- Regulation of mFABP (fatty acid binding protein) Expression by PPAR in Cultured Human Skeletal Muscle Cell.
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Hyeosn Jeong Jeon, Won Shik Shinn, Jeong Mi Kim, Hye Kyung Hong, Kyong Soo Park, Seong Yeon Kim, Hong Kyu Lee
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Korean Diabetes J. 2000;24(4):413-420. Published online January 1, 2001
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Abstract
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- BACKGROUND
Fatty acid binding protein (FABP), putative mammalian fatty acid transporter, plays a role in fatty acid transport, the modulation of cellular signal transduction pathways and the protection against detergent like effects of fatty acids. FABP found in liver, adipose tissue, heart, skeletal muscle and FABP in skeletal muscle accounts for 2% of total protein mass. FABP expression has shown to be up-regulated by PPAR in liver and adipocyte. Adipocyte and liver FABP genes have a functional PPRE (PPAR responsive element) in their promoter region. This evidence led us to investigate for a possible the regulation of mFABP expression by PPAR in cultured human skeletal muscle cell. METHODS: Myoblast were cultured in SkGM for 4weeks and were differentiated into myocyte in MEM for 4days. The myocytes were treated with PPAR ligand (troglitazone: 5 g/mL) or transduction with adenovirus-PPAR 1 (Ad-PPAR 1). mFABP expression was identified by northern blot. RESULTS: mFABP expression was up-regulated by 4.0+/-1.2 fold in the PPAR ligand (p<0.05). There was increased in mFABP expression with transduction with adenovirus-PPAR 1 while there was no change in mFABP expression which transducted with adenovirus - -galactosidase. CONCLUSION: These results demonstrates that mFABP expression is up-regulated by both PPAR ligand and by PPAR 1 over expression in cultured human skeletal muscle cells.
- Metabolic Phenotype of Glycogen Synthase Gene Inhibition in Human Skeletal Muscle Cells.
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Jae Joon Koh, Kyong Soo Park, Jeong Mi Kim, Seong Yeon Kim, Hong Kyu Lee, Theodore P Ciaraldi, Robert R Henry
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Korean Diabetes J. 2000;24(3):331-339. Published online January 1, 2001
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Abstract
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- BACKGROUND
Glycogen synthase (GS) is the rate-limiting enzyme controlling non-oxidative glucose disposal in skeletal muscle. Reduction in GS activity and impaired insulin responsiveness are characteristic features of skeletal muscle in type 2 diabetes that contribute to glucose intolerance. These properties also exist in human skeletal muscle cell cultures from type 2 diabetic subjects. The aim of study is to determine the effect of an isolated reduction in GS on glucose metabolism and if this change can generate a diabetes-like state. METHODS: Cultured skeletal muscle cells from non-diabetic subjects were treated with antisense oligodeoxynucleotides (ODN) to GS to interfere with expression of the gene for 6 days. GS activity, protein expression, glycogen synthesis and cellular glycogen content were measured. RESULTS: Treatment with antisense ODN reduced GS protein expression by 70% compared to control (scrambled) ODN (p<0.01). Both total GS activity and that measured at 0.1 mM G-6-P were reduced by antisense ODN treatment. Insulin responsiveness of GS was also halved. Basal GS FV0.1 was decreased in both antisense ODN and control ODN treated cells and antisense treated cells did not show increase in GS FV0.1 in response to insulin stimulation. Glucose incorporation into glycogen under basal conditions was unaltered after antisense ODN treatment, though no further stimulation in response to insulin was observed. Yet both cellular glycogen content and glycogen synthesis were lower in antisense ODN treated cells compared to control ODN treated cells. CONCLUSIONS: Reduction in GS expression in human skeletal muscle cell impair GS activity and insulin responsiveness but does not replicate the abnormalities of glycogen synthesis found in cultured diabetic skeletal muscle cells.
- Expression of Gal alpha1,3 Gal Antigen and Galactosyl Transferase mRNA in Porcine Neonatal Pancreatic Tissue.
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Kyong Soo Park, Yoon Young Kim, Jeong Mi Kim, Yu Bae Ahn, Kun Ho Yoon, Bong Yun Cha, Ho Young Son, Hong Kyu Lee
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Korean Diabetes J. 2000;24(3):323-330. Published online January 1, 2001
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Abstract
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- BACKGROUND
Neonatal porcine pancreatic tissue may be a potential source of islet transplantation in patients with type 1 diabetes. Gal 1,3 Gal antigen (Gal epitope) is a xenoantigen which is responsible for hyperacute xenograft rejection. The aim of this study is to evaluate the expression of Gal epitope and galactosyl transferase mRNA in porcine neonatal pancreatic tissue. METHOD: Porcine neonatal pancreatic cell clusters (NPCCs) were isolated using collagenase and incubated in various culture condition. They were stained with Gal specific lectin for the detection of Gal epitope. Expression of 1,3 galactosyl transferase mRNA was assessed by semiquantitative RT-PCR. RESULTS: Gal epitope was expressed in both neonatal porcine pancreas and cell clusters. Most of Gal epitope expressed cells were endothelial cells and ductal epithelial cells. A small number of cells stained positive for insulin were also positive for Gal epitope. In some area of monolayer culture of porcine neonatal islet cluster, scattered insulin positive cells coexpressed the Gal epitope. The expression of 1,3 galactosyl transferase mRNA were lower in islet than other tissues. Culture using extracelluar matrix or 3D gel increased the expression of 1,3 galactosyl transferase mRNA levels. CONCLUSION: Gal epitope was expressed in ductal epithelial cells and some of beta cells of porcine neonatal pancreatic tissue. Expression of Gal epitope in porcine neonatal pancreatic cell cluster may be a problem that needs to be solved before porcine NPCCs can be used in human.
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