Role of the AMP-activated protein kinase in regulating fatty acid metabolism during exerciseThis paper is one of a selection of papers published in this Special Issue, entitled 14th International Biochemistry of Exercise Conference – Muscles as Molecular and Metabolic Machines, and has undergone the Journal’s usual peer review process.

2009 ◽  
Vol 34 (3) ◽  
pp. 315-322 ◽  
Author(s):  
Gregory R. Steinberg
Keyword(s):  
Skeletal Muscle ◽  
Fatty Acids ◽  
Adipose Tissue ◽  
Fatty Acid ◽  
Protein Kinase ◽  
Fatty Acid Metabolism ◽  
Acid Metabolism ◽  
Moderate Intensity ◽  
Amp Activated Protein Kinase

During moderate-intensity exercise, fatty acids are the predominant substrate for working skeletal muscle. The release of fatty acids from adipose tissue stores, combined with the ability of skeletal muscle to actively fine tune the gradient between fatty acid and carbohydrate metabolism, depending on substrate availability and energetic demands, requires a coordinated system of metabolic control. Over the past decade, since the discovery that AMP-activated protein kinase (AMPK) was increased in accordance with exercise intensity, there has been significant interest in the proposed role of this ancient stress-sensing kinase as a critical integrative switch controlling metabolic responses during exercise. In this review, studies examining the role of AMPK as a regulator of fatty acid metabolism in both adipose tissue and skeletal muscle during exercise will be discussed. Exercise induces activation of AMPK in adipocytes and regulates triglyceride hydrolysis and esterfication through phosphorylation of hormone sensitive lipase (HSL) and glycerol-3-phosphate acyl-transferase, respectively. In skeletal muscle, exercise-induced activation of AMPK is associated with increases in fatty acid uptake, phosphorylation of HSL, and increased fatty acid oxidation, which is thought to occur via the acetyl-CoA carboxylase-malony-CoA-CPT-1 signalling axis. Despite the importance of AMPK in regulating fatty acid metabolism under resting conditions, recent evidence from transgenic models of AMPK deficiency suggest that alternative signalling pathways may also be important for the control of fatty acid metabolism during exercise.

scholarly journals Arterio-venous balance studies of skeletal muscle fatty acid metabolism: what can we believe?

2013 ◽  
Vol 305 (8) ◽  
pp. E925-E930 ◽  
Author(s):  
ZengKui Guo ◽  
Michael D. Jensen
Keyword(s):  
Skeletal Muscle ◽  
Fatty Acids ◽  
Adipose Tissue ◽  
Fatty Acid ◽  
Fatty Acid Metabolism ◽  
Acid Metabolism ◽  
Healthy Humans ◽  
Venous Circulation ◽  
Complex Anatomy ◽  
Muscle Groups

The arterio-venous balance (A-V balance/difference) technique has been used by a number of groups, including ours, to study skeletal muscle fatty acid metabolism. Several lines of evidence indicate that, like glycogen, intramyocellular triglycerides (imcTG) are an energy source for local use. As such, the report that increased release of free fatty acids (FFA) via lipolysis from skeletal muscle, but not from adipose tissue, is responsible for the increased systemic lipolysis during IL-6 infusion in healthy humans is somewhat unexpected ( 26 ). It appears that given the complex anatomy of human limbs, as to be discussed in this review, it is virtually impossible to determine whether any fatty acids being released into the venous circulation of an arm or leg derive from the lipolysis of intermuscular fat residing between muscle groups, intramuscular fat residing within muscle groups (between epimysium and perimysium, or bundles), or the intramyocellular triglyceride droplets (imcTG). In many cases, it may even be difficult to be confident that there is no contribution of FFA from subcutaneous adipose tissue. This question is fundamentally important as one attempts to interpret the results of skeletal muscle fatty acid metabolism studies using the A-V balance technique. In this Perspectives article, we examine the reported results of fatty acid kinetics obtained using the techniques to evaluate the degree of and how to minimize contamination when attempting to sample skeletal muscle-specific fatty acids.

Inflammation, obesity, and fatty acid metabolism: influence ofn-3 polyunsaturated fatty acids on factors contributing to metabolic syndrome

2007 ◽  
Vol 32 (6) ◽  
pp. 1008-1024 ◽  
Author(s):  
Lindsay E. Robinson ◽  
Andrea C. Buchholz ◽  
Vera C. Mazurak
Keyword(s):  
Metabolic Syndrome ◽  
Fatty Acids ◽  
Fatty Acid ◽  
Polyunsaturated Fatty Acids ◽  
Abdominal Obesity ◽  
Fatty Acid Metabolism ◽  
Acid Metabolism ◽  
Preliminary Evidence ◽  
Postprandial Period

Metabolic syndrome (MetS) comprises an array of metabolic risk factors including abdominal obesity, dyslipidemia, hypertension, and glucose intolerance. Individuals with MetS are at elevated risk for diabetes and cardiovascular disease. Central to the etiology of MetS is an interrelated triad comprising inflammation, abdominal obesity, and aberrations in fatty acid metabolism, coupled with the more recently recognized changes in metabolism during the postprandial period. We review herein preliminary evidence regarding the role of dietary n-3 polyunsaturated fatty acids in modulating each of the components of the triad of adiposity, inflammation, and fatty acid metabolism, with particular attention to the role of the postprandial period as a contributor to the pathophysiology of MetS.

scholarly journals Reprogramming of fatty acid metabolism in cancer

2019 ◽  
Vol 122 (1) ◽  
pp. 4-22 ◽  
Author(s):  
Nikos Koundouros ◽  
George Poulogiannis
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Cancer Cells ◽  
Cancer Progression ◽  
Fatty Acid Metabolism ◽  
Acid Metabolism ◽  
De Novo ◽  
Great Promise ◽  
Molecular Heterogeneity

AbstractA common feature of cancer cells is their ability to rewire their metabolism to sustain the production of ATP and macromolecules needed for cell growth, division and survival. In particular, the importance of altered fatty acid metabolism in cancer has received renewed interest as, aside their principal role as structural components of the membrane matrix, they are important secondary messengers, and can also serve as fuel sources for energy production. In this review, we will examine the mechanisms through which cancer cells rewire their fatty acid metabolism with a focus on four main areas of research. (1) The role of de novo synthesis and exogenous uptake in the cellular pool of fatty acids. (2) The mechanisms through which molecular heterogeneity and oncogenic signal transduction pathways, such as PI3K–AKT–mTOR signalling, regulate fatty acid metabolism. (3) The role of fatty acids as essential mediators of cancer progression and metastasis, through remodelling of the tumour microenvironment. (4) Therapeutic strategies and considerations for successfully targeting fatty acid metabolism in cancer. Further research focusing on the complex interplay between oncogenic signalling and dysregulated fatty acid metabolism holds great promise to uncover novel metabolic vulnerabilities and improve the efficacy of targeted therapies.

Fatty acid metabolism in adipose tissue, muscle and liver in health and disease

2006 ◽  
Vol 42 ◽  
pp. 89-103 ◽  
Author(s):  
Keith N. Frayn ◽  
Peter Arner ◽  
Hannele Yki-Järvinen
Keyword(s):  
Skeletal Muscle ◽  
Adipose Tissue ◽  
Fatty Acid ◽  
Fatty Acid Metabolism ◽  
Acid Metabolism ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Very Low Density Lipoprotein ◽  
Low Density ◽  
Fat Mobilization

Fat is the largest energy reserve in mammals. Most tissues are involved in fatty acid metabolism, but three are quantitatively more important than others: adipose tissue, skeletal muscle and liver. Each of these tissues has a store of triacylglycerol that can be hydrolysed (mobilized) in a regulated way to release fatty acids. In the case of adipose tissue, these fatty acids may be released into the circulation for delivery to other tissues, whereas in muscle they are a substrate for oxidation and in liver they are a substrate for re-esterification within the endoplasmic reticulum to make triacylglycerol that will be secreted as very-low-density lipoprotein. These pathways are regulated, most clearly in the case of adipose tissue. Adipose tissue fat storage is stimulated, and fat mobilization suppressed, by insulin, leading to a drive to store energy in the fed state. Muscle fatty acid metabolism is more sensitive to physical activity, during which fatty acid utilization from extracellular and intracellular sources may increase enormously. The uptake of fat by the liver seems to depend mainly upon delivery in the plasma, but the secretion of very-low-density lipoprotein triacylglycerol is suppressed by insulin. There is clearly cooperation amongst the tissues, so that, for instance, adipose tissue fat mobilization increases to meet the demands of skeletal muscle during exercise. When triacylglycerol accumulates excessively in skeletal muscle and liver, sometimes called ectopic fat deposition, then the condition of insulin resistance arises. This may reflect a lack of exercise and an excess of fat intake.

Impaired fatty acid metabolism in type 2 diabetic skeletal muscle cells is reversed by PPARγ agonists

2005 ◽  
Vol 289 (1) ◽  
pp. E151-E159 ◽  
Author(s):  
Bong-Soo Cha ◽  
Theodore P. Ciaraldi ◽  
Kyong-Soo Park ◽  
Leslie Carter ◽  
Sunder R. Mudaliar ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Fatty Acids ◽  
Fatty Acid ◽  
Fatty Acid Metabolism ◽  
Acid Metabolism ◽  
Muscle Cells ◽  
Palmitate Oxidation ◽  
Pparγ Agonists ◽  
Type 2 Diabetic

The impact of type 2 diabetes on the ability of muscle to accumulate and dispose of fatty acids and triglycerides was evaluated in cultured muscle cells from nondiabetic (ND) and type 2 diabetic (T2D) subjects. In the presence of 5 μM palmitate, T2D muscle cells accumulated less lipid than ND cells (11.5 ± 1.2 vs. 15.1 ± 1.4 nmol/mg protein, P < 0.05). Chronic treatment (4 days) with the peroxisome proliferator-activated receptor-γ (PPARγ) agonist troglitazone increased palmitate accumulation, normalizing uptake in T2D cells. There were no significant differences between groups with regard to the relative incorporation of palmitate into neutral lipid species. This distribution was also unaffected by troglitazone treatment. β-Oxidation of both long-chain (palmitate) and medium-chain (octanoate) fatty acids in T2D muscle cells was reduced by ∼40% compared with ND cells. Palmitate oxidation occurred primarily in mitochondrial (∼40–50% of total) and peroxisomal (20–30%) compartments. The diabetes-related defect in palmitate oxidation was localized to the mitochondrial component. Both palmitate and octanoate oxidation were stimulated by a series of thiazolidinediones. Oxidation in T2D muscle cells was normalized after treatment. Troglitazone increased the mitochondrial component of palmitate oxidation. Skeletal muscle cells from T2D subjects express defects in free fatty acid metabolism that are retained in vitro, most importantly defects in β-oxidation. These defects can be corrected by treatment with PPARγ agonists. Augmentation of fatty acid disposal in skeletal muscle, potentially reducing intramyocellular triglyceride content, may represent one mechanism for the lipid-lowering and insulin-sensitizing effects of thiazolidinediones.

scholarly journals Polarization of Macrophages in Human Adipose Tissue is Related to the Fatty Acid Spectrum in Membrane Phospholipids

Nutrients ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 8 ◽  
Author(s):  
Rudolf Poledne ◽  
Hana Malinska ◽  
Hana Kubatova ◽  
Jiri Fronek ◽  
Filip Thieme ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Adipose Tissue ◽  
Fatty Acid ◽  
Cell Membrane ◽  
Fatty Acid Metabolism ◽  
Acid Metabolism ◽  
Human Adipose Tissue ◽  
Membrane Phospholipids ◽  
Anti Inflammatory ◽  
Inflammatory Macrophages

Residential macrophages in adipose tissue play a pivotal role in the development of inflammation not only within this tissue, but also affect the proinflammatory status of the whole body. Data on human adipose tissue inflammation and the role of macrophages are rather scarce. We previously documented that the proportion of proinflammatory macrophages in human adipose tissue correlates closely with non-HDL cholesterol concentrations. We hypothesized that this is due to the identical influence of diet on both parameters and decided to analyze the fatty acid spectrum in cell membrane phospholipids of the same individuals as a parameter of the diet consumed. Proinflammatory and anti-inflammatory macrophages were isolated from human adipose tissue (n = 43) and determined by flow cytometry as CD14+CD16+CD36high and CD14+CD16−CD163+, respectively. The spectrum of fatty acids in phospholipids in the cell membranes of specimens of the same adipose tissue was analyzed, and the proportion of proinflammatory macrophage increased with the proportions of palmitic and palmitoleic acids. Contrariwise, these macrophages decreased with increasing alpha-linolenic acid, total n-3 fatty acids, n-3/n-6 ratio, and eicosatetraenoic acid. A mirror picture was documented for the proportion of anti-inflammatory macrophages. The dietary score, obtained using a food frequency questionnaire, documented a positive relation to proinflammatory macrophages in individuals who consumed predominantly vegetable fat and fish, and individuals who consumed diets based on animal fat without fish and nut consumption. he present data support our hypothesis that macrophage polarization in human visceral adipose tissue is related to fatty acid metabolism, cell membrane composition, and diet consumed. It is suggested that fatty acid metabolism might participate also in inflammation and the risk of developing cardiovascular disease.

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