Transmission of porcine endogenous retrovirus in xenotransplantation / 器官移植

Organ transplantation is the most effective treatment for various types of end-stage diseases. To resolve the problem of donor shortage in organ transplantation, the possibility of xenotransplantation has been gradually explored by surgeons. Pig is one of the common donor sources for xenotransplantation. As a bridge between two species, the viruses carried by pig organs may be transmitted between species and cause the risk of zoonosis. Porcine endogenous retrovirus (PERV) is integrated into the genome, which is a category of retrovirus featuring cross-species transmission. In this article, the influencing factors of transmission characteristics of PERV, the transmission risk of PERV and its recombinant virus, and the detection and transmission risk assessment of PERV in xenotransplantation test were reviewed, aiming to provide reference for alleviating severe shortage of donor organs and driving the advancement of xenotransplantation technologies.

Protective role of expression of human complement regulatory protein hCD55 in islet xenotransplantation / 器官移植

Objective To validate whether the expression of human cluster of differentiation 55 (hCD55) protein in porcine islet cells could inhibit the activation of complement components in human serum. Methods Four adult pigs with WT (wild type), GTKO [α-1, 3-galactosyltransferase (GGTA1) knockout], GTKO/hCD55 and hCD55 genotypes were selected. Islet cells were isolated from WT, GTKO and GTKO/hCD55 pigs, and the purity and insulin secretion function were detected. The expression of hCD55 at the DNA, RNA and protein levels was analyzed by agarose gel electrophoresis, reverse transcription polymerase chain reaction (RT-PCR) and flow cytometry, respectively. Complement-dependent cytotoxicity assay and complement deposition assay were performed under the incubation conditions with fresh human serum. Results The purity of isolated porcine islet cells from three genotype pigs was > 75%, and the glycemic index was > 1. The expression of hCD55 messenger RNA(mRNA) and protein in GTKO/hCD55 porcine islet cells decreased the deposition of human complement component C3c and membrane-attacking complex C5b-9, and reduced the cytotoxicity. Conclusions The expression of hCD55 protein in porcine islet cells could inhibit the activation of human complement and reduce complement-mediated killing effect, indicating that hCD55 protein could exert complement protection effect on porcine islet cells. These findings provide theoretical basis for the application of hCD55 in islet xenotransplantation.

Exploration of complement-dependent cytotoxicity technology for GTKO/hCD55 genetically engineered pig-to-human xenotransplantation / 中华器官移植杂志

Objective:To compare the inhibitory effect of human CD55(hCD55)expressed on porcine peripheral blood mononuclear cells(PBMC)on rabbit complement-and human complement-dependent cytotoxicity(CDC).Methods:Three α1, 3-galactosyltransferase gene knockout(GTKO)pigs from the same strain were selected.Two were transferred with hCD55 gene.According to the expression level of hCD55, the animals were divided into three groups of GTKO, GTKO/hCD55 Low(low-expression of hCD55)and GTKO/hCD55 High(high-expression of hCD55). After PBMC from these pigs were incubated with complement-inactivated pooled human serum(20 cases), rabbit complement-or human complement-dependent cytotoxicity and binding of antibodies(IgM/G)to pig PBMC were detected by flow cytometry. Results:No significant difference existed in binding of human serum xenoreactive antibodies to PBMC from three groups.The cytotoxicity to GTKO pig PBMC mediated by rabbit complement or human complement were 98.97%±0.50% and 82.73%±3.20% respectively.Both values were quite high.Compared with GTKO group, a low expression of hCD55 had no significant inhibitory effect on rabbit complement-dependent cytotoxicity(97.07%±2.25% vs. 98.9%±0.50%, P=0.2 267) while a high expression of hCD55 exerted a mild inhibitory effect on rabbit complement-dependent cytotoxicity(81.70%±5.86% vs. 98.9%±0.50%, P=0.0 355). Differently, a low expression of hCD55 had a potent inhibitory effect on human complement-dependent cytotoxicity(23.83%±3.53% vs. 82.73%±3.20%, P<0.0 001). Compared with hCD55 low-expression group, a high expression of hCD55 had a further inhibitory effect on human complement-dependent cytotoxicity(2.79%±0.45% vs. 82.73%±3.20%, P=0.009), attaining the level of negative control group.The inhibitory effect of low/high expression of hCD55 on human complement-mediated CDC was significantly better than that on rabbit complement-mediated CDC. Conclusions:Compared with traditional CDC counterpart using rabbit complement, modified CDC technology of commercial standard human complement is recommended for evaluating the regulatory effect of hCD55 expressed on cell surface from GTKO/hCD55 genetically engineered pigs.It thus provides experimental rationales for establishing a novel CDC experimental system of effectively evaluate the function of hCD55 after xenotransplantation.

Transgenic tomato vaccine expressing chimeric protein paca/ctb can immunize rats through gastrointestinal absorption / 中国组织工程研究

BACKGROUND: The transgenic plant anti-caries vaccine has gradually demonstrated its unique advantages due to its simple production process, low price, good immunogenicity, safety and effectiveness, and has become a research focus in recent years. OBJECTIVE: To immunize the Sprague-Dawley rats with transgenic tomatoes carrying chimeric protein of PAcA/CTB by gavage and to observe the immunogenicity and immunoreactivity in the rats. METHODS: Male Sprague-Dawley rats were randomly divided into a positive control group, an experimental group and a negative control group, in which the rats were given deactivated Streptococcus mutans, transgenic tomatoes carrying PAcA/CTB, and normal tomatoes by gavage, respectively, at 1 week after establishment of dental caries models in animals. The intragastric administration was done once a week for 4 continuous weeks. Blood and saliva samples of rats were collected before immunization and 1, 2, 3, and 4 weeks after immunization to detect the levels of IgG and sIgA antibodies against Streptococcus mutans PAcA by ELISA. The upper and lower molars of the rats at the age of 57 days were scored for dental caries. The study protocol was approved by the Laboratory Animal Ethics Committee of Zunyi Medical University. RESULTS AND CONCLUSION: Compared with the negative control group, positive control and experimental groups had a significant increase in the levels of anti-PAcA sIgA in saliva at 1, 2, 3, and 4 weeks after immunization (P < 0.01). Compared with the negative control group, the positive control group showed a significant increased level of anti-PAcA IgG in serum at 1-4 weeks after immunization (P < 0.05), while the experimental group had a significantly increased level of anti-PAcA IgG in serum at 2-4 weeks after immunization (P < 0.01). Tooth damage was minimized, only a few of caries reached the superficial dentin layer, and the number of caries was the least in the positive control group, followed by the experimental group and the negative control group in turn. To conclude, the transgenic tomatoes expressing PAcA/CTB has certain immunogenicity and immunoreactivity which can effectively immunize the rats by gavage and reduce the incidence of dental caries.

Ectopic expression of the AmDREB1F gene from Ammopiptanthus mongolicus enhances stress tolerance of transgenic Arabidopsis / 生物工程学报

Dehydration-responsive element binding proteins (DREBs) are an important class of transcription factors related to plant stress tolerance. Ammopiptanthus mongolicus is an evergreen broadleaf shrub endemic to desert areas of northwest China, and it has a very high tolerance to harsh environments. In order to reveal the functions and mechanisms of the AmDREB1F gene from this species in enduring abiotic stresses, we performed subcellular localization test, expression pattern analysis, and stress tolerance evaluation of transgenic Arabidopsis harboring this gene. The protein encoded by AmDREB1F was localized in the nucleus. In laboratory-cultured A. mongolicus seedlings, the expression of AmDREB1F was induced significantly by cold and drought but very slightly by salt and heat stresses, and undetectable upon ABA treatment. In leaves of naturally growing shrubs in the wild, the expression levels of the AmDREB1F gene were much higher during the late autumn, winter and early spring than in other seasons. Moreover, the expression was abundant in roots and immature pods rather than other organs of the shrubs. Constitutive expression of AmDREB1F in Arabidopsis induced the expression of several DREB-regulated stress-responsive genes and improved the tolerance of transgenic lines to drought, high salinity and low temperature as well as oxidative stress. The constitutive expression also caused growth retardation of the transgenics, which could be eliminated by the application of gibberellin 3. Stress-inducible expression of AmDREB1F also enhanced the tolerance of transgenic Arabidopsis to all of the four stresses mentioned above, without affecting its growth and development. These results suggest that AmDREB1F gene may play positive regulatory roles in response to abiotic stresses through the ABA-independent signaling pathways.

Molecular cloning and functional characterization of CmFT (FLOWERING LOCUS T) from Cucumis melo L.

CmFT homologous gene in muskmelon was obtained by homologous cloning, introducing CmFT gene by Agrobacteriummediated transformation. The results of subcellular localization showed that CmFT protein was expressed in cytoplasm and nucleus. qRTPCR results showed that the expression levels of AtLFY, AtFT, AtCO, AtFLC, AtSOC1 and AtAP1 were upregulated in the 35S::MeFT Arabidopsis line. The CmFT gene was introduced into wild-type Arabidopsis by Agrobacterium-mediated transformation, and the growth status of T2 transgenic Arabidopsis thaliana and wild-type A. thaliana was observed. The results showed that wild-type Arabidopsis began to bolt on the 25th day after sowing, we can initially confirm that the FT gene of melon can promote the early flowering of melon in the growth and development of melon.

Experimental study on transplantation of microencapsulated transgenic bone marrow mesenchymal stem cells for early steroid-induced osteonecrosis of femoral head in rabbits / 中国修复重建外科杂志

Objective: To investigate the effect of microencapsulated transgenic bone marrow mesenchymal stem cells (BMSCs) transplantation on early steroid induced osteonecrosis of femoral head (SONFH) in rabbits. Methods: Alginate poly- L-lysine-sodium alginate (APA) microencapsulated transgenic BMSCs with high expression of Foxc2 were prepared by high-voltage electrostatic method. Part of the cells were cultured in osteoblasts and observed by alizarin red staining at 2 and 3 weeks. Forty New Zealand white rabbits were used to prepare SONFH models by using hormone and endotoxin. Thirty two rabbits who were successful modeling were screened out by MRI and randomly divided into 4 groups (groups A, B, C and D, n=8); another 6 normal rabbits were taken as normal control (group E). The rabbits in group A did not receive any treatment; and in groups B, C, and D were injected with normal saline, allogeneic BMSCs, and APA microencapsulated transgenic BMSCs respectively after core decompression. At 6 and 12 weeks after operation, specimens of femoral head were taken for HE staining to observe bone ingrowth; the expressions of osteocalcin (OCN), peroxisome proliferative activated receptor γ 2 (PPARγ-2), and vascular endothelial growth factor (VEGF) proteins were observed by immunohistochemistry staining. At 12 weeks after operation, the bone microstructure was observed by transmission electron microscope, and the maximum compressive strength and average elastic modulus of cancellous bone and subchondral bone were measured by biomechanics. Results: After 2 and 3 weeks of induction culture, alizarin red staining showed the formation of calcium nodules, and the number of calcium nodules increased at 3 weeks when compared with 2 weeks. The rabbits in each group survived until the experiment was completed. Compared with groups A, B, and C, the trabeculae of group D were more orderly, the empty bone lacunae were less, there were abundant functional organelles, and obvious osteogenesis was observed, and the necrotic area was completely repaired at 12 weeks. Immunohistochemical staining showed that, at 6 and 12 weeks after operation, the expressions of OCN and VEGF in groups A, B, and C were significantly lower than those in groups D and E, while those in groups B and C were significantly higher than those in group A, and in group E than in group D ( P0.05). Conclusion: In vivo transplantation of microencapsulated transgenic BMSCs can repair early SONFH in rabbits.

Gene therapy: An updated overview on the promising success stories

@#Gene therapy is a method of treatment of disease aimed at its molecular level. The progress of gene therapy, however, was as promising as it was tardy mainly due to the limitations in the resources and financial part of its development as well as owing to the rarity of most diseases it can offer its benefits to. The methods of gene therapy can vary depending on factors such as the physiology of tissue of interest, affinity of vectors to a certain type of cells, depth and accessibility of the tissue of interest, and size of the gene to be replaced or edited. The concept behind gene therapy has inspired scientists and clinicians alike leading to a rapid expansion of its clinical utility that has become so widespread to not only include diseases of monogenic origin, but also polygenic diseases, albeit not so commonly. This article delves into notable success stories of gene therapy which has been regarded as the beacon of medical novelty expected to blossom in the near future to provide a holistic, targeted, precise, and individualistic personalised-medicine as well as laying out the future hopes of gene therapy in the treatment of debilitating diseases such as solid tumours, AIDS, Tuberculosis, Diabetes Mellitus, psychiatric illnesses, which are still at a standstill, from a gene therapy point of view

Gene stacking as a strategy to confer characteristics of agronomic importance in plants by genetic engineering / Empilhamento gênico como estratégia para conferir características de importância agronômica em plantas via engenharia genética

ABSTRACT: Gene stacking refers to the introduction of two or more transgenes of agronomic interest in the same plant. The main methods for genetically engineering plants with gene stacking involve (i) the simultaneous introduction, by the co-transformation process, and (ii) the sequential introduction of genes using the re-transformation processes or the sexual crossing between separate transgenic events. In general, the choice of the best method varies according to the species of interest and the availability of genetic constructions and preexisting transgenic events. We also present here the use of minichromosome technology as a potential future gene stacking technology. The purpose of this review was to discuss aspects related to the methodology for gene stacking and trait stacking (a gene stacking strategy to combine characteristics of agronomical importance) by genetic engineering. In addition, we presented a list of crops and genes approved commercially that have been used in stacking strategies for combined characteristics and a discussion about the regulatory standards. An increased number of approved and released gene stacking events reached the market in the last decade. Initially, the most common combined characteristics were herbicide tolerance and insect resistance in soybean and maize. Recently, commercially available varieties were released combining these traits with drought tolerance in these commodities. New traits combinations are reaching the farmer's fields, including higher quality, disease resistant and nutritional value improved. In other words, gene stacking is growing as a strategy to contribute to food safety and sustainability.

RESUMO: O empilhamento gênico se refere a introdução de dois ou mais transgenes de interesse agronômico na mesma planta. Os principais métodos de produção de plantas geneticamente modificadas com empilhamento gênico envolvem (i) a introdução simultânea, pelo processo de co-transformação, e (ii) a introdução sequencial de genes, pelos processos de re-transformação ou por cruzamento entre eventos transgênicos. Em geral, a escolha do melhor método varia de acordo com a espécie de interesse e a disponibilidade de construções genéticas e eventos transgênicos preexistentes. Também é apresentado aqui o uso da tecnologia de minicromossomos como tecnologia potencial de empilhamento gênico. O objetivo desta revisão é discutir aspectos relacionados à metodologia para o empilhamento de genes a combinação de características (obtida via empilhamento de genes de interesse agronômico) via engenharia genética. Além de discutir, é apresentado uma lista de culturas e genes aprovados comercialmente que tem sido usado em estratégias de empilhamento e uma discussão sobre normas regulatórias. Um número maior de eventos com empilhamento de genes foi aprovado e liberado no mercado na última década. Inicialmente, a combinação das características de tolerância a herbicidas e resistência a insetos era a mais popular, principalmente em soja e milho. Recentemente, estas características combinadas com tolerância a seca nessas culturas foram liberadas comercialmente. Novas características combinadas estão entrando na lavoura, incluindo aumento da qualidade, resistência a doenças e aumento do valor nutricional. Em outras palavras, o empilhamento gênico está crescendo como tecnologia para contribuir para a segurança alimentar e sustentabilidade.

Regulatory framework of genome-edited products - a review / 生物工程学报

Genome editing is a genetic engineering technique that uses site-directed cleavage activity of specific artificial nucleases and endogenous DNA damage repair activity to generate insertions, deletions or substitutions in the targeted genomic loci. As the accuracy and efficiency of genome editing is improving and the operation is simple, the application of genome editing is expanding. This article provides an overview of the three major genome editing technologies and genome editing types, and the regulatory frameworks for genome-edited products were summarized in the United States, the European Union, and other countries. At the same time, based on the Chinese safety management principles and systems for genetically modified organisms (GMOs), the authors proposed a regulatory framework for genome-edited products. Genome-edited products should first be classified according to whether containing exogenous genetic components such as Cas9 editing enzymes or not. They should be regulated as traditional genetically modified organisms if they do. Otherwise, the regulation of genome-edited products depends on targeted modifications.

Application progress of transgenic mouse models of corneal neovascularization / 国际眼科杂志(Guoji Yanke Zazhi)

@#The invasion of the cornea by capillary or lymphatic vessels leads to corneal neovascularization and if not handled in time, it will seriously affect vision, the establishment and application of transgenic mouse models of corneal neovascularization provides a good platform for the study of corneal neovascularization mechanism, the screening of antiangiogenic drugs and the evaluation of treatments. Transgenic mouse model of corneal neovascularization is a very valuable and potential animal model. This paper mainly introduces the application of transgenic mouse models in the research of corneal neovascularization.

Effect of GC-rich DNA fragment on the level of transgene expression in Chinese hamster ovary cells and its position effect / 新乡医学院学报

Objective To analyze the effect of GC-rich DNA fragments on the level of transgenic expression in Chinese hamster ovary (CHO) celts and its position effect.Methods The synthetic DNA fragment with GC-rich was cloned into the 5'or 3'or both 5'and 3'ends of expression cassette of expression vector.Three new expression vectors (pIRES-G1,pIRES-G2 and pIRES-G3) which was inserted with the GC-rich DNA fragments in different position were transfected CHO ceils,respectively,and then was observed under fluorescence microscope;the control vector was pIRES-EGFP.Stable transfected cell lines were screened under G418,and enhanced green fluorescent protein(EGFP) expression was analyzed by flow cytometry and the transgenic copy number was detected by quantitative real-time quantitative polymerase chain reaction (qRT-PCR).Results Three expression vectors with a GC-rich DNA fragments in different position were constructed successfully.The insertion of GC-rich DNA fragments at 3'end and both 5',3'ends of the box of expression vector could obviously improve the expression level of vector in CHO cells;and the expression level of the stably transfected CHO cells increased 1.39 fold and 1.32 fold compared to the control vector,respectively;the transgene copy number increased 1.32 fold and 1.24 fold compared with the control vector.While the insertion of GC-rich DNA fragments at 5'end of expression cassette had no obvious effect on the level of gene expression.Conclusion The role of DNA fragment with GC-rich in improving the transgenic expression of CHO cells is related to its position in the vector.The insertion of GC-rich DNA fragments at 3'end and both 5',3'ends of the box of expression vector can improve transgenic expression.

Influence of different promoters on expression of transgene containing MAR expression vector in recombinant CHO cells / 重庆医学

Objective To investigate the effect of different promoters on the expression level of transgene containing MAR expression vector in recombinant CHO cells.Methods The CMV promoter and 3-globin MAR were amplified by PCR,then CMV promoter was replaced the SV40 promoter in pCAT1 for constructing the expression vector droved by CMV promoter.The control vectors of pCAT1 and pCAT2 without containing MAR were simultaneously transfected into the CHO cells.Then the stably transfected cell line was screened by G418.The CAT gene expression level was analyzed by ELISA.Results The expression level of CAT enzyme in the cells transfected with MAR-containing vectors was increased compared with the cells transfected by pCATG and pCAT3 vectors without containing MAR,which were increased by 1.75 and 1.25 times respectively(P＜0.05);but CAT enzyme expression level in the pCAT1 transfected cells droved by SV40 promotor with the MAR-containing expression vectors was 1.4 times higher than that in the pCAT2 vector droved by the CMV promoter(P＜0.05).Conclusion MAR can enhance the transgene expression level in stably recombinant CHO cells,and the promoting efficiency of SV40 promoter and MAR combination is superior to that of CMV promoter and MAR combination.

Establishment of an Alb-cre/DTR mouse model of inducible liver injury / 中国实验动物学报

Objective To analyze the Alb-cre/DTR mouse phenotype, and establish a model of induced liver damage to serve basic researches of liver diseases.Methods The introduced Alb-cre and DTR mice were crossed to obtain Alb-cre/DTR mice and the genomic DNAs were extracted from the tail tissue of the mice for genotying by PCR.Diphtheria toxin was intraperitoneally(i.p.)injected into the Alb-cre/DTR mice, then the body weights were monitored and the sera were collected for the detection of serum ALT and AST levels.Results By crossing Alb-cre and DTR mice we obtained the Alb-cre and DTR double transgenic mouse.The intraperitoneal injection of diphtheria toxin in a dose of 0.625 ng/g body weight significantly induced liver injury in these mice, as showed by the elevated levels of ALT and AST, the gross appearance of liver damage and the pathological changes such as necrosis in the liver tissue.Conclusions We have ob-tained a novel mouse strain of Alb-cre/DTR by crossing Alb-cre and DTR mice.Liver damages in those Alb-cre/DTR mice can be induced by injection of diphtheria toxin.This established mouse model of inducible liver damage is a useful platform for the studies of liver damage and recovery, as well as liver transplantation.

Construction of RNA interference vector of Polygonum cuspidatum chalcone synthase gene and its genetic transformation / 中草药

Objective: To construct the RNAi expression vector of Polygonum cuspidatum chalcone synthase (PcCHS1) gene, and to obtain the transgenic plants in which PcCHS1 expression was down-regulated. Methods: According to known sequence (EF090604) of PcCHS1 gene in GenBank, right primers were designed and the conserved sequence was cloned. The conserved fragment (574 bp) targeting at PcCHS1 gene was inserted into the expression vector pYLRNAi in both forward and reverse directions, and RNA interference (RNAi) expression vector pYLRNAi-PcCHS1 was constructed. Using the method of Agrobacterium-mediated transformation, the expression vector was used to transform the shoot tips of P. cuspidatum, and transgenic plants were obtained. The expression of PcCHS1 was confirmed by Northern blotting and the accumulation of polydatin was detected by HPLC. Results: RNAi expression vector of PcCHS1gene was constructed successfully, and five transgenic plants were obtained. Northern blotting analyses indicated that the expression levels of PcCHS1 were significantly down-regulated in the transgenic plants. Polydatin concentration in the transgenic plants was up to 3.8 times higher than that in non-transformed control plants. Conclusion: Transgenic P. cuspidatum plants with down-regulated expression of PcCHS1 gene were obtained successfully. The content of polydatin in the transgenic P. cuspidatum was significantly increased by RNAi against PcCHS1. This work might establish an experimental basis for the effective application of PcCHS1 in improving polydatin accumulation in P. cuspidatum.

Establishment of a transgenic zebrafish line with tdTomato expression in the ultraviolet-sensitive cone photoreceptors / 中国实验动物学报

Objective To better understand the mechanisms of cone opsin transport , we set to generate a trans-genic zebrafish line with red fluorescence proteins expressing in the cone photoreceptors .Methods We used sws1 promot-er to drive the expression of a chimerical protein , in which the last 44 amino acids of rhodopsin of Xenopus laevis were fused to the C-terminus of tdTomato to restrict its localization to the outer segment of photoreceptors .Results We successfully i-solated such a transgenic zebrafish line and confirmed the localization of tdTomato by immunostaining analysis .Conclu-sions This transgenic zebrafish line will help us to better understand the transport mechanisms of cone opsins , especially the transport in live photoreceptors .

Application of zebrafish ( Danio rerio) in the fields of environmental ecotoxicology and environmental monitoring / 中国实验动物学报

Zebrafish, a new type of model animal , has been widely used in many fields of biological research be-cause of its low cost , ability of external fertilization , high fecundity , allowance of embryo transplant , and ectogenesis .Re-cently, zebrafish and its embryos have been widely used in ecotoxicological studies and environmental monitoring .Further-more, with the maturation of zebrafish transgenic techniques , a new era has come for environmental pollution monitoring .

Establishment of cholesteryl ester transfer protein transgenic rabbits by DNA microinjection and analysis of their biological properties / 中国实验动物学报

Objective The aim of this study was to generate human cholesteryl ester transfer protein ( CETP) transgenic rabbits and analyze their biological properties.Methods We generated human CETP transgenic rabbits by DNA microinjection, and detected the expression of human CETP by real-time PCR and Western blot assay.The activity of CETP was measured using an activity assay kit.Results Human CETP transgenic rabbits were successfully generated by DNA microinjection.Compared with wide type rabbits, the expression of human CETP was dramatically increased in the liver of the human CETP transgenic rabbits.The plasma CETP activity was also much higher in the liver of human CETP transgenic rabbits than that of control rabbits.Conclusions The model of human CETP transgenic rabbits is successfully established by DNA microinjection.It will provide a useful tool for the studies of CETP biological function and its involvement in the mechanisms of cardiovascular diseases.

A Gene and Neural Stem Cell Therapy Platform Based on Neuronal Cell Type-Inducible Gene Overexpression

PURPOSE: Spinal cord injury (SCI) is associated with permanent neurological damage, and treatment thereof with a single modality often does not provide sufficient therapeutic outcomes. Therefore, a strategy that combines two or more techniques might show better therapeutic effects. MATERIALS AND METHODS: In this study, we designed a combined treatment strategy based on neural stem cells (NSCs) introduced via a neuronal cell type-inducible transgene expression system (NSE::) controlled by a neuron-specific enolase (NSE) promoter to maximize therapeutic efficiency and neuronal differentiation. The luciferase gene was chosen to confirm whether this combined system was working properly prior to using a therapeutic gene. The luciferase expression levels of NSCs introduced via the neuronal cell type-inducible luciferase expression system (NSE::Luci) or via a general luciferase expressing system (SV::Luci) were measured and compared in vitro and in vivo. RESULTS: NSCs introduced via the neuronal cell type-inducible luciferase expressing system (NSE::Luci-NSCs) showed a high level of luciferase expression, compared to NSCs introduced via a general luciferase expressing system (SV::Luci-NSCs). Interestingly, the luciferase expression level of NSE::Luci-NSCs increased greatly after differentiation into neurons. CONCLUSION: We demonstrated that a neuronal cell type-inducible gene expression system is suitable for introducing NSCs in combined treatment strategies. We suggest that the proposed strategy may be a promising tool for the treatment of neurodegenerative disorders, including SCI.

Plant prebiotics and human health: Biotechnology to breed prebiotic-rich nutritious food crops

Microbiota in the gut play essential roles in human health. Prebiotics are non-digestible complex carbohydrates that are fermented in the colon, yielding energy and short chain fatty acids, and selectively promote the growth of Bifidobacteria and Lactobacillae in the gastro-intestinal tract. Fructans and inulin are the best-characterized plant prebiotics. Many vegetable, root and tuber crops as well as some fruit crops are the best-known sources of prebiotic carbohydrates, while the prebiotic-rich grain crops include barley, chickpea, lentil, lupin, and wheat. Some prebiotic-rich crop germplasm have been reported in barley, chickpea, lentil, wheat, yacon, and Jerusalem artichoke. A few major quantitative trait loci and gene-based markers associated with high fructan are known in wheat. More targeted search in genebanks using reduced subsets (representing diversity in germplasm) is needed to identify accessions with prebiotic carbohydrates. Transgenic maize, potato and sugarcane with high fructan, with no adverse effects on plant development, have been bred, which suggests that it is feasible to introduce fructan biosynthesis pathways in crops to produce health-imparting prebiotics. Developing prebiotic-rich and super nutritious crops will alleviate the widespread malnutrition and promote human health. A paradigm shift in breeding program is needed to achieve this goal and to ensure that newly-bred crop cultivars are nutritious, safe and health promoting.