Hormone-sensitive Lipase Expression Research Articles

Metabolic fuel selection in rainbow trout: Coping with Intralipid infusion.

The impact of hyperlipidemia on fuel selection has never been investigated in fish. This study quantifies how Intralipid administration affects: (i) in vivo mobilization of lipids (lipolytic rate: Ra glycerol) and carbohydrates (hepatic glucose production: Ra glucose) in rainbow trout, and (ii) key proteins involved in the regulation of fuel metabolism that could explain changes in glycerol and glucose kinetics. Results show that Intralipid triples lipolytic rate (from 2.5 ± 0.5 to 7.8 ± 1.1 µmol glycerol kg-1 min-1) and inhibits glucose production by 36% (from 7.3 ± 0.9 to 4.7 ± 0.4 µmol kg-1 min-1). The stimulation of lipolysis is probably driven by lipase activation (gene expression of hormone sensitive lipase increases in muscle), or by mass action effect. Such a strong lipolytic response is quite surprising because baseline Ra glycerol is already particularly high in fish, and well known for its stability under a variety of stresses that have important effects in mammals. The reduction in trout Ra glucose is likely caused by a large decrease in glycogen mobilization because hepatic gluconeogenic pathway capacity may rise as a consequence of increases in gluconeogenesis gene transcript levels. In contrast to humans, which maintain steady glucose production in response to Intralipid infusion, rainbow trout appear to overcompensate increased gluconeogenic capacity with a disproportionately large inhibition of glycogen breakdown. Overall, these Intralipid-driven changes in glycerol and glucose kinetics allow fish to decrease their reliance on carbohydrates and amino acids by replacing them, in part, with fatty acids as metabolic fuels.

Dietary supplementation of grape seed proanthocyanidins improves growth performance, carcass traits, and meat quality in growing-finishing pigs

Grape seed proanthocyanidin (GSP) is a type of plant polyphenol with a wide variety of biological activities, such as antioxidant properties. This study investigated the effects of GSP supplementation on growth performance and meat quality in growing-finishing pigs. A total of 180 pigs (with an initial average body weight of 30.37 ± 0.66 kg) were randomly assigned to five treatments: a control diet or a control diet supplemented with GSP at 15, 30, 60, and 120 mg/kg. Results showed that GSP supplementation linearly increased the average daily gain (P = 0.048) and quadratically decreased the feed intake to gain ratio (P = 0.049) with the lowest values at 30 and 60 mg/kg GSP. Serum concentrations of immunoglobulins (Ig) (IgA, IgG, IgM), total antioxidative capacity, catalase, and total superoxide dismutase were elevated with the peak levels at 30 mg/kg GSP (P < 0.05). Serum glutathione peroxidase increased and malondialdehyde decreased quadratically (P < 0.05), with peak and trough levels at 120 and 60 mg/kg GSP, respectively. The GSP also improved dressing percentage and muscle redness (a*45 min) with optimal levels at 30 and 60 mg/kg (P < 0.05). Additionally, GSP supplementation quadratically reduced the muscle yellowness (b*24 h) and shear force (P < 0.05), with the lowest values at 120 mg/kg. The expression level of myosin heavy chain I in muscle was quadratically increased with maximum expression at 30 and 60 mg/kg (P = 0.015). Furthermore, the expression levels of fatty acid synthase, phosphoenolpyruvate carboxykinase (PEPCK), and glucokinase in the muscle were decreased quadratically (P < 0.05) with the lowest values at 120 mg/kg. Additionally, GSP supplementation at 60 mg/kg upregulated the expression of hepatic hormone-sensitive triglyceride lipase and PEPCK (P < 0.05). These results suggest that GSP enhances carcass characteristics and meat quality in growing-finishing pigs, potentially through improved antioxidative capacity, modified muscle fiber type distribution, and altered glucose-lipid metabolism in muscle and liver.

Bufalin induces ferroptosis by modulating the 2,4-dienoyl-CoA reductase (DECR1)-SLC7A11 axis in breast cancer

Breast cancer (BC) is a leading cause of cancer-related mortality worldwide. 2,4-dienoyl-CoA reductase (DECR1), an auxiliary component of beta-oxidation, has been recognized for its role in enhancing lipid peroxidation and inducing ferroptosis in prostate cancer. However, its involvement in breast cancer remains largely unexplored. Our study revealed a notably elevated expression of DECR1 in breast cancer tissues, which correlated with increased malignant characteristics. Importantly, the overexpression of DECR1 significantly enhanced proliferation and migration capabilities in MDA-MB-231 cells. Through a comprehensive high-content screening approach, we identified bufalin and its derivative as potent inhibitors of DECR1 expression. Notably, bufalin demonstrated the highest binding energy during molecular docking studies and was found to promote the degradation of DECR1 via autophagy and ubiquitination. Furthermore, bufalin induced ferroptosis in MDA-MB-231 cells by modulating levels of malondialdehyde (MDA), triglycerides (TG), reactive oxygen species (ROS) and Fe2+ while downregulating the expression of hormone-sensitive lipase (HSL), ferritin heavy chain protein 1 (FPN), solute carrier family 7 member 11 (SLC7A11), and glutathione peroxidase 4 (GPX4). These effects were counteracted by DECR1 overexpression. In vivo experiments demonstrated that bufalin inhibited the tumor growth, while decreasing the expression levels of HSL, FPN, SLC7A11, and GPX4, alongside increasing levels of 4-hydroxynonenal (4-HNE). Crucially, the ferroptosis effects induced by bufalin in vivo were also reversed by DECR1 overexpression. Subsequently, we discovered that SLC7A11 interacts with DECR1, inhibition of SLC7A11 led to decreased expression levels of DECR1 along with an accumulation of MDA and Fe2+, effects that were similarly reversed by DECR1 overexpression. Collectively, our findings suggest that targeted therapy against DECR1 combined with further inhibition of its downstream pathway involving SLC7A11/GPX4 may represent a promising strategy for treating breast cancer.

Glycerol Handling in Paired Visceral and Subcutaneous Adipose Tissues in Women with Normal Weight and Upper-Body Obesity.

In adipose tissue, reduced expression of the glycerol channel aquaporin 7 (AQP7) has been associated with increased accumulation of triglyceride. The present study determines the relative protein abundances of lipolytic enzymes, AQP7, and cytosolic phosphoenolpyruvate carboxykinase (PEPCK-C) in paired mesenteric and omental visceral adipose tissue (VAT) and abdominal and femoral subcutaneous adipose tissue (SAT) in women with either normal weight or upper-body obesity. No differences in the expression of hormone-sensitive lipase (HSL) or AQP7 were found between the two groups in the four depots. The expression of adipocyte triglyceride lipase (ATGL) and HSL were higher in omental VAT and femoral SAT than in mesenteric VAT in both groups of women. Similarly, AQP7 expression was higher in omental VAT than in mesenteric VAT. The expression of PEPCK-C was lower in omental VAT than in femoral SAT. No correlation between the expression of AQP7 and the mean adipocyte size was observed; however, the expression of PEPCK-C positively correlated with the mean adipocyte size. In conclusion, a depot-specific protein expression pattern was found for ATGL, HSL, AQP7, and PEPCK-C. The expression pattern supports that the regulation of AQP7 protein expression is at least in part linked to the lipolytic rate. Furthermore, the results support that the synthesis of glycerol-3-phosphate via glyceroneogenesis contributes to regulating triglyceride accumulation in white adipose tissue in women.

Strongylocentrotus intermedius Extract Suppresses Adiposity by Inhibiting Adipogenesis and Promoting Adipocyte Browning via AMPK Activation in 3T3-L1 Cells.

The current study aimed to determine whether Strongylocentrotus intermedius (S. intermedius) extract (SIE) exerts anti-obesity potentials employing 3T3-L1 cells as in vitro model. Herein we reported that treatment of SIE for 6 days reduced lipid accretion and triglyceride content whereas it increased the release of free glycerol. The inhibited lipid accumulation and induced lipolysis were evidenced by the downregulation of lipogenesis proteins, such as fatty acid synthase and lipoprotein lipase, and the upregulation of hormone-sensitive lipase expression. Furthermore, the downregulation of adipogenic transcription factors, including peroxisome proliferator-activated receptor gamma, CCAAT/enhancer-binding protein α, and sterol regulatory element-binding protein 1, highlights that reduced lipid accumulation is supported by lowering adipocyte differentiation. Additionally, treatment activates brown adipocyte phenotype in 3T3-L1 cells by inducing expression of brown adipose tissue-specific proteins, such as uncoupling protein 1 and peroxisome proliferator-activated receptor-γ coactivator 1α. Moreover, SIE induced the phosphorylation of AMP-activated protein kinase (AMPK). The pharmacological approach using AMPK inhibitor revealed that the restraining effect of SIE on adipogenesis and promotion of adipocyte browning were blocked. In GC-MS analysis, SIE was mainly composed of cholest-5-en-3-ol (36.71%) along with saturated and unsaturated fatty acids which have favorable anti-obesity potentials. These results reveal that SIE has the possibility as a lipid-lowering agent for the intervention of obesity.

Dietary phosphorus requirement of bullfrog Aquaranacatesbeiana

This experiment investigated the dietary phosphorus (P) requirement of bullfrogs Aquaranacatesbeiana. Six diets containing available P (AP) levels of 0.29% (the control group), 0.47%, 0.65%, 0.88%, 1.06% and 1.24% were formulated and fed to bullfrogs for 56 days. As dietary AP level increased from 0.29% to 1.24%, weight gain rate increased and then decreased, reaching the highest at the AP level of 0.88% (P < 0.05). Compared to the control group, content of crude protein in the whole-body was significantly increased in bullfrogs fed the 0.88% AP diet (P < 0.05). Content of crude lipid in the whole-body was significantly decreased in bullfrogs fed the 0.65%, 0.88%, 1.06% and 1.24% AP diets compared to those fed the 0.29% and 0.47% AP diets (P < 0.05). Bullfrogs fed the 0.65%, 0.88%, 1.06%, and 1.24% AP diets had higher content of serum P than those fed the 0.29% and 0.47% AP diets (P < 0.05). Activity of glutamic pyruvic transaminase in the serum was significantly decreased in bullfrogs fed the 0.88%, 1.06% and 1.24% AP diets compared to those fed the 0.29% and 0.47% AP diets (P < 0.05). Bullfrogs fed the 0.65%, 0.88%, 1.06% and 1.24% AP diets had lower contents of total cholesterol in the liver and triglycerides in the serum than the control group (P < 0.05). Meanwhile, bullfrogs fed the 0.47%, 0.65%, 0.88% and 1.06% AP diets had higher total antioxidant capacity in the serum than the control group (P < 0.05). Compared to the control group, contents of P and calcium in the whole-body were significantly increased in bullfrogs fed the 0.65%, 0.88%, 1.06% and 1.24% AP diets (P < 0.05). Compared to the control group, bullfrogs fed the 0.88%, 1.06% and 1.24% AP diets had lower expression of sodium-dependent phosphate transporter in the intestine and kidney, and higher expression of hormone-sensitive triglyceride lipase in the liver (P < 0.05). Bullfrogs fed the 0.88% and 1.06% AP diets had higher the mucosal fold height than those fed the 0.29% and 1.24% AP diets (P < 0.05). Compared to those fed the 0.29% and 1.24% AP diets, the abundance of potentially pathogenic bacteria Serratia and Acinetobacter in the intestine was decreased in bullfrogs fed the 0.88% AP diet. Using the weight gain rate, feed efficiency, whole-body and serum P content as evaluation indicators, the AP requirements of bullfrogs was 0.82% to 0.89%.

Mulberry Leaf Dietary Supplementation Can Improve the Lipo-Nutritional Quality of Pork and Regulate Gut Microbiota in Pigs: A Comprehensive Multi-Omics Analysis.

Mulberry leaves, a common traditional Chinese medicine, represent a potential nutritional strategy to improve the fat profile, also known as the lipo-nutrition, of pork. However, the effects of mulberry leaves on pork lipo-nutrition and the microorganisms and metabolites in the porcine gut remain unclear. In this study, multi-omics analysis was employed in a Yuxi black pig animal model to explore the possible regulatory mechanism of mulberry leaves on pork quality. Sixty Yuxi black pigs were divided into two groups: the control group (n = 15) was fed a standard diet, and the experimental group (n = 45) was fed a diet supplemented with 8% mulberry leaves. Experiments were performed in three replicates (n = 15 per replicate); the two diets were ensured to be nutritionally balanced, and the feeding period was 120 days. The results showed that pigs receiving the diet supplemented with mulberry leaves had significantly reduced backfat thickness (p < 0.05) and increased intramuscular fat (IMF) content (p < 0.05) compared with pigs receiving the standard diet. Lipidomics analysis showed that mulberry leaves improved the lipid profile composition and increased the proportion of triglycerides (TGs). Interestingly, the IMF content was positively correlated with acyl C18:2 and negatively correlated with C18:1 of differential TGs. In addition, the cecal microbiological analysis showed that mulberry leaves could increase the abundance of bacteria such as UCG-005, Muribaculaceae_norank, Prevotellaceae_NK3B31_group, and Limosilactobacillus. Simultaneously, the relative levels of L-tyrosine-ethyl ester, oleic acid methyl ester, 21-deoxycortisol, N-acetyldihydrosphingosine, and mulberrin were increased. Furthermore, we found that mulberry leaf supplementation significantly increased the mRNA expression of lipoprotein lipase, fatty acid-binding protein 4, and peroxisome proliferators-activated receptor γ in muscle (p < 0.01). Mulberry leaf supplementation significantly increased the mRNA expression of diacylglycerol acyltransferase 1 (p < 0.05) while significantly decreasing the expression of acetyl CoA carboxylase in backfat (p < 0.05). Furthermore, mulberry leaf supplementation significantly upregulated the mRNA expression of hormone-sensitive triglyceride lipase and peroxisome proliferator-activated receptor α (p < 0.05) in backfat. In addition, mulberry leaf supplementation led to increased serum leptin and adiponectin (p < 0.01). Collectively, this omic profile is consistent with an increased ratio of IMF to backfat in the pig model.

Human recombinant relaxin-2 (serelaxin) regulates the proteome, lipidome, lipid metabolism and inflammatory profile of rat visceral adipose tissue

Recombinant human relaxin-2 (serelaxin) has been widely proven as a novel drug with myriad effects at different cardiovascular levels, which support its potential therapeutic efficacy in several cardiovascular diseases (CVD). Considering these effects, together with the influence of relaxin-2 on adipocyte physiology and adipokine secretion, and the connection between visceral adipose tissue (VAT) dysfunction and the development of CVD, we could hypothesize that relaxin-2 may regulate VAT metabolism. Our objective was to evaluate the impact of a 2-week serelaxin treatment on the proteome and lipidome of VAT from Sprague-Dawley rats. We found that serelaxin increased 1 polyunsaturated fatty acid and 6 lysophosphatidylcholines and decreased 4 triglycerides in VAT employing ultra-high performance liquid chromatography-mass spectrometry (UHPLC-MS) based platforms, and that regulates 47 phosphoproteins using SWATH/MS analysis. Through RT-PCR, we found that serelaxin treatment also caused an effect on VAT lipolysis through an increase in the mRNA expression of hormone-sensitive lipase (HSL) and a decrease in the expression of adipose triglyceride lipase (ATGL), together with a reduction in the VAT expression of the fatty acid transporter cluster of differentiation 36 (Cd36). Serelaxin also caused an anti-inflammatory effect in VAT by the decrease in the mRNA expression of tumor necrosis factor α (TNFα), interleukin-1β (IL-1β), chemerin, and its receptor. In conclusion, our results highlight the regulatory role of serelaxin in the VAT proteome and lipidome, lipolytic function, and inflammatory profile, suggesting the implication of several mechanisms supporting the potential benefit of serelaxin for the prevention of obesity and metabolic disorders.

Metformin improves obesity-related oligoasthenospermia via regulating the expression of HSL in testis in mice

Researches have proposed that obesity might contribute to development of oligoasthenospermia. This study was performed to confirm whether obesity contributes to oligoasthenospermia as well as the underlying mechanisms in mice fed with a high fat diet (HFD). Meanwhile, the actions of metformin, a drug of well-known weight-lowering effect, on sperm quality in obese mice were investigated. Our results showed that HFD feeding reduced sperm quality and steroid hormone levels in mice, associated with disruptions in testicular histomorphology and spermatogenesis. Moreover, obesity increased sperm apoptosis. These effects could be prevented by metformin treatment in HFD-fed mice. Mechanistically, an increasement in lipid contents associated with decreased hormone-sensitive lipase (HSL) protein expression in testes in HFD-fed mice was observed, which could be improved by metformin treatment. Then, the model of TM4 mouse Sertoli cells stimulated with palmitic acid (PA) was used to investigate the potential effect of lipid retention on testicular apoptosis and sperm quality reduction. In consistent, PA exposure elevated lipid contents as well as apoptosis in TM4 cells, which could also be improved by metformin treatment. Of note, the protein expression of HSL was reduced stimulated by PA in TM4 cells, also rescued by metformin. Then, anti-apoptosis effect of metformin would be lost with the deficiency of HSL. In summary, our study propose that obesity contributes to oligoasthenospermia by increasing sperm apoptosis induced by impaired lipid hydrolysis due to HSL down-regulation, which could be prevented with metformin treatment via regulating the expression of HSL in testis in mice.

Effect of His Bundle Pacing on Abnormal Myocardial Fatty Acid and Glucose Metabolism Induced by Right Ventricular Pacing.

Metabolic disorder is noted for pacing-induced cardiomyopathy. The benefits of His bundle pacing over right ventricular (RV) pacing in preventing pacing-induced cardiomyopathy from a metabolic perspective are yet to be fully understood. Three pig groups were established for this study: sham control, RV pacing (RV pacing for 6 months), and His pacing (RV pacing for 6 months, followed by His bundle pacing for 3 months). Complete atrioventricular block was created in the last 2 groups. Left ventricular function and dyssynchrony were assessed via echocardiography, while proteins linked to metabolism, endoplasmic reticulum stress, and inflammation in left ventricular myocardium were examined. The RV pacing group had significantly more left ventricular mechanical dyssynchrony compared with the other groups. The RV pacing group exhibited triglyceride and diacylglycerol accumulation in cardiomyocytes and higher expression of binding immunoglobulin protein and tumor necrosis factor-α than the other groups. Additionally, the expression of CD36 was activated, while the expression of hormone-sensitive lipase was downregulated in the RV pacing group compared with the His pacing and sham control groups. Furthermore, the expressions of GLUT4 and pyruvate dehydrogenase were higher in the RV pacing group than the sham control and His pacing groups. Notably, the abnormal fatty acid and glucose metabolic pathways in the left ventricular myocardium during RV pacing could be corrected by His bundle pacing. His bundle pacing can mitigate the abnormal metabolism disorders, endoplasmic reticulum stress, and inflammation induced during RV pacing and may contribute to the superiority of conduction system pacing over RV pacing in reducing heart failure hospitalization.

Sex-Specific Effects of Long-Term Antipsychotic Drug Treatment on Adipocyte Tissue and the Crosstalk to Liver and Brain in Rats.

Antipsychotic drug (APD) medication can lead to metabolic dysfunctions and weight gain, which together increase morbidity and mortality. Metabolically active visceral adipose tissue (VAT) in particular plays a crucial role in the etiopathology of these metabolic dysregulations. Here, we studied the effect of 12 weeks of drug medication by daily oral feeding of clozapine and haloperidol on the perirenal fat tissue as part of VAT of male and female Sprague Dawley rats in the context of complex former investigations on brain, liver, and blood. Adipocyte area values were determined, as well as triglycerides, non-esterified fatty acids (NEFAs), glucose, glycogen, lactate, malondialdehyde equivalents, ferric iron and protein levels of Perilipin-A, hormone-sensitive-lipase (HSL), hepcidin, glucose transporter-4 (Glut-4) and insulin receptor-ß (IR-ß). We found increased adipocyte mass in males, with slightly higher adipocyte area values in both males and females under clozapine treatment. Triglycerides, NEFAs, glucose and oxidative stress in the medicated groups were unchanged or slightly decreased. In contrast to controls and haloperidol-medicated rats, perirenal adipocyte mass and serum leptin levels were not correlated under clozapine. Protein expressions of perilipin-A, Glut-4 and HSL were decreased under clozapine treatment. IR-ß expression changed sex-specifically in the clozapine-medicated groups associated with higher hepcidin levels in the perirenal adipose tissue of clozapine-treated females. Taken together, clozapine and haloperidol had a smaller effect than expected on perirenal adipose tissue. The perirenal adipose tissue shows only weak changes in lipid and glucose metabolism. The main changes can be seen in the proteins examined, and probably in their effect on liver metabolism.

Hsa_circ_0021205 enhances lipolysis via regulating miR-195-5p/HSL axis and drives malignant progression of glioblastoma

Abnormal lipid metabolism is an essential hallmark of glioblastoma. Hormone sensitive lipase (HSL), an important rate-limiting enzyme contributed to lipolysis, which was involved in aberrant lipolysis of glioblastoma, however, its definite roles and the relevant regulatory pathway have not been fully elucidated. Our investigations disclosed high expression of HSL in glioblastoma. Knock-down of HSL restrained proliferation, migration, and invasion of glioblastoma cells while adding to FAs could significantly rescue the inhibitory effect of si-HSL on tumor cells. Overexpression of HSL further promoted tumor cell proliferation and invasion. Bioinformatics analysis and dual-luciferase reporter assay were performed to predict and verify the regulatory role of ncRNAs on HSL. Mechanistically, hsa_circ_0021205 regulated HSL expression by sponging miR-195-5p, which further promoted lipolysis and drove the malignant progression of glioblastoma. Besides, hsa_circ_0021205/miR-195-5p/HSL axis activated the epithelial-mesenchymal transition (EMT) signaling pathway. These findings suggested that hsa_circ_0021205 promoted tumorigenesis of glioblastoma through regulation of HSL, and targeting hsa_circ_0021205/miR-195-5p/HSL axis can serve as a promising new strategy against glioblastoma.

Two Triterpenoids, ARM-2 and RA-5, From Protorhus longifolia Exhibit the Potential to Modulate Lipolysis and Lipogenesis in Cultured 3T3-L1 Adipocytes.

Triterpenoids have been identified as potential novel lipid-lowering drugs for the treatment of hypertriglyceridemia. This study investigated the potential antilipogenic and/or antilipolytic effects of two triterpenoids (ARM-2 and RA-5) isolated from the stem bark of Protorhus longifolia (Benrh.) Engl. Employing a combination of in silico predictions and in vitro assays, the interactions between these triterpenoids and key proteins involved in lipogenesis and lipolysis were investigated. In silico molecular docking analysis predicted a favourable binding affinity of both triterpenoids to PPARγ, SREBP-1, and AMPK, with lower binding affinity to C/EBPα, pancreatic lipase, and hormone-sensitive lipase (HSL). Both triterpenoids exhibited in vitro inhibition of pancreatic lipase with Ki and IC50 values ranging from 28.7 to 52.9 μM and 27.6 to 35.8 μM, respectively. Total and neutral lipid accumulation in differentiated 3T3-L1 adipocytes and the oleic acid-induced HepG2 cell model was inhibited, with ARM-2 showing better inhibition than RA-5. In the HepG2 model, the inhibitory activity of the two triterpenoids (at 25 and 100 μM) was comparable to 50 μM lovastatin, although the latter was cytotoxic, whereas both ARM-2 and RA-2 lacked cytotoxicity. Associated gene expression was similar to the effect of simvastatin where the expression of SREBP-1, PPARγ, C/EBPα, and HSL was reduced and that of AMPK was unchanged. In vitro studies confirmed that ARM-2 and RA-5 also inhibited adipocyte lipolysis, where the reduction in glycerol release by 25 and 100 μM was similar to 50 μM lovastatin and simvastatin. This study identifies that the triterpenoids, ARM-2 and RA-5, have the potential to modulate lipogenesis and lipolysis.

Design and Synthesis of Novel Indole Ethylamine Derivatives as a Lipid Metabolism Regulator Targeting PPARα/CPT1 in AML12 Cells.

Peroxisome proliferator-activated receptor alpha (PPARα) and carnitine palmitoyltransferase 1 (CPT1) are important targets of lipid metabolism regulation for nonalcoholic fatty liver disease (NAFLD) therapy. In the present study, a set of novel indole ethylamine derivatives (4, 5, 8, 9) were designed and synthesized. The target product (compound 9) can effectively activate PPARα and CPT1a. Consistently, in vitro assays demonstrated its impact on the lipid accumulation of oleic acid (OA)-induced AML12 cells. Compared with AML12 cells treated only with OA, supplementation with 5, 10, and 20 μM of compound 9 reduced the levels of intracellular triglyceride (by 28.07%, 37.55%, and 51.33%) with greater inhibitory activity relative to the commercial PPARα agonist fenofibrate. Moreover, the compound 9 supplementations upregulated the expression of hormone-sensitive triglyceride lipase (HSL) and adipose triglyceride lipase (ATGL) and upregulated the phosphorylation of acetyl-CoA carboxylase (ACC) related to fatty acid oxidation and lipogenesis. This dual-target compound with lipid metabolism regulatory efficacy may represent a promising type of drug lead for NAFLD therapy.

Extracellular macrophage migration inhibitory factor (MIF) downregulates adipose hormone-sensitive lipase (HSL) and contributes to obesity

Attenuation of adipose hormone sensitive lipase (HSL) may impair lipolysis and exacerbate obesity. We investigate the role of cytokine, macrophage migration inhibitory factor (MIF) in regulating adipose HSL and adipocyte hypertrophy. Extracellular MIF downregulates HSL in an autocrine fashion, by activating the AMPK/JNK signaling pathway upon binding to its membrane receptor, CD74. WT mice fed high fat diet (HFD), as well as mice overexpressing MIF, both had high circulating MIF levels and showed suppression of HSL during the development of obesity. Blocking the extracellular action of MIF by a neutralizing MIF antibody significantly reduced obesity in HFD mice. Interestingly, intracellular MIF binds with COP9 signalosome subunit 5 (Csn5) and JNK, which leads to an opposing effect to inhibit JNK phosphorylation. With global MIF deletion, adipocyte JNK phosphorylation increased, resulting in decreased HSL expression, suggesting that the loss of MIF's intracellular inhibitory action on JNK was dominant in Mif−/− mice. Adipose tissue from Mif−/− mice also exhibited higher Akt and lower PKA phosphorylation following HFD feeding compared with WT, which may contribute to the downregulation of HSL activation during more severe obesity. Both intracellular and extracellular MIF have opposing effects to regulate HSL, but extracellular actions predominate to downregulate HSL and exacerbate the development of obesity during HFD.

THU507 Tumor Activin A Mediates Cachexia Primarily Through White Adipose Tissue Hydrolysis In Pancreatic Ductal Adenocarcinoma

Abstract Disclosure: S. Yu: None. Y. Luan: None. R. Dong: None. A. Abazarikia: None. S. Kim: None. Pancreatic ductal adenocarcinoma (PDAC) commonly harbors mutations in KRAS and TP53 genes and its overall 5-year survival rate is only 10% in the US. Among risk factors associated with the dismal PDAC prognosis, cachexia accounts for about 30% of PDAC-related death and is present in nearly 80% of PDAC patients. Significant adipose tissue loss followed by skeletal muscle loss characterizes PDAC-related cachexia in humans and mice. Accumulated evidence indicates that activin A, a homodimer of inhibin βA that is encoded by the INHBA gene, is a recognized key cachexia mediator as supported by mitigation of weight loss by activin A antagonists in PDAC-bearing mice. However, much remains unclear regarding the primary source cells of activin A and the mechanisms by which activin A mediates cachexia in PDAC. To address the unknowns, we employed CRISPR/Cas9 system for Inhba gene knock-down (KD) in mouse KPC (KrasG12D and Trp53R172H) PDAC cells and generated orthotopic mice using Inhba KD or control KPC cells. Sham group which received the same operation except for cell injection was included. Body weight was measured on a daily basis, and blood and white adipose tissues (WATs) and skeletal muscle tissues were harvested on post-surgery day 12. We found that, when compared to the Sham group, injection of control KPC cells significantly elevated serum activin A levels up to 6 ng/mL and temporally decreased the average body weight in the orthotopic mice (Ctrl group), whereas Inhba gene KD significantly reduced serum activin A levels by ∼ 2 ng/mL and prevented weight loss in the orthotopic mice (KD group). When compared to the Sham and KD groups, notable reductions in organ weights of epididymal, mesenteric or subcutaneous WATs were found in the Ctrl group, however, weights for gastrocnemius and plantaris or soleus muscle tissues were statistically similar between the Ctrl and KD groups at post-surgery day 12. Correspondingly, the average serum free fatty acids levels were higher in the Ctrl group than the KD group. Histological observations support that dramatic adipocyte size reductions in WATs were prevented by serum activin A suppression. Immunofluorescence analysis showed that WATs from the Ctrl group had considerably higher protein expression of hormone-sensitive or adipose triglyceride lipase than the KD and Sham groups. Furthermore, phosphorylation of SMAD3 and phosphorylated PKA substrate which regulate adipocyte lipolysis were intensely stained in WATs from the Ctrl group when compared to the KD and Sham groups. Collectively, our findings identify PDAC cancer cells as the major source of activin A in PDAC and suggest systemic activin A as a potential mediator of PDAC-related adipose tissue loss. The current findings warrant further investigation to address clinical relevance. Presentation: Thursday, June 15, 2023

Adipose Tissue Protects against Hepatic Steatosis in Male Rats Fed a High-Fat Diet plus Liquid Fructose: Sex-Related Differences.

Non-alcoholic fatty liver disease is a sexual dimorphic disease, with adipose tissue playing an essential role. Our previous work showed that female rats fed a high-fat high-fructose diet devoid of cholesterol (HFHFr) developed simple hepatic steatosis dissociated from obesity. This study assessed the impact of the HFHFr diet on the male rat metabolism compared with data obtained for female rats. A total of 16 Sprague Dawley (SD) male rats were fed either a control (standard rodent chow and water) or HFHFr (high-fat diet devoid of cholesterol, plus 10% fructose in drinking water) diet for 3 months. Unlike female rats, and despite similar increases in energy consumption, HFHFr males showed increased adiposity and hyperleptinemia. The expression of hormone-sensitive lipase in the subcutaneous white adipose tissue was enhanced, leading to high free fatty acid and glycerol serum levels. HFHFr males presented hypertriglyceridemia, but not hepatic steatosis, partially due to enhanced liver PPARα-related fatty acid β-oxidation and the VLDL-promoting effect of leptin. In conclusion, the SD rats showed a sex-related dimorphic response to the HFHFr diet. Contrary to previous results for HFHFr female rats, the male rats were able to expand the adipose tissue, increase fatty acid catabolism, or export it as VLDL, avoiding liver lipid deposition.

Social isolation increases metabolic rate in the transition of light- to dark- phase and advances Rev-erb-α expression in brown adipose tissue to regulate daily rhythm of core body temperature in mice

Mammals use social thermoregulation to maintain the core body temperature (Tc) at a lower energy cost. Brown adipose tissue (BAT) plays a crucial role in thermoregulation. This study tested the hypothesis that social isolation induces alterations in thermogenesis and metabolism to maintain the rhythm of Tc throughout the day. Adult male mice (C57BLJ/6) were maintained in groups of 4–5 (group-housed) or isolated (single-housed) for 28 days. Telemetric probes recorded spontaneous locomotor activity (SLA) and Tc to analyze SLA and Tc daily rhythms. Body weight was measured weekly. VO2 consumption was analyzed at zeitgeber time (ZT) 1–3 (beginning of light phase) or ZT10–14 (beginning of dark phase). The expression of thermogenic-related and clock genes in the BAT occurred at ZT2, ZT8, ZT14, and ZT20. The β3 adrenergic agonist CL-316,243 was i.p. injected in the group- or single-housed mice. Social isolation increased the amplitude of Tc rhythm but decreased the amplitude of SLA oscillation. Nevertheless, in single-housed mice, the circadian peak of Tc and SLA was unaltered, with reduced body weight gain, increased VO2 consumption, and BAT Ucp1 expression at ZT14. Isolation advanced the BAT Rev-erb-ɑ peak of expression and phased-shift the peak of expression in BAT Bmal1, while it abolished the daily BAT Per2 oscillation. Isolation also abolished the BAT Ucp1 and hormone-sensitive lipase (Hsl) expression induced by stimulation of the β3ADR, but it increased Rev-erb-ɑ and Pgc1α. Thus, alterations in Ucp1, Reverb-α, Bmal1, and Per2 daily expression may favor an increased metabolic rate at the beginning of the dark, which, in turn, contributes to maintaining the daily Tc rhythm at the expense of reduced body weight gain in isolated mice. In addition, at least at the transcription level, the response of BAT from isolated mice to adrenergic agonist seems to be via a non-canonical mechanism involving Rev-erb-α and Pgc1α.

Decapentaplegic retards lipolysis during metamorphosis in Bombyx mori and Drosophila melanogaster.

Insect morphogen decapentaplegic (Dpp) functions as one of the key extracellular ligands of the Bone Morphogenetic Protein (BMP) signaling pathway. Previous studies in insects mainly focused on the roles of Dpp during embryonic development and the formation of adult wings. In this study, we demonstrate a new role for Dpp in retarding lipolysis during metamorphosis in both Bombyx mori and Drosophila melanogaster. CRISPR/Cas9-mediated mutation of Bombyx dpp causes pupal lethality, induces an excessive and premature breakdown of lipids in the fat body, and upregulates the expressions of several lipolytic enzyme genes, including brummer (bmm), lipase 3 (lip3), and hormone-sensitive lipase (hsl), and lipid storage droplet 1 (lsd1), a lipid droplets (LD)-associated protein gene. Further investigation in Drosophila reveals that salivary gland-specific knockdown of the dpp gene and fat body-specific knockdown of Mad involved in Dpp signaling phenocopy the effects of Bombyx dpp mutation on pupal development and lipolysis. Taken together, our data indicate that the Dpp-mediated BMP signaling in the fat body maintains lipid homeostasis by retarding lipolysis, which is necessary for pupa-adult transition during insect metamorphosis.

The lipidomic and inflammatory profiles of visceral and subcutaneous adipose tissues are distinctly regulated by the SGLT2 inhibitor empagliflozin in Zucker diabetic fatty rats

The pharmacological inhibition of sodium-glucose cotransporter 2 (SGLT2) has emerged as a treatment for patients with type 2 diabetes mellitus (T2DM), cardiovascular disease and/or other metabolic disturbances, although some of the mechanisms implicated in their beneficial effects are unknown. The SGLT2 inhibitor (SGLT2i) empagliflozin has been suggested as a regulator of adiposity, energy metabolism, and systemic inflammation in adipose tissue. The aim of our study was to evaluate the impact of a 6-week-empagliflozin treatment on the lipidome of visceral (VAT) and subcutaneous adipose tissue (SAT) from diabetic obese Zucker Diabetic Fatty (ZDF) rats using an untargeted metabolomics approach. We found that empagliflozin increases the content of diglycerides and oxidized fatty acids (FA) in VAT, while in SAT, it decreases the levels of several lysophospholipids and increases 2 phosphatidylcholines. Empagliflozin also reduces the expression of the cytokines interleukin-1 beta (IL-1β), IL-6, tumor necrosis factor-alpha (TNFα), monocyte-chemotactic protein-1 (MCP-1) and IL-10, and of Cd86 and Cd163 M1 and M2 macrophage markers in VAT, with no changes in SAT, except for a decrease in IL-1β. Empagliflozin treatment also shows an effect on lipolysis increasing the expression of hormone-sensitive lipase (HSL) in SAT and VAT and of adipose triglyceride lipase (ATGL) in VAT, together with a decrease in the adipose content of the FA transporter cluster of differentiation 36 (CD36). In conclusion, our data highlighted differences in the VAT and SAT lipidomes, inflammatory profiles and lipolytic function, which suggest a distinct metabolism of these two white adipose tissue depots after the empagliflozin treatment.