scholarly journals γ-Linolenic acid increases expression of key regulators of lipid metabolism in human skeletal muscle cells

2019 ◽  
Author(s):  
L.A Baker ◽  
N.R.W Martin ◽  
D.J Player ◽  
M.P Lewis

AbstractControl of skeletal muscle fat metabolism is regulated acutely through Peroxisome Proliferator Activated Receptor (PPAR) δ activation and its downstream intracellular targets. The purpose of this study was to determine whether fatty acids with high binding affinity for PPARδ can elevate the expression of genes related to fatty acid oxidation and indicators of mitochondrial biogenesis in cultured human skeletal myotubes. Myotubes were treated for 72 hours with one of four conditions: (i) Control (CON); (ii) Eicosapentaenoic acid (EPA 250μM); (iii) γ-linolenic acid (γ-LA 250μM); (iv) PPARδ Agonist (GW501516 10nM). Incubation with γ-LA induced increases in the gene expression of CD36 (p= 0.005), HADHA (p= 0.022) and PDK4 (p=0.025) in comparison with CON, with no further differences observed between conditions. Furthermore, intensity of MitoTracker® Red immunostaining in myotubes increased following incubation with γ-LA (p≤ 0.001) and EPA (p= 0.005) however these trends were not mirrored in the expression of PGC-1α as might be expected. Overall, γ-LA elevates levels the transcription of key intracellular regulators of lipid metabolism and transport in human myotubes, which may be clinically beneficial in the control of metabolic diseases.

2004 ◽  
Vol 286 (2) ◽  
pp. E168-E175 ◽  
Author(s):  
Junlong Zhang ◽  
D. I. W. Phillips ◽  
Chunli Wang ◽  
Christopher D. Byrne

Peroxisome proliferator-activated receptor-α (PPARα) is a key regulator of fatty acid oxidation in skeletal muscle, but few data exist from humans in vivo. To investigate whether insulin sensitivity in skeletal muscle and body mass index (BMI) were associated with skeletal muscle expression of PPARα and with important genes regulating lipid metabolism in humans in vivo, we undertook hyperinsulinemic-euglycemic clamps and measured PPARα mRNA levels and mRNA levels of lipid regulating PPARα response genes in skeletal muscle biopsies. mRNA levels were measured in 16 men, using a novel highly sensitive and specific medium throughput quantitative competitive PCR that allows reproducible measurement of multiple candidate mRNAs simultaneously. mRNA levels of PPARα were positively correlated with mRNA levels of CD36 ( r = 0.77, P = 0.001), lipoprotein lipase ( r = 0.54, P = 0.024), muscle-type carnitine palmitoyltransferase-I ( r = 0.54, P = 0.024), uncoupling protein-2 ( r = 0.63, P = 0.008), and uncoupling protein-3 ( r = 0.53, P = 0.026), but not with measures of insulin sensitivity, BMI, or GLUT4, which plays an important role in insulin-mediated glucose uptake. Thus our data suggest that in humans skeletal muscle PPARα expression and genes regulating lipid metabolism are tightly linked, but there was no association between both insulin sensitivity and BMI with PPARα expression in skeletal muscle.


2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Nataša Nikolić ◽  
Magdalena Rhedin ◽  
Arild C. Rustan ◽  
Len Storlien ◽  
G. Hege Thoresen ◽  
...  

We investigated the effects of PGC-1α(peroxisome proliferator-activated receptorγcoactivator-1α) overexpression on the oxidative capacity of human skeletal muscle cellsex vivo. PGC-1αoverexpression increased the oxidation rate of palmitic acid and mRNA expression of genes regulating lipid metabolism, mitochondrial biogenesis, and function in human myotubes. Basal and insulin-stimulated deoxyglucose uptake were decreased, possibly due to upregulation of PDK4 mRNA. Expression of fast fiber-type gene marker (MHCIIa) was decreased. Compared to skeletal musclein vivo, PGC-1αoverexpression increased expression of several genes, which were downregulated during the process of cell isolation and culturing. In conclusion, PGC-1αoverexpression increased oxidative capacity of cultured myotubes by improving lipid metabolism, increasing expression of genes involved in regulation of mitochondrial function and biogenesis, and decreasing expression of MHCIIa. These results suggest that therapies aimed at increasing PGC-1αexpression may have utility in treatment of obesity and obesity-related diseases.


2020 ◽  
Vol 382 (3) ◽  
pp. 599-608
Author(s):  
Vigdis Aas ◽  
G. Hege Thoresen ◽  
Arild C. Rustan ◽  
Jenny Lund

AbstractPrimary human myotubes represent an alternative system to intact skeletal muscle for the study of human diseases related to changes in muscle energy metabolism. This work aimed to study if fatty acid and glucose metabolism in human myotubes in vitro were related to muscle of origin, donor gender, age, or body mass index (BMI). Myotubes from a total of 82 donors were established from three different skeletal muscles, i.e., musculus vastus lateralis, musculus obliquus internus abdominis, and musculi interspinales, and cellular energy metabolism was evaluated. Multiple linear regression analyses showed that donor age had a significant effect on glucose and oleic acid oxidation after correcting for gender, BMI, and muscle of origin. Donor BMI was the only significant contributor to cellular oleic acid uptake, whereas cellular glucose uptake did not rely on any of the variables examined. Despite the effect of age on substrate oxidation, cellular mRNA expression of pyruvate dehydrogenase kinase 4 (PDK4) and peroxisome proliferator–activated receptor gamma coactivator 1 alpha (PPARGC1A) did not correlate with donor age. In conclusion, donor age significantly impacts substrate oxidation in cultured human myotubes, whereas donor BMI affects cellular oleic acid uptake.


2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Elisa Benetti ◽  
Raffaella Mastrocola ◽  
Mara Rogazzo ◽  
Fausto Chiazza ◽  
Manuela Aragno ◽  
...  

Peroxisome Proliferator Activated Receptor (PPAR)-δagonists may serve for treating metabolic diseases. However, the effects of PPAR-δagonism within the skeletal muscle, which plays a key role in whole-body glucose metabolism, remain unclear. This study aimed to investigate the signaling pathways activated in the gastrocnemius muscle by chronic administration of the selective PPAR-δagonist, GW0742 (1 mg/kg/day for 16 weeks), in male C57Bl6/J mice treated for 30 weeks with high-fructose corn syrup (HFCS), the major sweetener in foods and soft-drinks (15% wt/vol in drinking water). Mice fed with the HFCS diet exhibited hyperlipidemia, hyperinsulinemia, hyperleptinemia, and hypoadiponectinemia. In the gastrocnemius muscle, HFCS impaired insulin and AMP-activated protein kinase signaling pathways and reduced GLUT-4 and GLUT-5 expression and membrane translocation. GW0742 administration induced PPAR-δupregulation and improvement in glucose and lipid metabolism. Diet-induced activation of nuclear factor-κB and expression of inducible-nitric-oxide-synthase and intercellular-adhesion-molecule-1 were attenuated by drug treatment. These effects were accompanied by reduction in the serum concentration of interleukin-6 and increase in muscular expression of fibroblast growth factor-21. Overall, here we show that PPAR-δactivation protects the skeletal muscle against the metabolic abnormalities caused by chronic HFCS exposure by affecting multiple levels of the insulin and inflammatory cascades.


Author(s):  
Ann Louise Olson

AbstractSkeletal muscle and adipose tissue play a major role in the regulation of whole-body glucose homeostasis. Much of the coordinated regulation of whole-body glucose homeostasis results from the regulation of lipid storage and release by adipose tissue and efficient switching between glucose oxidation and fatty acid oxidation in skeletal muscle. A control point for these biochemical actions center around the regulation of the insulin responsive glucose transporter, GLUT4. This review examines the regulation of GLUT4 in adipose tissue and skeletal muscle, in the context of the steroid nuclear hormone receptor signaling.


2017 ◽  
Vol 312 (5) ◽  
pp. E437-E446 ◽  
Author(s):  
Svenia Schnyder ◽  
Kristoffer Svensson ◽  
Bettina Cardel ◽  
Christoph Handschin

Low-carbohydrate/high-fat (LCHF) diets are increasingly popular dietary interventions for body weight control and as treatment for different pathological conditions. However, the mechanisms of action are still poorly understood, in particular, in long-term administration. Besides liver, brain, and heart, skeletal muscle is one of the major organs involved in the regulation of physiological and pathophysiological ketosis. We assessed the role of the peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) in skeletal muscle of male wild-type control and PGC-1α muscle-specific knockout mice upon 12 wk of LCHF diet feeding. Interestingly, LCHF diet administration increased oxygen consumption in a muscle PGC-1α-dependent manner, concomitant with a blunted transcriptional induction of genes involved in fatty acid oxidation and impairment in exercise performance. These data reveal a new role for muscle PGC-1α in regulating the physiological adaptation to long-term LCHF diet administration.


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