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Biomolecules Dec 2020Since the lipid profile is altered by physical activity, the study of lipid metabolism is a remarkable element in understanding if and how physical activity affects the... (Review)
Review
Since the lipid profile is altered by physical activity, the study of lipid metabolism is a remarkable element in understanding if and how physical activity affects the health of both professional athletes and sedentary subjects. Although not fully defined, it has become clear that resistance exercise uses fat as an energy source. The fatty acid oxidation rate is the result of the following processes: (a) triglycerides lipolysis, most abundant in fat adipocytes and intramuscular triacylglycerol (IMTG) stores, (b) fatty acid transport from blood plasma to muscle sarcoplasm, (c) availability and hydrolysis rate of intramuscular triglycerides, and (d) transport of fatty acids through the mitochondrial membrane. In this review, we report some studies concerning the relationship between exercise and the aforementioned processes also in light of hormonal controls and molecular regulations within fat and skeletal muscle cells.
Topics: Adipose Tissue; Blood Glucose; Endocrine System; Exercise; Fatty Acids; Humans; Lipid Metabolism; Lipolysis; Mitochondrial Membranes; Muscle, Skeletal; Oxygen; Sterol Esterase; Temperature; Triglycerides
PubMed: 33371437
DOI: 10.3390/biom10121699 -
Cell Aug 2020Fatty acid binding proteins (FABPs) serve as intracellular chaperones for fatty acids and other hydrophobic ligands inside cells. Recent studies have demonstrated new...
Fatty acid binding proteins (FABPs) serve as intracellular chaperones for fatty acids and other hydrophobic ligands inside cells. Recent studies have demonstrated new functions of individual members of the FABP family. This Snapshot describes the overall functions of FABPs in health and disease and highlights emerging roles of adipose FABP (A-FABP) and epidermal FABP (E-FABP) in the fields of obesity, chronic inflammation, and cancer development. To view this SnapShot, open or download the PDF.
Topics: Adipocytes; Fatty Acid-Binding Proteins; Humans; Macrophages; Models, Biological; Neoplasms; Obesity; Peroxisome Proliferator-Activated Receptors; Signal Transduction; Skin Diseases; Sterol Esterase
PubMed: 32822569
DOI: 10.1016/j.cell.2020.07.027 -
Trends in Molecular Medicine Jun 2023Lysosomal acid lipase (LAL) is the sole enzyme known to degrade neutral lipids in the lysosome. Mutations in the LAL-encoding LIPA gene lead to rare lysosomal lipid... (Review)
Review
Lysosomal acid lipase (LAL) is the sole enzyme known to degrade neutral lipids in the lysosome. Mutations in the LAL-encoding LIPA gene lead to rare lysosomal lipid storage disorders with complete or partial absence of LAL activity. This review discusses the consequences of defective LAL-mediated lipid hydrolysis on cellular lipid homeostasis, epidemiology, and clinical presentation. Early detection of LAL deficiency (LAL-D) is essential for disease management and survival. LAL-D must be considered in patients with dyslipidemia and elevated aminotransferase concentrations of unknown etiology. Enzyme replacement therapy, sometimes in combination with hematopoietic stem cell transplantation (HSCT), is currently the only therapy for LAL-D. New technologies based on mRNA and viral vector gene transfer are recent efforts to provide other effective therapeutic strategies.
Topics: Humans; Wolman Disease; Sterol Esterase; Hematopoietic Stem Cell Transplantation; Lipids
PubMed: 37028992
DOI: 10.1016/j.molmed.2023.03.001 -
Nature Metabolism Oct 2022Cysteine dioxygenase 1 (Cdo1) is a key enzyme in taurine synthesis. Here we show that Cdo1 promotes lipolysis in adipose tissue. Adipose-specific knockout of Cdo1 in...
Cysteine dioxygenase 1 (Cdo1) is a key enzyme in taurine synthesis. Here we show that Cdo1 promotes lipolysis in adipose tissue. Adipose-specific knockout of Cdo1 in mice impairs energy expenditure, cold tolerance and lipolysis, exacerbates diet-induced obesity (DIO) and decreases adipose expression of the key lipolytic genes encoding ATGL and HSL, with little effect on adipose taurine levels. White-adipose-specific overexpression of ATGL and HSL blunts the role of adipose Cdo1 deficiency in promoting DIO. Mechanistically, Cdo1 interacts with PPARγ and facilitates the recruitment of Med24, the core subunit of mediator complex, to ATGL and HSL gene promoters, thereby transactivating their expression. Further, mice with transgenic overexpression of Cdo1 show better cold tolerance, ameliorated DIO and higher lipolysis capacity. Thus, we uncover an unexpected and important role of Cdo1 in regulating adipose lipolysis.
Topics: Male; Mice; Animals; Lipolysis; PPAR gamma; Cysteine Dioxygenase; Sterol Esterase; Lipase; Adipose Tissue; Obesity; Mediator Complex; Taurine
PubMed: 36253617
DOI: 10.1038/s42255-022-00644-3 -
Autophagy Jul 2017Excess triglyceride (TG) accumulation in the liver underlies fatty liver disease, a highly prevalent ailment. TG occurs in the liver sequestered in lipid droplets, the...
Excess triglyceride (TG) accumulation in the liver underlies fatty liver disease, a highly prevalent ailment. TG occurs in the liver sequestered in lipid droplets, the major lipid storage organelle. Lipid droplets are home to the lipid droplet proteins, the most abundant of which are the perilipins (PLINs), encoded by 5 different genes, Plin1 to Plin5. Of the corresponding gene products, PLIN2 is the only constitutive and ubiquitously expressed lipid droplet protein that has been used as a protein marker for lipid droplets. We and others reported that plin2 mice have an ∼60% reduction in TG content, and are protected against fatty liver disease. Here we show that PLIN2 overexpression protects lipid droplets against macroautophagy/autophagy, whereas PLIN2 deficiency enhances autophagy and depletes hepatic TG. The enhanced autophagy in plin2 mice protects against severe ER stress-induced hepatosteatosis and hepatocyte apoptosis. In contrast, hepatic TG depletion resulting from other genetic and pharmacological manipulations has no effect on autophagy. Importantly, PLIN2 deficiency lowers cellular TG content in wild-type mouse embryonic fibroblasts (MEFs) via enhanced autophagy, but does not affect cellular TG content in atg7 MEFs that are devoid of autophagic function. Conversely, adenovirus-shAtg7-mediated hepatic Atg7 knockdown per se does not alter the hepatic TG level, suggesting a more complex regulation in vivo. In sum, PLIN2 guards its own house, the lipid droplet. PLIN2 overexpression protects against autophagy, and its downregulation stimulates TG catabolism via autophagy.
Topics: Animals; Autophagy; Autophagy-Related Protein 7; Carrier Proteins; Cells, Cultured; Endoplasmic Reticulum Stress; Hepatocytes; Liver; Mice; Mice, Knockout; Mitophagy; Perilipin-2; Sterol Esterase; Triglycerides
PubMed: 28548876
DOI: 10.1080/15548627.2017.1319544 -
Nature Metabolism Jan 2024Adipose tissue lipolysis is mediated by cAMP-protein kinase A (PKA)-dependent intracellular signalling. Here, we show that PKA targets p21-activated kinase 4 (PAK4),...
Adipose tissue lipolysis is mediated by cAMP-protein kinase A (PKA)-dependent intracellular signalling. Here, we show that PKA targets p21-activated kinase 4 (PAK4), leading to its protein degradation. Adipose tissue-specific overexpression of PAK4 in mice attenuates lipolysis and exacerbates diet-induced obesity. Conversely, adipose tissue-specific knockout of Pak4 or the administration of a PAK4 inhibitor in mice ameliorates diet-induced obesity and insulin resistance while enhancing lipolysis. Pak4 knockout also increases energy expenditure and adipose tissue browning activity. Mechanistically, PAK4 directly phosphorylates fatty acid-binding protein 4 (FABP4) at T126 and hormone-sensitive lipase (HSL) at S565, impairing their interaction and thereby inhibiting lipolysis. Levels of PAK4 and the phosphorylation of FABP4-T126 and HSL-S565 are enhanced in the visceral fat of individuals with obesity compared to their lean counterparts. In summary, we have uncovered an important role for FABP4 phosphorylation in regulating adipose tissue lipolysis, and PAK4 inhibition may offer a therapeutic strategy for the treatment of obesity.
Topics: Animals; Mice; Fatty Acid-Binding Proteins; Lipolysis; Obesity; p21-Activated Kinases; Sterol Esterase
PubMed: 38216738
DOI: 10.1038/s42255-023-00957-x -
Progress in Lipid Research Apr 2021Hormone-sensitive lipase (HSL) was initially characterized as the hormonally regulated neutral lipase activity responsible for the breakdown of triacylglycerols into... (Review)
Review
Hormone-sensitive lipase (HSL) was initially characterized as the hormonally regulated neutral lipase activity responsible for the breakdown of triacylglycerols into fatty acids in adipose tissue. This review aims at providing up-to-date information on structural properties, regulation of expression, activity and function as well as therapeutic potential. The lipase is expressed as different isoforms produced from tissue-specific alternative promoters. All isoforms are composed of an N-terminal domain and a C-terminal catalytic domain within which a regulatory domain containing the phosphorylation sites is embedded. Some isoforms possess additional N-terminal regions. The catalytic domain shares similarities with bacteria, fungus and vascular plant proteins but not with other mammalian lipases. HSL singularity is provided by regulatory and N-terminal domains sharing no homology with other proteins. HSL has a broad substrate specificity compared to other neutral lipases. It hydrolyzes acylglycerols, cholesteryl and retinyl esters among other substrates. A novel role of HSL, independent of its enzymatic function, has recently been described in adipocytes. Clinical studies revealed dysregulations of HSL expression and activity in disorders, such as lipodystrophy, obesity, type 2 diabetes and cancer-associated cachexia. Development of specific inhibitors positions HSL as a pharmacological target for the treatment of metabolic complications.
Topics: Adipocytes; Adipose Tissue; Animals; Diabetes Mellitus, Type 2; Lipolysis; Sterol Esterase
PubMed: 33387571
DOI: 10.1016/j.plipres.2020.101084 -
TheScientificWorldJournal 2022Hormone-sensitive lipase (HSL) is a pivotal enzyme that mediates triglyceride hydrolysis to provide free fatty acids and glycerol in adipocytes in a hormonally... (Review)
Review
Hormone-sensitive lipase (HSL) is a pivotal enzyme that mediates triglyceride hydrolysis to provide free fatty acids and glycerol in adipocytes in a hormonally controlled lipolysis process. Elevated plasma-free fatty acids were accompanied by insulin resistance, type-2 diabetes, and obesity. Inhibition of lipolysis through HSL inhibition may provide a mechanism to prevent the accumulation of free fatty acids and to improve the affectability of insulin and blood glucose handling in type II diabetes. The published studies that examine the structure, regulation, and function of HSL and major inhibitors were reviewed in this paper.
Topics: Humans; Sterol Esterase; Fatty Acids, Nonesterified; Diabetes Mellitus, Type 2; Lipase; Lipolysis
PubMed: 36530555
DOI: 10.1155/2022/1964684 -
Drug Design, Development and Therapy 2020Lysosomal acid lipase (LAL) deficiency is a metabolic (storage) disorder, encompassing a severe (Wolman disease) and attenuated (Cholesterol ester storage disease)... (Review)
Review
Lysosomal acid lipase (LAL) deficiency is a metabolic (storage) disorder, encompassing a severe (Wolman disease) and attenuated (Cholesterol ester storage disease) subtype; both inherited as autosomal recessive traits. Cardinal clinical features include the combination of hepatic dysfunction and dyslipidemia, as a consequence of cholesteryl esters and triglyceride accumulation, predominately in the liver and vascular and reticuloendothelial system. Significant morbidity can arise, due to liver failure and/or atherosclerosis; in part related to the severity of the underlying gene defect and corresponding enzyme deficiency. Diagnosis is based on demonstration of decreased LAL enzyme activity, complemented by analysis of the cognate gene defects. Therapeutic options include dietary manipulation and the use of lipid-lowering drugs. Sebelipase alfa, a recombinant enzyme replacement therapy, has garnered regulatory approval, following demonstration of improvements in disease-relevant markers and clinical benefit in clinical trials, which included increased survival in the most severe cases.
Topics: Animals; Atherosclerosis; Cholesterol Ester Storage Disease; Humans; Hypolipidemic Agents; Liver Failure; Severity of Illness Index; Sterol Esterase; Wolman Disease
PubMed: 32103901
DOI: 10.2147/DDDT.S149264 -
Applied Microbiology and Biotechnology Mar 2016According to their substrate preferences, carboxylic ester hydrolases are organized in smaller clusters. Among them, sterol esterases (EC 3.1.1.13), also known as... (Review)
Review
According to their substrate preferences, carboxylic ester hydrolases are organized in smaller clusters. Among them, sterol esterases (EC 3.1.1.13), also known as cholesterol esterases, act on fatty acid esters of cholesterol and other sterols in aqueous media, and are also able to catalyze synthesis by esterification or transesterification in the presence of organic solvents. Mammalian cholesterol esterases are intracellular enzymes that have been extensively studied since they are essential in lipid metabolism and cholesterol absorption, and the natural role of some microbial sterol esterases is supposed to be similar. However, besides these intracellular enzymes, a number of microbes produce extracellular sterol esterases, which show broad stability, selectivity, or wide substrate specificity, making them interesting for the industry. In spite of this, there is little information about microbial sterol esterases, and only a small amount of them have been characterized. Some of the most commercially exploited cholesterol esterases are produced by Pseudomonas species and by Candida rugosa, although in the last case they are usually described and named as "high substrate versatility lipases." From a structural point of view, most of them belong to the α/β-hydrolase superfamily and have a conserved "catalytic triad" formed by His, an acidic amino acid and a Ser residue that is located in a highly conserved GXSXG sequence. In this review, the information available on microbial sterol esterases has been gathered, taking into account their origin, production and purification, heterologous expression, structure, stability, or substrate specificity, which are the main properties that make them attractive for different applications. Moreover, a comprehensive phylogenetic analysis on available sequences of cholesterol esterases has been done, including putative sequences deduced from public genomes.
Topics: Bacteria; Fungi; Phylogeny; Protein Conformation; Sterol Esterase; Substrate Specificity
PubMed: 26743653
DOI: 10.1007/s00253-015-7258-x