scholarly journals Enhanced genome editing in human iPSCs with CRISPR-CAS9 by co-targeting ATP1a1

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9060
Author(s):  
Jui-Tung Liu ◽  
James L. Corbett ◽  
James A. Heslop ◽  
Stephen A. Duncan
Keyword(s):  
Genome Editing ◽  
Cardiac Glycoside ◽  
Disease Modeling ◽  
Fold Increase ◽  
Atpase Subunit ◽  
Homology Directed Repair ◽  
Human Ipscs ◽  
Repair Template ◽  
Low Efficiency ◽  
Induced Pluripotent

Genome editing in human induced pluripotent stem cells (iPSCs) provides the potential for disease modeling and cell therapy. By generating iPSCs with specific mutations, researchers can differentiate the modified cells to their lineage of interest for further investigation. However, the low efficiency of targeting in iPSCs has hampered the application of genome editing. In this study we used a CRISPR-Cas9 system that introduces a specific point substitution into the sequence of the Na+/K+-ATPase subunit ATP1A1. The introduced mutation confers resistance to cardiac glycosides, which can then be used to select successfully targeted cells. Using this system, we introduced different formats of donor DNA for homology-directed repair (HDR), including single-strand DNAs, double-strand DNAs, and plasmid donors. We achieved a 35-fold increase in HDR when using plasmid donor with a 400 bp repair template. We further co-targeted ATP1A1 and a second locus of interest to determine the enrichment of mutagenesis after cardiac glycoside selection. Through this approach, INDEL rate was increased after cardiac glycoside treatment, while HDR enrichment was only observed at certain loci. Collectively, these results suggest that a plasmid donor with a 400 bp repair template is an optimal donor DNA for targeted substitution and co-targeting ATP1A1 with the second locus enriches for mutagenesis events through cardiac glycoside selection in human iPSCs.

scholarly journals Highly efficient chondrogenic differentiation of human iPSCs and purification via a reporter allele generated by CRISPR-Cas9 genome editing

2018 ◽  
Author(s):  
Shaunak S. Adkar ◽  
Chia-Lung Wu ◽  
Vincent P. Willard ◽  
Amanda Dicks ◽  
Adarsh Ettyreddy ◽  
...  
Keyword(s):  
Genome Editing ◽  
Disease Modeling ◽  
Cell Types ◽  
Patient Specific ◽  
Cell Fates ◽  
Highly Efficient ◽  
Differentiation Protocol ◽  
Human Ipscs ◽  
Specific Tissue ◽  
Induced Pluripotent

SummaryThe differentiation of human induced pluripotent stem cells (hiPSCs) to prescribed cell fates enables the engineering of patient-specific tissue types, such as hyaline cartilage, for applications in regenerative medicine, disease modeling, and drug screening. In many cases, however, these differentiation approaches are poorly controlled and generate heterogeneous cell populations. Here we demonstrate robust cartilaginous matrix production in three unique hiPSC lines using a highly efficient and reproducible differentiation protocol. To purify chondroprogenitors produced by this protocol, we engineered a COL2A1-GFP knock-in reporter hiPSC line by CRISPR-Cas9 genome editing. Purified chondroprogenitors demonstrated an improved chondrogenic capacity compared to unselected populations. The ability to enrich for chrondroprogenitors and generate homogenous matrix without contaminating cell types will be essential for regenerative and disease modeling applications.

scholarly journals Use of single guided Cas9 nickase to facilitate precise and efficient genome editing in human iPSCs

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Pan P. Li ◽  
Russell L. Margolis
Keyword(s):  
Genome Editing ◽  
Disease Modeling ◽  
Neurodegenerative Disorder ◽  
Cag Repeat ◽  
Spinocerebellar Ataxia Type ◽  
End Joining ◽  
Human Ipscs ◽  
Non Homologous End Joining ◽  
Transient Overexpression ◽  
Donor Template

AbstractCas9 nucleases permit rapid and efficient generation of gene-edited cell lines. However, in typical protocols, mutations are intentionally introduced into the donor template to avoid the cleavage of donor template or re-cleavage of the successfully edited allele, compromising the fidelity of the isogenic lines generated. In addition, the double-stranded breaks (DSBs) used for editing can introduce undesirable “on-target” indels within the second allele of successfully modified cells via non-homologous end joining (NHEJ). To address these problems, we present an optimized protocol for precise genome editing in human iPSCs that employs (1) single guided Cas9 nickase to generate single-stranded breaks (SSBs), (2) transient overexpression of BCL-XL to enhance survival post electroporation, and (3) the PiggyBac transposon system for seamless removal of dual selection markers. We have used this method to modify the length of the CAG repeat contained in exon 7 of PPP2R2B. When longer than 43 triplets, this repeat causes the neurodegenerative disorder spinocerebellar ataxia type 12 (SCA12); our goal was to seamlessly introduce the SCA12 mutation into a human control iPSC line. With our protocol, ~ 15% of iPSC clones selected had the desired gene editing without “on target” indels or off-target changes, and without the deliberate introduction of mutations via the donor template. This method will allow for the precise and efficient editing of human iPSCs for disease modeling and other purposes.

Stem Cells Applications in Therapeutics and Site-Specific Genome Editing Through CRISPR Cas9 System

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Javed M ◽  
◽  
Khan A ◽  
Mukheed M ◽  
◽  
...  
Keyword(s):  
Stem Cells ◽  
Genome Editing ◽  
Pluripotent Stem Cells ◽  
Disease Modeling ◽  
Cell Types ◽  
Multipotent Stem Cells ◽  
Site Specific ◽  
Regenerative Medicines ◽  
Induced Pluripotent ◽  
Adult Cells

Stem cells ae immature cells that have ability to differentiate into all specific and mature cells in body. The two main characteristics of stem cells are selfrenewable and ability to differentiate into all mature, functional and adult cells types. There are the two major classes a) pluripotent stem cells which have potential to differentiate in all adult cell and b) multipotent stem cells which have capacity to differentiate into many adult cells but not in all cell types. Due to the self-renewable ability stem cells are use in therapeutics, tissue regeneration, disease modeling and regenerative medicines and to treat cardiovascular diseases, neural disorders such as Parkinson’s disease and most importantly to treat carcinomas. The human induced pluripotent stem cells provide a great platform to study and treatment of human diseases because these are able to differentiate into many functional and specialized adult cells of body. The genome editing tools such as CRISPR Cas9 system and TALENs are used to generate multiple DNA variants in hPSCs by inducing site specific mutations, frame shift mutation and deletion. In present days CRISPR Cas9 is more efficient and frequent method for genome editing which is derived from bacterial cell.

scholarly journals Francisella novicida Cas9 interrogates genomic DNA with very high specificity and can be used for mammalian genome editing

2019 ◽  
Vol 116 (42) ◽  
pp. 20959-20968 ◽  
Author(s):  
Sundaram Acharya ◽  
Arpit Mishra ◽  
Deepanjan Paul ◽  
Asgar Hussain Ansari ◽  
Mohd. Azhar ◽  
...  
Keyword(s):  
Genome Editing ◽  
Genetic Disorders ◽  
High Specificity ◽  
Francisella Novicida ◽  
Guide Rna ◽  
Homology Directed Repair ◽  
Multiple Loci ◽  
Specificity Of Binding ◽  
Induced Pluripotent ◽  
Very High

Genome editing using the CRISPR/Cas9 system has been used to make precise heritable changes in the DNA of organisms. Although the widely used Streptococcus pyogenes Cas9 (SpCas9) and its engineered variants have been efficiently harnessed for numerous gene-editing applications across different platforms, concerns remain regarding their putative off-targeting at multiple loci across the genome. Here we report that Francisella novicida Cas9 (FnCas9) shows a very high specificity of binding to its intended targets and negligible binding to off-target loci. The specificity is determined by its minimal binding affinity with DNA when mismatches to the target single-guide RNA (sgRNA) are present in the sgRNA:DNA heteroduplex. FnCas9 produces staggered cleavage, higher homology-directed repair rates, and very low nonspecific genome editing compared to SpCas9. We demonstrate FnCas9-mediated correction of the sickle cell mutation in patient-derived induced pluripotent stem cells and propose that it can be used for precise therapeutic genome editing for a wide variety of genetic disorders.

scholarly journals Enhancement of homology-directed repair with chromatin donor templates in cells

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Grisel Cruz-Becerra ◽  
James T Kadonaga
Keyword(s):  
Genome Editing ◽  
Dna Fragments ◽  
Natural Form ◽  
Naked Dna ◽  
Homology Directed Repair ◽  
Coding Regions ◽  
Wide Range ◽  
Low Efficiency ◽  
Donor Template ◽  
In Cells

A key challenge in precise genome editing is the low efficiency of homology-directed repair (HDR). Here we describe a strategy for increasing the efficiency of HDR in cells by using a chromatin donor template instead of a naked DNA donor template. The use of chromatin, which is the natural form of DNA in the nucleus, increases the frequency of HDR-edited clones as well as homozygous editing. In addition, transfection of chromatin results in negligible cytotoxicity. These findings suggest that a chromatin donor template should be useful for a wide range of HDR applications such as the precise insertion or replacement of DNA fragments that contain the coding regions of genes.

scholarly journals The Cutting Edge of Disease Modeling: Synergy of Induced Pluripotent Stem Cell Technology and Genetically Encoded Biosensors

Biomedicines ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 960
Author(s):  
Kamila R. Valetdinova ◽  
Tuyana B. Malankhanova ◽  
Suren M. Zakian ◽  
Sergey P. Medvedev
Keyword(s):  
Drug Screening ◽  
Disease Modeling ◽  
Tissue Type ◽  
Live Cells ◽  
Cell Models ◽  
Drug Bioavailability ◽  
Biosensor Technology ◽  
Human Ipscs ◽  
Monogenic Diseases ◽  
Induced Pluripotent

The development of cell models of human diseases based on induced pluripotent stem cells (iPSCs) and a cell therapy approach based on differentiated iPSC derivatives has provided a powerful stimulus in modern biomedical research development. Moreover, it led to the creation of personalized regenerative medicine. Due to this, in the last decade, the pathological mechanisms of many monogenic diseases at the cell level have been revealed, and clinical trials of various cell products derived from iPSCs have begun. However, it is necessary to reach a qualitatively new level of research with cell models of diseases based on iPSCs for more efficient searching and testing of drugs. Biosensor technology has a great application prospect together with iPSCs. Biosensors enable researchers to monitor ions, molecules, enzyme activities, and channel conformation in live cells and use them in live imaging and drug screening. These probes facilitate the measurement of steady-state concentrations or activity levels and the observation and quantification of in vivo flux and kinetics. Real-time monitoring of drug action in a specific cellular compartment, organ, or tissue type; the ability to screen at the single-cell resolution; and the elimination of the false-positive results caused by low drug bioavailability that is not detected by in vitro testing methods are a few of the benefits of using biosensors in drug screening. Here, we discuss the possibilities of using biosensor technology in combination with cell models based on human iPSCs and gene editing systems. Furthermore, we focus on the current achievements and problems of using these methods.

scholarly journals Precision genome editing in the CRISPR era

2017 ◽  
Vol 95 (2) ◽  
pp. 187-201 ◽  
Author(s):  
Jayme Salsman ◽  
Graham Dellaire
Keyword(s):  
Gene Therapy ◽  
Genome Editing ◽  
Point Mutations ◽  
Dna Double Strand Breaks ◽  
End Joining ◽  
Genetic Changes ◽  
New Era ◽  
Homology Directed Repair ◽  
Repair Template ◽  
Non Homologous End Joining

With the introduction of precision genome editing using CRISPR–Cas9 technology, we have entered a new era of genetic engineering and gene therapy. With RNA-guided endonucleases, such as Cas9, it is possible to engineer DNA double strand breaks (DSB) at specific genomic loci. DSB repair by the error-prone non-homologous end-joining (NHEJ) pathway can disrupt a target gene by generating insertions and deletions. Alternatively, Cas9-mediated DSBs can be repaired by homology-directed repair (HDR) using an homologous DNA repair template, thus allowing precise gene editing by incorporating genetic changes into the repair template. HDR can introduce gene sequences for protein epitope tags, delete genes, make point mutations, or alter enhancer and promoter activities. In anticipation of adapting this technology for gene therapy in human somatic cells, much focus has been placed on increasing the fidelity of CRISPR–Cas9 and increasing HDR efficiency to improve precision genome editing. In this review, we will discuss applications of CRISPR technology for gene inactivation and genome editing with a focus on approaches to enhancing CRISPR–Cas9-mediated HDR for the generation of cell and animal models, and conclude with a discussion of recent advances and challenges towards the application of this technology for gene therapy in humans.

scholarly journals 5' modifications improve potency and efficacy of DNA donors for precision genome editing

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Krishna S Ghanta ◽  
Zexiang Chen ◽  
Aamir Mir ◽  
Gregoriy A Dokshin ◽  
Pranathi M Krishnamurthy ◽  
...  
Keyword(s):  
Dna Repair ◽  
Genome Editing ◽  
Triethylene Glycol ◽  
Great Promise ◽  
Precise Form ◽  
Homology Directed Repair ◽  
Genomic Location ◽  
Cultured Human Cells ◽  
Repair Template ◽  
Template Dna

Nuclease-directed genome editing is a powerful tool for investigating physiology and has great promise as a therapeutic approach to correct mutations that cause disease. In its most precise form, genome editing can use cellular homology-directed repair (HDR) pathways to insert information from an exogenously supplied DNA repair template (donor) directly into a targeted genomic location. Unfortunately, particularly for long insertions, toxicity and delivery considerations associated with repair template DNA can limit HDR efficacy. Here, we explore chemical modifications to both double-stranded and single-stranded DNA-repair templates. We describe 5′-terminal modifications, including in its simplest form the incorporation of triethylene glycol (TEG) moieties, that consistently increase the frequency of precision editing in the germlines of three animal models (Caenorhabditis elegans, zebrafish, mice) and in cultured human cells.

scholarly journals Retron Editing for Precise Genome Editing without Exogenous Donor DNA in Human Cells

2021 ◽  
Author(s):  
Xiangfeng Kong ◽  
Zikang Wang ◽  
Yingsi Zhou ◽  
Xing Wang ◽  
Linyu Shi ◽  
...  
Keyword(s):  
Genome Editing ◽  
Ex Vivo ◽  
Human Cells ◽  
Exogenous Dna ◽  
Guide Rna ◽  
Homology Directed Repair ◽  
Non Coding Rna ◽  
Bacterial Genetic ◽  
Low Efficiency

CRISPR-Cas9 mediated seamless genome editing can be achieved by incorporating donor DNA into the CRISPR-Cas9 target loci via homology-directed repair (HDR), albeit with relative low efficiency due to the inefficient delivery of exogenous DNA. Retrons are bacterial genetic element composed of a non-coding RNA (ncRNA) and reverse transcriptase (RT). Retrons coupled with CRISPR-Cas9 have been shown to enhance precise genome editing via HDR in yeast through fusing guide RNA (gRNA) to the 3′ end of retron ncRNA, producing multicopy single-stranded DNA (msDNA) covalently tethered to gRNA. Here, we further engineered retrons by fusing Cas9 with E.coli RT from different clades and joining gRNA at the 5′ end of retron ncRNA, and found that retron editing can achieve precise genome editing efficiently in human cells. By co- expression of Cas9-RT fusions and retron-ncRNA gRNA (rgRNA) in HEK293T cells, we demonstrated the rates of retron editing at endogenous genomic loci was up to 10 %. We expect our retron editing system could aid in advancing the ex vivo and in vivo therapeutic applications of retron.

Stem Cells Applications in Therapeutics and Site-Specific Genome Editing Through CRISPR Cas9 System

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Mukheed M ◽  
◽  
Kha A ◽  
Keyword(s):  
Stem Cells ◽  
Genome Editing ◽  
Pluripotent Stem Cells ◽  
Disease Modeling ◽  
Cell Types ◽  
Multipotent Stem Cells ◽  
Site Specific ◽  
Regenerative Medicines ◽  
Induced Pluripotent ◽  
Adult Cells

Stem cells are immature cells that have ability to differentiate into all specific and mature cells in body. The two main characteristics of stem cells are selfrenewable and ability to differentiate into all mature, functional and adult cells types. There are the two major classes a) pluripotent stem cells which have potential to differentiate in all adult cell and b) multipotent stem cells which have capacity to differentiate into many adult cells but not in all cell types. Due to the self-renewable ability stem cells are used in therapeutics, tissue regeneration, disease modeling, regenerative medicines and to treat cardiovascular diseases, neural disorders such as Parkinson’s disease and most importantly to treat carcinomas. The human induced pluripotent stem cells provide a great platform to study and treatment of human diseases because these are able to differentiate into many functional and specialized adult cells of body. The genome editing tools such as CRISPR Cas9 system and TALENs are used to generate multiple DNA variants in hPSCs by inducing site specific mutations, frame shift mutation and deletion. In present days CRISPR Cas9 is more efficient and frequent method for genome editing which is derived from bacterial cell.

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