Subcutaneous Fat Gene Research Articles

Screening of Genes Related to Fat Deposition of Pekin Ducks Based on Transcriptome Analysis.

Subcutaneous fat deposition is an important index with which to evaluate meat-producing ducks, and affects their meat quality and feed conversion rate. Studying the differentially expressed genes in subcutaneous fat will help to comprehensively understand the potential mechanisms regulating fat deposition in ducks. In this study, 72 Nankou 1 Pekin Ducks and 72 Jingdian Pekin Ducks (half male and half female) at 42 days of age were selected for slaughter performance and transcriptome analysis. The results showed that the breast-muscle yield of Nankou 1 ducks was significantly higher than that of Jingdian ducks, but that the abdominal fat yield and subcutaneous fat yield were higher than that of Jingdian ducks. Thousands of DEGs, including many important genes involved in fat metabolism regulation, were detected by transcriptome. KEGG enrichment analysis showed that the DEGs were significantly enriched on pathways such as regulation of lipolysis in adipocytes, primary bile acid biosynthesis, and biosynthesis of unsaturated fatty acids. SCD, FGF7, LTBP1, PNPLA3, ADCY2, and ACOT8 were selected as candidate genes for regulating subcutaneous fat deposition. The results indicated that Nankou 1 had superior fat deposition ability compared to Jingdian ducks, and that the candidate genes regulated fat deposition by regulating fat synthesis and decomposition.

Fat deposition, fatty acid profiles, antioxidant capacity and differentially expressed genes in subcutaneous fat of Tibetan sheep fed wheat-based diets with and without xylanase supplementation.

Xylanase, an exogenous enzyme that plays an essential role in energy metabolism by hydrolysing xylan into xylose, has been shown to positively influence nutrient digestion and utilisation in ruminants. The objective of this study was to evaluate the effects of xylanase supplementation on the back-fat thickness, fatty acid profiles, antioxidant capacity, and differentially expressed genes (DEGs)in the subcutaneous fat of Tibetan sheep. Sixty three-month-old rams with an average weight of 19.35 ± 2.18 kg were randomly assigned to control (no enzyme added, WH group) and xylanase (0.2% of diet on a dry matter basis, WE group) treatments. The experiment was conducted over 97 d, including 7 d of adaption to the diets. The results showed that xylanase supplementation in the diet increased adipocyte volume of subcutaneous fat (p < 0.05), shown by hematoxylin and eosin (H&E) staining. Gas chromatography showed greater concentrations of C14:0 and C16:0 in the subcutaneous fat of controls compared with the enzyme-treated group (p < 0.05), while opposite trend was seen for the absolute contents of C18:1n9t, C20:1, C18:2n6c, C18:3, and C18:3n3 (p < 0.05). Compared with controls, supplementation with xylanase increased the activity of T-AOC significantly (p < 0.05). Transcriptomic analysis showed the presence of 1630 DEGs between the two groups, of which 1023 were up-regulated and 607 were down-regulated, with enrichment in 4833 Gene Ontology terms, and significant enrichment in 31 terms (p < 0.05). The common DEGs were enriched in 295 pathways and significantly enriched in 26 pathways. Additionally, the expression of lipid-related genes, including fatty acid synthase, superoxide dismutase, fatty acid binding protein 5, carnitine palmytoyltransferase 1 A, and peroxisome proliferator-activated receptor A were verified via quantitative reverse-transcription polymerase chain reaction. In conclusion, dietary xylanase supplementation was found to reduce subcutaneous fat deposition in Tibetan sheep, likely through modulating the expression of lipid-related genes.

Comparative Transcriptome Analysis Provides Insight into Spatio-Temporal Expression Characteristics and Genetic Regulatory Network in Postnatal Developing Subcutaneous and Visceral Fat of Bama Pig.

The depot differences between Subcutaneous Fat (SAF) and Visceral Fat (VAF) are critical for human well-being and disease processes in regard to energy metabolism and endocrine function. Miniature pigs (Sus scrofa) are ideal biomedical models for human energy metabolism and obesity due to the similarity of their lipid metabolism with that of humans. However, the regulation of differences in fat deposition and development remains unclear. In this study, the development of SAF and VAF was characterized and compared in Bama pig during postnatal development (infancy, puberty and adulthood), using RNA sequencing techniques (RNA-Seq). The transcriptome of SAF and VAF was profiled and isolated from 1-, 3- and 6 months-old pigs and identified 23,636 expressed genes, of which 1,165 genes were differentially expressed between the depots and/or developmental stages. Upregulated genes in SAF showed significant function and pathway enrichment in the central nervous system development, lipid metabolism, oxidation-reduction process and cell adhesion, whereas genes involved in the immune system, actin cytoskeleton organization, male gonad development and the hippo signaling pathway were preferentially expressed in VAF. Miner analysis of short time-series expression demonstrated that differentiation in gene expression patterns between the two depots corresponded to their distinct responses in sexual development, hormone signaling pathways, lipid metabolism and the hippo signaling pathway. Transcriptome analysis of SAF and VAF suggested that the depot differences in adipose tissue are not only related to lipid metabolism and endocrine function, but are closely associated with sexual development and organ size regulation.

Subcutaneous and intramuscular fat transcriptomes show large differences in network organization and associations with adipose traits in pigs.

Subcutaneous fat (SCF) and intramuscular fat (IMF) deposition is relevant to health in humans, as well as meat production and quality in pigs. In this study, we generated RNA sequence data for 122 SCF, 120 IMF, and 87 longissimus dorsi muscle (LDM) samples using 155 F6 pigs from a specially designed heterogeneous population generated by intercrossing four highly selected European commercial breeds and four indigenous Chinese pig breeds. The phenotypes including waist back fat thickness and intramuscular fat content were also measured in the 155 F6 pigs. We found that the genes in SCF and IMF differed largely in both expression levels and network connectivity, and highlighted network modules that exhibited strongest gain of connectivity in SCF and IMF, containing genes that were associated with the immune process and DNA double-strand repair, respectively. We identified 215 SCF genes related to kinase inhibitor activity, mitochondrial fission, and angiogenesis, and 90 IMF genes related to lipolysis and fat cell differentiation, displayed a tissue-specific association with back fat thickness and IMF content, respectively. We found that cis-expression QTL for trait-associated genes in the two adipose tissues tended to have tissue-dependent predictability for the two adipose traits. Alternative splicing of genes was also found to be associated with SCF or IMF deposition, but the association was much less extensive than that based on expression levels. This study provides a better understanding of SCF and IMF gene transcription and network organization and identified critical genes and network modules that displayed tissue-specific associations with subcutaneous and intramuscular fat deposition. These features are helpful for designing breeding programs to genetically improve the two adipose traits in a balanced way.

Forensic aspects of gene expression signatures for age determination in bruises as evaluated in an experimental porcine model.

Determining the age of bruises and the force used to inflict the trauma is of crucial importance in both human and veterinary forensic pathology. In the present study, the expression of more than 50 different genes in subcutaneous fat and muscle tissue from experimental bruises in pigs was investigated. The aim was to evaluate if expression signatures of selected genes were capable of determining bruises according to age and the force of impact. Eighteen experimental pigs were anesthetized, and on each animal four blunt traumas were inflicted on the back with a low, moderate or high force. The pigs were euthanized from 1 to 10h after infliction of the trauma and subcutaneous fat and muscle tissues were sampled. As control, subcutaneous fat and muscle tissues were sampled from two un-injured pigs. Quantitative real-time polymerase chain reaction was performed to evaluate mRNA expression of genes involved in inflammation, tissue damage and repair. Expression signatures of thirteen selected genes in subcutaneous fat but not in muscle tissue reflected the age of bruises with a precision of approximately ±2h. Moreover, the gene expression signature in the subcutaneous fat was to some extend able to separate bruises inflicted with different forces. Expression signatures of selected genes in the subcutaneous fat will increase the precision of the age determination of bruises in pigs. Further, due to the similarity of porcine and human skin physiology and immunity, these results might also provide valuable information in human forensic science.

Effect of finishing period length with α-tocopherol supplementation on the expression of vitamin E-related genes in the muscle and subcutaneous fat of light lambs

The aim of this study was to investigate how different finishing period lengths with α-tocopherol supplementation or alfalfa grazing affect mRNA expression levels of genes related to vitamin E metabolism in L. thoracis (LT) muscle and subcutaneous fat (SF) from lambs of the Rasa Aragonesa breed. Indoors, concentrate-fed light lambs (n=48) were supplemented with 500dl-α-tocopheryl acetate/kg concentrate for an average finishing period length of 0 (C), 10.7 (VE10d), 21.2 (VE20d) and, 32.3 (VE30d) days before slaughtering. Simultaneously, 8 lambs with their dams were alfalfa-grazed. The α-tocopherol affected in a short-term the expression of genes in LT muscle (ABCA1, LPL, APOE, and SREBP1) and SF (ABCA1, SCARB1, LPL, and PPARG). On the contrary, PPARA gene expression showed a long-term α-tocopherol effect because the highest levels of PPARA mRNA were found in the VE30d.

Abstract 465: AT 2 Receptor Signaling Plays An Important Role In Conversion Of From White To Beige Fat

Background: We have previously reported that treatment with angiotensin II type-2 (AT 2 ) receptor agonist (compound 21; C21) ameliorated insulin resistance with the improvement of adipocyte dysfunction in obese type 2 diabetic mouse model, KKAy. Until quite recently, adipose tissue has been divided into two groups that have directory-opposed capacities; white adipose tissue is best known for its role in energy store, while brown adipose tissue functions for energy expenditure (thermogenesis). In addition, new clusters of adipocyte with thermogenic capability have been discovered in white adipose tissue, which are distinct origins from brown adipose tissue. These adipocytes have been named ‘beige’. However, the role of AT 2 receptor signaling in white-to-beige fat conversion is not known. Methods: KKAy mice were subjected to i.p. injection of C21 (10ug/kg/day) for 2 weeks. After the treatment, the expression of thermogenic genes (Ucp1, Cidea, Pgc1α) in adipose tissue were determined with real-time RT-PCR. Next, we examined the difference in conversion from white to beige fat between wild-type (WT) mice and AT 2 receptor knockout (AT 2 KO) mice. Eight-week-old mice were fed a high-fat and high-cholesterol diet (HFCD) (10% coconut oil + 1.25% cholesterol) for 2 weeks. To examine the effect of exercise on fat conversion, 9-week-old mice were forced swim test (2 minх3 times/day) for 7days. After the swim test, mice were sacrificed for examinations. Results: In KKAy mice, treatment of C21 increased the expression of thermogenic genes in subcutaneous fat, but not in visceral fat. Adipose tissue weight was not changed by treatment of C21. In AT 2 KO mice fed HFCD for 2 weeks, visceral fat was greater than that in WT mice, but subcutaneous fat was not. The expression of thermogenic genes in subcutaneous fat was lower in AT 2 KO mice than in WT mice. In both mice, swim exercise increased the expression of thermogenic genes; however, the up-regulation of these genes in AT 2 KO mice did not reach the level of that in WT mice. Conclusion: These results suggest that AT 2 receptor signaling has an important role in white-to-beige fat conversion, and therefore AT 2 receptor signaling might be a potential therapeutic target for lipid metabolic disorders.

Effects of bed-time insulin versus pioglitazone on abdominal fat accumulation, inflammation and gene expression in adipose tissue in patients with type 2 diabetes

Aims/hypothesis Intra-abdominal fat (IAF) and inflammatory markers are correlated with cardio-vascular risk. We compared the impact of bed-time insulin versus pioglitazone treatment on these parameters in type 2 diabetic (T2D) patients. Methods Twenty-eight T2D patients poorly controlled with metformin and sulfonylurea were randomized to receive add-on therapy with pioglitazone or bed-time NPH insulin. IAF and subcutaneous fat (SCF) content, systemic low-grade inflammation level and expression of inflammation related genes in SCF, were measured before and after 24 weeks of treatment. Results Insulin and pioglitazone resulted in a significant decrease in HbA1c (−1.6% and −1.2%, respectively) and a significant increase in total body fat mass (1 ± 2.3 and 3.3 ± 2.7 kg, respectively). There was no change in IAF content after both treatments whereas significant increase in SCF content was only seen after pioglitazone treatment ( p < 0.05 versus insulin). hsCRP level decreased after pioglitazone and ferritin level decreased after insulin treatment. No change in mRNA expression of inflammation related genes was found after either treatment. Conclusion/interpretation This suggests that a 24-week treatment with pioglitazone or bed-time insulin has a similar impact on intra-abdominal fat mass and systemic low-grade inflammation.