Duhak Yoon

Proteins in longissimus muscle of Korean native cattle and their relationship to meat quality

Proteomic profiling by two-dimensional gel electrophoresis and mass spectrometry of longissimus dorsi muscle tissue from Korean native cattle identified seven proteins that are differentially expressed in animals producing low and high quality grade beef. The expression level of alpha actin is increased in high quality grade beef and the expression levels of T-complex protein 1 (TCP-1), heat shock protein beta-1 (HSP27), and inositol 1,4,5-triphosphate receptor type1 (IP3R1), a new protein to be associated with meat quality, are increased in low quality grade beef. In particular, the quantitation of HSP27 and IP3R1 by both silver staining and immunoblotting correlated well with intramuscular fat content, meat tenderness, and free calcium levels. The data suggest that HSP27 and IP3R1 are potential meat quality biomarkers and their identification provides new insight into the molecular mechanisms and pathways associated with overall beef quality.

Proteomic analysis of bovine omental, subcutaneous and intramuscular preadipocytes during in vitro adipogenic differentiation.

Given the substantial rise in obesity, depot-specific fat accumulation and its associated diseases like diabetes, it is important to understand the molecular basis of depot-specific adipocyte differentiation. Many studies have successfully exploited the adipocyte differentiation, but most of them were not related to depot-specificity, particularly using freshly isolated primary preadipocytes. Using 2-dimensional polyacrylamide gel electrophoresis coupled with sequencing mass spectrometry, we searched and compared the proteins differentially expressed in undifferentiated and differentiated preadipocytes from bovine omental, subcutaneous and intramuscular adipose depots. Our proteome mapping strategy to identify differentially expressed intracellular proteins during adipogenic conversion revealed 65 different proteins that were found to be common for the three depots. Further, we validated the differential expression for a subset of proteins by immunoblotting analyses. The results demonstrated that many structural proteins were down-regulated during differentiation of preadipocytes from all the depots. Most up-regulated proteins like Ubiquinol-cytochrome-c reductase complex core protein I (UQCRC1), ATP synthase D chain, Superoxide dismutase (SOD), Glyceraldehyde-3-phosphate dehydrogenase (GAPDH), Sulfotransferase 1A1 (SULT1A1), Carnitine O-palmitoyltransferase 2 (CPT2) and Heat-shock protein beta 1 (HSPB1) across the three depots were found to be associated with lipid metabolism and metabolic activity. Further, all the up-regulated proteins were found to have higher protein expression in omental than subcutaneous or intramuscular depots.

Comparative studies of skeletal muscle proteome and transcriptome profilings between pig breeds

Two genetically different pig breeds, the Korean native pig (KNP) and the Western meat-producing Landrace, show breed-specific traits in stress responsiveness (stress hormone levels), growth performance (live weight), and meat quality (intramuscular fat content). We analyzed expression levels within the proteome and transcriptome of the longissimus muscles of both breeds using two-dimensional electrophoresis (2-DE) and microarray analysis. We constructed a porcine proteome database focused mainly on mitochondrial proteins. In total, 101 proteins were identified, of which approximately 60% were metabolic enzymes and mitochondrial proteins. We screened several proteins and genes related to stress and metabolism in skeletal muscles using comparative analysis. In particular, three stress-related genes (heat shock protein β-1, stress-70 protein, and heat shock 70xa0kDa protein) were more highly expressed in the Landrace than in the KNP breed. Six metabolism-related genes (peroxisome proliferative activated receptor α, short-chain acyl-CoA dehydrogenase, succinate dehydrogenase, NADH-ubiquinone oxidoreductase, glycerol-3-phosphate dehydrogenase, and sterol regulatory element binding protein-1c), all of which are involved in energy and lipid metabolism, were more highly expressed at the protein or mRNA level in the KNP breed. These data may reflect the breed dependence of traits such as stress responsiveness, growth performance, and meat quality.

IL-17A promotes transdifferentiation of mouse myoblast cells (C2C12) into adipocytes by increasing the expression of peroxisome proliferator-activated receptor γ through CAAT/enhancer binding protein β signaling

Purpose of workHelper 17 T (Th17) effector cells are a recently identified Th subset and possess a unique property that distinguishes them from Th1 and Th2 subsets. The functional role of Th17 effector cells involves inflammatory responses, including autoimmunity and infection of specific pathogens. Therefore, IL-17A and its receptors may play a key role in determining the progression of certain inflammatory reactions. However, the relationship between IL-17A and adipogenesis has not yet been examined. Therefore, in this study, the effect of IL-17A on the adipogenic transdifferentiation of mouse myoblast (C2C12) cells was examined.CAAT/enhancer binding-protein β (C/EPBβ) signaling through the IL-17A receptor promoted adipogenic transdifferentiation of myoblast cells by activating peroxisome proliferator-activated receptor γ (PPARγ). These results will advance our understanding of the physiological function of IL-17A in myoblasts during inflammation, as well as the relationship between adipogenesis and inflammation.

Association of Succinate Dehydrogenase and Triose Phosphate Isomerase Gene Expression with Intramuscular Fat Content in Loin Muscle of Korean (Hanwoo) Cattle

In a previous study, succinate dehydrogenase (SDH) and triose phosphate isomerase (TPI) were detected by 2D gel electrophoresis as differentially expressed proteins in the longissimus thoracis muscles of cattle aged between 12 and 27 months old. In the present study, we investigated the association of SDH and TPI gene expression with intramuscular fat content in 50 Hanwoo steers. The SDH gene was expressed at a 4 times higher level in the 12 month old group than in the 27 month old group (p

Gene Expression Analysis of Inducible cAMP Early Repressor (ICER) Gene in Longissimus dorsi of High- and Low Marbled Hanwoo Steers

Marbling (intramuscular fat) is an important factor in determining meat quality in Korean beef market. A grain based finishing system for improving marbling leads to inefficient meat production due to an excessive fat production. Identification of intramuscular fat-specific gene might be achieved more targeted meat production through alternative genetic improvement program such as marker assisted selection (MAS). We carried out ddRT-PCR in 12 and 27 month old Hanwoo steers and detected 300 bp PCR product of the inducible cAMP early repressor (ICER) gene, showing highly gene expression in 27 months old. A 1.5 kb sequence was re-sequenced using primer designed base on the Hanwoo EST sequence. We then predicted the open reading frame (ORF) of ICER gene in ORF finder web program. Tissue distribution of ICER gene expression was analysed in eight Hanwoo tissue using realtime PCR analysis. The highest ICER gene expression showed in Small intestine followed by Longissimus dorsi. Interestingly, the ICER gene expressed 2.5 time higher in longissimus dorsi than in same muscle type, Rump. For gene expression analysis in high- and low marbled individuals, we selected 4 and 3 animal based on the muscle crude fat contents (high is 17-32%, low is 6-7% of crude fat contents). The ICER gene expression was analysed using ANOVA model. Marbling (muscle crude fat contents) was affected by ICER gene (P