CRISPR Gene Editing on Human Embryos

Author(s):  
Fatemeh Sefid ◽  
Saedeh Khadempar ◽  
Roshanak Shamriz ◽  
Nooshin Amjadi

Background: With the recent development of CRISPR/Cas9 genome editing technology, the possibility to genetically influence the human germline (gametes and embryos) has become a separate technical possibility. As a powerful skill for genome engineering, the CRISPR/Cas9 system has been effectively applied to adjust the genomes of several species. The purpose of this review was to appraise the technology and build concepts for the launch of precise hereditary modifications in early human embryos.   Methods: We conducted a systematic review of the related literatures searched from PubMed, Google scholar, Web of Science up to June 30, 2017 and then we extracted the essential data. In this review, we present the brief history and basic mechanisms of the CRISPR/Cas9 system and significant challenges and advances in the field as a comprehensive practical guide to absorbed users of genome editing technologies. We introduce factors that influence CRISPR/Cas9 efficacy which must be addressed before effective in vivo human embryo therapy can be realized .in this review, we highlight the advancements that have been made using CRISPR/Cas9 in relation to Human Embryo.   Results and Conclusion: The possibility of CRISPR/Cas9 use in the context of human reproduction, to change embryos, germline cells, and pluripotent stem cells are studied created on the writers' expert belief. We discuss recent developments leading to the operation of Human Embryonic gene therapies in clinical trials and consider the predictions for future advances in this rapidly developing field.

Cells ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 467
Author(s):  
Min Hao ◽  
Zhaoguan Wang ◽  
Hongyan Qiao ◽  
Peng Yin ◽  
Jianjun Qiao ◽  
...  

As a key element of genome editing, donor DNA introduces the desired exogenous sequence while working with other crucial machinery such as CRISPR-Cas or recombinases. However, current methods for the delivery of donor DNA into cells are both inefficient and complicated. Here, we developed a new methodology that utilizes rolling circle replication and Cas9 mediated (RC-Cas-mediated) in vivo single strand DNA (ssDNA) synthesis. A single-gene rolling circle DNA replication system from Gram-negative bacteria was engineered to produce circular ssDNA from a Gram-positive parent plasmid at a designed sequence in Escherichia coli. Furthermore, it was demonstrated that the desired linear ssDNA fragment could be cut out using CRISPR-associated protein 9 (CRISPR-Cas9) nuclease and combined with lambda Red recombinase as donor for precise genome engineering. Various donor ssDNA fragments from hundreds to thousands of nucleotides in length were synthesized in E. coli cells, allowing successive genome editing in growing cells. We hope that this RC-Cas-mediated in vivo ssDNA on-site synthesis system will be widely adopted as a useful new tool for dynamic genome editing.


2019 ◽  
Vol 19 (3) ◽  
pp. 164-174 ◽  
Author(s):  
Jinyu Sun ◽  
Jianchu Wang ◽  
Donghui Zheng ◽  
Xiaorong Hu

Abstract Clustered regularly interspaced short palindromic repeats (CRISPR)-associated protein 9 (Cas9) is one of the most versatile and efficient gene editing technologies, which is derived from adaptive immune strategies for bacteria and archaea. With the remarkable development of programmable nuclease-based genome engineering these years, CRISPR-Cas9 system has developed quickly in recent 5 years and has been widely applied in countless areas, including genome editing, gene function investigation and gene therapy both in vitro and in vivo. In this paper, we briefly introduce the mechanisms of CRISPR-Cas9 tool in genome editing. More importantly, we review the recent therapeutic application of CRISPR-Cas9 in various diseases, including hematologic diseases, infectious diseases and malignant tumor. Finally, we discuss the current challenges and consider thoughtfully what advances are required in order to further develop the therapeutic application of CRISPR-Cas9 in the future.


2022 ◽  
Vol 3 ◽  
Author(s):  
Swati Bijlani ◽  
Ka Ming Pang ◽  
Venkatesh Sivanandam ◽  
Amanpreet Singh ◽  
Saswati Chatterjee

The replication-defective, non-pathogenic, nearly ubiquitous single-stranded adeno-associated viruses (AAVs) have gained importance since their discovery about 50 years ago. Their unique life cycle and virus-cell interactions have led to the development of recombinant AAVs as ideal genetic medicine tools that have evolved into effective commercialized gene therapies. A distinctive property of AAVs is their ability to edit the genome precisely. In contrast to all current genome editing platforms, AAV exclusively utilizes the high-fidelity homologous recombination (HR) pathway and does not require exogenous nucleases for prior cleavage of genomic DNA. Together, this leads to a highly precise editing outcome that preserves genomic integrity without incorporation of indel mutations or viral sequences at the target site while also obviating the possibility of off-target genotoxicity. The stem cell-derived AAV (AAVHSCs) were found to mediate precise and efficient HR with high on-target accuracy and at high efficiencies. AAVHSC editing occurs efficiently in post-mitotic cells and tissues in vivo. Additionally, AAV also has the advantage of an intrinsic delivery mechanism. Thus, this distinctive genome editing platform holds tremendous promise for the correction of disease-associated mutations without adding to the mutational burden. This review will focus on the unique properties of direct AAV-mediated genome editing and their potential mechanisms of action.


2018 ◽  
Author(s):  
Raed Ibraheim ◽  
Chun-Qing Song ◽  
Aamir Mir ◽  
Nadia Amrani ◽  
Wen Xue ◽  
...  

AbstractClustered, regularly interspaced, short palindromic repeats (CRISPR) and CRISPR-associated proteins (Cas) have recently opened a new avenue for gene therapy. Cas9 nuclease guided by a single-guide RNA (sgRNA) has been extensively used for genome editing. Currently, three Cas9 orthologs have been adapted for in vivo genome engineering applications: SpyCas9, SauCas9 and CjeCas9. However, additional in vivo editing platforms are needed, in part to enable a greater range of sequences to be accessed via viral vectors, especially those in which Cas9 and sgRNA are combined into a single vector genome. Here, we present an additional in vivo editing platform using Neisseria meningitidis Cas9 (NmeCas9). NmeCas9 is compact, edits with high accuracy, and possesses a distinct PAM, making it an excellent candidate for safe gene therapy applications. We find that NmeCas9 can be used to target the Pcsk9 and Hpd genes in mice. Using tail vein hydrodynamic-based delivery of NmeCas9 plasmid to target the Hpd gene, we successfully reprogrammed the tyrosine degradation pathway in Hereditary Tyrosinemia Type I mice. More importantly, we delivered NmeCas9 with its single-guide RNA in a single recombinant adeno-associated vector (rAAV) to target Pcsk9, resulting in lower cholesterol levels in mice. This all-in-one vector yielded >35% gene modification after two weeks of vector administration, with minimal off-target cleavage in vivo. Our findings indicate that NmeCas9 can facilitate future efforts to correct disease-causing mutations by expanding the targeting scope of RNA-guided nucleases.


2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Keishi Osakabe ◽  
Naoki Wada ◽  
Tomoko Miyaji ◽  
Emi Murakami ◽  
Kazuya Marui ◽  
...  

Abstract Genome editing in plants has advanced greatly by applying the clustered regularly interspaced short palindromic repeats (CRISPRs)-Cas system, especially CRISPR-Cas9. However, CRISPR type I—the most abundant CRISPR system in bacteria—has not been exploited for plant genome modification. In type I CRISPR-Cas systems, e.g., type I-E, Cas3 nucleases degrade the target DNA in mammals. Here, we present a type I-D (TiD) CRISPR-Cas genome editing system in plants. TiD lacks the Cas3 nuclease domain; instead, Cas10d is the functional nuclease in vivo. TiD was active in targeted mutagenesis of tomato genomic DNA. The mutations generated by TiD differed from those of CRISPR/Cas9; both bi-directional long-range deletions and short indels mutations were detected in tomato cells. Furthermore, TiD can be used to efficiently generate bi-allelic mutant plants in the first generation. These findings indicate that TiD is a unique CRISPR system that can be used for genome engineering in plants.


2021 ◽  
Vol 118 (22) ◽  
pp. e2004832117
Author(s):  
Gregorio Alanis-Lobato ◽  
Jasmin Zohren ◽  
Afshan McCarthy ◽  
Norah M. E. Fogarty ◽  
Nada Kubikova ◽  
...  

CRISPR-Cas9 genome editing is a promising technique for clinical applications, such as the correction of disease-associated alleles in somatic cells. The use of this approach has also been discussed in the context of heritable editing of the human germ line. However, studies assessing gene correction in early human embryos report low efficiency of mutation repair, high rates of mosaicism, and the possibility of unintended editing outcomes that may have pathologic consequences. We developed computational pipelines to assess single-cell genomics and transcriptomics datasets from OCT4 (POU5F1) CRISPR-Cas9–targeted and control human preimplantation embryos. This allowed us to evaluate on-target mutations that would be missed by more conventional genotyping techniques. We observed loss of heterozygosity in edited cells that spanned regions beyond the POU5F1 on-target locus, as well as segmental loss and gain of chromosome 6, on which the POU5F1 gene is located. Unintended genome editing outcomes were present in ∼16% of the human embryo cells analyzed and spanned 4–20 kb. Our observations are consistent with recent findings indicating complexity at on-target sites following CRISPR-Cas9 genome editing. Our work underscores the importance of further basic research to assess the safety of genome editing techniques in human embryos, which will inform debates about the potential clinical use of this technology.


2020 ◽  
Author(s):  
Zhanqi Dong ◽  
Qi Qin ◽  
Zhigang Hu ◽  
Xinling Zhang ◽  
Jianghao Miao ◽  
...  

AbstractCRISPR/Cas12a (Cpf1) is a single RNA-guided endonuclease that provides new opportunities for targeted genome engineering through the CRISPR/Cas9 system. Only AsCpf1 have been developed for insect genome editing, and the novel Cas12a orthologs nucleases and editing efficiency require more study in insect. We compared three Cas12a orthologs nucleases, AsCpf1, FnCpf1, and LbCpf1, for their editing efficiencies and antiviral abilities in vitro. The three Cpf1 efficiently edited the BmNPV genome and inhibited BmNPV replication in BmN-SWU1 cells. The antiviral ability of the FnCpf1 system was more efficient than the SpCas9 system after infection by BmNPV. We created FnCpf1×gIE1 and SpCas9×sgIE1 transgenic hybrid lines and evaluated the gene editing efficiency of different systems at the same target site. We improved the antiviral ability using the FnCpf1 system in transgenic silkworm. This study demonstrated use of the CRISPR/Cpf1 system to achieve high editing efficiencies in the silkworm, and illustrates the use of this technology for increasing disease resistance.Author SummaryGenome editing is a powerful tool that has been widely used in gene function, gene therapy, pest control, and disease-resistant engineering in most parts of pathogens research. Since the establishment of CRISPR/Cas9, powerful strategies for antiviral therapy of transgenic silkworm have emerged. Nevertheless, there is still room to expand the scope of genome editing tool for further application to improve antiviral research. Here, we demonstrate that three Cpf1 endonuclease can be used efficiency editing BmNPV genome in vitro and in vivo for the first time. More importantly, this Cpf1 system could improve the resistance of transgenic silkworms to BmNPV compare with Cas9 system, and no significant cocoons difference was observed between transgenic lines infected with BmNPV and control. These broaden the range of application of CRISPR for novel genome editing methods in silkworm and also enable sheds light on antiviral therapy.


2019 ◽  
Vol 3 (3) ◽  
pp. 327-334 ◽  
Author(s):  
Soragia Athina Gkazi

Abstract Recent advances in the era of genetic engineering have significantly improved our ability to make precise changes in the genomes of human cells. Throughout the years, clinical trials based on gene therapies have led to the cure of diseases such as X-linked severe combined immunodeficiency (SCID-X1), adenosine deaminase deficiency (ADA-SCID) and Wiskott–Aldrich syndrome. Despite the success gene therapy has had, there is still the risk of genotoxicity due to the potential oncogenesis introduced by utilising viral vectors. Research has focused on alternative strategies like genome editing without viral vectors as a means to reduce genotoxicity introduced by the viral vectors. Although there is an extensive use of RNA-guided genome editing via the clustered regularly interspaced short palindromic repeats (CRISPR) and associated protein-9 (Cas9) technology for biomedical research, its genome-wide target specificity and its genotoxic side effects remain controversial. There have been reports of on- and off-target effects created by CRISPR–Cas9 that can include small and large indels and inversions, highlighting the potential risk of insertional mutagenesis. In the last few years, a plethora of in silico, in vitro and in vivo genome-wide assays have been introduced with the sole purpose of profiling these effects. Here, we are going to discuss the genotoxic obstacles in gene therapies and give an up-to-date overview of methodologies for quantifying CRISPR–Cas9 effects.


Author(s):  
Amr A. Abdeen ◽  
Brian D. Cosgrove ◽  
Charles A. Gersbach ◽  
Krishanu Saha

The recent discovery and subsequent development of the clustered regularly interspaced short palindromic repeat (CRISPR)–CRISPR-associated (Cas) platform as a precise genome editing tool have transformed biomedicine. As these CRISPR-based tools have matured, multiple stages of the gene editing process and the bioengineering of human cells and tissues have advanced. Here, we highlight recent intersections in the development of biomaterials and genome editing technologies. These intersections include the delivery of macromolecules, where biomaterial platforms have been harnessed to enable nonviral delivery of genome engineering tools to cells and tissues in vivo. Further, engineering native-like biomaterial platforms for cell culture facilitates complex modeling of human development and disease when combined with genome engineering tools. Deeper integration of biomaterial platforms in these fields could play a significant role in enabling new breakthroughs in the application of gene editing for the treatment of human disease. Expected final online publication date for the Annual Review of Biomedical Engineering, Volume 23 is June 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.


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