Transcriptome shifts triggered by vitamin A and SCD genotype interaction in Duroc pigs

Fatty acid composition of beef intramuscular tissue is an important trait because high proportions of mono-unsaturated fatty acid are related to favorable beef flavor. In this study, we investigated the effects of genetic factors, such as stearoyl-CoA desaturase (SCD), on beef carcass traits, including fatty acid composition, in the Hanwoo. Analysis of fatty acids in Hanwoo was performed using a breed raised in Gyeonbuk province (n = 395). Compared to the homozygote, the GA, CT, and CT genotypes of exon 5 in the SCD polymorphism showed a higher content of oleic acid (p<0.05) and higher contents of mono-unsaturated fatty acid (p<0.05) and marbling scores (p<0.05) in intramuscular fat. Results of haplotype analysis showed a significant presence of unsaturated fatty acids and marbling score in the ht1*ht2 and ht2*ht2 groups (p<0.05). Furthermore, haplotype effects more powerful than a single gene were also observed. These ht1 and ht2 types also showed a significant difference in unsaturated fatty acids and marbling score, affecting beef flavor in the Hanwoo groups. Therefore, it can be inferred that the ht1 and ht2 types might be valuable new markers for use in improvement of Hanwoo. (Key Words : Hanwoo, Unsaturated Fatty Acid, Stearoyl-CoA Desaturase(SCD), Haplotype, Beef Flavor)

Skeletal muscle gene expression and meat quality of F1 Angus–Nellore young steers and bulls feedlot finished

This study aimed to determine the relationship between intramuscular fat (IMF) content and fatty acid (FA) composition of pork. The IMF content and the FA composition were determined in the samples (n = 30) of muscle tissue (m. longissimus dorsi) taken from the pig carcasses from the intensive pork production system in Republic of Croatia. The fat content was analysed by standard ISO method, while FA composition was determined by liquid gas chromatography using the in situ transesterification method. Results revealed the significant positive correlations and regressions of monounsaturated FA (MUFA) on IMF content, while reverse relationship existed between IMF and the most of the polyunsaturated FA (PUFA). Although there was a significant relation between the IMF content and the majority of individual saturated FA (SFA), the effect of IMF content on the proportion of total SFA in pork was not clear. This can be explained by the existence of significant correlations and regressions but with an opposite directions for major SFA-s, which shares in IMF were simultaneously increasing (e.g. 16:0) and decreasing (e.g. 18:0) with an increase in IMF content.

The objectives of this study were 1) to determine whether selection toward less subcutaneous fat thickness at constant intramuscular fat content in pigs is related to tissue-specific changes in the expression of lipogenic enzymes acetyl-CoA carboxylase (ACC), stearoyl-CoA desaturase (SCD), and Delta(6)-desaturase (Delta6d); and 2) to investigate tissue specific distribution of the porcine ACC, SCD, and Delta6d. The study was conducted on 20 purebred Duroc barrows. Ten animals were from a group selected for decreased subcutaneous fat thickness at constant intramuscular fat content (experimental group). The other 10 animals were from the unselected (control) group. Distribution of ACC, SCD, and Delta6d was investigated in semimembranosus muscle (SM), subcutaneous adipose tissue (SA), liver (L), kidney (K), heart (H), diaphragm (D), rectus capitis muscle (RCM), and abdominal fat (AF). The enzyme expression was studied in 10 animals in the case of SM and SA and in 4 animals in the case of other tissues. The following expression pattern was established for ACC: SM <or= H = K <or= D < RCM < L < AF = SA, whereas the expression patterns for SCD and Delta6d proteins were SM < H < RCM < D < L < K < AF = SA and RCM = SM = D < L <or= H < SA < K < AF, respectively. Expression of ACC and SCD proteins was less in subcutaneous adipose tissue of the experimental animals when compared with the control group (P < 0.001). However, no difference (P > 0.1) in ACC and SCD protein expression between the control and experimental groups was observed in SM. Expression of Delta6d protein did not differ between the control and experimental groups for SA (P = 0.47) or SM (P = 0.31). There was a positive relationship between muscle SCD protein expression and intramuscular fat content (r = 0.48, P < 0.05). Intramuscular fat content did not correlate with ACC or Delta6d protein expression (P = 0.23 and P = 0.80, respectively). We conclude that SCD might be an effective potential biomarker for intramuscular fat deposition.

Simple SummaryCirculating non-esterified fatty acids (NEFA) may be valuable as biomarkers for intramuscular fat content and fatty acid composition, as well as for other meat quality traits, in finishing heavy Duroc pigs. However, circulating NEFA composition may be affected by other factors such as age, fasting duration, and genetic variants related with adipogenesis and fatty acid metabolism pathways (e.g., SCD and LEPR). This study revealed that the circulating NEFA composition, especially the oleic acid content, reflects the metabolic status of an animal at a given time but has limited value as biomarker of intramuscular fat content and fatty acid composition.Circulating non-esterified fatty acids (NEFA) can reflect the composition of dietary fat or adipose tissues depending on the fasting conditions. Therefore, circulating NEFA may be valuable as biomarkers for meat quality traits, such as intramuscular fat content and fatty acid composition in finishing pigs. Genetic variants that regulate lipid metabolism can also modulate the circulating NEFA. We conducted an experiment with 150 heavy Duroc pigs to evaluate fluctuations in the circulating NEFA composition due to age, fasting duration and two genetic polymorphisms, one in the leptin receptor (LEPR; rs709596309) and one in the stearoyl-CoA desaturase (SCD; rs80912566) gene. Circulating NEFA were more saturated and less monounsaturated than the subcutaneous and intramuscular adipose tissues. Absolute circulating NEFA content was more influenced by fasting duration than age. The SCD polymorphism did not impact NEFA content or composition. The LEPR polymorphism affected the content but not the fatty acid composition. Circulating oleic acid NEFA content after a short fasting was positively correlated with intramuscular fat content and, after a long fasting, with intramuscular oleic acid content. We conclude that circulating NEFA reflect environmental and genetic metabolic changes but are of limited value as biomarkers for intramuscular fat content and fatty acid composition.

With three-dimensional growth conditions, multicellular tumor spheroids reproduce several parameters of the tumor microenvironment, including oxygen and nutrient gradients, characteristic of poorly vascularized tumor regions. 3D high content screening (HCS) identified compounds that selectively kill tumor cells in the inner core of tumor cell spheroids by targeting the Stearoyl CoA Desaturase 1 (SCD1) pathway. SCD1 catalyzes the rate-limiting step in the production of mono-unsaturated fatty acids (MUFAs). Cancer cells are dependent on higher levels of MUFAs compared to normal cells and SCD1 is highly expressed in multiple tumor types. Changes in the MUFA / SFA (saturated fatty acid) ratio alters lipid biosynthesis and thus triggers cellular (ER) stress and induces the Unfolded Protein Response. Although the lead compound was very effective in vitro, it had unfavorable PK and physical chemistry properties, including low permeability and solubility and very high lipophilicity. This led to insufficient oral bioavailability, which could be overcome by optimization of PK and physical chemistry properties. Here, we report on the in vitro/in vivo effects of our 3D HCS compounds which showed high potency in the 3D spheroid inner core death assay with T47D breast cancer cells. In this in vitro model compound-induced inner core cell death is enhanced by SCD1 substrates palmitic or stearic acid and rescued by the SCD1 products palmitoleic or oleic acid. Furthermore, the effects can be reproduced in 2D cultures, which become increasingly sensitive to inhibition by our 3D HCS compounds with decreasing FBS concentration in the culture medium and this effect can also be rescued by addition of MUFAs but not of palmitic acid. Mode of action analysis showed that our compounds reduced palmitoleoyl- or oleoyl-CoA levels and simultaneously increased saturated fatty acyl-CoAs of palmitate or stearate in several cell lines as well as in vivo. In the sensitive T47D cells, the compounds induced expression of stress response genes and genes related to lipid metabolism. While these results support the SCD1 pathway as target for our 3D HCS compounds, we also observed striking differences to published SCD1 inhibitors suggesting a new cancer target beyond SCD1. Thus, further validation of our inhibitors in vitro and in vivo will be required, but these results suggest that 3D spheroid cultures may be a valuable tool for elucidation of new drug targets for cancer therapy. Citation Format: Sylvia Gruenewald, Carolyn Sperl, Patrick Steigemann, Alexander Walter, Sylvia Zacharias, Uwe Eberspaecher, Roland Neuhaus, Ludwig Zorn, Wolfgang Schwede, Kai Thede, Sven Christian. 3D spheroid screen yields SCD1 pathway inhibitors for the treatment of cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4989. doi:10.1158/1538-7445.AM2017-4989

Milkfish, a commercially important culture teleost in Taiwan, are known to be less tolerant to the cold, and the culture industry in this country has often suffered from the mass mortality of winterkills. The membrane lipid desaturation and stearoyl-CoA desaturase expression in milkfish under cold shock were investigated. Milkfish were initially acclimated at 25℃ and then exposed to cold shock of 15℃. The proportions of saturated fatty acids (16: 0 and 18: 0) in the hepatic microsomes of milkfish at 15℃ were lower, while those of monounsaturated fatty acids (16: 1 and 18: 1) were significantly higher than the control fish at 25℃. Δ^9 desaturation index gradually increased in the early period of cold shock and peaked on day 5, followed by slight decrease thereafter. Concurrent changes in Δ^9 desaturation index (16: 1/16: 0 and 18: 1/18: 0) and the proportion of fatty acids in the hepatic microsomes of milkfish were further demonstrated. The trend of stearoyl-CoA desaturase activity changes was found parallel to those of unsaturated fatty acids composition and Δ^9 desaturation index, though 1-day time lag was evident. These parameters are significantly correlated among them, and Δ^9 desaturation index can accordingly be employed to represent the degree of fatty acid desaturation, stearoyl-CoA desaturase activities and membrane fluidity as well. The expression of stearoyl-CoA desaturase mRNA in milkfish is specifically induced by a low temperature, and those in stearoyl-CoA desaturase activities were parallel to the changes in desaturase mRNA transcript. The findings suggested that the increases in the membrane lipid desaturation and stearoyl-CoA desaturase activities in milkfish under cold shock were in accordance with other teleosts being reported elsewhere, and the quantitative compensatory mechanisms are predominantly involved in the acclimation process of cold shock in this species.

Machine learning-enabled fatty acid quantification and classification of pork from autochthonous breeds using low-field 1H NMR spectroscopic data

A reduced protein diet (RPD) is known to increase the level of intramuscular lipid in pig meat with a smaller effect on the amount of subcutaneous adipose tissue. This might be due to tissue-specific activation of the expression of lipogenic enzymes by the RPD. The present study investigated the effect of a RPD, containing palm kernel oil, soyabean oil or palm oil on the activity and expression of one of the major lipogenic enzymes, stearoyl-CoA desaturase (SCD) and on the level of total lipids and the fatty acid composition of muscle and subcutaneous adipose tissue in pigs. The RPD significantly increased SCD protein expression and activity in muscle but not in subcutaneous adipose tissue. The level of MUFA and total fatty acids in muscle was also elevated when the RPD was fed, with only small changes in subcutaneous adipose tissue. A positive significant correlation between SCD protein expression and total fatty acids in muscle was found. The results suggest that an increase in intramuscular but not subcutaneous adipose tissue fatty acids under the influence of a RPD is related to tissue-specific activation of SCD expression. It is suggested that the SCD isoform spectra in pig subcutaneous adipose tissue and muscle might be different.

The objective of this research was to evaluate the effect of dietary conjugated linoleic acid (CLA) enrichment for finishing heavy fatty pigs on performance, carcass traits and fatty acid composition in subcutaneous and intramuscular fat (IMF), including CLA main isomers concentration. Forty castrated Iberian × Duroc pigs, half males and half females, with 120 (±2.83) kg live weight were used. Pigs were fed experimental diets containing two levels (0 and 1%) of CLA. No effect of CLA was observed on backfat thickness or IMF concentration. In subcutaneous backfat, dietary CLA increased the C16:0, C18:0, c9,t11-CLA , t10,c12-CLA and saturated fatty acids (SFA) proportion and decreased those C18:1 n-9, C18:2 n-6, monounsaturated fatty acids (MUFA), polyunsaturated fatty acids (PUFA) proportions and MUFA/SFA and C18:1 n-9/C18:0 and C16:1 n-7/C16:0 ratios. In the IMF, dietary CLA increased C16:0, SFA, c9,t11 and t10,c12 proportions and reduced C18:1 n-9 and MUFA, MUFA/SFA and C18:1 n-9/C18:0 ratios, but showed no effect on C18:2 n-6 and PUFA proportion. Subcutaneous backfat fatty acid profile was affected by gender, but no gender effect on intramuscular fatty acid profile was observed. CLA isomer accumulation was lower in heavy pigs compared to the lean genotype probably as a consequence of the higher carcass fat concentration in the former.

ENO1 promotes Acute Myeloid Leukemia progression through SCD1-mediated lipid metabolism reprogramming

Effect of low- and high-forage diets on meat quality and fatty acid composition of Alentejana and Barrosã beef breeds

The aim of this study was to determine the optimum carcass weight for meat quality and fatty acid composition in fat-tailed Chall lambs. Thirty lambs (15 male and 15 female) were allotted to three carcass weight groups: (1) light carcass weight (LCW 10-15kg), (2) moderate carcass weight (MCW 15-20kg), and (3) heavy carcass weight (HCW 20-25kg). Back fat thickness and intramuscular fat (IMF) content were greater (P < 0.05) for HCW and female groups than their counterparts, respectively. Drip loss was lower (P < 0.05) for female and HCW lamb groups than male and LCW group, respectively. Female and LCW lambs had lower (P < 0.05) shear force compared with their corresponding male and HCW groups. Meat from LCW and MCW lambs had higher lightness (L* value; 43.6, 43.5 vs. 39.9), while redness (a* value; 13.6, 13.9 vs. 15.4) was greater for HCW and female (13.7 vs. 14.9) lambs compared with their counterparts (P < 0.05). The MCW lambs produced meat with higher overall acceptability compared with other two groups (P < 0.05). The HCW lambs contained lower polyunsaturated fatty acids (PUFA), polyunsaturated fatty acids to saturated fatty acids (P:S) ratio, and n-3 PUFA compared with LCW group (P < 0.05). Results show that as the animal grow faster and achieved HCW, the IMF content also increased mainly as storage triglyceride, while functional fats consisting long-chain omega-3 did not increase proportionately. In addition, the study also demonstrates that using IMF for predicting or assessing meat quality aspects such as juiciness and flavor or the nutritional value of meat relating to health claimable fatty acids would not be appropriate.

&lt;div&gt;Abstract&lt;p&gt;The redeployed drug combination of bezafibrate and medroxyprogesterone acetate (designated BaP) has potent &lt;i&gt;in vivo&lt;/i&gt; anticancer activity in acute myelogenous leukemia (AML) and endemic Burkitt lymphoma (eBL) patients; however, its mechanism-of-action is unclear. Given that elevated fatty acid biosynthesis is a hallmark of many cancers and that these drugs can affect lipid metabolism, we hypothesized that BaP exerts anticancer effects by disrupting lipogenesis. We applied mass spectrometry–based lipidomics and gene and protein expression measurements of key lipogenic enzymes [acetyl CoA carboxylase 1 (ACC1), fatty acid synthase (FASN), and stearoyl CoA desaturase 1 (SCD1)] to AML and eBL cell lines treated with BaP. BaP treatment decreased fatty acid and phospholipid biosynthesis from &lt;sup&gt;13&lt;/sup&gt;C D-glucose. The proportion of phospholipid species with saturated and monounsaturated acyl chains was also decreased after treatment, whereas those with polyunsaturated chains increased. BaP decreased SCD1 protein levels in each cell line (0.46- to 0.62-fold; &lt;i&gt;P&lt;/i&gt; &lt; 0.023) and decreased FASN protein levels across all cell lines (0.87-fold decrease; &lt;i&gt;P&lt;/i&gt; = 1.7 × 10&lt;sup&gt;−4&lt;/sup&gt;). Changes to ACC1 protein levels were mostly insignificant. Supplementation with the SCD1 enzymatic product, oleate, rescued AML and e-BL cells from BaP cell killing and decreased levels of BaP-induced reactive oxygen species, whereas supplementation with the SCD1 substrate (and FASN product), palmitate, did not rescue cells. In conclusion, these data suggest that the critical anticancer actions of BaP are decreases in SCD1 levels and monounsaturated fatty acid synthesis. To our knowledge, this is the first time that clinically available antileukemic and antilymphoma drugs targeting SCD1 have been reported. &lt;i&gt;Cancer Res; 75(12); 2530–40. ©2015 AACR&lt;/i&gt;.&lt;/p&gt;&lt;/div&gt;

Intramuscular fat (IMF) content is crucial for meat quality, and genetic, environmental, and nutritional factors influence its deposition. This study aims to identify genes involved in the regulation of IMF deposition in Guizhou Yellow Chickens. Thirty Guizhou Yellow Chicken hens aged 120 days were selected, and their IMF content was measured using the Soxhlet extraction method. The IMF content was divided into a high IMF group (H group, n = 4) and a low IMF group (L group, n = 4). RNA-seq was performed on the H and L groups to screen out signaling pathways and key genes that affect IMF deposition. A total of 259 differentially expressed genes(DEGs) were screened, including 195 that were up-regulated and 64 that were down-regulated. Critical genes such as COL1A1, COL1A2, COL6A3, PLTP, LPIN1, ITGA8, and FN1 were identified as key influencers of IMF deposition in Guizhou Yellow Chickens. The slow virus interference vector has demonstrated that interfering with COL1A1 can inhibit the proliferation ability of chicken preadipocytes and reduce lipid droplet accumulation. In addition, interference with COL1A1 significantly inhibited the expression of PLTP, ABHD6, LPIN1, and PTGS2 and decreased the levels of triglycerides and cholesterol at 4 and 8 days. The results further showed that COL1A1 is a key gene in the gene regulatory network during fat deposition, and the interaction of these genes affects the proliferation and differentiation of fat cells, thereby reducing the accumulation of fat droplets in muscle fibers. This study indicates that the COL1A1 gene is associated with IMF formation in Guizhou Yellow Chickens, providing a critical gene for selecting markers to control IMF formation and laying a foundation for future poultry meat quality breeding.