lamin A (LMNA), which are associated with various degenerative diseases. We show that helper-dependent adenoviral vectors (HDAdVs) provide a highly efficient and safe method for correcting mutations in large genomic regions in human induced pluripotent stem cells and can also be effective in adult human mesenchymal stem cells. This type of approach could be used to generate genotype-matched cell lines for disease modeling and drug discovery and potentially also in therapeutics.
Project description:We compared the epigenetic status of the mutant and disease-free iPSCs at the whole genome level. Whole epigenome profiling based on trimethylated H3K4 (H3K4me3) showed concordant epigenetic remodeling in the two corrected clones when compared with two mutant iPSC clones. Examination of the trimethylated H3K4 histone modification in Fanconi anemia patient iPSCs before and after gene correction
Project description:We compared the epigenetic status of the mutant and disease-free iPSCs at the whole genome level. Whole epigenome profiling based on trimethylated H3K4 (H3K4me3) showed concordant epigenetic remodeling in the two corrected clones when compared with two mutant iPSC clones. Examination of genome-wide gene expression in Fanconi anemia patient iPSCs before and after gene correction
Project description:Familial platelet disorder with predisposition to acute myeloid leukemia (FPD/AML) is an autosomal dominant disease of the hematopoietic system, which is caused by heterozygous mutations in RUNX1. FPD/AML patients have a bleeding disorder characterized by thrombocytopenia with reduced platelet numbers and functions, and a tendency to develop AML. Currently no suitable animal models exist for FPD/AML as Runx1+/- mice and zebrafish do not develop bleeding disorders or leukemia. Here we derived induced pluripotent stem cells (iPSCs) from two patients in a family with FPD/AML, and found that the FPD iPSCs display defects in megakaryocytic differentiation in vitro. We corrected the RUNX1 mutation in one FPD iPSC line through gene targeting, which led to normalization of megakaryopoiesis of the iPSCs in culture. Our results demonstrate successful in vitro modeling of FPD with patient-specific iPSCs and confirm that RUNX1 mutations are responsible for megakaryopoietic defects in FPD patients. Here, we derived iPSCs from two FPD/AML patients and demonstrated that these iPSCs have a megakaryopoietic defect in culture. Importantly we were able to rescue the megakaryopoietic defect by correcting the RUNX1 mutation with a gene targeting strategy enhanced by zinc finger nucleases (ZFNs). Three independent samples were obtained for each time point.
Project description:To ameliorate the cumbersome processes of reprogramming and subsequent gene-editing in vulnerable iPSCs, we have developed a greatly simplified one-step procedure, simultaneously introducing reprogramming and gene-editing components into human fibroblast cells. This not only serves to save time, labor, and costs, but opens up a new arena of research that is beyond the current application of gene-editing methodologies due to restrictive reprogramming concerns, inhibitory pluripotency maintenance requirements, and vulnerability of single-cell dissociated iPSCs. We generated iPSCs (mALK2-iPSCs) derived from Fibrodysplasia ossificans progressiva (FOP)-fibroblast cells carrying the ACVR1 p.R206H mutation and gene-corrected ALK2-iPSCs (cALK2-iPSCs). To identify gene-correction effects on global gene expression, gene expression profiling was measured in cALK2-iPSCs and mALK2-iPSCs, calibrated to WT-iPSCs with duplication.
Project description:Limb girdle muscular dystrophy type 2A (LGMD2A), caused by mutations in the Calpain 3 (CAPN3) gene, is an incurable autosomal recessive disorder that results in muscle wasting and loss of ambulation. To test the feasibility of an autologous induced pluripotent stem cell (iPSC)-based therapy for LGMD2A, here we applied CRISPR-Cas9-mediated genome editing to iPSCs from three LGMD2A patients to enable correction of mutations in the CAPN3 gene. Using a gene knockin approach, we genome edited iPSCs carrying three different CAPN3 mutations, and we demonstrated the rescue of CAPN3 protein in myotube derivatives in vitro. Transplantation of gene-corrected LGMD2A myogenic progenitors in a novel mouse model combining immunodeficiency and a lack of CAPN3 resulted in muscle engraftment and rescue of the CAPN3 mRNA. Thus, we provide here proof of concept for the integration of genome editing and iPSC technologies to develop a novel autologous cell therapy for LGMD2A.
Project description:We used a modified 5i/L/FA system to generate transgene-free naïve iPSCs directly from the fibroblasts of a patient suffering from β-thalassemia and further demonstrated efficient gene correction with a CRISPR/Cas9 system, which provides an improved strategy for personalized treatment of β-thalassemia.
Project description:Familial platelet disorder with predisposition to acute myeloid leukemia (FPD/AML) is an autosomal dominant disease of the hematopoietic system, which is caused by heterozygous mutations in RUNX1. FPD/AML patients have a bleeding disorder characterized by thrombocytopenia with reduced platelet numbers and functions, and a tendency to develop AML. Currently no suitable animal models exist for FPD/AML as Runx1+/- mice and zebrafish do not develop bleeding disorders or leukemia. Here we derived induced pluripotent stem cells (iPSCs) from two patients in a family with FPD/AML, and found that the FPD iPSCs display defects in megakaryocytic differentiation in vitro. We corrected the RUNX1 mutation in one FPD iPSC line through gene targeting, which led to normalization of megakaryopoiesis of the iPSCs in culture. Our results demonstrate successful in vitro modeling of FPD with patient-specific iPSCs and confirm that RUNX1 mutations are responsible for megakaryopoietic defects in FPD patients.
Project description:To elucidate the transcriptional and epigenetic alterations underlying the neurogenic defects of FA-NSCs, we conducted gene expression microarray analysis and global DNA methylation profiling. The gene expression pattern of gene-corrected NSCs (C-FA-NSCs) resembled that of control-NSCs but clustered distantly from FA-NSCs (Fig. 6F and Table S1). Hierarchical clustering based on DNA methylation levels in the promoter region (+/-1.5kb from TSS) of genes whose expression levels were rescued in C-FA-NSCs, placed C-FA-NSCs closer to control-NSCs and away from FA-NSCs (Fig. 6G), although this pattern was not seen at the whole genome level (Fig. S4C). This suggests that FANCA gene correction leads to specific methylation changes in a subset of promoters. Examination of the methylomes of NSCs derived from Fanconi Anemia iPSCs before and after gene correction by targeted bisulfite sequencing with padlock probes
Project description:Amyotrophic lateral sclerosis (ALS) is a complex neurodegenerative disease with cellular and molecular mechanisms yet to be fully described. Mutations in a number of genes including SOD1 and FUS are associated with familial ALS. Here we report the generation of induced pluripotent stem cells (iPSCs) from fibroblasts of familial ALS patients bearing SOD1 +/A272C and FUS +/G1566A mutations, respectively. We further generated gene corrected ALS iPSCs using CRISPR/Cas9 system. Genome-wide RNA sequencing (RNA-seq) analysis of motor neurons derived from SOD1 +/A272C and corrected iPSCs revealed 899 aberrant transcripts. Our work may shed light on discovery of early biomarkers and pathways dysregulated in ALS, as well as provide a basis for novel therapeutic strategies to treat ALS.