• Journal of Microbiology and Biotechnology
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• v.33 no.12
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• pp.1563-1575
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• 2023

Acyl-coenzyme A (CoA):diacylglycerol acyltransferase 2 (DGAT2) catalyzes the last stage of triacylglycerol (TAG) synthesis, a process that forms ester bonds with diacylglycerols (DAG) and fatty acyl-CoA substrates. The enzymatic role of Dgat2 has been studied in various biological species. Still, the full description of how Dgat2 channels fatty acids in skeletal myocytes and the consequence thereof in glucose uptake have yet to be well established. Therefore, this study explored the mediating role of Dgat2 in glucose uptake and fatty acid partitioning under short interfering ribonucleic acid (siRNA)-mediated Dgat2 knockdown conditions. Cells transfected with Dgat2 siRNA downregulated glucose transporter type 4 (Glut4) messenger RNA (mRNA) expression and decreased the cellular uptake of [1-¹⁴C]-labeled 2-deoxyglucose up to 24.3% (p < 0.05). Suppression of Dgat2 deteriorated insulin-induced Akt phosphorylation. Dgat2 siRNA reduced [1-¹⁴C]-labeled oleic acid incorporation into TAG, but increased the level of [1-¹⁴C]-labeled free fatty acids at 3 h after initial fatty acid loading. In an experiment of chasing radioisotope-labeled fatty acids, Dgat2 suppression augmented the level of cellular free fatty acids. It decreased the level of re-esterification of free fatty acids to TAG by 67.6% during the chase period, and the remaining pulses of phospholipids and cholesteryl esters were decreased by 34.5% and 61%, respectively. Incorporating labeled fatty acids into beta-oxidation products increased in Dgat2 siRNA transfected cells without gene expression involving fatty acid oxidation. These results indicate that Dgat2 has regulatory function in glucose uptake, possibly through the reaction of TAG with endogenously released or recycled fatty acids.

• Journal of Animal Science and Technology
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• v.51 no.6
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• pp.493-502
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• 2009

Glucose is a major source of metabolic fuel and lipid and protein syntheses. Transport of glucose into the cell is regulated by an action of glucose transport.associated transporters, especially solute carriers 2A (Slc2a, protein symbol GLUT). The present study was focused on examination of mRNA expression of various Slc2a isoforms in the epididymis during postnatal development. Total RNAs isolated from different epididymal segments (caput, corpus, and caudal epididymis) were utilized for real-time polymerase chain reaction analyses. Results showed that Slc2a 1, 3, 4, 5, and 8 were expressed in the entire epididymal regions. In addition, the abundance of these Slc2a isoforms' transcripts was different within each epididymal regions. Moreover, the present study showed differential expression of these Slc2a isoforms among different epididymal segments according to postnatal ages. The current study suggests that glucose transport in the epididymis via various Slc2a isoforms would be necessary for maintenance of the epididymal functions.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.12
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• pp.1674-1680
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• 2011

This study was conducted to examine the effects of glucose, chromium picolinate (CrP), and vitamin C (Vit C) on lipid metabolism in Korean native steers fitted with indwelling catheters. A total of 12 Korean native steers were randomly allocated to the following treatments: 1) normal control diet, 2) same as 1) +250 g of glucose by intravenous (IV) infusion, 3) same as 2)+13.5 g CrP administered orally, and 4) same as 3)+2.52 g Vit C by IV infusion. Glucose, Vit C, and CrP treatments were administered for five days. At days 1 and 3, serum insulin was higher in treated animals than in those fed the control diet (p<0.05). Serum non-esterified fatty acid (NEFA) concentration in the steers on treatment 2), control+13.5 g CrP, was lower than those on other treatments at 90 min post-infusion on days 1 and 3 (p<0.05). The expression of peroxisome proliferator-activated receptor-${\gamma}$ (PPAR${\gamma}$)2, stearoyl-CoA desaturase-1 (SCD), fatty acid synthase (FAS), and glucose transporter type 4 (Glut 4) in the longissimus muscle of steers on treatment 2 was higher than those on other treatments. In conclusion, the results suggest that CrP is associated with the regulation of gene expression involved in adipogenesis.

• Molecules and Cells
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• v.44 no.10
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• pp.710-722
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• 2021

Hypoxia, or low oxygen tension, is a hallmark of the tumor microenvironment. The hypoxia-inducible factor-1α (HIF-1α) subunit plays a critical role in the adaptive cellular response of hypoxic tumor cells to low oxygen tension by activating gene-expression programs that control cancer cell metabolism, angiogenesis, and therapy resistance. Phosphorylation is involved in the stabilization and regulation of HIF-1α transcriptional activity. HIF-1α is activated by several factors, including the mitogen-activated protein kinase (MAPK) superfamily. MAPK phosphatase 3 (MKP-3) is a cytoplasmic dual-specificity phosphatase specific for extracellular signal-regulated kinase 1/2 (Erk1/2). Recent evidence indicates that hypoxia increases the endogenous levels of both MKP-3 mRNA and protein. However, its role in the response of cells to hypoxia is poorly understood. Herein, we demonstrated that small-interfering RNA (siRNA)-mediated knockdown of MKP-3 enhanced HIF-1α (not HIF-2α) levels. Conversely, MKP-3 overexpression suppressed HIF-1α (not HIF-2α) levels, as well as the expression levels of hypoxia-responsive genes (LDHA, CA9, GLUT-1, and VEGF), in hypoxic colon cancer cells. These findings indicated that MKP-3, induced by HIF-1α in hypoxia, negatively regulates HIF-1α protein levels and hypoxia-responsive genes. However, we also found that long-term hypoxia (>12 h) induced proteasomal degradation of MKP-3 in a lactic acid-dependent manner. Taken together, MKP-3 expression is modulated by the hypoxic conditions prevailing in colon cancer, and plays a role in cellular adaptation to tumor hypoxia and tumor progression. Thus, MKP-3 may serve as a potential therapeutic target for colon cancer treatment.

• Korean Journal of Poultry Science
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• v.42 no.3
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• pp.231-238
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• 2015

The present study aimed to investigate the effects of lycopene on hepatic metabolic- and immune-related gene expression in laying hens. A total of 48 25-week-old White Leghorn hens were randomly allocated into four groups consisting of four replicates of three birds: control (basal diet), T1 (basal diet + 10 mg/kg of tomato powder-containing lycopene), T2 (basal diet + 10 mg/kg of micelles of tomato powder-containing lycopene), and T3 (basal diet + 10 mg/kg of purified lycopene). Chickens were fed ad libitum for 5 weeks, and then total RNA was extracted from the livers for quantitative RT-PCR analysis. Peroxisome proliferator-activated receptor ${\gamma}$ (PPAR${\gamma}$) expression was decreased in the liver of chickens after lycopene supplementation (P<0.05). Micellar lycopene supplementation decreased the expression of PPAR${\gamma}$ target genes including fatty acid binding protein 4 (FABP4) and fatty acids synthase (FASN) in the T2 group (P<0.05). Sterol regulatory element-binding protein 2 (SREBP2) and C/EBP-${\alpha}$ were also downregulated in hens fed with micellar lycopene (P<0.05). Glucose transporter 8 (GLUT-8) was upregulated in the T2 and T3 groups (P<0.05). However, the expression of carnitine palmitoyltransferase 1 (CPT-1) was not changed by lycopene supplementation. Pro-inflammatory cytokines such as tumor necrosis factor ${\alpha}$ (TNF-${\alpha}$) and interleukin 6 (IL-6) were downregulated by lycopene supplementation (P<0.05). These data suggest that the type of lycopene supplementation is critical and that micelles of tomato powder-containing lycopene may play an important role in the modulation of lipid metabolism and immunity in chickens.

• Korean Journal of Poultry Science
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• v.43 no.1
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• pp.47-54
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• 2016

The aim of this study was to investigate the expression patterns of key genes involved in lipid metabolism in response to dietary Coenzyme Q10 (CoQ10) in hens. A total of 36 forty week-old Lohmann Brown were randomly allocated into 3 groups consisting of 4 replicates of 3 birds. Laying hens were subjected to one of following treatments: Control (BD, basal diet), T1 (BD+ CoQ10 100 mg/kg diet) and T2 (BD+ micellar of CoQ10 100 mg/kg diet). Birds were fed ad libitum a basal diet or the basal diet supplemented with CoQ10 for 5 weeks. Total RNA was extracted from the liver for quantitative RT-PCR. The mRNA levels of HMG-CoA reductase(HMGCR) and sterol regulatory element-binding proteins(SREBP)2 were decreased more than 30~50% in the liver of birds fed a basal diet supplemented with CoQ10 (p<0.05). These findings suggest that dietary CoQ10 can reduce cholesterol levels by the suppression of the hepatic HMGCR and SREBP2 genes. The gene expressions of liver X receptor (LXR) and SREBP1 were down regulated due to the addition of CoQ10 to the feed (p<0.05). The homeostasis of cholesterol can be regulated by LXR and SREBP1 in cholesterol-low-conditions. The supplement of CoQ10 caused a decreased expression of lipid metabolism-related genes including $PPAR{\gamma}$, XBP1, FASN, and GLUTs in the liver of birds (p<0.05). These data suggest that CoQ10 might be used as a dietary supplement to reduce cholesterol levels and to regulate lipid homeostasis in laying hens.

• Proceedings of the Korean Society of Developmental Biology Conference
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• 2003.10a
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• pp.60-60
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• 2003

Embryonic stem (ES) cells have property of self-renewal and can differentiate into the cells of all three primary germ layers. Recently, many growth factors, alteration of culture condition and gene modifications have been used to differentiate mouse and human ES cells into specific cell types. This study was performed to evaluate the differentiation protocol for human ES cells to the endodermal lineage cells. Human ES cells (Miz-hESl ) were cultured on STO feeder layer mitotically inactivated with mitemycin C, and embryoid bodies (EBs) were formed by suspension culture. Differentiation protocol of EBs consisted of three steps: stage I, culture of EBs for 6 days with ITSFn medium; stage II, culture of stage I cells for 8 days with N2 medium ; stage III, culture of stage II cells for 22 days with N2 medium. mRNA levels of the endodermal lineage differentiation genes were analyzed by semi- quantitative RT-PCR. The Oct-4 expression, a marker of the pluripotent state, was detected in undifferentiated human ES cells but progressively decreased after EBs formation. Differentiating human ES cells expressed marker genes of endodermal differentiation and pancreatic islet cells. GATA4, a-fetoprotein, Glut-2, and Ngn3 were expressed in all stages. However, albumin and insulin were expressed in only stage III cells. The human ES cells can be differentiated into endodermal lineage cells by multiple step culture system using various supplements. We are developing the more effective protocols for guided differentiation of human ES cells.

• Journal of Physiology & Pathology in Korean Medicine
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• v.30 no.1
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• pp.54-60
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• 2016

Amomum cadamomum Linne (ACL) has long been utilized against the inhibited qi movement related diseases such as dyspepsia, acute gastroenteritis, vomiting and diarrhea in Korean medicine. We speculated that ACL could improve the metabolic disorders such as obesity and type 2 diabetes through removing the phlegm-dampness and promoting the qi movement or stagnation. This study was designed to investigate effects and molecular mechanisms of ACL extract on the improvement of adipocyte dysfunction induced by TNF-α in 3T3-L1 adipocytes. Potential roles of ACL extract in the lipogenesis, inhibition of inflammatory cytokines and insulin resistance, were investigated in this study. Also, we examined the adipose genes and signaling molecules related to insulin resistance and glucose uptake to elucidate its mechanism. Our data demonstrated that TNF-α significantly incresed the release of lipid droplets and the production of MCP-1 and IL-6 from adipocytes. In gene expression, TNF-α reduced the expression of aP2, PPARγ, C/EBPα, GLUT4, and IRS-1 related to lipogenesis and insulin sesitivity, while TNF-α increased the expression of MCP-1 related to inflammation. In addition, TNF-α down-regulated the PPARγ and IRS-1 protein and up-regulated the IRS-1 Ser307 phosphorylation. These alterations induced by TNF-α were prevented by the treatment of ACL extract. Thus, our results indicate that ACL extract can be used to prevent from the TNF-α-induced adipocyte dysfunction through insulin and PPARγ pathways.

• Animal Bioscience
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• v.35 no.1
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• pp.64-74
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• 2022

Objective: This study was conducted to investigate the effects of dietary multi-strain probiotic (MSP) (Bacillus coagulans Unique IS2 + Bacillus subtillis UBBS14 + Saccharomyces boulardii Unique 28) on performance, gut morphology and expression of nutrient transporter related genes in broiler chickens. Methods: A total of 256 (4×8×8) day-old CARIBRO Vishal commercial broiler chicks of uniform body weight were randomly distributed into four treatments with 8 replicates each and having eight chicks in each replicate. Four dietary treatments were T₁ (negative control-basal diet), T₂ (positive control-antibiotic bacitracin methylene disalicylate at 20 mg/kg diet), T₃ (MSP at 10⁷ colony-forming unit [CFU]/g feed), and T₄ (MSP at 10⁸ CFU/g feed). Results: During 3 to 6 weeks and 0 to 6 weeks, the body weight gain increased significantly (p<0.05) in T₃ and T₄ groups. The feed intake significantly (p<0.05) reduced from T₁ to T₃ during 0 to 3 weeks and the feed conversion ratio also significantly (p<0.05) improved in T₃ and T₄ during 0 to 6 weeks. The humoral and cell mediated immune response and the weight of immune organs were also significantly (p<0.05) improved in T₃ and T₄. However, significant (p<0.05) dietary effects were observed on intestinal histo-morphometry of ileum in T₃ followed by T₄ and T₂. At 14 d post hatch, the relative gene expression of glucose transporter (GLUT5), sodium-dependent glucose transporter (SGLT₁) and peptide transporter (PepT₁) showed a significant (p<0.05) up-regulating pattern in T₂, T₃, and T₄. Whereas, at 21 d post hatch, the gene expression of SGLT₁ and PepT₁ was significantly (p<0.05) downregulated in MSP supplemented treatments T₃ and T₄. Conclusion: The supplementation of MSP at 10⁷ CFU/g diet showed significant effects with improved performance, immune response, gut morphology and expression of nutrient transporter genes. Thus, the MSP could be a suitable alternative to antibiotic growth promoters in chicken diets.

• Korean Journal of Pharmacognosy
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• v.38 no.1
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• pp.10-14
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• 2007

Type 2 diabetes mellitus relavant to insulin resistance is a chronic and hard to control. In order to develop an antidiabetic agent from natural products, anti-hyperglycemic effect of herbal formula containing Mori Follium, Euonymi Lignum Suberalatum and Ginseng Radix(MEG) was investigated in db/db mice. Treatment group was administered orally with MEG formula at a dose of 300 mg/kg for 5 weeks, and blood glucose, insulin and lipid levels were determined. MEG treatment group showed a marked decrease in fasting blood glucose level and insulin resistance index(IRI) compared to those in diabetic control. Improvement of insulin resistance(60.6%) was indicative of reducing lipid levels in plasma and triglyceride contents in muscle and adipose tissue. In addition, expressions of an insulin responsive gene, glucose transporter 4(Glut4), in muscle and adipose tissue were upregulated in MEG treatment group. Compared islet morphology between groups, MEG formula prevented the ${\beta}$-cell destruction caused by high blood glucose. Taken together, MEG formula can act as an anti-hyperglycemic agent with insulin sensitizing effect, and thus deserves a clinical trial in the future.