Novelty in improvement of CAR T cell-based immunotherapy with the aid of CRISPR system

Abstract Introduction Chimeric Antigen Receptor (CAR) T cells have tremendous potentials for cancer treatment; however, various challenges impede their universal use. These restrictions include the poor function of T cells in tumor microenvironments, the shortage of tumor-specific antigens and, finally, the high cost and time-consuming process, as well as the poor scalability of the method. Creative gene-editing tools have addressed each of these limitations and introduced next generation products for cell therapy. The clustered regularly interspaced short palindromic repeats-associated endonuclease 9 (CRISPR/Cas9) system has triggered a revolution in biology fields, as it has a great capacity for genetic manipulation. Method In this review, we considered the latest development of CRISPR/Cas9 methods for the chimeric antigen receptor T cell (CAR T)-based immunotherapy. Results The ability of the CRISPR/Cas9 system to generate the universal CAR T cells and also potent T cells that are persistent against exhaustion and inhibition was explored. Conclusion: We explained CRISPR delivery methods, as well as addressing safety concerns related to the use of the CRISPR/Cas9 system and their potential solutions.

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.

Aplicaciones clínicas de la herramienta CRISPR-Cas / Clinical Applications of the CRISPR-Cas Tool

Resumen El desarrollo de tecnologías para la edición del genoma ha abierto la posibilidad de apuntar directamente y modificar secuencias genómicas en casi todo tipo de células eucariotas. La edición del genoma ha ampliado nuestra capacidad para dilucidar la contribución de la genética a las enfermedades al promover la creación de modelos celulares y animales más precisos de procesos patológicos y ha comenzado a mostrar su potencial en una variedad de campos, que van desde la investigación básica hasta la biotecnología aplicada y biomédica. Entre estas tecnologías, el uso de las repeticiones palindrómicas cortas agrupadas regularmente espaciadas ha acelerado, en gran medida, el progreso de la edición de genes desde el concepto hasta la práctica clínica, generando, además, interés debido, no solo a su precisión y eficiencia, sino también a la rapidez y a los costos necesarios para su implementación en comparación con otras tecnologías de edición genómica. En esta revisión se presenta información recabada de publicaciones indexadas en la base de datos PubMed que se encontraron mediante el uso de palabras claves asociadas con la tecnología y que se filtraron para retener solo aquellas con evidencias de avances clínicamente relevantes y que permiten demostrar algunas de las aplicaciones que tiene esta tecnología en la investigación, pronóstico y tratamiento de enfermedades genéticas, cardiovasculares, virales, entre otras; esto con el objetivo de dar a conocer la situación actual de los avances en aplicaciones clínicas de la herramienta CRISPR-Cas y fomentar aún más la investigación en esta tecnología, la cual, tal como se evidencia a lo largo de esta revisión, posee una gran versatilidad y un amplio rango de aplicaciones, lo que ofrece una enorme oportunidad en el campo de la medicina genómica, pero que, a su vez, requiere un mayor fomento en su investigación para mejorar la tecnología y acercarla aún más a consolidar aplicaciones clínicas de uso seguro, confiable y consistente.

Abstract The development of genome editing technologies has opened up the possibility of directly targeting and modifying genomic sequences in almost all types of eukaryotic cells. Genome editing has expanded our ability to elucidate the contribution of genetics to disease by promoting the creation of more precise cellular and animal models of disease processes and has begun to show its potential in a variety of fields, ranging from basic research to applied and biomedical biotechnology. Among these technologies, the use of clustered regularly spaced short palindromic repeats have greatly accelerated the progress of gene editing from concept to clinical practice, further generating interest due not only to its precision and efficiency, but also to the speed and costs required for its implementation compared to other genomic editing methods. This review presents information collected from indexed publications in the PubMed database that were found by using keywords associated with the technology and filtered to retain only those with evidence of clinically relevant advances that demonstrate some of the applications that this technology has in research, prognosis, and treatment of genetic, cardiovascular, and viral diseases, among others; this with the aim of show the current situation of advances in clinical applications of the CRISPR-Cas tool and further encourage research in this technology, which, as evidenced throughout this review, has a great versatility and a wide range of applications, which offers an enormous opportunity in the field of genomic medicine but which, in turn, requires greater support in its research to improve the technology and bring it even closer to consolidating clinical applications of safe, reliable and consistent use.

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.

Evidence of a synthetic lethality interaction between SETDB1 histone methyltransferase and CHD4 chromatin remodeling protein in a triple negative breast cancer cell line

During the tumorigenic process, cancer cells may become overly dependent on the activity of backup cellular pathways for their survival, representing vulnerabilities that could be exploited as therapeutic targets. Certain molecular vulnerabilities manifest as a synthetic lethality relationship, and the identification and characterization of new synthetic lethal interactions may pave the way for the development of new therapeutic approaches for human cancer. Our goal was to investigate a possible synthetic lethal interaction between a member of the Chromodomain Helicase DNA binding proteins family (CHD4) and a member of the histone methyltransferases family (SETDB1) in the molecular context of a cell line (Hs578T) representing the triple negative breast cancer (TNBC), a subtype of breast cancer lacking validated molecular targets for treatment. Therefore, we employed the CRISPR-Cas9 gene editing tool to individually or simultaneously introduce indels in the genomic loci corresponding to the catalytic domains of SETDB1 and CHD4 in the Hs578T cell line. Our main findings included: a) introduction of indels in exon 22 of SETDB1 sensitized Hs578T to the action of the genotoxic chemotherapy doxorubicin; b) by sequentially introducing indels in exon 22 of SETDB1 and exon 23 of CHD4 and tracking the percentage of the remaining wild-type sequences in the mixed cell populations generated, we obtained evidence of the existence of a synthetic lethality interaction between these genes. Considering the lack of molecular targets in TNBC, our findings provided valuable insights for development of new therapeutic approaches not only for TNBC but also for other cancer types.

Molecular epidemiological analysis of tracing and analysis of Yersinia pestis strains isolated from two human plague outbreaks with unknown sources in Gansu Province / 中国热带医学

@#Abstract: Objective To conduct a molecular epidemiological tracing and analysis of Yersinia pestis strains isolated from two human plague outbreaks with unknown sources in Gansu Province, China. The results of this analysis would provide a basis for isolating and controlling the sources of Yersinia pestis. Methods The strains of Yersinia pestis isolated from two human plague outbreaks occurring on December 12, 2017, and September 27, 2019 were genotyped by the different region (DFR) and the clustered regularly interspaced short palindromic repeats (CRISPR). The repeat numbers of the variable number tandem repeat (VNTR) loci in the tested strains of Yersinia pestis were calculated by the multiple variable number tandem repeats analysis (MLVA), and the location of the phylogenetic tree of the tested strains was determined with the method of minimum spanning tree (MST) by the software BioNumerics 6.6. Results The strain of 20171212 lacked DFR01, DFR02, DFR03, DFR04, DFR13, DFR23, and the DFR type was identified as type 8. The space sequence of YPa was a1'-a2-a3-a4-a5-a6-a7-a35, the space sequence of YPb was b1-b2-b3-b4, the space sequence of YPc was c1-c2-c3, the gene cluster of CRISPR was Ca35', the genotype of CRISPR was 26'. MLVA clustering analysis showed that the strain clustered within in the cluster of Yuerhong pasture in Subei County and formed an independent branch. On the other hand, the strain of 20190927 lacked DFR01, DFR13 and DFR23, with the DFR type identified as type 1b. The space sequence of YPa was a1-a2-a3-a4-a5-a6-a7, the space sequence of YPb was b1-b2-b3-b4, the space sequence of YPc was c1-c2-c3, the gene cluster of CRSIPR was Ca7, the genotype of CRSIPR was 22 MLVA clustering analysis showed that the strain was located close to the cluster of Dangjinshan in Akesai County, and relatively distant from the cluster of Yuerhong pasture in Subei County. Conclusions The genotypes of strain 20171212 by DFR and CRISPR were consistent with the main genotypes of Y. pestis from Himalayana Marmota foci in Subei County, which confirmed that the human plague cases were naturally occurring locally. However, the strain gathered the cluster of Yuerhong pasture in Subei County, which indicated that the source of infection was not in Yanchiwan Town, but in the surrounding area of the Yuerhong pasture. The genotypes of strain 20190927 by DFR and CRISPR were in accordance with the main genotype of Y. pestis from Himalayana Marmota foci in Akesai County and were closer to the cluster of Dangjinshan in Aksai County than to

Berberine targeting TRIM25 induced cervical cancer HeLa cell apoptosis / 中国药理学通报

Aim To study the mechanism and target of apoptosis induced by berberine ( BBR) in cervical cancer HeLa cells. Methods Drug affinity responsive target stability (DARTS) and mass spectrometry (MS) were used to identify the potential binding proteins of berberine. The binding affinity between berberine and candidate target protein was detected by microscale thermophoresis technique (MST) , and cellular thermal shift assay (CETSA) was used to detect the binding of berberine to candidate target proteins in living cells. CRISPR/Cas9 gene editing technique was used to establish candidate target protein TRIM25-deficient tumor cell lines. CCK-8 assay and Annexin V/propidium iodide combined with flow cytometry were used to detect the inhibitory and apoptotic effects of berberine on wild-type and TRIM25-KO cells. Western blot was used to detect the effect of berberine on TRIM25 and its substrate protein levels.Results DARTS found that after berberine treatment, the sensitivity of TRIM25 to pronase proteolysis showed the most significant change. MST and CETSA assays showed that berberine directly bound to TRIM25 at molecular and cellular levels, and its dissociation constant was 4.02 μmol • L

CRISPR-assisted transcription activation by phase-separation proteins

The clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 system has been widely used for genome engineering and transcriptional regulation in many different organisms. Current CRISPR-activation (CRISPRa) platforms often require multiple components because of inefficient transcriptional activation. Here, we fused different phase-separation proteins to dCas9-VPR (dCas9-VP64-P65-RTA) and observed robust increases in transcriptional activation efficiency. Notably, human NUP98 (nucleoporin 98) and FUS (fused in sarcoma) IDR domains were best at enhancing dCas9-VPR activity, with dCas9-VPR-FUS IDR (VPRF) outperforming the other CRISPRa systems tested in this study in both activation efficiency and system simplicity. dCas9-VPRF overcomes the target strand bias and widens gRNA designing windows without affecting the off-target effect of dCas9-VPR. These findings demonstrate the feasibility of using phase-separation proteins to assist in the regulation of gene expression and support the broad appeal of the dCas9-VPRF system in basic and clinical applications.

Induction of Anxiety-Like Phenotypes by Knockdown of Cannabinoid Type-1 Receptors in the Amygdala of Marmosets / 神经科学通报·英文版

The amygdala is an important hub for regulating emotions and is involved in the pathophysiology of many mental diseases, such as depression and anxiety. Meanwhile, the endocannabinoid system plays a crucial role in regulating emotions and mainly functions through the cannabinoid type-1 receptor (CB1R), which is strongly expressed in the amygdala of non-human primates (NHPs). However, it remains largely unknown how the CB1Rs in the amygdala of NHPs regulate mental diseases. Here, we investigated the role of CB1R by knocking down the cannabinoid receptor 1 (CNR1) gene encoding CB1R in the amygdala of adult marmosets through regional delivery of AAV-SaCas9-gRNA. We found that CB1R knockdown in the amygdala induced anxiety-like behaviors, including disrupted night sleep, agitated psychomotor activity in new environments, and reduced social desire. Moreover, marmosets with CB1R-knockdown had up-regulated plasma cortisol levels. These results indicate that the knockdown of CB1Rs in the amygdala induces anxiety-like behaviors in marmosets, and this may be the mechanism underlying the regulation of anxiety by CB1Rs in the amygdala of NHPs.

Rapid visual detection of Vibrio parahaemolyticus by combining LAMP-CRISPR/Cas12b with heat-labile uracil-DNA glycosylase to eliminate carry-over contamination / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Vibrio parahaemolyticus is a major pathogen frequently found in seafood. Rapid and accurate detection of this pathogen is important for the control of bacterial foodborne diseases and to ensure food safety. In this study, we established a one-pot system that combines uracil-DNA glycosylase (UDG), loop-mediated isothermal amplification (LAMP), and clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 12b (Cas12b) for detecting V. parahaemolyticus in seafood. This detection system can effectively perform identification using a single tube and avoid the risk of carry-over contamination.

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.

Application of CRISPR/Cas systems in the nucleic acid detection of pathogens: a review / 中国血吸虫病防治杂志

Rapid, sensitive and specific detection tools are critical for the prevention and control of infectious diseases. The in vitro nucleic acid amplification assays, including polymerase chain reaction and isothermal amplification technology, have been widely used for the detection of pathogens. Recently, nucleic acid detection-based on clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated proteins (Cas) have been developed, which are rapid, highly sensitive, highly specific, and portable. This review describes the classification and principle of CRISPR/Cas systems and their applications in pathogen detection, and discusses the prospects of CRISPR/Cas systems.

Establishment and preliminary evaluation of a fluorescent recombinase-aided amplification/CRISPR-Cas12a system for rapid detection of Plasmodium falciparum / 中国血吸虫病防治杂志

Objective To establish a fluorescent assay for rapid detection of Plasmodium falciparum based on recombinaseaided amplification (RAA) and CRISPR-Cas12a system,and to preliminarily evaluate the diagnostic efficiency of this system.. Methods The 18S ribosomal RNA (rRNA) gene of P. falciparum was selected as the target sequence, and three pairs of RAA primers and CRISPR-derived RNA (crRNA) were designed and synthesized. The optimal combination of RAA primers and crRNA was screened and the reaction conditions of the system were optimized to create a fluorescent RAA/CRISPR-Cas12a system. The plasmid containing 18S rRNA gene of the P. falciparum strain 3D7 was generated, and diluted into concentrations of 1 000, 100, 10, 1 copy/μL for the fluorescent RAA/CRISPR-Cas12a assay, and its sensitivity was evaluated. The genomic DNA from P. vivax, P. malariae, P. ovum, hepatitis B virus, human immunodeficiency virus and Treponema pallidum was employed as templates for the fluorescent RAA/CRISPR-Cas12a assay, and its specificity was evaluated. Fifty malaria clinical samples were subjected to the fluorescent RAA/CRISPR-Cas12a assay and nested PCR assay, and the consistency between two assays was compared. In addition, P. falciparum strain 3D7 was cultured in vitro. Then, the culture was diluted into blood samples with parasite densities of 1 000, 500, 200, 50, 10 parasites/μL with healthy volunteers’ O-positive red blood cells for the RAA/CRISPR-Cas12a assay, and the detection efficiency was tested. Results The Pf-F3/Pf-R3/crRNA2 combination, 2.5 μL as the addition amount of B buffer, 40 min as the RAA reaction time, 37 °C as the reaction temperature of the CRISPR-Cas12a system were employed to establish the fluorescent RAA/CRISPR-Cas12a system. Such a system was effective to detect the plasmid containing 18S rRNA gene of the P. falciparum strain 3D7 at a concentration of 1 copy/μL, and presented fluorescent signals for detection of P. falciparum, but failed to detect P. ovum, P. malariae, P. vivax, T. pallidum, hepatitis B virus or human immunodeficiency virus. The fluorescent RAA/CRISPR-Cas12a system and nested PCR assay showed completely consistent results for detection of 50 malaria clinical samples (kappa = 1.0, P < 0.001). Following 6-day in vitro culture of the P. falciparum strain 3D7, 10 mL cultures were generated and the fluorescent RAA/CRISPR-Cas12a system showed the minimal detection limit of 50 parasites/μL. Conclusion The fluorescent RAA/CRISPR-Cas12a system is rapid, sensitive and specific for detection of P. falciparum, which shows promising value for rapid detection and risk monitoring of P. falciparum.

Construction and validation of sheep VASA gene knock-in vector based on CRISPR/Cas9 system / 生物工程学报

This study aimed to explore the expression changes of VASA gene in sheep testis development and to construct VASA gene knock-in vector to prepare for the study on the differentiation of sheep germ cells in vitro. The testicular tissues of 3-month-old (3M) and 9-month-old (9M) sheep which represent immature and mature stages, respectively, were collected. The differential expression of VASA gene was analyzed by quantitative real-time PCR (qPCR) and Western blotting, and the location of VASA gene was detected by immunohistochemistry. The sgRNA targeting the VASA gene was designed and homologous recombination vectors were constructed by PCR. Subsequently, plasmids were transferred into sheep ear fibroblasts. The VASA gene was activated in combination with CRISPR/dCas9 technology to further verify the efficiency of the vector. The results showed that the expression level of VASA gene increased significantly with the development of sheep testis (P < 0.01), and was mainly located in spermatocytes and round spermatids. The knock-in vector of VASA gene was constructed by CRISPR/Cas9 system, and the Cas9-gRNA vector and pEGFP-PGK puro-VASA vector were transfected into ear fibroblasts. After CRISPR/dCas9 system was activated, ear fibroblasts successfully expressed VASA gene. The results suggest that VASA gene plays a potential function in sheep testicular development and spermatogenesis, and the VASA gene knock-in vector can be constructed in vitro through the CRISPR/Cas9 system. Our results provided effective research tools for further research of germ cell development and differentiation.

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.

Construction of a 10rolGLP-1-expressing glucose-lowing Saccharomyces cerevisiae by CRISPR/Cas9 technique / 生物工程学报

To develop a novel glucose-lowering biomedicine with potential benefits in the treatment of type 2 diabetes, we used the 10rolGLP-1 gene previously constructed in our laboratory and the CRISPR/Cas9 genome editing technique to create an engineered Saccharomyces cerevisiae strain. The gRNA expression vector pYES2-gRNA, the donor vector pNK1-L-PGK-10rolGLP-1-R and the Cas9 expression vector pGADT7-Cas9 were constructed and co-transformed into S. cerevisiae INVSc1 strain, with the PGK-10rolGLP-1 expressing unit specifically knocked in through homologous recombination. Finally, an S. cerevisiae strain highly expressing the 10rolGLP-1 with glucose-lowering activity was obtained. SDS-PAGE and Western blotting results confirmed that two recombinant strains of S. cerevisiae stably expressed the 10rolGLP-1 and exhibited the desired glucose-lowering property when orally administered to mice. Hypoglycemic experiment results showed that the recombinant hypoglycemic S. cerevisiae strain offered a highly hypoglycemic effect on the diabetic mouse model, and the blood glucose decline was adagio, which can avoid the dangerous consequences caused by rapid decline in blood glucose. Moreover, the body weight and other symptoms such as polyuria also improved significantly, indicating that the orally hypoglycemic S. cerevisiae strain that we constructed may develop into an effective, safe, economic, practical and ideal functional food for type 2 diabetes mellitus treatment.

Construction of a stable centromere protein F overexpression cell model of hepatocellular carcinoma using CRISPR activation system / 生物工程学报

Current studies have shown that centromere protein F (CENPF) was overexpressed in hepatocellular carcinoma (HCC) and might be involved in the pathogenesis of HCC. Specifically, due to the very large molecular weight (358 kDa) of CENPF full length protein, only CENPF knock-down, but not overexpression models, were applied currently to explore the carcinogenicity of CENPF in HCC. Whether CENPF overexpression is a cause or an effect in HCC remains to be illustrated. We aimed to establish a CENPF overexpression cell model using CRISPR/dCas9 synergistic activation mediator (SAM) system with lentiMPHv2 and lentiSAMv2 vectors to explore the role of CENPF overexpression in HCC. Single guide RNAs (sgRNAs) that specifically identify the transcription initiation site of CENPF gene were synthesized and inserted into the lentiSAMv2 plasmid. Huh-7 and HCCLM3 cells were first transduced with lentiMPHv2 and then selected with hygromycin B. The cells were then transduced with lentiSAMv2 carrying specific sgRNA for CENPF gene, followed by blasticidin S selection. The mRNA and protein detection results of Huh-7 and HCCLM3 cells screened by hygromycin B and blasticidin S showed that the endogenous overexpression of CENPF can be induced by sgRNA1 and sgRNA4, especially by sgRNA4. By using the CRISPR/dCas9 technique, stable cell models with overexpressed CENPF were successfully constructed to explore the role of CENPF in tumorigenesis, which provides a reference for the construction of cell models overexpressing large molecular weight protein.

Advances in AAV-CRISPR/Cas9-Mediated Hemophilia A Gene Therapy --Review / 中国实验血液学杂志

Hemophilia A(HA) is an X-linked recessive bleeding disorder caused by mutations in coagulation factor VIII. Nowadays, exogenous coagulation factor replacement therapy is the main treatment. With the continuous development of gene therapy, new research directions have been provided for the treatment of hemophilia A. CRISPR-Cas9 technology was applied to select suitable target sites, and mediate the targeted knock-in and efficient expression of exogenous B-domain-deleted FⅧ variant gene through corresponding vectors for the treatment of hemophilia A.CRISPR-Cas9 technology is an emerging gene editing tool with great efficiency, safety and effectiveness, and has been widely used in hemophilia gene therapy research. This paper reviews the vector selection, construction of therapeutic genes, gene editing technology and selection of expression target sites for hemophilia A gene therapy at this stage.