• Journal of Animal Science and Technology
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• v.47 no.6
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• pp.913-918
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• 2005

The development of marbling in cattle is closely associated with an increase in adipocyte size and number within muscle. The adipose precursor cells have the capacity to differentiate into adipocytes within the muscle during the formation of marbling. In this studies, we established the cell culture system for differentiation of intramuscular preadipocyte isolated from the sirloin of Hanwoo aged 12 months. The intramuscular preadipocyte cells exhibited a fibroblastic appearance and differentiated into adipocytes by treating confluent cells with differentiation medium containing insulin, dexamethasone, and troglitazone. When intramuscular preadipocyte cells were differentiated at 18 day, the triglyceride concentration was higher than control cells. Moreover, the thiazolidinedione treatment increased adipogenesis. RT-PCR analysis confirmed the significant expression of PPARγ mRNA during adipocyte differentiation. In conclution, our culture system used in this study allowed intramuscular preadipocyte cells to differentiated into adipocytes and intramuscular preadipocyte cells may be useful in the further study of differentiation mechanism of adipocytes in Hanwoo.

• Journal of Animal Science and Technology
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• v.64 no.6
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• pp.1173-1183
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• 2022

Adipogenesis is a complex process comprising commitment and a differentiation stages. Through research, many different transcriptional factors were found to mediate preadipocyte commitment and differentiation. Lysine has a potential of regulating the commitment and differentiation of preadipocytes. In the present study, intramuscular stromal vascular cells (SVC) isolated from Hanwoo beef cattle were used to elucidate the effects of low lysine level on adipogenesis. SVC were isolated and incubated with various concentrations of lysine (0, 37.5, 75, 150 and 300 µg/mL). No significant difference were observed in the proliferation of SVC after 24 and 48 h of incubation with different concentration of lysine. On preadipocyte determination, reducing the level of lysine significantly increased the expression of preadipocyte commitment gene Zinc finger protein 423 and Preadipocyte factor-1. Upon differentiation, Oil Red O staining revealed that lipid accumulation and triglyceride content significantly increased with the decreasing lysine levels in the media. Expression levels of peroxisome proliferator-activated receptor-γ, CCAAT enhancer binding protein-α, sterol regulatory element binding protein-1c, Fatty Acid Binding Protein 4 and stearoyl CoA desaturase were upregulated by the decreased level of lysine. These data suggest the potential mechanism of action for the improved preadipocyte commitment and adipocyte differentiation in bovine intramuscular SVC upon treatment with low levels of lysine. These findings may be valuable in developing feed rations that promote deposition of intramuscular fat in beef cattle through lysine level modification.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.4
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• pp.446-450
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• 2000

The experiment was conducted to study the effects of water soluble vitamins and retinoic acid on the differentiation of preadipocyte from omental, subcutaneous, intermuscular and intramuscular adipose tissue of Hanwoo. Differentiation was assessed by the change in enzyme activity, glycerol-3 phosphate dehydrogenase in serum free cell culture system. Preadipocytes treated with biotin ($10{\mu}M$) and pantothenic acid ($100{\mu}M$) were significantly (p<0.05) less differentiated than those from the control in all adipose tissue depots except intramuscular tissue. Although there was no significance, vitamin C was shown to stimulate the adipocyte conversion in omental and subcutaneous, but not in intermuscular and intramuscular adipose tissues. Lower values of GPDH activity in intermuscular preadipocyte were interpreted to be caused by relatively higher amounts of protein. In this experiment vitamin C did not stimulate fat deposition in intramuscular adipose tissue but further experiments are needed on the role of vitamin C in preadipocyte differentiation. When treated with different levels of retinoic acids, differentiation of preadipocytes was significantly (p<0.05) reduced from the level of $0.5{\mu}g/ml$ in omental and intermuscular, from $50{\mu}g/ml$ in subcutaneous, and in intramuscular at $500{\mu}g/ml$, thus showing that intramuscular preadipocytes were least responsive to retinoic acid in differentiation. All-trans retinoic acid appeared to inhibit the differentiation in a dose dependent manner, regardless of adipose tissues type.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.5
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• pp.721-726
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• 2009

The molecular mechanism of adipocyte differentiation has been well documented. However, the effect of specific nutrients such as lysine on adipocyte differentiation is poorly understood especially in ruminant animals. Therefore, the aim of the present study was to elucidate the influence of lysine on adipocyte differentiation and adipogenic genes in cultured bovine preadipocytes. The preadipocytes were treated with different concentrations of lysine (40, 160, 320 mg/L) or troglitazone (10 ${\mu}M$) for 2 days and then subsequently cultured in differentiation medium until day 6. Expression levels of $C/EBP{\alpha}$ were significantly higher (p<0.001) in 40 and 160 mg/L lysine-treated cells compared to 320 mg/L treatment. Though there was an increasing trend in $PPAR{\gamma}$ expression levels with the decreasing lysine concentration, the results were not significant. The preadipocyte factor (pref-1), expression significantly (p<0.001) reduced with decreasing lysine concentration. The Oil red O staining results were better in 40 mg/L treated cells compared to 160 and 320 mg/L lysine treated cells. Our overall results indicate that insufficient supply of lysine increases the adipogenic potential in bovine intramuscular preadipocytes.

• BMB Reports
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• v.40 no.5
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• pp.757-764
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• 2007

Marbling of cattle meat is dependent on the coordinated expression of multiple genes. Cattle dramatically increase their intramuscular fat content in the longissimus dorsi muscle between 12 and 27 months of age. We used the annealing control primer (ACP)-differential display RT-PCR method to identify differentially expressed genes (DEGs) that may participate in the development of intramuscular fat between early (12 months old) and late fattening stages (27 months old). Using 20 arbitrary ACP primers, we identified and sequenced 14 DEGs. BLAST searches revealed that expression of the MDH, PI4-K, ferritin, ICER, NID-2, WDNMI, telethonin, filamin, and desmin (DES) genes increased while that of GAPD, COP VII, ACTA1, CamK II, and nebulin decreased during the late fattening stage. The results of functional categorization using the Gene Ontology database for 14 known genes indicated that MDH, GAPD, and COP VII are involved in metabolic pathways such as glycolysis and the TCA cycle, whereas telethonin, filamin, nebulin, desmin, and ACTA1 contribute to the muscle contractile apparatus, and PI4-K, CamK II, and ICER have roles in signal transduction pathways regulated by growth factor or hormones. The final three genes, NID-2, WDNMI, and ferritin, are involved in iron transport and extracellular protein inhibition. The expression patterns were confirmed for seven genes (MDH, PI4-K, ferritin, ICER, nebulin, WDNMI, and telethonin) using real-time PCR. We found that the novel transcription repressor ICER gene was highly expressed in the late fattening stage and during bovine preadipocyte differentiation. This information may be helpful in selecting candidate genes that participate in intramuscular fat development in cattle.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.4
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• pp.567-573
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• 2014

Hormonal and nutrient signals regulate leptin synthesis and secretion. In rodents, leptin is stored in cytosolic pools of adipocytes. However, not much information is available regarding the regulation of intracellular leptin in ruminants. Recently, we demonstrated that leptin mRNA was expressed in bovine intramuscular preadipocyte cells (BIP cells) and that a cytoplasmic leptin pool may be present in preadipocytes. In the present study, we investigated the expression of cytoplasmic leptin protein in BIP cells during differentiation as well as the effects of various factors added to the differentiation medium on its expression in BIP cells. Leptin mRNA expression was observed only at 6 and 8 days after adipogenic induction, whereas the cytoplasmic leptin concentration was the highest on day 0 and decreased gradually thereafter. Cytoplasmic leptin was detected at 6 and 8 days after adipogenic induction, but not at 4 days after adipogenic induction. The cytoplasmic leptin concentration was reduced in BIP cells at 4 days after treatment with dexamethasone, whereas cytoplasmic leptin was not observed at 8 days after treatment. In contrast, acetate significantly enhanced the cytoplasmic leptin concentration in BIP cells at 8 days after treatment, although acetate alone did not induce adipocyte differentiation in BIP cells. These results suggest that dexamethasone and acetate modulate the cytoplasmic leptin concentration in bovine preadipocytes.

• Animal Bioscience
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• v.36 no.2
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• pp.175-190
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• 2023

Objective: The study was conducted to screen differentially expressed long noncoding RNA (lncRNA) in chickens by high-throughput sequencing and explore its mechanism of action on intramuscular fat deposition. Methods: Herein, Rose crown and Cbb broiler chicken embryo breast and leg muscle lncRNA and mRNA expression profiles were constructed by RNA sequencing. A total of 96 and 42 differentially expressed lncRNAs were obtained in Rose crown vs Cobb broiler chicken breast and leg muscle, respectively. lncRNA-ENSGALT00000046546, with high interspecific variability and a potential regulatory role in lipid metabolism, and its predicted downstream target gene 1-acylglycerol-3-phosphate-O-acyltransferase 2 (AGPAT2), were selected for further study on the preadipocytes. Results: lncRNA-46546 overexpression in chicken preadipocyte 2 cells significantly increased (p<0.01) the expression levels of AGPAT2 and its downstream genes diacylglycerol acyltransferase 1 and diacylglycerol acyltransferase 2 and those of the fat metabolism-related genes peroxisome proliferator-activated receptor γ, CCAAT/enhancer binding protein α, fatty acid synthase, sterol regulatory element-binding transcription factor 1, and fatty acid binding protein 4. The lipid droplet concentration was higher in the overexpression group than in the control cells, and the triglyceride content in cells and medium was also significantly increased (p<0.01). Conclusion: This study preliminarily concludes that lncRNA-46546 may promote intramuscular fat deposition in chickens, laying a foundation for the study of lncRNAs in chicken early embryonic development and fat deposition.

• Journal of Animal Science and Technology
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• v.47 no.6
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• pp.1087-1094
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• 2005

The uptake of glucose for metabolism and growth is essential to most animal cells and is mediated by glucose transport protein. In the glucose transport protein family, GLUT4 plays a key role in cellular glucose uptake stimulated by insulin in skeletal muscles and adipose tissue in rodents and human. In this studies, we reported the identification, characterization, and expression of Hanwoo GLUT4 gene. The Hanwoo GLUT4 cDNA includes a 1527 bp open reading frame encoding a protein of 509 amino acids. The GLUT4 amino acid sequences of the Hanwoo show strong conservation with the corresponding sequences reported in other species. The highest mRNA expression of GLUT4 was detected in heart and lower expression was detected in rib meat, sirloin, and colon. We confirmed the expression of GLUT4 in the subcutaneous and small intestinal adipose tissue using RT-PCR. To investigate the expression of GLUT4 in the bovine intramuscular adipose differentiation, fibroblast-like cells were isolated from the sirloin of Hanwoo bull aged 12 months by collagenase digestion of minced tissue and cultured with activators of PPAR gamma. We identified that GLUT4 mRNA expression decreased during differentiation of preadipocytes into adipocyte in Korean cattle. These results indicated that function of GLUT4 in bovine adipose tissue was different from that of mouse and human.