Lipid Droplet Area Research Articles

Hepatic galectin-3 is associated with lipid droplet area in non-alcoholic steatohepatitis in a new swine model

Non-alcoholic fatty liver disease (NAFLD) is currently a growing epidemic disease that can lead to cirrhosis and hepatic cancer when it evolves into non-alcoholic steatohepatitis (NASH), a gap not well understood. To characterize this disease, pigs, considered to be one of the most similar to human experimental animal models, were used. To date, all swine-based settings have been carried out using rare predisposed breeds or long-term experiments. Herein, we fully describe a new experimental swine model for initial and reversible NASH using cross-bred animals fed on a high saturated fat, fructose, cholesterol, cholate, choline and methionine-deficient diet. To gain insight into the hepatic transcriptome that undergoes steatosis and steatohepatitis, we used RNA sequencing. This process significantly up-regulated 976 and down-regulated 209 genes mainly involved in cellular processes. Gene expression changes of 22 selected transcripts were verified by RT-qPCR. Lipid droplet area was positively associated with CD68, GPNMB, LGALS3, SLC51B and SPP1, and negatively with SQLE expressions. When these genes were tested in a second experiment of NASH reversion, LGALS3, SLC51B and SPP1 significantly decreased their expression. However, only LGALS3 was associated with lipid droplet areas. Our results suggest a role for LGALS3 in the transition of NAFLD to NASH.

Intrauterine growth restriction elevates circulating acylcarnitines and suppresses fatty acid metabolism genes in the fetal sheep heart.

At birth, the mammalian myocardium switches from using carbohydrates as the primary energy substrate to free fatty acids as the primary fuel. Thus, a compromised switch could jeopardize normal heart function in the neonate. Placental embolization in sheep is a reliable model of intrauterine growth restriction (IUGR). It leads to suppression of both proliferation and terminal differentiation of cardiomyocytes. We hypothesized that the expression of genes regulating cardiac fatty acid metabolism would be similarly suppressed in IUGR, leading to compromised processing of lipids. Following 10 days of umbilicoplacental embolization in fetal sheep, IUGR fetuses had elevated circulating long-chain fatty acylcarnitines compared with controls (C14: CTRL 0.012 ± 0.005nmol/ml vs. IUGR 0.018 ± 0.005nmol/ml, P < 0.05; C18: CTRL 0.027 ± 0.009nmol/mol vs. IUGR 0.043 ± 0.024nmol/mol, P < 0.05, n = 12 control, n = 12 IUGR) indicative of impaired fatty acid metabolism. Uptake studies using fluorescently tagged BODIPY-C12-saturated free fatty acid in live, isolated cardiomyocytes showed lipid droplet area and number were not different between control and IUGR cells. mRNA levels of sarcolemmal fatty acid transporters (CD36, FATP6), acylation enzymes (ACSL1, ACSL3), mitochondrial transporter (CPT1), β-oxidation enzymes (LCAD, HADH, ACAT1), tricarboxylic acid cycle enzyme (IDH), esterification enzymes (PAP, DGAT) and regulator of the lipid droplet formation (BSCL2) gene were all suppressed in IUGR myocardium (P < 0.05). However, protein levels for these regulatory genes were not different between groups. This discordance between mRNA and protein levels in the stressed myocardium suggests an adaptive protection of key myocardial enzymes under conditions of placental insufficiency. KEY POINTS: The fetal heart relies on carbohydrates in utero and must be prepared to metabolize fatty acids after birth but the effects of compromised fetal growth on the maturation of this metabolic system are unknown. Plasma fatty acylcarnitines are elevated in intrauterine growth-restricted (IUGR) fetuses compared with control fetuses, indicative of impaired fatty acid metabolism in fetal organs. Fatty acid uptake and storage are not different in IUGR cardiomyocytes compared with controls. mRNA levels of genes regulating fatty acid transporter and metabolic enzymes are suppressed in the IUGR myocardium compared with controls, while protein levels remain unchanged. Mismatches in gene and protein expression, and increased circulating fatty acylcarnitines may have long-term implications for offspring heart metabolism and adult health in IUGR individuals. This requires further investigation.

Substituting dietary fishmeal with soybean meal isolate influences hepatic lipid metabolism and gut microbiota in spotted seabass (Lateolabrax maculatus)

This study was conducted to investigate the effects of partial substitution of dietary fishmeal (FM) by soy protein isolate (SPI) on lipid metabolism and gut microbiota of spotted seabass. A diet containing 30% FM formed the basal diet (FM), and two SPI diets were formulated in which 25% (SPI25) and 50% (SPI50) of FM were replaced by SPI. Each diet was fed to triplicates of fish for 56 days. The results showed that replacing dietary FM with SPI reduced triglyceride and cholesterol contents in the liver and serum, and the hepatic lipid droplets area was also decreased by dietary SPI inclusion. Furthermore, replacement of dietary FM with SPI markedly down-regulated the mRNA expression of genes involved in lipogenesis (srebpc-1c, fas, acc1, hmgcr, pparγ and chrebp) and lipolysis (atgl, hsl, pparα, and cpt1). Moreover, high-throughput sequencing analyses of gut microbiota revealed that dietary SPI inclusion dramatically decreased the Firmicutes/Bacteroidetes ratio. Overall, this study indicated that replacing 25-50% of dietary FM with SPI could reduce lipid accumulation in serum and liver of spotted seabass, which was associated with the suppressed hepatic lipogenesis and the remodeled gut microbiota.

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.

Fractions of Shen-Sui-Tong-Zhi Formula Enhance Osteogenesis Via Activation of β-Catenin Signaling in Growth Plate Chondrocytes.

Background: Shen-sui-tong-zhi formula (SSTZF) has been used to treat osteoporosis for decades and shows excellent clinical efficacy. This article aims to explore the optimal anti-osteoporotic ingredient and its precise mechanisms in mice models. Methods: In this study, we first screened the optimal anti-osteoporosis fraction of SSTZF extract in vivo, and then further explored the mechanism of its effects both in vivo and in vitro. Ten-week-old female C57BL/6J mice were administrated with each fraction of SSTZF. At 10 weeks after ovariectomy (OVX), femurs were collected for tissue analyses, including histology, micro-CT, biomechanical tests, and immunohistochemistry for ALP, FABP4, and β-catenin. Additionally, we also evaluated the mRNA expression level of ALP and FABP4 and the protein expression level of β-catenin after being treated with SSTZF extract in C3H10T1/2 cells. Moreover, we investigated the anti-osteoporosis effect of SSTZF extract on mice with β-catenin conditional knockout in growth plate chondrocytes (β-catenin Gli1ER mice) through μCT, histology, and immunohistochemistry analyzes. Results: At 10 weeks after treatment, osteoporosis-like phenotype were significantly ameliorated in SSTZF n-butanol extract (SSTZF-NB) group mice, as indicated by increased trabecular bone area and ALP content, and decreased lipid droplet area and FABP4 content. No such improvements were observed after being treated with other extracts, demonstrating that SSTZF-NB is the optimal anti-osteoporosis fraction. Additionally, the elevated β-catenin was revealed in both OVX mice and C3H10T1/2 cells with SSTZF-NB administered. Furthermore, a significant osteoporosis-like phenotype was observed in β-catenin Gli1ER mice as expected. However, SSTZF-NB failed to rescue the deterioration in β-catenin Gli1ER mice, no significant re-upregulated ALP and downregulated FABP4 were observed after being treated with SSTZF-NB, demonstrating that SSTZF-NB prevents bone loss mainly via β-catenin signaling. Conclusion: SSTZF-NB enhances osteogenesis mainly via activation of β-catenin signaling in growth plate chondrocytes. SSTZF-NB is the optimal anti-osteoporosis fraction of SSTZF and it can be considered a salutary alternative therapeutic option for osteoporosis.

Dietary supplementation of exogenous probiotics reduces excessive liver lipid deposition in Chinese perch ( Siniperca chuatsi )

This study aimed to screen the exogenous probiotics that can be used to reduce excessive liver lipid deposition in Chinese perch (Siniperca chuatsi). Chinese perch were, respectively, fed with basal diet (CK) supplemented with Bacillus subtilis BS1 (B) and Lactobacillus plantarum LP1 (L) for 8 weeks. B group and L group exhibited significantly lower crude lipid content in liver than CK group. The relative area of lipid droplets of B group and L group were significantly reduced compared to CK group. B group and L group showed higher levels of total triglyceride and cholesterol than CK group in plasma. The levels of acetate in gut chyme and plasma of B group and L group were significantly higher than those in CK group. The transcript levels of ampk, pparα, cpt1, cs, hl and apoe in B group and L group were significantly higher than those in CK group. The present study indicated that the two exogenous probiotics (Bacillus subtilis BS1 and Lactobacillus plantarum LP1) can be used in aquaculture to reduce excessive liver lipid deposition in Chinese Perch.

Lipid droplet screen in human hepatocytes identifies TRRAP as a regulator of cellular triglyceride metabolism.

Hepatocytes store triglycerides (TGs) in the form of lipid droplets (LDs), which are increased in hepatosteatosis. The regulation of hepatic LDs is poorly understood and new therapies to reduce hepatosteatosis are needed. We performed a siRNA kinase and phosphatase screen in HuH‐7 cells using high‐content automated imaging of LDs. Changes in accumulated lipids were quantified with developed pipeline that measures intensity, area, and number of LDs. Selected “hits,” which reduced lipid accumulation, were further validated with other lipid and expression assays. Among several siRNAs that resulted in significantly reduced LDs, one was targeted to the nuclear adapter protein, transformation/transcription domain‐associated protein (TRRAP). Knockdown of TRRAP reduced triglyceride accumulation in HuH‐7 hepatocytes, in part by reducing C/EBPα‐mediated de novo synthesis of TGs. These findings implicate TRRAP as a novel regulator of hepatic TG metabolism and nominate it as a potential drug target for hepatosteatosis.

Short Time-Series Expression Transcriptome Data Reveal the Gene Expression Patterns of Dairy Cow Mammary Gland as Milk Yield Decreased Process.

The existing research on dairy cow mammary gland genes is extensive, but there have been few reports about dynamic changes in dairy cow mammary gland genes as milk yield decrease. For the first time, transcriptome analysis based on short time-series expression miner (STEM) and histological observations were performed using the Holstein dairy cow mammary gland to explore gene expression patterns in this process of decrease (at peak, mid-, and late lactation). Histological observations suggested that the number of mammary acinous cells at peak/mid-lactation was significantly higher than that at mid-/late lactation, and the lipid droplets area secreted by dairy cows was almost unaltered across the three stages of lactation (p > 0.05). Totals of 882 and 1439 genes were differentially expressed at mid- and late lactation, respectively, compared to peak lactation. Function analysis showed that differentially expressed genes (DEGs) were mainly related to apoptosis and energy metabolism (fold change ≥ 2 or fold change ≤ 0.5, p-value ≤ 0.05). Transcriptome analysis based on STEM identified 16 profiles of differential gene expression patterns, including 5 significant profiles (false discovery rate, FDR ≤ 0.05). Function analysis revealed DEGs involved in milk fat synthesis were downregulated in Profile 0 and DEGs in Profile 12 associated with protein synthesis. These findings provide a foundation for future studies on the molecular mechanisms underlying mammary gland development in dairy cows.

Engineering yeast subcellular compartments for increased production of the lipophilic natural products ginsenosides

Eukaryotic yeasts have a variety of subcellular compartments and are ideal platform strains for the construction of complex heterologous natural product biosynthesis pathways. Improving the synthesis efficiency of microbial cell factories through the utilization and modification of subcellular compartments by synthetic biology has good application prospects. Here, we used the yeast PLN1 protein to target the normally endoplasmic reticulum (ER)-localized cytochrome P450 enzyme protopanaxadiol (PPD) synthase (PPDS) to lipid droplets (LDs), which are the storage organelles of the PPDS substrate dammarenediol-II (DD). The efficiency of converting DD to PPD was significantly increased by 394%, and the conversion rate of DD increased from 17.4% to 86.0%. Furthermore, increasing the volume of LDs can significantly enhance the production of DD and its derivatives, but the change in the ratio of the volume and surface area of LDs decreased the conversion efficiency of DD to PPD. Additionally, the biosynthetic pathways of the PPD-type saponin ginsenoside compound K (CK) was reconstituted in a PPD-producing chassis strain, and CK production reached 21.8 mg/L/OD, 4.4-fold higher compared to the native ER-expression strategy. Next, we enhanced the expression of the Pn3-29 gene module to further reduce the accumulation of PPD and increase the production of CK to 41.3 mg/L/OD. Finally, the CK titer of the resulting strain reached 5 g/L in 5 L fed-batch fermentations. This study provides a new strategy for engineering yeast to produce complex natural products.

Inhibition of Elongation Factor 1A1 Activity Decreases Lipid Droplet Accumulation

Non-alcoholic fatty liver disease (NAFLD) is characterized by hepatocyte lipid accumulation, which can cause hepatocyte injury through lipotoxicity. Eukaryotic elongation factor 1A1 (EEF1A1), which is a component of the protein synthetic machinery and regulates actin cytoskeleton turnover, is induced in human hepatocyte-like HepG2 cells undergoing lipotoxicity, in association with ER stress. Moreover, EEF1A1 has been identified in the lipid droplet (LD) proteome in various cell and tissue types, suggesting that it may have a role in LD biology. Partial inhibition of EEF1A1 peptide elongation activity with the marine compound didemnin B (DB) decreases lipotoxic HepG2 cell death. However, the effects of EEF1A1 inhibition on cellular lipid accumulation are unclear. Based on the potential association of EEF1A1 with LDs, and its apparent roles in responding to ER stress and in regulating cytoskeleton dynamics, we hypothesized that inhibition of EEF1A1 with DB would alter hepatocyte LD accumulation. Male 129S6 mice were fed a western diet for 26 weeks to induce NAFLD, followed by intervention with DB (50 μg/kg, i.p.) once every 3 days for 14 days. Treatment with DB decreased liver lipid accumulation, as determined by biochemical and histological analyses, and upregulated expression of genes involved in fatty acid oxidation (Cpt1a, Fgf21). Assessments of LD size in mouse liver revealed a significant decrease in median size upon treatment with DB, suggesting that DB promotes the formation of smaller LDs. To explore whether this effect was conserved in human hepatocyte-like cells, HepG2 cells were treated for 6 h with DB (80 nM) under lipotoxic conditions (1 mM palmitate plus oleate) and LDs were visualized by confocal microscopy. Cells exposed to lipotoxic conditions exhibited increased LD area, and treatment with DB appeared to decrease the formation of large LDs (-63%, p=0.11). This occurred alongside upregulation of CPT1A mRNA, which was consistent with the upregulation of genes involved in fatty acid oxidation observed in mouse liver. Finally, a Chinese hamster ovary cell line that harbors a mutation leading to reduced EEF1A1 expression accumulated less triglyceride under high fatty acid conditions compared to wild-type cells. Together, these findings suggest that that disruption of EEF1A1 activity may diminish LD accumulation and channel excess fatty acids toward oxidation, which could have implications for the treatment of NAFLD.

Berberine regulates lipid metabolism via miR-192 in porcine oocytes matured in vitro.

BackgroundThe berberine (Ber) is an isoquinoline alkaloid compound extracted from Rhizoma coptidis and has the effect that reduces adipose. MicroRNA‐192 (miR‐192) is related to fat metabolism. However, the relevant mechanism of berberine on lipid metabolism during in vitro maturation (IVM) of porcine oocytes remains unclear.ObjectivesIn this study, we investigated the molecular mechanism by which berberine promotes the IVM and lipid metabolism of porcine oocytes via miR‐192.MethodsBer was added to IVM medium of porcine oocytes. MiR‐192 agomir, miR‐192 antagomir and negative control fragment were microinjected into the cytoplasm of oocytes without Ber. Rates of oocyte IVM and embryonic development in each group were observed. The content of lipid droplets in IVM oocytes in each group was analyzed by Nile red staining. Expression levels of miR‐192 and FABP3, SREBF1 and PPARG, were detected by qPCR and western blotting. The target genes of miR‐192 were determined by luciferase reporter assays.Results and ConclusionsWe found that Ber significantly increased the rate of oocytes IVM and blastocyst development, and decreased the area and numbers of lipid droplets in IVM oocytes. Ber significantly increased the expression of miR‐192 in IVM oocytes, and significantly decreased the expression of SREBF1 and PPARG, which were target genes of miR‐192. This study indicates that Ber promotes lipid metabolism in porcine oocytes by activating the expression of miR‐192 and down‐regulating SREBF1 and PPARG, thus, improving IVM of porcine oocytes.

Dietary fucoidan extracted from macroalgae Saccharina japonica alleviate the hepatic lipid accumulation of black seabream (Acanthopagrus schlegelii).

The use of an artificial diet often leads to the increase of risk factors for the development of liver diseases, such as hepatic lipid accumulation (HLA) in commercially cultured fish species. Our previous study showed that dietary Saccharina japonica could effectively alleviate HLA in black seabream (Acanthopagrus schlegelii), which may be linked predominantly to S. japonica fucoidan. Thus, a 56d nutritional trial was designed to investigate the effects of dietary fucoidan (CTRL, 0 g kg-1; ASJ1, 0.75 g kg-1; ASJ2, 3.00 g kg-1) on growth performance, fillets nutritional values, and HLA of black seabream. Results showed that dietary fucoidan significantly improved the growth and the contents of n-3 polyunsaturated fatty acids (n-3PUFA) in fillets of black seabream. Moreover, dietary fucoidan improved HLA-related parameters, including reducing serum and liver lipid contents and the activity of aminotransferase. Meanwhile, histological analysis showed that dietary fucoidan reduced the area of hepatic lipid droplets in black seabream (P < 0.05). In addition, the transcriptomic analysis of differentially expressed gene (DEG) showed that all DEG in fatty acid metabolism, primary bile acid biosynthesis, and fatty acid biosynthesis were down-regulated, and all DEG in the regulation of autophagy were up-regulated in the ASJ1 group compared with CTRL group. Moreover, the metabolomic analysis of differentially expressed metabolite (DEM) found that lipid metabolism was the main type of KEGG pathway altered by fucoidan supplementation. Furthermore, the combined transcriptomic and metabolomic analysis found that dietary fucoidan mainly modified the lipid metabolic pathway of primary bile acid biosynthesis, glycerophospholipid metabolism, and arachidonic acid metabolism in the liver. In general, dietary fucoidan effectively alleviated HLA of black seabream, and the underlying mechanism may be ascribed to promoting the autophagy and inhibiting the synthesis of lipids and bile acids.

Coordinated control of adiposity and growth by anti-anabolic kinase ERK7.

Energy storage and growth are coordinated in response to nutrient status of animals. How nutrient‐regulated signaling pathways control these processes in vivo remains insufficiently understood. Here, we establish an atypical MAP kinase, ERK7, as an inhibitor of adiposity and growth in Drosophila. ERK7 mutant larvae display elevated triacylglycerol (TAG) stores and accelerated growth rate, while overexpressed ERK7 is sufficient to inhibit lipid storage and growth. ERK7 expression is elevated upon fasting and ERK7 mutant larvae display impaired survival during nutrient deprivation. ERK7 acts in the fat body, the insect counterpart of liver and adipose tissue, where it controls the subcellular localization of chromatin‐binding protein PWP1, a growth‐promoting downstream effector of mTOR. PWP1 maintains the expression of sugarbabe, encoding a lipogenic Gli‐similar family transcription factor. Both PWP1 and Sugarbabe are necessary for the increased growth and adiposity phenotypes of ERK7 loss‐of‐function animals. In conclusion, ERK7 is an anti‐anabolic kinase that inhibits lipid storage and growth while promoting survival on fasting conditions.

Lipid-Lowering Effects of Lotus Leaf Alcoholic Extract on Serum, Hepatopancreas, and Muscle of Juvenile Grass Carp via Gene Expression.

Compared with wild grass carp (Ctenopharyngodon idellus), intensively cultured fish displayed disordered lipid metabolism, showing excess lipid deposition in the hepatopancreas and muscle. Lotus leaf prevents fat accumulation in humans and may have similar effects on fish. This study explored the regulatory mechanisms by which the dietary addition of an alcoholic extract of lotus leaf (AELL) reduced lipid deposition in the hepatopancreas and muscle of juvenile grass carp. The fish (average initial weight: 34.00 ± 0.40 g) were fed four experimental diets containing different AELL levels (0, 0.07, 0.14, and 0.21%) for 8 weeks. Serum components, lipid droplet size, triacylglycerol (TAG) content, enzymatic activities, and mRNA levels of genes related to lipid metabolism in the hepatopancreas and muscle were analyzed. The results show that dietary AELL supplementation significantly reduced the TAG content and lipid droplet area in the histological sections as well as the fatty acid synthase (FAS) activity in both the hepatopancreas and muscle but enhanced the activities of lipoprotein lipase (LPL) and carnitine palmitoyltransferase I (CPT1) in both tissues. In addition, dietary AELL supplementation decreased the mRNA expression of genes involved in fatty acid uptake (cd36, fatp1/fatp4/fatp6, fabp10/fabp11, acsl1/acsl4) and de novo lipid synthesis (pgd, g6pd, and fasn) as well as the transcription factors pparg and srebf1 in the hepatopancreas and muscle but increased the mRNA levels of genes relating to lipid catabolism (cpt1a, lipe, pnpla2, lpl), lipid transportation (apob), and the transcription factor ppara in both tissues. In conclusion, dietary AELL supplementation reduced lipid accumulation in the hepatopancreas and muscle by affecting the gene expression of proteins with known effects on lipid metabolism in juvenile grass carp.

Optimal exercise intensity and volume to impact rats with Traditional Chinese Medicine phlegm-dampness constitution

ObjectiveWe aim to investigate the effects of different exercise intensities and volumes on Phlegm-dampness constitution (PDC). MethodsThe rats were fed with high-fat food and lived in 75%–85% humidity for 6 weeks to establish the model of PDC. Then PDC rats were screened and intervened by varying exercise intensities for 8 weeks. Weight, constitution scores, blood and liver tissues were collected to detect the concentration of serum total cholesterol (Tch), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), homocysteine (Hcy), blood glucose (GLU), alanine transaminase (ALT) and percentage of lipid droplet area in liver tissue (PLDA). ResultsThe weight, Tch, TG, HDL-C, LDL-C, Hcy, GLU, and ALT of rats in moderate-intensity exercise group returned to normal. The rats with high-intensity or low-intensity exercise did not recover as well as moderate-intensity. ConclusionDifferent exercise intensities and volumes have different effects on PDC, moderate-intensity exercise over an 8-week intervention is most appropriate.

Cobalt Chloride Induces Macrophage Foam Cell Formation: A Chemical Hypoxia Model for Anti-Atherosclerotic Drug Screening.

Macrophages would engulf circulating oxidized (ox)- low-density lipoprotein and form lipid droplet-laden foam cells. Macrophage foam cells are considered an important therapeutic target of atherosclerosis. The aim of the study was to investigate a hypoxic foam cell model for anti-atherosclerotic drug screening using the chemical hypoxia-mimicking agent cobalt chloride (CoCl2). The oil red O stating results showed that treatment with CoCl2 could induce lipid accumulation and lead to cell transformation to spindle-shaped and lipid-rich foam cells in RAW 264.7 macrophages. Incubation with 150 μM CoCl2 for 24 h significantly increased the area of intracellular lipid droplets in macrophages, compared with the control group. Our findings indicate that CoCl2-triggered macrophage foam cells should be a potential in vitro hypoxia model for atherosclerosis drug discovery.

PTEN Lipid Phosphatase Activity Enhances Dengue Virus Production through Akt/FoxO1/Maf1 Signaling

Dengue virus (DENV) is an arthropod-borne viral pathogen and a global health burden. Knowledge of the DENV-host interactions that mediate virus pathogenicity remains limited. Host lipid metabolism is hijacked by DENV for virus replication in which lipid droplets (LDs) play a key role during the virus lifecycle. In this study, we reveal a novel role for phosphatase and tensin homolog deleted on chromosome 10 (PTEN) in LDs-mediated DENV infection. We demonstrate that PTEN expression is downregulated upon DENV infection through post-transcriptional regulation and, in turn, PTEN overexpression enhances DENV replication. PTEN lipid phosphatase activity was found to decrease cellular LDs area and number through Akt/FoxO1/Maf1 signaling, which, together with autophagy, enhanced DENV replication and virus production. We therefore provide mechanistic insight into the interaction between lipid metabolism and the DENV replication cycle.

Effect of 4-week electroacupuncture intervention on "Browning" of white fat in rats and its mechanism

Objective: To investigate the effects of 4-week electroacupuncture intervention on "Browning" of white fat in rats, and to explore its molecular mechanisms. Methods: Twenty-four 8-week-old male SD rats were randomly divided into sedentary group (Sed), aerobic exercise group (Exe) and electroacupuncture group (ElA), 8 rats in each group. Exe group used 65% Max oxygen uptake intensity treadmill exercise, 1 h/d,6 d/w, while the ElA group used electric acupuncture to stimulate "zusanli" and "tianshu" points, 20 min/d,6 d/w, and the weight of rats was recorded every week. After 4 weeks of intervention, blood samples were collected from the apex and abdominal aorta. The wet weight of scapular fat and perirenal fat of rats was detected and the body fat and the serum levels of Irisin were determined. What's more, the expressions of adenosine 5'-monophosphate activated protein kinase-α (AMPKα), phosphorylation of adenosine 5'-monophosphate activated protein kinase-α (p-AMPKα), peroxisome proliferator activated receptor γ coactivator-1α (PGC-1α), fibronectin type III domain containing 5 (FNDC5) and uncoupling protein (UCP1) and brown adipose tissue lipid droplets in rats were detected. Results: Compared with the Sed group, the weight gain of rats in the Exe and ElA groups was decreased significantly from the second week. After 4 weeks, the body weight and body fat of the Exe and ElA groups were decreased significantly (P＜0.01), while there was no significant difference between the Exe and ElA groups (P＞0.05). ②After 4 weeks of intervention, the white fat wet weight of ElA group and Exe group was significantly was reduced (P＜0.05 or P＜0.01). ③The serum levels of Irisin in Exe and ElA groups were significantly increased (P＜0.05), and the expressions of p-AMPKα/AMPKα, PGC-1α, FNDC5 in the gastrocnemius and the expressions of UCP1 in white fat and brown adipose tissue of Exe and ElA groups were increased (P＜0.05). ④The area of lipid droplets in white and brown adipose tissue of Exe and ElA groups was significantly reduced (P＜ 0.01). Conclusion: 4 weeks of electroacupuncture intervention can effectively control the weight of rats and induce "browning" of white fat, and its effect was similar to aerobic exercise, which may be release Irisin through the AMPKα-PGC-1α-FNDC5-Irisin signaling pathway, and then "crosstalk" with adipose tissue, up-regulate the expression of UCP1, and induce "browning" of white adipose tissue.

Hepatic Synaptotagmin 1 is involved in the remodelling of liver plasma- membrane lipid composition and gene expression in male Apoe-deficient mice consuming a Western diet

Background and aims.The molecular mechanisms by which the liver develops steatotic disease still remain unclear. Previous studies using nutritional and genetic models of hepatic steatosis in mice showed that liver synaptotagmin 1 (Syt1) expression was associated with lipid droplet area. Hepatic Syt1 overexpression was used as a tool to explore its effect on hepatic and plasma lipids. Methods and resultsTo find out a cause-effect, hepatic mouse Syt1 mRNA was cloned into a vector driving hepatocyte-specific expression and administered by hydrodynamic injection to male Apoe-deficient mice fed on a Western diet, the latter as a model of rapid spontaneous steatosis development. Hepatic microsomal, large vesicle, lysosomal and plasma membrane fractions were enriched in SYT1 protein following gene overexpression. In these conditions, very low density lipoprotein esterified cholesterol increased. Likewise, the transgene caused an alteration in lipid droplet surface and a positive correlation between Syt1 expression and hepatic total cholesterol content. A lipidomic approach evidenced a decrease in lysophosphatidylcholine, phosphatidylcholine and triglycerides in isolated plasma membrane fraction. Expressions of genes involved in biosynthesis of bile acids, fatty acid metabolism, lipoprotein dynamics and vesicular transport were modified by the increased SYT1 expression. ConclusionsThese results indicate that this protein is involved in hepatic management of lipids and in the regulation of genes involved in lipid metabolism.