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Publications (5)15.18 Total impact

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    ABSTRACT: The biohazards caused by the viral delivery of pancreatic transcription factors, including neurogenic differentiation 1 (Neurod1) and Betacellulin (Btc), to the murine liver limit application of this procedure in reversing diabetes. We aimed to evaluate the feasibility of hydrodynamics-based transfection (HBT) with Neurod1 and Btc in improving hyperglycemia. Murine hepatocellular carcinoma (Hepa1-6) cells were transfected with the combination of Neurod1-expressing plasmid, pcDNA3.1/V5-His A (pcDNA)-Neurod1, and Btc-expressing plasmid, pcDNA3.1/V5-His A (pcDNA)-Btc. Hepatic delivery of a combination of pcDNA-Neurod1 and pcDNA-Btc (experimental group) or pcDNA (control group) to mice with streptozocin-induced diabetes was achieved by HBT. The sequential serum glucose and alanine aminotransferase (ALT) levels were assessed. On day 3 after transfection, the transfection efficiencies of pcDNA-Btc and pcDNA-Neurod1 in the Hepa1-6 cells were 20% and 8%, respectively; respective values in the mouse livers were 30% and 10%. At 1 week after HBT, aside from hepatic expression of insulin, the experimental mice had a significantly lower sugar level (8-14 days after HBT, P values ranged from 0.034 to <0.001) than the control mice; the difference remained for 1 week but diminished afterward. The ALT levels and the body weight change were not different between the two groups. No mortality was noted in both groups. The hypoglycemic effect of Neurod1 and Btc delivered by HBT was transient and associated with negligible complications. In studies on the short-term hypoglycemic effects of Neurod1 and Btc in vivo, HBT is a potential alternative to viral delivery of Neurod1 and Btc to the murine liver.
    Diabetes Technology &amp Therapeutics 03/2011; 13(5):519-25. · 2.21 Impact Factor
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    ABSTRACT: The biohazards caused by the viral delivery of pancreatic duodenal homeobox gene 1 (Pdx1) to the murine liver limits its application. We aimed to evaluate the feasibility of hydrodynamics-based transfection (HBT) with Pdx1 in improving hyperglycemia. Murine hepatocellular carcinoma (Hepa1-6) cells were transfected with the Pdx1-expressing plasmid, pcDNA3.1/V5-His A (pcDNA)-Pdx1. Hepatic delivery of pcDNA-Pdx1 or pcDNA in streptozocin- induced diabetic mice was achieved by HBT. The sequential serum glucose and alanine aminotransferase (ALT) levels were assessed. On the 3(rd) day after transfection, the transfection efficiency in the Hepa1-6 cells and the mice livers was 5% and 0.35 %, respectively. At 1 wk after HBT, asides from hepatic expression of insulin, the diabetic mice transfected with pcDNA-Pdx1 had a significantly lower sugar (211 +/- 61.6 vs. 413 +/- 62 mg/dL; p = 0.002) level than those transfected with pcDNA; however, the difference diminished afterward. No significant difference in the ALT levels was observed between the 2 groups. No mortality was noted in the mice transfected with pcDNA-Pdx1. The hypoglycemic effect of Pdx1 delivered by HBT was transient and associated with negligible complications. In studies on the short-term biological effects of Pdx1 in vivo, HBT is a potential alternative to viral delivery of Pdx1 to the murine liver.
    Endocrine Journal 07/2009; 56(6):783-90. · 2.23 Impact Factor
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    ABSTRACT: Although in vivo nonviral gene delivery to the liver is critical for hepatic gene therapy, there are a number of technical obstacles. Enhanced green fluorescent protein (EGFP)-encoding DNA was coated onto gold particles (gold-DNA), dissolved in phosphate-buffered saline (pure DNA), and prepared as a polymer adjuvant (jetPEI)-galactosidase solution (polymer-DNA). Murine liver transfection was attempted by nonviral approaches, which included hydrodynamics-based transfection (HBT) of pure DNA, transport and transhepatic injection of polymer-DNA, and gene gun bombardment with pure DNA, gold-DNA, and polymer-DNA. Only HBT and gene gun bombardment yielded significant numbers of EGFP(+) hepatocytes. With the exception of the edge of the liver, HBT had a whole-liver transfection rate of 20% under optimized conditions. HBT resulted in marked hepatic infarctions, most prominently at the edge of the liver. For gene gun bombardment, the transfection rate was pressure dependent and limited to 15% for gold-DNA. Triple or quadruple bombardment at 30 psi resulted in a transfection rate comparable to that of a single bombardment at higher pressure, but was associated with minimal scattered hepatic necrosis. The EGFP(+) hepatocytes were located mainly in the superficial layers. We conclude that both HBT and gene gun bombardment yielded efficient murine hepatocyte transfection in vivo. Severe hepatic infarction impedes foreign gene expression in the superficial hepatocytes after HBT. Repeated bombardment with gold-DNA, using an accelerated particle gene gun at 30 psi, is a potential alternative to HBT for delivering genes to superficial hepatocytes in vivo, although gold-related hepatic necrosis is a persistent problem.
    Human Gene Therapy 05/2008; 19(4):391-5. · 4.02 Impact Factor
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    ABSTRACT: Because the gene expression patterns of nonobese hepatic steatosis in affected patients remain unclear, we sought to explore these patterns using an animal model of nonobese hepatic steatosis. We developed mice that conditionally express the hepatitis C virus (HCV) core protein regulated by the tetracycline transactivator (tTA). Microarray analyses and reverse-transcription polymerase chain reaction were performed using liver samples of both the double transgenic mice (DTM), which express both the HCV core and tTA, and single transgenic mice (STM), which express tTA alone, at 2 months of age. Functional categories of genes with altered expression were classified using gene ontology programs. Serum glucose, lipid levels, and systemic blood pressure were also measured. Approximately 20-30% of hepatocytes from the DTM were steatotic. No significant differences were observed in the serum glucose, lipid content, or blood pressure levels between the DTM and STM. Gene expression analyses revealed Sterol-regulatory element-binding protein (SREBP) pathway activation and dysregulation of the following genes involved in lipid metabolism: 3-hydroxy-3-methylglutaryl-coenzyme A synthase 1, Apolipoprotein AII, Apolipoprotein CI, acyl-CoA thioesterase I, and fatty acid binding protein 1; in mitochondrial function: solute carrier family 25 member 25 and cytochrome c oxidase subunit II; in immune reaction: complement component 3, lymphocyte antigen 6 complex, locus A, lymphocyte antigen 6 complex, locus C, lymphocyte antigen 6 complex, locus D, and lymphocyte antigen 6 complex, locus E. Some genes of lipid metabolism, mitochondrial function, and immune reaction and the SREBP pathway are involved in HCV core-related, nonobese, modest hepatic steatosis.
    BMC Genomics 02/2008; 9:109. · 4.40 Impact Factor
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    ABSTRACT: In infection with hepatitis C virus (HCV), spontaneous clearance of the virus occurs in 30-40% of cases. By contrast, in chronic infection, this is rare. The basis for viral clearance in acute disease is unknown. Whereas cellular immune responses have been studied in detail, few data exist on the role of viral structural proteins, such as the core protein. The purpose of this study was to investigate the effects of core produced de novo within adult mouse hepatocytes by using a new transgenic mouse line in which expression of HCV core is regulated by tetracycline (tet-off). In this work, transgenic mice with conditional HCV core were created, to study the acute expression of HCV core protein in the context of the mature liver. The subcellular distribution of the core, hepatocellular oxidative stress and apoptosis were monitored. Core protein is readily detectable and strongly associated with cytoplasmic lipid vesicles, endoplasmic reticulum and mitochondria. Mitochondrial oxidative stress was evidenced by a reduction in thioredoxin-2 (trx2). Concurrently, caspase-3 activity and TUNEL increased and, over time, the level of core protein in the liver declined. Mice that are conditionally transgenic for HCV core protein, which is readily detected and morphologically associated with steatosis in individual hepatocytes, were developed. Acute expression of core protein causes mitochondrial stress, as demonstrated by a reduction in trx2 and in the apoptosis of core-positive hepatocytes. We speculate that these events could be involved in the clearance of virus during acute hepatitis C, by both reducing the burden of virus in the liver and effectively priming the immune response.
    Scandinavian Journal of Gastroenterology 02/2008; 43(6):747-55. · 2.33 Impact Factor