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Genomics, Proteomics & Bioinformatics Oct 2021Oleic acid (OA), a monounsaturated fatty acid (MUFA), has previously been shown to reverse saturated fatty acid palmitic acid (PA)-induced hepatic insulin resistance...
Oleic acid (OA), a monounsaturated fatty acid (MUFA), has previously been shown to reverse saturated fatty acid palmitic acid (PA)-induced hepatic insulin resistance (IR). However, its underlying molecular mechanism is unclear. In addition, previous studies have shown that eicosapentaenoic acid (EPA), a ω-3 polyunsaturated fatty acid (PUFA), reverses PA-induced muscle IR, but whether EPA plays the same role in hepatic IR and its possible mechanism involved need to be further clarified. Here, we confirmed that EPA reversed PA-induced IR in HepG2 cells and compared the proteomic changes in HepG2 cells after treatment with different free fatty acids (FFAs). A total of 234 proteins were determined to be differentially expressed after PA+OA treatment. Their functions were mainly related to responses to stress and endogenous stimuli, lipid metabolic process, and protein binding. For PA+EPA treatment, the PA-induced expression changes of 1326 proteins could be reversed by EPA, 415 of which were mitochondrial proteins, with most of the functional proteins involved in oxidative phosphorylation (OXPHOS) and tricarboxylic acid (TCA) cycle. Mechanistic studies revealed that the protein encoded by JUN and reactive oxygen species (ROS) play a role in OA- and EPA-reversed PA-induced IR, respectively. EPA and OA alleviated PA-induced abnormal adenosine triphosphate (ATP) production, ROS generation, and calcium (Ca) content. Importantly, HO-activated production of ROS increased the protein expression of JUN, further resulting in IR in HepG2 cells. Taken together, we demonstrate that ROS/JUN is a common response pathway employed by HepG2 cells toward FFA-regulated IR.
Topics: Eicosapentaenoic Acid; Hep G2 Cells; Humans; Hydrogen Peroxide; Insulin Resistance; Oleic Acid; Palmitic Acid; Proteomics; Reactive Oxygen Species
PubMed: 33631425
DOI: 10.1016/j.gpb.2019.06.005 -
Proceedings of the National Academy of... Mar 2003Excess lipid accumulation in non-adipose tissues is associated with insulin resistance, pancreatic beta-cell apoptosis and heart failure. Here, we demonstrate in...
Excess lipid accumulation in non-adipose tissues is associated with insulin resistance, pancreatic beta-cell apoptosis and heart failure. Here, we demonstrate in cultured cells that the relative toxicity of two common dietary long chain fatty acids is related to channeling of these lipids to distinct cellular metabolic fates. Oleic acid supplementation leads to triglyceride accumulation and is well tolerated, whereas excess palmitic acid is poorly incorporated into triglyceride and causes apoptosis. Unsaturated fatty acids rescue palmitate-induced apoptosis by channeling palmitate into triglyceride pools and away from pathways leading to apoptosis. Moreover, in the setting of impaired triglyceride synthesis, oleate induces lipotoxicity. Our findings support a model of cellular lipid metabolism in which unsaturated fatty acids serve a protective function against lipotoxicity though promotion of triglyceride accumulation.
Topics: Animals; Apoptosis; CHO Cells; Cell Line; Cricetinae; Drug Resistance; Fatty Acid Desaturases; Fatty Acids; Lipid Metabolism; Mice; Models, Biological; Oleic Acid; Palmitic Acid; Triglycerides
PubMed: 12629214
DOI: 10.1073/pnas.0630588100 -
Biomolecules Aug 2020α-Lactalbumin (α-LA) is a small (Mr 14,200), acidic (pI 4-5), Ca-binding protein. α-LA is a regulatory component of lactose synthase enzyme system functioning in the... (Review)
Review
α-Lactalbumin (α-LA) is a small (Mr 14,200), acidic (pI 4-5), Ca-binding protein. α-LA is a regulatory component of lactose synthase enzyme system functioning in the lactating mammary gland. The protein possesses a single strong Ca-binding site, which can also bind Mg, Mn, Na, K, and some other metal cations. It contains several distinct Zn-binding sites. Physical properties of α-LA strongly depend on the occupation of its metal binding sites by metal ions. In the absence of bound metal ions, α-LA is in the molten globule-like state. The binding of metal ions, and especially of Ca, increases stability of α-LA against the action of heat, various denaturing agents and proteases, while the binding of Zn to the Ca-loaded protein decreases its stability and causes its aggregation. At pH 2, the protein is in the classical molten globule state. α-LA can associate with membranes at neutral or slightly acidic pH at physiological temperatures. Depending on external conditions, α-LA can form amyloid fibrils, amorphous aggregates, nanoparticles, and nanotubes. Some of these aggregated states of α-LA can be used in practical applications such as drug delivery to tissues and organs. α-LA and some of its fragments possess bactericidal and antiviral activities. Complexes of partially unfolded α-LA with oleic acid are cytotoxic to various tumor and bacterial cells. α-LA in the cytotoxic complexes plays a role of a delivery carrier of cytotoxic fatty acid molecules into tumor and bacterial cells across the cell membrane. Perhaps in the future the complexes of α-LA with oleic acid will be used for development of new anti-cancer drugs.
Topics: Animals; Antineoplastic Agents; Humans; Hydrogen-Ion Concentration; Lactalbumin; Neoplasms; Oleic Acid
PubMed: 32825311
DOI: 10.3390/biom10091210 -
Molecules (Basel, Switzerland) Aug 2022Pancreatic lipase catalyzes the cleavage of triacylglycerols at the oil-water interface, and is known as the dominant determiner of dietary fat digestion. Reducing...
Pancreatic lipase catalyzes the cleavage of triacylglycerols at the oil-water interface, and is known as the dominant determiner of dietary fat digestion. Reducing dietary fat digestion and absorption by modulating the activity of pancreatic lipase has become a favorable strategy to tackle obesity. Orlistat is, at present, the only pancreatic lipase inhibitor approved for the treatment of obesity; however, an array of gastrointestinal adverse effects associated with orlistat limits its tolerability. As a safe alternative to orlistat, a number of natural product-derived compounds with varying degrees of pancreatic lipase inhibitory activity have been reported. We herein reported that bioactivity-guided fractionation of sesame meal led to the identification of free linoleic acid and oleic acid as potent inhibitors of porcine pancreatic lipase in vitro with an IC50 of 23.1 µg/mL (82.4 µM) and 11.7 µg/mL (41.4 µM), respectively. In rats, a single oral dose of the mixture of these fatty acids significantly suppressed the elevation of blood triacylglycerol level following fat intake. These results substantiate the role of free linoleic acid and oleic acid as a novel class of natural product-derived functional molecules that act as pancreatic lipase inhibitors, and their potential for healthy, routine-based weight management.
Topics: Animals; Biological Products; Dietary Fats; Digestion; Linoleic Acid; Lipase; Obesity; Oleic Acid; Orlistat; Rats; Sesamum; Swine; Triglycerides
PubMed: 35956860
DOI: 10.3390/molecules27154910 -
American Journal of Physiology. Cell... May 2022Treatment of mouse preimplantation embryos with elevated palmitic acid (PA) reduces blastocyst development, whereas cotreatment with PA and oleic acid (OA) together...
Treatment of mouse preimplantation embryos with elevated palmitic acid (PA) reduces blastocyst development, whereas cotreatment with PA and oleic acid (OA) together rescues blastocyst development to control frequencies. To understand the mechanistic effects of PA and OA treatment on early mouse embryos, we investigated the effects of PA and OA, alone and in combination, on autophagy during preimplantation development in vitro. We hypothesized that PA would alter autophagic processes and that OA cotreatment would restore control levels of autophagy. Two-cell stage mouse embryos were placed into culture medium supplemented with 100 μM PA, 250 μM OA, 100 μM PA and 250 μM OA, or potassium simplex optimization media with amino acid (KSOMaa) medium alone (control) for 18-48 h. The results demonstrated that OA cotreatment slowed developmental progression after 30 h of cotreatment but restored control blastocyst frequencies by 48 h. PA treatment elevated light chain 3 (LC3)-II puncta and p62 levels per cell whereas OA cotreatment returned to control levels of autophagy by 48 h. Autophagic mechanisms are altered by nonesterified fatty acid (NEFA) treatments during mouse preimplantation development in vitro, where PA elevates autophagosome formation and reduces autophagosome degradation levels, whereas cotreatment with OA reversed these PA effects. Autophagosome-lysosome colocalization only differed between PA and OA alone treatment groups. These findings advance our understanding of the effects of free fatty acid exposure on preimplantation development, and they uncover principles that may underlie the associations between elevated fatty acid levels and overall declines in reproductive fertility.
Topics: Animals; Autophagy; Blastocyst; Culture Media; Fatty Acids, Nonesterified; Mice; Oleic Acid; Palmitic Acid
PubMed: 35319901
DOI: 10.1152/ajpcell.00414.2021 -
Nutrients Apr 2023A great number of chemically diverse pancreatic lipase (PL) inhibitors have been identified to tackle obesity; however, very few of them have entered clinical studies.... (Randomized Controlled Trial)
Randomized Controlled Trial
Effects of Free Linoleic Acid and Oleic Acid in Sesame Meal Extract as Pancreatic Lipase Inhibitors on Postprandial Triglyceridemia: A Randomized, Double-Blind, Placebo-Controlled, Crossover Study in Healthy Volunteers.
A great number of chemically diverse pancreatic lipase (PL) inhibitors have been identified to tackle obesity; however, very few of them have entered clinical studies. The ethanolic extract of sesame meal is a potent PL inhibitor, and its activity hinges exclusively on two free fatty acids: linoleic acid and oleic acid, which were proven to reduce postprandial triglyceride excursion in rats. Herein, to investigate the clinical efficacy of the sesame meal extract, in a crossover trial, 30 healthy volunteers were randomized to receive the sesame meal extract containing experimental food or placebo along with a high-fat meal. Treatment with the sesame meal extract significantly lowered the incremental postprandial serum triglyceride concentration and reduced the incremental area under the curve (iAUC) by 16.8% (-value = 0.03) compared to placebo. Significant decreases in postprandial remnant-like lipoprotein particle cholesterol and low-density lipoprotein particles were also observed, whereas high-density lipoprotein cholesterol was increased. These results suggest that treatment with the sesame meal extract significantly reduced the postprandial excursion of triglycerides and improved the lipidemic profile after high dietary fat intake in healthy individuals, indicating the substantial potential of free linoleic acid and oleic acid and natural products rich in these compounds for the management of obesity and related conditions.
Topics: Animals; Rats; Humans; Cross-Over Studies; Oleic Acid; Sesamum; Linoleic Acid; Lipase; Healthy Volunteers; Triglycerides; Cholesterol; Obesity; Postprandial Period; Dietary Fats
PubMed: 37049588
DOI: 10.3390/nu15071748 -
Advances in Nutrition (Bethesda, Md.) May 2015
Topics: Cardiovascular Diseases; Dietary Fats; Fatty Acids, Monounsaturated; Humans; Oleic Acid
PubMed: 25979493
DOI: 10.3945/an.114.005926 -
Current Opinion in Chemical Biology Oct 2022Raman microscopy has been used to deduce information about the distributions of endogenous biomolecules without exogenous labeling. Several functional groups, such as... (Review)
Review
Raman microscopy has been used to deduce information about the distributions of endogenous biomolecules without exogenous labeling. Several functional groups, such as alkynes (CC), nitriles (CN), and carbon-deuterium (C-D) bonds, have been employed in recent years as Raman tags to detect target molecules in cells. In this article, we review some recent advances in applications using deuterated fatty acids for lipid analysis, such as investigation of tumor-selective cytotoxicity of γ-linolenic acid (GLA), simultaneous two-color imaging of stearate and oleate using deuterated and protonated alkynes, Raman hyperspectral imaging, and analyses of the physical properties of lipids through spectral unmixing of the C-D vibrational frequencies. In addition, we review some advanced methods for observing intracellular metabolic activities, such as de novo lipogenesis from deuterium-labeled precursors.
Topics: Alkynes; Carbon; Deuterium; Fatty Acids; Nitriles; Oleic Acid; Spectrum Analysis, Raman; Stearates; gamma-Linolenic Acid
PubMed: 35792373
DOI: 10.1016/j.cbpa.2022.102181 -
Cell Communication and Signaling : CCS Oct 2023Abnormal platelet activation is a key factor in the occurrence and development of thrombotic diseases. However, the physiological mechanisms that underlie platelet...
BACKGROUND
Abnormal platelet activation is a key factor in the occurrence and development of thrombotic diseases. However, the physiological mechanisms that underlie platelet homeostasis remain unclear. Oleic acid, one of the most abundant lipids in the human diet, has potential antithrombotic effects. This study aimed to investigate the effects of oleic acid on platelet activation and thrombosis.
METHODS
Platelet aggregation, ATP release, and fibrinogen spread were evaluated to determine the role of oleic acid in platelet activation. A ferric chloride-induced carotid injury model was used to establish the effect of oleic acid on thrombus formation in vivo. Western blotting analysis and transfection experiments were performed to determine the mechanisms involved in this process.
RESULTS
Oleic acid inhibited platelet aggregation, granule release, and calcium mobilization. Furthermore, it inhibited the spread of platelets on fibrinogen. We also found that oleic acid delayed arterial thrombosis in mice, as demonstrated in a murine model of ferric chloride-induced carotid artery thrombosis. The molecular mechanism of its inhibition of platelet activity may be through the Syk-PLCγ2 and CaMKKβ/AMPKα/VASP pathways. In addition, we demonstrated that the phosphorylation of AMPK at Ser496 was an important mechanism of platelet activation.
CONCLUSIONS
Our study showed that oleic acid inhibits platelet activation and reduces thrombogenesis by inhibiting the phosphorylation of multiple signaling molecules, offering new insights into the research and development of antiplatelet drugs. Video Abstract.
Topics: Humans; Mice; Animals; Oleic Acid; Platelet Activation; Blood Platelets; Thrombosis; Phosphorylation; Collagen; Fibrinogen
PubMed: 37817162
DOI: 10.1186/s12964-023-01276-0 -
Microbial Cell Factories Apr 2022Fatty acid hydratases are unique to microorganisms. Their native function is the oxidation of unsaturated C-C bonds to enable detoxification of environmental toxins.... (Review)
Review
Fatty acid hydratases are unique to microorganisms. Their native function is the oxidation of unsaturated C-C bonds to enable detoxification of environmental toxins. Within this enzyme family, the oleate hydratases (Ohys), which catalyze the hydroxylation of oleic acid to 10-(R)-hydroxy stearic acid (10-HSA) have recently gained particular industrial interest. 10-HSA is considered to be a replacement for 12-(R)-hydroxy stearic acid (12-HSA), which has a broad application in the chemical and pharmaceutical industry. As 12-HSA is obtained through an energy consuming synthesis process, the biotechnological route for sustainable 10-HSA production is of significant industrial interest. All Ohys identified to date have a non-redox active FAD bound in their active site. Ohys can be divided in several subfamilies, that differ in their oligomerization state and the decoration with amino acids in their active sites. The latter observation indicates a different reaction mechanism across those subfamilies. Despite intensive biotechnological, biochemical and structural investigations, surprising little is known about substrate binding and the reaction mechanism of this enzyme family. This review, summarizes our current understanding of Ohys with a focus on sustainable biotransformation.
Topics: Biodegradation, Environmental; Catalysis; Catalytic Domain; Hydro-Lyases; Oleic Acid; Oxidation-Reduction; Stearic Acids
PubMed: 35397585
DOI: 10.1186/s12934-022-01777-6