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Lipid droplets (LD) are triglyceride storing organelles that have emerged as an important component of cellular inflammatory responses. LD lipolysis via adipose triglyceride lipase (ATGL), the enzyme that catalyses the rate-limiting step of triglyceride lipolysis, regulates inflammation in peripheral immune and non-immune cells. ATGL elicits both pro- and anti-inflammatory responses in the periphery in a cell-type dependent manner. The present study determined the impact of ATGL inhibition and microglia-specific ATGL genetic loss-of-function on acute inflammatory and behavioural responses to pro-inflammatory insult. First, we evaluated the impact of lipolysis inhibition on lipopolysaccharide (LPS)-induced expression and secretion of cytokines and phagocytosis in mouse primary microglia cultures. Lipase inhibitors (ORlistat and ATGListatin) and LPS led to LD accumulation in microglia. Pan-lipase inhibition with ORlistat alleviated LPS-induced expression of IL-1β and IL-6. Specific inhibition of ATGL had a similar action on CCL2, IL-1β and IL-6 expression in both neonatal and adult microglia cultures. CCL2 and IL-6 secretion were also reduced by ATGListatin or knockdown of ATGL. ATGListatin increased phagocytosis in neonatal cultures independently from LPS treatment. Second, targeted and untargeted lipid profiling revealed that ATGListatin reduced LPS-induced generation of pro-inflammatory prostanoids and modulated ceramide species in neonatal microglia. Finally, the role of microglial ATGL in neuroinflammation was assessed using a novel microglia-specific and inducible ATGL knockout mouse model. Loss of microglial ATGL in adult male mice dampened LPS-induced expression of IL-6 and IL-1β and microglial density. LPS-induced sickness- and anxiety-like behaviours were also reduced in male mice with loss of ATGL in microglia. Together, our results demonstrate potent anti-inflammatory effects produced by pharmacological or genetic inhibition of ATGL-mediated triglyceride lipolysis and thereby propose that supressing microglial LD lipolysis has beneficial actions in acute neuroinflammatory conditions., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

During the past years, several drugs have been developed for the treatment of obesity. Some are already used in clinical practice: orlistat, GLP-1 receptor agonists (RA), GLP-1/GIP biagonists and the melanocortin 4 receptor (MC4R) agonist, setmelanotide. Some should be available in the future: GLP-1/glucagon biagonists, GLP-1/GIP/glucagon triagonists. These drugs act mainly by reducing food intake or fat absorption. However, many of them show specific effects on the adipose tissue. All these drugs show significant reduction of fat mass and, more particularly of visceral fat. If most of the drugs, except orlistat, have been shown to increase energy expenditure in rodents with enhanced thermogenesis, this has not yet been clearly demonstrated in humans. However, biagonists or triagonist stimulating glucagon seem to a have a more potent effect to increase thermogenesis in the adipose tissue and, thus, energy expenditure. Most of these drugs have been shown to increase the production of adiponectin and to reduce the production of pro-inflammatory cytokines by the adipose tissue. GLP-1RAs reduce the size of adipocytes and promote their differentiation. GLP-1RAS and GLP-1/GIP biagonists reduce, in the adipose tissue, the expression of several genes involved in lipogenesis. Further studies are still needed to clarify the precise roles, on the adipose tissue, of these drugs dedicated for the treatment of obesity., (Copyright © 2024 The Author. Published by Elsevier Masson SAS.. All rights reserved.)

Orlistat, an anti-obesity agent, inhibits the metabolism and absorption of dietary fat by inactivating pancreatic lipase in the gut. The effect of orlistat on the gut microbiota of Japanese individuals with obesity is unknown. This study aimed to explore the effects of orlistat on the gut microbiota and fatty acid metabolism of Japanese individuals with obesity. Fourteen subjects with visceral fat obesity (waist circumference ≥85 cm) took orlistat orally at a dose of 60 mg, 3 times a day for 8 weeks. Body weight; waist circumference; visceral fat area; levels of short-chain fatty acids, gut microbiota, fatty acid metabolites in the feces, and gastrointestinal hormones; and adverse events were evaluated. Body weight, waist circumference, and blood leptin concentrations were significantly lower after orlistat treatment (mean ± standard deviation, 77.8 ± 9.1 kg; 91.9 ± 8.7 cm; and 4546 ± 3211 pg/mL, respectively) compared with before treatment (79.4 ± 9.0 kg; 94.4 ± 8.0 cm; and 5881 ± 3526 pg/mL, respectively). Significant increases in fecal levels of fatty acid metabolites (10-hydroxy-cis-12-octadecenoic acid, 10-oxo-cis-12-octadecenoic acid, and 10-oxo-trans-11-octadecenoic acid) were detected. Meanwhile, no significant changes were found in abdominal computed tomography parameters, blood marker levels, or short-chain fatty acid levels in the feces. Gut microbiota analysis revealed that some study subjects had decreased abundance of Firmicutes, increased abundance of Bacteroidetes, and increased α-diversity indices (Chao1 and ACE) after 8 weeks of treatment. The levels of Lactobacillus genus and Lactobacillus gasseri were significantly higher after 8 weeks of treatment. None of the subjects discontinued treatment or experienced severe adverse events. This study suggested that orlistat might alter gut microbiota composition and affect the body through fatty acid metabolites produced by the modified gut bacteria., Competing Interests: Declaration of Competing Interest All investigators in this study declared Conflict of No Interest., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Obesity is an abnormal fat accumulation disorder in the metabolic syndrome constellation, and a risk factor for diabetes, cardiovascular disorders, non-alcoholic fatty liver disease (NAFLD), and cancer. Nuclear receptors (Peroxisome proliferator-activated receptor, PPAR) are implicated in metabolic syndrome and NAFLD, and have potential for therapeutic targeting. Nuclear receptors are ligand-dependent transcription factors that have diverse roles in metabolism, including regulating genes involved in lipid and glucose metabolism, modulating inflammatory genes, and are crucial for maintaining metabolic flexibility. PPAR activates adipose triglyceride lipase, which then releases fatty acids as ligands for PPAR, indicating the interdependency of nuclear receptors and lipases. Here, molecular docking was performed with selected phytochemical ligands that can bind with PPAR-α/γ (PDB ID: 2ZNN and 2ATH, respectively) using Glide module of Schrodinger software followed by molecular dynamics simulation study using Desmond module, and ADMET analysis. Interestingly, orlistat which is a well-known lipase and fatty acid synthase inhibitor also demonstrated favorable binding affinity with both PPAR-α/γ (-10.96 kcal/mol against PPARα and -10.26 kcal/mol against PPARγ). The highest docking scores were however shown by the flavonoids - rutin (-14.88 kcal/mol against PPARα and -13.64 kcal/mol against PPARγ), and its aglycone, quercetin (-10.08 kcal/mol in PPARα and -9.89 kcal/mol in PPARγ). The other phytochemicals (genistein, esculin, daidzin, naringenin, daidzein, dihydroxy coumarin, hydroquinone) showed lower binding affinity as dual agonists. The anti-obesity effects were experimentally validated in cultured adipocytes, which revealed better lipid inhibition by rutin and quercetin than orlistat (quercetin > rutin > orlistat) pointing to their strong potential in anti-obesity treatment., (Copyright © 2022. Published by Elsevier Ltd.)

Breast cancer stem cells (CSCs) are distinct CD44 + -subpopulations that are involved in metastasis and chemoresistance. However, the underlying molecular mechanism of CD44 in breast CSCs-mediated tumorigenesis remains elusive. We observed high CD44 expression in advanced-stage clinical breast tumor samples. CD44 activation in breast CSCs sorted from various triple negative breast cancer (TNBC) cell lines induced proliferation, migration, invasion, mammosphere formation that were reversed in presence of inhibitor, 4-methyl umbelliferone or CD44 silencing. CD44 activation in breast CSCs induced Src, Akt, and nuclear translocation of pSTAT3. PCR arrays revealed differential expression of a metabolic gene, Lipoprotein lipase (LPL), and transcription factor, SNAI3. Differential transcriptional regulation of LPL by pSTAT3 and SNAI3 was confirmed by promoter-reporter and chromatin immunoprecipitation analysis. Orthotopic xenograft murine breast tumor model revealed high tumorigenicity of CD24 - /CD44 + -breast CSCs as compared with CD24 + -breast cancer cells. Furthermore, stable breast CSCs-CD44 shRNA and/or intratumoral administration of Tetrahydrolipstatin (LPL inhibitor) abrogated tumor progression and neoangiogenesis. Thus, LPL serves as a potential target for an efficacious therapeutics against aggressive breast cancer., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Aim: Abiraterone acetate for metastatic castration-resistant prostate cancer is an acetylated prodrug to be hydrolyzed to abiraterone. Abiraterone acetate is known to be hydrolyzed by pancreatic cholesterol esterase secreted into the intestinal lumen. This study aimed to investigate the possibility that arylacetamide deacetylase (AADAC) expressed in enterocytes contributes to the hydrolysis of abiraterone acetate based on its substrate preference., Materials and Methods: Abiraterone acetate hydrolase activity was measured using human intestinal (HIM) and liver microsomes (HLM) as well as recombinant AADAC. Correlation analysis between activity and AADAC expression was performed in 14 individual HIMs. The in vivo pharmacokinetics of abiraterone acetate was examined using wild-type and Aadac knockout mice administered abiraterone acetate with or without orlistat, a pancreatic cholesterol esterase inhibitor., Key Findings: Recombinant AADAC showed abiraterone acetate hydrolase activity with similar K m value to HIM and HLM. The positive correlation between activity and AADAC levels in individual HIMs supported the responsibility of AADAC for abiraterone acetate hydrolysis. The area under the plasma concentration-time curve (AUC) of abiraterone after oral administration of abiraterone acetate in Aadac knockout mice was 38% lower than that in wild-type mice. The involvement of pancreatic cholesterol esterase in abiraterone formation was revealed by the decreased AUC of abiraterone by coadministration of orlistat. Orlistat potently inhibited AADAC, implying its potential as a perpetrator of drug-drug interactions., Significance: AADAC is responsible for the hydrolysis of abiraterone acetate in the intestine and liver, suggesting that concomitant use of abiraterone acetate and drugs potently inhibiting AADAC should be avoided., (Copyright © 2021 Elsevier Inc. All rights reserved.)

The burden of obesity is increasing all over the world. Except for Orlistat, no effective anti-obesity drug is currently available. Therefore, a search for the new anti-obesity compound is need of time. This study demonstrates macromolecular interaction and inhibitory effect of pentacyclic triterpenoids (PTT) on pancreatic lipase (PL). In the present study PTTs from endophytic Colletotrichum gigasporum were found to show significant inhibitory activity against PL with IC 50 of 16.62 ± 1.43 μg/mL. The PTT isolated through bioassay-guided isolation showed a dose-dependent (R 2  = 0.915) inhibition against porcine PL and the results were comparable with the standard (Orlistat). Based on inhibition kinetic data, the gradual increase in K m (app) with increasing PTT concentration indicated that the mode of interaction of PTT with PL was a competitive type, and it directly competed with the substrate (pNPB) for the active site of PL. In vivo studies in Wistar rats at the oral dose (100 mg/kg body weight) of PTT significantly decreased (p < 0.05) incremental plasma triglyceride levels as compared to group B and TG absorption was down-regulated up to 49.18% vis a vis group D animals. The isolated PTT was identified as lupeol based on chromatographic and spectral data. The endophytic isolate was identified as Colletotrichum gigasporum based on morphology and ITS gene sequencing. The present study indicated that PTT had the potential to be used as a natural PL inhibitor in the treatment of obesity and the isolated endophyte can be a valuable bioresource for it., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2021 Elsevier B.V. All rights reserved.)

The hydrolysis of triglycerides in triglyceride-rich lipoproteins by LPL is critical for the delivery of triglyceride-derived fatty acids to tissues, including heart, skeletal muscle, and adipose tissues. Physiologically active LPL is normally bound to the endothelial cell protein glycosylphosphatidylinositol-anchored high-density lipoprotein binding protein 1 (GPIHBP1), which transports LPL across endothelial cells, anchors LPL to the vascular wall, and stabilizes LPL activity. Disruption of LPL-GPIHBP1 binding significantly alters triglyceride metabolism and lipid partitioning. In this study, we modified the NanoLuc® Binary Technology split-luciferase system to develop a novel assay that monitors the binding of LPL to GPIHBP1 on endothelial cells in real time. We validated the specificity and sensitivity of the assay using endothelial lipase and a mutant version of LPL and found that this assay reliably and specifically detected the interaction between LPL and GPIHBP1. We then interrogated various endogenous and exogenous inhibitors of LPL-mediated lipolysis for their ability to disrupt the binding of LPL to GPIHBP1. We found that angiopoietin-like (ANGPTL)4 and ANGPTL3-ANGPTL8 complexes disrupted the interactions of LPL and GPIHBP1, whereas the exogenous LPL blockers we tested (tyloxapol, poloxamer-407, and tetrahydrolipstatin) did not. We also found that chylomicrons could dissociate LPL from GPIHBP1 and found evidence that this dissociation was mediated in part by the fatty acids produced by lipolysis. These results demonstrate the ability of this assay to monitor LPL-GPIHBP1 binding and to probe how various agents influence this important complex., (Copyright © 2020 Shetty et al.)

Pancreatic lipase (PNLIP) is a digestive enzyme that is a potential drug target for the treatment of obesity. A better understanding of its regulation mechanisms would facilitate the development of new therapeutics. Recent studies indicate that intestinal lipolysis by PNLIP is reduced by Angiopoietin-like protein 4 (ANGPTL4), whose N-terminal domain (nANGPTL4) is a known inactivator of lipoprotein lipase (LPL) in blood circulation and adipocytes. To elucidate the mechanism of PNLIP inhibition by ANGPTL4, we developed a novel approach, using isothermal titration calorimetry (ITC). The obtained results were compared with those of well-described inhibitors of PNLIP - ε-polylysine (EPL), (-)-epigallocatechin-3-gallate (EGCG) and tetrahydrolipstatin. We demonstrate that ITC allows to investigate PNLIP inhibition mechanisms in complex substrate emulsions and that the ITC-based assay is highly sensitive - the lowest concentration for quantification of PNLIP is 1.5 pM. Combining ITC with surface plasmon resonance and fluorescence measurements, we present evidence that ANGPTL4 is a lipid-binding protein that influences PNLIP activity through interactions with components of substrate emulsions (bile salts, phospholipids and triglycerides), and this promotes the aggregation of triglyceride emulsions similarly to the PNLIP inhibitors EPL and EGCG. In the absence of substrate emulsion, unlike in the case of LPL, ANGPTL4 did not induce the inactivation of PNLIP. Our data also prove that due to various interactions with components of substrate systems, the effect of a PNLIP inhibitor depends on whether its effect is measured in a complex substrate emulsion or in a simple substrate system., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Chikungunya virus (CHIKV) is a rapidly emerging mosquito-borne RNA virus that causes epidemics of debilitating disease in tropical and sub-tropical regions with autochtonous transmission in regions with temperate climate. Currently, there is no licensed vaccine or specific antiviral drug available against CHIKV infection. In this study, we examine the role, in the CHIKV viral cycle, of fatty acid synthase (FASN) and stearoyl-CoA desaturase (SCD1), two key lipogenic enzymes required for fatty acid production and early desaturation. We show that both enzymes and their upstream regulator PI3K are required for optimal CHIKV infection. We demonstrate that pharmacologic manipulation of FASN or SCD1 enzymatic activity by non-toxic concentrations of cerulenin or CAY10566 decreases CHIKV genome replication. Interestingly, a similar inhibitory effect was also obtained with Orlistat, an FDA-approved anti-obesity drug that targets FASN activity. These drugs were also effective against Mayaro virus (MAYV), an under-studied arthritogenic Old world Alphavirus endemic in South American countries with potential risk of emergence, urbanization and dispersion to other regions. Altogether, our results identify FASN and SCD1 as conserved druggable cofactors of Alphavirus genome replication and support the broad-spectrum activity of drugs targeting the host fatty acids metabolism., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Hepatitis B Virus (HBV) is a strictly hepatotropic pathogen which is very efficiently targeted to the liver and into its host cell, the hepatocyte. The sodium taurocholate co-transporting polypeptide (NTCP) has been identified as a key virus entry receptor, but the early steps in the virus life cycle are still only barely understood. Here, we investigated the effect of lipase inhibition and lipoprotein uptake on HBV infection using differentiated HepaRG cells and primary human hepatocytes. We found that an excess of triglyceride rich lipoprotein particles in vitro diminished HBV infection and a reduced hepatic virus uptake in vivo if apolipoprotein E is lacking indicating virus transport along with lipoproteins to target hepatocytes. Moreover, we showed that HBV infection of hepatocytes was inhibited by the broadly active lipase inhibitor orlistat, approved as a therapeutic agent which blocks neutral lipid hydrolysis activity. Orlistat treatment targets HBV infection at a post-entry step and inhibited HBV infection during virus inoculation strongly in a dose-dependent manner. In contrast, orlistat had no effect on HBV gene expression or replication or when added after HBV infection. Taken together, our data indicate that HBV connects to the hepatotropic lipoprotein metabolism and that inhibition of cellular hepatic lipase(s) may allow to target early steps of HBV infection., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Obesity and high blood pressure (BP) are strongly related and weight loss is mightily associated with a significant BP decrease. The aim of the present meta-analysis was to evaluate and quantify the BP decrease associated with orlistat use in randomized controlled trials. The search included PubMed-Medline, Scopus, Web of Science and Google Scholar databases by up to June 05, 2017, to identify randomized controlled trials investigating the impact of orlistat on blood pressure. Quantitative data synthesis was performed using a random-effects model, with weighed mean difference and 95% confidence interval as summary statistics. Meta-regression and leave-one-out sensitivity analyses were performed to assess the modifiers of treatment response. Our meta-analysis included 27 randomized controlled clinical trials which comprehended overall 8150 subjects (4419 in the orlistat group and 3731 in the control one). We observed a statistically significant decreasing effect of orlistat on both systolic BP (-1.15 mmHg [-2.11, -0.19]) and diastolic BP (-1.07 mmHg [-1.69, -0.45]), regardless of its dosage. Significant associations were found between changes in systolic BP and diastolic BP with treatment duration but not with corresponding baseline BP values. In conclusion, Orlistat use contributes weight loss associated decrease in BP in overweight and obese subjects., (Copyright © 2017 American Society of Hypertension. Published by Elsevier Inc. All rights reserved.)

Background: Obesity is a public health problem and a major risk factor for metabolic syndrome. This study was designed to assess the effectiveness of grape seed and skin extract (GSSE) and Xenical (Xe) on high fat diet (HFD)-induced obesity and brain lipotoxicity., Method: Rats were rendered obese and then treated either with vehicle (control) or GSSE (4g/kg bw) or Xe (1, 2, 4 or 8mg/kg bw) or (GSSE+Xe) and monitored for weight loss during 3 months. Animals were then sacrificed and their brain utilised for the evaluation of lipotoxicity-induced oxidative stress as well as the putative protection offered by GSSE and Xe treatment., Results: As expected HFD-induced body and adipose tissue weight gain, dyslipidemia, accumulation of lipid into the brain, a drop in adiponectin, increased oxidative stress and disruption of Mn, Ca 2+ and of related enzyme activities as glutamine synthetase and calpain. Xe alone exerted anti-obesity effect during the first 2 months and became inefficient thereafter. GSSE per se exhibited potent anti-obesity effect whereas the combination (GSSE+Xe), by acting in concert, was the most efficient against obesity and brain lipotoxicity. GSSE acted partially through its anti-oxidative properties, whereas Xe did not., Conclusion: Combining GSSE with Xe improved outcomes in body weight and fat reduction as well as in brain lipotoxicity., (Copyright © 2016 Asia Oceania Association for the Study of Obesity. Published by Elsevier Ltd. All rights reserved.)