Surface Modification of Biomimetic PLGA-(ASP-PEG) Matrix with RGD-Containing Peptide:a New Non-Viral Vector for Gene Transfer and Tissue Engineering

RGD-containing peptide （ K16-GRGDSPC） , characterized as non-viral gene vectors, was fabricated to modify the surface of PLGA-[ASP- PEG] matrix, which offered the foundation for gene transfer with porous matrix of gene activated later. Peptide was synthesized and matrix was executed into chips A, B and chip C. Chip C was regarded as control. Chips A and B were reacted with cross-linker. Then chip A was reacted with peptide. MS and HPLC were ased to detect the .14W and purity of peptide. Sulphur, existing on the surface of biomaterials, was detected by XPS. The purity of un-reacted peptide in residual solution was detected by a spectrophotometer. HPLC shows that the peptide purity was 94%- 95% , and MS shows that the MW was 2 741. 3307. XPS reveals that the binding energy of sulphur was 164 eV and the ratio of carbon to sulphur （C/S） was 99. 746 ：0. 1014 in reacted chip A. The binding energy of sulphur in reacted chip B was 164 eV and 162 eV, C/ S was 99.574：0.4255, aM there was no sulphur in chip C. Peptide was manufactured and linked to the surface of biomimetic and 3-D matrix, which offered the possibilities for gene transfer and tissue engineering with this new kind of non-viral gene vector.

MicroRNA-regulated viral vectors for gene therapy

Safe and effective gene therapy approaches require targeted tissue-specific transfer of a therapeutic transgene.Besides traditional approaches, such as transcriptional and transductional targeting, micro RNA-dependent posttranscriptional suppression of transgene expression has been emerging as powerful new technology to increase the specificity of vector-mediated transgene expression. Micro RNAs are small non-coding RNAs and often expressed in a tissue-, lineage-, activation- or differentiation-specific pattern. They typically regulate gene expression by binding to imperfectly complementary sequences in the 3' untranslated region(UTR) of the m RNA. To control exogenous transgene expression, tandem repeats of artificial micro RNA target sites are usually incorporated into the 3' UTR of the transgene expression cassette, leading to subsequent degradation of transgene m RNA in cel s expressing the corresponding micro RNA. This targeting strategy, first shown for lentiviral vectors in antigen presenting cells, has now been used for tissue-specific expression of vector-encoded therapeutic transgenes, to reduce immune response against the transgene, to control virus tropism for oncolytic virotherapy, to increase safety of live attenuated virus vaccines and to identify and select cell subsets for pluripotent stem cell therapies, respectively. This review provides an introduction into the technical mechanism underlying micro RNA-regulation, highlights new developments in this field and gives an overview of applications of micro RNA-regulated viral vectors for cardiac, suicide gene cancer and hematopoietic stem cell therapy, as well as for treatment of neurological and eye diseases.

纳米粒子在骨组织工程化基因修饰治疗中的应用

背景:传统的骨组织工程技术治疗临界骨缺损存在成骨效率低、安全性差等问题。而以非病毒纳米粒子为基因载体构建的基因强化型骨组织工程移植物,具有更高的成骨效率和安全性,引起了国内外学者的广泛关注和研究。目的:对当前国内外有关纳米粒子在组织工程成骨基因治疗研究中取得的新技术、新方法以及面临的挑战等进行综述,旨在为纳米粒子介导的骨组织工程基因治疗研究提供参考。方法:第一作者在Pub Med、Web of Science和中国知网数据库上进行文献检索,并以“Bone defect repair,Bone tissue engineering,Gene delivery,Nanoparticles,Non-viral gene vector,Sustained release technology,Sequential release,Targeted delivery”作为英文检索词,以“骨缺损修复,骨组织工程,基因递送,纳米粒子,非病毒基因载体,缓释技术,序贯释放,靶向递送”作为中文检索词,最终纳入84篇文献进行总结。结果与结论:(1)在骨缺损愈合的各个生理阶段进行针对性的基因递送可以显著增强骨修复效果。在早期炎症阶段,通过纳米粒子递送抗炎基因来调节炎症反应,可以为后续骨愈合奠定基础;在血管新生期,向局部递送促血管化基因有助于形成高度组织化、可灌注的血管系统,加快骨愈合速度;随着血管化的进行,骨骼的神经再支配也开始发生,此时递送促神经再生的功能性基因有利于促进神经化骨再生;在成骨阶段,通过构建纳米粒子-成骨基因复合物,可以直接提升支架及体内新骨形成的效率。(2)各种有机、无机纳米颗粒、金属有机框架和外泌体等非病毒纳米载体,在骨组织工程基因治疗中具有巨大的潜力,这些纳米基因载体各有其独特的优势和不足,因此在实际应用时,需要根据基因转染效率、生物安全性和成骨特性等因素选择最合适的类型。(3)为了全面提升递送基因的效果,目前主要通过对纳米载体进行各种功能设计来增强基因转染效率,包括增强缓释性和多基因递送序贯性等时间调控能力、增强对骨组织和成骨相关细胞的空间靶向能力、增强跨膜运输效率和细胞核靶向能力等全过程调控手段。(4)未来要进一步推动纳米粒子介导的骨组织工程基因治疗在临床上的应用,还需要克服诸多技术挑战,包括提高有机纳米基因载体的基因转染效率、降低无机纳米载体的生物安全性风险、优化新型纳米载体的生产工艺以及促进其它生理过程与成骨交互作用等,这些问题也是未来骨组织工程基因治疗的研究热点和潮流。

Differentially expressed genes in hepatocellular carcinoma induced by woodchuck hepatitis B virus in mice

INTRODUCTIONHepatocellular carcinoma(HCC)is one of the major causes of death in the word.The mechanism of carcinogenesis is unknown,although it is widely accepted that HBV and HCV are clsely related to liver cancer[1-5[1-5].Previously,a variety of studies have described the differences in gene expression which distinguished tumor from nontumor[6-11].Cloning of the genes,especially the genes associated with HBV and HCV,is still very important to account for the development of liver cancer.

Expression and significance of HBV genes and their antigens in human primary intrahepatic cholangiocarcinoma

AIM To explore the etiology and pathogenesis of human primary intrahepatic cholangiocarcinoma, the expression of HBV genes and HBV-antigens was detected in the cancerous tissue and its surrounding hepatic tissues.METHODS HBV-antigens were detected by immunohistochemical technique and HBV genes were examined with in situ hybridization.RESULTS In 20 cases of cholangiocarcinoma, the positive detection rate of HBxAg, pre-S1, pre-S2, HBsAg and HBcAg was 75%, 40%, 40%, 10% and 0%, respectively, and in the surrounding hepatic tissues of 19 cases the positive rates were 84.2%, 47.9%, 47.9%, 31.6% and 31.6%. Among 40 cases of cholangiocarcinoma, the positive rate of HBV-DNA, x gene, pre-s gene, s gene and s gene fell on 77.5%, 70.0%, 47.5%, 40% and 42.5%, respectively, and of the surrounding hepatic tissues in 33 cases, 87.9%, 84.8%, 63.6%, 69.7% and 66.7%.CONCLUSION The development of human primary intrahepatic cholangiocarcinoma bears a close relationship with chronic persistent HBV infection. Particularly, the x gene of HBV and its protein (HBxAg) might play an important role in pathogenesis of hepatic carcinoma.A large number of studies indicate a close relationship between human primary hepatocellular carcinoma and hepatitis B virus (HBV) infection, which is considered generally as an important factor in the development of hepatic carcinoma[1,2]. In human primary hepatic carcinoma, hepatocellular carcinoma is more frequently encountered, while intrahepatic cholangiocarcinoma (ChC), including hepatocholangiocarcinoma (HChC), is relatively less, being 8%-10%[3]. For a long time, the etiology and pathogenesis of intrahepatic cholangiocarcinoma have been unclear. A few reports considered it to be related to infestation with clonorchiasis sinensis[4,5], but never involved with HBV infection. We used immunohistochemical technique and in situ hybridization methods to detect HBV genes and their -related antigens in the tissues of intrahepatic cholangiocarcinoma and its surrounding hepatic tissues for the purpose of exploring the etiology and pathogenesis of intrahepatic cholangiocarcinoma.

Cloning and expression of core gene cDNA of Chinese hepatitis C virus in cosmid pTM3

AIM To clone core gene cDNA of Chinesehepatitis C virus(HCV)into eukaryoticexpression vector cosmid pTM3 and to expressHCV core antigen in HepG2 cells.METHODS Core gene cDNA of HCV wasintroduced into eukaryotic expression vectorcosmid pTM3.Using vaccinia virus/bacteriophage T7 hybrid expression system,HepG2 cells were transfected with therecombinant plasmid pTM3-Q534 by lipofectin.RESULTS From the transfected bacteriaTop10F’,2 pTM3-Q534 clones containing therecombinant plasmid were identified fromrandomly selected 10 ampicillin-resistantcolonies.By reverse transcription PCR andindirect immunofluorescence technique,HCVRNA and core protein was identified in HepG2cells transfected with the recombinant plasmid.CONCLUSION The construction of arecombinant plasmid and the expression of coregene cDNA of HCV in HepG2 was successful.

Cloning of the non-structural gene 3 of hepatitis C virus and its inducible expression in cultured cells

AIM To study the inducible expression of hepatitis C virus ns3 gene (HCV ns3) in eukaryotic cells.METHODS The ns3 gene was obtained from plasmid pBns3 by polymerase chain reaction and inserted into the cloning vector pGEM-T. Then, the ns3 was subcloned into the vector pMSG to generate dexamethasone (DM)-inducible expression plasmid pMSG-ns3. CHO cells were transfected by pMSG-ns3 using calcium phosphate precipitation method and cultivated for 12 h-24 h. The transfected cells were induced with DM and the transient expression of NS3 protein was analyzed by ELISA and Western-blot methods.RESULTS After treated with 3×10-8mol/ L DM, the expression of NS3 was observed in the transfected CHO cells. A slightly higher level of NS3 was shown along with the time of DM treatment.CONCLUSION The inducible expressing vector pMSG-ns3 might be helpful for further studies of the characteristics of the ns3 gene in vivo.

Sequencing of PCR amplified HBV DNA pre-c and c regions in 2.2.15 cells and antiviral action by targeted antisense oligonucleotide directed against sequence

AIM To study the specific inhibition of HBV gene expression by liver-targeting antisense oligonucleotide (ASON) directed against pre-c and c regious in a sequence-specific manner.METHODS According to the result of direct sequencing of PCR amplified products, a 16-mer phosphorothioate analogue of the antisense oligonucleotide (PS-ASOn) directed against the HBV U5-like region was synthesized and then linked with one live-targeting ligand, the galactosylated poly-L-lysine. Their effect on the expression of HBV gene was observed using the 2.2.15 cells.RESULTS HBV DNA in the 2.2.15 cells was from HBV with surface antigen subtype ayw1 by sequencing so that antisense oligonucleotides could bind specifically to the target sequence through base piring. Under the same experimental conditions, the inhibitory rates of PS-ASON to HBsAg and HBeAg were 70% and 58% at a concentration of 10μmol/L, while by ligand-PS-ASON they were 96% and 82%, the amount of HBV DNA in cultured supernatant and cells was reduced significantly. An unrelated sequence oligonucleotide showed no effectiveness. All the oligonucleotides had no cytotoxicity.CONCLUSION Antisense oligonucleotides complexed by the liver-targeting ligand can be targeted to cells via asialoglycoprotein receptors, resulting in supecific inhibition of HBV gene expression and replication.

Preliminary study on the production of transgenic mice harboring hepatitis B virus X gene

AIM To establish transgenic mice lineage xharboring hepatitis B virus X gene and to provide an efficient animal model for studying the exact role of the HBx gene in the process of hepatocarcinogenesis. METHODS The HBx transgenic mice were produced by microinjecting the construct with X gene of HBV (subtype adr) DNA fragment into fertilized eggs derived from inbred C57 BL/6 strain; transgenic mice were identified by using Nested PCR; expression and phenotype of HBx gene were analyzed in liver from transgenic mice at the age of 8 weeks by RT PCR, pathologic examination and periodic acid schiff staining (PAS), respectively. RESULTS Five hundred and fourteen fertilized eggs of C57 BL/6 mice were microinjected with recombinant retroviral DNA fragment, and 368 survival eggs injected were transferred to the oviducts of 18 pseudopregnant recipient mice, 8 of them became pregnant and gave birth to 20 F1 offspring. Of 20 offsprings, four males and two females carried the hybrid gene (HBx gene). Four male mice were determined as founder, named X1, X5, X9 and X15. These founders were back crossed to set up F1 generations with other inbred C57BL/6 mice or transgenic littermates, respectively. Transmission of HBx gene in F1 offspring of X1, X5 and X9 except in X15 followed Mendelian rules. The expression of HBx mRNA was detected in liver of F1 offspring from the founder mice (X1 and X9), which showed vacuolation lesion and glycogen positive foci. CONCLUSION Transgenic mice harboring HBx gene were preliminarily established.

Cloning of differentially expressed genes in human hepatocellular carcinoma and nontumor liver

INTRODUCTIONThe mechanism of hepatocellular carcinoma(HCC)is still unclear,although some genes have been found to play a role in the transformation of liver cells,and a variety of studies have described differences in gene expression which distinguished tumor from nontumor[1-6].The new genes,especially the functional genes directly related with tumor are still worth being found.The purpose of our study is to find the different genes between human liver tumor and normal tissues using suppression subtractive hybridization.

New gene therapy strategies for hepatic fibrosis

The liver is the largest internal organ of the body, which may suffer acute or chronic injury induced by many factors, leading to cirrhosis and hepatocarcinoma. Cirrhosis is the irreversible end result of fibrous scarring and hepatocellular regeneration, characterized by diffuse disorganization of the normal hepatic structure, regenerative nodules and fibrotic tissue. Cirrhosis is associated with a high co-morbidity and mortality without effective treatment, and much research has been aimed at developing new therapeutic strategies to guarantee recovery. Liver-based gene therapy has been used to downregulate specific genes, to block the expression of deleterious genes, to delivery therapeutic genes, to prevent allograft rejection and to augment liver regeneration. Viral and non-viral vectors have been used, with viral vectors proving to be more efficient. This review provides an overview of the main strategies used in liver-gene therapy represented by non-viral vectors, viral vectors, novel administration methods like hydrodynamic injection, hybrids of two viral vectors and blocking molecules, with the hope of translating findings from the laboratory to the patient′s bed-side.

HBeAg gene expression with baculovirus vector in silk worm cells

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Relationship between HBV genotypes and anti-viral therapeutic efficacy of interferon-alpha

BACKGROUND: Much evidence demonstrates that the genotypes of hepatitis B virus (HBV) present differences in pathogenicity and outcomes owing to differences in genetic structure. This study aimed to investigate the influences of HBV genotypes on the anti-viral therapeutic efficacy of interferon-alpha (IFN-alpha) in chronic hepatitis B patients, and to determine the relationship between HBV genotypes and levels of viral replication or gene variations. METHODS: The chronic hepatitis B patients who were treated with IFN-alpha were selected randomly. Anti-viral therapeutic efficacy was monitored in these patients. The HBV genotypes were detected by PCR microplate hybridization ELISA. The levels of serum HBV-DNA were determined by fluorescence quantitative PCR. HBV gene variation at pre-C and basic core promoter (BCP) regions were assayed by gene chip technology. RESULTS: Genotypes B and C were predominant in 94 chronic hepatitis B patients. A, E and F genotypes were not found in these patients. The HBV-DNA levels of genotype C and mixed genotypes were significantly higher than those of genotype B. The response to IFN-alpha in patients with genotype B was markedly better than in those with genotypes C and D, and the complete response to IFN-alpha was only observed in genotype B. The response to IFN-alpha in patients with mixed genotypes was the least sensitive. The negative transition of HBeAg was correlated with variations in the HBV pre-C and BCP regions in patients with partial or no response to IFN-alpha. The variation rates of HBV pre-C and BCP regions were clearly higher in genotype C than in genotype B. CONCLUSIONS: The results suggest that HBV genotype is correlated with the serum levels of HBV-DNA, HBV gene variations and therapeutic efficacy of IFN-alpha. The regular detection of HBV genotypes in the clinic will be of benefit for disease prognosis and planning of anti-viral therapeutic strategies.

Restoring axonal localization and transport of transmembrane receptors to promote repair within the injured CNS: a critical step in CNS regeneration

Each neuronal subtype is distinct in how it develops,responds to environmental cues,and whether it is capable of mounting a regenerative response following injury.Although the adult central nervous system（CNS） does not regenerate,several experimental interventions have been trialled with successful albeit limited instances of axonal repair.We highlight here some of these approaches including extracellular matrix（ECM） modification,cellular grafting,gene therapy-induced replacement of proteins,as well as application of biomaterials.We also review the recent report demonstrating the failure of axonal localization and transport of growth-promoting receptors within certain classes of mature neurons.More specifically,we discuss an inability of integrin receptors to localize within the axonal compartment of mature motor neurons such as in the corticospinal and rubrospinal tracts,whereas in immature neurons of those pathways and in mature sensory tracts such as in the optic nerve and dorsal column pathways these receptors readily localize within axons.Furthermore we assert that this failure of axonal localization contributes to the intrinsic inability of axonal regeneration.We conclude by highlighting the necessity for both combined therapies as well as a targeted approach specific to both age and neuronal subtype will be required to induce substantial CNS repair.

Synthesis of N-methylene phosphonic chitosan(NMPCS)and its potential as gene carder

N-Methylene phosphonic chitosan （NMPCS）, an amphiphilic macromolecule with powerful chelating ability of Ca^2＋ ions, was synthesized and characterized. The physicochernical properties of NMPCS and the interactions between NMPCS and plasmid DNA were investigated by FTIR, ^13C NMR, X-ray, agarose gel electrophoresis retardation assay, atomic force microscopy （AFM） and circular dichroism （CD）. The results suggest that at charge ratio 2：1 or above, DNA could be completely entrapped and spherical complexes with mean size of 80-210 nm were formed. Taking HeLa as host cell, luciferase expression mediated by NMPCS improved about 100 times compared to the expression mediated by chitosan.

Use of PEI-coated Magnetic Iron Oxide Nanoparticles as Gene Vectors

Summary: To evaluate the feasibility of using polyethyleneimine (PEI) coated magnetic iron oxide nanoparticles (polyMAG-1000) as gene vectors. The surface characteristics of the nanoparticles were observed with scanning electron microscopy. The ability of the nanoparticles to combine with and protect DNA was investigated at different PH values after polyMAG-1000 and DNA were combined in different ratios. The nanoparticles were tested as gene vectors with in vitro transfection models. Under the scanning electron microscope the nanoparticles were about 100 nm in diameter. The nanoparticles could bind and condense DNA under acid, neutral and alkaline conditions, and they could transfer genes into cells and express green fluorescent proteins (GFP). The transfection efficiency was highest (51 %) when the ratio of nanoparticles to DNA was 1:1 (v:w). In that ratio, the difference in transfection efficiency was marked depending on whether a magnetic field was present or not: about 10 % when it was absent but 51 % when it was present. The magnetic iron oxide nanoparticles coated with PEI may potentially be used as gene vectors.

Gene and cell therapy based treatment strategies for inflammatory bowel diseases

Inflammatory bowel diseases(IBD)are a group of chronic inflammatory disorders most commonly affecting young adults.Currently available therapies can result in induction and maintenance of remission,but are not curative and have sometimes important side effects.Advances in basic research in IBD have provided new therapeutic opportunities to target the inflammatory process involved.Gene and cell therapy approaches are suitable to prevent inflammation in the gastrointestinal tract and show therefore potential in the treatment of IBD.In this review,we present the current progress in the field of both gene and cell therapy and future prospects in the context of IBD.Regarding gene therapy,we focus on viral vectors and their applications in preclinical models.The focus for cell therapy is on regulatory T lymphocytes and mesenchymal stromal cells,their potential for the treatment of IBD and the progress made in both preclinical models and clinical trials.

Synthesis and Evaluation of Novel Chitosan Derivatives for Gene Delivery

A series of novel water soluble chitosan derivatives as gene vectors was synthesized. The delivery systems were tested for their ability to form complexes with plasmid DNA by utilizing agarose gel electrophoresis, particle size analysis, zeta potential measurement and scanning electron microscopy. Furthermore, cytotoxicity of chitosan derivatives and transfection efficiency of polyplexes were evaluated in vitro. The experimental results showed that the novel chitosan derivatives had lower cytotoxicity, good DNA condensation, and higher transfection efficiencies compared to chitosan in both 293T and HeLa cell lines. It was indicated that these chitosan derivatives were promising candidates for non-viral gene vectors.

Characterization of hepatitis B virus X gene quasispecies complexity in mono-infection and hepatitis delta virus superinfection

Hepatitis delta virus(HDV) seems to strongly suppress hepatitis B virus(HBV)replication, although little is known about the mechanism of this interaction. Both these viruses show a dynamic distribution of mutants, resulting in viral quasispecies. Next-generation sequencing is a viable approach for analyzing the composition of these mutant spectra. As the regulatory hepatitis B X protein(HBx) is essential for HBV replication, determination of HBV X gene(HBX)quasispecies complexity in HBV/HDV infection compared to HBV monoinfection may provide information on the interactions between these two viruses.AIM To compare HBV quasispecies complexity in the HBX 5' region between chronic hepatitis delta(CHD) and chronic HBV mono-infected patients.METHODS Twenty-four untreated patients were included: 7/24(29.2%) with HBeAgnegative chronic HBV infection(CI, previously termed inactive carriers), 8/24(33.3%) with HBeAg-negative chronic hepatitis B(CHB) and 9/24(37.5%) with CHD. A serum sample from each patient was first tested for HBV DNA levels.The HBX 5' region [nucleotides(nt) 1255-1611] was then PCR-amplified for subsequent next-generation sequencing(MiSeq, Illumina, United States). HBV quasispecies complexity in the region analyzed was evaluated using incidencebased indices(number of haplotypes and number of mutations), abundancebased indices(Hill numbers of order 1 and 2), and functional indices(mutation frequency and nucleotide diversity). We also evaluated the pattern of nucleotide changes to investigate which of them could be the cause of the quasispecies complexity.RESULTS CHB patients showed higher median HBV-DNA levels [5.4 logIU/mL,interquartile range(IQR) 3.5-7.9] than CHD(3.4 logIU/mL, IQR 3-7.6)(P = n.s.)or CI(3.2 logIU/mL, IQR 2.3-3.5)(P < 0.01) patients. The incidence and abundance indices indicated that HBV quasispecies complexity was significantly greater in CI than CHB. A similar trend was observed in CHD patients, although only Hill numbers of order 2 showed statistically significant differences(CHB2.81, IQR 1.11-4.57 vs CHD 8.87, 6.56-11.18, P = 0.038). There were no significant differences in the functional indices, but CI and CHD patients also showed a trend towards greater complexity than CHB. No differences were found for any HBV quasispecies complexity indices between CHD and CI patients. G-to-A and C-to-T nucleotide changes, characteristic of APOBEC3 G, were higher in CHD and CI than in CHB in genotype A haplotypes, but not in genotype D. The proportion of nt G-to-A vs A-to-G changes and C-to-T vs T-to-C changes in genotype A and D haplotypes in CHD patients showed no significant differences. In CHB and CI the results of these comparisons were dependent on HBV genotype.CONCLUSION The lower-replication CHD and CI groups show a trend to higher quasispecies complexity than the higher-replication CHB group. The mechanisms associated with this greater complexity require elucidation.

HIGN LEVEL EXPRESSION OF HEPATITIS C VIRUS CORE GENE IN E.COLI

Objective To express the hepatitis C virus (HCV) core gene in E . coli on a high level. Methods The cDNA coding for HCV core protein was amplified by polymerase chain reaction (PCR). The PCR product was purified and digested with restriction enzymes and inserted into the downstream of P RP L promoter of a high level expression vector pBV220 . HCV core gene was expressed in E . coli in a non fused form. The expression protein was analysed by SDS PAGE , and its immunoactivity was tested by ELISA . Results Sequence analysis of the amplified PCR products confirmed that we have successfully cloned and expresssed the intact core protein of HCV. SDS PAGE showed that a specific protein with a molecular weight of 21kDa at a level of 14.0% of the total bacterial proteins appeared in bacteria harboring pBV/HCVCore, while this protein was absent in the control bacteria harboring pBV220. The results of enzyme immunoassay analysis showed that this protein could be specifically recognized by the HCV positive sera from patients with hepatitis C .Conclusion The intact HCV core protein was successfully expressed in  E . coli  in a non fused form on a high level, and its immunoactivity was high.