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.

Breeding and genotyping of T lymphocyte-conditional Spi1 knockout mice / 安徽医科大学学报

Objective @#To breed and identify the T lymphocyte-conditional Spi1 knockout mice for the further in- vestgation of the specific role of Spi1-encoded protein PU. 1 . @*Methods @#The Lck-Cre mice were mated with Spi1 flox/flox mice to obtain Lck-Cre ×Spi1 flox/flox mice (T lymphocyte-specific Spi1 knockout mice) , and the genotype was determined by polymerase chain reaction (PCR) and agarose gel electrophoresis . Magnetic beads were used to sort out the splenic T lymphocytes , and the knockdown efficiency of PU. 1 in T cells was detected by Western blot , quantitative real-time PCR ( qPCR) and flow cytometry. @*Results @#The Lck-Cre ×Spi1 flox/flox mouse genotype was stably inherited . Compared with Spi1 flox/flox mice , the expression level of PU. 1 was significantly reduced in splenic T cells of Lck-Cre ×Spi1 flox/flox mice . @*Conclusion @#In this study , the T lymphocyte-specific Spi1 knockout mice was successfully constructed by applying Cre/LoxP system and CRISPR/Cas9 technology , which provided a reliable an- imal model for the subsequent experiments of the specific role of PU. 1 in T cell-related diseases .

Construction of Raji-Luc CD19 KO Lymphoma Cell Line Using CRISPR/Cas9 Technology / 现代检验医学杂志

Objective To construct Raji-Luc lymphoma cells with CD19 knockout using CRISPR/Cas9 technology and preliminarily validate their immune escape ability.Methods PB-CRISPR-CD19 small guide RNA(sgRNA)plasmids was constructed,the optimal sgRNA sequence was screened,and Raji-Luc cells with pCAG-PBase,PB-CD19 sgRNA,and PB-CRISPR-Cas9 were co-transfected.Stable knockout monoclonal cell lines were screened by flow sorting and limit dilution method and the knockout effect was verified through gene sequence testing.The expression of luciferase on the surface of the cell line was detected by microplate reader,CD19 CAR-T and CD38 CAR-T previously constructed in the laboratory were used as effector cells,and the immune escape ability of Raji-Luc CD19 KO cell line was verified by universal luciferase chemiluminescence method.Results The transfection efficiency of Raji-Luc CD19 KO cells prepared by electro transfection was high,and the knockout efficiency of the two monoclonal cells was more than 99%.There was no significant difference in luciferase expression compared to the original Raji-Luc cells,and CD19 CAR-T cells could not be activated to the kill them.Conclusion Successfully constructed Raji-Luc CD19 KO lymphoma cell line.

Construction of HIF-1α gene knockout plasmid and functional verification in naked mole rats based on CRISPR/Cas9 system / 中国实验动物学报

Objective To construct plasmids and knock out HIF-1α gene expression in an naked mole rat skin fibroblasts(NSF)cell line using CRISPR/Cas9 genomic editing technology,to provide an in vitro cell model for studying the mechanism of hypoxia tolerance and the occurrence and development of hypoxia-related diseases in naked mole rats.Methods We designed four pairs of single guide RNA(sgRNA)sequences targeting exons 1～4 of the NSF HIF-1αgene and successfully constructed an expression plasmid.The plasmid with the optimal sgRNA was identified and transfected into 293T cells,and the supernatant was used for detecting the virus titer.Lentivirus particles carrying sgRNAs of HIF-1α were transfected into NSF cells which express Cas9 protein,based on a previous protocol.After transfection,fluorescence signals were observed under a fluorescence microscope,and HIF-1α expression in NSF cells was detected by Western Blot and T7 endonuclease 1(T7E1)analysis.Results Sanger sequencing showed that the designed sgRNA was successfully inserted into pX459 and pKLV2-U6-sgRNA2 vectors,demonstrating successful construction of a recombinant plasmid for transfection.T7E1 digestion successfully removed three bands and the target efficiency of sgRNA was 54％.Western Blot showed that the HIF-1α gene was successfully knocked out and its protein level was significantly reduced in NSF cells from naked mole rats(P=0.0019).There were no obvious morphological changes in HIF-1α-knockout cells under the microscope,and gene knockout had no obvious effect on cell proliferation.Conclusions We successfully constructed an HIF-1α-knockout cell line using CRISPR/Cas9 technology,to provide an experimental basis for further studies of the biological function of HIF-1α,as well as the mechanism of hypoxia tolerance in naked mole rats.The result also provide a theoretical foundation for the prevention and treatment of hypoxia-related diseases.

Construction of Dmd Gene Mutant Mice and Phenotype Verification in Muscle and Immune Systems / 实验动物与比较医学

Objective The aim is to utilize CRISPR/Cas9 gene editing technology to construct Dmd gene mutant mice with a point mutation in exon 23 of the Dmd gene. Subsequently, the phenotypic changes of the mice in muscles and immune systems are analyzed and verified, providing an evaluation model for Duchenne muscular dystrophy and other related diseases.MethodsBased on the sequence characteristics of exon 23 of the Dmd gene, small guide RNA (sgRNA) was designed and synthesized. Cas9 mRNA, sgRNA fragments, and oligo donor DNA were microinjected into fertilized eggs of C57BL/6J mice. After transferring the fertilized eggs to surrogate mice, F0 generation mice were born. After mating with F0 generation mice, offspring mice were obtained, and Dmd gene positive mutant (DmdMu/+) mice were obtained after genotype identification. Male hemizygous DmdMu/+(DmdMu/Y) mice were selected for phenotype validation. The body weight of live 3- and 9-month-old mice were recorded. Muscle tension was evaluated through the grid test. Hearts and semitendinosus muscles were collected, and the histopathological changes were observed using HE staining. Further, the expression of Dmd protein in muscle tissue of 9-month-old mice was analyzed by Western blotting.An acute inflammation model was established in DmdMu/Y mice using lipopolysaccharide induction. Peripheral blood from the submandibular vein was collected, and the changes in the proportion of neutrophils and monocytes were detected by flow cytometry.Results The results of genome sequencing and Western blotting confirmed the successful construction of Dmd gene point mutant mice (DmdMu/+ mice). Dmd protein expression was not detected in skeletal muscle and myocardium of DmdMu/+ mice, and it was significantly reduced compared to wild-type C57BL/6J mice (P<0.05). Compared with wild-type mice of the same background, DmdMu/Y mice at 3 and 9 months of age showed significant weight loss (P<0.01) and decreased muscle tension (P<0.05). 9-month-old DmdMu/Y mice exhibited significant pathological changes in skeletal muscle and myocardium, including widening of intermuscular space. Under normal condition, compared with wild-type mice, the proportion of neutrophils and monocytes in the peripheral blood of 3-month-old DmdMu/Y mice was significantly lower than that of wild-type mice (P<0.01). After lipopolysaccharide stimulation, the proportion of neutrophils in peripheral blood of 3-month-old DmdMu/Y mice remained significantly lower compared to that of wild-type mice (P<0.01). The proportion of neutrophils in peripheral blood of 9-month-old DmdMu/Y mice significantly decreased after lipopolysaccharide induction (P<0.01), with a trend of change observed in monocytes between groups.Conclusion The successful construction of the Dmd gene mutant mouse model has confirmed the vital function of Dmd gene in maintaining normal muscle tissue morphology and muscle tone. It preliminarily indicated that Dmd gene deletion could significantly reduce the proportion of neutrophils in peripheral blood, offering a new perspective for the study of immune system alterations in Duchenne muscular dystrophy patients.

Application of CRISPR/Cas9 gene editing technology in the research of precision oncology / 中国肿瘤生物治疗杂志

@#[摘 要] CRISPR/Cas9基因编辑技术通过精准定位和修改基因序列，可以识别与细胞增殖、迁移、侵袭和化疗耐药性相关的基因，不仅为理解肿瘤发生发展的分子机制奠定了基础，还为实现肿瘤的精准治疗提供了一种方便、高效的方法。由于其具有低成本、高效率的优点，被广泛地应用于精准肿瘤学的基础和临床研究当中，包括用于探寻抗肿瘤药物耐药靶点、筛查驱动基因、优化CAR-T和TCR-T细胞，以及筛选肿瘤靶向基因等。目前，已开展了十余项项使用CRISPR/Cas9技术治疗肿瘤的临床试验，策略多为利用CRISPR/Cas9技术敲除T细胞中的免疫检查点基因后回输患者，以达到免疫激活的效果，大多数研究仍处于Ⅰ期和Ⅱ期阶段。管CRISPR/Cas9基因编辑技术在肿瘤研究与治疗领域展现出了巨大潜力，但仍需面对脱靶效应，以及永久编辑可能带来的弊端等瓶颈，其实际临床效用仍有待更多的深入研究和大规模临床试验的严格验证。

Construction and gene identification of myeloid specific Spi1 knockout mice / 安徽医科大学学报

Objective @#To construct myeloid specific Spi1 gene knockout mice and analyze their genotypes , so as to provide animal model basis for the study of pathological mechanism of diseases and drug targets .@*Methods @#According to the principle of CRISPR/Cas9 technology and C re/LoxP system , sgRNA and Donor vectors were de signed and constructed . The transcript of Exon 2 ( Exon 2) was used as the knockout region , and Loxp elements were placed on both sides of Exon 2 . Cas9 protein , sgRNA and Donor vector were mixed and microinj ected into the fertilized eggs of C57BL/6J mice , the fertilized eggs were transplanted into the uterus of C57BL/6J pregnant female mice , and F0 generation was obtained after 19 ~ 20 days . Positive F0 mice were mated with C57BL/6J mice to ob tain stable F1 Spi1 flox/ + mice . Spi1 flox/ + mice of F1 generation were selfed to obtain Spi1 flox/flox mice . Spi1 flox/flox mated with Lyz2-Cre + mice to obtain Spi1 flox/ + /Lyz2-Cre + mice , and then mated with Spi1 flox/flox , the Spi1 flox/flox/Lyz2-Cre + mice were myeloid specific Spi1 gene knockout ( KO) mice . Spi1 flox/flox/Lyz2-cre - mice were used as wild type (WT) mice . DNA of WT and KO mice was extracted , and the genotypes were identified by agarose gel electro phoresis after PCR amplification . Western blot was used to detect the expression of spleen focus forming virus proviral integration oncogene , Spi - 1 /purine rich box - 1(PU . 1) in immune cells of WT and KO mice .@*Results@#The results of PCR identification showed that the genotype of mice with only 220 bp amplified by flox primer was Spi1 flox/flox homozygote , and the genotype of mice with 700 bp amplified by Lyz2-Cre primer was Lyz2-Cre + . Western blot showed that compared with WT group , the protein PU . 1 was not expressed in bone marrow derived macropha ges (BMDMs ) and peritoneal macrophages (PM) in KO group (P < 0.01) . There was no significant difference of statistics in the expression level of PU . 1 in T cells between KO mice and WT mice . The results of PCR and West ern blot showed that myeloid specific Spi1 KO mice were successfully constructed . @*Conclusion @#The myeloid spe cific Spi1 gene KO mice are successfully constructed and identified , which provides animal model basis for further revealing the potential mechanism of PU . 1 inimmune regulation .

Phosphatidylinositol 3-kinases Play a Suppressive Role in Electrotaxis of Dictyostelium Cells Through Akt and ERK / 生物化学与生物物理进展

ObjectivePhosphatidylinositol 3 kinases (PI3Ks) play an important role in cell directional movement by regulating F-actin. However, the structure and function of PI3Ks are complex. The role of PI3Ks in cell electrotaxis is not fully understood. Therefore, in this study, the model organism Dictyostelium discoideum cells were used as experimental materials to explore the role of PI3K1 and PI3K2 in electrotaxis. MethodsFirstly, PI3K1 coding gene pikA knockout mutant and PI3K2 coding gene pikB knockout mutant were constructed by CRISPR/Cas9 system. Secondly, two mutants were placed in a DC electric field with a strength of 12 V/cm and the electrotaxis were analyzed. ResultsData analysis showed that the direction index of wild-type cells in DC electric field was (0.86±0.03), while the direction index of pikA- and pikB- mutants in DC electric field was (0.95±0.02) and (0.94±0.03), respectively. In addition, the average trajectory speed of wild-type cells in the electric field was (3.34±0.08) μm/min, while the average trajectory speed of pikA- and pikB- mutants were (4.85±0.20) μm/min and (5.48±0.15) μm/min, respectively. The t test showed that there were significant differences in the directedness index and speed between the mutant and wild type. Western blot results showed that both phosphorylated Akt and phosphorylated ERK were significantly increased in pikA- and pikB- mutants. ConclusionPI3K1 and PI3K2 may inhibit the electrotaxis of Dictyostelium discoideum cells by increasing the activity of Akt and ERK.

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.

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.

The progress of the gene editing therapy of inherited retinal diseases based on CRISPR/Cas9 / 中华眼底病杂志

Inherited retinal diseases (IRDs) are the major cause of refractory blinding eye diseases, and gene replacement therapy has already made preliminary progress in the treatment of IRDs. For IRDs that cannot be treated by gene replacement therapy, gene editing provides an alternative therapeutic method. Strategies like disruption of pathogenic variants with or without gene augmentation therapy and precise repair of pathogenic variants can be applied for IRDs with various inheritance patterns and pathogenic variants. In animal models of retinitis pigmentosa, Usher syndrome, Leber congenital amaurosis, cone rod cell dystrophy, and other disorders, CRISPR/Cas9, base editing, and prime editing showed the potential to edit pathogenic variations in vivo, indicating a promising future for gene editing therapy of IRDs.

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.

CRISPR/Cas9-mediated Knockout of KIFC1 Inhibits Proliferation and Induces Apoptosis of Cervical Cancer Cells / 肿瘤防治研究

Objective To investigate the functions of the KIFC1 gene in tumor cells and its effect on the proliferation of cervical cancer cells. Methods We designed sgRNAs targeting the KIFC1 gene and constructed a recombinant plasmid based on the pSpCas9 (BB)-2A-GFP vector, which was co-transfected into HeLa cells. We screened monoclonal knockout cell lines through flow cytometry sorting, limited dilution inoculation of cells, and sequencing. RT-qPCR, Western blot, and immunofluorescence were used to detect the transcription and protein expression levels of KIFC1 in knockout cells. Cell phenotypes such as nucleus and microtubule cytoskeleton were observed using phase-contrast microscopy and fluorescence confocal microscopy. Cell proliferation, cell cycle, and apoptosis were analyzed by growth curve plotting, EdU labeling, and acridine orange staining. Results The deletion of the KIFC1 gene resulted in the abnormal phenotypes of HeLa cells, with increased numbers of multinuclei, micronucleus, and disordered microtubules. The cell cycle was disrupted, accompanied with a significant increase in the ratio of late apoptotic cells and a decrease in cell proliferation (all P < 0.05). Conclusion KIFC1 gene deletion affects the assembly of microtubules and cell division in HeLa cells, leading to abnormal nuclear morphology, chromatin elimination, cell cycle arrest, and increased cell apoptosis.

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.

Development of porcine induced pluripotent stem cells with a CD163 reporter system / 生物工程学报

As main recipient cells for porcine reproductive and respiratory syndrome virus (PRRSV), porcine alveolar macrophage (PAM) are involved in the progress of several highly pathogenic virus infections. However, due to the fact that the PAM cells can only be obtained from primary tissues, research on PAM-based virus-host interactions remains challenging. The improvement of induced pluripotent stem cells (iPSCs) technology provides a new strategy to develop IPSCs-derived PAM cells. Since the CD163 is a macrophage-specific marker and a validated receptor essential for PRRSV infection, generation of stable porcine induced pluripotent stem cells lines containing CD163 reporter system play important roles in the investigation of IPSCs-PAM transition and PAM-based virus-host interaction. Based on the CRISPR/Cas9- mediated gene editing system, we designed a sgRNA targeting CD163 locus and constructed the corresponding donor vectors. To test whether this reporter system has the expected function, the reporter system was introduced into primary PAM cells to detect the expression of RFP. To validate the low effect on stem cell pluripotency, we generated porcine iPSC lines containing CD163 reporter and assessed the pluripotency through multiple assays such as alkaline phosphatase staining, immunofluorescent staining, and EdU staining. The red-fluorescent protein (RFP) expression was detected in CD163-edited PAM cells, suggesting that our reporter system indeed has the ability to reflect the expression of gene CD163. Compared with wild-type (WT) iPSCs, the CD163 reporter-iPSCs display similar pluripotency-associated transcription factors expression. Besides, cells with the reporter system showed consistent cell morphology and proliferation ability as compared to WT iPSCs, indicating that the edited-cells have no effect on stem cell pluripotency. In conclusion, we generated porcine iPSCs that contain a CD163 reporter system. Our results demonstrated that this reporter system was functional and safe. This study provides a platform to investigate the iPS-PAM development and virus-host interaction in PAM cells.

Identification of the target site of antimicrobial peptide AMP-17 against Candida albicans / 生物工程学报

Candida albicans is one of the major causes of invasive fungal infections and a serious opportunistic pathogen in immunocompromised individuals. The antimicrobial peptide AMP-17 has prominent anti-Candida activity, and proteomic analysis revealed significant differences in the expression of cell wall (XOG1) and oxidative stress (SRR1) genes upon the action of AMP-17 on C. albicans, suggesting that AMP-17 may exert anti-C. albicans effects by affecting the expression of XOG1 and SRR1 genes. To further investigate whether XOG1 and SRR1 genes were the targets of AMP-17, C. albicans xog1Δ/Δ and srr1Δ/Δ mutants were constructed using the clustered regulatory interspaced short palindromic repeats-associated protein 9 (CRISPR/Cas9) system. Phenotypic observations revealed that deletion of two genes had no significant effect on C. albicans growth and biofilm formation, whereas XOG1 gene deletion affected in vitro stress response and mycelium formation of C. albicans. Drug sensitivity assay showed that the MIC80 values of AMP-17 against xog1Δ/Δ and srr1Δ/Δ mutants increased from 8 μg/mL (for the wild type C. albicans SC5314) to 16 μg/mL, while the MIC80 values against srr1Δ/Δ: : srr1 revertants decreased to the level of the wild type SC5314. In addition, the ability of AMP-17 to inhibit biofilm formation of both deletion strains was significantly reduced compared to that of wild type SC5314, indicating that the susceptibility of the deletion mutants to AMP-17 was reduced in both the yeast state and during biofilm formation. These results suggest that XOG1 and SRR1 genes are likely two of the potential targets for AMP-17 to exert anti-C. albicans effects, which may facilitate further exploration of the antibacterial mechanism of novel peptide antifungal drugs.

Application of CRISPR-Cas9 gene editing technology in crop breeding / 生物工程学报

The CRISPR-Cas9 system is composed of a clustered regularly interspaced short palindromic repeat (CRISPR) and its associated proteins, which are widely present in bacteria and archaea, serving as a specific immune protection against viral and phage secondary infections. CRISPR-Cas9 technology is the third generation of targeted genome editing technologies following zinc finger nucleases (ZFNs) and transcription activator like effector nucleases (TALENs). The CRISPR-Cas9 technology is now widely used in various fields. Firstly, this article introduces the generation, working mechanism and advantages of CRISPR-Cas9 technology; secondly, it reviews the applications of CRISPR-Cas9 technology in gene knockout, gene knock-in, gene regulation and genome in breeding and domestication of important food crops such as rice, wheat, maize, soybean and potato. Finally, the article summarizes the current problems and challenges encountered by CRISPR-Cas9 technology and prospects future development and application of CRISPR-Cas9 technology.

CRISPR/Cas9-mediated endogenous TCR knockout enhances TCR-T cells targeted killing HPV16-positive cervical cancer cells / 中国肿瘤生物治疗杂志

@#[摘 要] 目的：基于CRISPR/Cas9基因编辑技术制备无内源TCR的TCR-T细胞并鉴定其在体外杀伤HPV16阳性宫颈癌SiHa细胞的功能。方法：培养健康志愿者外周血CD8+ T细胞和Jurkat细胞，CRISPR/Cas9基因编辑技术敲除CD8+ T、Jurkat细胞的TCR基因，制备过表达转基因TCR的重组慢病毒，在敲除内源性TCR的CD8+ T和Jurkat细胞中用慢病毒过表达转基因TCR制备TCR-T细胞，多色FCM检测TCR-T细胞中TCR和CD3的表达水平，荧光素酶活性实验检测TCR-T细胞对HPV16阳性SiHa细胞的杀伤效率。结果：CRIPSR/Cas9基因编辑技术高效地敲除了外周血CD8+ T细胞和Jurkat细胞中的TRAC和TRBC基因，敲除效率分别为（81.4±4.5）%、（98.5±0.07）%，制备的无内源TCR的TCR-T细胞高效表达转基因TCR，在外周血CD8+ T和Jurkat细胞中表达率为（66.0±17.8）%、（97.3±2.6）%，敲除内源TRAC和TRBC基因有效增强CD8+ T和Jurkat细胞膜表达转基因TCR（均P<0.01），敲除内源TCR增强TCR-T细胞特异性杀伤HPV16阳性的SiHa细胞[（71.4±1.0）% vs （35.1±2.0）%，P<0.01）]。结论：无内源TCR的TCR-T细胞显著增强转基因TCR的表达和对HPV16阳性宫颈癌SiHa细胞的靶向杀伤能力，为提高TCR-T细胞的临床疗效提供了实验依据。

Construction of CRISPR/Cas9 system targeting mouse Tsc1 and Tsc2 gene and verification of targeting effectiveness / 中国生物制品学杂志

@#ObjectiveTo design and construct CRISPR/Cas9 gene editing system targeting Tsc1 and Tsc2 genes,and verify the effectiveness of gene editing at cellular level.MethodsThree sgRNA guide sequences were designed for mouse Tsc1 and Tsc2 genes respectively. The sgRNA expression vector was constructed and co-transfected with the Cas9 expression plasmid into mouse N2a cells. After the positive cells were obtained through drug screening,the DNA fragments at the targeting site were amplified by PCR,and the targeting efficiency was verified by TA clone sequencing.ResultsThe five targets of Tsc1-M-sgRNA2 and Tsc1-M-sgRNA3 of Tsc1 gene and Tsc2-M-sgRNA1,Tsc2-M-sgRNA2 and Tsc2-M-sgRNA3 of Tsc2 gene were all edited,and the editing efficiency was 40%,80%,30%,30% and 20%,respectively.ConclusionA CRISPR-Cas9 gene editing system with editing efficiency targeting mouse Tsc1 and Tsc2 genes was successfully constructed.

Generation of Mlk3 KO mice by CRISPR/Cas9 and its effect on blood pressure / 生物工程学报

To explore the effect of Mlk3 (mixed lineage kinase 3) deficiency on blood pressure, Mlk3 gene knockout (Mlk3KO) mice were generated. Activities of sgRNAs targeted Mlk3 gene were evaluated by T7 endonuclease I (T7E1) assay. CRISPR/Cas9 mRNA and sgRNA were obtained by in vitro transcription, microinjected into zygote, followed by transferring into a foster mother. Genotyping and DNA sequencing confirmed the deletion of Mlk3 gene. Real- time PCR (RT-PCR), Western blotting or immunofluorescence analysis showed that Mlk3KO mice had an undetectable expression of Mlk3 mRNA or Mlk3 protein. Mlk3KO mice exhibited an elevated systolic blood pressure compared with wild-type mice as measured by tail-cuff system. Immunohistochemistry and Western blotting analysis showed that the phosphorylation of MLC (myosin light chain) was significantly increased in aorta isolated from Mlk3KO mice. Together, Mlk3KO mice was successfully generated by CRISPR/Cas9 system. MLK3 functions in maintaining blood pressure homeostasis by regulating MLC phosphorylation. This study provides an animal model for exploring the mechanism by which Mlk3 protects against the development of hypertension and hypertensive cardiovascular remodeling.