Adipose Triglyceride Lipase Levels Research Articles

Black Ginger Extract Suppresses Fat Accumulation by Regulating Lipid Metabolism in High-Fat Diet-Fed Mice.

This study investigated the antiobesity effects of black ginger extract (BGE) in high-fat diet (HFD)-induced obese mice. Mice were divided into six groups: normal diet control (NC, AIN-93G normal diet), 60% HFD control (HFD), HFD containing metformin at 250 mg/kg b.w. (Met, positive control), and HFD containing BGE at 5, 10, or 20 mg/kg b.w. for 15 weeks. BGE administration significantly prevented HFD-induced increases in weight gain, organ weight, and adipose tissue mass. Furthermore, it resulted in decreased adipogenesis and lipogenesis-related factors, including phosphorylated mitogen-activated protein kinase, peroxisome proliferator-activated receptor gamma, CCAAT/enhancer-binding proteins, sterol regulatory element-binding protein 1, phosphorylated cAMP response element-binding protein, glucose-6-phosphate dehydrogenase, fatty acid synthase, dephosphorylated ATP-citrate lyase, dephosphorylated acetyl-CoA carboxylase, and lipoprotein lipase, in white adipose tissues. Moreover, BGE administration enhanced lipolysis in white adipose tissue, as evidenced by elevated levels of adipose triglyceride lipase, phosphorylated hormone-sensitive lipase, and protein kinase A, along with reduced levels of perilipin and phosphodiesterase 3B. BGE induced thermogenesis in brown adipose tissues, as reflected by the increased expression of AMP-activated protein kinase, uncoupling protein 1, and carnitine palmitoyltransferase 1 and decreased levels of fatty acid-binding protein 4. In conclusion, this study provides comprehensive evidence supporting the antiobesity effects of BGE, elucidating the underlying molecular mechanisms involved in preventing weight gain, suppressing adipogenesis, promoting lipolysis, and stimulating thermogenesis. These findings suggest the potential therapeutic utility of BGE in combating obesity and associated metabolic disorders (KHGASP-2023-034).

The loss of antioxidant activities impairs intestinal epithelium homeostasis by altering lipid metabolism

Reactive oxygens species (ROS) are common byproducts of metabolic reactions and could be at the origin of many diseases of the elderly. Here we investigated the role of ROS in the renewal of the intestinal epithelium in mice lacking catalase (CAT) and/or nicotinamide nucleotide transhydrogenase (NNT) activities. Cat−/− mice have delayed intestinal epithelium renewal and were prone to develop necrotizing enterocolitis upon starvation. Interestingly, crypts lacking CAT showed fewer intestinal stem cells (ISC) and lower stem cell activity than wild-type. In contrast, crypts lacking NNT showed a similar number of ISCs as wild-type but increased stem cell activity, which was also impaired by the loss of CAT. No alteration in the number of Paneth cells (PCs) was observed in crypts of either Cat−/− or Nnt−/− mice, but they showed an evident decline in the amount of lysozyme. Cat deficiency caused fat accumulation in crypts, and a fall in the remarkable high amount of adipose triglyceride lipase (ATGL) in PCs. Notably, the low levels of ATGL in the intestine of Cat −/− mice increased after a treatment with the antioxidant N-acetyl-L-cysteine. Supporting a role of ATGL in the regulation of ISC activity, its inhibition halt intestinal organoid development. These data suggest that the reduction in the renewal capacity of intestine originates from fatty acid metabolic alterations caused by peroxisomal ROS.

PGC-1α activation boosts exercise-dependent cellular response in the skeletal muscle

The role of Peroxisome proliferator-activated receptor-gamma coactivator alpha (PGC-1α) in fat metabolism is not well known. In this study, we compared the mechanisms of muscle-specific PGC-1α overexpression and exercise-related adaptation-dependent fat metabolism. PGC-1α trained (PGC-1α Ex) and wild-trained (wt-ex) mice were trained for 10 weeks, five times a week at 30 min per day with 60 percent of their maximal running capacity. The PGC-1α overexpressed animals exhibited higher levels of Fibronectin type III domain-containing protein 5 (FNDC5), 5' adenosine monophosphate-activated protein kinase alpha (AMPK-α), the mammalian target of rapamycin (mTOR), Sirtuin 1 (SIRT1), Lon protease homolog 1 (LONP1), citrate synthase (CS), succinate dehydrogenase complex flavoprotein subunit A (SDHA), Mitofusin-1 (Mfn1), endothelial nitric oxide synthase (eNOS), Hormone-sensitive lipase (HSL), adipose triglyceride lipase (ATGL), G protein-coupled receptor 41 (GPR41), and Phosphatidylcholine Cytidylyltransferase 2 (PCYT2), and lower levels of Sirtuin 3 (SIRT3) compared to wild-type animals. Exercise training increased the protein content levels of SIRT1, HSL, and ATGL in both the wt-ex and PGC-1α trained groups. PGC-1α has a complex role in cellular signaling, including the upregulation of lipid metabolism-associated proteins. Our data reveals that although exercise training mimics the effects of PGC-1α overexpression, it incorporates some PGC-1α-independent adaptive mechanisms in fat uptake and cell signaling.

Prevention of high-fat-diet-induced obesity in mice by soluble dietary fiber from fermented and unfermented millet bran

Obesity-related diabetes, cardiovascular disease, and hypertension pose many risks to human health. Thus, mice on a high-fat diet were gavaged with millet bran (unfermented/fermented) soluble dietary fiber (RSDF/FSDF, 500 mg·kg−1) for 10 weeks in current research, and then evaluated the various biological indicators. These findings revealed that RSDF and FSDF supplements could prevent fat synthesis by inhibiting sterol regulatory element-binding protein-1c gene expression. The RSDF supplements can also accelerate fat catabolism through enhanced the mRNA expression levels of adipose triglyceride lipase and peroxisome proliferator-activated receptor α. FSDF supplements can prevent obesity by decreasing 3-hydroxy-3-methyl-glutaryl-CoA reductase expression and increasing cholesterol 7α-hydroxylase expression. Moreover, FSDF also controls obesity development by lowering total cholesterol and low-density lipoprotein cholesterol levels in the blood, triglyceride, total cholesterol, and bile acid levels in the liver. Notably, FSDF supplements can promote Bacteroides and Prevotella propagation; excretive propionic acid binds to free fatty acid receptor 2/3 and then stimulates intestinal epithelial cells to generate glucagon-like-peptide-1 and peptide YY, which can reduce food and energy intake and ultimately prevent obesity. All evidence suggests that FSDF supplements play a crucial role in preventing obesity.

ATGL promotes colorectal cancer growth by regulating autophagy process and SIRT1 expression.

CRC is a common malignant tumor in the gastrointestinal tract, and its incidence has increased significantly in recent years. Several studies revealed that lipid metabolism reprogramming contributed to tumorigenicity and malignancy by interfering with energy production, membrane formation, and signal transduction in cancers. ATGL is a kind of hydroxy fatty acid ester of fatty acid synthase, and its role in tumor remains controversial. We compared levels of adipose triglyceride lipase (ATGL) in human CRC specimens to adjacent specimens. To validate the effect of ATGL on the proliferation ability of CRC, CCK8 assay and clone formation assay were performed. To evaluate whether autophagy process takes part in the effect of ATGL on CRC proliferation, the value of LC3-II/LC3-I was detected by western blot and we blocked the SIRT1 to detect value of LC3-II/LC3-I and p62 via western blot. In the end, we detected the value of SIRT1 in CRC specimens. We found that ATGL showed high expression in CRC and positively correlated with clinical stage, indicating poor prognosis of CRC. Moreover, ATGL significantly promoted tumor cell proliferation in vitro. Mechanistically, ATGL promoted CRC cells proliferation by blocking mTOR signaling pathway and activating autophagy process. Further, ATGL regulated autophagy process through triggering SIRT1 expression. Our results reveal that ATGL promotes colorectal cancer growth by up regulating autophagy process and SIRT1 expression.

Exercise Equals the Mobilization of Visceral versus Subcutaneous Adipose Fatty Acid Molecules in Fasted Rats Associated with the Modulation of the AMPK/ATGL/HSL Axis.

Combining exercise with fasting is known to boost fat mass-loss, but detailed analysis on the consequential mobilization of visceral and subcutaneous WAT-derived fatty acids has not been performed. In this study, a subset of fasted male rats (66 h) was submitted to daily bouts of mild exercise. Subsequently, by using gas chromatography-flame ionization detection, the content of 22 fatty acids (FA) in visceral (v) versus subcutaneous (sc) white adipose tissue (WAT) depots was compared to those found in response to the separate events. Findings were related to those obtained in serum and liver samples, the latter taking up FA to increase gluconeogenesis and ketogenesis. Each separate intervention reduced scWAT FA content, associated with increased levels of adipose triglyceride lipase (ATGL) protein despite unaltered AMP-activated protein kinase (AMPK) Thr172 phosphorylation, known to induce ATGL expression. The mobility of FAs from vWAT during fasting was absent with the exception of the MUFA 16:1 n-7 and only induced by combining fasting with exercise which was accompanied with reduced hormone sensitive lipase (HSL) Ser563 and increased Ser565 phosphorylation, whereas ATGL protein levels were elevated during fasting in association with the persistently increased phosphorylation of AMPK at Thr172 both during fasting and in response to the combined intervention. As expected, liver FA content increased during fasting, and was not further affected by exercise, despite additional FA release from vWAT in this condition, underlining increased hepatic FA metabolism. Both fasting and its combination with exercise showed preferential hepatic metabolism of the prominent saturated FAs C:16 and C:18 compared to the unsaturated FAs 18:1 n-9 and 18:2 n-6:1. In conclusion, depot-specific differences in WAT fatty acid molecule release during fasting, irrelevant to their degree of saturation or chain length, are mitigated when combined with exercise, to provide fuel to surrounding organs such as the liver which is correlated with increased ATGL/ HSL ratios, involving AMPK only in vWAT.

Heat-Killed Enterococcus faecalis Inhibit FL83B Hepatic Lipid Accumulation and High Fat Diet-Induced Fatty Liver Damage in Rats by Activating Lipolysis through the Regulation the AMPK Signaling Pathway

Continuous consumption of high-calorie meals causes lipid accumulation in the liver and liver damage, leading to non-alcoholic fatty liver disease (NAFLD). A case study of the hepatic lipid accumulation model is needed to identify the mechanisms underlying lipid metabolism in the liver. In this study, the prevention mechanism of lipid accumulation in the liver of Enterococcus faecalis 2001 (EF-2001) was extended using FL83B cells (FL83Bs) and high-fat diet (HFD)-induced hepatic steatosis. EF-2001 treatment inhibited the oleic acid (OA) lipid accumulation in FL83B liver cells. Furthermore, we performed lipid reduction analysis to confirm the underlying mechanism of lipolysis. The results showed that EF-2001 downregulated proteins and upregulated AMP-activated protein kinase (AMPK) phosphorylation in the sterol regulatory element-binding protein 1c (SREBP-1c) and AMPK signaling pathways, respectively. The effect of EF-2001 on OA-induced hepatic lipid accumulation in FL83Bs enhanced the phosphorylation of acetyl-CoA carboxylase and reduced the levels of lipid accumulation proteins SREBP-1c and fatty acid synthase. EF-2001 treatment increased the levels of adipose triglyceride lipase and monoacylglycerol during lipase enzyme activation, which, when increased, contributed to increased liver lipolysis. In conclusion, EF-2001 inhibits OA-induced FL83B hepatic lipid accumulation and HFD-induced hepatic steatosis in rats through the AMPK signaling pathway.

Nomegestrol acetate ameliorated adipose atrophy in a rat model of cisplatin‑induced cachexia.

Cachexia, a complex disorder that results in depletion of adipose tissue and skeletal muscle, is driven by anorexia, metabolic abnormalities and inflammation. There are limited therapeutic options for this syndrome. Previous evidence has demonstrated that increasing adipose tissue may improve quality of life and survival outcomes in cachexia. Cisplatin, as a chemotherapy drug, also causes cachexia during antitumor therapy due to its adverse effects. To establish a rat model of cachexia, the animals were intraperitoneally treated with cisplatin at doses of 1, 2 and 3 mg/kg, and the rats that responded to cisplatin at the optimal dose were used to test the effect of nomegestrol acetate (NOMAc). Rats that were assessed to be sensitive to cisplatin were randomly grouped and intragastrically administered vehicle, 5 or 10 mg/kg megestrol acetate (MA) or 2.5, 5 or 10 mg/kg NOMAc. The body weights and food consumption of the rats were assessed. Serum IL-6 and TNF-α levels were assessed using ELISA. The protein expression levels of adipose triglyceride lipase (ATGL), hormone-sensitive lipase (HSL), peroxisome proliferator activated receptor γ (PPARγ), fatty acid synthase (FASN) and sterol regulatory element-binding protein-1 (SREBP-1) from inguinal white adipose tissue (iWAT) and epididymal white adipose tissue (eWAT) were evaluated using western blotting. The optimal way to establish a chemotherapy-induced rat model of cachexia demonstrated in the present study was to intraperitoneally administer the rats with 2 mg/kg cisplatin for 3 consecutive days. NOMAc (2.5, 5 mg/kg) and MA (10 mg/kg) were able to significantly ameliorate the loss of body weight in the cisplatin-induced cachectic rats. NOMAc significantly reduced the serum levels of TNF-α at 10 mg/kg. Morphologically, iWAT atrophy, with a remarkable reduction in adipocyte volume, was observed in the cisplatin-induced cachectic rats, but the effects were reversed by administering 5, 10 mg/kg NOMAc or 10 mg/kg MA. Furthermore, 2.5 mg/kg NOMAc markedly reduced the protein expression levels of the lipolysis genes HSL and ATGL, and 5 mg/kg NOMAc markedly enhanced the protein expression levels of adipogenesis genes, including FASN, SREBP-1 and PPARγ in iWAT but not in eWAT. NOMAc was demonstrated to improve cachexia at lower doses compared with MA. Overall, NOMAc is likely to be a promising candidate drug for ameliorating cancer cachexia induced by cisplatin.

Prolyl Isomerase Pin1 Impacts on Metabolism in Muscle and Adipocytes

Prolyl isomerase Pin1 is associated with various substrates and controls their functions through the isomerization of proline. Interestingly, a high fat diet increases Pin1 levels in adipose tissues. Accordingly, we investigated how Pin1 regulates energy metabolism in adipose tissues. Currently, adipocytes are divided into three types with distinct features. White adipocytes (WATs) store energy as triglycerides under fed conditions and release non-esterified fatty acids and glycerol through lipolysis while fasting. Brown and beige adipocytes, which exist in subcutaneous fat (scWAT), promote energy consumption through thermogenesis. We found that Pin1 impacts both thermogenesis and lipolysis upon interaction with distinct substrates. When mice were exposed to cold stress, both brown adipose tissues (BAT) and scWAT from adipocyte-specific Pin1 knockout (KO) mice showed higher expression levels of thermogenic genes in comparison to those from wild-type mice. Furthermore, we observed that Pin1 binds to the PRDM16 transcriptional cofactor, a major contributor to thermogenic programs, and promotes its degradation. Therefore, Pin1 suppresses thermogenesis. Meanwhile, in white adipocytes, Pin1 is involved in lipolysis. Pin1 deficiency enhanced lipolysis activity in epididymal WAT (epiWAT), but not in scWAT and BAT. In epiWAT, Pin1 interacts with adipose triglyceride lipase (ATGL) which is a rate-limiting enzyme for lipolysis, and downregulates ATGL levels. Finally, adipocyte-specific Pin1 KO mice have less body weight and better glucose metabolism under high fat diet conditions. These observations indicate that Pin1 is involved in the function of adipocytes through its association with PRDM16 and ATGL. Pin1 inhibitors could have therapeutic applications in the treatment of obesity.

Role of Corticosterone in Lipid Metabolism in Broiler Chick White Adipose Tissue.

Excessive accumulation of body fat in broiler chickens has become a serious problem in the poultry industry. However, the molecular mechanism of triglyceride accumulation in chicken white adipose tissue (WAT) has not been elucidated. In the present study, we investigated the physiological importance of the catabolic hormone corticosterone, the major glucocorticoid in chickens, in the regulation of chicken WAT lipid metabolism. We first examined the effects of fasting on the mRNA levels of lipid metabolism-related genes associated with WAT, plasma corticosterone, and non-esterified fatty acid (NEFA). We then examined the effects of corticosterone on the expression of these genes in vivo and in vitro. In 10-day-old chicks, 3 h of fasting significantly decreased mRNA levels of lipoprotein lipase (LPL) in WAT and significantly elevated plasma concentrations of NEFA. Six hours of fasting significantly increased mRNA levels of adipose triglyceride lipase (ATGL) in WAT and significantly elevated plasma concentrations of corticosterone. On the other hand, fasting significantly reduced mRNA levels of LPL in WAT and elevated plasma concentrations of NEFA in 29-day-old chicks without affecting mRNA levels of ATGL in WAT or plasma corticosterone concentrations. Oral administration of corticosterone significantly reduced mRNA levels of LPL and significantly increased the mRNA levels of ATGL in WAT in 29-day-old chicks without affecting plasma NEFA concentrations. The addition of corticosterone to primary chicken adipocytes significantly increased mRNA levels of ATGL, whereas mRNA levels of LPL tended to decrease. NEFA concentrations in the culture medium were not influenced by corticosterone levels. These results suggest that plasma corticosterone partly regulates the gene expression of lipid metabolism-related genes in chicken WAT and this regulation is different from the acute elevation of plasma NEFA due to short-term fasting.

Peroxisomal \u03b2-oxidation acts as a sensor for intracellular fatty acids and regulates lipolysis

To liberate fatty acids (FAs) from intracellular stores, lipolysis is regulated by the activity of the lipases adipose triglyceride lipase (ATGL), hormone-sensitive lipase and monoacylglycerol lipase. Excessive FA release as a result of uncontrolled lipolysis results in lipotoxicity, which can in turn promote the progression of metabolic disorders. However, whether cells can directly sense FAs to maintain cellular lipid homeostasis is unknown. Here we report a sensing mechanism for cellular FAs based on peroxisomal degradation of FAs and coupled with reactive oxygen species (ROS) production, which in turn regulates FA release by modulating lipolysis. Changes in ROS levels are sensed by PEX2, which modulates ATGL levels through post-translational ubiquitination. We demonstrate the importance of this pathway for non-alcoholic fatty liver disease progression using genetic and pharmacological approaches to alter ROS levels in vivo, which can be utilized to increase hepatic ATGL levels and ameliorate hepatic steatosis. The discovery of this peroxisomal β-oxidation-mediated feedback mechanism, which is conserved in multiple organs, couples the functions of peroxisomes and lipid droplets and might serve as a new way to manipulate lipolysis to treat metabolic disorders.

Effect of Betaine Diet on Growth Performance, Carcass Quality and Fat Deposition in Finishing Ningxiang Pigs.

Simple SummaryExcessive fat deposit is one of the major problems in finishing Ningxiang pigs, and adversely affects the breeding. The study aimed to investigate the effects of diet with betaine supplementation (basal diet + 0.2% betaine) on the growth performance, slaughter performance, meat quality and the genes expression related to fat deposition in finishing Ningxiang pigs. The results indicated that diet with betaine supplementation decreased back fat thickness and fat percentage, and increased the lean meat percentage as well. In addition, it reduced the fat deposition by regulating the genes expression. These findings provided a reference for breeding Ningxiang pigs. The present study was conducted to investigate the effects of diet with betaine supplementation on the growth performance, carcass quality and fat deposition in finishing Ningxiang pigs. A total of 24 Ningxiang pigs (43.6 ± 5.34 kg of average body weight) was randomly divided into two groups, with 6 replicates per treatment and 2 pigs per replicate. The treatments included a control group (basal diet) and a test group (basal diet + 0.2% betaine). The whole trial lasted 81 days. At the end of the experiment, one pig (close to the average body weight of all experimental pigs) per replicate was slaughtered to determine the carcass traits, meat quality and the mRNA expression levels of genes relate to fat deposition (one pig per replicate was randomly selected and fasted for 12 h, n = 6). Results indicated that growth performance was not changed with betaine supplementation. However, dietary with betaine supplementation decreased back fat thickness and fat percentage, and increased the lean meat percentage as well (p < 0.05). In addition, diet with betaine supplementation reduced drip loss, water loss, cooking loss, shear force and b × 24 h value of meat (p < 0.05). There was no difference in total moisture, ether extract and crude protein of longissimus thoracis between the control and test group. Dietary with betaine supplementation decreased ether extract and total cholesterol (p < 0.05) in liver. Dietary with betaine supplementation upregulated the mRNA expression levels of adipose triglyceride lipase (ATGL) and sirtuin 1 (Sirt1), while downregulated the mRNA expression levels of fatty acid synthase (FAS) and acetyl CoA carboxylase (ACC) in subcutaneous fat of back (p < 0.05). Besides, dietary with betaine supplementation upregulated the fatty acid binding protein 4 (FABP4) mRNA expression of longissimus thoracis in finishing Ningxiang pigs (p < 0.05). These results showed that diet supplemented with betaine could improve the slaughtering performance and meat quality, and regulate the genes expression to affect the fat deposition in finishing Ningxiang pigs.

Elevated ATGL in colon cancer cells and cancer stem cells promotes metabolic and tumorigenic reprogramming reinforced by obesity

Obesity is a worldwide epidemic associated with increased risk and progression of colon cancer. Here, we aimed to determine the role of adipose triglyceride lipase (ATGL), responsible for intracellular lipid droplet (LD) utilization, in obesity-driven colonic tumorigenesis. In local colon cancer patients, significantly increased ATGL levels in tumor tissue, compared to controls, were augmented in obese individuals. Elevated ATGL levels in human colon cancer cells (CCC) relative to non-transformed were augmented by an obesity mediator, oleic acid (OA). In CCC and colonospheres, enriched in colon cancer stem cells (CCSC), inhibition of ATGL prevented LDs utilization and inhibited OA-stimulated growth through retinoblastoma-mediated cell cycle arrest. Further, transcriptomic analysis of CCC, with inhibited ATGL, revealed targeted pathways driving tumorigenesis, and high-fat-diet obesity facilitated tumorigenic pathways. Inhibition of ATGL in colonospheres revealed targeted pathways in human colonic tumor crypt base cells (enriched in CCSC) derived from colon cancer patients. In CCC and colonospheres, we validated selected transcripts targeted by ATGL inhibition, some with emerging roles in colonic tumorigeneses (ATG2B, PCK2, PGAM1, SPTLC2, IGFBP1, and ABCC3) and others with established roles (MYC and MUC2). These findings demonstrate obesity-promoted, ATGL-mediated colonic tumorigenesis and establish the therapeutic significance of ATGL in obesity-reinforced colon cancer progression.

Increased expression level of ANGPTL8 in white adipose tissue under acute and chronic cold treatment

BackgroundAngiopoietin-like proteins (ANGPTL), primarily 3, 4, and 8, play a major role in maintaining energy homeostasis by regulating triglyceride metabolism. This study evaluated the level of ANGPTL3, 4, and 8 in the liver, brown adipose tissue (BAT), and subcutaneous white adipose tissue (SAT) of mice maintained under acute and chronic cold conditions.MethodsC57BL/6J mice were exposed to cold temperature (4 °C) for 10 days with food provided ad libitum. Animal tissues were harvested at Day 0 (Control group, n = 5) and Days 1, 3, 5, and 10 (cold treatment groups, n = 10 per group). The expression levels of various genes were measured in the liver, SAT, and BAT. ANGPTL3, 4, and 8 expressions were measured in the liver. ANGPTL4, 8, and genes involved in browning and lipid metabolism [uncoupling protein 1 (UCP1), lipoprotein lipase (LPL), and adipose triglyceride lipase (ATGL)] were measured in SAT and BAT. Western blotting (WB) analysis and immunohistochemistry (IHC) were performed to confirm ANGPTL8 expression in these tissues.ResultsThe expressions of ANGPTL3 and 8 mRNA were significantly reduced in mouse liver tissues after cold treatment (P < 0.05); however, the expression of ANGPTL4 was not significantly altered. In BAT, ANGPTL8 expression was unchanged after cold treatment, whereas ANGPTL4 expression was significantly reduced (P < 0.05). ANGPTL4 levels were also significantly reduced in SAT, whereas ANGPTL8 gene expression exhibited over a 5-fold increase. Similarly, UCP1 gene expression was also significantly increased in SAT. The mRNA levels of LPL and ATGL showed an initial increase followed by a gradual decrease with an increase in the days of cold exposure. ANGPTL8 protein overexpression was further confirmed by WB and IHC.ConclusionsThis study shows that exposure to acute and chronic cold treatment results in the differential expression of ANGPTL proteins in the liver and adipose tissues (SAT and BAT). The results show a significant reduction in ANGPTL4 in BAT, which is linked to improved thermogenesis in response to acute cold exposure. ANGPTL8 was activated under acute and chronic cold conditions in SAT, suggesting that it is involved in regulating lipolysis and enhancing SAT browning.

LIPOSA pharmacopuncture, a new herbal formula, affects localized adiposity by regulating lipid metabolism in vivo.

Localized adiposity is a serious aesthetic problem and a well-known health risk factor. There is a growing interest in minimally invasive treatment options for excessive fat accumulation, such as pharmacopuncture. LIPOSA is a newly developed pharmacopuncture formula from three natural herbs: The tuber of Pinellia ternata (Thunb.) Breitenb., the whole plant of Taraxacum platycarpum Dahlst. and the root of Astragalus membranaceus Bunge. The present study investigated the effects of pharmacopuncture treatment with LIPOSA on localized adiposity. Male C57BL/6J mice were fed high fat diet for 8 weeks to induce obesity. Then, 100 µl LIPOSA was injected into the left-side inguinal fat pad at various concentrations, including 13.35, 26.7 and 53.4 mg/ml. Normal saline was injected into the right-side inguinal fat pad of each mouse as a control. The treatment was performed three times per week for 2 weeks. The weight and histological changes were analyzed in the inguinal fat pad of the obese mice. The expression levels of adipose triglyceride lipase (ATGL), hormone-sensitive lipase (HSL), autophagy-related gene (ATG)5, ATG7 and LC3-II, as lipophagy-related factors, were evaluated to confirm the lipid-catabolic effects of LIPOSA. LIPOSA pharmacopuncture markedly decreased the weight of the fat tissue and the size of the adipocytes in the inguinal region of the mouse models of obesity in a dose-dependent manner. The expression levels of ATGL, HSL, ATG5, ATG7 and LC3-II were significantly increased by the LIPOSA treatments. In addition, LIPOSA pharmacopuncture was found to decrease the expression levels of ACC, PPAR-γ and PEPCK. The results indicated that subcutaneous injection of LIPOSA can degrade local fat and induce lipophagic and lipase activation effects. In addition, lipid metabolism related to fat accumulation was regulated by the LIPOSA treatment. The present study suggests that LIPOSA pharmacopuncture can be a non-surgical alternative in the treatment of localized adiposity.

Single-cell RNA sequencing of preadipocytes reveals the cell fate heterogeneity induced by melatonin.

Obesity is a global epidemic health disorder and associated with several diseases. Body weight-reducing effects of melatonin have been reported; however, no investigation toward examining whether the beneficial effects of melatonin are associated with preadipocyte heterogeneity has been reported. In this study, we profiled 25071 transcriptomes of normal and melatonin-treated preadipocytes using scRNA-seq. By tSNE analysis, we present a cellular-state landscape for melatonin-treated preadipocytes that covers multiple-cell subpopulations, defined as cluster 0 to cluster 13. Cluster 0 and cluster 1 were the largest components of normal and melatonin-treated preadipocytes, respectively. G0S2, an inhibitor of adipose triglyceride lipase (ATGL), was significantly upregulated in cluster 0 and downregulated in cluster 1. We redefined cluster 0 as the G0S2-positive cluster (G0S2+ ) and cluster 1 as the G0S2-negative cluster (G0S2- ). Through pseudotime analysis, the G0S2- cluster cell differentiation trajectory was divided into three major structures, that is, the prebranch, the lipid catabolism branch, and the cell fate 2 branch. In vitro, G0S2 knockdown enhanced the expression levels of ATGL, BAT markers and fatty acid oxidation-related genes, but inhibited C/EBPα and PPARγ expression. In vivo, knockdown of G0S2 reduced the body weight gain in high-fat-fed mice. The beneficial effects of the G0S2- cell cluster in promoting lipolysis and inhibiting adipogenesis are dependent on two major aspects: first, downregulation of the G0S2 gene in the G0S2- cluster, resulting in activation of ATGL, which is responsible for the bulk of triacylglycerol hydrolase activity; and second, upregulation of FABP4 in the G0S2- cluster, resulting in inhibition of PPARγ and further reducing adipogenesis.

Low Molecular Pectin Inhibited the Lipid Accumulation by Upregulation of METTL7B

Inhibition of lipid accumulation is the key step to prevent nonalcoholic fatty liver (NAFL) progressing to nonalcoholic steatohepatitis. We aimed to study the effect of low-molecular-weight citrus pectin (LCP) against lipid accumulation and the underlying mechanism. Oleic acid (OA)-induced lipid deposition in HepG2 cells was applied to mimic in vitro model of lipid accumulation. Oil Red O (ORO) stain result showed lipid accumulation was significantly reduced, and levels of adipose triglyceride lipase (ATGL) and carnitine palmitoyltransferase-1 (CPT-1), involved in triacylglycerol catabolism and fatty acid β-oxidation, detected by RT-qPCR were increased after OA-stimulated HepG2 cells treated with LCP. RNA sequencing analysis identified 740 differentially expressed genes (DEGs) in OA-stimulated HepG2 cells treated with the LCP group (OA+LCP group), and bioinformatics analysis indicated that some DEGs were enriched in lipid metabolism-related processes and pathways. The expression of the top 8 known DEGs in the OA+LCP group was then verified by RT-qPCR, which showed that fold change (abs) of METTL7B was the highest among the 8 candidates. In addition, overexpression of METTL7B in HepG2 cells significantly inhibited the lipid accumulation and enhanced levels of ATGL and CPT-1. In conclusion, LCP inhibited lipid accumulation through the upregulation of METTL7B, and further enhancement of ATGL and CPT-1 levels. LCP is expected to develop as a promising agent to ameliorate fat accumulation in NAFL.

Dietary lipid levels affected growth performance, lipid accumulation, inflammatory response and apoptosis of japanese seabass (lateolabraxjaponicus)

An eight weeks feeding trial was conducted to investigate the effects of dietary lipid levels on growth performance, lipid metabolism and immune response of Japanese seabass (Lateolabrax japonicus). Five diets were formulated with gradient dietary lipid levels (79.6, 104.4, 129.1, 154.9 and 178.6 g kg−1). Results revealed that growth and feed utilization of fish were significantly lower in group L178.6 than other groups (p < 0.05). Lipid accumulation in whole body, muscle and intraperitoneal were increased with increasing dietary lipid levels. The mRNA levels of adipose triglyceride lipase, carnitine palmitoyl transferase 1, acetyl CoA carboxylase, cholesterol 7 alpha-hydroxylase and retinoid X receptor in liver were also increased with increasing dietary lipid levels (p < 0.05). The mRNA levels of apolipoprotein A1 and peroxisome proliferator activating receptor α were higher in fish fed L178.6 than those fed other diets. Oxidative stress in plasma and liver were induced when dietary lipid exceed 154.9 g kg−1. L154.9 and L178.6 significantly increased the inflammatory related gene expression of fish. These results suggested that high-fat diet impaired the growth performance and induced lipid accumulation, inflammation and apoptosis of Japanese seabass. The suitable dietary lipid level of Japanese seabass may not exceed 129.1 g kg−1.

Circular RNA cMras Suppresses the Progression of Lung Adenocarcinoma Through ABHD5/ATGL Axis Using NF-κB Signaling Pathway.

Background: Lung adenocarcinoma (LAC) is a common malignancy worldwide. Emerging findings indicated that circular RNAs possess complex capacities of gene modulation in tumorigenesis and metastasis. Nevertheless, the role of circular RNA in LAC is still largely unknown. Materials and Methods: The level of circular RNA cMras (circ_cMras), alpha-beta hydrolase domain 5 (ABHD5), and adipose triglyceride lipase (ATGL) was determined by quantitative real-time polymerase chain reaction assay. Protein levels of ABHD5, ATGL, p53, p65, and phospho-p65 (p-p65) were examined by Western blot. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) was used to detect cell proliferation in vitro. Cell apoptosis was estimated using flow cytometry. Transwell assay was used to measure cell migration and invasion in A549 and HCC827 cells. Finally, the role of circ_cMras was explored using xenograft tumor model. Results: Low levels of circ_cMras, ABHD5, and ATGL were observed in LAC tissues and cells. Upregulation of circ_cMras could hamper tumor aggression in vitro and in vivo, exhibiting as the inhibition of cell proliferation, migration, invasion, and promotion of cell apoptosis, as well as the inhibition on tumor growth in vivo. Moreover, ABHD5 deletion could overturn the effects of circ_cMras overexpression on cell behaviors in LAC cells. Furthermore, the inhibiting effects of ABHD5 on cell aggression were reversed by ATGL deficiency in vitro. Mechanically, circ_cMras/ABHD5/ATGL axis exerted its role through NF-κB signaling pathway in LAC cells. Conclusion: Circ_cMras exerted its function through ABHD5/ATGL axis using NF-κB signaling pathway in LAC, which might provide a novel insight for the diagnosis and prognosis of LAC.

Abstract 2547: USP18 promotes lipolysis, fatty acid oxidation and lung cancer growth

Abstract Ubiquitin specific peptidase 18 (USP18) is the Interferon-Stimulated Gene 15 (ISG15) deconjugase that stabilizes target proteins by removing ISG15 from substrate proteins. We found that USP18 null mice have lower lipolysis rates, altered fat to body weight ratios and marked cold sensitivity. These findings implicated USP18 as a regulator of lipid and fatty acid metabolism. Prior work established that USP18 can promote lung tumorigenesis. We examined whether this occurs in lung cancer cells through altered lipid and fatty acid metabolism. The siRNA knockdown of USP18 downregulated Adipose Triglyceride Lipase (ATGL) and this reduced lipolysis. In contrast, engineered gain of USP18 expression upregulated ATGL and increased lipolysis. Notably, Ubiquitin Activating Enzyme E1 Like Protein (UBE1L) promoted ISG15-conjugated destabilization of ATGL protein. Immunoprecipitation experiments confirmed that ISG15 can covalently conjugate to ATGL. Protein expression profiles of thermogenic regulators were examined in brown fat of USP18 null versus wild-type mice. Strikingly, the master thermoregulatory protein Uncoupling Protein 1 (UCP1) was markedly repressed in brown fat of USP18 null mice. In contrast, USP18 reconstitution augmented UCP1 levels. Engineered gain of USP18 expression stabilized UCP1 protein through reduced Ubiquitin conjugation to UCP1 in the examined lung cancer cell lines. Intriguingly, gain of UCP1 expression in both human and murine lung cancer cell lines promoted cellular proliferation and UCP1 knockdown reduced proliferation. The beta-hydroxybutyrate colorimetric assay determined that UCP1 overexpression promoted fatty acid beta-oxidation in lung cancer cells. Seahorse assays independently confirmed that gain of UCP1 expression increased fatty acid beta-oxidation. Expression profiles of USP18, ATGL and UCP1 species were interrogated using The Cancer Genome Atlas (TCGA). Lung adenocarcinoma and squamous cell carcinoma cases having higher USP18, ATGL and UCP1 levels had a statistically-significantly unfavorable survival. This association also occurred in renal chromophobe carcinoma and low grade gliomas. Together, these findings implicate the deubiquitinase USP18 as a novel molecular pharmacologic target that controls fatty acid metabolism as an energy source for lung cancer growth. These observations provide a strong rationale to uncover USP18 pharmacologic inhibitors that would combat lung and potentially other human cancers. Citation Format: Xi Liu, Yun Lu, Zibo Chen, Xiuxia Liu, Weiguo Hu, Lin Zheng, Yulong Chen, Mi Shi, Lisa Mustachio, Jason Roszik, Masanori Kawakami, Sarah Freemantle, Ethan Dmitrovsky. USP18 promotes lipolysis, fatty acid oxidation and lung cancer growth [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2547.