1.Diagnostic value of combining the corneal stress-strain index with corneal biomechanical parameters for early keratoconus
Dian PU ; Qian KANG ; Zhiying MA ; Hongliang XU
International Eye Science 2025;25(9):1491-1494
AIM: To explore the diagnostic value of combining the corneal stress-strain index(SSI)with corneal biomechanical parameters for early keratoconus.METHODS:A retrospective study was conducted on 34 patients(53 eyes)with early keratoconus diagnosed and treated in our hospital from March 2022 to February 2024. Additionally, 112 normal volunteers(112 eyes)who underwent physical examinations in our hospital during the same period were selected as a healthy control group. The CorvisST equipment was utilized for measurement and recorded deformation with Scheimpflug camera to obtain 10 biomechanical parameters: first applanation time(A1T), first applanation length(A1L), velocity of initial applanation(Vin), second applanation time(A2T), second applanation length(A2L), velocity of outward applanation(Vout), highest concavity time(HCT), highest concavity depth of applanation(HCDA), highest concavity radius(HCR), and peak distance(PD), as well as stress-strain index(SSI), and the corneal biomechanical parameters of the two groups were compared. Furthermore, Logistic regression analysis was used to identify the risk factors for keratoconus, and ROC curves were plotted to analyze the biomechanical parameters of the cornea for early diagnosis of keratoconus.RESULTS:The SSI(0.77±0.17)in patients with keratoconus was lower than that in healthy controls(1.01±0.24; P<0.001). Patients with keratoconus had lower A1T, A1L, A2L, and HCR, and higher Vout, HCDA, and PD compared to healthy controls(all P<0.001). Logistic regression analysis showed that decreased SSI, A1T, A1L, A2L, and HCR, as well as increased Vout, HCDA, and PD, were risk factors for the development of keratoconus(P<0.001). ROC curve analysis showed that the AUC value for combined diagnosis of early keratoconus was 0.997, with a Youden's index of 0.954, sensitivity and specificity of 98.1% and 97.3%, respectively, and a 95% CI of 0.994-1.000.CONCLUSION:The combination of SSI and corneal biomechanical parameters holds diagnostic significance for early keratoconus, and the joint diagnostic value is even higher. It can be considered as a diagnostic or screening indicator for early keratoconus.
2.Acute effects and moderators of sedentary interruption on vascular function in adults:a Meta-analysis
Mingyue YIN ; Qian LIU ; Xiongzhuang XU ; Zhiying MA ; Shengji DENG ; Jianfeng DENG ; Yongming LI
Chinese Journal of Tissue Engineering Research 2025;29(17):3684-3696
OBJECTIVE:Prolonged sedentary behavior can acutely reduce peripheral and central vascular function,thereby increasing the risk of cardiovascular disease.Interrupting sedentary behavior may be a potential practical strategy to prevent vascular dysfunction caused by prolonged sitting.However,current research findings on its acute effects are inconsistent,and specific application recommendations have not yet been established.This study aims to perform a Meta-analysis on the acute effects of interrupting sedentary behavior on peripheral and central vascular function in adults and to explore its regulatory factors.METHODS:Following PRISMA reporting guidelines,literature search was conducted in March 2024 using the keywords of"interrupting,""sedentary,"and"vascular function"in the Web of Science Core Collection,PubMed,and China National Knowledge Infrastructure(CNKI)databases.Acute randomized crossover trials addressing the acute effects of interrupting sedentary behavior on peripheral and central vascular function in adults were included.Risk of Bias 2 developed by Cochrane was used to assess bias risk,and the Grading of Recommendations Assessment,Development,and Evaluation(GRADE)system was used to evaluate the evidence level.The"meta"and"metaphor"packages in R(version 4.2.0)were used for main effect aggregation(Hedge's g acted as the effect size indicator),publication bias testing,subgroup analysis,and regression analysis.RESULTS:Twenty-two randomized crossover trials involving 364 subjects(aged 21 to 70 years)were included.Meta-analysis results showed that compared with prolonged sitting,interrupting sedentary behavior acutely improved peripheral vascular blood flow volume(Hedge's g=0.48,95%confidence interval:0.14-0.82,P<0.01,I2=63%,low evidence level),shear stress(Hedge's g=0.65,95%confidence interval:0.37-0.93],P<0.01,I2=54%,moderate evidence level),and flow-mediated dilation(Hedge's g=0.43,95%confidence interval:0.15-0.72,P<0.01,I2=61%,moderate evidence level).Disease had a significant moderating effect on the main effect aggregation for blood flow volume(P=0.01 between subgroups),while the mode(P=0.01 between subgroups)and frequency(P=0.02 between subgroups)of interruptions had significant moderating effects on shear stress.Improvements in peripheral vascular shear stress from interrupting sedentary behavior were affected by age(β=-0.02,95%confidence interval:-0.03-0.01,P=0.09)and body mass index(β=-0.10,95%confidence interval:-0.18 to-0.02,P<0.01).Improvements in flow-mediated dilation were influenced by the total number of interruptions(β=-0.09,95%confidence interval:-0.17 to-0.01,P=0.03)and the duration of sitting during the control period(β=-0.21,95%confidence interval:-0.34 to-0.09,P<0.01).Each additional hour of sitting was associated with a 0.67%reduction in the acute improvement effect of flow-mediated dilation from interrupting sedentary behavior(P<0.01),and acute benefits disappeared when sitting control time exceeded 6 hours.A qualitative systematic review found that interrupting sedentary behavior did not significantly affect pulse wave velocity in various populations but could effectively prevent central vascular function decline in older adults due to prolonged sitting.CONCLUSION:Interrupting sedentary behavior acutely improves peripheral vascular blood flow volume(low evidence level),shear stress(moderate evidence level),and flow-mediated dilation(moderate evidence level)in adults and may prevent or protect against central vascular function decline in older adults due to prolonged sitting(very low evidence level).Characteristics of subjects(disease factors,sex,age,and body mass index),interruption intervention schemes(mode,frequency,total number of interruptions),and duration of sitting control all influence the acute improvement effects of interrupting sedentary behavior on vascular function.It is recommended that adults interrupt sedentary behavior with exercises involving large muscle groups,such as stair climbing,at high frequencies(e.g.,once every 40 minutes)with at least 5 minutes of moderate-to low-intensity activity each time,and limit the cumulative duration of prolonged sitting to no more than 6 hours per day.
3.CT and MRI manifestations of gastritis cystica profunda
Qian YANG ; Jing YUAN ; Ruili MAO ; Zhiying XUE ; Peng ZHONG ; Weiguo ZHANG ; Chunhua LIU
Chinese Journal of Medical Imaging Technology 2025;41(2):277-280
Objective To observe CT and MRI manifestations of gastritis cystica profunda(GCP).Methods Seventeen patients with GCP confirmed by operation or biopsy pathology were enrolled,and lesions'CT and MRI manifestations were observed.Results Among 17 cases,16 cases(16/17,94.12%)were found with single lesion and 1(1/17,5.88%)with diffuse multiple lesions.The lesion located in the fundus of stomach in 5 cases(5/17,29.41%),in the body of stomach in 4 cases(4/17,23.53%),in the cardia and antrum of stomach each in 3 cases(3/17,17.65%)and in the pylorus in 1 case(1/17,5.88%),while 1 case(1/17,5.88%)was found with diffused multiple lesions within stomach.Non-enhance CT showed local thickening of gastric wall in 10 cases(10/17,58.82%),all were isodensities,and the mucosa uniformly enhanced in contrast enhance CT(CECT).Predominately cystic lesion in 5 cases(5/17,29.41%)presented as submucosal cystic protrusions,and grew into the stomach cavity with circular or oblong low density in non-enhanced CT,while sandwich enhancement of mucosa was observed in CECT.Among these 5 cases(5/17,29.41%),MRI showed lesion confined to the submucosa with low signal on T1WI and high signal on T2WI,while diffusion weighted imaging showed unrestricted diffusion,and the enhancement pattern was consistent with that of CT in 2 cases.In other 2 cases(2/17,11.77%)with cystic-solid lesion,non-enhanced CT showed soft tissue density,while CECT showed lump-like stratified enhancement.Conclusion CT and MRI manifestations of GCP had certain characteristics.
4.CT and MRI manifestations of gastritis cystica profunda
Qian YANG ; Jing YUAN ; Ruili MAO ; Zhiying XUE ; Peng ZHONG ; Weiguo ZHANG ; Chunhua LIU
Chinese Journal of Medical Imaging Technology 2025;41(2):277-280
Objective To observe CT and MRI manifestations of gastritis cystica profunda(GCP).Methods Seventeen patients with GCP confirmed by operation or biopsy pathology were enrolled,and lesions'CT and MRI manifestations were observed.Results Among 17 cases,16 cases(16/17,94.12%)were found with single lesion and 1(1/17,5.88%)with diffuse multiple lesions.The lesion located in the fundus of stomach in 5 cases(5/17,29.41%),in the body of stomach in 4 cases(4/17,23.53%),in the cardia and antrum of stomach each in 3 cases(3/17,17.65%)and in the pylorus in 1 case(1/17,5.88%),while 1 case(1/17,5.88%)was found with diffused multiple lesions within stomach.Non-enhance CT showed local thickening of gastric wall in 10 cases(10/17,58.82%),all were isodensities,and the mucosa uniformly enhanced in contrast enhance CT(CECT).Predominately cystic lesion in 5 cases(5/17,29.41%)presented as submucosal cystic protrusions,and grew into the stomach cavity with circular or oblong low density in non-enhanced CT,while sandwich enhancement of mucosa was observed in CECT.Among these 5 cases(5/17,29.41%),MRI showed lesion confined to the submucosa with low signal on T1WI and high signal on T2WI,while diffusion weighted imaging showed unrestricted diffusion,and the enhancement pattern was consistent with that of CT in 2 cases.In other 2 cases(2/17,11.77%)with cystic-solid lesion,non-enhanced CT showed soft tissue density,while CECT showed lump-like stratified enhancement.Conclusion CT and MRI manifestations of GCP had certain characteristics.
5.Acute effects and moderators of sedentary interruption on vascular function in adults:a Meta-analysis
Mingyue YIN ; Qian LIU ; Xiongzhuang XU ; Zhiying MA ; Shengji DENG ; Jianfeng DENG ; Yongming LI
Chinese Journal of Tissue Engineering Research 2025;29(17):3684-3696
OBJECTIVE:Prolonged sedentary behavior can acutely reduce peripheral and central vascular function,thereby increasing the risk of cardiovascular disease.Interrupting sedentary behavior may be a potential practical strategy to prevent vascular dysfunction caused by prolonged sitting.However,current research findings on its acute effects are inconsistent,and specific application recommendations have not yet been established.This study aims to perform a Meta-analysis on the acute effects of interrupting sedentary behavior on peripheral and central vascular function in adults and to explore its regulatory factors.METHODS:Following PRISMA reporting guidelines,literature search was conducted in March 2024 using the keywords of"interrupting,""sedentary,"and"vascular function"in the Web of Science Core Collection,PubMed,and China National Knowledge Infrastructure(CNKI)databases.Acute randomized crossover trials addressing the acute effects of interrupting sedentary behavior on peripheral and central vascular function in adults were included.Risk of Bias 2 developed by Cochrane was used to assess bias risk,and the Grading of Recommendations Assessment,Development,and Evaluation(GRADE)system was used to evaluate the evidence level.The"meta"and"metaphor"packages in R(version 4.2.0)were used for main effect aggregation(Hedge's g acted as the effect size indicator),publication bias testing,subgroup analysis,and regression analysis.RESULTS:Twenty-two randomized crossover trials involving 364 subjects(aged 21 to 70 years)were included.Meta-analysis results showed that compared with prolonged sitting,interrupting sedentary behavior acutely improved peripheral vascular blood flow volume(Hedge's g=0.48,95%confidence interval:0.14-0.82,P<0.01,I2=63%,low evidence level),shear stress(Hedge's g=0.65,95%confidence interval:0.37-0.93],P<0.01,I2=54%,moderate evidence level),and flow-mediated dilation(Hedge's g=0.43,95%confidence interval:0.15-0.72,P<0.01,I2=61%,moderate evidence level).Disease had a significant moderating effect on the main effect aggregation for blood flow volume(P=0.01 between subgroups),while the mode(P=0.01 between subgroups)and frequency(P=0.02 between subgroups)of interruptions had significant moderating effects on shear stress.Improvements in peripheral vascular shear stress from interrupting sedentary behavior were affected by age(β=-0.02,95%confidence interval:-0.03-0.01,P=0.09)and body mass index(β=-0.10,95%confidence interval:-0.18 to-0.02,P<0.01).Improvements in flow-mediated dilation were influenced by the total number of interruptions(β=-0.09,95%confidence interval:-0.17 to-0.01,P=0.03)and the duration of sitting during the control period(β=-0.21,95%confidence interval:-0.34 to-0.09,P<0.01).Each additional hour of sitting was associated with a 0.67%reduction in the acute improvement effect of flow-mediated dilation from interrupting sedentary behavior(P<0.01),and acute benefits disappeared when sitting control time exceeded 6 hours.A qualitative systematic review found that interrupting sedentary behavior did not significantly affect pulse wave velocity in various populations but could effectively prevent central vascular function decline in older adults due to prolonged sitting.CONCLUSION:Interrupting sedentary behavior acutely improves peripheral vascular blood flow volume(low evidence level),shear stress(moderate evidence level),and flow-mediated dilation(moderate evidence level)in adults and may prevent or protect against central vascular function decline in older adults due to prolonged sitting(very low evidence level).Characteristics of subjects(disease factors,sex,age,and body mass index),interruption intervention schemes(mode,frequency,total number of interruptions),and duration of sitting control all influence the acute improvement effects of interrupting sedentary behavior on vascular function.It is recommended that adults interrupt sedentary behavior with exercises involving large muscle groups,such as stair climbing,at high frequencies(e.g.,once every 40 minutes)with at least 5 minutes of moderate-to low-intensity activity each time,and limit the cumulative duration of prolonged sitting to no more than 6 hours per day.
6.Analysis of factors influencing the complication of dry eye after corneal transplantation and construction of nomogram predictive model
Hongliang XU ; Qian KANG ; Zhiying MA
International Eye Science 2024;24(6):970-974
AIM: To analyze the influencing factors of postoperative dry eye complication after corneal transplantation and to build a nomogram prediction model.METHODS: Clinical data were collected on 117 patients who underwent corneal transplantation at our hospital from March 2021 to February 2023. They were divided into dry eye group(n=96)and non-dry eye group(n=21)according to whether there was a postoperative dry eye. The risk factors of postoperative complication of dry eye after corneal transplantation were analyzed, the nomogram prediction model for predicting postoperative complication of dry eye after corneal transplantation was constructed, and the internal validation of the model and the prediction efficacy were assessed by calibration curves and decision curves, respectively.RESULTS: Comorbid diabetes mellitus, comorbid sleep disorders, comorbid meibomian gland dysfunction, chronic eye drop abuse, chronic corneal contact lens wear, interleukin-6(IL-6), and tumor necrosis factor-α(TNF-α)were the risk factors for the complication of dry eye after corneal transplantation(P<0.05). The nomogram model predicted a C-index of 0.890(95% CI 0.877-0.903). The nomogram model had a threshold >0.07, and the nomogram model provided higher net clinical benefit than the single index in all cases.CONCLUSION: The nomogram model built in this study based on the factors affecting the complication of dry eye after corneal transplantation has a good predictive value for the complication of dry eye after corneal transplantation.
7.Analysis of the efficacy of adjusting the dose of imatinib with therapeutic drug monitoring in adjuvant treatment after complete resection of gastrointestinal stromal tumors
Zhiliang CHEN ; Hongkun TIAN ; Jianing DING ; Zhiying LI ; Gan MAO ; Yuqiang DU ; Qian SHEN ; Hong ZHOU ; Yong HAN ; Xiangyu ZENG ; Kaixiong TAO ; Peng ZHANG
Chinese Journal of Gastrointestinal Surgery 2024;27(11):1148-1154
Objective:To explore the efficacy of adjusting the dose of imatinib dose in the context of therapeutic drug monitoring (TDM) in patients with gastrointestinal stromal tumors (GISTs) who are receiving adjuvant therapy after complete resection of their tumors.Methods:This was a descriptive study. Inclusion criteria were (1) complete surgical resection with a pathological diagnosis of GIST, (2) postoperative adjuvant therapy with imatinib and dosage adjustment, (3) multiple TDM of imatinib, and (4) complete clinical, pathological, and follow-up data. The data of 70 patients with GISTs treated at Union Hospital, Tongji Medical College, Huazhong University of Science and Technology between January 2015 and December 2023 were collected retrospectively. The study cohort comprised 15 (21.4%) men and 55 (78.6%) women of median age 60 years (range: 25–82). Of the eligible patients, 49 (70.0%) were at high-risk, 14 (20.0%) at intermediate-risk, six (8.6%) at low-risk, and one (1.4%) at very low risk. Patients were followed up by the gastrointestinal stromal tumor clinic every 2–3 months and their plasma concentrations of imatinib were checked. The dose was adjusted to 300 mg/d or 200 mg/d depending on whether they had had ≥ grade III adverse reactions, and whether the first plasma concentration of imatinib was ≥ 1,500 μg/L or between the expected range of 760 μg/L–1,100 μg/L. Studied indicators included adverse reactions, quality of life before and after dose adjustment, and overall survival and recurrence-free survival (RFS) after dose adjustment.Results:Before dose adjustment, all 70 patients received 400 mg of imatinib daily, with initial TDM values of 1,900 ± 568 μg/L, for a median duration of 8.3 months. After dose adjustment, 60 patients received 300 mg daily, with a TDM of 1,216 ± 350 μg/L, whereas 10 received 200 mg daily, with a TDM of 1,023 ± 269 μg/L. The median duration of treatment after dose adjustment was 23.4 months. Compared with those whose dosages were not adjusted, the incidence of bone marrow suppression was significantly lower (74.3% [52/70] vs. 51.4% [36/70], χ 2=9.202, P=0.010); as were the incidences of edema (95.7% [67/70] vs. 50.0% [35/70], χ 2=40.526, P<0.001); skin reactions (70.0% [49/70] vs. 32.9% [23/70), χ 2=22.495, P<0.001); and gastrointestinal reactions (38.6% [27/70] vs. 10.0% [7/70], χ 2=15.899, P<0.001) in those whose dosages were adjusted. The average total scores for physical health before and after dose adjustment were 76 ± 5 and 88 ± 4, respectively; whereas the mental health scores were 75 ± 6 and 89 ± 4, respectively. The median follow-up period was 36 months (range 6–126). During the first 3 years of follow-up, five high-risk patients with non-gastric GISTs developed recurrences. The 3-year overall survival rate was 100%, and the 3-year RFS rate was 92.8%, high-risk patients having a 3-year RFS rate of 89.8%. Conclusion:The adverse reactions and quality of life of GIST patients with severe adverse reactions to adjuvant imatinib therapy after complete resection can be mitigated by appropriately reducing the dosage of imatinib under the guidance of TDM.
8.Analysis of the efficacy of adjusting the dose of imatinib with therapeutic drug monitoring in adjuvant treatment after complete resection of gastrointestinal stromal tumors
Zhiliang CHEN ; Hongkun TIAN ; Jianing DING ; Zhiying LI ; Gan MAO ; Yuqiang DU ; Qian SHEN ; Hong ZHOU ; Yong HAN ; Xiangyu ZENG ; Kaixiong TAO ; Peng ZHANG
Chinese Journal of Gastrointestinal Surgery 2024;27(11):1148-1154
Objective:To explore the efficacy of adjusting the dose of imatinib dose in the context of therapeutic drug monitoring (TDM) in patients with gastrointestinal stromal tumors (GISTs) who are receiving adjuvant therapy after complete resection of their tumors.Methods:This was a descriptive study. Inclusion criteria were (1) complete surgical resection with a pathological diagnosis of GIST, (2) postoperative adjuvant therapy with imatinib and dosage adjustment, (3) multiple TDM of imatinib, and (4) complete clinical, pathological, and follow-up data. The data of 70 patients with GISTs treated at Union Hospital, Tongji Medical College, Huazhong University of Science and Technology between January 2015 and December 2023 were collected retrospectively. The study cohort comprised 15 (21.4%) men and 55 (78.6%) women of median age 60 years (range: 25–82). Of the eligible patients, 49 (70.0%) were at high-risk, 14 (20.0%) at intermediate-risk, six (8.6%) at low-risk, and one (1.4%) at very low risk. Patients were followed up by the gastrointestinal stromal tumor clinic every 2–3 months and their plasma concentrations of imatinib were checked. The dose was adjusted to 300 mg/d or 200 mg/d depending on whether they had had ≥ grade III adverse reactions, and whether the first plasma concentration of imatinib was ≥ 1,500 μg/L or between the expected range of 760 μg/L–1,100 μg/L. Studied indicators included adverse reactions, quality of life before and after dose adjustment, and overall survival and recurrence-free survival (RFS) after dose adjustment.Results:Before dose adjustment, all 70 patients received 400 mg of imatinib daily, with initial TDM values of 1,900 ± 568 μg/L, for a median duration of 8.3 months. After dose adjustment, 60 patients received 300 mg daily, with a TDM of 1,216 ± 350 μg/L, whereas 10 received 200 mg daily, with a TDM of 1,023 ± 269 μg/L. The median duration of treatment after dose adjustment was 23.4 months. Compared with those whose dosages were not adjusted, the incidence of bone marrow suppression was significantly lower (74.3% [52/70] vs. 51.4% [36/70], χ 2=9.202, P=0.010); as were the incidences of edema (95.7% [67/70] vs. 50.0% [35/70], χ 2=40.526, P<0.001); skin reactions (70.0% [49/70] vs. 32.9% [23/70), χ 2=22.495, P<0.001); and gastrointestinal reactions (38.6% [27/70] vs. 10.0% [7/70], χ 2=15.899, P<0.001) in those whose dosages were adjusted. The average total scores for physical health before and after dose adjustment were 76 ± 5 and 88 ± 4, respectively; whereas the mental health scores were 75 ± 6 and 89 ± 4, respectively. The median follow-up period was 36 months (range 6–126). During the first 3 years of follow-up, five high-risk patients with non-gastric GISTs developed recurrences. The 3-year overall survival rate was 100%, and the 3-year RFS rate was 92.8%, high-risk patients having a 3-year RFS rate of 89.8%. Conclusion:The adverse reactions and quality of life of GIST patients with severe adverse reactions to adjuvant imatinib therapy after complete resection can be mitigated by appropriately reducing the dosage of imatinib under the guidance of TDM.
9.A novel CRISPR/Cas9-hLacI donor adapting system for dsDNA-templated gene editing.
Baoxia MA ; Jieyu CUI ; Hongrun QIAN ; Xiaojun ZHANG ; Sen YANG ; Qijing ZHANG ; Yifan HAN ; Zhiying ZHANG ; Jiangang WANG ; Kun XU
Chinese Journal of Biotechnology 2023;39(10):4204-4218
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.
Humans
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Animals
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Gene Editing
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CRISPR-Cas Systems/genetics*
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HEK293 Cells
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Homologous Recombination
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DNA
10.A high-efficiency and versatile CRISPR/Cas9-mediated HDR-based biallelic editing system.
Xinyi LI ; Bing SUN ; Hongrun QIAN ; Jinrong MA ; Magdalena PAOLINO ; Zhiying ZHANG
Journal of Zhejiang University. Science. B 2022;23(2):141-152
Clustered regulatory interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 nuclease (Cas9), the third-generation genome editing tool, has been favored because of its high efficiency and clear system composition. In this technology, the introduced double-strand breaks (DSBs) are mainly repaired by non-homologous end joining (NHEJ) or homology-directed repair (HDR) pathways. The high-fidelity HDR pathway is used for genome modification, which can introduce artificially controllable insertions, deletions, or substitutions carried by the donor templates. Although high-level knock-out can be easily achieved by NHEJ, accurate HDR-mediated knock-in remains a technical challenge. In most circumstances, although both alleles are broken by endonucleases, only one can be repaired by HDR, and the other one is usually recombined by NHEJ. For gene function studies or disease model establishment, biallelic editing to generate homozygous cell lines and homozygotes is needed to ensure consistent phenotypes. Thus, there is an urgent need for an efficient biallelic editing system. Here, we developed three pairs of integrated selection systems, where each of the two selection cassettes contained one drug-screening gene and one fluorescent marker. Flanked by homologous arms containing the mutated sequences, the selection cassettes were integrated into the target site, mediated by CRISPR/Cas9-induced HDR. Positively targeted cell clones were massively enriched by fluorescent microscopy after screening for drug resistance. We tested this novel method on the amyloid precursor protein (APP) and presenilin 1 (PSEN1) loci and demonstrated up to 82.0% biallelic editing efficiency after optimization. Our results indicate that this strategy can provide a new efficient approach for biallelic editing and lay a foundation for establishment of an easier and more efficient disease model.
Alleles
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CRISPR-Cas Systems
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DNA End-Joining Repair
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Gene Editing/methods*
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Recombinational DNA Repair

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