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Up-regulation of mitochondrial activity and acquirement of brown adipose tissue-like property in the white adipose tissue of fsp27 deficient mice.

Toh SY, Gong J, Du G, Li JZ, Yang S, Ye J, Yao H, Zhang Y, Xue B, Li Q, Yang H, Wen Z, Li P - PLoS ONE (2008)

Bottom Line: Fsp27, a member of the Cide family proteins, was shown to localize to lipid droplet and promote lipid storage in adipocytes.We further demonstrated that BAT-specific genes and key metabolic controlling factors such as FoxC2, PPAR and PGC1alpha were all markedly upregulated.Remarkably, Fsp27(-/-) MEFs differentiated in vitro show many brown adipocyte characteristics in the presence of the thyroid hormone triiodothyronine (T3).

View Article: PubMed Central - PubMed

Affiliation: Institute of Molecular and Cell Biology, Singapore.

ABSTRACT
Fsp27, a member of the Cide family proteins, was shown to localize to lipid droplet and promote lipid storage in adipocytes. We aimed to understand the biological role of Fsp27 in regulating adipose tissue differentiation, insulin sensitivity and energy balance. Fsp27(-/-) mice and Fsp27/lep double deficient mice were generated and we examined the adiposity, whole body metabolism, BAT and WAT morphology, insulin sensitivity, mitochondrial activity, and gene expression changes in these mouse strains. Furthermore, we isolated mouse embryonic fibroblasts (MEFs) from wildtype and Fsp27(-/-) mice, followed by their differentiation into adipocytes in vitro. We found that Fsp27 is expressed in both brown adipose tissue (BAT) and white adipose tissue (WAT) and its levels were significantly elevated in the WAT and liver of leptin-deficient ob/ob mice. Fsp27(-/-) mice had increased energy expenditure, lower levels of plasma triglycerides and free fatty acids. Furthermore, Fsp27(-/-)and Fsp27/lep double-deficient mice are resistant to diet-induced obesity and display increased insulin sensitivity. Moreover, white adipocytes in Fsp27(-/-) mice have reduced triglycerides accumulation and smaller lipid droplets, while levels of mitochondrial proteins, mitochondrial size and activity are dramatically increased. We further demonstrated that BAT-specific genes and key metabolic controlling factors such as FoxC2, PPAR and PGC1alpha were all markedly upregulated. In contrast, factors inhibiting BAT differentiation such as Rb, p107 and RIP140 were down-regulated in the WAT of Fsp27(-/-) mice. Remarkably, Fsp27(-/-) MEFs differentiated in vitro show many brown adipocyte characteristics in the presence of the thyroid hormone triiodothyronine (T3). Our data thus suggest that Fsp27 acts as a novel regulator in vivo to control WAT identity, mitochondrial activity and insulin sensitivity.

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Fsp27 expression in mice tissue and the morphology of WAT and BAT in Fsp27−/− mice.A. Tissue distributions of Fsp27 protein by western blot analysis. SI, small intestine; BAT, brown adipose tissue; GWAT, gonadal white adipose tissue; SM, skeletal muscle. β-tubulin was used as a loading control. B. Fsp27 is expressed in differentiated 3T3-L1 adipocytes. FABP (fatty acid binding protein) is used as an adipocyte differentiation marker. Day 0 represents undifferentiated 3T3-L1 fibroblasts. . C. Elevated Fsp27 protein levels in the WAT and liver of leptin deficient (ob/ob) mice. WT, wild type. D. Indirect immunofluorescence showing co-localization of Fsp27 with perilipin (Plin) on lipid droplet surface in Day 8 post differentiated 3T3-L1 cells. E & F. Genotype analyses by PCR (E) and western blot (F) assays using tail genomic DNA and gonadal white adipose tissue (GWAT) lysate, respectively. +/+, +/−, −/− represent wild-type, Fsp27 heterozygous and homozygous mice, respectively. G & H. Morphology of WAT and BAT of wild type and Fsp27−/− mice. HE, hemotoxylin and eosin staining. EM, electron microscope image. 3 months old mice were used for the experiments. LD, lipid droplets; N, nuclei. Scale bar = 25 µm and 1 µm for HE and EM, respectively. .
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pone-0002890-g001: Fsp27 expression in mice tissue and the morphology of WAT and BAT in Fsp27−/− mice.A. Tissue distributions of Fsp27 protein by western blot analysis. SI, small intestine; BAT, brown adipose tissue; GWAT, gonadal white adipose tissue; SM, skeletal muscle. β-tubulin was used as a loading control. B. Fsp27 is expressed in differentiated 3T3-L1 adipocytes. FABP (fatty acid binding protein) is used as an adipocyte differentiation marker. Day 0 represents undifferentiated 3T3-L1 fibroblasts. . C. Elevated Fsp27 protein levels in the WAT and liver of leptin deficient (ob/ob) mice. WT, wild type. D. Indirect immunofluorescence showing co-localization of Fsp27 with perilipin (Plin) on lipid droplet surface in Day 8 post differentiated 3T3-L1 cells. E & F. Genotype analyses by PCR (E) and western blot (F) assays using tail genomic DNA and gonadal white adipose tissue (GWAT) lysate, respectively. +/+, +/−, −/− represent wild-type, Fsp27 heterozygous and homozygous mice, respectively. G & H. Morphology of WAT and BAT of wild type and Fsp27−/− mice. HE, hemotoxylin and eosin staining. EM, electron microscope image. 3 months old mice were used for the experiments. LD, lipid droplets; N, nuclei. Scale bar = 25 µm and 1 µm for HE and EM, respectively. .

Mentions: To determine the precise tissue distribution of Fsp27, we generated polyclonal antibody against Fsp27 and evaluated its expression profile by western blot analysis. High levels of Fsp27 protein were detected in WAT and moderate levels in BAT. No Fsp27 protein was detected in other tissues such as liver, kidney, colon and skeletal muscle (SM) (Fig. 1A). Fsp27 was also detected in NIH3T3 L1 adipocytes after 4 days differentiation and its levels remain high during the course of differentiation (Fig. 1B). These data suggest that Fsp27 is rather exclusively expressed at high levels in adipose tissue including BAT and WAT. The specific expression of Fsp27 in adipose tissue prompted us to check whether levels of Fsp27 protein were correlated with the development of obesity by examining the levels of Fsp27 in the WAT of leptin-deficient ob/ob mice. As shown in Fig. 1C, levels of Fsp27 in WAT were dramatically elevated in ob/ob mice compared with that of wild type mice. Furthermore, higher levels of Fsp27 were detected in the liver of ob/ob mice that contains large amount of lipid droplets. Using Fsp27 antibody, we checked the sub-cellular localization of Fsp27 in differentiated 3T3-L1 cells and observed that a fraction of Fsp27 was co-localized with lipid droplet specific marker Perilipin (Fig. 1D), consistent with previous observation that overexpression of GFP-Fsp27 fusion protein is targeted to lipid droplet [31], [32]. These data suggest that Fsp27 may positively correlate with the development of obesity and the accumulation of lipid in WAT and hepatocytes.


Up-regulation of mitochondrial activity and acquirement of brown adipose tissue-like property in the white adipose tissue of fsp27 deficient mice.

Toh SY, Gong J, Du G, Li JZ, Yang S, Ye J, Yao H, Zhang Y, Xue B, Li Q, Yang H, Wen Z, Li P - PLoS ONE (2008)

Fsp27 expression in mice tissue and the morphology of WAT and BAT in Fsp27−/− mice.A. Tissue distributions of Fsp27 protein by western blot analysis. SI, small intestine; BAT, brown adipose tissue; GWAT, gonadal white adipose tissue; SM, skeletal muscle. β-tubulin was used as a loading control. B. Fsp27 is expressed in differentiated 3T3-L1 adipocytes. FABP (fatty acid binding protein) is used as an adipocyte differentiation marker. Day 0 represents undifferentiated 3T3-L1 fibroblasts. . C. Elevated Fsp27 protein levels in the WAT and liver of leptin deficient (ob/ob) mice. WT, wild type. D. Indirect immunofluorescence showing co-localization of Fsp27 with perilipin (Plin) on lipid droplet surface in Day 8 post differentiated 3T3-L1 cells. E & F. Genotype analyses by PCR (E) and western blot (F) assays using tail genomic DNA and gonadal white adipose tissue (GWAT) lysate, respectively. +/+, +/−, −/− represent wild-type, Fsp27 heterozygous and homozygous mice, respectively. G & H. Morphology of WAT and BAT of wild type and Fsp27−/− mice. HE, hemotoxylin and eosin staining. EM, electron microscope image. 3 months old mice were used for the experiments. LD, lipid droplets; N, nuclei. Scale bar = 25 µm and 1 µm for HE and EM, respectively. .
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2483355&req=5

pone-0002890-g001: Fsp27 expression in mice tissue and the morphology of WAT and BAT in Fsp27−/− mice.A. Tissue distributions of Fsp27 protein by western blot analysis. SI, small intestine; BAT, brown adipose tissue; GWAT, gonadal white adipose tissue; SM, skeletal muscle. β-tubulin was used as a loading control. B. Fsp27 is expressed in differentiated 3T3-L1 adipocytes. FABP (fatty acid binding protein) is used as an adipocyte differentiation marker. Day 0 represents undifferentiated 3T3-L1 fibroblasts. . C. Elevated Fsp27 protein levels in the WAT and liver of leptin deficient (ob/ob) mice. WT, wild type. D. Indirect immunofluorescence showing co-localization of Fsp27 with perilipin (Plin) on lipid droplet surface in Day 8 post differentiated 3T3-L1 cells. E & F. Genotype analyses by PCR (E) and western blot (F) assays using tail genomic DNA and gonadal white adipose tissue (GWAT) lysate, respectively. +/+, +/−, −/− represent wild-type, Fsp27 heterozygous and homozygous mice, respectively. G & H. Morphology of WAT and BAT of wild type and Fsp27−/− mice. HE, hemotoxylin and eosin staining. EM, electron microscope image. 3 months old mice were used for the experiments. LD, lipid droplets; N, nuclei. Scale bar = 25 µm and 1 µm for HE and EM, respectively. .
Mentions: To determine the precise tissue distribution of Fsp27, we generated polyclonal antibody against Fsp27 and evaluated its expression profile by western blot analysis. High levels of Fsp27 protein were detected in WAT and moderate levels in BAT. No Fsp27 protein was detected in other tissues such as liver, kidney, colon and skeletal muscle (SM) (Fig. 1A). Fsp27 was also detected in NIH3T3 L1 adipocytes after 4 days differentiation and its levels remain high during the course of differentiation (Fig. 1B). These data suggest that Fsp27 is rather exclusively expressed at high levels in adipose tissue including BAT and WAT. The specific expression of Fsp27 in adipose tissue prompted us to check whether levels of Fsp27 protein were correlated with the development of obesity by examining the levels of Fsp27 in the WAT of leptin-deficient ob/ob mice. As shown in Fig. 1C, levels of Fsp27 in WAT were dramatically elevated in ob/ob mice compared with that of wild type mice. Furthermore, higher levels of Fsp27 were detected in the liver of ob/ob mice that contains large amount of lipid droplets. Using Fsp27 antibody, we checked the sub-cellular localization of Fsp27 in differentiated 3T3-L1 cells and observed that a fraction of Fsp27 was co-localized with lipid droplet specific marker Perilipin (Fig. 1D), consistent with previous observation that overexpression of GFP-Fsp27 fusion protein is targeted to lipid droplet [31], [32]. These data suggest that Fsp27 may positively correlate with the development of obesity and the accumulation of lipid in WAT and hepatocytes.

Bottom Line: Fsp27, a member of the Cide family proteins, was shown to localize to lipid droplet and promote lipid storage in adipocytes.We further demonstrated that BAT-specific genes and key metabolic controlling factors such as FoxC2, PPAR and PGC1alpha were all markedly upregulated.Remarkably, Fsp27(-/-) MEFs differentiated in vitro show many brown adipocyte characteristics in the presence of the thyroid hormone triiodothyronine (T3).

View Article: PubMed Central - PubMed

Affiliation: Institute of Molecular and Cell Biology, Singapore.

ABSTRACT
Fsp27, a member of the Cide family proteins, was shown to localize to lipid droplet and promote lipid storage in adipocytes. We aimed to understand the biological role of Fsp27 in regulating adipose tissue differentiation, insulin sensitivity and energy balance. Fsp27(-/-) mice and Fsp27/lep double deficient mice were generated and we examined the adiposity, whole body metabolism, BAT and WAT morphology, insulin sensitivity, mitochondrial activity, and gene expression changes in these mouse strains. Furthermore, we isolated mouse embryonic fibroblasts (MEFs) from wildtype and Fsp27(-/-) mice, followed by their differentiation into adipocytes in vitro. We found that Fsp27 is expressed in both brown adipose tissue (BAT) and white adipose tissue (WAT) and its levels were significantly elevated in the WAT and liver of leptin-deficient ob/ob mice. Fsp27(-/-) mice had increased energy expenditure, lower levels of plasma triglycerides and free fatty acids. Furthermore, Fsp27(-/-)and Fsp27/lep double-deficient mice are resistant to diet-induced obesity and display increased insulin sensitivity. Moreover, white adipocytes in Fsp27(-/-) mice have reduced triglycerides accumulation and smaller lipid droplets, while levels of mitochondrial proteins, mitochondrial size and activity are dramatically increased. We further demonstrated that BAT-specific genes and key metabolic controlling factors such as FoxC2, PPAR and PGC1alpha were all markedly upregulated. In contrast, factors inhibiting BAT differentiation such as Rb, p107 and RIP140 were down-regulated in the WAT of Fsp27(-/-) mice. Remarkably, Fsp27(-/-) MEFs differentiated in vitro show many brown adipocyte characteristics in the presence of the thyroid hormone triiodothyronine (T3). Our data thus suggest that Fsp27 acts as a novel regulator in vivo to control WAT identity, mitochondrial activity and insulin sensitivity.

Show MeSH
Related in: MedlinePlus