Expression of Gn protein of severe fever with thrombocytopenia syndrome virus and its immunogenicity / 中国生物制品学杂志

@#Objective To express the Gn protein of severe fever with thrombocytopenia syndrome virus(SFTSV) through adeno-associated virus 9(AAV9) expression system and evaluate its immunogenicity.Methods SFTSV Gn gene was inserted into viral vector pAAV-CMV-FH and the recombinant plasmid was transfected into HEK293T cells to obtain recombinant virus AAV9-Gn.The expression of Gn protein was determined by immunofluorescence and Western blot.Eighteen fernale BALB/c mice were randomly divided into three groups:Mock group(serum-free DMEM),AAV9-GFP group(1 × 10~(11) vg) and AAV9-Gn group(1 × 10~(11) vg),all of which were injected intramuscularly into the right hind limb at a dose of 100 μL per mouse.The body mass,diet,behavior and mental state of mice in each group were monitored continuously for 21 d,and the change rate of body mass was calculated;At 2,4,8 and 16 weeks after immunization,the levels of SFTSV neutralizing antibody in serum of mice in each group were detected by fluorescent reduction neutralization test(FRNT),and the levels of specific IgGl and IgG2a in serum of mice in AAV9-Gn group were detected by ELISA.Results After incubation with specific antibody,Vero cells transfected with AAV9-Gn showed specific green fluorescence under fluorescence microscope,and had specific binding to mouse anti-SFTSV Gn monoclonal antibody,and the specific binding bands were found at a relative molecular mass of about 61 000.The body mass of the three groups showed an increasing trend,there was no significant difference between the three groups(F=0.158—2.621,P> 0.05),and the diet,behavior and mental state were normal.At 2,4,8 and 16 weeks after immunization,the titer of SFTSV neutralizing antibody in serum of mice in AAV9-Gn group was significantly higher than that of Mock group and AAV9-GFP group(H=13.332—14.538,each P <0.001),and the titer peak appeared at 8 weeks;The level of specific IgG1 in serum of mice was significantly higher than that of IgG2a(F=4.373—12.975,each P <0.05) at different time points.Conclusion SFTSV Gn protein can be expressed correctly through AAV9 expression system,and has low toxicity to mice with good immunogenicity,which is expected to be a candidate component of SFTSV vaccine.

Development and verification of anion-exchange high-performance liquid chromatography for determination of empty capsid ratio in recombinant adeno-associated virus type 9 / 中国生物制品学杂志

@#Objective To develop and verify an anion-exchange high-performance liquid chromatography(AEX-HPLC)method for the determination of empty capsid ratio of recombinant adeno-associated virus type 9(rAAV9).Methods AEXHPLC based on the differences in surface charge was used to establish a method for detecting the ratio of empty and full capsid rAAV9 by optimizing the elution gradient of mobile phase,pH,column temperature,flow rate,sample concentration,injection volume and detection wavelength of fluorescence detector. The specificity,linearity,limit of detection(LOD),limit of quantitation(LOQ),precision and accuracy of the method were verified to confirm the feasibility.Results Using a CIMac AAV full/empty-0. 1 mL column,20 mmol/L BIS-Tris propane(BTP)as mobile phase A and 20 mmol/L BTP+1 mol/L NaCl as mobile phase B,gradient elution was performed with pH of 9.0,column temperature of 20 ℃,flow rate of1 mL/min,sample concentration of 4×10~(12)vg/mL,injection volume of 10 μL,excitation wavelength of 280 nm and emission wavelength of 330 nm,which realised the baseline isolation and quantitative detection of empty and full capsid rAAV9. The verification results of the method showed that the preparation buffer had no interference with good specificity;rAAV9 showed a good linear relationship in the range of(1.6-8)×10~(12)vg/mL,r = 0. 993;the LOD was 5×10~(10)vg/mL,and the LOQ was 1×10~(11)vg/mL;the RSD of repeatability and intermediate precision were 2. 95% and 2. 10%,respectively;the accuracy rates were not less than 80%.Conclusion A highly sensitive and rapid AEX-HPLC method for determination of the ratio of empty capsid to full capsid rAAV9 was developed,which could be used for the analysis of empty capsid rate and quality control in gene therapy products.

Comparison of two pretreatment methods for detection of free and mispackaged host cell DNA in recombinant adeno-associated virus / 中国生物制品学杂志

@#Objective To compare the application of two pretreatment methods,deoxyribonuclease(DNase)treatment and ligand affinity,in detecting the residual amount of free and mispackaged host cell DNA(HCDNA)in recombinant adenoassociated virus(rAAV).Methods Free and mispackaged HCDNA were isolated by DNase treatment and ligand affinity respectively,and then the nucleic acid was extracted and detected by qPCR. The accuracy and reproducibility of two pretreatment methods for detecting HCDNA residues were compared.Results Using DNase treatment,the result of nucleic acid quantitative detection in non-DNase-treated group was the total residual amount of HCDNA,that in DNase-treated group was the amount of mispackaged HCDNA,and the difference between them was the residual amount of free HCDNA. The recovery rates of both the untreated and treated groups were more than 75%,and the RSD of reproducibility was less than 30%. Using affinity extraction method,with the affinity ligand combined with rAAV,the result of recovery rate of mispackaged HCDNA was over 75%,and that of free HCDNA was only 36%.Conclusion DNase treatment method can effectively detect free and mispackaged HCDNA,laying a foundation for further research.

Analysis on integrity of target nucleic acid in recombinant adeno-associated virus / 中国生物制品学杂志

@#Objective To explore a method for detecting the integrity of target nucleic acid in recombinant adeno-associated virus(rAAV),and establish a preliminary analysis algorithm.Methods The free DNA fragment of rAAV was digested,and the virus genome was extracted.Five pairs of overlapping primers were designed,using the orthogonal array method,which were detected by digital PCR respectively,with conventional conditions:20 μL reaction system with EveGreen and4 μL template,and digital PCR conditions:95 ℃ 5 min;95 ℃ 15 s,55 ℃ 30 s,72 ℃ 90 s for 45 cycles.The enhancement condition of ultra-long nucleic acid fragment was 25 μL reaction system with Mix B-2 000 bp and 2 μL template,and the quantitative analysis was performed by using the software attached to the instrument.Using the least square method,the number of full-length fragments was fitted and analyzed,and then the integrity distribution of target nucleic acid was interpreted.Results The fragments with the distance between primers of no more than 1 200 nt were amplified effectively,and a series of effective copies of fragments with a length of about 1 000 nt were obtained by systematic analysis.The copy number of common fragments was fitted and analyzed by the least square method.It was estimated that the full-length fragments in the sample were no more than 1 234 copies/μL,and there was a signficant difference(P < 0.05)between this value and the maximum measured value of 1 443 copies/μL,with the difference of approximately 16.9%.Conclusion A preliminary detection method for the integrity of target nucleic acid in rAAV has been developed,and a certain amount of incomplete target nucleic acids were analyzed in the test sample,laying a foundation for further in-depth research.

Establishment and validation of a method for determination of interesting protein expression level in cells infected with recombinant adeno-associated virus / 中国生物制品学杂志

@#Objective To establish and validate a method for the determination of the interesting protein expression level of recombinant adeno-associated virus(rAAV)infected cells,so as to monitor the product quality in different stages of rAAV9production process.Methods After incubation of serial diluted rAAV samples with infection enhancer Envirus-AAV,the human malignant glioblastoma cells(U87-MG)pretreated with hydroxyurea(HU)were infected.Using rAAV9 reference as the standard,the expression level of glutaryl-CoA dehydrogenase(GCDH)was detected by ELISA,and the specificity,accuracy,precision,linear range,limit of quantitation(LOQ)and durability of the method were verified.Eight batches of rAAV9 samples were detected by the established method.Results The A_(450)-A_(630) value of the sample buffer was 0.3,which was slightly lower than the lowest dilution point(1 ng/mL)of the four-parameter standard curve for protein quantification.The average recoveries of samples with 150%,100% and 50% theoretical relative titer levels were in the range of 100.0%-107.3%.The RSDs of the target protein expression level of the samples with three theoretical relative titer levels detected by the same experimenter three times and different experimenters were all less than 25%.There was a good linear relationship between rAAV9 samples and the target protein expression levels in the range of 50%-150% theoretical relative titer levels,and the linear regression equation was y = 1.077 x-0.022,R~2= 0.984.The LOQ of the method was 0.59,namely 6.0×10~(12) vg/mL.After U87-MG cells were incubated with HU for different time(18,21,24 h),and the culture supernatant was stored under different conditions(room temperature for 0.5 h,below-60 ℃ for 12 h,below-60 ℃ for 24 h).The RSDs of target protein expression levels were all less than 25%.The target protein expression levels of 1-8 batches of rAAV9 samples were 111%,121%,72%,65%,86%,75%,102% and 91%,respectively.Conclusion The established method for the determination of the target protein expression level after rAAV infection has good specificity,accuracy,precision and durability,and can be used for the quality control of products in different stages of rAAV9 production.

Expression of Gn protein of severe fever with thrombocytopenia syndrome virus and its immunogenicity / 中国生物制品学杂志

@#Objective To express the Gn protein of severe fever with thrombocytopenia syndrome virus(SFTSV) through adeno-associated virus 9(AAV9) expression system and evaluate its immunogenicity.Methods SFTSV Gn gene was inserted into viral vector pAAV-CMV-FH and the recombinant plasmid was transfected into HEK293T cells to obtain recombinant virus AAV9-Gn.The expression of Gn protein was determined by immunofluorescence and Western blot.Eighteen fernale BALB/c mice were randomly divided into three groups:Mock group(serum-free DMEM),AAV9-GFP group(1 × 10~(11) vg) and AAV9-Gn group(1 × 10~(11) vg),all of which were injected intramuscularly into the right hind limb at a dose of 100 μL per mouse.The body mass,diet,behavior and mental state of mice in each group were monitored continuously for 21 d,and the change rate of body mass was calculated;At 2,4,8 and 16 weeks after immunization,the levels of SFTSV neutralizing antibody in serum of mice in each group were detected by fluorescent reduction neutralization test(FRNT),and the levels of specific IgGl and IgG2a in serum of mice in AAV9-Gn group were detected by ELISA.Results After incubation with specific antibody,Vero cells transfected with AAV9-Gn showed specific green fluorescence under fluorescence microscope,and had specific binding to mouse anti-SFTSV Gn monoclonal antibody,and the specific binding bands were found at a relative molecular mass of about 61 000.The body mass of the three groups showed an increasing trend,there was no significant difference between the three groups(F=0.158—2.621,P> 0.05),and the diet,behavior and mental state were normal.At 2,4,8 and 16 weeks after immunization,the titer of SFTSV neutralizing antibody in serum of mice in AAV9-Gn group was significantly higher than that of Mock group and AAV9-GFP group(H=13.332—14.538,each P <0.001),and the titer peak appeared at 8 weeks;The level of specific IgG1 in serum of mice was significantly higher than that of IgG2a(F=4.373—12.975,each P <0.05) at different time points.Conclusion SFTSV Gn protein can be expressed correctly through AAV9 expression system,and has low toxicity to mice with good immunogenicity,which is expected to be a candidate component of SFTSV vaccine.

Combination of AAV-delivered tumor suppressor PTEN with anti-PD-1 loaded depot gel for enhanced antitumor immunity

Recent clinical studies have shown that mutation of phosphatase and tensin homolog deleted on chromosome 10 (PTEN) gene in cancer cells may be associated with immunosuppressive tumor microenvironment (TME) and poor response to immune checkpoint blockade (ICB) therapy. Therefore, efficiently restoring PTEN gene expression in cancer cells is critical to improving the responding rate to ICB therapy. Here, we screened an adeno-associated virus (AAV) capsid for efficient PTEN gene delivery into B16F10 tumor cells. We demonstrated that intratumorally injected AAV6-PTEN successfully restored the tumor cell PTEN gene expression and effectively inhibited tumor progression by inducing tumor cell immunogenic cell death (ICD) and increasing immune cell infiltration. Moreover, we developed an anti-PD-1 loaded phospholipid-based phase separation gel (PPSG), which formed an in situ depot and sustainably release anti-PD-1 drugs within 42 days in vivo. In order to effectively inhibit the recurrence of melanoma, we further applied a triple therapy based on AAV6-PTEN, PPSG@anti-PD-1 and CpG, and showed that this triple therapy strategy enhanced the synergistic antitumor immune effect and also induced robust immune memory, which completely rejected tumor recurrence. We anticipate that this triple therapy could be used as a new tumor combination therapy with stronger immune activation capacity and tumor inhibition efficacy.

Influence of Transcription Factor KLF16 on Lipid Metabolism in Non-alcoholic Fatty Liver Disease / 中山大学学报(医学科学版)

ObjectiveTo explore the expression of transcription factor KLF16 in nonalcoholic fatty liver disease （NAFLD） and its effect on lipid metabolism. MethodsAn animal model of NAFLD was constructed in mice induced by a high-fat diet. The mice were divided into normal diet group （ND） and high fat diet group （HFD）. NAFLD cell model was constructed by primary mouse liver cells induced by oleic acid. The cells were divided into control group （Control group） and oleic acid induction group （OA group）. Real-time fluorescence quantitative PCR （RT-qPCR） and Western blot were used to detect KLF16 expression in NAFLD animal and cell models. In vitro and in vivo models of KLF16 knockdown were constructed by injection of adeno-associated virus （AAV） into mouse tail veins and transient transfection of cell siRNA. Hematoxylin-eosin staining （HE） and other methods were used to detect changes in lipid deposition in NAFLD models before and after KLF16 knockout. RT-qPCR was used to detect the expression of key genes of lipid metabolism in both cellular and animal NAFLD models before and after KLF16 knockdown. Western blot assay was used to detect the expression of endoplasmic reticulum stress protein in NAFLD model before and after KLF16 knockdown. ResultsThe expression level of KLF16 was up-regulated in HFD group and OA group， and lipid deposition was increased in OA group after KLF16 was depressed. There was no change in TC level in hepatocytes between groups （P>0.05）， and TG level was increased in different degrees （P<0.05， P<0.001）. At the same time， the change of KLF16 expression also caused the change of ER stress protein expression in OA group. ConclusionThe transcription factor KLF16 may alleviate lipid deposition in nonalcoholic fatty liver disease by endoplasmic reticulum stress.

Characterization analysis of capsid protein of recombinant adeno-associated virus 6 using reversed phase liquid chromatography-mass spectrometry / 中国生物制品学杂志

@#Objective To characterize the capsid proteins of recombinant adeno-associated virus 6(rAAV6)vectors by reversed phase liquid chromatography-mass spectrometry(RPLC-MS),including primary structure and post-translational modification(PTM).Methods The mobile phase A consisted of 0. 1% aqueous solution of difluoroacetic acid(DFA),while the mobile phase B was 0. 1% DFA acetonitrile solution. The column temperature was maintained at 80 ℃,and the gradient elution lasted for 10 min(0→10 min,mobile phase B 15%→45%). The ESI-Q-TOF mass spectrometry detection operated in positive ion mode with the scanning range of 400-4 000 m/z,the scanning frequency of 2 Hz,the cone voltage at 80 V,the capillary voltage at 3. 0 kV,and the ion source temperature at 120 ℃.Results The measured relative molecular mass of the AAV capsid proteins VP1,VP2,and VP3 was 81 255. 9,66 062. 9,and 59 488. 6,respectively. The deviations from the theoretical values were 8. 1 ppm for VP1,3. 8 ppm for VP2,and 36 ppm for VP3. Mass peptide profile analysis of the enzymatically digested rAAV6 sample indicated a sequence coverage of about 89% with detected PTMs mainly including deamidation,N-terminal acetylation,ubiquitination,and phosphorylation;no glycosylation modification sites were found. Tandem mass spectrometry confirmed the N-terminal and C-terminal sequences of the rAAV6 capsid protein as well as the N-terminal PTM.Conclusion The complete relative molecular mass of rAAV6 capsid protein was analyzed by RPLCMS technique,and the PTM of rAAV6 capsid protein was analyzed by tandem mass spectrometry at the peptide level,which has a certain significance for the quality control of AAV gene therapy products and the improvement of production process.

qPCR在重组腺相关病毒产品大片段宿主细胞残留DNA检测中的应用 / 中国生物制品学杂志

@#Objective To investigate the feasibility of using quantitative PCR(qPCR)technology to detect large fragments of host cell residual DNA(HCD)in recombinant adeno-associated virus(rAAV)gene therapy products.Methods Four different serotypes of rAAV were extracted for the nucleic acids,two fragment sequences of 244 bp and 562 bp within the long terminal repeat sequence(LTR)in the genome of host cells HEK293 were specifically quantified by qPCR,and the proportion of HCD in the total nucleic acids was calculated.Results Large fragments of HCD in qPCR quantifiable range were detected in four different serotype rAAV products,with the abundance ranging from 0. 3% to 5. 4%. As the length of the detected fragment increased,the abundance of HCD fragments showed a decreasing trend.Conclusion qPCR technology can be used to determine the presence of large fragments of HCD in rAAV products.

Prokaryotic expression of variable region protein of adeno-associated virus 9 capsid and preparation of polyclonal antibody / 中国生物制品学杂志

@#Objective To express and purify the protein of variable region of adeno-associated virus 9(AAV9) capsid in prokaryotic cells,and prepare rabbit polyclonal antibody against it.Methods DNA sequence encoding variable region of AAV9 capsid protein was designed,synthesized and inserted into prokaryotic expression vector pET-30a. The obtained plasmid pET-30a-AAV-VR was transformed to E.coli BL21(DE3),induced by IPTG to express the multivalent antigenic peptide and purified by Ni-NTA resin under denaturation conditions. Male Japanese large-eared white rabbits were immunized with the AAV9 variable region protein after dialysis and renaturation to prepare polyclonal antibody,which was determined for the antibody potency by indirect ELISA,and for the specificity by Western blot and cellular immunofluorescence.Results The recombinant prokaryotic expression plasmid pET-30a-AAV-VR expressing the variable region of AAV9 capsid was constructed correctly as identified by XhoⅠ and BglⅡ digestion. The expressed protein was recognized by His tag antibody after purification with a relative molecular mass of about 20 000. The potency of rabbit polyclonal antibody was 1∶10 240 000,which specifically recognize AAV9 capsid protein.Conclusion The capsid variable region protein of AAV9 was successfully expressed and rabbit polyclonal antibody with high potency was prepared,which laid a foundation of the subsequent development of AAV vector and the research of AAV biological function.

Protective effect of adeno-associated virus sense transfection ofGDFll on vascular injury in type 2 diabetic rats / 安徽医科大学学报

Objective@#To explore the effect of adenoassociated virus sense transfection up-regulating the expressionlevel of the growth and differential factor 11 ( GDF11) in vivo on aortic injury in type 2 diabetic mellitus rats(T2DM).@*Methods@#Nine-week-old male SD rats were randomly selected to establish a T2DM model by usinghigh -sugar and high-fat chow plus small-dose streptozotocin (STZ) combined induction. Both normal rats and diabetic model rats were randomly divided into five groups: blank control group ( Control group) , negative virus control group ( NC group), GDF11 adeno-associated virus group ( GDFl1 group), diabetic group ( DM group), anddiabetic + GDF11 adeno-associated virus group ( DM + GDFl1 group). After 8 weeks of feeding, the serum con-centrations of insulin ( INS ), advanced glyeosylation end products ( AGES), recombinant growth transforming fac.tor 11 ( GDF11 ), total cholesterol (T-CH0 ), triglycerides (TG), low-density lipoproteins (LDL-C), high-density lipoproteins ( HDL-C), asymmetric dimethylarginine ( ADMA), and malondialdehyde ( MDA) were assayed inthe rats ; periodic acid-schiff stain( PAS stain) was used to observe the sites of glycogen deposition, and hematoxylin-eosin staining ( HE) was used to observe vascular damage. Scanning electron microscopy was used to observethe damage of vascular endothelial cells and vascular elastic fibers, and protein blotting and immunohistochemistrwere used to detect the expression levels of vascular injury-related proteins. Protein blotting and immunohistochemistry were used to detect the expression levels of vascular injury-related proteins. @*Results@#The biochemical indexes showed that the serum concentrations of AGES, T-CHO, TG, LDL-C and MDA were higher in the DM groupthan those in the Control group (P <0. 05), the concentrations of INS, GDF11, HDL-C and ADMA were signifi.cantly lower than those in the Control group (P <0. 05 ), and the concentrations of AGE'S and HDL-C were not sig.nificantly lower in the DM + GDF1l group compared with the DM group ( P <0. 05). HDL-C was not significantlydilerent from the DM group, and several other data were improved ( P<0. 05 ). Pathological staining suggestedthat PAS staining in the DM group suggested that glycogen particles deposited in the endothelium and subendotheli.um of the aorta, HE staining observed thickening of the aortic mesentery, endothelial cells and elastic fibers brokeolf in an irregular alignment , and electron microscopy observed endothelial damage in the vasculature and elastic fibers broke off in the DM group, and these changes attenuated in the DM + GDFl1 group. Protein blotting and im.munohistochemistry indicated that the expression of endothelial cell-associated proteins decreased in the DM groug( P <0. 05), and mesenchymal markers elevated in the DM group ( P <0. 05 ), these proteins were regressed inthe DM + GDFl1 group, and the difference was statistically significant (P<0.05).@*Conclusion@#Inereasing theexpression level of GDFl1 in vivo can improve aortic vascular injury caused by diabetes mellitus, which is inferredthat it may be related to the inhibition of endothelial mesenchymal transition to protect the function of vascular endo.thelial cells and thus improve vascular injury.

Development of national standards for genomic titer determination of recombinant type 5 adeno-associated virus / 中国生物制品学杂志

@#ObjectiveTo develop a national standard for genomic titer determination of recombinant type 5 adeno-associated virus(rAAV5).MethodsThe rAAV5-GFP stock solution prepared by the three-plasmid system was identified and verified for the appearance,pH,sterility,genomic titer,purity and infection titer according to the relevant requirements of Chinese Pharmacopoeia(Volume Ⅲ,2020 edition),which was diluted and subpackaged to prepare candidate standards according to the results;The stability of candidate standards was investigated by thermal acceleration test;Three laboratories were organized to collaboratively calibrate the candidate standards using droplet digital PCR(ddPCR).ResultsAll the detection indexes of the candidate standard and the stock solution met the relevant requirements;The genomic titer showed no significant decrease at 25,4,-20,-40,-80 ℃ for 1,3,4,6 months;Through collaborative calibration by three laboratories,the candidate standard was assigned a value of 2. 56 × 10(12)copies/mL,and the 95% confidence interval was 2. 48 ×10(12)copies/mL,and the 95% confidence interval was 2. 48 ×10(12)copies/mL ～ 2. 64 × 10(12)copies/mL ～ 2. 64 × 10(12)copies/mL.ConclusionThe developed national standard for the determination of rAAV5 genomic titer had good stability and might be used for the quality evaluation of rAAV5 related products.

Application of biological mass spectrometry in quality control of adeno-associated virus carrier preparations / 中国药科大学学报

@#Adeno-associated virus (AAV) is a common viral vector used in gene therapy.Because of its high safety and its ability to target a variety of cells, it has been widely used in preclinical and clinical studies.However, during the design and production, AAV vectors have many key quality attributes that affect their safety and efficacy.The development and application of biological mass spectrometry technology provides a convenient platform for the research on biological macromolecules, especially in the aspects of protein sequence, structure and interaction.For AAV vectors, mass spectrometry can facilitate the determination or characterization of capsid protein ratio, post-translational modification, serotype, and empty capsid ratio, thus assisting in the quality control of AAV vectors.Compared with the existing methods, mass spectrometry has the advantages of smaller amount of sample size, faster and more sensitive analysis, being more suitable for the analysis of complete AAV vectors with higher mass resolution, and can distinguish empty capsids, full capsids and partial capsids.In the future, mass spectrometry technology is expected to play a more important role in the design and production of AAV vectors through the coupling of more efficient protein separation technology with mass spectrometry, the development of new information processing software platforms and new mass spectrometry detection techniques.

Optimization of transduction conditions of recombinant adeno-associated virus into NK92 cells / 中国药科大学学报

@#To improve the transduction efficiency of recombinant adeno-associated virus (rAAV) in NK92 cells, the number of cells, concentration of IL-2 in the medium, and serotype and dosage of rAAV were explored to optimize cell state and viral transfection conditions.Then, zinc chloride (ZnCl2), chloroquine, polyvinyl alcohol (PVA) and genistein with different concentration were added separately during transfection to further improve the viral transduction efficiency.The results showed that, at cell number of 5 × 105, the expression efficiency of enhanced green fluorescent protein (EGFP) was relatively high.When the IL-2 concentration was 1 000 IU/mL, NK92 cells were most suitable for virus transfection. The transduction efficiency of different serotypes of rAAV in NK92 cells was rAAV6, rAAV2 and rAAV9 in descending order.Pretreatment of NK92 cells with genistein could significantly increase the viral transduction efficiency, while the addition of other reagents had no significant effect.Through the optimization of the above conditions, the transduction efficiency of rAAV to NK92 cells could be significantly improved, which provided evidence for functional genetic modification of NK92 cells by rAAV.

Gene therapy in neuromuscular disorders / Terapia gênica nas doenças neuromusculares

Abstract Monogenic neuromuscular disorders are potentially treatable through gene therapy. Using viral vectors, a therapeutic transgene aims to restore normal levels of a protein not produced by the defective gene, or to silence a gene whose expression leads to toxic effects. Spinal Muscular Atrophy (SMA) is a good example of a monogenic disease that currently has an AAV9-based vector gene therapy as a therapeutic option. In this review, we intend to discuss the viral vectors and their mechanisms of action, in addition to reviewing the clinical trials that supported the approval of gene therapy (AVXS-101) for SMA as well as neuromuscular diseases that are potentially treatable with gene replacement therapy.

Resumo Doenças neuromusculares monogênicas são potencialmente tratáveis através de terapia gênica. Utilizando-se de vetores virais, um transgene terapêutico objetiva repor os níveis normais de uma proteina não produzida pelo gene defeituoso ou silenciar um gene cuja expressão leva a efeitos tóxicos. A Atrofia Muscular Espinhal (AME) é um bom exemplo de doença monogenica que atualmente tem uma terapia gênica com vetor viral AAV9 como opção terapêutica. Nesta revisão, pretendemos discutir os vetores virais e macanismos de ação utilizados, além de revisar os ensaios clínicos que embasaram a aprovação da terapia gênica (AVXS-101) para AME, assim como doenças neuromusculares potencialmente tratáveis com terapia de reposição gênica.

Pulmonary delivery of siRNA against acute lung injury/acute respiratory distress syndrome

The use of small interfering RNAs (siRNAs) has been under investigation for the treatment of several unmet medical needs, including acute lung injury/acute respiratory distress syndrome (ALI/ARDS) wherein siRNA may be implemented to modify the expression of pro-inflammatory cytokines and chemokines at the mRNA level. The properties such as clear anatomy, accessibility, and relatively low enzyme activity make the lung a good target for local siRNA therapy. However, the translation of siRNA is restricted by the inefficient delivery of siRNA therapeutics to the target cells due to the properties of naked siRNA. Thus, this review will focus on the various delivery systems that can be used and the different barriers that need to be surmounted for the development of stable inhalable siRNA formulations for human use before siRNA therapeutics for ALI/ARDS become available in the clinic.

Inhibitory effect of ILK-siRNA-AAV on scar formation after glaucoma filtering surgery in rats / 中华实验眼科杂志

Objective:To investigate the role of integrin-linked kinase (ILK)-small interfering RNA (siRNA)-adeno-associated virus (AAV) in scar formation after glaucoma filtering surgery in rat eyes.Methods:Forty-eight Sprague Dawley rats of SPF grade, aged 8 to 9 weeks old, were selected and divided into blank control group, ILK-siRNA-AAV group, NC-siRNA-AAV group and mitomycin C (MMC) group by random number table method, with 12 rats in each group.Left eyes of the rats were taken as experimental eyes, and no intervention was administered to fellow eyes.The bulbar conjunctival filtering bleb after glaucoma filtration surgery in rats was established by anterior chamber drainage tube implantation.One day after operation, phosphate buffer solution, ILK-siRNA-AAV, and NC-siRNA-AAV were injected into the filtering bleb of blank control group, ILK-siRNA-AAV group and NC-siRNA-AAV group, 5 μl each group, respectively.Cotton tablets containing 0.4 mg/ml MMC were placed under conjunctival flap for 5 minutes during operation in MMC group.Intraocular pressure (IOP) was measured with a handheld tonometer before surgery and at 1, 2, 3, 7, 14, 21, 28 days after surgery.Formation of filtering blebs in rats was observed with a surgical microscope at 1, 2, 3, 7, 14, 21, 28 days after operation, and the bleb survival time was calculated by Kaplan-Meier survival analysis.The mRNA and protein expression levels of ILK in conjunctival and subconjunctival tissues at the surgical sites were detected by reverse transcription PCR and Western blot, respectively, on the 28th day after operation.Silencing of ILK gene was identified.Effect of ILK gene silencing on the morphology of drainage pathway was observed by hematoxylin-eosin staining.Effect of ILK gene silencing on collagen fiber deposition in the bulbar conjunctiva at filtration area was examined by Masson staining, and the percentage of positive area of collagen fiber staining in the total tissue visual field was calculated.The use and care of the animals complied with the ARVO Statement.This research protocol was approved by an Ethics Committee of Xi'an Jiaotong University (No.2013-772). Results:There were statistically significant differences in IOP at different time points between before and after surgery among four groups ( Fgroup=76.84, P<0.001; Ftime=114.49, P<0.001). The IOP of ILK-siRNA-AAV group on the 1st, 7th, 14th and 28th day after operation and the IOP of MMC group on the 2nd, 3rd, 7th, 14th and 28th day after operation were lower than those of blank control group, and the differences were statistically significant (all at P<0.05). The IOP of ILK-siRNA-AAV group was lower on 7th, 14th, 21st and 28th day after operation than those of NC-siRNA-AAV group, with statistically significant differences (all at P<0.05). The bleb survival time of blank control group, NC-siRNA-AAV group, ILK-siRNA-AAV group and MMC group was (3.50±1.51), (5.00±3.41), (31.50±3.15) and (31.33±2.46) days, respectively, with a significant difference among them ( F=395.83, P<0.05). The bleb survival time of ILK-siRNA-AAV group and MMC group was higher than that of blank control group and NC-siRNA-AAV group, and the differences were statistically significant (all at P<0.05). There were statistically significant differences in the relative expression levels of ILK mRNA and protein among four groups ( F=222.32, 752.69; both at P<0.05), and the relative expression levels of ILK mRNA and protein were significantly lower in ILK-siRNA-AAV group than blank control group and NC-siRNA-AAV group, and the differences were statistically significant (all at P<0.05). Proliferative fibrous connective tissue and a large number of cells at surgical sites were found in blank control group and NC-siRNA-AAV group, and the fibroblasts were of a high density and grew in clumps.In ILK-siRNA-AAV group, the bulbar conjunctiva was thin, and the arrangement of fibrous connective tissue was loose, and a few proliferative fibroblasts were found.In MMC group, the conjunctival fibrous layer was loose and thin, forming cavities, and scarce cells were found.There was statistically significant difference in the percentage of collagen fiber positive staining area among four groups ( F=741.66, P<0.05). The positive staining percentage of ILK-siRNA-AAV group and MMC group was significantly lower than that of blank control group, among which there was lower positive staining percentage in ILK-siRNA-AAV group than NC-siRNA-AAV group, and the differences were statistically significant (all at P<0.05). Conclusions:Silencing of ILK can inhibit the scar formation after glaucoma filtering surgery and maintain low IOP in rats.

Research progress in gene therapy for amyotrophic lateral sclerosis / 中华神经科杂志

Amyotrophic lateral sclerosis is a neurodegenerative disease caused by the loss of motor neurons in the brain and spinal cord. There is currently no effective cure. The emergence of gene therapy brings hope to treatment, which can be achieved by delivering transgenes to replace or correct defective genes, as well as the expression of neurotrophic factors. The vectors of gene therapy can be viral vectors and non-viral vectors. Lentiviral vectors can be used to deliver therapeutic sequences to motor neurons in the central nervous system. Adeno-associated viruses can effectively mediate gene expression and delivery of neurotrophic factors. Gene editing and antisense oligonucleotides therapy are also perspective treatment options. This article summarizes gene therapy for amyotrophic lateral sclerosis from basic experiments and clinical trials.

Prokaryotic expression of a recombinant protein of adeno-associated virus capsid conserved regions and preparation of its polyclonal antibody / 南方医科大学学报

OBJECTIVE@#To express and purify the antigenic peptide of adeno-associated virus (AAV) capsid conserved regions in prokaryotic cells and prepare its rabbit polyclonal antibody.@*METHODS@#The DNA sequence encoding the conserved regions of AAV capsid protein was synthesized and cloned into the vector pET30a to obtain the plasmid pET30a-AAV-CR for prokaryotic expression and purification of the conserved peptides. Coomassie blue staining and Western blotting were used to identify the AAV conserved peptides. Japanese big ear white rabbits were immunized with AAV conserved region protein to prepare polyclonal antibody, with the rabbits injected with PBS as the control group. The antibody titer was determined with ELISA, and the performance of the antibody for recognizing capsid protein sequences of AAV1-AAV10 was assessed with Western blotting and immunofluorescence assay.@*RESULTS@#The plasmid pET30a-AAV-CR was successfully constructed, and a recombinant protein with a relative molecular mass of 17000 was obtained. The purified protein induced the production of antibodies against the conserved regions of AAV capsid in rabbits, and the titer of the purified antibodies reached 1:320 000. The antibodies were capable of recognizing a wide range of capsid protein sequences of AAV1-AAV10.@*CONCLUSION@#We successfully obtained the polyclonal antibodies against AAV capsid conserved region protein from rabbits, which facilitate future studies of AAV vector development and the biological functions of AAV.