Various strategies have been employed to improve the reliability of 2D, 3D, and co-culture in vitro models of nonalcoholic fatty liver disease, including using extracellular matrix proteins such as collagen I to promote cell adhesion. While studies have demonstrated the significant benefits of culturing cells on collagen I, its effects on the HepG2 cell line after exposure to palmitate (PA) have not been investigated. Therefore, this study aimed to assess the effects of PA-induced lipotoxicity in HepG2 cultured in the absence or presence of collagen I. HepG2 cultured in the absence or presence of collagen I was exposed to PA, followed by analyses that assessed cell proliferation, viability, adhesion, cell death, mitochondrial respiration, reactive oxygen species production, gene and protein expression, and triacylglycerol accumulation. Culturing HepG2 on collagen I was associated with increased cell proliferation, adhesion, and expression of integrin receptors, and improved cellular spreading compared to culturing them in the absence of collagen I. However, PA-induced lipotoxicity was greater in collagen I-cultured HepG2 than in those cultured in the absence of collagen I and was associated with increased α2β1 receptors. In summary, the present study demonstrated for the first time that collagen I-cultured HepG2 exhibited exacerbated cell death following exposure to PA through integrin-mediated death. The findings from this study may serve as a caution to those using 2D models or 3D scaffold-based models of HepG2 in the presence of collagen I.

• MeSH
• Cell Adhesion * drug effects   MeSH
• Cell Death drug effects   MeSH
• Hep G2 Cells MeSH
• Integrin alpha2beta1 metabolism   MeSH
• Integrins metabolism   genetics   MeSH
• Collagen Type I * metabolism   genetics   MeSH
• Humans MeSH
• Non-alcoholic Fatty Liver Disease metabolism   pathology   MeSH
• Palmitates toxicity   pharmacology   MeSH
• Cell Proliferation * drug effects   MeSH
• Reactive Oxygen Species metabolism   MeSH
• Cell Survival * drug effects   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH

Disruption of adipocyte de novo lipogenesis (DNL) by deletion of fatty acid synthase (FASN) in mice induces browning in inguinal white adipose tissue (iWAT). However, adipocyte FASN knockout (KO) increases acetyl-coenzyme A (CoA) and malonyl-CoA in addition to depletion of palmitate. We explore which of these metabolite changes triggers adipose browning by generating eight adipose-selective KO mouse models with loss of ATP-citrate lyase (ACLY), acetyl-CoA carboxylase 1 (ACC1), ACC2, malonyl-CoA decarboxylase (MCD) or FASN, or dual KOs ACLY/FASN, ACC1/FASN, and ACC2/FASN. Preventing elevation of acetyl-CoA and malonyl-CoA by depletion of adipocyte ACLY or ACC1 in combination with FASN KO does not block the browning of iWAT. Conversely, elevating malonyl-CoA levels in MCD KO mice does not induce browning. Strikingly, adipose ACC1 KO induces a strong iWAT thermogenic response similar to FASN KO while also blocking malonyl-CoA and palmitate synthesis. Thus, ACC1 and FASN are strong suppressors of adipocyte thermogenesis through promoting lipid synthesis rather than modulating the DNL intermediates acetyl-CoA or malonyl-CoA.

• MeSH
• Acetyl-CoA Carboxylase * metabolism   MeSH
• Acetyl Coenzyme A metabolism   MeSH
• Mice, Knockout MeSH
• Mice MeSH
• Palmitates metabolism   MeSH
• Fatty Acid Synthases metabolism   MeSH
• Thermogenesis MeSH
• Adipocytes * metabolism   MeSH
• Animals MeSH
• Check Tag
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, N.I.H., Extramural MeSH

Thermogenesis in brown adipose tissue (BAT) uses intracellular triglycerides, circulating free fatty acids and glucose as the main substrates. The objective of the current study was to analyse the role of CD36 fatty acid translocase in regulation of glucose and fatty acid utilisation in BAT. BAT isolated from spontaneously hypertensive rat (SHR) with mutant Cd36 gene and SHR-Cd36 transgenic rats with wild type variant was incubated in media containing labeled glucose and palmitate to measure substrate incorporation and oxidation. SHR-Cd36 versus SHR rats showed significantly increased glucose incorporation into intracellular lipids associated with reduced glycogen synthase kinase 3β (GSK-3β) protein expression and phosphorylation and increased oxidation of exogenous palmitate. It can be concluded that CD36 enhances glucose transport for lipogenesis in BAT by suppressing GSK-3β and promotes direct palmitate oxidation.

• MeSH
• CD36 Antigens genetics   metabolism   MeSH
• Glucose * metabolism   MeSH
• Adipose Tissue, Brown * metabolism   MeSH
• Glycogen Synthase Kinase 3 beta metabolism   MeSH
• Rats MeSH
• Fatty Acids metabolism   MeSH
• Palmitates metabolism   MeSH
• Rats, Inbred SHR MeSH
• Rats, Transgenic MeSH
• Animals MeSH
• Check Tag
• Rats MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

Metabolic rewiring is often considered an adaptive pressure limiting metastasis formation; however, some nutrients available at distant organs may inherently promote metastatic growth. We find that the lung and liver are lipid-rich environments. Moreover, we observe that pre-metastatic niche formation increases palmitate availability only in the lung, whereas a high-fat diet increases it in both organs. In line with this, targeting palmitate processing inhibits breast cancer-derived lung metastasis formation. Mechanistically, breast cancer cells use palmitate to synthesize acetyl-CoA in a carnitine palmitoyltransferase 1a-dependent manner. Concomitantly, lysine acetyltransferase 2a expression is promoted by palmitate, linking the available acetyl-CoA to the acetylation of the nuclear factor-kappaB subunit p65. Deletion of lysine acetyltransferase 2a or carnitine palmitoyltransferase 1a reduces metastasis formation in lean and high-fat diet mice, and lung and liver metastases from patients with breast cancer show coexpression of both proteins. In conclusion, palmitate-rich environments foster metastases growth by increasing p65 acetylation, resulting in a pro-metastatic nuclear factor-kappaB signaling.

• MeSH
• Acetylation MeSH
• Acetyl Coenzyme A metabolism   MeSH
• Carnitine O-Palmitoyltransferase metabolism   MeSH
• Lysine Acetyltransferases * metabolism   MeSH
• Mice MeSH
• NF-kappa B * metabolism   MeSH
• Palmitates MeSH
• Animals MeSH
• Check Tag
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

Natural compounds may bear promising therapeutic benefits against metabolic diseases such as type 2 diabetes mellitus (T2DM), which are characterized by a state of insulin resistance and mitochondrial dysfunction. Here, we examined the cellular mechanisms by which aspalathin, a dihydrochalcone C-glucoside unique to rooibos, may ameliorate palmitate-induced insulin resistance and mitochondrial dysfunction in cultured C2C12 myotubules. This current study demonstrated that aspalathin remains effective in improving glucose uptake in insulin-resistant skeletal muscle cells, supported by the upregulation of insulin-dependent signaling that involves the activation of insulin receptor (IR) and direct phosphorylation of protein kinase B (AKT). Interestingly, aspalathin also improved mitochondrial respiration and function, which was evident by an increased expression of carnitine palmitoyltransferase 1 (Cpt1), fatty acid transport protein 1 (Fatp1), sirtuin 1 (Sirt1), nuclear respiratory factor 1 (Nrf1), and transcription factor A, mitochondrial (Tfam). Importantly, our results showed that aspalathin treatment was effective in ameliorating the devastating outcomes of insulin resistance and mitochondrial dysfunction that are linked with an undesired pro-inflammatory response, by reducing the levels of well-known pro-inflammatory markers such as interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha), and protein kinase C-theta (PKC-theta). Thus, beyond improving glucose uptake and insulin signaling, the current study brings a new perspective in the therapeutic benefits of aspalathin in improving mitochondrial respiration and blocking inflammation to attenuate the detrimental effect of palmitate in skeletal muscle cells.

• MeSH
• Diabetes Mellitus, Type 2 * metabolism   MeSH
• Glucose metabolism   MeSH
• Insulin pharmacology   MeSH
• Insulin Resistance * physiology   MeSH
• Muscle Fibers, Skeletal metabolism   MeSH
• Muscle, Skeletal metabolism   MeSH
• Humans MeSH
• Mitochondria metabolism   MeSH
• Palmitates MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH

Hepatic steatosis associated with high-fat diet, obesity, and type 2 diabetes is thought to be the major driver of severe liver inflammation, fibrosis, and cirrhosis. Cytosolic acetyl CoA (AcCoA), a central metabolite and substrate for de novo lipogenesis (DNL), is produced from citrate by ATP-citrate lyase (ACLY) and from acetate through AcCoA synthase short chain family member 2 (ACSS2). However, the relative contributions of these two enzymes to hepatic AcCoA pools and DNL rates in response to high-fat feeding are unknown. We report here that hepatocyte-selective depletion of either ACSS2 or ACLY caused similar 50% decreases in liver AcCoA levels in obese mice, showing that both pathways contribute to the generation of this DNL substrate. Unexpectedly however, the hepatocyte ACLY depletion in obese mice paradoxically increased total DNL flux measured by D2O incorporation into palmitate, whereas in contrast, ACSS2 depletion had no effect. The increase in liver DNL upon ACLY depletion was associated with increased expression of nuclear sterol regulatory element-binding protein 1c and of its target DNL enzymes. This upregulated DNL enzyme expression explains the increased rate of palmitate synthesis in ACLY-depleted livers. Furthermore, this increased flux through DNL may also contribute to the observed depletion of AcCoA levels because of its increased conversion to malonyl CoA and palmitate. Together, these data indicate that in fat diet-fed obese mice, hepatic DNL is not limited by its immediate substrates AcCoA or malonyl CoA but rather by activities of DNL enzymes.

• MeSH
• Acetyl Coenzyme A metabolism   MeSH
• Adenosine Triphosphate metabolism   MeSH
• ATP Citrate (pro-S)-Lyase genetics   metabolism   MeSH
• Diabetes Mellitus, Type 2 * metabolism   MeSH
• Hepatocytes metabolism   MeSH
• Liver * metabolism   MeSH
• Lipogenesis * MeSH
• Malonyl Coenzyme A metabolism   MeSH
• Mice, Obese MeSH
• Mice MeSH
• Palmitates metabolism   MeSH
• Sterol Regulatory Element Binding Protein 1 * genetics   metabolism   MeSH
• Animals MeSH
• Check Tag
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Research Support, N.I.H., Extramural MeSH

Triacylglycerols (TAGs) containing positional isomers of hypogeic (Hy), palmitoleic (Po), and palmitvaccenic (Pv) acids from three microorganisms (top-fermenting brewer's yeast Saccharomyces cerevisiae, green alga Coccomyxa elongata, and arbuscular mycorrhizal (AM) fungus Rhizophagus irregularis) were analyzed. Dozens of regioisomers and enantiomers of TAGs containing one, two or three hexadecenoic acids have been identified by means of reversed phase chromatography/mass spectrometry (RP-HPLC/MS). The regioisomers of TAGs containing two palmitic acids and any hexadecenoic acid were separated. Analysis of regioisomers of TAGs having one Pv residue showed that asymmetric molecular species such as PvPP or PPPv were dominant in Rhizophagus. TAGs were also analyzed on a chiral phase column and nine molecular species of TAGs containing two palmitic and any of three hexadecenoic acids were separated and identified. In the case of TAGs containing one palmitic and two hexadecenoic acids, the separation was successful only if the hexadecenoic acids were identical. Separation of TAGs containing three hexadecenoic acids was successful only if all three hexadecenoic acids were identical. Regardless of the type of TAG, it was found that TAGs in the AM fungus and containing palmitvaccenic acid bound at the sn-1 position of the glycerol backbone were dominant, suggesting similarity in the biosynthesis of the different TAGs. The covalent adduct chemical ionization method was used for identification of TAGs as adduct with (1-methyleneimino)-1-ethenyl ion, which reacted with double bond of the unsaturated fatty acid. Tandem MS thus makes it possible to identify TAGs containing various hexadecenoic acids.

• MeSH
• Chromatography, Liquid MeSH
• Mass Spectrometry methods   MeSH
• Palmitic Acids * MeSH
• Fatty Acids * analysis   MeSH
• Triglycerides analysis   MeSH
• Chromatography, High Pressure Liquid methods   MeSH
• Publication type
• Journal Article MeSH

Breast milk is a complex mixture containing underexplored bioactive lipids. We performed an observational case-control study to compare the impact of delivery mode: caesarean section (CS) and vaginal birth (VB); and term (preterm and term delivery) on the levels of lipokines in human milk at different stages of lactation. Metabolomic analysis of the milk identified triacylglycerol estolides as a metabolic reservoir of the anti-inflammatory lipid mediator 5-palmitic acid ester of hydroxystearic acid (5-PAHSA). We found that triacylglycerol estolides were substrates of carboxyl ester lipase and 5-PAHSA-containing lipids were the least preferred substrates among tested triacylglycerol estolide isomers. This explained exceptionally high colostrum levels of 5-PAHSA in the VB group. CS and preterm birth negatively affected colostrum lipidome, including 5-PAHSA levels, but the lipidomic profiles normalized in mature milk. Mothers delivering term babies vaginally produce colostrum rich in 5-PAHSA, which could contribute to the prevention of intestinal inflammation in newborns.

• MeSH
• Cesarean Section MeSH
• Esters metabolism   MeSH
• Infant MeSH
• Colostrum metabolism   MeSH
• Palmitic Acid metabolism   MeSH
• Lactation MeSH
• Humans MeSH
• Lipase metabolism   MeSH
• Milk, Human * metabolism   MeSH
• Infant, Newborn MeSH
• Premature Birth * metabolism   MeSH
• Case-Control Studies MeSH
• Pregnancy MeSH
• Triglycerides metabolism   MeSH
• Check Tag
• Infant MeSH
• Humans MeSH
• Infant, Newborn MeSH
• Pregnancy MeSH
• Female MeSH
• Publication type
• Journal Article MeSH

Lipidy v mateřském mléce (MM) jsou převážně zdrojem energie vedle esenciálních vitaminů, mastných kyselin (MK), komplexních lipidů a bioaktivních látek. 98-99 % lipidů v MM jsou ve formě triacylglycerolů (TG) obsaženy v tukových kuličkách, jejichž vlastnosti závisí na složení inkorporovaných MK. Membrána pokrývající tukové kuličky (MFGM) v mateřském mléce (MM) obsahuje mnoho bioaktivních komponent. Biologickou důležitost a prospěšnost suplementace kojeneckých formulí o MFGM komponenty pro zdravý vývoj kojenců prokázaly klinické kontrolované studie. MFGM koncentráty ovlivňují neurokognitivní vývoj, chování, imunitu a protektivní mechanismy proti infekci. Zvýšený obsah mléčného tuku v kojenecké výživě zajistí fyziologicky požadovaný obsah kyseliny palmitové při odstranění palmového oleje z kojeneckých formulí. Kyselina dokosahexaenová (DHA) a arachidonová (ARA) zlepšuje kognitivní funkce a redukuje výskyt astmatu ve školním věku obzvláště u dětí s geneticky sníženou syntézou těchto LC-PUFA. Odborné studie podporují obohacení kojeneckých formulí o omega-3 DHA společně s omega-6 ARA, avšak současná EU legislativa doporučuje vysoký obsah DHA bez požadavku na ARA. Technologický pokrok umožnuje obohacení o nové lipidové preparáty a otevírá nové možnosti studia biologických účinků komponent MFGM při suplementaci kojeneckých formulí. Cílem těchto moderních nutričních intervencí je dosáhnout snížení rozdílu mezi kojenými a nekojenými dětmi.

Lipids in human milk represent a major source of energy, but they also provide essential nutrients such as fat soluble vitamins, fatty acids and bioactive components. Milk lipids are primarily found as triacylglycerols (TG) inside fat globules accounting for over 98% of the fat content, and its composition in fatty acids defines its nutritional and physiological properties. The clinical trials exploring the effects of components from bovine milk fat globule membrane (MFGM) concentrates and complex lipid preparations supplemented to infants have shown promising indications for safety and positive effects on infant neurodevelopment and cognitive functions, reduction of infection risk and positive health benefits. The supply of omega-3 docosahexaenoic acid (DHA) and omega-6 arachidonic acid (ARA) is related to appropriate infant brain and tissue development, neurocognitive development and to reducing asthma bronchiale at school age, whereas the current recommendation now includes addition of preformed DHA, but not ARA. The provision of preparations of complex milk lipids rich in palmitic acid with infant formula provides adequate alternatives that are needed for infant development without adding palm oil. These specific aspects of MFGM achieving good health of children and how they may relate to infant development, physiological function, infant formula feeding and advances in diary technology will be addressed in more detail below.

• Keywords
• membrámy tukových kuliček,
• MeSH
• Infant MeSH
• Breast Feeding * MeSH
• Arachidonic Acid MeSH
• Palmitic Acid MeSH
• Docosahexaenoic Acids MeSH
• Humans MeSH
• Milk, Human * chemistry   MeSH
• Infant Formula chemistry   MeSH
• Check Tag
• Infant MeSH
• Humans MeSH
• Publication type
• Research Support, Non-U.S. Gov't MeSH
• Review MeSH

Monocyte homing to the liver and adhesion to the liver sinusoidal endothelial cells (LSECs) are key elements in nonalcoholic steatohepatitis (NASH) pathogenesis. We reported previously that VCAM-1 mediates monocyte adhesion to LSECs. However, the pathogenic role of VCAM-1 in NASH is unclear. Herein, we report that VCAM-1 was a top upregulated adhesion molecule in the NASH mouse liver transcriptome. Open chromatin landscape profiling combined with genome-wide transcriptome analysis showed robust transcriptional upregulation of LSEC VCAM-1 in murine NASH. Moreover, LSEC VCAM-1 expression was significantly increased in human NASH. LSEC VCAM-1 expression was upregulated by palmitate treatment in vitro and reduced with inhibition of the mitogen-activated protein 3 kinase (MAP3K) mixed lineage kinase 3 (MLK3). Likewise, LSEC VCAM-1 expression was reduced in the Mlk3-/- mice with diet-induced NASH. Furthermore, VCAM-1 neutralizing Ab or pharmacological inhibition attenuated diet-induced NASH in mice, mainly via reducing the proinflammatory monocyte hepatic population as examined by mass cytometry by time of flight (CyTOF). Moreover, endothelium-specific Vcam1 knockout mice were also protected against NASH. In summary, lipotoxic stress enhances the expression of LSEC VCAM-1, in part, through MLK3 signaling. Inhibition of VCAM-1 was salutary in murine NASH and might serve as a potential therapeutic strategy for human NASH.

• MeSH
• Vascular Cell Adhesion Molecule-1 antagonists & inhibitors   genetics   metabolism   MeSH
• Endothelial Cells drug effects   metabolism   MeSH
• Liver drug effects   metabolism   pathology   MeSH
• Humans MeSH
• MAP Kinase Signaling System drug effects   MeSH
• RNA, Messenger genetics   MeSH
• Disease Models, Animal MeSH
• Mice, Inbred C57BL MeSH
• Mice, Knockout MeSH
• Mice MeSH
• Non-alcoholic Fatty Liver Disease etiology   genetics   metabolism   MeSH
• Antibodies, Neutralizing administration & dosage   MeSH
• Palmitates toxicity   MeSH
• Gene Expression Profiling MeSH
• Up-Regulation drug effects   MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Research Support, N.I.H., Extramural MeSH