Genes Regulating Lipid Metabolism Research Articles

Nutritional condition drives spatial variation in physiology of Antarctic lipid-storing copepods.

Lipid-rich copepods form an essential link between primary producers and higher trophic levels in high-latitude oceans. These zooplankton can take advantage of ephemeral phytoplankton blooms to fuel development and reproduction. However, we have limited understanding of how the physiological condition of these animals varies in relation to environmental factors such as food availability. Due to high advection, it is likely that physiological plasticity, rather than local adaptation, is primarily responsible for physiological differences within a region. We use transcriptomics and other physiological metrics to understand how two species of copepods (Calanoides acutus and Calanus propinquus) vary across environmental gradients along the West Antarctic Peninsula. For the primarily herbivorous C. acutus, physiological separation between sampling locations appears to be driven by feeding status, and gene expression differences indicate differential expression of genes regulating lipid metabolism, reproduction, aerobic metabolism, and protein translation. For the more omnivorous C. propinquus, physiology and gene expression did not segregate as clearly by location, showed minimal signs of food deprivation at any location, and had a weaker relationship with chlorophyll compared to C. acutus. By comparing these results with concurrent starvation experiments, we find that spatial variation in gene expression reflects short-term differences in food availability (particularly for C. acutus), and we identify genes whose expression indicates recent feeding status. Further examination of the relationships between food availability, copepod physiology, and population dynamics will ultimately improve our capacity to predict how copepod populations will respond to rapidly changing environmental conditions in the West Antarctic Peninsula ecosystem.

Molecular signatures diversity unveiled through a comparative transcriptome analysis of longissimus dorsi and psoas major muscles in Hanwoo cattle

This study investigates the transcriptome-level alterations that influence production traits and early fattening stage myogenesis in Hanwoo cattle, specifically focusing on the highly prized Longissimus dorsi (LD) and Psoas major (PM) skeletal muscles, which hold significant commercial value. We conducted RNA sequencing analysis on LD and PM muscles from 14 Hanwoo steers (n = 7, each group) at the age of 10 months, all fed the same diet. Our results unveiled a total of 374 and 206 up-regulated differentially expressed genes (DEGs) in LD and PM muscles, respectively, with statistical significance (p < 0.05) and a log2fold change ≥ 1. Genes governing muscle development processes, such as PAX3, MYL3, COL11A1, and MYL6B, were found to be expressed at higher levels in both tissues. Conversely, genes regulating lipid metabolism, including FABP3, FABP4, LEP, ADIPOQ, and PLIN1, exhibited higher expression in the PM muscle. Functional enrichment analysis revealed a tissue-specific response, as PM muscle showed increased lipid metabolism allied pathways, including the PPAR signaling pathway and regulation of lipolysis in adipocytes, while LD was characterized by growth and proliferative processes. Our findings validate the presence of a muscle-dependent transcription and co-expression pattern that elucidates the transcriptional landscape of bovine skeletal muscle.

SUMOylated Golgin45 associates with PML-NB to transcriptionally regulate lipid metabolism genes during heat shock stress

Golgin tethers are known to mediate vesicular transport in the secretory pathway, whereas it is relatively unknown whether they may mediate cellular stress response within the cell. Here, we describe a cellular stress response during heat shock stress via SUMOylation of a Golgin tether, Golgin45. We found that Golgin45 is a SUMOylated Golgin via SUMO1 under steady state condition. Upon heat shock stress, the Golgin enters the nucleus by interacting with Importin-β2 and gets further modified by SUMO3. Importantly, SUMOylated Golgin45 appears to interact with PML and SUMO-deficient Golgin45 mutant functions as a dominant negative for PML-NB formation during heat shock stress, suppressing transcription of lipid metabolism genes. These results indicate that Golgin45 may play a role in heat stress response by transcriptional regulation of lipid metabolism genes in SUMOylation-dependent fashion.

Curcumin and saroglitazar attenuate diet-induced nonalcoholic steatohepatitis by activating the Nrf2 pathway and suppressing ERK1/2 signaling.

Non-alcoholic fatty liver disease (NAFLD) is a chronic steatohepatitis disorder. If left untreated, it can progress to hepatocellular carcinoma. Several studies have shown that saroglitazar, a PPARα/γ dual agonist, and curcumin (the principal constituent of turmeric) may be effective in the treatment of NAFLD. This research aimed to study the pharmacological mechanism of these compounds in rats with NAFLD. NAFLD was induced in male Wistar rats (aged 6-8 weeks) by feeding them a high-fat diet (HFD) for 6 weeks. Subsequently, the rats were divided into four groups, with Group 1 continuing on HFD, while groups 2, 3, and 4 received HFD supplemented with saroglitazar, curcumin, and both saroglitazar and curcumin, respectively. We evaluated the expression of Nrf2, ERK1/2, NOX1,2,4, antioxidant enzymes, PPARα, γ, and genes regulating lipid metabolism in the liver. Histopathology of liver tissue was also examined. Furthermore, we analyzed serum levels of lipid profiles and hepatic enzymes. Rats with NAFLD that received treatment involving saroglitazar and curcumin showed a significant decrease in the expression of ERK1/2, SREBP1, PPARγ, pro-inflammatory cytokines, NOXs, and ROS levels. Additionally, the levels of Nrf2, PPARα, and antioxidant enzymes showed a significant increase. The serum levels of lipid profiles and hepatic enzymes also decreased significantly after drug treatment. Our results confirm that both saroglitazar and curcumin ameliorate NAFLD by regulating the Nrf2 and ERK1/2 signaling pathways. These findings suggest that curcumin could serve as a suitable substitute for saroglitazar, although they appear to have a synergistic effect.

Lipid Metabolism and Improvement in Oilseed Crops: Recent Advances in Multi-Omics Studies.

Oilseed crops are rich in plant lipids that not only provide essential fatty acids for the human diet but also play important roles as major sources of biofuels and indispensable raw materials for the chemical industry. The regulation of lipid metabolism genes is a major factor affecting oil production. In this review, we systematically summarize the metabolic pathways related to lipid production and storage in plants and highlight key research advances in characterizing the genes and regulatory factors influencing lipid anabolic metabolism. In addition, we integrate the latest results from multi-omics studies on lipid metabolism to provide a reference to better understand the molecular mechanisms underlying oil anabolism in oilseed crops.

Association of TOP2A and ADH1B with lipid levels and prognosis in patients with lung adenocarcinoma and squamous cell carcinoma.

Although lung adenocarcinoma (LUAD) and lung squamous cell carcinoma (LUSC) have different pathological and clinical features, they may share common driver genes. It was found that lipid levels can be used for early diagnosis of NSCLC; however, the relationship between driver genes and genes regulating lipid metabolism and their relationship with patient prognosis needs further investigation. Genes whose expression was up- or down-regulated in both LUAD and LUSC were identified using the GEO database. Online tools like GEPIA 2, PrognoScan, UALCAN, and TIMER2.0 were used to investigate the association of these gene expressions with the patient's prognosis and lipid regulatory genes. The association between clinical lipid levels and the risk of LUAD and LUSC was analyzed by using a multiple logistic regression model. Topoisomerase II alpha (TOP2A) and alcohol dehydrogenase 1B (ADH1B) were identified as the only genes up- and down-regulated in both LUAD and LUSC. TOP2A and ADH1B expression levels significantly correlated with the patient's gender, age, individual cancer stage, histological subtype, nodal metastasis status, and TP53 mutation status. Additionally, only LUAD patients with higher TOP2A or lower ADH1B expressions displayed poor overall and relapse-free survival rates. Moreover, TOP2A levels exhibited a negative correlation with adipose triglyceride lipase (ATGL) and ATP-binding cassette transporter A1 (ABCA1) in both LUAD and LUSC. However, ADH1B showed inverse associations with the above-mentioned genes when compared to TOP2A expressions in both LUAD and LUSC. Furthermore, elevated triglyceride (OR = 1.59; 95% CI = 1.01 to 2.49; P < 0.05) and total cholesterol (OR = 2.45; 95% CI = 1.08 to 5.57; P < 0.05) levels might increase the risk of LUAD. TOP2A and ADH1B can be used as diagnostic markers for LUAD and LUSC, but only as independent prognostic factors for LUAD, and may be involved in lipid metabolism in LUAD patients but not in LUSC. Thus, combining genetic diagnostics with lipid panel tests might be an effective method for an early diagnosis and improved prognosis of LUAD.

Integrating distribution kinetics and toxicodynamics to assess repeat dose neurotoxicity in vitro using human BrainSpheres: a case study on amiodarone.

For ethical, economical, and scientific reasons, animal experimentation, used to evaluate the potential neurotoxicity of chemicals before their release in the market, needs to be replaced by new approach methodologies. To illustrate the use of new approach methodologies, the human induced pluripotent stem cell-derived 3D model BrainSpheres was acutely (48h) or repeatedly (7days) exposed to amiodarone (0.625-15µM), a lipophilic antiarrhythmic drug reported to have deleterious effects on the nervous system. Neurotoxicity was assessed using transcriptomics, the immunohistochemistry of cell type-specific markers, and real-time reverse transcription-polymerase chain reaction for various genes involved in the lipid metabolism. By integrating distribution kinetics modeling with neurotoxicity readouts, we show that the observed time- and concentration-dependent increase in the neurotoxic effects of amiodarone is driven by the cellular accumulation of amiodarone after repeated dosing. The development of a compartmental in vitro distribution kinetics model allowed us to predict the change in cell-associated concentrations in BrainSpheres with time and for different exposure scenarios. The results suggest that human cells are intrinsically more sensitive to amiodarone than rodent cells. Amiodarone-induced regulation of lipid metabolism genes was observed in brain cells for the first time. Astrocytes appeared to be the most sensitive human brain cell type in vitro. In conclusion, assessing readouts at different molecular levels after the repeat dosing of human induced pluripotent stem cell-derived BrainSpheres in combination with the compartmental modeling of in vitro kinetics provides a mechanistic means to assess neurotoxicity pathways and refine chemical safety assessment for humans.

O098 Diclofenac alters expression of genes regulating muscle lipid metabolism during resistance exercise training in humans, but does not change IMCL content

Abstract Introduction Diclofenac is an NSAID commonly used off-label to reputedly enhance athletic training adaptation. Diclofenac activates PPAR-γ and upregulates the expression of lipid metabolism genes in vitro. This study investigated the impact of diclofenac administration on IMCL content and muscle genes regulating lipid metabolism during resistance exercise training in healthy volunteers. Methods Following informed consent and screening, 17 healthy, young, exercise-trained males matched for leg strength were allocated to Diclofenac (75mg diclofenac sodium daily, n=9) or Placebo (n=8) groups. Participants performed 5×30 sets of maximal isokinetic (90°/s) knee extensions with the non-dominant leg 3× weekly over 12 weeks. Vastus lateralis biopsies were obtained in the fasted state at baseline and 1, 7, 28, and 84 days of training for histochemical determination of IMCL content and muscle mRNA expression using microfluidic gene cards. IPA identified gene networks altered from baseline. Results There were significant changes in muscle mRNA expression levels associated with the upregulation of muscle lipid metabolism at all time points compared to baseline in Diclofenac. This was not evident in Placebo, where the inhibition of lipid metabolism was predicted by day 84. Mean (±SEM) IMCL content was no different between groups at baseline (7.4±3.8% Placebo vs. 6.9±2.6% Diclofenac), and no time/treatment interactions with resistance exercise training were observed (ηp2=0.07). Conclusion Diclofenac administration had a rapid, robust impact on genes regulating muscle lipid metabolism during 12 weeks of exercise training in humans. However, these responses were not associated with changes in IMCL content and further investigation is warranted.

Hypolipidemic and insulin sensitizing effects of salsalate beyond suppressing inflammation in a prediabetic rat model.

Background and aims: Low-grade chronic inflammation plays an important role in the pathogenesis of metabolic syndrome, type 2 diabetes and their complications. In this study, we investigated the effects of salsalate, a non-steroidal anti-inflammatory drug, on metabolic disturbances in an animal model of prediabetes-a strain of non-obese hereditary hypertriglyceridemic (HHTg) rats. Materials and Methods: Adult male HHTg and Wistar control rats were fed a standard diet without or with salsalate delivering a daily dose of 200mg/kg of body weight for 6weeks. Tissue sensitivity to insulin action was measured ex vivo according to basal and insulin-stimulated 14C-U-glucose incorporation into muscle glycogen or adipose tissue lipids. The concentration of methylglyoxal and glutathione was determined using the HPLC-method. Gene expression was measured by quantitative RT-PCR. Results: Salsalate treatment of HHTg rats when compared to their untreated controls was associated with significant amelioration of inflammation, dyslipidemia and insulin resistance. Specificaly, salsalate treatment was associated with reduced inflammation, oxidative and dicarbonyl stress when inflammatory markers, lipoperoxidation products and methylglyoxal levels were significantly decreased in serum and tissues. In addition, salsalate ameliorated glycaemia and reduced serum lipid concentrations. Insulin sensitivity in visceral adipose tissue and skeletal muscle was significantly increased after salsalate administration. Further, salsalate markedly reduced hepatic lipid accumulation (triglycerides -29% and cholesterol -14%). Hypolipidemic effects of salsalate were associated with differential expression of genes coding for enzymes and transcription factors involved in lipid synthesis (Fas, Hmgcr), oxidation (Pparα) and transport (Ldlr, Abc transporters), as well as changes in gene expression of cytochrome P450 proteins, in particular decreased Cyp7a and increased Cyp4a isoforms. Conclusion: These results demonstrate important anti-inflammatory and anti-oxidative effects of salsalate that were associated with reduced dyslipidemia and insulin resistance in HHTg rats. Hypolipidemic effects of salsalate were associated with differential expression of genes regulating lipid metabolism in the liver. These results suggest potential beneficial use of salsalate in prediabetic patients with NAFLD symptoms.

Histological and transcriptomic analysis of muscular atrophy associated with depleted flesh pigmentation in Atlantic salmon (Salmo salar) exposed to elevated seawater temperatures

Tasmania is experiencing increasing seawater temperatures during the summer period which often leads to thermal stress-induced starvation events in farmed Atlantic salmon, with consequent flesh pigment depletion. Our previous transcriptomic studies found a link between flesh pigmentation and the expression of genes regulating lipid metabolism accompanied by feeding behavior in the hindgut. However, the impact of prolonged exposure to elevated water temperature on muscle structural integrity and molecular mechanisms in muscle underlying pigment variation has not been elucidated to date. In this study, we investigated the effect of prolonged exposure to elevated water temperature on the farmed salmon flesh pigmentation and structural integrity, using muscle histological and transcriptomic analysis. On April 2019, after the end of the summer, two muscle regions of the fish fillet, front dorsal and back central (usually the most and least affected by depletion, respectively), were sampled from fifteen fish (weighing approximately 2 kg and belonging to the same commercial population split in two cages). The fish represented three flesh color intensity groups (n = 5 fish per group) categorized according to general level of pigmentation and presence of banding (i.e. difference in color between the two regions of interest) as follows: high red color-no banding (HN), high red color-banded (HB) and Pale fish. Histological analysis showed a distinction between the flesh color intensity phenotypes in both muscle regions. Muscle fibers in the HB fish were partly degraded, while they were atrophied and smaller in size in Pale fish compared to HN fish. In the Pale fish, interstitial spaces between muscle fibers were also enlarged. Transcriptomic analysis showed that in the front dorsal region of the HN fish, genes encoding collagens, calcium ion binding and metabolic processes were upregulated while genes related to lipid and fatty acid metabolism were downregulated when compared to HB fish. When comparing the back central region of the three phenotypes, actin alpha skeletal muscle and myosin genes were upregulated in the HN and HB fish, while tropomyosin genes were upregulated in the Pale fish. Also, genes encoding heat shock proteins were upregulated in the HN fish, while genes involving lipid metabolism and proteolysis were upregulated in the Pale fish. Starvation, likely caused by thermal stress during prolonged periods of elevated summer water temperatures, negatively affects energy metabolism to different extents, leading to localized or almost complete flesh color depletion in farmed Atlantic salmon. Based on our results, we conclude that thermal stress is responsible not only for flesh discoloration but also for loss of muscle integrity, which likely plays a key role in pigment depletion.

Distinct dynamics of lipid accumulation by porcine cumulus cells during in vitro maturation with follicular fluid of low and high fatty acid contents

Follicular fluid (FF) is a complex biological medium providing a fully balanced microenvironment for the oocyte. The standard medium for in vitro maturation of porcine oocytes contains 10% of FF which due to its unknown and inconstant composition is a source of a significant variation. This study aimed to investigate whether follicular fluids of significantly different fatty acid contents (standardized follicular fluid) supplemented to porcine IVM media affects lipid metabolism of porcine oocytes and cumulus cells. Two categories of FF from cyclic gilts containing high (H) and low (L) FA content was added to IVM medium for oocytes from prepubertal gilts. Altogether, 521 cumulus oocyte-complexes (oocytes and corresponding cumulus cells) were analyzed for mRNA expression of 7 genes regulating lipid metabolism and selected traits of the lipid droplets (LD). The applied FFs of different FA levels exerted distinct effects on oocytes and cumulus cells (CCs). During IVM oocytes tended to utilize the lipids as demonstrated by the reduced LD number and lipid fluorescence, whereas cumulus cells accumulated lipids as indicated by the increase in LD number, the occupied area and fluorescence level. Changes in cumulus cells were independent of the FA content in the follicular fluid which means an efficient lipid accumulation during IVM. Final analysis including the effect of FA level on LD traits in oocytes and corresponding CCs revealed two distinct patterns. COCs matured in FF of high FA content were characterized by elevated dynamics of lipid accumulation in CCs and stable lipid content in oocytes. In the case of FF with low FA content, CCs accumulated lipids at a significantly lower rate whereas lipid level in oocytes was reduced. The alterations observed in the LD parameters were not accompanied by changes in oocyte nuclear maturation and in transcript level of any from the 7 analyzed genes. In conclusion, fatty acid content of the follicular fluid supplemented to porcine IVM medium affects lipid metabolism in cumulus cells of the maturing oocyte and application of a standardized FF may help to improve the quality of porcine oocytes matured in vitro.

313-OR: A Cytoskeleton-Based Mechanism Regulates Lipid Metabolism and Energy Homeostasis in Brown Adipose Tissue

Genetic variants in ANK2, encoding ankyrin-B (AnkB) , increase risk of obesity and type 2 diabetes in humans. We previously concluded that AnkB deficiency in white (WAT) and brown (BAT) adipose tissue (AT) of mice (AT-AnkB KO) led to lipotoxicity, WAT hypertrophy, and insulin resistance associated with age and consumption of a high-fat diet. These metabolic deficits were caused by impairments in glucose transporter GLUT4 endocytosis in WAT due to AnkB deficiency. Additionally, we found that AT-AnkB KO mice had decreased energy expenditure and lipid accumulation in BAT prior to the onset of obesity suggesting a potential role of AnkB in BAT. However, the role of AnkB in BAT and its contribution to metabolic homeostasis through BAT has not been elucidated. We investigated the role of AnkB in mice conditionally lacking AnkB in BAT (BAT-AnkB KO) . Based on histological and transmission electron microscopy analysis, we found that young (4-month-old) BAT-AnkB KO mice have enlarged lipid droplets, lipid accumulation, and decreased mitochondrial content in BAT with no changes in BAT size, body weight, or body composition. Consistent with these findings, primary brown adipocytes from BAT-AnkB KO mice exhibited lipid accumulation suggesting that AnkB may regulate lipid homeostasis in BAT in a cell-autonomous manner. Similar to our previous findings, young BAT-AnkB KO mice also had decreases in oxygen consumption and energy expenditure. These mice also exhibit minimal changes in glucose handling and insulin tolerance at 4-months of age. Proteomic-MS analysis was performed on AnkB associated proteins from BAT which revealed that GLUT4 as well as a number of critical regulators of lipid metabolism form complexes with AnkB in BAT. In combination with this data, we will present our latest findings in gene expression of genes regulating lipid metabolism and mitochondrial function as well as cellular assays in brown adipocytes that may highlight metabolic pathways regulated by AnkB in BAT. Disclosure A.Aguillard: None. J.Arricastres: None. J.Tzeng: None. D.Lorenzo: None. Funding American Diabetes Association (1-19-JDF-081)

Study on the Regulation Mechanism of Lipopolysaccharide on Oxidative Stress and Lipid Metabolism of Bovine Mammary Epithelial Cells

The long-term feeding of a high-concentrate diet (the concentrate ratio is greater than 60 %) leads to mammary gland inflammatory response in ruminants and decreased quality in dairy cows and affects the robust development of the dairy industry. The main reason is closely related to elevated lipopolysaccharide (LPS) in the body. In this experiment, a bovine mammary epithelial cell line (MAC-T) was used as a model, and LPS at different concentrations (0 ng/ml, 1 ng/ml, 10 ng/ml, 100 ng/ml, 1000 ng/ml, 10000 ng/ml) was added to the cells. The cell survival rate, oxidative stress indicators, total lipid droplet area, triglyceride content and key genes regulating lipid metabolism were detected by 3-(4,5)-dimethylthiahiazo(-z-y1)-3,5-di-phenytetrazoliumromide (MTT), assay kit, microscope observation and RT-PCR methods to explore the regulatory mechanism of mammary health and milk fat synthesis. The results showed that compared with those of the control group, the survival rates of cells were significantly decreased after 9 h of stimulation with 1000 ng/ml and 10000 ng/ml LPS (P&lt;0.01). The contents of superoxide dismutase (SOD), catalase (CAT) and total antioxidant capacity (T-AOC) in cells were significantly decreased (P&lt;0.05). Compared with that of the control group, the content of malondialdehyde (MDA) in cells was significantly increased (P&lt;0.05) after stimulation with 10000 ng/ml LPS for 9 h. After 9 h of stimulation with 100 ng/ml, 1000 ng/ml and 10000 ng/ml LPS, the total lipid drop area and triglyceride (TG) content of MAC-T cells were significantly decreased (P&lt;0.05). The expression levels of fatty acid synthesis-related genes Acetyl-CoA carboxylase (ACC) and Stearoyl-CoA desaturase 1 (SCD-1) were significantly decreased after 9 h of stimulation with 100 ng/ml, 1000 ng/ml and 10000 ng/ml LPS (P&lt;0.05), while the expression levels of Fatty Acid synthetase (FAS) were significantly decreased after stimulation with 1000 ng/ml and 10000 ng/ml LPS (P&lt;0.05). TG synthesis by the related gene Diacylglycerol acyltransferase-1 (DGAT1) was significantly lower than that of the control group after stimulation with 1000 ng/ml and 10000 ng/ml LPS for 9 h (P&lt;0.05), and Diacylglycerol acyltransferase-2 (DGAT2) also showed a significant decrease after 10000 ng/ml LPS stimulation (P&lt;0.05). In conclusion, adding different concentrations of LPS to MAC-T cells not only led to a decrease in cell activity, resulting in oxidative damage, but also affected fatty acid and TG synthesis, which may ultimately be closely related to the decrease in milk fat synthesis.

Study on the regulation mechanism of lipopolysaccharide on oxidative stress and lipid metabolism of bovine mammary epithelial cells.

The long-term feeding of a high-concentrate diet (the concentrate ratio is greater than 60 %) leads to mammary gland inflammatory response in ruminants and decreased quality in dairy cows and affects the robust development of the dairy industry. The main reason is closely related to elevated lipopolysaccharide (LPS) in the body. In this experiment, a bovine mammary epithelial cell line (MAC-T) was used as a model, and LPS at different concentrations (0 ng/ml, 1 ng/ml, 10 ng/ml, 100 ng/ml, 1000 ng/ml, 10000 ng/ml) was added to the cells. The cell survival rate, oxidative stress indicators, total lipid droplet area, triglyceride content and key genes regulating lipid metabolism were detected by 3-(4,5)-dimethylthiahiazo(-z-y1)-3,5-di-phenytetrazoliumromide (MTT), assay kit, microscope observation and RT-PCR methods to explore the regulatory mechanism of mammary health and milk fat synthesis. The results showed that compared with those of the control group, the survival rates of cells were significantly decreased after 9 h of stimulation with 1000 ng/ml and 10000 ng/ml LPS (P<0.01). The contents of superoxide dismutase (SOD), catalase (CAT) and total antioxidant capacity (T-AOC) in cells were significantly decreased (P<0.05). Compared with that of the control group, the content of malondialdehyde (MDA) in cells was significantly increased (P<0.05) after stimulation with 10000 ng/ml LPS for 9 h. After 9 h of stimulation with 100 ng/ml, 1000 ng/ml and 10000 ng/ml LPS, the total lipid drop area and triglyceride (TG) content of MAC-T cells were significantly decreased (P<0.05). The expression levels of fatty acid synthesis-related genes Acetyl-CoA carboxylase (ACC) and Stearoyl-CoA desaturase 1 (SCD-1) were significantly decreased after 9 h of stimulation with 100 ng/ml, 1000 ng/ml and 10000 ng/ml LPS (P<0.05), while the expression levels of Fatty Acid synthetase (FAS) were significantly decreased after stimulation with 1000 ng/ml and 10000 ng/ml LPS (P<0.05). TG synthesis by the related gene Diacylglycerol acyltransferase-1 (DGAT1) was significantly lower than that of the control group after stimulation with 1000 ng/ml and 10000 ng/ml LPS for 9 h (P<0.05), and Diacylglycerol acyltransferase-2 (DGAT2) also showed a significant decrease after 10000 ng/ml LPS stimulation (P<0.05). In conclusion, adding different concentrations of LPS to MAC-T cells not only led to a decrease in cell activity, resulting in oxidative damage, but also affected fatty acid and TG synthesis, which may ultimately be closely related to the decrease in milk fat synthesis.

N-myc downstream regulated family member 1 (NDRG1) is enriched in myelinating oligodendrocytes and impacts myelin degradation in response to demyelination.

The N-myc downstream regulated gene family member 1 (NDRG1) is a gene whose mutation results in peripheral neuropathy with central manifestations. While most of previous studies characterized NDRG1 role in Schwann cells, the detection of central nervous system symptoms and the identification of NDRG1 as a gene silenced in the white matter of multiple sclerosis brains raise the question regarding its role in oligodendrocytes. Here, we show that NDRG1 is enriched in oligodendrocytes and myelin preparations, and we characterize its expression using a novel reporter mouse (TgNdrg1-EGFP). We report NDRG1 expression during developmental myelination and during remyelination after cuprizone-induced demyelination of the adult corpus callosum. The transcriptome of Ndrg1-EGFP+ cells further supports the identification of late myelinating oligodendrocytes, characterized by expression of genes regulating lipid metabolism and bioenergetics. We also generate a lineage specific conditional knockout (Olig1cre/+ ;Ndrg1fl/fl ) line to study its function. Null mice develop normally, and despite similar numbers of progenitor cells as wild type, they have fewer mature oligodendrocytes and lower levels of myelin proteins than controls, thereby suggesting NDRG1 as important for the maintenance of late myelinating oligodendrocytes. In addition, when control and Ndrg1 null mice are subject to cuprizone-induced demyelination, we observe a higher degree of demyelination in the mutants. Together these data identify NDRG1 as an important molecule for adult myelinating oligodendrocytes, whose decreased levels in the normal appearing white matter of human MS brains may result in greater susceptibility of myelin to damage.

Global investigation of estrogen-responsive genes regulating lipid metabolism in the liver of laying hens

BackgroundEstrogen plays an essential role in female development and reproductive function. In chickens, estrogen is critical for lipid metabolism in the liver. The regulatory molecular network of estrogen in chicken liver is poorly understood. To identify estrogen-responsive genes and estrogen functional sites on a genome-wide scale, we determined expression profiles of mRNAs, lncRNAs, and miRNAs in estrogen-treated ((17β-estradiol)) and control chicken livers using RNA-Sequencing (RNA-Seq) and studied the estrogen receptor α binding sites by ChIP-Sequencing (ChIP-Seq).ResultsWe identified a total of 990 estrogen-responsive genes, including 962 protein-coding genes, 11 miRNAs, and 17 lncRNAs. Functional enrichment analyses showed that the estrogen-responsive genes were highly enriched in lipid metabolism and biological processes. Integrated analysis of the data of RNA-Seq and ChIP-Seq, identified 191 genes directly targeted by estrogen, including 185 protein-coding genes, 4 miRNAs, and 2 lncRNAs. In vivo and in vitro experiments showed that estrogen decreased the mRNA expression of PPARGC1B, which had been reported to be linked with lipid metabolism, by directly increasing the expression of miR-144-3p.ConclusionsThese results increase our understanding of the functional network of estrogen in chicken liver and also reveal aspects of the molecular mechanism of estrogen-related lipid metabolism.

Hepatic Steatosis and Ectopic Fat Are Associated With Differences in Subcutaneous Adipose Tissue Gene Expression in People With HIV.

Persons with human immunodeficiency virus (PWH) have subcutaneous adipose tissue (SAT) dysfunction related to antiretroviral therapy and direct viral effects, which may contribute to a higher risk of nonalcoholic fatty liver disease compared with human immunodeficiency virus–negative individuals. We assessed relationships between SAT expression of major adipocyte regulatory and lipid storage genes with hepatic and other ectopic lipid deposits in PWH. We enrolled 97 PWH on long‐term antiretroviral therapy with suppressed plasma viremia and performed computed tomography measurements of liver attenuation, a measure of hepatic steatosis, skeletal muscle (SM) attenuation, and the volume of abdominal subcutaneous, visceral, and pericardial adipose tissue. Whole SAT gene expression was measured using the Nanostring platform, and relationships with computed tomography imaging and fasting lipids were assessed using multivariable linear regression and network mapping. The cohort had a mean age of 47 years, body mass index of 33.4 kg/m2, and CD4 count of 492 cells/mm3. Lower liver attenuation, a marker of greater steatosis, was associated with differences in SAT gene expression, including lower lipoprotein lipase and acyl‐CoA dehydrogenase, and higher phospholipid transfer protein. Lower liver attenuation clustered with lower visceral adipose tissue (VAT) attenuation and greater VAT volume, pericardial fat volume and triglycerides, but no relationship was observed between liver attenuation and SAT volume, SM attenuation, or low‐density lipoprotein. Conclusion: Liver attenuation was associated with altered SAT expression of genes regulating lipid metabolism and storage, suggesting that SAT dysfunction may contribute to nonalcoholic fatty liver disease in PWH. SAT gene‐expression relationships were similar for VAT volume and attenuation, but not SM, indicating that ectopic lipid deposition may involve multiple pathways.

Effects of prolonged photoperiod on growth performance, serum lipids and meat quality of Jinjiang cattle in winter

ObjectiveThis study was conducted to investigate the potential effects of prolonged photoperiod on the serum lipids, carcass traits, and meat quality of Jinjiang cattle during winter.MethodsThirty-four Jinjiang bulls aged between 14 and 16 months were randomly assigned to two groups that were alternatively subjected to either natural daylight +4 h supplemental light (long photoperiod, LP) or natural daylight (natural photoperiod, NP) for 96 days. The potential effects on the levels of serum lipids, carcass traits, meat quality, and genes regulating lipid metabolism in the intramuscular fat (IMF) of the cattle were evaluated.ResultsJinjiang cattle kept under LP showed significant increase in both dry matter intake and backfat thickness. the serum glucose and the plasma leptin levels were significantly reduced, while that of melatonin and insulin were observed to be increased. The crude fat contents of biceps femoris muscle and longissimus dorsi muscle were higher in LP than in NP group. In longissimus dorsi muscle, the proportions of C17:0 and C18:0 were significantly higher but that of the C16:1 was found to be significantly lower in LP group. The relative mRNA expressions in IMF of longissimus dorsi muscle, the lipid synthesis genes (proliferator-activated receptor gamma, fatty acid-binding protein) and the fatty acid synthesis genes (acetyl-coa carboxylase, fatty acid synthetase, 1-acylglycerol-3-phosphate acyltransferase) were significantly up-regulated in LP group (p<0.05); whereas the hormone-sensitive lipase and stearoyl-CoA desaturase 1 were significantly down-regulated in LP than in NP group.ConclusionProlonged photoperiod significantly altered the growth performance, hormonal levels, gene expression and fat deposition in Jinjiang cattle. It suggested that the LP improved the fat deposition by regulating the levels of different hormones and genes related to lipid metabolism, thereby improving the fattening of Jinjiang cattle during winter.

Inhibiting diacylglycerol acyltransferase-1 reduces lipid biosynthesis in bovine blastocysts produced in vitro

Diacylglycerol acyltransferase-1 (DGAT1) is one of the DGAT enzymes that catalyzes the final step in the synthesis of triacylglycerol, which is a major component of the lipid droplets in embryos. Intracellular lipids accumulated in embryos produced in vitro have been associated with reduced cryotolerance and quality. The objective of the present study was to investigate the influence of DGAT1 inhibition on embryo development, quality, and post-vitrification survival, in addition to expression profiles of selected lipid metabolism-regulating and oxidative stress genes. Bovine cumulus-oocyte complexes were matured and fertilized in vitro and were cultured in synthetic oviduct fluid (SOF) supplemented with 5% fetal calf serum (FCS) alone (Control) or with 1, 5, 10 or 50 μM DGAT1 inhibitor (A922500®; D1, D5, D10, and D50, respectively) or 0.1% dimethyl sulfoxide (CDMSO: vehicle for DGAT1 inhibitor dilution) from 54 h post-insemination until Day 8 post insemination. No differences were found in blastocyst yield on days 7 and 8 in Control, CDMSO, D10, and D50 groups. Embryos cultured with 10 or 50 μM DGAT1 inhibitor had greater mitochondrial activity (P < 0.01), and increased number of cells (P < 0.05), while the cytoplasmic lipid content was reduced (P < 0.01), the latter associated with altered expression profiles of selected genes regulating lipid metabolism or genes related with oxidative stress (transcript abundance increased for SLC2A1 and SLC2A5 and decreased for DGAT1 and GPX1). Importantly, the survival rate of blastocysts produced with 10 μM DGAT1 was higher than that of Control, CDMSO and D50 groups at 72 h after vitrification and warming (73.8 vs 57.1, 55.9 and 56.1%, respectively, P < 0.001). In conclusion, inhibition of DGAT1 synthesis in bovine embryos produced in vitro abrogates the negative effect of FCS by decreasing their lipid content, increasing mitochondria activity and improving embryo cryotolerance, as well as favoring the expression of lipid metabolism regulating and oxidative stress-related transcripts.

Loss of Evolutionarily Acquired Functions of Atp1b4 leads to Increase Energy Expenditure and Protection Against Diet‐Induced Obesity of Adult Mice

Co‐option of vertebrate orthologous ATP1B4 genes in placental mammals radically changed properties of the encoded BetaM‐proteins. These proteins in lower vertebrates are authentic Na, K‐ATPase β‐subunits which in complex with a‐subunits function as ion pumps in the plasma membrane.In placental mammals BetaM proteins gained entirely different properties through structural changes of N‐terminal domains. As a result of these evolutionary alterations, eutherian BetaM completely lost its ancestral role and became the only currently known skeletal and atrial cardiac muscle‐specific protein of the inner nuclear membrane, which is expressed at highest level during perinatal development and is implicated in gene expression regulation.Loss of BetaM the Atp1b4 knockout mouse model results in significantly lower body size and weight, growth retardation and high mortality of neonates. Transcriptome analysis by mRNA sequencing of skeletal muscle from neonatal wild type and knockout littermates revealed broad changes in expression of genes regulating lipid metabolism. These results imply that BetaM plays an essential role during a critical period of perinatal and neonatal development of placental mammals and its damage or malfunction can cause birth and growth defects in humans.Most importantly, Atp1b4 disruption exhibits a somewhat unexpected and profound beneficial effect of on metabolic parameters in adult male mice. BetaM deficient (Atp1b4‐/Y) mice have significantly lower body weight and remarkably low adiposity. They exhibit lower fasting blood glucose, enhanced insulin sensitivity and improved glucose tolerance and are resistant to high‐fat diet‐induced obesity as compared to their wild type littermates. Knockout mice display higher heat production associated with increased food intake, elevated oxygen consumption especially in darkness and higher locomotor activity. Lower respiratory exchange ratio of knockout mice indicates that fat from high‐fat diet is metabolized rather than deposited as storage. These robust changes in mouse metabolic parameters induced by Atp1b4 disruption clearly demonstrate that eutherian BetaM plays the important role in development of pathways regulating metabolism of adult mice.Finally, ablation of the evolutionarily acquired functions of Atp1b4 gene in mice is in fact a simulation of the alternative pathway of mammalian evolution.Support or Funding InformationThis work was supported by College of Medicine and Life Sciences, Center for Diabetes and Endocrine Research and Department of Physiology &amp; Pharmacology, University of Toledo