Research on the Ethical Supervision of Human Gene Editing Technology: Based on the Perspective of Game Theory / 中国医学伦理学

In view of the current norms and demands of human gene editing technology at home and abroad, the paper explained that the regulatory difficulties faced by human gene editing technology were due to the conflict between economic interests and moral bottom line by constructing a game model in a hypothetical way. On this basis, the ideas of the supervision mode of human gene editing technology were put forward: establish unified international standards based on the country as the main body, enact more stringent and effective laws, to jointly deal with the behavior of genetic manipulation of human gametes, zygotes and embryos for the purpose of reproductive, and ensure the normalization and legalization of gene editing technology to avoid technology abuse.

Advances in corneal stromal regeneration and repair / 国际眼科杂志(Guoji Yanke Zazhi)

Corneal stroma is a significant part of the cornea and plays a significant role in the eye's refractive system. Although corneal transplantation is now the most effective treatment for corneal stromal disease, its advancement has been constrained by a shortage of donors, the need for prolonged immunosuppressive medicine to prevent rejection, and low graft survival rates. An alternate strategy is to use the corneal stroma's natural capacity for regeneration to create the ideal conditions for the collagenous extracellular matrix of the stroma to self-renew. However, it is challenging to replicate the intricate ultrastructure of the corneal stroma in vitro. Regenerative medicine has so been used to address these issues. These approaches refer to numerous disciplines, including stem cell-induced differentiation, tissue engineering and gene editing. This article provides potential directions for the future clinical applications of corneal stromal regeneration and repair while summarizing pertinent techniques, research progress, and issues.

Logic-gated tumor-microenvironment nanoamplifier enables targeted delivery of CRISPR/Cas9 for multimodal cancer therapy

Recent innovations in nanomaterials inspire abundant novel tumor-targeting CRISPR-based gene therapies. However, the therapeutic efficiency of traditional targeted nanotherapeutic strategies is limited by that the biomarkers vary in a spatiotemporal-dependent manner with tumor progression. Here, we propose a self-amplifying logic-gated gene editing strategy for gene/H2O2-mediated/starvation multimodal cancer therapy. In this approach, a hypoxia-degradable covalent-organic framework (COF) is synthesized to coat a-ZIF-8 in which glucose oxidase (GOx) and CRISPR system are packaged. To intensify intracellular redox dyshomeostasis, DNAzymes which can cleave catalase mRNA are loaded as well. When the nanosystem gets into the tumor, the weakly acidic and hypoxic microenvironment degrades the ZIF-8@COF to activate GOx, which amplifies intracellular H+ and hypoxia, accelerating the nanocarrier degradation to guarantee available CRISPR plasmid and GOx release in target cells. These tandem reactions deplete glucose and oxygen, leading to logic-gated-triggered gene editing as well as synergistic gene/H2O2-mediated/starvation therapy. Overall, this approach highlights the biocomputing-based CRISPR delivery and underscores the great potential of precise cancer therapy.

Gene therapy strategies and prospects for neurofibromatosis type 1 / 中国修复重建外科杂志

OBJECTIVE@#To summarize the gene therapy strategies for neurofibromatosis type 1 (NF1) and related research progress.@*METHODS@#The recent literature on gene therapy for NF1 at home and abroad was reviewed. The structure and function of the NF1 gene and its mutations were analyzed, and the current status as well as future prospects of the transgenic therapy and gene editing strategies were summarized.@*RESULTS@#NF1 is an autosomal dominantly inherited tumor predisposition syndrome caused by mutations in the NF1 tumor suppressor gene, which impair the function of the neurofibromin and lead to the disease. It has complex clinical manifestations and is not yet curable. Gene therapy strategies for NF1 are still in the research and development stage. Existing studies on the transgenic therapy for NF1 have mainly focused on the construction and expression of the GTPase-activating protein-related domain in cells that lack of functional neurofibromin, confirming the feasibility of the transgenic therapy for NF1. Future research may focus on split adeno-associated virus (AAV) gene delivery, oversized AAV gene delivery, and the development of new vectors for targeted delivery of full-length NF1 cDNA. In addition, the gene editing tools of the new generation have great potential to treat monogenic genetic diseases such as NF1, but need to be further validated in terms of efficiency and safety.@*CONCLUSION@#Gene therapy, including both the transgenic therapy and gene editing, is expected to become an important new therapeutic approach for NF1 patients.

CRISPR/Cas9 genome editing approaches for psychiatric research

Currently, genome editing technologies, such as clustered regularly interspaced short palindromic repeats (CRISPR/Cas9), are predominantly used to model genetic diseases. This genome editing system can correct point or frameshift mutations in risk genes. Here, we analyze and discuss the advantages of genome editing, its current applications, and the feasibility of the CRISPR/Cas9 system in research on psychiatric disorders. These disorders produce cognitive and behavioral alterations and their etiology is associated with polygenetic and environmental factors. CRISPR/Cas9 may reveal the biological mechanisms of psychiatric disorders at a basic research level, translating a suitable clinical approach for use in the diagnosis and treatment of psychiatric disorders. Genetic diagnosis and treatment for these disorders have not yet been fully established in psychiatry due to the limited understanding of their heterogeneity and polygenicity. We discuss the challenges and ethical issues in using CRISPR/Cas9 as a tool for diagnosis or gene therapy.

Editing the Human Genome with CRISPR/Cas: A Review of its Molecular Basis, Current Clinical Applications, and Bioethical Implications

ABSTRACT CRISPR/Cas genes evolved in prokaryotic organisms as a mechanism of defense designed to identify and destroy genetic material from threatening viruses. A breakthrough discovery is that CRISPR/Cas system can be used in eukaryotic cells to edit almost any desired gene. This comprehensive review addresses the most relevant work in the CRISPR/Cas field, including its history, molecular biology, gene editing capability, ongoing clinical trials, and bioethics. Although the science involved is complex, we intended to describe it in a concise manner that could be of interest to diverse readers, including anyone dedicated to the treatment of patients who could potentially benefit from gene editing, molecular biologists, and bioethicists. CRISPR/Cas has the potential to correct inherited diseases caused by single point mutations, to knock-in the promoter of a gene whose expression is highly desirable or knockout the gene coding for a deleterious protein. CRISPR/Cas technique can also be used to edit ex vivo immune cells and reinsert them in patients, improving their efficiency in attacking malignant cells, limiting the infectious potential of viruses or modulating xenotransplant rejection. Very important bioethical considerations on this topic include the need to internationally regulate its use by ad hoc expert committees and to limit its use until safety and bioethical issues are satisfactorily resolved.

Research progress on clustered regularly interspaced short palindromic repeats-associated 9 system for the treatment of HSV / 中华检验医学杂志

Herpes simplex virus (HSV) is a double-stranded DNA enveloped virus that causes severe effects on the human body by infecting the skin and nerve tissues. Because of latency and reactivation, the rapid detection and eradication of HSV are great challenges for clinical treatments. In recent years, clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated 9 (Cas9) system has developed rapidly in the field of gene editing and detection due to its simple design and high targeting efficiency.

Recent advances in preclinical research of renal xenotransplantation and selection of potential recipients in the future / 中华器官移植杂志

After continuous efforts from generations of transplant surgeons, kidney transplantation (KT) has become an optimal treatment for end-stage renal disease.However, an imbalance between supply and demand of organs has always restricted the development of KT.For this clinical dilemma, xenotransplantation is expected to become one practical alternative for alleviating organ shortage.This review summarized recent literature reports of kidney xenotransplantation and the latest cases of pig-to-human kidney and heart transplantations.Also clinical transformations and applications of kidney xenotransplantation were discussed.

Construction of human TCRP1 gene knockout chronic myeloid leukemia K562 cell line using CRISPR/Cas9 technology and its biological function detection / 中国医师杂志

Objective:To select human chronic myeloid leukemia (CML) cell line K562 as the experimental object, and use lentivirus mediated CRISPR/Cas9 gene editing technology to construct a stable CML cell line K562/TCRP1-KO that knocks out the tongue cancer resistance related protein 1 (TCRP1) gene; and through functional tests such as cell proliferation, apoptosis, and drug sensitivity, compare the phenotypic differences between K562/TCRP1-KO and control cells (K562/cas9-CTL), and preliminarily explore the possible mechanism of TCRP1 gene involvement in the pathogenesis of CML.Methods:The small guide RNA (sgRNA) targeting TCRP1 was designed at a specific location. After annealing, the oligonucleotide fragments were recombined with the linearized Cas9 expression vector, and the lentivirus packaging system was transfected into 293T cells. The purified virus was collected and infected with K562 cells. Positive polyclons were screened for puromycin pressure, and monoclonal K562/TCRP1-KO was further screened by limited dilution method. Stable cell lines were successfully knocked out by sanger sequencing and Western blot detection; Simultaneously, K562 cells transfected with lentiCRISPR vector were constructed as control cell lines (K562/cas9-CTL); Using cell counting method, cell counting kit 8 (CCK8) method, imatinib (IM) gradient dilution method, and flow cytometry cell proliferation, drug sensitivity, and apoptosis analysis were performed on K562/TCRP1-KO and K562/cas9-CTL, respectively.Results:The sgRNA-Cas9 recombinant plasmid vector for TCRP1 knockout was successfully constructed, and after transfection into 293T cells, TCRP1 knockout monoclonal cell lines were successfully screened using limited dilution method. Compared with K562/cas9-CTL cells, the proliferation ability of K562/TCRP1-KO cells was significantly reduced, IM drug sensitivity was significantly enhanced, and the process of cell apoptosis was significantly accelerated (all P<0.05). Conclusions:A CML cell line with TCRP1 knockout was successfully constructed using CRISPR/Cas9. TCRP1 may act as a cancer related gene to affect the proliferation, IM resistance, and apoptosis process of CML cells.

Application of CRISPR/Cas9 genome editing technology in hereditary retinal diseases / 中华实验眼科杂志

Several mutant genes for inherited retinal diseases have been identified, but effective treatments are still lacking.The clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein (Cas) system can edit human genomic DNA by nonhomologous end joining or homology-directed repair, offering more possibilities for the treatment of hereditary retinal diseases.CRISPR/Cas9 not only can genetically correct patient-derived induced pluripotent stem cells (iPSCs) to observe their differentiation into retinal cells thereby, thereby exploring the pathogenesis of the disease and implementing cell therapy, but can also be delivered to the body via vectors and directly act on target cells to achieve in vivo gene editing.CRISPR/Cas9 gene editing technology in hereditary retinal diseases has been mainly used in retinitis pigmentosa, hereditary X-linked juvenile retinoschisis, and Leber congenital amaurosis 10, of which the in vitro application of CRISPR/Cas9 for Leber congenital amaurosis 10 has entered the clinical trial stage.In this paper, we reviewed the mechanism and key advances of CRISPR/Cas9 and provided an overview of gene editing in IRDs.

Research progress in the application of CRISPR/Cas9 technology in the treatment of cervical cancer / 国际生物医学工程杂志

Cervical cancer is the fourth-ranked malignant tumor of female cancer in the world, and it seriously threatens women’s health. The main treatment options for patients with cervical cancer are surgery or concurrent chemoradiotherapy. With the development of medical research, researchers are committed to exploring more effective and specific treatment options in order to increase the treatment options for cervical cancer and improve the treatment effect. Clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated protein 9 (Cas9) technology is a method in which the Cas9 protein uses guide RNA (gRNA) to target the target gene and achieve precise editing of the target gene. At present, CRISPR/Cas9 technology has become a promising and powerful gene editing tool, a new and effective targeted therapy that has been applied in the treatment of various tumors. The research progress of CRISPR/Cas9 technology in the treatment of cervical cancer is mainly reviewed in terms of action targets, combination therapy strategies, and related drug resistance gene screening in order to provide new strategies for the treatment of cervical cancer.

Rapid detection and genotyping of SARS-CoV-2 Omicron BA.4/5 variants using a RT-PCR and CRISPR-Cas12a-based assay / 南方医科大学学报

OBJECTIVE@#To establish a rapid detection and genotyping method for SARS-CoV-2 Omicron BA.4/5 variants using CRISPPR-Cas12a gene editing technology.@*METHODS@#We combined reverse transcription-polymerase chain reaction (RT-PCR) and CRISPR gene editing technology and designed a specific CRISPPR RNA (crRNA) with suboptimal protospacer adjacent motifs (PAM) for rapid detection and genotyping of SARS- CoV-2 Omicron BA.4/5 variants. The performance of this RT- PCR/ CRISPPR-Cas12a assay was evaluated using 43 clinical samples of patients infected by wild-type SARS-CoV-2 and the Alpha, Beta, Delta, Omicron BA. 1 and BA. 4/5 variants and 20 SARS- CoV- 2-negative clinical samples infected with 11 respiratory pathogens. With Sanger sequencing method as the gold standard, the specificity, sensitivity, concordance (Kappa) and area under the ROC curve (AUC) of RT-PCR/CRISPPR-Cas12a assay were calculated.@*RESULTS@#This assay was capable of rapid and specific detection of SARS- CoV-2 Omicron BA.4/5 variant within 30 min with the lowest detection limit of 10 copies/μL, and no cross-reaction was observed in SARS-CoV-2-negative clinical samples infected with 11 common respiratory pathogens. The two Omicron BA.4/5 specific crRNAs (crRNA-1 and crRNA-2) allowed the assay to accurately distinguish Omicron BA.4/5 from BA.1 sublineage and other major SARS-CoV-2 variants of concern. For detection of SARS-CoV-2 Omicron BA.4/5 variants, the sensitivity of the established assay using crRNA-1 and crRNA-2 was 97.83% and 100% with specificity of 100% and AUC of 0.998 and 1.000, respectively, and their concordance rate with Sanger sequencing method was 92.83% and 96.41%, respectively.@*CONCLUSION@#By combining RT-PCR and CRISPPR-Cas12a gene editing technology, we successfully developed a new method for rapid detection and identification of SARS-CoV-2 Omicron BA.4/5 variants with a high sensitivity, specificity and reproducibility, which allows rapid detection and genotyping of SARS- CoV-2 variants and monitoring of the emerging variants and their dissemination.

Engineering and application of Komagataella phaffii as a cell factory / 生物工程学报

Nowadays, engineered Komagataella phaffii plays an important role in the biosynthesis of small molecule metabolites and protein products, showing great potential and value in industrial productions. With the development and application of new editing tools such as CRISPR/Cas9, it has become possible to engineer K. phaffii into a cell factory with high polygenic efficiency. Here, the genetic manipulation techniques and objectives for engineering K. phaffii are first summarized. Secondly, the applications of engineered K. phaffii as a cell factory are introduced. Meanwhile, the advantages as well as disadvantages of using engineered K. phaffii as a cell factory are discussed and future engineering directions are prospected. This review aims to provide a reference for further engineering K. phaffii cell factory, which is supposed to facilitate its application in bioindustry.

A novel CRISPR/Cas9-hLacI donor adapting system for dsDNA-templated gene editing / 生物工程学报

During the gene editing process mediated by CRISPR/Cas9, precise genome editing and gene knock-in can be achieved by the homologous recombination of double-stranded DNA (dsDNA) donor template. However, the low-efficiency of homologous recombination in eukaryotic cells hampers the development and application of this gene editing strategy. Here, we developed a novel CRISPR/Cas9-hLacI donor adapting system (DAS) to enhance the dsDNA-templated gene editing, taking the advantage of the specific binding of the LacI repressor protein and the LacO operator sequence derived for the Escherichia coli lactose operon. The codon-humanized LacI gene was fused as an adaptor to the Streptococcus pyogenes Cas9 (SpCas9) and Staphylococcus lugdunensis Cas9 (SlugCas9-HF) genes, and the LacO operator sequence was used as the aptamer and linked to the dsDNA donor template by PCR. The Cas9 nuclease activity after the fusion and the homology-directed repair (HDR) efficiency of the LacO-linked dsDNA template were firstly examined using surrogate reporter assays with the corresponding reporter vectors. The CRISPR/Cas9-hLacI DASs mediated genome precise editing were further checked, and we achieved a high efficiency up to 30.5% of precise editing at the VEGFA locus in HEK293T cells by using the CRISPR/SlugCas9-hLacI DAS. In summary, we developed a novel CRISPR/Cas9-hLacI DAS for dsDNA-templated gene editing, which enriches the CRISPR/Cas9-derived gene editing techniques and provides a novel tool for animal molecular design breeding researches.

Application of single base editing technique in pig genetic improvement: a review / 生物工程学报

Traditional pig breeding has a long cycle and high cost, and there is an urgent need to use new technologies to revitalize the pig breeding industry. The recently emerged CRISPR/Cas9 genome editing technique shows great potential in pig genetic improvement, and has since become a research hotspot. Base editor is a new base editing technology developed based on the CRISPR/Cas9 system, which can achieve targeted mutation of a single base. CRISPR/Cas9 technology is easy to operate and simple to design, but it can lead to DNA double strand breaks, unstable gene structures, and random insertion and deletion of genes, which greatly restricts the application of this technique. Different from CRISPR/Cas9 technique, the single base editing technique does not produce double strand breaks. Therefore, it has higher accuracy and safety for genome editing, and is expected to advance the pig genetic breeding applications. This review summarized the working principle and shortcomings of CRISPR/Cas9 technique, the development and advantages of single base editing, the principles and application characteristics of different base editors and their applications in pig genetic improvement, with the aim to facilitate genome editing-assisted genetic breeding of pig.

Destruction of Being "Lifted": A Study on Klara and the Sun from the Perspective of Bioethics / 中国医学伦理学

Klara and the Sun is the first work published by Kazuo Ishiguro after he won the Nobel Prize for Literature. Its publication attracted widespread attention for he turned his attention to the gene-editing technology. By telling the story of Clara, an artificial friend (AF) designed to accompany "lifted" children, the author revealed the ethical problems caused by the application of gene-editing technology to "lifted" children. From the theoretical perspective of bioethics and its basic principles, this paper interpreted the ethical issues of gene-editing technology from three aspects that: "lifted" technology, "lifted" technology implementer, and "lifted" technology implementation consequence, and analyzed Kazuo Ishiguro’s technical ethics proposition.

Legal Regulatory Approach of Germline Cell Gene Editing / 中国医学伦理学

Germline cell gene editing is a potentially revolutionary technology that can be used to treat and prevent many genetic diseases, such as cystic fibrosis and hemophilia. Although this technology has aroused widespread discussion in the medical community and the public, its legal regulatory approach has not yet been fully determined. By summarizing and studying the experience of relevant foreign laws and regulations, this paper analyzed and summarized the current legal situation in China, and explored three ethical topics of social equality, individual subjectivity, and intergenerational rights. Combining the existing legal norms and relevant ethical considerations, the legal regulatory approach for germline cell gene editing was proposed in view of the weak operability of the law, the blurred boundaries of the legislation, and the insufficiently perfect ethical review mechanism. To better ensure that the technology can benefit mankind on the premise of eliminating risks, the following suggestions were put forward: a specialized law should be formulated based on clear legislative principles to adjust and guide the improvement of the ethical review mechanism of germline cell gene editing. It is hoped that promoting the progress of germline cell gene editing technology through in-depth research, and providing useful reference for the formulation of relevant laws and ethical policies.

Progress in RNA-targeting and Gene Editing Therapies for Transthyretin Amyloidosis Cardiomyopathy / 罕见病研究

Transthyretin(TTR) protein is a tetramer protein, synthesized mainly by the liver. TTR can be misfolded and deposited as amyloid fibrilae and deposited in the myocardial interstroma leading to transthyroxin amyloidosis cardiomyopathy (ATTR-CM). ATTR-CM was included in China's First List of Rare Diseases. Therapeutic strategies for ATTR-CM include blocking TTR synthesis in the liver, stabilizing TTR tetramers and destroying TTR fibra. Small molecule drugs such as tafamidis and diflunisal offer new treatment options for patients. Chlorobenzolic acid became the first drug approved by the U.S. Food and Drug Administration for the treatment of ATTR-CM. Small interfering RNA(siRNA)patisiran and antisense oligonucleotide (ASO)inotersen block TTR expression in the liver and have been approved for the treatment of ATTR variant polyneuropathy (ATTRv-PN)and are in phase Ⅲ trials for the treatment of ATTR-CM. Other siRNA drugs, vutrisiran, and ASO, eplontersen, are being evaluated for clinical efficacy. This article reviews the development of RNA-targeted therapeutics and gene-editing drugs using CRISPR-Cas9.

Construction of interferon alpha/beta receptor subunit 1 gene knockout Caco-2 cell line based on CRISPR/Cas9 system / 中国生物制品学杂志

@#Objective To knockout interferon alpha/beta receptor subunit 1(IFNAR1) gene in human colorectal adenocarcinoma cells Caco-2 using clustered regularly interspaced short palinmic repeats(CRISPR)/CRISPR-associated protein 9(Cas9)system to construct IFNAR1 knockout Caco-2 cell line.Methods The single guide RNA(sgRNA)sequence was designed to specifically recognize the exon region of IFNAR1 gene using CRISPR/Cas9 technology,and the LentiCRISPRv2-IFNAR1-sgRNA recombinant plasmid was constructed.Caco-2 cells were infected with the plasmid packaged by lentivirus and screened by puromycin resistance.The obtained monoclonal cell lines were cultured by limited dilution method,which were verified for the effect of IFNAR1 gene knockout by target gene sequencing and Western blot,and detected for the mRNA levels of CXC chemokine ligand 10(CXCL10)and interferon-stimulatd gene 20(ISG20)in IFNAR1knockout cells by adding exogenous IFNβ.Results Sequencing results of plasmid LentiCRISPRv2-IFNAR1-sgRNA showed that the insertion sites were all located at the sticky end of BsmBⅠenzyme digestion.Two IFNAR1 knockout monoclonal cell lines were obtained.The sequencing results showed that Caco-2-IFNAR1-KO1 had 5 bp deletion in the sixth exon of IFNAR1,and Caco-2-IFNAR1-KO2 had 18 bp deletion and 1 bp insertion in the seventh exon.Compared with wild-type Caco-2 cells,Caco-2-IFNAR1-KO1 and Caco-2-IFNAR1-KO2 cells showed no expression of IFNAR1 protein.Compared with no IFNβ stimulation,the mRNA levels of CXCL10 gene(t = 0.566 and 1.268 respectively,P>0.05)and ISG20 gene(t =1.522 and 1.733 respectively,P>0.05)in Caco-2-IFNAR1-KO1 and Caco-2-IFNAR1-KO2 cells stimulated by 50 ng/mL IFNβ showed no significant increase.While compared with those of wild-type Caco-2 cells,the mRNA levels of CXCL10gene(t = 6.763 and 6.777 respectively,P<0.05)and ISG20 gene(t = 5.664 and 5.65 respectively,P<0.05)in Caco-2-IFNAR1-KO1 and Caco-2-IFNAR1-KO2 cells decreased significantly under the stimulation of 50 ng/mL exogenous IFNβ.Conclusion Caco-2 cell line with IFNAR1 knockout was successfully constructed by using CRISPR/Cas9 technology,and the downstream molecules activated by IFNAR(interferon alpha/beta receptor)in this cell line were obviously inhibited,which provided a powerful tool for further exploration of the innate immune response and replication packaging mechanism of Caco-2 cells after virus infection.

The past, present and future of heart transplantation / 器官移植

Heart transplantation is one of the most effective strategies to treat end-stage heart failure. Multiple challenges, such as difficulty in preservation of heart allograft, rejection and postoperative complications, emerge in heart allotransplantation. After decades of research and practice, most problems have been resolved. Nevertheless, the shortage of donor organs has become increasingly prominent. To alleviate the shortage of donor organs, artificial heart and heart xenotransplantation have captivated attention, and obtained significant progress in recent years. The application of artificial heart in clinical practice has significantly enhanced the survival rate of patients with end-stage heart failure, which is expected to become the standard treatment for end-stage heart failure. Heart xenotransplantation still faces many challenges, which is still far from clinical application. In this article, the history of heart transplantation, development of heart allotransplantation, use of artificial heart and research progress on heart xenotransplantation were reviewed, and the future development direction of heart transplantation was predicted.