Sonic hedgehog delivered by an adeno-associated virus protects dopaminergic neurones against 6-OHDA toxicity in the rat

Summary. Direct intracerebral administration of sonic hedgehog (SHH) reduces 6-OHDA and MPTP toxicity to nigral dopaminergic cells in rats and primates. To determine whether transfection of the DNA sequence for SHH using viral vectors also protects against 6-OHDA toxicity, a type 2 adeno- associated virus (AAV) incorporating 600 base pairs of N-terminal SHH DNA was generated to induce SHH expression in rat striatum.AAV-SHH was injected into the striatum, 3 weeks prior to the initiation of an unilateral partial 6-OHDA nigro-striatal lesion. Animals receiving 4×10⁷ viral particles of AAV-SHH showed a reduction in (+)-amphetamine induced ipsilateral turning over 4 weeks, when compared to animals receiving vehicle or a LacZ encoding vector. Following vehicle or AAV-LacZ administration, 6-OHDA caused a marked loss of striatal dopamine content and nigral tyrosine hydroxylase (TH) immunopositive cells. Following treatment with 4×10⁷ viral particles of AAV-SHH the loss of striatal dopamine content was reduced and there was marked preservation of nigral dopaminergic cells. However, administration of 4×10⁸ particles of AAV-SHH did not cause a significant change in (+)-amphetamine-induced rotation, striatal dopamine levels or the number of nigral TH immunoreactive cells following 6-OHDA lesioning compared to vehicle or AAV-LacZ treated animals.The results show that SHH delivered via a viral vector can protect dopaminergic neurons against 6-OHDA toxicity and suggest that this could be developed into a novel treatment for PD. However, the effects maybe dose limited due to uncoupling of hedgehog receptor signalling at higher levels of SHH expression.Present address: Synta Pharmaceuticals Corp., Lexington, MA, USA     

靶向敲减KLF4基因的重组腺相关病毒载体的构建及其在肺动脉高压动物模型中的应用

目的 构建靶向敲减KLF4基因的重组腺相关病毒载体,并应用于肺血管疾病,为后期研究肺血管KLF4基因敲减在肺动脉高压大鼠中的作用及相关分子机制奠定基础。方法 根据大鼠KLF4基因序列,设计针对大鼠特异性的siRNA序列,以pHBAAV-U6-MCS-CMV-EGFP作为空白载体,通过酶切技术构建带有GFP荧光标记的KLF4干扰腺病毒载体pHBAAV-r-KLF4 shRNA-GFP,行测序分析,并进行病毒扩增、纯化及滴度测定。本研究对长时间（3个月）接触香烟烟雾的大鼠进行气道注入AAV1-KLF4-shRNA的干预治疗,观察大鼠右心室收缩压、平均右心室压等血流动力学指标改变。结果 经测序检测显示,大鼠AAV1-KLF4-shRNA腺相关病毒载体构建成功。健康对照组、生理盐水模型组、对照病毒模型组、治疗干预组的右心室收缩压和平均右心室压比较,差异均有统计学意义（P <0.05）。结论 对长时间接触香烟烟雾的肺动脉高压模型大鼠应用AAV1-KLF4-shRNA腺相关病毒载体,能有效改善右心室收缩压和平均右心室压,该载体在相关疾病动物模型中应用有效,为后期顺利开展AAV1-KLF4-s...     

Recombinant adeno-associated virus vector expressing glial cell line-derived neurotrophic factor reduces ischemia-induced damage

To explore the potential of using the recombinant adeno-associated viral (rAAV) vector, expressing glial cell line-derived neurotrophic factor (GDNF) as the gene therapy for stroke, we injected rAAV vectors expressing GDNF (rAAV-GDNF) into the cortex of rats which had been experiencing transient bilateral common carotid artery ligation and right middle cerebral artery ligation for 90 min. GDNF levels in cortical tissues of rAAV-GDNF-injected animals were significantly higher than in the control animals injected with rAAV-expressing lacZ (rAAV-lacZ), indicating that rAAV can deliver and express the GDNF gene in cortical tissues. Triphenyltetrazolium chloride tissue stain analysis revealed that the rAAV-delivered GDNF gene could rescue the brain tissues from ischemia-induced injury. Cortical tissues which received rAAV-GDNF injections had both significantly smaller total volumes of infarction and smaller areas of infarction on each brain slice than those which were injected with rAAV-lacZ. An in situ labeling analysis demonstrated significantly less apoptotic cells in cortical tissues rescued by rAAV-GDNF, indicating prevention of apoptosis as the mechanism of cortical cell protection. Moreover, immunohistochemistry staining of Neu-N indicated that the rescued brain tissues contained the same number of Neu-N-positive neuronal cells as contralateral undamaged brain tissues. This provides strong evidence that cortical neuronal cells can be rescued by GDNF gene therapy. Indeed, these findings show that the rAAV is a potential delivery vector of GDNF gene for the therapy of stroke.     

乙型肝炎表面抗原基因重组2型腺相关病毒的免疫原性研究

目的观察含乙型肝炎表面抗原(HBsAg)基因的2型重组腺相关病毒(rAAV-2-HBsAg)在Balb/c小鼠体内的免疫原性。方法以5×1011的重组病毒颗粒单次注射Balb/c小鼠,RT-PCR扩增肝脏组织中HBsAg基因cD-NA:ELISA检测肝组织中HBsAg的表达;RIA法检测血清中表面抗体(抗一HBs)滴度;51Cr释放分析检测细胞毒性T淋巴细胞(CTL)活性。结果外源性HBsAg基因己整合到肝细胞染色体DNA并有效地转录和翻译,表达水平最高可达33.8pg/(mglivertissue),rAAV-HBsAg免疫小鼠后可以诱导机体产生表面抗体并激发特异性CTL。结论外源性HBsAg基因可以转移到小鼠肝细胞并稳定表达;rAAV-2-HBsAg免疫小鼠可以同时诱导体液和细胞免疫反应的出现。提示基于rAAV-2载体的乙型肝炎(HBV)疫苗,对于防止HBV感染,尤其是作为慢性乙型肝炎的治疗性疫苗可能只有潜在的应用价值,值得做进一步的系统研究。     

3种腺相关病毒介导的绿色荧光蛋白对西藏小型猪胚胎成纤维细胞的转染效率

目的比较3种不同血清型腺相关病毒(AAV)介导的绿色荧光蛋白对西藏小型猪胚胎成纤维细胞的转染效率。方法原代分离培养西藏小型猪胚胎成纤维细胞并进行形态学鉴定,按照感染复数(MOI)为103、104、105转染传代两次的猪胚胎成纤维细胞,流式细胞学检测不同血清型AAV对西藏小型猪胚胎成纤维细胞的转染效率,并在倒置显微镜下观察转染后绿色荧光的表达强度;同时,应用MTT方法检测不同血清型AAV对西藏小型猪胚胎成纤维细胞的毒性。结果腺相关病毒AAV2-EGFP对PFF的转染效率随MOI值的增加而增高,MOI为103、104、105时,转染效率分别为(33.68±1.18)%、(50.80±2.59)%和(60.08±1.08)%,而其他两种血清型病毒感染效率均低于AAV2-EGFP。3种病毒转染PFF过程中,细胞生长正常,MTT显示各个转染组与对照组(未转染组)在D570处吸光度无显著差异。结论AAV2血清型载体对体外培养的猪胚胎成纤维细胞的感染效率显著高于其他几种血清型,AAV8和AAV9对PFF感染能力极差,筛选AAV2作为西藏小型猪基因打靶的最适病毒载体;同时,3类血清型病毒载体对猪胚胎成纤维细胞均无明显细胞毒性。     

Identification of the heparin binding site on adeno-associated virus serotype 3B (AAV-3B)

Adeno-associated virus is a promising vector for gene therapy. In the current study, the binding site on AAV serotype 3B for the heparan sulfate proteoglycan (HSPG) receptor has been characterized. X-ray diffraction identified a disaccharide binding site at the most positively charged region on the virus surface. The contributions of basic amino acids at this and other sites were characterized using site-directed mutagenesis. Both heparin and cell binding are correlated to positive charge at the disaccharide binding site, and transduction is significantly decreased in AAV-3B vectors mutated at this site to reduce heparin binding. While the receptor attachment sites of AAV-3B and AAV-2 are both in the general vicinity of the viral spikes, the exact amino acids that participate in electrostatic interactions are distinct. Diversity in the mechanisms of cell attachment by AAV serotypes will be an important consideration for the rational design of improved gene therapy vectors.     

Recombinant adeno-associated virus delivered human thioredoxin-PR39 prevents hypoxia-induced apoptosis of ECV304 cells

Human thioredoxin and antibacterial peptide, PR39, have been shown to have potent antioxidant effects that may prolong survival of cells during hypoxia. The pSSCMV/human thioredoxin-PR39 vector was successfully constructed in this study and used to infect ECV304 cells. Transfected ECV304 cells were incubated at 1%, 5% hypoxic, and normal oxygen conditions. We found that the number of apoptotic cells after transfection with recombinant adeno-associated virus-human thioredoxin -PR39 was significantly lower than controls, suggesting a protective effect of the recombinant human thioredoxin-PR39 protein on hypoxic cells.     

腺相关病毒载体在眼病基因治疗中的应用及研究进展

腺相关病毒(adeno-associated virus,AAV)属微小病毒科,目前有11种血清型。AAV作为基因转移载体具有安全性好、宿主范围广、免疫原性低和携带的治疗基因长期表达等优势而成为眼病基因治疗研究的热点。影响AAV载体在眼部基因转移的因素包括AAV载体的血清型、基因转移途径、组织特异性启动子等。以AAV为载体的基因转移在视网膜疾病、青光眼、角膜病的基因治疗研究中取得了新的进展。     

rAAV介导hBDNF基因转染对急性高眼压兔眼视网膜BDNF表达的影响

目的 通过观察视网膜内源性脑源性神经营养因:F(BDNF)表达的变化,探讨玻璃体注射携带人脑源性神经营养因子(hBDNF)的重组腺伴随病毒(rAAV-BDNF)对急性高眼压兔眼神经损害的保护机制.方法 24只健康日本大耳白兔任选一眼作为造模眼(为模型组,共24眼),用生理盐水前房灌注法造成急性高眼压模型,对侧眼不作任何处理作为正常对照组(24眼).另24只健康日本大耳白兔任选一眼作为造模眼(为BDNF组,共24眼),BDNF组在造模前3d玻璃体内注射10μl rAAV-BDNF.于造模后第1、3、7、14d三组各摘除6只观察眼做病理切片,进行免疫组化染色,观察视网膜内源性BDNF表达.结果 模型组兔眼视网膜内源性BDNF表达阳性细胞数减少,BDNF组兔眼视网膜内源性BDNF表达阳性细胞数较对照组及模型组增加(P<0.05,P<0.01).结论 rAAV-BDNF基因转染通过增加视网膜内源性BDNF的表达起到神经保护作用.玻璃体注射是rAAV-BDNF转染视网膜的有效途径.

Abstract：

Objective To observe the changes in the expression of brain derived neurotrophic factor (BDNF) gene in the retina of rabbits with acute high intraocular pressure (IOP) after injection of recombinant adeno-associated virus (rAAV) vector containing human BDNF gene (rAAV-hBDNF), and investigate the neuroprotective mechanism of rAAV-hBDNF. Methods The unilateral eyes of 24 white rabbits were randomly chosen as the model group with high IOP induced by saline perfusion into the anterior chamber, and the contralateral eyes served as the control group without treatment. In another 24 white rabbits, 10 μl rAAV-BDNF was injected into the vitreous body of one of the eyes 3 days before induction of high IOP. On days 1,3,7, and 14 after perfusion, the bilateral eyes of 6 rabbits were excised for immunohistochemistry for the expression of endogenous BDNF gene in the retina. Results The number of BDNF-positive cells in the retina decreased after induction of high IOP, and injection of rAAV-hBDNF resulted in a significant increase in BDNF-positive cells as compared with the positive cell number in the high IOP model and control groups (P<0.05, P<0.01). Conclusion rAAV-mediated BDNF gene transfection can increase endogenous BDNF expression in the retina of rabbits with acute high IOP. Intravitreous injection is an effective pathway for rAAV-hBDNF gene transfection into the retina.     

HIF-1α siRNA Leads to Apoptosis of Pancreatic Cancer Cells under Hypoxic Conditions

OBJECTIVE To explore the role of hypoxic inducible factor-1α(HIF-1α) in the proliferation and apoptosis of pancreatic cancer cells under hypoxic conditions.METHODS A cassette encoding small interference RNA (siRNA)targeting HIF-1α mediated by recombinant adeno-associated virus (rAAV) was constructed, giving rAAV-siHIF, rAAV-siHIF or rAAV- hrGFP was transfected into exponentially growing MiaPaCa2 cells under hypoxic conditions. Then, the expression of HIF-1αmRNA and protein, the proliferation and apoptosis of MiaPaCa2 cells were examined, using real-time PCR, Western Blot, MTT and TUNEL, respectively.RESULTS Under hypoxic conditions, rAAV-siHIF inhibited the expression of HIF-1α mRNA and protein in MiaPaCa2 cells. At the same time, rAAV-siHIF decreased MiaPaCa2 cell proliferation and induced apoptosis. However, rAAV-hrGFP had no effect on the expression of HIF-1α as well as the proliferation and apoptosis of MiaPaCa2 cells under hypoxic conditions.CONCLUSION Under hypoxic conditions, HIF-1α plays a key role in the proliferation of MiaPaCa2 cells, and inhibition of HIF-1α expression can lead to MiaPaCa2 cell apoptosis.