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Since it was first recognized in bacteria and archaea as a mechanism for innate viral immunity in the early 2010s, clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein (Cas) has rapidly been developed into a robust, multifunctional genome editing tool with many uses. Following the discovery of the initial CRISPR/Cas-based system, the technology has been advanced to facilitate a multitude of different functions. These include development as a base editor, prime editor, epigenetic editor, and CRISPR interference (CRISPRi) and CRISPR activator (CRISPRa) gene regulators. It can also be used for chromatin and RNA targeting and imaging. Its applications have proved revolutionary across numerous biological fields, especially in biomedical and agricultural improvement. As a diagnostic tool, CRISPR has been developed to aid the detection and screening of both human and plant diseases, and has even been applied during the current coronavirus disease 2019 (COVID-19) pandemic. CRISPR/Cas is also being trialed as a new form of gene therapy for treating various human diseases, including cancers, and has aided drug development. In terms of agricultural breeding, precise targeting of biological pathways via CRISPR/Cas has been key to regulating molecular biosynthesis and allowing modification of proteins, starch, oil, and other functional components for crop improvement. Adding to this, CRISPR/Cas has been shown capable of significantly enhancing both plant tolerance to environmental stresses and overall crop yield via the targeting of various agronomically important gene regulators. Looking to the future, increasing the efficiency and precision of CRISPR/Cas delivery systems and limiting off-target activity are two major challenges for wider application of the technology. This review provides an in-depth overview of current CRISPR development, including the advantages and disadvantages of the technology, recent applications, and future considerations.
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Humans , CRISPR-Cas Systems , Clustered Regularly Interspaced Short Palindromic Repeats , Crops, Agricultural/genetics , Gene Editing/methods , Genetic Therapy , Nobel Prize , Plant BreedingABSTRACT
Objective To verify whether β-arrestin-2 inhibits autophagy by up-regulating PI3K/Akt signal to protect the liver from ischemia-reperfusion injury (IRI) in mice. Methods Twelve β-arrestin-2 knockout (KO) and twelve wild-type (WT) C57BL/6 mice were randomly divided into the KO+sham group, KO+IRI group, WT+sham group and WT+IRI group, six mice in each group. The mouse models with 70% liver IRI were established or sham operation was performed. Relevant experiments were carried out at 6 h after liver reperfusion or operation. The expression levels of apoptosis signal protein cleaved Caspase-3, proliferation signal protein Ki-67 and the PI3K/Akt signal protein p-Akt were detected by immunohistochemical staining. Results Immunohistochemical staining demonstrated that compared with the corresponding sham group, the positive cell count for cleaved Caspase-3, Ki-67 and p-Akt in liver tissues of mice was significantly increased in the KO+IRI and WT+IRI groups (all P < 0.01). Compared with the WT+IRI group, the positive cell count for cleaved Caspase-3 in liver tissues of mice was significantly increased, whereas the positive cell count forKi-67 and p-Akt was significantly decreased in the KO+IRI group (both P < 0.05). Conclusions β-arrestin-2 can mitigate the liver cell apoptosis and promote the repair of injury after IRI in mice. Moreover, β-arrestin-2 inhibits autophagy by up-regulating the PI3K/Akt signal to alleviate liver IRI in mice.
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Objective To analyze tumor immune microenvironment and related mechanisms in liver cancer.Methods We included 10 cases of hepatocellular carcinoma,hepatitis B patients and healthy volunteers from January 2015 to December 2017 in Shanxi Grand Hospital.We first detected the peripheral and local GM-CSF level in each group,detected myeloid-derived suppressor cells (MDSCs) GM-CSF and pathway-related protein expression.from liver cancer,tumor margin and normal liver tissue through flow cytometry and immunohistochemistry,Finally,we transfected the CCR4-NOT transcriptional complex subunit 7 (CNOT7) recombinant plasmid in the hepatoma cell line,and then detected the related protein expression.Results There was no significant difference for peripheral blood GM-CSF level between liver cancer group,hepatitis group and control group (P＞0.05).The level of local GM-CSF was (32.2±8.9) ng/L,which was higher than that of hepatocellular carcinoma (9.7±2.7) ng/L and normal liver tissue (11.6±2.9) ng/L.The difference was statistically significant (P＜0.05).The proportion of MDSCs at the edge of the tumor was (9.9 ±3.6) ％,which was higher than that of liver cancer (4.0± 1.5) ％ and normal liver tissue (6.3±2.3) ％,and the difference was statistically significant (P＜0.05).Immunohistochemistrydata was consistent with previous data.Compared with normal liver tissue,CNOT7 and STAT3 were highly expressed in liver cancer tissues,while STAT1 was lowly expressed.HepG2 human hepatoma cells were selected for transfection.Compared with the empty plasmid group,CNOT7 expression was decreased in the knocking out group at the same time STAT1 expression was increased,STAT3 and GM-CSF expression was decreased.Conclusion In hepatocellular carcinoma,the secretion of GM-CSF increased and the number of MDSCs increased.Knocking out CNOT7 reduced GM-CSF secretion and activate the JAK/STAT signaling pathway.
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Objective · To evaluate the influence of cathepsin S(CatS) on the severity of communicating hydrocephalus in a kaolin injected mouse model.Methods · Kaolin suspension was injected to 8 CatS knock-out (CatS -/-) mice and 12 wild type (WT) C57BL/6 mice through cisterna magna to establish communicating hydrocephalus mouse model. Cerebral magnetic resonance imaging (MRI) was used before and 1 week after kaolin injection to compare lateral ventricular volume. Lateral ventricular index was calculated to analyze the severity of hydrocephalus. Results · One week after kaolin injection,1 in CatS -/- group and 2 in WT group died. The mortality rate was 12.5% each and there was no significant difference (P=1.000). MRI results showed varying degrees of ventriculomegaly in both groups. Lateral ventricular index of CatS -/-group (n=8) and WT group (n=16) before kaolin injection was 0.05±0.01 and 0.04±0.01 respectively (P=0.720). One week after kaolin injection, lateral ventricular index of CatS-/- group (n=7) and WT group (n=14)was 0.13±0.02 and 0.11±0.01 respectively (P=0.950). In each group, in 71.4% of mice, lateral ventricular index enlarged twice or more. Conclusion · One week after kaolin injection into cisterna magna, lateral ventricles enlarges obviously, indicating hydrocephalus occurs, with high success rate. CatS gene deficiency has no significant influence on the development of communicating hydrocephalus.
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Objective · To evaluate the influence of cathepsin S(CatS) on the severity of communicating hydrocephalus in a kaolin injected mouse model.Methods · Kaolin suspension was injected to 8 CatS knock-out (CatS -/-) mice and 12 wild type (WT) C57BL/6 mice through cisterna magna to establish communicating hydrocephalus mouse model. Cerebral magnetic resonance imaging (MRI) was used before and 1 week after kaolin injection to compare lateral ventricular volume. Lateral ventricular index was calculated to analyze the severity of hydrocephalus. Results · One week after kaolin injection,1 in CatS -/- group and 2 in WT group died. The mortality rate was 12.5% each and there was no significant difference (P=1.000). MRI results showed varying degrees of ventriculomegaly in both groups. Lateral ventricular index of CatS -/-group (n=8) and WT group (n=16) before kaolin injection was 0.05±0.01 and 0.04±0.01 respectively (P=0.720). One week after kaolin injection, lateral ventricular index of CatS-/- group (n=7) and WT group (n=14)was 0.13±0.02 and 0.11±0.01 respectively (P=0.950). In each group, in 71.4% of mice, lateral ventricular index enlarged twice or more. Conclusion · One week after kaolin injection into cisterna magna, lateral ventricles enlarges obviously, indicating hydrocephalus occurs, with high success rate. CatS gene deficiency has no significant influence on the development of communicating hydrocephalus.
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Objective To explore the role of 18 ku translocator protein (TSPO) in the anti-post-traumatic-stress-disorder(PTSD) effects of YL-IPA08 and the value of TSPO as a potential pharmacological target using gene knock out mice.Methods The PCR method was used to genotype TSPO wild type (WT) mice and knock out (KO) mice.Foot shock was used to establish a well-accepted mouse model of PTSD,the open field test (OFT) was used to evaluate the locomotor activity in mice,and freezing measurement was used to evaluate the PTSD-like fear behavior in mice.Results Compared with TSPO WT mice,KO mice had no expressible TSPO gene,but showed similar locomotor activity to WT mice after PTSD modeling.On day 1,day 5 and day 16 after PTSD modeling (day-1-day 0),both WT and KO mice showed significant PTSD-like behavior with enhanced freezing time.However,8 d treatment (day 0-day 7) of YL-IPA08 (0.3 mg/kg,once daily) or positive drug sertraline (15 mg/kg,once daily) after PTSD modeling significantly reduced freezing time selectively in WT mice,but not in KO mice.Conclusion It has been found for the first time that TSPO WT and KO mice can show the same sensitivity to PTSD modeling (namely the same PTSD-like behavior performance).Interestingly,TSPO can mediate the anti-PTSD effects of YL-IPA08.Therefore,the present study provides direct evidence for the value of TSPO as an potential pharmacological target for PTSD.
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Objective To investigate the role of Glial cells missing 2 (Gcm2) in pathogenesis of hypoparathyroidism by knocking out Gcm2 gene in adult mice.Methods Tamoxifen was used to induce conditional knock-out of Gcm2 gene in Gcm2E2fl/flCre-ER mice.Genotypes of knock-out mice were identified by PCR.The protein expression level of Gcm2 was measured by Western blotting.The serum calcium and phosphorus were detected by the calcium and phosphorus assay kits, and the serum parathyroid hormone (PTH) level was detected by ELISA.Parathyroid cell proliferation was tested by Ki-67 immunohistochemical assay.The mRNA expression levels of PTH and calcium sensing receptor (CaSR) were detected by Real-time PCR.Bone mineral density was detected by micro CT.Results Gcm2 gene of parathyroid was confirmed to be knocked out by PCR.Compared with wild type and solvent control groups, Gcm2 knock-out group showed markedly lower protein expression of Gcm2, notably higher serum phosphorus and lower serum calcium and PTH concentrations (all P<0.01).The proliferation of parathyroid cells in Gcm2 knock-out mice were significantly higher(both P<0.01).The mRNA levels of PTH and CaSR in parathyroid gland of the knock-out group were significantly reduced (all P<0.01).Bone mineral density was significantly higher in Gcm2 knock-out group (all P<0.01).Conclusion Knockout of Gcm2 can lead to hypoparathyroidism in adult mice, indicating that Gcm2 is probably a therapeutic target for hypoparathyroidism.
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Objective To investigate the role of non-small cell lung cancer metastasis-related Trim72 gene in hepatocellular carcinoma (HCC) using clustered regularly interspaced short palindromic repeats (CRISPR) Cas9 system.Methods Hepa1-6 (Cas9) HCC cells were established with stable expression of Cas9 protein,and then specific gene knockout was performed using sgRNA targeting Trim72 gene.After obtaining the Hepa1-6 (Trim72-KO) cells,the metastasis and invasion abilities of the cells were evaluated by in vitro Transwell assay and in vivo subcutaneous lung metastasis examination.Results Hepa1-6 (Trim72-KO) cell line was successfully established by the CRISPR-Cas9 system.Transwell assay indicated that the mobility of Hepa1-6 (Trim72-KO) cells was increased compared to the control cells.Transwell assay indicated that the metastasis and invasion of Hepa1-6 (Cas9) HCC cells were enhanced after the knockout of Trim72 gene.The pathological examination of lung metastasis of subcutaneous tumor in vivo showed that the subcutaneously metastatic ability of Hepa1-6 (Trim72-KO) cells (the experimental group) was significantly stronger than Hepa1-6 (Cas9) cells (the control troup) that were not transferred to the corresponding sgRNA.Conclusions The trim72 gene knocked-out HCC cells were obtained by CRISPR-Cas9 system,which showed stronger metastasis and invasion abilities than the control cells.It is suggested that Trim72 gene may play an important role in the invasion and metastasis of HCC,and Trim 72 gene is expected to be a potential target for gene therapy of liver cancer.
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Objective CRISPR/Cas9 genome-editing technique provides an novel method for whole genome editing in eukaryotic cells.Recently,we found that gene subtype library with smaller size and focused pur-pose is more economical and practical. In this study,we aimed to target kinases,a group of pivotal cell signal transducers,to construct a kinase knock-out library using CRISPR/Cas9 technique.The construction strategy wll al-so be discussed. Methods 10 sgRNA was designed for each kinase target.After oligo pool synthesis by semicon-ductor chip,the oligos were eluted from the chip. The oligo templates were amplified and cloned into Cas9 vector and transformed into Stble3 competent cells.Monoclonal colonies were selected for DNA sequencing. Results(1) GO analysis of 507 cell kinases showed that the cell kinases took part in a wide range of cell signaling.(2)The sgRNA pool with about 140 bp in length was successfully amplified by using oligo pool as the template and univer-sal PCR primers.(3)In 40 identified library clones,34 clones were sequenced successfully. Among them,the DNA sequencing results of 25 samples were completely consistent with the designed target sequences.But there are some mutations in the primers of 9 samples.Failure in bacteria shaking,DNA sequencing and other factors were ex-isted in the other clones. Conclusion The CRISPR/Cas9 kinase knock-out library can be widely used for screen-ing the important kinases which may mediate cell proliferation,metastasis,drug resistance and autophagy.This li-brary will play an important role in clarifying the development of disease associated with kinases.
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Periaxin, a protein of noncompact myelin, is specifically expressed in the peripheral nervous system (PNS). There are two protein isoform L-periaxin and S-Periaxin by alternative splicing of periaxin gene, playing an important role in the initiation of myelin formation. So far, 18 different mutation sites in L-periaxin gene have been found to induce the peripheral demyelinating neurological charcot-marie-tooth diseases subtype 4F (CMT4F). The technique of activation of transcription activator-like effector nucleases (TALENS) was used to knock out the L-periaxin gene in RSC 96 cell line of Rattus. According to the design principle, the knock-out site of L-periaxin was assured to NLS domain of L-periaxin, which is target sequence of left and right arms of TALEN. The knock-out vectors of TALEN-L and TALEN-R were established and transfected into RSC96 cell. After puromycin screening, L-periaxin was knocked out successfully in RSC96 cell, which is confirmed by DNA sequence. The mutation efficiency is 21.6%. S-periaxin, not L-periaxin can be detected by Western blotting in L-periaxin gene knock-out RSC96 cell. The cell growth rate was decreased and the number of cells in G1 increased and decreased in S phase in L-periaxin gene knock-out RSC96 cell by flow cytometry and MTT assay.
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Animals , Rats , Cell Line , Charcot-Marie-Tooth Disease , Genetics , Gene Knockout Techniques , Membrane Proteins , Genetics , Mutation , Protein IsoformsABSTRACT
In order to construct an Escherichia coli strain with high sensitivity and specificity to detect arsenic ion using fluorescence as reporter, a sensitive strain to arsenic ion was obtained by knocking out the gene arsB that acts as an arsenic efflux pump. The pET28b vector containing arsenite detecting cassette Pars-arsR-egfp was constructed and then transformed into arsB deleted mutant. Measuring conditions of this constructed whole-cell biosensor were optimized and its linear concentration range, limit of detection and specificity were determined. This modified biosensor was much more sensitive than that using wild-type strain as host. The optimal detection range of As³⁺ concentration was 0.013 to 42.71 μmol/L, and the limit concentration of detection was as low as 5.13 nmol/L. Thus we successfully improved the sensitivity of arsenite detecting biosensor by modification of E. coli genome, which may provide useful strategies for development and optimization of microbial sensors to detect heavy metals.
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Arsenites , Biosensing Techniques , Escherichia coli , Genetics , Gene Knockout Techniques , Metals, Heavy , Microorganisms, Genetically-Modified , Water , ChemistryABSTRACT
This study investigated the effects of SIRT1 gene knock-out on osteoarthritis in mice, and the possible roles of SREBP2 protein and the PI3K/AKT signaling pathway in the effects. Mice were randomly divided into a normal group and a SIRT1 gene knock-out group (6 mice in each group). In these groups, one side of the knee anterior cruciate ligament was traversed, and the ipsilateral medial meniscus was cut to establish an osteoarthritis model of knee joint. The countralateral synovial bursa was cut out, serving as controls. The knee joint specimens were then divided into four groups: SIRT1control group (group A, n=6); SIRT1osteoarthritis group (group B, n=6); SIRT1control group (group C, n=6); SIRT1osteoarthritis group (group D, n=6). HE staining, Masson staining, Safranin O-Fast Green staining and Van Gieson staining were used to observe the morphological changes in the articular cartilage of the knee. Immunohistochemical staining was employed to detect the expression of SIRT1, SREBP2, VEGF, AKT, HMGCR and type II collagen proteins. SA-β-gal staining was utilized to evaluate chondrocyte aging. The results showed clear knee joint cartilage destruction and degeneration in the SIRT1osteoarthritis group. The tidal line was twisted and displaced anteriorly. Type II collagen was destroyed and distributed unevenly. Compared with the SIRT1osteoarthritis group and SIRT1control group, SIRT1 protein expression was not obviously changed in the SIRT1osteoarthritis group (P>0.05), while the expression levels of the SREBP2, VEGF and HMGCR proteins were significantly increased (P<0.05) and the levels of AKT and type II collagen proteins were significantly decreased (P<0.05). SIRT1 gene knock-out may aggravate cartilage degeneration in osteoarthritis by activating the SREBP2 protein-mediated PI3K/AKT signalling pathway, suggesting that SIRT1 gene may play a protective role against osteoarthritis.
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Animals , Humans , Mice , Cartilage , Pathology , Chondrocytes , Metabolism , Collagen Type II , Metabolism , Disease Models, Animal , Knee Joint , Metabolism , Pathology , Mice, Knockout , Oncogene Protein v-akt , Genetics , Osteoarthritis , Genetics , Pathology , Phosphatidylinositol 3-Kinases , Genetics , Signal Transduction , Genetics , Sirtuin 1 , Genetics , Sterol Regulatory Element Binding Protein 2 , Genetics , Vascular Endothelial Growth Factor AABSTRACT
Objective To preliminarily explore the effects of gene knock-out and overexpression of aldolase A on tumor cell proliferation, and then confirm the relationship between aldolase A and tumor growth during the process of anaerobic metabolism. Methods Through vector plasmid building and lentiviral infection, the cell lines stably overexpressing aldolase A and its gene knock- out cell lines were constructed respectively. The restructured cell lines were validated on gene and protein levels. Then, the changes of cell proliferation ratio were observed. Results Real time PCR results showed that aldolase A gene expression of the overexpressing cell line was about 3 times that of the normal cells. Among the five interfering targets of aldolase A designed according to aldolase A RNA sequences, aldolase A4 had more obvious interference effect on the target gene expression, the aldolase A mRNA level of which was about 1/50 of the normal cells. Compared with normal control group, the proliferation rate of aldolase A gene overexpression significantly increased by 40% in 48 h(P<0.05), while the proliferation rate of aldolase A gene knock out cells significantly de? creased about 86% in 24 h(P<0.05). Conclusion Aldolase A expressions have obvious effects on hepatocellular carcinoma cells.
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Objective To preliminarily explore the effects of gene knock-out and overexpression of aldolase A on tumor cell proliferation,and then confirm the relationship between aldolase A and tumor growth during the process of anaerobic metabolism. Methods Through vector plasmid building and lentiviral infection,the cell lines stably overexpressing aldolase A and its gene knock-out cell lines were constructed respectively. The restructured cell lines were validated on gene and protein levels. Then ,the changes of cell proliferation ratio were observed. Results Real time PCR results showed that aldolase A gene expression of the overex?pressing cell line was about 3 times that of the normal cells. Among the five interfering targets of aldolase A designed according to aldol?ase A RNA sequences,aldolase A4 had more obvious interference effect on the target gene expression,the aldolase A mRNA level of which was about 1/50 of the normal cells. Compared with normal control group,the proliferation rate of aldolase A gene overexpression significantly increased by 40% in 48 h(P<0.05),while the proliferation rate of aldolase A gene knock out cells significantly de?creased about 86%in 24 h(P<0.05). Conclusion Aldolase A expressions have obvious effects on hepatocellular carcinoma cells.
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Objective To construct mutant strains of Klebsiella pneumoniae with ampG gene dele-tion by homologous recombination and to evaluate the role of ampG gene in inducing the expression of AmpC enzyme.Methods Polymerase chain reaction ( PCR) was used to amplify the upstream and downstream fragments of ampG gene.The gene splicing by overlap extension PCR ( SOE-PCR) technique was used to construct the fusion fragment , which was then ligated into the temperature sensitive suicide vector pKO 3-km after enzyme digestion as pKO3-km-ΔampG.To achieve allelic exchange , the plasmid pKO3-km-ΔampG was introduced into Kp1 and Kp NTUH-K2044 strains by electroporation .The mutant strains of Klebsiella pneu-moniae with ampG gene deletion were screened out .The plasmid pACYC184-ampCR was introduced into the Kp NTUH-K2044 wild-type strain and its mutant strain with ampG gene deletion to make them harbor the gene encoding AmpC enzyme .The disk diffusion method was used to evaluate the effects of ampG gene on the expression of AmpC enzyme in Klebsiella pneumoniae strains with cefoxitin as the inducer .Results The recombinant plasmid pKO3-km-ΔampG was constructed successfully .The mutant strains of Klebsiella pneu-moniae with ampG gene deletion were constructed as verified by PCR and DNA sequencing .Compared with the Kp1 wild type strain, no AmpC enzyme was produced by the ampG gene knock-out Kp1 strain.The Kp NTUH-K2044 strain could produce AmpC enzyme , while the mutant strain of Kp NTUH-K2044 with ampG gene deletion could not after introduced the pACYC 184-ampCR plasmid .Conclusion The mutant strain of Klebsiella pneumoniae with ampG gene deletion was successfully constructed .The Klebsiella pneumonia strain without the ampG gene could not produce the AmpC enzyme .
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Objective To knock out the Abcb1 gene of rat,and establish the Abcb1 humanized rat model based on the Abcb1 knock out rat.Methods The animal model was established using BAC and CRISPR/Cas9 technology,and was analyzed by PCR, RT-PCR and real-time PCR.Results Establishing a rat model expressing human Abcb1 stably by transfer the 153 kb BAC containing human Abcb1 promoter and cDNA into rat genome, and establishing the Abcb1 knock out rat at the same time.Establishing the Abcb1 humanized model by crossing these two strains together.The expression pattern of Abcb1 in Abcb1 humanized rat is different from the wild type rat.The Abcb1 humanized model express not only the human Abcb1 gene but also has similar expression pattern as human.Conclusions The Abcb1 knock out rat and the Abcb1 humanized rat were successfully established, and this model is close to human concerning about the drug metabolism related to Abcb1.
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Objective In order to get genetic markers,an auxotrophic paclitaxel-producing fungus named Pestalotiopsis malicola N8 strain was isolated by genetic modification.Methods Based on the homologous recombination,URA-3 which is the key gene for uracil synthetic route of Pestalotiopsis malicola N8 strain was knocked out.The transformants were screened by minimal medium with the combination of 5-fluoroorotic acid (5-FOA) and uracil.Results The results showed that the uracil auxotrophic strain was able to grow in the minimal medium containing 5-FOA and uracil while the wild type strain was not.Conclusions The uracil auxotrophic strain can be used as a new selection marker for future gene function studies of N8 strain.
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Objective To observe the effect of Ruanmailing Oral Liquid on angiogenesis in atherosclerosis plaque of Apolipoprotein E (ApoE) gene knock-out mice, and explore the mechanisms of plaque stabilizing. Methods Totally 30 mice 6-8 weeks old ApoE knockout mice were fed a high fat diet for 12 weeks until the formation of a mature atherosclerotic plaque. They were randomly divided into three groups-model group, Ruanmailing group, simvastatin group, with another 6 normal C57BL/6J mice as the control group, and were administered for 12 weeks. Blood was extracted from orbital venous to measure the lipid (TC, TG, LDL-C, HDL-C) variation. HE-stain was used to observe aortic pathomorphological changes, meanwhile, immunohistochemical method was adopted to determine the microvessel density of plagues which is marked by CD105, as well as the expression of CD105 in aorta. Results Compared with the model group, TC, LDL-C, TG of Ruanmailing group and simvastatin group decreased significantly, while HDL-C increased significantly (P0.05). Conclusion Ruanmailing Oral Liquid may reduce the expression of CD105 and inhibit the angiogenesis within the plaque, which is the possible mechanism of stabilizing the atherosclerotic plaque.
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ObjectiveTo investigate the effects of Akt3 gene knockout on neuropathic pain behaviors induced by chronic constriction injury of sciatic nerve (CCI).MethodsExperiment was divided into two groups:Akt3 knockout group (Akt3-/-,n =12),wild type group (WT,n =12 ).Randomly numbered,the right sciatic nerve of mice were received the operation of chronic constriction injury.Paw withdrawal mechanical threshold (PWMT)and paw withdrawal thermal latency (PWTL) were tested on day 1 before operation and day 1,3,5,7,10,14,17,21 afterCCI.ResultsThe basic values of PWMT(right:(1.09±0.20)g,(1.17±0.22)g;left:(1.17±0.15)g,(1.22±0.23)g,P＞0.05) andPWTL(right:(6.18±1.11)s,(6.20±1.25)s;left:(5.82±0.91)s,(5.92± 1.71 ) s,P ＞ 0.05 ) had no statistically significant differences between two groups.On day 1 after operation,compared with basic values,the PWMT and PWTL of the right paw in both Akt3-/- group and WT group decreased significantly (P ＜ 0.05 ),and at least lasted up to day 21.The PWMT( 3d:(0.42 ± 0.22 ) g,(0.72 ± 0.36) g ; 17d:(0.29 ±0.15)g,(0.49 ±0.19) g;21d:(0.27 ±0.18)g,(0.56 ±0.15)g,P＜0.05) and PWTL(5d:(2.43 ±0.68)s,(3.13±0.52)s;17d:(2.43±1.26)s,(3.84±1.29)s ;21d:(2.14±1.23)s,(4.07±1.26)s,P＜0.05 ) of the right paw in Akt3-/- group was significantly lower than those in WT group.The PWMT and PWTL of the left paw in Akt3-/- group and WT group had no obvious differences (P ＞ 0.05 ). However.compared to left paw,the PWMT and PWTL of the right paw of the two groups were obviously lower (P ＜ 0.05 ).ConclusionThe neuropathic pain induced by CCI increased in Akt3 gene knockout mice.
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Objective To determine the effect of cheA gene of Helicobacter pylori in the bacterial chemotaxis in vitro and colonization in vivo. Methods The entire cheA and cheY genes were amplified and cloned from genomic DNA of H. pylori NCTC11637 strain. Subsequently, the prokaryotic expression systems of cheA and cheY genes were generated and the target recombinant proteins rCheA and rCheY were extracted by Ni-NTA affinity chromatography. Rabbits were immunized with either rCheA or rCheY for obtaining antisera, and rCheA-IgG and rCheY-IgG in the antisera were prepared using ammonium sulfate precipitation plus DEAE-52 column chromatography. A suicide plasmid of cheA gene was constructed and then a cheA gene knock-out mutant ( cheA - ) was generated based on homologous recombinant exchange using the suicide plasmid. The cheA- mutant was identified using PCR and sequencing. The phosphorylation levels of CheA and CheY molecules of cheA - and wild-type strain were determined by using rCheA-IgG and rCheY-IgG anchoring the target proteins and protein phosphorylation detection kit. The differences of chemotaxis in vitro and colonization in vivo between cheA- mutant and wild-type strain were compared using chemotactic model and BALB/c infection model of H. pylori. Results The cheA gene knock-out in genome of cheA- mutant was confirmed by the results of PCR and sequencing. After treated with 0. 001-0. 1 mol/L HCI for 10 min, the phosphorylation levels of CheA and CheY molecules of wild-type strain were rapidly descended from ( 59.6 ±11.5) μmol and (55.5 ± 10.2) μmol to ( 10.8 ± 2.6) and (5. 5 ± 1.2) μmol (P ＜ 0.05 ), while the phosphorylation of CheY molecule of cheA - mutant was no markedly changed with a persistent lower level ( P ＞0.05). The diameters [(10-20) ± (2-3) mm] of chemotactic aggregative rings of cheA- mutant were significantly less than those [(16-24) ± (2-3)mm] of wild-type strain (P ＜0.05). The positive isolation rate (90%) of H. pylori in gastric biopsy specimens of mice that infected with wild-type strain was remarkably higher than that (40%) of mice that infected with cheA- mutant (P ＜0.05). The result of fluorescence quantitative was also showed that the numbers (6.3 × 103 ±2.1 × 103 copies/mg) of H. pylori in gastric biopsy specimens of wild-type strain infected mice were significantly larger than those (8.3 × 101 ±3. 1 × 101 copies/mg) in gastric biopsy specimens ofcheA- mutant infected mice (P＜0.05). Conclusion The cheA gene of H. pylori has an important role in the bacterial chemotaxis in vitro and colonization in vivo.