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Find video protocols related to scientific articles indexed in Pubmed.
Expression of Cre Recombinase in Alveolar Epithelial Cells of the AQP2-Cre Transgenic Mini-Pigs.
Cell. Physiol. Biochem.
PUBLISHED: 09-10-2014
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Background/Aims: Optimal use of Cre mediated recombination in conditional animal models depends on well characterized Cre driver lines. Unfortunately, some Cre driver lines exhibit unexpected expression patterns hindering their utility in Cre/loxP systems. Thus, systematic assessment of new Cre lines is essential for generating useful Cre driver lines for future studies. Methods: Here, we describe a Cre Transgenic (Tg) mini-pig line in which the expression of Cre is directed by a 3-kb 5' fragment of the kidney-specific aquaporin 2 (AQP2); however, the AQP2-Cre Tg mini-pig line exhibits expression of Cre in alveolar epithelial cells (AECs) instead of collecting duct cells. The specificity of the AQP2-Cre plasmid was validated in vitro, and indicating that the AQP2-Cre was specifically expressed in the transfected LLC-PK1 cells. Absolute quantitative real-time PCR (qRT-PCR) and inverse PCR were performed to determine the copy numbers and integration sites of the AQP2-Cre transgene. Relative qRT-PCR was performed to evaluate variation in Cre expression levels over time. Results: Our data indicated that this AQP2-Cre Tg mini-pig line exhibits stable expression of Cre recombinase over time and in subsequent generations, even though the AQP2-Cre transgene was segregated and reduced in subsequent generations. Conclusion: Combined with our previous studies of the activity of this Cre, we conclude that this Cre Tg mini-pig line will provide a reliable tool for generating lung-specific gene targeting mini-pig models, thereby allowing the investigation of gene functions in lung development and studying the molecular mechanisms of human lung disease. © 2014 S. Karger AG, Basel.
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Inhibition of HMG-CoA reductase increases the expression of IFN-responsive genes.
Clin. Exp. Pharmacol. Physiol.
PUBLISHED: 08-12-2014
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The HMG-CoA reductase (HMGCR) pathway is an important metabolic route that is present in almost every organism. However, whether HMGCR affects the expression of IFN-responsive genes is unclear. In this study, expression levels of IFN-responsive genes were monitored by real time PCR and ELISA. The results showed that expression levels of IFN-responsive genes were significantly increased in HMGCR-downregulated cells and HMGCR inhibitor-treated cells, indicating that inhibition of HMGCR activates the expression of IFN-responsive genes. The result in this study will give new insight into the role of HMG-CoA reductase in antiviral research. This article is protected by copyright. All rights reserved.
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DNA methylation-mediated silencing of neuronatin (NNAT) in pig parthenogenetic fetuses.
Gene
PUBLISHED: 07-18-2014
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It is generally believed that aberrant expression of imprinted genes participates in growth retardation of mammalian parthenogenesis. Neuronatin (NNAT), a paternally expressed gene, plays important roles in neuronal growth and metabolic regulation. Here we have compared the gene expression and promoter methylation pattern of NNAT between pig normally fertilized (Con) and parthenogenetic (PA) embryos. The results showed loss of NNAT expression (p<0.001) and hypermethylation of NNAT promoter in PA samples. Additionally, partial methylation was observed in Con fetuses, while almost full methylation and unmethylation of NNAT promoter were apparent in Metaphase II (MII) oocytes and mature sperms, respectively, which identified the CpG promoter region as a putative differentially methylated region (DMR) of NNAT. The data demonstrate that promoter hypermethylation is associated with the silencing of NNAT in pig PA fetuses, which may be related to developmental failure of pig parthenogenesis at early stages.
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Analysis of molecular variation in porcine reproductive and respiratory syndrome virus in China between 2007 and 2012.
Virol Sin
PUBLISHED: 04-23-2014
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In the present study, 89 porcine reproductive and respiratory syndrome virus (PRRSV) isolates in China during 2007 to 2012 were randomly selected from the GenBank genetic sequence database. Evolutionary characteristics of these isolates were analyzed based on the sequences of non-structural protein 2 (Nsp2) and glycoprotein 5 (GP5). The genetic variations of the isolates were also compared with six representative strains. The results showed that a high degree of genetic diversity exists among the PRRSV population in China. Highly pathogenic PRRSV isolates, with a discontinuous deletion of a 30 amino acid residue in the Nsp2 region, remained the most dominant virus throughout 2007-2012 in China. Owing to the extensive use of representative vaccine strains, natural recombination events occurred between strains. Three isolates - HH08, DY, and YN-2011 - were more closely related to vaccine strains than the other isolates. Both YN-2011 and DY were the evolutionary products of recombination events between strains SP and CH-1R. The results of the present study provide useful information for the epidemiology of PRRSV as well as for vaccine development.
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Nitro-oleic acid downregulates lipoprotein-associated phospholipase A2 expression via the p42/p44 MAPK and NF?B pathways.
Sci Rep
PUBLISHED: 04-11-2014
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Nitro-oleic acid (OA-NO2), acting as anti-inflammatory signaling mediators, are involved in multiple signaling pathways. Lipoprotein-associated phospholipase A2 (Lp-PLA2) is well known as a cardiovascular risk biomarker. Our results showed that OA-NO2 downregulated the expression of Lp-PLA2 in a time- and dose-dependent manner, whereas native OA had no such effect. Furthermore, OA-NO2 could repress Lp-PLA2 expression in the peripheral blood mononuclear cells of apo CIII-transgenic (apo CIII TG) pigs, which exhibited higher Lp-PLA2 expression and activity than did wild-type (WT) pigs. OA-NO2 inhibited Lp-PLA2 expression in macrophages, independent of nitric oxide formation and PPAR?-activation. However, OA-NO2 downregulates Lp-PLA2 by inhibiting the p42/p44 mitogen-activated protein kinase (MAPK) and the nuclear factor ?B (NF?B) pathways. When used to mediate anti-inflammatory signaling, the regulation of inflammatory cytokines and SOD by OA-NO2 might be associated with the reduction of Lp-PLA2. These results suggested that OA-NO2 might exert a vascular-protective effect partially via Lp-PLA2 inhibition.
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Pathogenesis and regulation of cellular proliferation in acute lymphoblastic leukemia - the role of Ikaros.
J BUON
PUBLISHED: 03-25-2014
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Acute lymphoblastic leukemia (ALL) is the most common type of leukemia of childhood. Over the last 50 years there have been tremendous scientific advances in understanding the pathogenesis and the mechanisms that control cellular proliferation in ALL. These discoveries led to the development of efficient therapeutic regimens that greatly improved survival of children with ALL. Recently, several genes have been demonstrated to play a key role in tumor suppression and that their deregulation leads to malignant transformation and can affect overall survival. This review summarizes the role of Ikaros (IKZF1) in tumor suppression and regulation of gene expression in leukemia. Deletions and/or mutations of Ikaros have been detected in a large percentage of pediatric and adult ALL and reduced Ikaros function has been associated with poor outcome in ALL. Ikaros function in chromatin remodeling and epigenetic regulation of gene transcription emphasizes the important role of this protein in controlling cellular proliferation. In this review, we particularly focus on the role of signaling pathways in the regulation of Ikaros activity and its transcriptional control in leukemia.
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HMG-CoA reductase is negatively associated with PCV2 infection and PCV2-induced apoptotic cell death.
J. Gen. Virol.
PUBLISHED: 03-18-2014
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We examined the role of HMG-CoA reductase (HMGCR) during porcine circovirus 2 (PCV2) infection. The results demonstrated that levels of endogenous HMGCR were not significantly different in PCV2-infected cells and mock-infected cells. However, the level of phosphorylated HMGCR, an inactivated form of HMGCR, was increased in PCV2-infected cells. Furthermore, HMGCR was upregulated by overexpression, silenced by siRNA or inactivated using its dominant-negative form in PK-15 cells. The results showed that PCV2 infection was inhibited by HMGCR overexpression, whereas it was significantly increased in HMGCR-silenced cells and HMGCR inhibitor-treated cells. Moreover, there was a robust apoptotic response at 48 h post-infection (p.i.) in HMGCR-inactivated cells, and this response was significantly greater than that observed in PK-15 cells. A modest apoptotic response was also observed in HMGCR-silenced cells. Caspase-3 activity was also analysed in PCV2-infected cells at 48 h p.i. As expected, caspase-3 activity was significantly increased in HMGCR-inactivated and -silenced cells compared with PK-15 cells. PCV2 replication was dose-dependently increased in HMGCR-inactivated cells when treated with increasing amounts of caspase-3 inhibitor. Altogether, HMGCR was negatively associated with PCV2 infection and PCV2-induced apoptotic cell death. These data demonstrated that HMGCR can be used as a candidate target for PCV2 disease control and antivirus research. Furthermore, the cells generated in this study can be used to evaluate the potential effects of HMGCR on PCV2 replication.
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Genomic imprinting analysis of Igf2/H19 in porcine cloned fetuses using parthenogenetic somatic cells as nuclear donors.
Biotechnol. Lett.
PUBLISHED: 02-28-2014
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To gain insight into parthenogenesis in pigs, we report for the first time that using parthenogenetic somatic cells as nuclear donors (PSCNT), the porcine parthenogenetic fetus can develop to gestational day 39. Weight and morphological analysis revealed that PSCNT fetuses were smaller and developmentally retarded when compared to normally fertilized controls. Quantitative gene expression analysis indicated that in PSCNT fetuses, H19 was over-expressed, whereas Igf2 was significantly reduced (p < 0.05) compared with their controls. In addition, bisulfite-sequencing PCR results demonstrated that H19 differentially DNA methylated regions (DMRs) were hypomethylated in PSCNT fetuses, while Igf2 DMRs were hypermethylated in both PSCNT and control fetuses. Our results suggest that extended development of the porcine parthenogenetic fetus can be accomplished using PSCNT and that abnormal DNA methylation of H19 DMRs might contribute to the critical barrier of parthenogenesis in pigs.
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Protein Phosphatase 1 (PP1) and Casein Kinase II (CK2) regulate Ikaros-mediated repression of TdT in thymocytes and T-cell leukemia.
Pediatr Blood Cancer
PUBLISHED: 02-25-2014
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Ikaros is a DNA-binding protein that acts as master-regulator of hematopoiesis and a tumor suppressor. In thymocytes and T-cell leukemia, Ikaros negatively regulates transcription of terminal deoxynucleotide transferase (TdT), a key protein in lymphocyte differentiation. The signaling pathways that regulate Ikaros-mediated repression of TdT are unknown. Our previous work identified Casein Kinase II (CK2) and Protein Phosphatase 1 (PP1) as regulators of Ikaros DNA binding activity. Here, we investigated the role of PP1 and CK2 in regulating Ikaros-mediated control of TdT expression.
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Elevated expression of vascular endothelial growth factor (VEGF) 120 in parthenogenetic porcine placentas.
Biotechnol. Lett.
PUBLISHED: 02-21-2014
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Most mammalian parthenogenetic embryos are unable to develop to term due to placental defects, potentially caused by decreased vasculogenesis and angiogenesis of the parthenogenetic placenta. Here we have compared the expression status of vascular endothelial growth factor (VEGF) and angiopoietin family members between normally developing and parthenogenetic porcine placentas. The result showed significantly reduced expression of these genes but elevated expression of VEGF 120 in the parthenogenetic porcine placenta (p < 0.05). We postulate that the abnormal expression levels of VEGF and angiopoietin family members and, especially, the elevated expression of VEGF 120 observed in parthenogenetic porcine placentas are related to the early miscarriage of parthenogenetic embryos in pigs.
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Construction and expression of mutagenesis strain of aroG gene from Escherichia coli K-12.
Int. J. Biol. Macromol.
PUBLISHED: 02-17-2014
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3-Deoxy-d-arabino-heptulonate-7-phosphate (DAHP) synthase is one of the key enzymes, which catalyzes the first step in the aromatic amino acid biosynthetic pathway and yields the three amino acids tyrosine (Tyr), tryptophan (Typ), and phenylalanine (Phe). In Escherichia coli (E. coli), three differently regulated DAHP synthases carry out the first regulated step in the aromatic amino acid biosynthetic pathway. The three DAHP synthases encoded by the genes aroG, aroF, and aroH are inhibited by phenylalanine, tyrosine and tryptophan, respectively. In this work, the aroG gene was cloned and mutated by site-directed mutagenesis using overlap extension PCR (SOE-PCR) technique. The feedback-resistant DAHP synthase encoded by aroG was achieved by replacing the residue Pro150 of aroG with Leu as to increase net carbon flow down the common pathway. SDS-PAGE and Western blots were used to assess the protein expression level of aroGM which showed the strain harboring the mutated aroGM150 gene achieving over-expression compared to the strain containing an empty plasmid pET-28b((+)).
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Expression, purification and antibody preparation using different constructs of PCV2 capsid protein.
Int. J. Biol. Macromol.
PUBLISHED: 01-20-2014
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Capsid protein (Cap) of porcine circovirus 2 (PCV2) contained critical epitopes for inducing a protective immune response. Here, different fragments of PCV2 Cap protein were cloned, expressed, purified and used to raise polyclonal antibodies. The result showed the recombinant plasmids expressed efficiently in the prokaryotic system. Western blot and ELISA showed the recombinant protein had antigenicity and immunogenicity. Furthermore, efficiency of different constructs to produce antibody against PCV2 was compared. Reactivity and specificity of the polyclonal antibody were characterized by Western blot and indirect immunofluorescent assays. The results indicated that polyclonal antiserum prepared from protein ?Cap17-233 had better reactivity and specificity against PCV2 in comparison to that of protein ?Cap51-233 and the inactivated vaccine. These results will contribute to further studies focusing on the gene and vaccine development against PCV2.
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Sequence-specific inhibition of microRNA via CRISPR/CRISPRi system.
Sci Rep
PUBLISHED: 01-13-2014
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Here, we report a convenient and efficient miRNA inhibition strategy employing the CRISPR system. Using specifically designed gRNAs, miRNA gene has been cut at a single site by Cas9, resulting in knockdown of the miRNA in murine cells. Using a modified CRISPR interference system (CRISPRi), inactive Cas9 can reversibly prevent the expression of both monocistronic miRNAs and polycistronic miRNA clusters. Furthermore, CRISPR/CRISPRi is also capable of suppressing genes in porcine cells.
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Spatiotemporal control of porcine p65RHD expression by advanced Tet-On system in PIEC cells helps regulate NF?B activity.
Mol. Biol. Rep.
PUBLISHED: 01-03-2014
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NF?B transcription activation leads to malfunction of endothelial cells, which is the main reason for pig xenograft rejection. Overexpression of a dominant negative mutant of porcine NF?B p65 (pp65RHD) could inhibit NF?B activation in endothelial cells. This study presents an advanced tetracycline-regulated system for pp65RHD spatiotemporal expression in porcine iliac endothelial cell line. In this system, an endothelial specific promoter ICAM-2 is used to improve pTet-On and internal ribosome entry site as well as enhanced green fluorescent protein (EGFP) elements are used to facilitate the result observation in pTRE-Tight. Through transfection and drug selection, we obtained 7 single cell clones containing the advanced Tet-On system, in which pp65RHD expression is under tight regulated by doxycycline and can be visualized easily through EGFP. The distribution of induced pp65RHD was verified by immunocytochemical assays test. Then, NF?B activity was tested. Luciferase reporter assays showed that NF?B activity in two clones was influenced by the Dox-induced pp65RHD expression, but other clones weren't influenced. Therefore, we picked up 2 cell clones from the uninfluenced clones for further investigation by immunocytochemical assays and RT-PCR detection. The final results supported the overexpression of pp65RHD in one clone could successfully inhibit NF?B activity. The success of pp65RHD spatiotemporal expression system is helpful to regulate NF?B activity and conquer cell-mediated immunity and could be used for preparation of transgenic pig, contributing to xenotransplantation.
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Production of transgenic pigs over-expressing the antiviral gene Mx1.
Cell Regen (Lond)
PUBLISHED: 01-01-2014
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The myxovirus resistance gene (Mx1) has a broad spectrum of antiviral activities. It is therefore an interesting candidate gene to improve disease resistance in farm animals. In this study, we report the use of somatic cell nuclear transfer (SCNT) to produce transgenic pigs over-expressing the Mx1 gene. These transgenic pigs express approximately 15-25 times more Mx1 mRNA than non-transgenic pigs, and the protein level of Mx1 was also markedly enhanced. We challenged fibroblast cells isolated from the ear skin of transgenic and control pigs with influenza A virus and classical swine fever virus (CFSV). Indirect immunofluorescence assay (IFA) revealed a profound decrease of influenza A proliferation in Mx1 transgenic cells. Growth kinetics showed an approximately 10-fold reduction of viral copies in the transgenic cells compared to non-transgenic controls. Additionally, we found that the Mx1 transgenic cells were more resistant to CSFV infection in comparison to non-transgenic cells. These results demonstrate that the Mx1 transgene can protect against viral infection in cells of transgenic pigs and indicate that the Mx1 transgene can be harnessed to develop disease-resistant pigs.
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Efficiency of porcine somatic cell nuclear transfer - a retrospective study of factors related to embryo recipient and embryos transferred.
Biol Open
PUBLISHED: 11-15-2013
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The successful generation of pigs via somatic cell nuclear transfer depends on reducing risk factors in several aspects. To provide an overview of some influencing factors related to embryo transfer, the follow-up data related to cloned pig production collected in our laboratory was examined. (i) Spring showed a higher full-term pregnancy rate compared with winter (33.6% vs 18.6%, P?=?0.006). Furthermore, a regression equation can be drawn between full-term pregnancy numbers and pregnancy numbers in different months (y?=?0.692x-3.326). (ii) There were no significant differences detected in the number of transferred embryos between surrogate sows exhibiting full-term development compared to those that did not. (iii) Non-ovulating surrogate sows presented a higher percentage of full-term pregnancies compared with ovulating sows (32.0% vs 17.5%, P?=?0.004; respectively). (iv) Abortion was most likely to take place between Day 27 to Day 34. (v) Based on Life Table Survival Analysis, delivery in normally fertilized and surrogate sows is expected to be completed before Day 117 or Day 125, respectively. Additionally, the length of pregnancy in surrogate sows was negatively correlated with the average litter size, which was not found for normally fertilized sows. In conclusion, performing embryo transfer in appropriate seasons, improving the quality of embryos transferred, optimizing the timing of embryo transfer, limiting the occurrence of abortion, combined with ameliorating the management of delivery, is expected to result in the harvest of a great number of surviving cloned piglets.
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Multipotent mesenchymal stem cells from human subacromial bursa: potential for cell based tendon tissue engineering.
Tissue Eng Part A
PUBLISHED: 08-21-2013
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Rotator cuff injuries are a common clinical problem either as a result of overuse or aging. Biological approaches to tendon repair that involve use of scaffolding materials or cell-based approaches are currently being investigated. The cell-based approaches are focused on applying multipotent mesenchymal stem cells (MSCs) mostly harvested from bone marrow. In the present study, we focused on characterizing cells harvested from tissues associated with rotator cuff tendons based on an assumption that these cells would be more appropriate for tendon repair. We isolated MSCs from bursa tissue associated with rotator cuff tendons and characterized them for multilineage differentiation in vitro and in vivo. Human bursa was obtained from patients undergoing rotator cuff surgery and cells within were isolated using collagenase and dispase digestion. The cells isolated from the tissues were characterized for osteoblastic, adipogenic, chondrogenic, and tenogenic differentiation in vitro and in vivo. The results showed that the cells isolated from bursa tissue exhibited MSCs characteristics as evidenced by the expression of putative cell surface markers attributed to MSCs. The cells exhibited high proliferative capacity and differentiated toward cells of mesenchymal lineages with high efficiency. Bursa-derived cells expressed markers of tenocytes when treated with bone morphogenetic protein-12 (BMP-12) and assumed aligned morphology in culture. Bursa cells pretreated with BMP-12 and seeded in ceramic scaffolds formed extensive bone, as well as tendon-like tissue in vivo. Bone formation was demonstrated by histological analysis and immunofluorescence for DMP-1 in tissue sections made from the scaffolds seeded with the cells. Tendon-like tissue formed in vivo consisted of parallel collagen fibres typical of tendon tissues. Bursa-derived cells also formed a fibrocartilagenous tissue in the ceramic scaffolds. Taken together, the results demonstrate a new source of MSCs with a high potential for application in tendon repair.
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The generation of transgenic mice with fat1 and fad2 genes that have their own polyunsaturated fatty acid biosynthetic pathway.
Cell. Physiol. Biochem.
PUBLISHED: 07-21-2013
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Microorganisms and higher plants possess their own omega-3 and omega-6 polyunsaturated fatty acid (PUFAs) biosynthetic pathways. The n-6 fatty acid desaturase gene fad-2 codes for the n-6 desaturase enzyme that coverts oleic acid (OA 18:1 n-9) into linoleic acid (LA 18:2 n-6). The n-3 fatty acid desaturase gene fat-1 codes for the n-3 desaturase enzyme that converts n-6 PUFAs into n-3 PUFAs. Mammals lack n-3 and n-6 desaturase enzymes; therefore, they must obtain their omega-3 and omega-6 fatty acids by consuming plants or seafood. The beneficial effects of n-3 and n-6 PUFAs on human development and cardiovascular health have been well documented.
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Generation of AQP2-Cre transgenic mini-pigs specifically expressing Cre recombinase in kidney collecting duct cells.
Transgenic Res.
PUBLISHED: 06-16-2013
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The important differences in physiological parameters and anatomical characteristics of the kidney between humans and mice make it difficult to replicate the precise progression of human renal cystic diseases in gene modification mouse models. In contrast to mice, pigs are a better animal model of human diseases, as they are more similar in terms of organ size, structure, and physiological parameters. Here, we report the generation and initial examination of an AQP2-Cre transgenic (Tg) Chinese miniature (mini)-pig line that expresses Cre recombinase exclusively in kidney collecting duct cells. An 8-kb fragment of the mini-pig aquaporin 2 (AQP2) 5-flanking region was utilized to direct Cre expression in Tg mini-pigs. Two Tg mini-pigs were generated by pig somatic cell nuclear transfer and both carried the entire coding sequence of Cre recombinase. RT-PCR and western blotting analysis revealed that Cre recombinase was uniquely expressed in the kidney, while immunohistochemical studies located its expression in kidney collecting duct cells. Furthermore, six integration sites and 12-14 copies of the Cre gene were detected in various tissues by high-efficiency thermal asymmetric interlaced PCR and absolute quantitative real-time PCR, respectively. Combined with previous studies of Cre recombinase activity, we believe that this AQP2-Cre Tg mini-pig line will be a useful tool to generate kidney collecting duct cell-specific gene knockout mini-pig models, thereby allowing the investigation of gene functions in kidney development and the mechanisms of human renal cystic disease.
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Aberrant expression of Igf2/H19 in porcine parthenogenetic fetuses and placentas.
Anim. Reprod. Sci.
PUBLISHED: 04-02-2013
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The aberrant expression of imprinted genes induces parthenogenetic fetal and placental dysplasia, thus leading to failures in embryonic development. Igf2 and H19 are co-expressed in endoderm and mesoderm-derived tissues and play an important role in normal embryo and extraembryonic development. In this study, the expression and methylation of Igf2/H19 in porcine parthenogenetic fetuses and placentas which had grown 28 days was examined first time to further characterize mammalian parthenogenesis. Weight and morphological comparisons were conducted between parthenogenetic embryos on Day 28 and normal fertilized embryos (control). The results indicated that parthenogenetic fetuses and placentas had smaller weights and volumes than those of the control. In addition, quantitative RT-PCR (qRT-PCR) analysis was performed to determine Igf2/H19 expression levels, showing that the expression of H19 was up-regulated, while Igf2 expression was almost undetectable in both parthenogenetic fetuses and placentas. As a potential mechanism underlying this disrupted expression, the methylation of Igf2/H19 DMR3 was detected using bisulfite sequencing PCR analysis, which revealed the significant hypomethylation of DMR3 in parthenogenetic fetuses and placentas. These results suggest that disruption of Igf2/H19 expression in parthenogenetic fetuses and placentas contributes to implantation failure and/or abortion in swine parthenogenesis, which might be associated with differential methylation patterns in the imprinting control region of imprinted genes.
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Porcine CD4 promoters and enhancers can direct foreign gene expression in human cells.
Biotechnol. Lett.
PUBLISHED: 03-12-2013
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Porcine CD4 proximal promoter and enhancer sequences were cloned and aligned with the corresponding human and murine sequences. The alignment showed nucleotide homology between porcine and human sequences was 62.4 % for the CD4 promoter and 56.6 % for the CD4 enhancer. The nucleotide homology between porcine and murine sequences was 42.5 % for the CD4 promoter and 25.4 % for the CD4 enhancer. The proximal enhancer and promoter regions of the CD4 gene from porcine, murine and human cells were compared for their ability to direct foreign gene expression in transiently transfected human cell lines. The results indicated the porcine CD4 promoters and enhancers could effectively direct expression of a foreign gene in human cells. The porcine promoter was equally efficient as CMV and EF-1? in directing gene expression.
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Moderate expression of Wnt signaling genes is essential for porcine parthenogenetic embryo development.
Cell. Signal.
PUBLISHED: 01-02-2013
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Parthenogenetic embryos are invariably lost in mid-gestation, possibly due to the lack of the paternal genome and the consequent induction of aberrant gene expression. Wnt signaling is essential for embryonic development; however, the studies of this pathway in porcine parthenogenetic embryos have been limited. Here, the role of Wnt signaling in porcine parthenogenetic embryos was studied. In vivo embryos were used as controls. Single cell quantitative real-time PCR showed that Wnt signaling was down-regulated in porcine parthenogenetic embryos. Furthermore, immunofluorescence staining and real-time PCR demonstrated that porcine parthenogenetic embryo development was largely unaffected by the inhibition of Wnt signaling with IWP-2, but blastocyst hatching and trophectoderm development was blocked. In addition, parthenogenetic blastocyst hatching was improved by the activation of Wnt signaling by BIO. However, the developmental competency of porcine embryos, including blastocyst hatching, was impaired and apoptosis was induced upon the excessive activation of Wnt signaling. These findings constitute novel evidence that Wnt signaling is important for porcine pre-implantation development and that its down-regulation may lead to the low hatching rate of porcine parthenogenetic blastocysts.
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Expression of plant sweet protein brazzein in the milk of transgenic mice.
PLoS ONE
PUBLISHED: 01-01-2013
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Sugar, the most popular sweetener, is essential in daily food. However, excessive sugar intake has been associated with several lifestyle-related diseases. Finding healthier and more economical alternatives to sugars and artificial sweeteners has received increasing attention to fulfill the growing demand. Brazzein, which comes from the pulp of the edible fruit of the African plant Pentadiplandra brazzeana Baill, is a protein that is 2,000 times sweeter than sucrose by weight. Here we report the production of transgenic mice that carry the optimized brazzein gene driven by the goat Beta-casein promoter, which specifically directs gene expression in the mammary glands. Using western blot analysis and immunohistochemistry, we confirmed that brazzein could be efficiently expressed in mammalian milk, while retaining its sweetness. This study presents the possibility of producing plant protein-sweetened milk from large animals such as cattle and goats.
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Characterization of a hypertriglyceridemic transgenic miniature pig model expressing human apolipoprotein CIII.
FEBS J.
PUBLISHED: 11-23-2011
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Hypertriglyceridemia has recently been considered to be an independent risk factor for coronary heart disease, in which apolipoprotein (Apo)CIII is one of the major contributory factors, as it is strongly correlated with plasma triglyceride levels. Although ApoCIII transgenic mice have been generated as an animal model for the study of hypertriglyceridemia, the features of lipoprotein metabolism in mice differ greatly from those in humans. Because of the great similarity between pigs and humans with respect to lipid metabolism and cardiovascular physiology, we generated transgenic miniature pigs expressing human ApoCIII by the transfection of somatic cells combined with nuclear transfer. The expression of human ApoCIII was detected in the liver and intestine of the transgenic pigs. As compared with nontransgenic controls, transgenic pigs showed significantly increased plasma triglyceride levels (83 ± 36 versus 38 ± 4 mg·dL(-1), P < 0.01) when fed a chow diet. Plasma lipoprotein profiling by FPLC in transgenic animals showed a higher peak in large-particle fractions corresponding to very low-density lipoprotein/chylomicrons when triglyceride content in the fractions was assayed. There was not much difference in cholesterol content in FPLC fractions, although a large low-density lipoprotein peak was identified in both nontransgenic and transgenic animals, resembling that found in humans. Further analysis revealed markedly delayed clearance of plasma triglyceride, accompanied by significantly reduced lipoprotein lipase activity in post-heparin plasma, in transgenic pigs as compared with nontransgenic controls. In summary, we have successfully generated a novel hypertriglyceridemic ApoCIII transgenic miniature pig model that could be of great value for studies on hyperlipidemia in relation to atherosclerotic disorders.
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Histone deacetylase inhibitor significantly improved the cloning efficiency of porcine somatic cell nuclear transfer embryos.
Cell Reprogram
PUBLISHED: 10-26-2011
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Valproic acid (VPA), a histone deacetylase inbibitor, has been shown to generate inducible pluripotent stem (iPS) cells from mouse and human fibroblasts with a significant higher efficiency. Because successful cloning by somatic cell nuclear transfer (SCNT) undergoes a full reprogramming process in which the epigenetic state of a differentiated donor nuclear is converted into an embryonic totipotent state, we speculated that VPA would be useful in promoting cloning efficiency. Therefore, in the present study, we examined whether VPA can promote the developmental competence of SCNT embryos by improving the reprogramming state of donor nucleus. Here we report that 1?mM VPA for 14 to 16?h following activation significantly increased the rate of blastocyst formation of porcine SCNT embryos constructed from Landrace fetal fibroblast cells compared to the control (31.8 vs. 11.4%). However, we found that the acetylation level of Histone H3 lysine 14 and Histone H4 lysine 5 and expression level of Oct4, Sox2, and Klf4 was not significantly changed between VPA-treated and -untreated groups at the blastocyst stage. The SCNT embryos were transferred to 38 surrogates, and the cloning efficiency in the treated group was significantly improved compared with the control group. Taken together, we have demonstrated that VPA can improve both in vitro and in vivo development competence of porcine SCNT embryos.
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Traditional medicine alpinetin inhibits the inflammatory response in Raw 264.7 cells and mouse models.
Int. Immunopharmacol.
PUBLISHED: 08-21-2011
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Alpinetin, one of the main constituents of the seeds of Alpinia katsumadai Hayata, belonging to flavonoids, has been known to exhibit antibacterial, anti-inflammatory and other important therapeutic activities. The purpose of this study was to investigate the protection of alpinetin on inflammation in Lipopolysaccharide (LPS) stimulated Raw 264.7 cells and LPS induced vivo lung injury model. The effects of alpinetin on pro-inflammatory cytokines and signaling pathways were analyzed by enzyme-linked immunosorbent assay and Western blot. The results showed that alpinetin markedly inhibited the LPS- induced TNF-?, IL-6 and IL-1? production both in vitro and vivo. Furthermore, alpinetin blocked the phosphorylation of I?B? protein, p65, p38 and extracellular signal-regulated kinase (ERK) in LPS stimulated RAW 264.7 cells. From in vivo study, it was also observed that alpinetin attenuated lung histopathologic changes in mouse models. These results suggest that alpinetin potentially decreases the inflammation in vitro and vivo, and might be a therapeutic agent against inflammatory diseases.
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Cell cycle-specific function of Ikaros in human leukemia.
Pediatr Blood Cancer
PUBLISHED: 06-15-2011
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The loss of Ikaros is associated with the development of B and T cell leukemia. Data on Ikaros function, including its role as a tumor suppressor and a regulator of cell cycle progression, come almost exclusively from murine studies; little is known of the mechanisms that regulate human Ikaros function. Our studies are the first to examine the function and regulation of human Ikaros isoforms during the cell cycle in human ALL.
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Vitamin C enhances in vitro and in vivo development of porcine somatic cell nuclear transfer embryos.
Biochem. Biophys. Res. Commun.
PUBLISHED: 06-10-2011
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The reprogramming of differentiated cells into a totipotent embryonic state through somatic cell nuclear transfer (SCNT) is still an inefficient process. Previous studies revealed that the generation of induced pluripotent stem (iPS) cells from mouse and human fibroblasts could be significantly enhanced with vitamin C treatment. Here, we investigated the effects of vitamin C, to our knowledge for the first time, on the in vitro and in vivo development of porcine SCNT embryos. The rate of blastocyst development in SCNT embryos treated with 50?g/mL vitamin C 15h after activation (36.0%) was significantly higher than that of untreated SCNT embryos (11.5%). The enhanced in vitro development rate of vitamin C-treated embryos was associated with an increased acetylation level of histone H4 lysine 5 and higher Oct4, Sox2 and Klf4 expression levels in blastocysts, as determined by real-time PCR. In addition, treatment with vitamin C resulted in an increased pregnancy rate in pigs. These findings suggest that treatment with vitamin C is beneficial for enhancement of the in vitro and in vivo development of porcine SCNT embryos.
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Production of cloned transgenic cow expressing omega-3 fatty acids.
Transgenic Res.
PUBLISHED: 05-25-2011
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n-3 Polyunsaturated fatty acids (n-3 PUFA) are important for human health. Alternative resources of n-3 PUAFs created by transgenic domestic animals would be an economic approach. In this study, we generated a mfat-1 transgenic cattle expressed a Caenorhabditis elegans gene, mfat-1, encoding an n-3 fatty acid desaturase. Fatty acids analysis of tissue and milk showed that all of the examined n-3 PUAFs were greatly increased and simultaneously the n-6 PUAFs decreased in the transgenic cow. A significantly reduction of n-6/n-3 ratios (P<0.05) in both tissue and milk were observed.
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Isolation and culture of embryonic stem-like cells from pig nuclear transfer blastocysts of different days.
Zygote
PUBLISHED: 05-18-2011
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This study was conducted to establish pig embryonic stem (ES)-like cell lines from nuclear transfer blastocysts. A green fluorescent protein (GFP)-expressing cell line was used as the source of donor cells injected into the enucleated oocytes. Blastocysts were collected at D5 (the fifth day), D7 (the seventh day) and D9 (the ninth day). Differential staining was used to assay the viability and development of blastocysts from the 3 days. The number of inner cell mass (ICM) cells increased from 1.83 ± 0.8 (D5) to 5.37 ± 1.2 (D7) to 7.56 ± 1.5 (D9). The expression profiles of embryonic stem (ES) cell factors (OCT4, SOX2, KLF4 and c-MYC) correlated best with the undifferentiated ES state and were identified by qPCR. The expression of the four factors was increased from D5 to D7, whereas the expression decreased from D7 to D9. We tried to isolate ES-like cells from these embryos. However, ES-like cells from the D7 blastocysts grew slowly and expressed alkaline phosphatase. The cells from the D9 blastocysts grew rapidly but did not express alkaline phosphatase. ES-like cells were not isolated from the D5 blastocysts. These results show that the cells from the D7 embryos are pluripotent but grow slowly. The cells from the D9 embryos grow rapidly but start to lose pluripotency.
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A fine balance between CCNL1 and TIMP1 contributes to the development of breast cancer cells.
Biochem. Biophys. Res. Commun.
PUBLISHED: 04-25-2011
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Cyclin L1 (CCNL1) and tissue inhibitor of matrix metalloproteinase-1 (TIMP1) are candidate genes involved in several types of cancer. However, the expression of CCNL1 and the relationship between CCNL1 and TIMP1 in breast cancer cells is unknown. Using patients breast cancer tissues, the expression of CCNL1 and TIMP1 was measured by cDNA microarray and further confirmed by real-time RT-PCR and western blotting. Overexpression or repression of CCNL1 and TIMP1, individually or together, was performed in breast cancer MDA-MB-231 cells by transient transformation methods to investigate their role in breast cancer cell growth. Simultaneously, mRNA and protein expression levels of CCNL1 and TIMP1 were also measured. CCNL1 and TIMP1 expression was significantly elevated in breast cancer tissues compared with that in peri-breast cancer tissues of patients by cDNA microarray and these results were further confirmed by real-time RT-PCR and western blotting. Interestingly, in vitro experiments showed a stimulatory effect of TIMP1 and an inhibitory effect of CCNL1 on growth of MDA-MB-231 cells. Co-expression or co-repression of these two genes did not affect cell growth. Overexpression of CCNL1 and TIMP1 individually induced overexpression of each other. These data demonstrate that there is a fine balance between CCNL1 and TIMP1, which may contribute to breast cancer development.
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In vitro inhibition of CSFV replication by multiple siRNA expression.
Antiviral Res.
PUBLISHED: 03-11-2011
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Classical swine fever (CSF) is a highly contagious viral disease of pigs which causes major economic losses worldwide. No specific drug is currently available for the effective treatment of CSFV infection; however, RNA interference (RNAi) has been applied successfully to inhibit the replication of human and other animal viruses. In this study, three effective siRNAs targeting NS3 of CSFV were selected. siNS3-2 targeting NS3 gene was chosen for further experimentation, while siN1 and siN2 targeting N(pro) gene, and siNS5B targeting NS5B gene describe previously. Single, double and quadruple anti-CSFV siRNA expression plasmids, with loxp sites at each end of the selectable marker genes, were constructed and analyzed using the same promoters or four different promoters, targeting N(pro), NS3 and NS5B genes of CSFV. Results indicate that single or multiple siRNA expression plasmids can efficiently inhibit CSFV replication and that inhibition was markedly stronger when multiple siRNAs were expressed targeting different genes of CSFV. Since RNAi applied to anti-CSFV research, this study provides anti-CSFV methods by single and multiple siRNA expression which can target most viral isolates of different subtypes and prevent viral escape. It also provides a basis for development of CSFV-resistant transgenic pigs.
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Overexpression of Shadoo protein in transgenic mice does not impact the pathogenesis of scrapie.
Neurosci. Lett.
PUBLISHED: 02-22-2011
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Shadoo is a glycoprotein expressed in the adult brain that is an interacting protein of prion protein; however, its function remains to be determined. To elucidate its role in prion pathogenesis, we generated transgenic mice overexpressing wild-type (wt) Shadoo driven by the murine PrP promoter. Expression of the murine Sprn transgene significantly increased brain Shadoo protein levels in all three mouse lines generated. Following infection with mouse-adapted scrapie strain 22L, all transgenic mice tested exhibited characteristics of scrapie disease. Importantly, there was no correlation between the expression level or incubation time of Shadoo with disease phenotype. We therefore conclude that Shadoo has little or no influence on the outcome of transmissible spongiform encephalopathy (TSE) disease in transgenic mice.
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Construction of a recombinant human FGF1 expression vector for mammary gland-specific expression in human breast cancer cells.
Mol. Cell. Biochem.
PUBLISHED: 01-15-2011
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Human Fibroblast growth factor 1 (FGF1) has been recognized as a valuable protein drug for the treatment of many diseases because of its multiple functions in regulating a variety of biological processes involved in embryonic development, cell growth and differentiation, morphogenesis, tissue repair, and others. The aim of this study was to develop an FGF1 mammary gland-specific expression vector to produce FGF1 on a large scale from transgenic cows to meet the demand for FGF1 in medical use. In this study, we generated an FGF1 mammary gland-specific expression vector and validated its function in human MCF-7 cells. This vector was shown to successfully express functional FGF1, thus potentially enabling the generation of transgenic cows to be used as mammary gland bioreactors.
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Human MxA protein inhibits the replication of classical swine fever virus.
Virus Res.
PUBLISHED: 01-11-2011
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Classical swine fever virus (CSFV) has a spherical enveloped particle with a single stranded RNA genome, the virus belonging to a pestivirus of the family Flaviviridae is the causative agent of an acute contagious disease classical swine fever (CSF). The interferon-induced MxA protein has been widely shown to inhibit the life cycle of certain RNA viruses as members of the Bunyaviridae family and others. Interestingly, it has been reported that expression of MxA in infected cells was blocked by CSFV and whether MxA has an inhibitory effect against CSFV remains unknown to date until present. Here, we report that CSFV replicated poorly in cells stably transfected with human MxA. The proliferation of progeny virus in both PK-15 cell lines and swine fetal fibroblasts (PEF) continuously expressing MxA was shown significantly inhibited as measured by virus titration, indirect immune fluorescence assay and real-time PCR.
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Nitroalkenes induce rat aortic smooth muscle cell apoptosis via activation of caspase-dependent pathways.
Biochem. Biophys. Res. Commun.
PUBLISHED: 05-12-2010
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Nitroalkene derivatives of nitro-linoleic acid (LNO(2)) and nitro-oleic acid (OA-NO(2)) are nitrated unsaturated fatty acids that can be detected in healthy human plasma, red blood cells and urine. It has been shown that nitroalkenes have potent anti-inflammatory properties in multiple disease models. In the present study, we are the first to investigate the apoptotic effects of nitroalkenes in rat aortic smooth muscle cells (RASMCs). We observed that nitroalkenes induce RASMCs apoptosis in a dose-dependent manner. In addition, nitroalkenes stimulate extrinsic caspase-8 and intrinsic caspase-9 activity to trigger the caspase-3 apoptotic signaling cascade, resulting in RASMCs death. Furthermore, the pro-apoptotic protein, Bad was upregulated and antiapoptotic protein, Bcl-xl was downregulated during nitroalkene-induced apoptosis. These results demonstrate that nitroalkenes can induce RASMCs apoptosis via stimulation of caspase activity and the regulation of apoptotic protein expression levels.
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Establishment of a transgenic pig fetal fibroblast reporter cell line for monitoring Cre recombinase activity.
DNA Cell Biol.
PUBLISHED: 04-08-2009
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The pig is considered to be the most suitable nonhuman source of organs for xenotransplantation and is widely used as a model of human disease. The Cre-LoxP system provides a powerful means of cell- or tissue-specific deletion of a targeted gene in cells or tissues of interest. Pigs expressing Cre recombinase have a profound impact on the study of gene function and the generation of animal models of human diseases. To monitor Cre recombinase expression in vivo, it is important to create reporter strains. As a first step in the production of such transgenic pigs, we generated porcine fetal fibroblast cell lines conditionally expressing the gene for enhanced green fluorescent protein (EGFP). The EGFP gene is expressed only after Cre-mediated excision of LoxP-flanked stop sequences. These fetal fibroblast cell lines will be of great value for constructing reporter transgenic pigs.
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Production of a reporter transgenic pig for monitoring Cre recombinase activity.
Biochem. Biophys. Res. Commun.
PUBLISHED: 02-19-2009
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The pig is thought to be the most suitable non-human source of organs for xenotransplantation and is widely used as a model of human disease. Using pigs as disease models requires the design of conditional Cre recombinase-loxP gene modifications, which, in turn, requires a Cre-expressing pig with defined patterns of expression controlled by the use of a tissue-specific promoter. In order to monitor Cre recombinant expression in vivo, it is important to create a reporter strain. We have generated reporter a pig that is based on a single vector that drives the ubiquitous expression of the enhanced green fluorescent protein (EGFP). The EGFP gene is expressed only after Cre-mediated excision of loxP-flanked stop sequences. These reporter transgenic pigs will be of great value for monitoring Cre recombinase activity in vivo.
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Comparative analysis of different methods to enhance porcine circovirus 2 replication.
J. Virol. Methods
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Porcine circovirus 2 (PCV2) is an extremely slow-growing virus, and PCV2 infection and replication in cell culture yield very low viral titers. The effects of different methods of PCV2 cultivation in vitro were compared with the purpose of increasing viral yield. The results showed that treatment with IL-2, ConA, and D-glucosamine increased PCV2 yield more effectively than other treatments. Additionally, treatment with IL-2, ConA, D-glucosamine and M?CD consistently increased PCV2 infection in PK-15 cells during consecutive viral passages. A combinatorial treatment with ConA, M?CD and D-glucosamine increased PCV2 yield significantly in PK-15 cells, to 1.81×10(10) genome copy numbers per mL of cell lysate at 72 hpi, and the viral titer (-lgTCID50/100 ?L) was 8.6. The results of this study may be helpful for the investigation of PCV2 replication and the production of a PCV2 vaccine.
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Complete genome sequence of porcine circovirus 2b strain CC1.
J. Virol.
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A porcine circovirus 2 (PCV2) strain, designated CC1, was isolated and purified from tissue samples from pigs with wasting syndromes in China. We report the complete genome sequence of PCV2b strain CC1 with a deletion of C at position 1053 resulting in elongation of open reading frame 2 (ORF2) and formation of ORF5. There were 11 ORFs in the genome.
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NF-?B-dependent microRNA-125b up-regulation promotes cell survival by targeting p38? upon ultraviolet radiation.
J. Biol. Chem.
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UV-induced stress response involves expression change of a myriad of genes, which play critical roles in modulating cell cycle arrest, DNA repair, and cell survival. Alteration of microRNAs has been found in cells exposed to UV, yet their function in UV stress response remains elusive. Here, we show that UV radiation induces up-regulation of miR-125b, which negatively regulates p38? expression through targeting its 3-UTR. Increase of miR-125b depends on UV-induced NF-?B activation, which enhances miR-125b gene transcription upon UV radiation. The DNA damage-responsive kinase ATM (ataxia telangiectasia mutated) is indispensable for UV-induced NF-?B activation, which may regulate p38? activation and IKK?-dependent I?B? degradation in response to UV. Consequently, repression of p38? by miR-125b prohibits prolonged hyperactivation of p38? by UV radiation, which is required for protecting cells from UV-induced apoptosis. Altogether, our data support a critical role of NF-?B-dependent up-regulation of miR-125b, which forms a negative feedback loop to repress p38? activation and promote cell survival upon UV radiation.
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Crosstalk between JNK and NF-?B in the KDO2-mediated production of TNF? in HAPI cells.
Cell. Mol. Neurobiol.
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Both nuclear factor kappa B (NF-?B) and mitogen-activated protein kinases mediate production of proinflammatory cytokines in many types of cells. c-Jun N-terminal kinases (JNK) is a key regulator of many cellular events including cell inflammation and/or programmed cell death (apoptosis). In addition to mediating immune and inflammatory responses, NF-?B transcription factors control cell survival. It is reported that activation of NF-?B antagonizes apoptosis or programmed cell death by numerous triggers. It has been reported that NF-?B activation results in rapid inactivation of JNK in tumor necrosis factor alpha (TNF?)-treated murine embryonic fibroblasts. It is not clear about the relationship of JNK and NF-?B in the microglial cells induced by TLR4 activity. In the present study, we investigated the relationship of JNK and NF-?B in the highly aggressively proliferating immortalized microglial cell line treated with KDO2 (a TLR4 agonist). KDO2 treatment significantly induced the phosphorylation of JNK and NF-?B, and released TNF?. Knockdown of TLR4 with TLR4 siRNA significantly reduced phosphorylation of JNK (pJNK), phosphorylation of NF-?B, and release of TNF?. Inhibition of JNK reduced the release of TNF?, but not phosphorylation of NF-?B. Unexpectedly, inhibition of NF-?B enhanced pJNK and the release of TNF?. These results showed that TNF? induced by KDO2 was JNK-dependent, and that NF-?B negatively modulated both pJNK and TNF? in the cultured microglial cell line. The current study may provide a new insight in the modulation of TNF? in the microglial cell line.
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Site-directed mutagenesis and over expression of aroG gene of Escherichia coli K-12.
Int. J. Biol. Macromol.
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3-Deoxy-D-arabino-heptulonate-7-phosphate (DAHP) synthetase is one of the key enzymes, which catalyzes the first step in the aromatic amino acid biosynthetic pathway and yields the three amino acids tyrosine, tryptophan, and phenylalanine. In Escherichia coli (E. coli), three differently regulated DAHP synthases carry out the first regulated step in the aromatic amino acid biosynthetic pathway. The three DAHP synthases encoded by the genes aroG, aroF and aroH are inhibited by phenylalanine, tyrosine and tryptophan, respectively. In this work, the aroG gene was cloned and mutated by site-directed mutagenesis using splicing overlap extension PCR (SOE-PCR) technique. The feedback-resistant DAHP synthase encoded by aroG was achieved by replacing the residue Leu175 of aroG with Asp as to increase net carbon flow down the common pathway. SDS-PAGE which was used to access the protein expression level of aroGM showed the strain harbored mutated aroGM gene achieve over-expression compared to strain contain empty plasmid pET-28b (+).
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The construction and expression of lysine-rich gene in the mammary gland of transgenic mice.
DNA Cell Biol.
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Lysine is the limiting amino acid in cereal grains, which represent a major source of human food and animal feed worldwide, and is considered the most important of the essential amino acids. In this study, ?-casein, ?S2-casein, and lactotransferrin cDNA clone fragments encoding lysine-rich peptides were fused together to generate a lysine-rich (LR) gene and the mammary gland-specific expression vector pBC1-LR-NEO(r) was constructed. Transgenic mice were generated by pronuclear microinjection of the linearized expression vectors harboring the LR transgene. The transgenic mice and their offspring were examined using multiplex polymerase chain reaction (PCR), Southern blotting, reverse transcriptase-PCR, in situ hybridization, and Western blotting techniques. Our results showed that the LR gene was successfully integrated into the mouse genome and was transmitted stably. The specific LR gene expression was restricted to the mammary gland, active alveoli of the transgenic female mice during lactation. The lysine level of the two transgenic lines was significantly higher than that of nontransgenic controls (p<0.05). In addition, the growth performance of transgenic pups was enhanced by directly feeding them the LR protein-enriched transgenic milk. Our results demonstrated that lysine-rich gene was successfully constructed and expressed in mammary gland of transgenic mice. This study will provide a better understanding of how mammary gland expression systems that increase the lysine content of milk can be applied to other mammals, such as cows.
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TNF? and IL-1? are mediated by both TLR4 and Nod1 pathways in the cultured HAPI cells stimulated by LPS.
Biochem. Biophys. Res. Commun.
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A growing body of evidence recently suggests that glial cell activation plays an important role in several neurodegenerative diseases and neuropathic pain. Microglia in the central nervous system express toll-like receptor 4 (TLR4) that is traditionally accepted as the primary receptor of lipopolysaccharide (LPS). LPS activates TLR4 signaling pathways to induce the production of proinflammatory molecules. In the present studies, we verified the LPS signaling pathways using cultured highly aggressively proliferating immortalized (HAPI) microglial cells. We found that HAPI cells treated with LPS upregulated the expression of TLR4, phospho-JNK (pJNK) and phospho-NF-?B (pNF-?B), TNF? and IL-1?. Silencing TLR4 with siRNA reduced the expression of pJNK, TNF? and IL-1?, but not pNF-?B in the cells. Inhibition of JNK with SP600125 (a JNK inhibitor) decreased the expression of TNF? and IL-1?. Unexpectedly, we found that inhibition of Nod1 with ML130 significantly reduced the expression of pNF-?B. Inhibition of NF-?B also reduced the expression of TNF? and IL-1?. Nod1 ligand, DAP induced the upregulation of pNF-?B which was blocked by Nod1 inhibitor. These data indicate that LPS-induced pJNK is TLR4-dependent, and that pNF-?B is Nod1-dependent in HAPI cells treated with LPS. Either TLR4-JNK or Nod1-NF-?B pathways is involved in the expression of TNF? and IL-1?.
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Direct conversion of porcine embryonic fibroblasts into adipocytes by chemical molecules.
Cell Reprogram
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Direct reprogramming of terminally differentiated cells to specify different cell types may allow somatic cells to be reprogrammed to an alternative, differentiated fate without intervening stem or progenitor cells. Recent studies have shown that the conversion of fibroblasts to other cell lines can be accomplished by the introduction of master regulator transcription factors. These findings have raised the question as to whether chemical molecules could replace transcription factor cocktails to directly alter defined somatic cell fate. Here, we demonstrate the generation of adipocytes directly from porcine embryonic fibroblasts (PEFs) using defined chemical molecules. Treatment with SB431542 and Thiazovivin, which are transforming growth factor-beta (TGF-?) and ROCK signaling pathway inhibitors, respectively, allowed PEFs to directly convert to fat-laden adipocytes. These induced adipocytes expressed multiple fat marker genes. We believe that these findings demonstrate that committed adipocytes can be directly reprogrammed from differentiated somatic cells using defined chemical molecules. The generation of adipocytes from nonadipogenic lineages has important implications for studies of adipogenesis, obesity modeling, and regenerative medicine. Additionally, these findings may enlighten a new method that direct reprogramming committed cell lines to other somatic cells using defined chemical molecules.
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