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.

Macrophage MED1 deficiency promotes the development of atherosclerosis in female ApoE and LDLR knockout mice / 西安交通大学学报(医学版)

【Objective】 To study the effect of macrophage mediator 1 (MED1) deficiency on atherosclerosis in female mice. 【Methods】 ApoE knockout (ApoE-/-), LDLR knockout (LDLR-/-), MED1fl/fl, and macrophage MED1 knockout (MED1△Mac) mice were recruited in the study. Two types of mouse model were constructed:ApoE and macrophage MED1 double knockout (MED1△Mac/ApoE-/-) mice and their littermate controls (MED1fl/fl/ApoE-/-). ② LDLR knockout (LDLR-/-) mice receiving bone marrow from MED1△Mac (MED1△Mac→LDLR-/-) or MED1fl/fl (MED1fl/fl→LDLR-/-) mice. Female mice from these two models were fed a Western diet (21% fat and 0.15% cholesterol) for 12 weeks to promote the development of atherosclerosis. Body weight, total cholesterol (TC), and total triglyceride (TG) content in plasma were measured dynamically. After Western diet feeding for 12 weeks, aortic tree and aortic root were collected and hematoxylin-eosin (H&E) and oil red O staining were performed. 【Results】 Plasma TC and TG did not significantly differ between MED1fl/fl/ApoE-/- control group and MED1△Mac/ApoE-/-experimental group. However, the plaque area in aortic tree and aortic root was significantly increased in MED1△Mac/ApoE-/-mice. Moreover, compared with that in MED1fl/fl→LDLR-/- control group, the plaque area of aortic tree and aortic root had an increasing trend in MED1△Mac→LDLR-/- mice group. 【Conclusion】 MED1 deficiency in macrophages promotes the development of atherosclerosis in female ApoE or LDLR knockout mice.

Effect of intestinal Metrnl gene knockout on intestinal microbiota and ulcerative colitis / 药学实践杂志

Objective To investigate the effect of intestinal Metrnl on dextran sodium sulfate (DSS)-induced ulcerative colitis mouse model and the regulation mechanism of intestinal microbiota. Methods Different concentrations of DSS (3% DSS and 1% DSS) were used to induce ulcerative colitis on C57 mice to determine the experimental conditions. Intestinal epithelial Metrnl specific knockout mice (Metrnl(-/-)) and its control mice (Metrnl(+/+)) were administrated with 3% DSS for 5 d. Then the survival time, body weight, DAI (disease activity index), colon length and pathological changes in colon tissues were observed. 16S ribosomal RNA gene sequencing was used to detect the composition of intestinal microbiota. Results Compared with 1% DSS, 3% DSS could significantly aggravate ulcerative colitis on C57 mice, such as lower survival rate (P<0.05), more weight loss (P<0.05), higher DAI score (P<0.05), shorter colon length (P<0.05) and higher pathology score (P<0.05). After administrated to 3% DSS for 5 d, comparing with Metrnl(+/+) mice, Metrnl(-/-) mice showed more weight loss (P<0.05), higher DAI score (P<0.05), shorter colon length (P<0.05) and higher pathology score (P<0.05). The 16S ribosomal RNA results showed that the diversity of intestinal microbiota in Metrnl(-/-) mice significantly decreased. Furthermore, Bacteroidetes and Proteobacteria significantly decreased, while Firmicutes increased. Conclusion Metrnl could protect the DSS-induced ulcerative colitis mouse through regulating intestinal microbiota.

Effect of ACE2 deletion on vasoconstriction reactivity of aortic segments in mice with tourniquet shock / 中国病理生理杂志

AIM:To observe the effect of angiotensin-converting enzyme 2(ACE2)deletion on vasoconstric-tion reactivity of aortic segments in ACE2 knockout(KO)mice with tourniquet shock(TS).METHODS:The 8-month-old male mice with C57BL/6 background were divided into wild-type(WT)control group,WT-TS group,KO group and KO-TS group,with 10 mice in each group,of which five were used for determination of vascular reactivity,and the other five for the other assays.The hindlimbs of the mice in WT-TS group and KO-TS group were ligated with tourniquet for 2 h and loosened for 4 h.The mice in WT group and KO group were subjected to the same treatment except for tourniquet liga-tion.The vasoconstriction reactivity of the aorta was measured on tensiometer.The morphological damage of the aorta was evaluated by vascular histopathology.Western blot was used to detect the expression of AT1,MAS,ACE and ACE2 pro-teins in aorta.The serum levels of angiotensin(Ang)Ⅱ and Ang-(1-7)were determined by enzyme-linked immunosorbent assay.RESULTS:Compared with WT group,the mice in WT-TS group had lower vascular reactivity to norepinephrine(NE)and obvious vascular lesions.The expression of ACE protein increased significantly(P＜0.01),while the expres-sion of ACE2 decreased(P＜0.05).The expression of AT1 protein in aorta decreased significantly,the expression of MAS protein increased significantly,and the AT1/MAS ratio decreased(P＜0.01).Serum Ang II level increased,serum Ang-(1-7)level decreased,and Ang Ⅱ/Ang-(1-7)ratio increased(P＜0.05).Compared with WT group,vascular reactivity in KO group increased at low concentration of NE(＜10-7 mol/L),and decreased at high concentration(＞10-7 mol/L)without vascular lesion.The expression levels of aortic AT1,MAS and ACE were all elevated(P＜0.05).The serum level of Ang Ⅱ increased(P＜0.05),but the level of Ang-(1-7)had no obvious change.Compared with KO and WT-TS groups,the aortic reactivity in KO-TS group subtracted apparently(P＜0.05),representing its curve shifting to the right obviously.The morphological damage aggravated slightly,and the expression of AT1 and ACE increased slightly in KO-TS group com-pared with WT-TS group(P＜0.05).However,the expression of MAS increased significantly in vascular tissue(P＜0.01).The serum levels of Ang Ⅱ and Ang-(1-7)further increased and decreased,respectively,and the Ang Ⅱ/Ang-(1-7)ratio increased(P＜0.01).CONCLUSION:Deficiency of ACE2 induces severe aortic hyporeactivity to NE during TS,which may be related to the increased imbalance of renin-angiotensin system in ACE2 gene knockout mice.

Establishment of lens opacity model in Grx2 knockout mice based on CRISPR/cas9 system and the role of Grx2 in the pathogenesis of cataract / 中华实验眼科杂志

Objective:To explore the role of Grx2 in the pathogenesis of cataract by establishing Grx2 knockout (KO) and knockin (KI) mouse models. Methods:Ten black C57BL/6J mice were selected to make Grx2 KO model ( n=5) and Grx2 KI model ( n=5) using CRISPR/Cas9 system.The offspring mice were sequenced by tail clipping and included in the corresponding experimental group according to the genotype.The general condition and lens opacity was recorded.After the mice were sacrificed, the pathological changes of lens were observed by hematoxylin-eosin staining.The contents of reactive oxygen species (ROS) and 8-hydroxy-desoxyguanosine (8-OHdG) were analyzed by enzyme-linked immunosorbent assay (ELISA).The relative expression levels of Grx2, glutathione (GSH), B-cell lymphoma-2 (Bcl-2) , glutathione disulfide (GSSG) and Bcl-2-associated X protein (Bax) in mice lens were assayed.The use and feeding of experimental animals were in accordance with the Regulations on the Management of Experimental Animals issued by the State Science and Technology Commission.The study protocol was approved by the Ethics Committee of the Second Affiliated Hospital of Chongqing Medical University (No.2020-125). Results:The offspring of Grx2 KO and Grx2 KI homozygous and heterozygous mice were confirmed by tail cutting nested PCR and gene sequencing.Compared with the wild type (WT) mice of same age, the lens opacity of Grx2 KO heterozygous mice occurred earlier, while the lens of Grx2 KI homozygous mice remained transparent all the time.A large number of gaps and vacuoles were found in the lens fibers of 5-month-old Grx2 KO mice.The 8-OHdG content and ROS fluorescence intensity in the lens of 5-month-old Grx2 KO mice were (3.886±0.326)ng/ml and 1 594±132, which were significantly higher than (3.531±0.250)ng/ml and 1 157±123 in WT mice ( t=2.711, P=0.033; t=3.384, P=0.028).The relative expression levels of Grx2, GSH and Bcl-2 in the lens of 5-month-old Grx2 KO mice were 0.23±0.01, 0.70±0.06 and 0.32±0.03, which were significantly lower than 0.52±0.02, 1.04±0.08 and 0.49±0.04 of WT mice ( t=2.815, P=0.020; t=2.457, P=0.033; t=2.279, P=0.041). Conclusions:Grx2 KO and Grx2 KI mouse models are successfully established in this study.The occurrence and development of age-related cataract are accelerated in Grx2 KO mice.

Effects of Bcl3 gene knockout on composition of spleen immune cells and antitumor ability of mice / 中华微生物学和免疫学杂志

Objective:To investigate the effects of Bcl3 gene knockout on the composition of spleen immune cells and antitumor ability of mice.Methods:Bcl3 gene knockout mice (Bcl3 -/-) were established by CRISPR/Cas9 genome editing technology. Blood routine test and flow cytometry were used to detect the immune cell composition in Bcl3 -/- mice. Lung metastasis models were established by injecting mice with B16F10 melanoma cells. The number of tumor nodules in lung and the survival time of mice were used to assess the antitumor ability of wild-type (WT) and Bcl3 -/- mice. Results:Bcl3 -/- mice were successfully bred to a strain with normal growth rate and normal breeding performance. Furthermore, no embryonic death occurred. Compared with WT mice, Bcl3 -/- mice showed splenomegaly and a significant increase in the number of spleen immune cells ( P<0.05). The counts and percentages of platelets and neutrophils in Bcl3 -/- mice were significantly lower than those in WT mice. The proportion of CD19 + B cells showed no significant change, while the proportions of CD3 + T cells and T cell subsets (CD4 + , CD8 + , Treg) increased significantly ( P<0.05). The proportions of NK cells (NK1.1 + ) and neutrophils (Gr1 + ) decreased ( P<0.05), while no significant change in the proportion of DC (CD11b + ) was observed. There were a large number of tumor nodules formed by melanoma cells in the lung of Bcl3 -/- tumor bearing mice, and their survival time was shortened dramatically. Conclusions:Knockout of Bcl3 gene affected the development, differentiation and function of immune cells, thereby reducing the antitumor ability of mice.

Effect of Ethyl Acetate Extract of Acanthopanacis Senticosi Radix et Rhizoma seu Caulis on Intestinal Flora in ApoE-/- Mice with Atherosclerosis / 中国实验方剂学杂志

ObjectiveTo observe the effect of ethyl acetate extract of Acanthopanacis Senticosi Radix et Rhizoma seu Caulis on high-fat diet-induced apolipoprotein E gene knockout （ApoE-/-） mice， and explore its mechanism of treating atherosclerosis by regulating intestinal flora. MethodThirty-two 8-week-old male ApoE-/- mice were randomly divided into model group， rosuvastatin group （10 mg·kg-1）， high-， low-dose groups of ethyl acetate extract of Acanthopanacis Senticosi Radix et Rhizoma seu Caulis （75， 25 mg·kg-1）， with 8 mice in each group. Eight C57BL/6 mice were used as blank group. After 8 weeks of continuous administration， blood was taken to determine the blood lipid level. Enzyme-linked immunosorbent assay （ELISA） was used to detect the contents of related indexes in serum of mice. Hematoxylin-eosin （HE） staining was used to observe the formation of aortic plaque in mice. Cecal contents were collected and 16S rRNA amplicon sequencing was used to detect intestinal flora. ResultCompared with the blank group， the plaque area of the model group was significantly increased with inflammatory infiltration， the contents of triglyceride （TG）， total cholesterol （TC）， low-density lipoprotein cholesterol （LDL-C）， inflammatory factors and inducible nitric oxide synthase （iNOS） were increased， while the content of high-density lipoprotein cholesterol （HDL-C） was decreased. Compared with the model group， rosuvastatin group and high- and low-dose groups of ethyl acetate extract of Acanthopanacis Senticosi Radix et Rhizoma seu Caulis could improve the deposition of aortic plaque， reduce the contents of TG， TC， LDL-C， inflammatory factors and iNOS， and increase the content of HDL-C. Compared with the blank group， the relative abundances of Firmicutes and Proteobacteria in the model group increased， while the relative abundance of Bacteroidetes decreased. Alpha and Beta diversity analysis showed that samples of each group could be significantly isolated， and the total number and abundance of intestinal flora species in the model group were low. Compared with the model group， ethyl acetate extract of Acanthopanacis Senticosi Radix et Rhizoma seu Caulis could increase the relative abundance of beneficial bacteria and decrease the relative abundance of pathogenic bacteria. ConclusionEthyl acetate extract of Acanthopanacis Senticosi Radix et Rhizoma seu Caulis was mainly composed of flavonoids， which can treat atherosclerosis by regulating the intestinal flora and improve the pathological changes in the aorta of ApoE-/- mice induced by high-fat diet. The mechanism may be related to its ability to reduce the level of inflammatory factors， improve antioxidant capacity and repair the disorder of intestinal flora structure.

Knockout of farnesoid X receptor gene aggravates cisplatin-induced kidney injury / 中南大学学报(医学版)

OBJECTIVES@#Farnesoid X receptor (FXR) is a member of the nuclear receptor superfamily of ligand activated transcription factors and belongs to bile acid receptor. Studies have shown that the expression of FXR in renal tissue can reduce renal injury via regulation of glucose and lipid metabolism, inhibition of inflammatory response, reduction of oxidative stress and renal fibrosis. However, it is unclear whether FXR is involved in autophagy in renal diseases. This study aims to investigate the role of FXR in cisplatin-induced acute renal injury and whether its mechanism is related to autophagy regulation.@*METHODS@#Twelve male WT or FXR-KO mice at 12 weeks were randomly divided into a WT group, a WT+cisplatin group, a FXR-KO group, and a FXR-KO+cisplatin group, with 6 mice in each group. The WT+cisplatin group and the FXR-KO+cisplatin group were intraperitoneally injected with cisplatin (20 mg/kg), and the WT group and the FXR-KO group were intraperitoneally injected with equal volume of cisplatin solvent. Seventy-two hours later, the mice were killed and blood and renal tissue samples were collected. The levels of SCr and BUN were detected by immunoturbidimetry. After the staining, the pathological changes of renal tissue were observed under optical microscope. The protein levels of LC3 and p62 were detected by Western blotting and immunohistochemistry. The clearance of damaged mitochondria and the accumulation of lysosomal substrate were observed under electron microscope. The apoptosis of renal tubular epithelial cells was detected by TUNEL.@*RESULTS@#Compared with the WT group or the FXR-KO group, both SCr and BUN levels in the WT+cisplatin group or the FXR-KO+cisplatin group were significantly increased (P<0.01 or P<0.001), and SCr and BUN levels in the FXR-KO+cisplatin group were significantly higher than those in the WT+cisplatin group (both P<0.05). Under the light microscope, there were no obvious pathological changes in the renal tissue of mice in the WT group and the FXR-KO group. Both the WT+cisplatin group and the FXR-KO+cisplatin group had vacuolar or granular degeneration of renal tubular epithelial cells, flat cells, lumen expansion, brush edge falling off, and even exposed basement membrane and tubular formation. The scores of renal tubular injury in the WT+cisplatin group and the FXR-KO+cisplatin group were significantly higher than those in the WT group and the FXR-KO group, respectively (both P<0.001), and the score in the FXR-KO+cisplatin group was significantly higher than that in the WT+cisplatin group (P<0.05). Under the transmission electron microscope, the mitochondria of mouse tubular epithelial cell in the WT+cisplatin group and the FXR-KO+cisplatin group was swollen, round, vacuolated, cristae broken or disappeared; the lysosome was uneven and high-density clumps, and the change was more obvious in the FXR-KO+cisplatin group. Western blotting showed that the ratio of LC3-II to LC3-I was decreased and the expression of p62 was increased in the WT+cisplatin group compared with the WT group and the FXR-KO+cisplatin group compared with FXR-KO group (P<0.05 or P<0.01); compared with the FXR-KO group, the ratio of LC3-II to LC3-I was decreased and the expression of p62 was increased significantly in the FXR-KO+cisplatin group (both P<0.05). Immunohistochemistry results showed that the expression of total LC3 and p62 in renal cortex of the WT+cisplatin group and the FXR-KO+cisplatin group was increased significantly, especially in the FXR-KO+cisplatin group. TUNEL results showed that the mice in the WT group and the FXR-KO group had negative staining or only a few apoptotic tubular epithelial cells, and the number of apoptotic cells in the WT+cisplatin group and the FXR-KO+cisplatin group were increased. The apoptosis rates of renal tubular epithelial cells in the WT+cisplatin group and the FXR-KO+cisplatin group were significantly higher than those in the WT group and the FXR-KO group, respectively (both P<0.001), and the apoptosis rate in the FXR-KO+cisplatin group was significantly higher than that in the WT+cisplatin group (P<0.05).@*CONCLUSIONS@#Knockout of FXR gene aggravates cisplatin induced acute renal injury, and its mechanism may be related to inhibiting autophagy and promoting apoptosis.

Effects of deleting peptidoglycan hydrolase genes on the viable cell counts of Bacillus amyloliquefaciens and the yield of alkaline protease / 生物工程学报

In order to explore the effect of peptidoglycan hydrolase on the viable cell counts of Bacillus amyloliquefaciens and the yield of alkaline protease, five peptidoglycan hydrolase genes (lytC, lytD, lytE, lytF and lytG) of B. amyloliquefaciens TCCC111018 were knocked out individually. The viable cell counts of the bacteria and their alkaline protease activities before and after gene deletion were determined. The viable cell counts of the knockout mutants BA ΔlytC and BA ΔlytE achieved 1.67×106 CFU/mL and 1.44×106 CFU/mL respectively after cultivation for 60 h, which were 32.5% and 14.3% higher than that of the control strain BA Δupp. Their alkaline protease activities reached 20 264 U/mL and 17 265 U/mL, respectively, which were 43.1% and 27.3% higher than that of the control strain. The results showed that deleting some of the peptidoglycan hydrolase genes effectively maintained the viable cell counts of bacteria and increased the activity of extracellular enzymes, which may provide a new idea for optimization of the microbial host for production of industrial enzymes.

Generation of genetic modified pigs devoid of GGTA1 and expressing the human leukocyte antigen-G5 / 生物工程学报

Pigs are considered as ideal donors for xenotransplantation because they have many physiological and anatomical characteristics similar to human beings. However, antibody-mediated immunity, which includes both natural and induced antibody responses, is a major challenge for the success of pig-to-primate xenotransplantation. Various genetic modification methods help to tailor pigs to be appropriate donors for xenotransplantation. In this study, we applied transcription activator-like effector nuclease (TALEN) to knock out the porcine α-1, 3-galactosyltransferase gene GGTA1, which encodes Gal epitopes that induce hyperacute immune rejection in pig-to-human xenotransplantation. Meanwhile, human leukocyte antigen-G5 gene HLA-G5, which acts as an immunosuppressive factor, was co-transfected with TALEN into porcine fetal fibroblasts. The cell colonies of GGTA1 biallelic knockout with positive transgene for HLA-G5 were chosen as nuclear donors to generate genetic modified piglets through a single round of somatic cell nuclear transfer. As a result, we successfully obtained 20 modified piglets that were positive for GGTA1 knockout (GTKO) and half of them expressed the HLA-G5 protein. Gal epitopes on the cell membrane of GTKO/HLA-G5 piglets were completely absent. Western blotting and immunofluorescence showed that HLA-G5 was expressed in the modified piglets. Functionally, the fibroblasts from the GTKO/HLA-G5 piglets showed enhanced resistance to complement-mediated lysis ability compared with those from GTKO-only or wild-type pigs. These results indicate that the GTKO/HLA-G5 pigs could be a valuable donor model to facilitate laboratory studies and clinics for xenotransplantation.

Construction of a stable TrxR1 knockout HCT-116 cell line using CRISPR/Cas9 gene editing system / 生物工程学报

To investigate the cellular target selectivity of small molecules targeting thioredoxin reductase 1, we reported the construction and functional research of a stable TrxR1 gene (encode thioredoxin reductase 1) knockout HCT-116 cell line. We designed and selected TrxR1 knockout sites according to the TrxR1 gene sequence and CRISPR/Cas9 target designing principles. SgRNA oligos based on the selected TrxR1 knockout sites were obtained. Next, we constructed knockout plasmid by cloning the sgRNA into the pCasCMV-Puro-U6 vector. After transfection of the plasmid into HCT-116 cells, TrxR1 knockout HCT-116 cells were selected using puromycin resistance. The TrxR1 knockout efficiency was identified and verified by DNA sequencing, immunoblotting, TRFS-green fluorescent probe, and cellular TrxR1 enzyme activity detection. Finally, the correlation between TrxR1 expression and cellular effects of drugs specifically targeting TrxR1 was investigated by CCK-8 assay. The results demonstrated that the knockout plasmid expressing the sgRNA effectively knocked-out TrxR1 gene within HCT-116 cells, and no expression of TrxR1 protein could be observed in stable TrxR1 knockout HCT-116 (HCT116-TrxR1-KO) cells. The TrxR1-targeting inhibitor auranofin did not show any inhibitory activity against either cellular TrxR1 enzyme activity or cell proliferation. Based on these results, we conclude that a stable TrxR1 gene knockout HCT-116 cell line was obtained through CRISPR/Cas9 techniques, which may facilitate investigating the role of TrxR1 in various diseases.

Establishment and identification of a human megakaryocytic cell line with low Ley expression / 中国输血杂志

【Objective】 To establish a stable human megakaryocytic cell line with low expression of Ley antigen to further study the role of Ley on activation of platelets. 【Methods】 The expression level of the Ley antigen in a human megakaryocytic cell line, DAMI, was determined using Western Blot and flow cytometry. The expression level of genes that encode fucosyltransferase (FUTs), which was involved in the biosynthesis of Ley antigen, was also determined to identify the candidate genes to be knocked out. The candidate FUT gene was knocked out via a CRISPR/Cas 9 gene knockout system and cells with low Ley antigen expression were sorted by flow cytometry. The sorted cell line was cultured and characterized. 【Results】 The Ley was expressed intensively on DAMI cell. FUT1 and FUT4 mRNA was expressed relatively higher, both may be key enzymes for the biosynthesis of the Ley antigen. In the DAMI cell line with the knockout of FUT1 gene, the expression of the Ley adntigen was remarkedly reduced, while cell proliferation was not affected compared to the wildtype control cells. 【Conclusions】 Since various FUTs contributes to the biosynthesis of the Ley antigen, the knockout of the primary one of them cannot totally block its biosynthesis, but only reduce its expression. In this study, a stable FUT gene knockout human megakaryocyticcell line is established using CRISPR/Cas 9 technology, which provides basis for the study of the impact of the Ley antigen on platelet functions.

Effects of brain-specific knockout of Sirt6 gene on cerebral cortex in aged mice / 中华行为医学与脑科学杂志

Objective:To study the effect of senescence gene silent information regulator 6 (Sirt6) knockout on the brain of aged mice.Methods:Sirt6-flox transgenic mice were constructed, and the mouse brain tissue was specifically knocked out by Emx1-Cre tool mice.According to genotyping, 11 wild-type mice were selected as control group(WT group) and 10 Sirt6 gene konckout mice were selected as conditional knockout group(cKO group). Body size and body weight of the aged mice were measured and cerebral cortex thickness was measured by HE staining.Brain neurogenesis was analyzed with EdU markers.The expression of RNA-binding protein HuR and apoptosis-related protein Caspase-3 were detected by Western blot.Meanwhile, histone acetylation levels in the cortex were detected.Results:Sirt6 brain tissue-specific knocked out mice were successfully constructed.Compared with the brain tissue area((2.07±0.22) cm 2)and cortical thickness ((970.56±80.91) μm) of WT mice in the 12-month-old group, the brain tissue area ((1.61±0.14)cm 2) and cortical thickness ((822.88±53.94) μm) in Sirt6 cKO group were smaller, and the differences were statistically significant (both P<0.05). EdU incorporation into nerve cells showed that the number of EdU incorporation into periventricular nerve cells in cKO group was lower ((4.75±1.48)) than that in WT group ((10.29±1.93)). The difference was statistically significant ( P<0.001). In the experiment of 17 months age group, mice in cKO group were smaller in body size, lower in body weight ((29.00±1.08) g) and smaller in brain area ((1.54±0.55)cm 2)compared with WT group in body size, body weight ((35.25±4.17) g) and brain tissue area ((1.98±0.18) cm 2)(both P<0.05). The expression of Caspase-3 and HuR in cortical proteins of these two age groups decreased( t=2.95, 5.38, both P<0.05), and the expression of H3K9ac and H3K56ac increased( t=3.53, 2.78, both P<0.05), but the expression of Sirt1 homologous gene remained unchanged( t=1.26, P>0.05). Conclusion:The specific deletion of Sirt6 in brain tissue can lead to the decrease of brain neurogenesis in aged mice, and the aggravation of aging and the increase of apoptosis, which may be the reason for the thinning of cerebral cortex and brain tissue atrophy.The molecular mechanism is speculated to be related to the increase of acetylation level after Sirt6 knockout

Expressions of cytokeratin 14 and proliferating cell nuclear antigen in the Hertwig's epithelial root sheath of a Vps4b knockout mouse / 华西口腔医学杂志

OBJECTIVES@#The effect of Vps4b gene mutation on the expressions of cytokeratin 14 (CK14) and proliferating cell nuclear antigen (PCNA) in the Hertwig's epithelial root sheath (HERS) is investigated.@*METHODS@#The bilateral mandibular tissues of mouse on postnatal days 5, 9, 11, 15, and 19 were removed. The mandibular first molar tissue sections were obtained after paraffin embedding. The CK14 and PCNA expressions in the epithelial root sheath of the normal mouse and Vps4b knockout mouse were compared through immunohistochemistry.@*RESULTS@#On postnatal day 5, the normal mouse began to form HERS and had a strong positive PCNA expression in the HERS cells; on postnatal day 9, the HERS structure was continuous, and PCNA was positive in the HERS cells; on postnatal day 11, a small portion of HERS began to break, and PCNA was weakly positive in the HERS cells; on postnatal day 15, HERS continued to fracture; PCNA was weakly and positively expressed in the HERS cells on the root surface; on postnatal day 19, the tooth root reached normal physiological length, and PCNA was positively expressed in the HERS cells of the terminal part. Similar to the normal mouse, the gene knockout mouse also formed a HERS structure on postnatal day 5. However, HERS began to break on postnatal day 9. On postnatal day 19, only a few fragments of HERS were found on the root surface, and the root development was immature. Moreover, the expression intensity of PCNA in the gene knockout mouse was decreased.@*CONCLUSIONS@#The Vps4b gene mutation may change the CK14 and PCNA expressions, leading to abnormal root development.

Knockout fth1b affects early mineralization of zebrafish pharyngeal teeth / 华西口腔医学杂志

OBJECTIVES@#A study was conducted to explore the expression pattern and function of ferritin heavy polypeptide gene (fth1b) in zebrafish pharyngeal teeth development and lay the foundation for subsequent research on teeth development and mineralization.@*METHODS@#The zebrafish embryos were harvested at 56, 72, 96, and 120 h after fertilization. The expression of fth1b in zebrafish pharyngeal teeth development was detected by whole embryo @*RESULTS@#The expression pattern of fth1b gene was very similar to that of the known zebrafish pharyngeal teeth marker dlx2b and was specifically expressed in the zebrafish pharyngeal teeth during development. After the specific knockout of the gene fth1b, the earliest gene that can be detect in zebrafish pharyngeal teeth-pitx2 was expressed normally during early development. The dlx2b expression was not significantly different from that of wild type zebrafish, but the mineralization of pharyngeal teeth in the mutant was weaker than that of wild type zebrafish.@*CONCLUSIONS@#The gene fth1b is specifically expressed in zebrafish pharyngeal teeth and acts on their early mineralization.

The effects of casein kinase 2 interacting protein-1 on the growth and development of craniomaxillofacial soft and hard tissues in mice / 口腔疾病防治

Objective@# To investigate the effect of casein kinase 2 interacting protein-1 (CKIP-1) on craniofacial soft tissues and hard tissues, to provide the basis for the study and treatment of craniomaxillofacial related diseases.@*Methods@#6-month- old male CKIP-1 knockout (KO) mice were selected as the experimental group, and wild-type (WT) mice were selected as the control group. The craniomaxillofacial hard tissues (parietal bone, nasal bone, incisors and molars) were analyzed through micro- CT, and the morphological changes of maxillofacial soft tissues (nasal cartilage, lip mucosa and tongue) were analyzed through HE staining and toluidine blue staining.@* Results@#CKIP-1 negatively regulated bone mass of cancellous bone of cranial and maxillofacial bones and dentin mineralization. Compared with the WT mice, the thickness of the parietal baffle layer increased by 93% in KO mice, while cortical bone showed no significant difference between the two groups. The nasal cancellous bone thickness increased by 160% in KO-mice, while cortical bone showed no significant difference between the two groups; the enamel thickness was normal, but the pulp cavity became smaller and the dentin thickness increased by 48%. Compared with the WT mice, the HE staining and toluidine blue staining analyses of the soft tissues revealed that the thickness of the alar cartilage plate of KO mice increased by 57%, and local ossification was found within the cartilage plate. The thickness of the keratinized layer of the labial mucosa increased by 170% in KO mice and the muscle fiber diameter of the lingual muscle increased by 45%. @*Conclusion@#CKIP-1 genes have different effects on the growth and development of various soft and hard tissues in the maxillofacial region of mice.

Application of CRISPR/Cas9 lentiviral vector in construction of rat hepatic stellate cells with COX-2 gene knockout / 临床肝胆病杂志

ObjectiveTo obtain HSC-T6 cells with stable expression of Cas9 protein and HSC-T6-COX-2-/- cells with COX-2 gene defect by transfecting HSC-T6 cells with CRISPR/Cas9 lentiviral vector, and to provide a good method for further functional research and new strategies for the clinical treatment of liver fibrosis. MethodsThe COX-2 gene-specific sgRNAs (COX-2-sgRNA-1, COX-2-sgRNA-2, COX-2-sgRNA-3) were designed, synthesized, and connected to the GV371 vector, and the recombinant plasmid and the packaging plasmid were transfected into 293T cells to form lentivirus particles; the fluorescence method was used to measure virus titer. The most appropriate amount of the virus was calculated based on MOI. Lenti-Cas9-puro was transfected into HSC-T6 cells, and HSC-T6-Cas9 cells were screened out by puromycin; Lenti-COX-2-sgRNA-EGFP was transfected into HSC-T6-Cas9 cells to obtain HSC-T6-COX-2-/- cells. Cruiser enzyme digestion and Western blot were used to verify gene knockout at the gene and protein levels. An analysis of variance was used for comparison of continuous data between multiple groups, and the least significant difference t-test was used for further comparison between two groups. ResultsSequencing verified that the COX-2-sgRNA expression vector was constructed successfully. Recombinant expression plasmids and packaging plasmids were transfected into 293T cells to form lentivirus particles, and the fluorescence method showed a virus titer of ＞1×108. HSC-T6 cells with stable expression of Cas9 protein and HSC-T6-COX-2-/- cells with COX-2 gene defect were successfully constructed. The HSC-T6-Cas9 group had significantly higher relative mRNA expression of LV-Cas9-Puro than the CON group (541.93±105.76 vs 1.00±0.02, t=12.995, P＜0.01). Cruiser enzyme digestion and Western blot showed that the CRISPR/Cas9 lentivirus expression vectors played a role in the target, among which COX-2-sgRNA-2 knockout had the most significant effect, and this group had a significant reduction in the protein expression level of COX-2 compared with the CON group and the NC group (both P＜0.05), suggesting that COX-2-sgRNA was active. ConclusionA CRISPR/Cas9 lentivirus vector is successfully constructed for COX-2 target gene, and HSC-T6-COX-2-/- cells with stable COX-2 gene knockout are obtained.

Pathogenic role of NDUFA13 inactivation in spontaneous hepatitis in mice and the mechanism / 南方医科大学学报

OBJECTIVE@#To investigate the role of NDUFA13 inactivation in the pathogenesis of spontaneous hepatitis in mice and explore the possible mechanisms.@*METHODS@#Hepatocyte-specific NDUFA13 knockout (NDUFA13@*RESULTS@#Liver-specific NDUFA13 heterozygous knockout mice were successfully constructed as verified by PCR results. HE staining revealed severe liver damage in both 4- week-old and 2-year-old NDUFA13@*CONCLUSIONS@#Hepatocytes-specific NDUFA13 ablation can trigger spontaneous hepatitis in mice possibly mediated by the activation of ROS/NF-κB/NLRP3 signaling.

Rapid screening of single guide RNA targeting pig genome and the harvesting of monoclonal cells by microarray seal / 生物医学工程学杂志

The emergence of regular short repetitive palindromic sequence clusters (CRISPR) and CRISPR- associated proteins 9 (Cas9) gene editing technology has greatly promoted the wide application of genetically modified pigs. Efficient single guide RNA (sgRNA) is the key to the success of gene editing using CRISPR/Cas9 technology. For large animals with a long reproductive cycle, such as pigs, it is necessary to screen out efficient sgRNA

Ferulate 5-hydroxylase gene (F5H) regulation of glycyrrhizic acid biosynthesis determined by gene overexpression and knockout / 药学学报

Ferulate 5-hydroxylase (F5H) is a key enzyme involved in the phenylpropane metabolism pathway. Based on our previous transcriptome sequencing study, F5H played a negative regulatory role in glycyrrhizic acid (GA) biosynthesis. Therefore, in this study we cloned the F5H gene and investigated its regulatory effect on GA accumulation through gene overexpression and knockout. F5H was cloned from Glycyrrhiza glabra L. (GenBank Accession No. MK882511). A plant binary expression vector pCA-F5H was constructed by inserting F5H into pCAMBIA1305.1 at Spe I and Bgl II sites. The sgRNA sequences were designed based on the first exon of F5H. The CRISPR/Cas9 gene editing vector pHSE-F5H was constructed by inserting F5H sgRNA into pHSE401 at two Bsa Ⅰ sites. PCA-F5H and pHSE-F5H were transfected into Agrobacterium tumefaciens ATCC15834, which was used to induce hairy root overexpressing or knocking out F5H with licorice hypocotyl as explants. At the same time, wild type and negative control hairy roots were also generated. UPLC was used to assay the GA content in different hairy root lines, and results showed that the GA content in hairy root lines knocking out F5H was significantly higher, whereas in hairy root lines overexpressing F5H GA content was lower than that in the wild-type and negative control. In this work, through a reverse genetics strategy, the negative regulatory effect of F5H on GA biosynthesis was confirmed through gene overexpression and knockout. This work will lay a foundation for further elucidation of the molecular regulatory network of GA biosynthesis.