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White-to-brite conversion in human adipocytes promotes metabolic reprogramming towards fatty acid anabolic and catabolic pathways.

Barquissau V, Beuzelin D, Pisani DF, Beranger GE, Mairal A, Montagner A, Roussel B, Tavernier G, Marques MA, Moro C, Guillou H, Amri EZ, Langin D - Mol Metab (2016)

Bottom Line: This conversion is associated with transcriptional changes leading to major metabolic adaptations.Conversion of human white fat cells into brite adipocytes results in a major metabolic reprogramming inducing fatty acid anabolic and catabolic pathways.PDK4 redirects glucose from oxidation towards triglyceride synthesis and favors the use of fatty acids as energy source for uncoupling mitochondria.

View Article: PubMed Central - PubMed

Affiliation: INSERM, UMR 1048, Institute of Metabolic and Cardiovascular Diseases, Toulouse, France; University of Toulouse, Paul Sabatier University, France.

ABSTRACT

Objective: Fat depots with thermogenic activity have been identified in humans. In mice, the appearance of thermogenic adipocytes within white adipose depots (so-called brown-in-white i.e., brite or beige adipocytes) protects from obesity and insulin resistance. Brite adipocytes may originate from direct conversion of white adipocytes. The purpose of this work was to characterize the metabolism of human brite adipocytes.

Methods: Human multipotent adipose-derived stem cells were differentiated into white adipocytes and then treated with peroxisome proliferator-activated receptor (PPAR)γ or PPARα agonists between day 14 and day 18. Gene expression profiling was determined using DNA microarrays and RT-qPCR. Variations of mRNA levels were confirmed in differentiated human preadipocytes from primary cultures. Fatty acid and glucose metabolism was investigated using radiolabelled tracers, Western blot analyses and assessment of oxygen consumption. Pyruvate dehydrogenase kinase 4 (PDK4) knockdown was achieved using siRNA. In vivo, wild type and PPARα- mice were treated with a β3-adrenergic receptor agonist (CL316,243) to induce appearance of brite adipocytes in white fat depot. Determination of mRNA and protein levels was performed on inguinal white adipose tissue.

Results: PPAR agonists promote a conversion of white adipocytes into cells displaying a brite molecular pattern. This conversion is associated with transcriptional changes leading to major metabolic adaptations. Fatty acid anabolism i.e., fatty acid esterification into triglycerides, and catabolism i.e., lipolysis and fatty acid oxidation, are increased. Glucose utilization is redirected from oxidation towards glycerol-3-phophate production for triglyceride synthesis. This metabolic shift is dependent on the activation of PDK4 through inactivation of the pyruvate dehydrogenase complex. In vivo, PDK4 expression is markedly induced in wild-type mice in response to CL316,243, while this increase is blunted in PPARα- mice displaying an impaired britening response.

Conclusions: Conversion of human white fat cells into brite adipocytes results in a major metabolic reprogramming inducing fatty acid anabolic and catabolic pathways. PDK4 redirects glucose from oxidation towards triglyceride synthesis and favors the use of fatty acids as energy source for uncoupling mitochondria.

No MeSH data available.


Related in: MedlinePlus

Britening of white adipocytes induces anabolic and catabolic pathways of fat metabolism. Fatty acid metabolism was investigated in 18 day-differentiated hMADS cells treated or not with rosiglitazone or GW7647 for the last 4 days. (A) Fatty acid (oleate) incorporation into triglycerides (TG). (B) Gene expression level of glycerol kinase (GK). (C) Glycerol incorporation into triglycerides. (D) Glycerol release after stimulation by the β-adrenergic agonist, isoproterenol. (E) ATGL and HSL protein content. (F) Fatty acid (oleate) oxidation. (G) PLIN5 protein content. (H) Basal mitochondrial oxygen consumption rates (OCR) in the presence or not of 50 μM etomoxir. (I) OCR measured after addition of 200 μM oleate. Data represent mean ± SEM expressed as percentage of control (n = 7–12). Open bars: control cells (C), full bars: rosiglitazone-treated cells (R), hatched bars: GW7647-treated cells (GW). *: p < 0.05 for R or GW vs. C; **: p < 0.01; ***: p < 0.001. $$$: p < 0.001 for etomoxir vs. basal condition.
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fig2: Britening of white adipocytes induces anabolic and catabolic pathways of fat metabolism. Fatty acid metabolism was investigated in 18 day-differentiated hMADS cells treated or not with rosiglitazone or GW7647 for the last 4 days. (A) Fatty acid (oleate) incorporation into triglycerides (TG). (B) Gene expression level of glycerol kinase (GK). (C) Glycerol incorporation into triglycerides. (D) Glycerol release after stimulation by the β-adrenergic agonist, isoproterenol. (E) ATGL and HSL protein content. (F) Fatty acid (oleate) oxidation. (G) PLIN5 protein content. (H) Basal mitochondrial oxygen consumption rates (OCR) in the presence or not of 50 μM etomoxir. (I) OCR measured after addition of 200 μM oleate. Data represent mean ± SEM expressed as percentage of control (n = 7–12). Open bars: control cells (C), full bars: rosiglitazone-treated cells (R), hatched bars: GW7647-treated cells (GW). *: p < 0.05 for R or GW vs. C; **: p < 0.01; ***: p < 0.001. $$$: p < 0.001 for etomoxir vs. basal condition.

Mentions: Britening of hMADS adipocytes was associated with increased oleate incorporation into triglycerides as suggested by gene upregulation (Figure 2A, Figure S2A and Table S3). Newly activated fatty acids require glycerol-3-phosphate as a backbone for esterification. Glycerol kinase, an enzyme with higher expression in BAT than in WAT, showed strong induction in response to the treatments (Figure 2B). Accordingly, glycerol incorporation into triglycerides was enhanced (Figure 2C).


White-to-brite conversion in human adipocytes promotes metabolic reprogramming towards fatty acid anabolic and catabolic pathways.

Barquissau V, Beuzelin D, Pisani DF, Beranger GE, Mairal A, Montagner A, Roussel B, Tavernier G, Marques MA, Moro C, Guillou H, Amri EZ, Langin D - Mol Metab (2016)

Britening of white adipocytes induces anabolic and catabolic pathways of fat metabolism. Fatty acid metabolism was investigated in 18 day-differentiated hMADS cells treated or not with rosiglitazone or GW7647 for the last 4 days. (A) Fatty acid (oleate) incorporation into triglycerides (TG). (B) Gene expression level of glycerol kinase (GK). (C) Glycerol incorporation into triglycerides. (D) Glycerol release after stimulation by the β-adrenergic agonist, isoproterenol. (E) ATGL and HSL protein content. (F) Fatty acid (oleate) oxidation. (G) PLIN5 protein content. (H) Basal mitochondrial oxygen consumption rates (OCR) in the presence or not of 50 μM etomoxir. (I) OCR measured after addition of 200 μM oleate. Data represent mean ± SEM expressed as percentage of control (n = 7–12). Open bars: control cells (C), full bars: rosiglitazone-treated cells (R), hatched bars: GW7647-treated cells (GW). *: p < 0.05 for R or GW vs. C; **: p < 0.01; ***: p < 0.001. $$$: p < 0.001 for etomoxir vs. basal condition.
© Copyright Policy - CC BY-NC-ND
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4837301&req=5

fig2: Britening of white adipocytes induces anabolic and catabolic pathways of fat metabolism. Fatty acid metabolism was investigated in 18 day-differentiated hMADS cells treated or not with rosiglitazone or GW7647 for the last 4 days. (A) Fatty acid (oleate) incorporation into triglycerides (TG). (B) Gene expression level of glycerol kinase (GK). (C) Glycerol incorporation into triglycerides. (D) Glycerol release after stimulation by the β-adrenergic agonist, isoproterenol. (E) ATGL and HSL protein content. (F) Fatty acid (oleate) oxidation. (G) PLIN5 protein content. (H) Basal mitochondrial oxygen consumption rates (OCR) in the presence or not of 50 μM etomoxir. (I) OCR measured after addition of 200 μM oleate. Data represent mean ± SEM expressed as percentage of control (n = 7–12). Open bars: control cells (C), full bars: rosiglitazone-treated cells (R), hatched bars: GW7647-treated cells (GW). *: p < 0.05 for R or GW vs. C; **: p < 0.01; ***: p < 0.001. $$$: p < 0.001 for etomoxir vs. basal condition.
Mentions: Britening of hMADS adipocytes was associated with increased oleate incorporation into triglycerides as suggested by gene upregulation (Figure 2A, Figure S2A and Table S3). Newly activated fatty acids require glycerol-3-phosphate as a backbone for esterification. Glycerol kinase, an enzyme with higher expression in BAT than in WAT, showed strong induction in response to the treatments (Figure 2B). Accordingly, glycerol incorporation into triglycerides was enhanced (Figure 2C).

Bottom Line: This conversion is associated with transcriptional changes leading to major metabolic adaptations.Conversion of human white fat cells into brite adipocytes results in a major metabolic reprogramming inducing fatty acid anabolic and catabolic pathways.PDK4 redirects glucose from oxidation towards triglyceride synthesis and favors the use of fatty acids as energy source for uncoupling mitochondria.

View Article: PubMed Central - PubMed

Affiliation: INSERM, UMR 1048, Institute of Metabolic and Cardiovascular Diseases, Toulouse, France; University of Toulouse, Paul Sabatier University, France.

ABSTRACT

Objective: Fat depots with thermogenic activity have been identified in humans. In mice, the appearance of thermogenic adipocytes within white adipose depots (so-called brown-in-white i.e., brite or beige adipocytes) protects from obesity and insulin resistance. Brite adipocytes may originate from direct conversion of white adipocytes. The purpose of this work was to characterize the metabolism of human brite adipocytes.

Methods: Human multipotent adipose-derived stem cells were differentiated into white adipocytes and then treated with peroxisome proliferator-activated receptor (PPAR)γ or PPARα agonists between day 14 and day 18. Gene expression profiling was determined using DNA microarrays and RT-qPCR. Variations of mRNA levels were confirmed in differentiated human preadipocytes from primary cultures. Fatty acid and glucose metabolism was investigated using radiolabelled tracers, Western blot analyses and assessment of oxygen consumption. Pyruvate dehydrogenase kinase 4 (PDK4) knockdown was achieved using siRNA. In vivo, wild type and PPARα- mice were treated with a β3-adrenergic receptor agonist (CL316,243) to induce appearance of brite adipocytes in white fat depot. Determination of mRNA and protein levels was performed on inguinal white adipose tissue.

Results: PPAR agonists promote a conversion of white adipocytes into cells displaying a brite molecular pattern. This conversion is associated with transcriptional changes leading to major metabolic adaptations. Fatty acid anabolism i.e., fatty acid esterification into triglycerides, and catabolism i.e., lipolysis and fatty acid oxidation, are increased. Glucose utilization is redirected from oxidation towards glycerol-3-phophate production for triglyceride synthesis. This metabolic shift is dependent on the activation of PDK4 through inactivation of the pyruvate dehydrogenase complex. In vivo, PDK4 expression is markedly induced in wild-type mice in response to CL316,243, while this increase is blunted in PPARα- mice displaying an impaired britening response.

Conclusions: Conversion of human white fat cells into brite adipocytes results in a major metabolic reprogramming inducing fatty acid anabolic and catabolic pathways. PDK4 redirects glucose from oxidation towards triglyceride synthesis and favors the use of fatty acids as energy source for uncoupling mitochondria.

No MeSH data available.


Related in: MedlinePlus