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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

PPARγ and PPARα agonists promote britening of human white adipocytes. (A) Gene expression levels of thermogenic genes. (B) UCP1 protein content. Gene expression levels of (C) brown-, (D) brite- and (E) white-specific markers. (F) PLIN1 protein content. (G) Pictures representative of Oil Red O staining in each condition at day 18. Intracellular triglyceride (TG) content quantified by enzymatic assay. (H) mRNA levels of thermogenic genes in human adipocytes differentiated in primary culture. Data represent mean ± SEM expressed as percentage of control (n = 6–12) for hMADS cells and (n = 2–4) for primary adipocytes. 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.
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fig1: PPARγ and PPARα agonists promote britening of human white adipocytes. (A) Gene expression levels of thermogenic genes. (B) UCP1 protein content. Gene expression levels of (C) brown-, (D) brite- and (E) white-specific markers. (F) PLIN1 protein content. (G) Pictures representative of Oil Red O staining in each condition at day 18. Intracellular triglyceride (TG) content quantified by enzymatic assay. (H) mRNA levels of thermogenic genes in human adipocytes differentiated in primary culture. Data represent mean ± SEM expressed as percentage of control (n = 6–12) for hMADS cells and (n = 2–4) for primary adipocytes. 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.

Mentions: Treatments with PPARγ (Rosi) or PPARα (GW) agonists added for 4 days on differentiated white adipocytes (Figure S1A) increased UCP1 mRNA and protein levels (15- and 11-fold increase, respectively) (Figure 1A,B), as well as expression of genes classically elevated in brown and brite fat cells (CIDEA, CPT1b, ELOVL3, PGC1α) (Figure 1A). We next determined whether PPAR agonist-treated adipocytes expressed brown- and brite-specific markers. Brown markers were not (MPZL and LHX8) expressed or were weakly (ZIC1) expressed and not regulated by treatments (Figure 1C and data not shown). By contrast, expression of brite adipocyte markers TMEM26, TBX1 and CITED1 was increased (Figure 1D). Altogether, these data indicate that upon PPARγ or PPARα activation, hMADS white adipocytes display a molecular pattern of brite fat cells.


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)

PPARγ and PPARα agonists promote britening of human white adipocytes. (A) Gene expression levels of thermogenic genes. (B) UCP1 protein content. Gene expression levels of (C) brown-, (D) brite- and (E) white-specific markers. (F) PLIN1 protein content. (G) Pictures representative of Oil Red O staining in each condition at day 18. Intracellular triglyceride (TG) content quantified by enzymatic assay. (H) mRNA levels of thermogenic genes in human adipocytes differentiated in primary culture. Data represent mean ± SEM expressed as percentage of control (n = 6–12) for hMADS cells and (n = 2–4) for primary adipocytes. 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.
© Copyright Policy - CC BY-NC-ND
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4837301&req=5

fig1: PPARγ and PPARα agonists promote britening of human white adipocytes. (A) Gene expression levels of thermogenic genes. (B) UCP1 protein content. Gene expression levels of (C) brown-, (D) brite- and (E) white-specific markers. (F) PLIN1 protein content. (G) Pictures representative of Oil Red O staining in each condition at day 18. Intracellular triglyceride (TG) content quantified by enzymatic assay. (H) mRNA levels of thermogenic genes in human adipocytes differentiated in primary culture. Data represent mean ± SEM expressed as percentage of control (n = 6–12) for hMADS cells and (n = 2–4) for primary adipocytes. 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.
Mentions: Treatments with PPARγ (Rosi) or PPARα (GW) agonists added for 4 days on differentiated white adipocytes (Figure S1A) increased UCP1 mRNA and protein levels (15- and 11-fold increase, respectively) (Figure 1A,B), as well as expression of genes classically elevated in brown and brite fat cells (CIDEA, CPT1b, ELOVL3, PGC1α) (Figure 1A). We next determined whether PPAR agonist-treated adipocytes expressed brown- and brite-specific markers. Brown markers were not (MPZL and LHX8) expressed or were weakly (ZIC1) expressed and not regulated by treatments (Figure 1C and data not shown). By contrast, expression of brite adipocyte markers TMEM26, TBX1 and CITED1 was increased (Figure 1D). Altogether, these data indicate that upon PPARγ or PPARα activation, hMADS white adipocytes display a molecular pattern of brite fat cells.

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