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miR-155 regulates differentiation of brown and beige adipocytes via a bistable circuit.

Chen Y, Siegel F, Kipschull S, Haas B, Fröhlich H, Meister G, Pfeifer A - Nat Commun (2013)

Bottom Line: Brown adipocytes are a primary site of energy expenditure and reside not only in classical brown adipose tissue but can also be found in white adipose tissue.In contrast, transgenic overexpression of microRNA 155 in mice causes a reduction of brown adipose tissue mass and impairment of brown adipose tissue function.These data demonstrate that the bistable loop involving microRNA 155 and CCAAT/enhancer-binding protein β regulates brown lineage commitment, thereby, controlling the development of brown and beige fat cells.

View Article: PubMed Central - PubMed

Affiliation: Institute of Pharmacology and Toxicology, University of Bonn, Sigmund-Freud-Strasse 25, 53127 Bonn, Germany.

ABSTRACT
Brown adipocytes are a primary site of energy expenditure and reside not only in classical brown adipose tissue but can also be found in white adipose tissue. Here we show that microRNA 155 is enriched in brown adipose tissue and is highly expressed in proliferating brown preadipocytes but declines after induction of differentiation. Interestingly, microRNA 155 and its target, the adipogenic transcription factor CCAAT/enhancer-binding protein β, form a bistable feedback loop integrating hormonal signals that regulate proliferation or differentiation. Inhibition of microRNA 155 enhances brown adipocyte differentiation and induces a brown adipocyte-like phenotype ('browning') in white adipocytes. Consequently, microRNA 155-deficient mice exhibit increased brown adipose tissue function and 'browning' of white fat tissue. In contrast, transgenic overexpression of microRNA 155 in mice causes a reduction of brown adipose tissue mass and impairment of brown adipose tissue function. These data demonstrate that the bistable loop involving microRNA 155 and CCAAT/enhancer-binding protein β regulates brown lineage commitment, thereby, controlling the development of brown and beige fat cells.

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miR-155 impairs brown fat differentiation in vivo.(a) qRT–PCR analysis for miR-155 expression in igWAT and BAT of 10-week-old male mice. Expression in igWAT was set as one; n=3. (b) Schematic representation of the lentiviral construct (LVPGK-miR-155) used for generation of miR-155 transgenic (miR155TG) animals. For abbreviations, see Supplementary Fig. S1, PGK, phosphoglycerate 1 promoter. (c) Interscapular BAT isolated from 1-week-old wt or miR155TG mice. Bright field (left) and fluorescent images (right) are shown; GFP is co-expressed with miR-155 in transgenic mice; (scale bar =2 mm). (d) Hematoxylin and eosin staining of BAT sections from 1-week-old wt and miR155TG littermates; (scale bar =15 μm). (e) Western blot analysis of UCP1, PGC-1α, PPARγ and C/EBPβ expression in BAT isolated from 1-week-old wt and miR155TG littermates; each protein levels from three representative animals per group are shown. Tubulin served as loading control. (f) Densitometric quantification of UCP1, PGC-1α, PPARγ and C/EBPβ expression levels, normalized to tubulin. Data of the wt group were set as one; n=6 per group. (g) Infrared thermographic analysis of the body surface temperature in 4-day-old wt and miR155TG littermates. Three representative pairs are showed. (h) Statistical analysis of body surface temperature in wt and miR155TG littermates; wt: 34.75±0.39 °C; miR155TG: 33.24±0.53 °C; n=5 per group. (i) Interscapular BAT, igWAT, and visceral WAT (vWAT) were isolated from 10-week-old wt or miR155TG littermates. Scale bar, 3 mm (BAT); 4 mm (igWAT and vWAT). Two representative littermates are shown. (j) Statistics of BAT, igWAT, vWAT, spleen, heart, brain and liver weights relative to total body weight in 10-week-old wt and miR155TG littermates; n=3 per group. (k) qRT–PCR analysis of brown thermogenic/adipogenic genes in interscapular BAT of wt or miR155TG littermates at 10 weeks of age: UCP1, PGC-1α and PPARγ; n=3 per group. All data are presented as means±s.e.m. (*P<0.05; **P<0.01; n.s., not significant; Student’s t-test).
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f4: miR-155 impairs brown fat differentiation in vivo.(a) qRT–PCR analysis for miR-155 expression in igWAT and BAT of 10-week-old male mice. Expression in igWAT was set as one; n=3. (b) Schematic representation of the lentiviral construct (LVPGK-miR-155) used for generation of miR-155 transgenic (miR155TG) animals. For abbreviations, see Supplementary Fig. S1, PGK, phosphoglycerate 1 promoter. (c) Interscapular BAT isolated from 1-week-old wt or miR155TG mice. Bright field (left) and fluorescent images (right) are shown; GFP is co-expressed with miR-155 in transgenic mice; (scale bar =2 mm). (d) Hematoxylin and eosin staining of BAT sections from 1-week-old wt and miR155TG littermates; (scale bar =15 μm). (e) Western blot analysis of UCP1, PGC-1α, PPARγ and C/EBPβ expression in BAT isolated from 1-week-old wt and miR155TG littermates; each protein levels from three representative animals per group are shown. Tubulin served as loading control. (f) Densitometric quantification of UCP1, PGC-1α, PPARγ and C/EBPβ expression levels, normalized to tubulin. Data of the wt group were set as one; n=6 per group. (g) Infrared thermographic analysis of the body surface temperature in 4-day-old wt and miR155TG littermates. Three representative pairs are showed. (h) Statistical analysis of body surface temperature in wt and miR155TG littermates; wt: 34.75±0.39 °C; miR155TG: 33.24±0.53 °C; n=5 per group. (i) Interscapular BAT, igWAT, and visceral WAT (vWAT) were isolated from 10-week-old wt or miR155TG littermates. Scale bar, 3 mm (BAT); 4 mm (igWAT and vWAT). Two representative littermates are shown. (j) Statistics of BAT, igWAT, vWAT, spleen, heart, brain and liver weights relative to total body weight in 10-week-old wt and miR155TG littermates; n=3 per group. (k) qRT–PCR analysis of brown thermogenic/adipogenic genes in interscapular BAT of wt or miR155TG littermates at 10 weeks of age: UCP1, PGC-1α and PPARγ; n=3 per group. All data are presented as means±s.e.m. (*P<0.05; **P<0.01; n.s., not significant; Student’s t-test).

Mentions: Next, we analysed miR-155 expression in different fat depots. We found significantly higher levels of miR-155 in BAT compared with inguinal WAT (igWAT) (Fig. 4a). Similar to the in vitro situation, we found high levels of miR-155 in the SVF as well as in the purified (Sca1+/CD45−/Mac1−) precursors, whereas mature brown adipocytes exhibited a 2.6-fold reduction of miR-155 (Supplementary Fig. S5a,b).


miR-155 regulates differentiation of brown and beige adipocytes via a bistable circuit.

Chen Y, Siegel F, Kipschull S, Haas B, Fröhlich H, Meister G, Pfeifer A - Nat Commun (2013)

miR-155 impairs brown fat differentiation in vivo.(a) qRT–PCR analysis for miR-155 expression in igWAT and BAT of 10-week-old male mice. Expression in igWAT was set as one; n=3. (b) Schematic representation of the lentiviral construct (LVPGK-miR-155) used for generation of miR-155 transgenic (miR155TG) animals. For abbreviations, see Supplementary Fig. S1, PGK, phosphoglycerate 1 promoter. (c) Interscapular BAT isolated from 1-week-old wt or miR155TG mice. Bright field (left) and fluorescent images (right) are shown; GFP is co-expressed with miR-155 in transgenic mice; (scale bar =2 mm). (d) Hematoxylin and eosin staining of BAT sections from 1-week-old wt and miR155TG littermates; (scale bar =15 μm). (e) Western blot analysis of UCP1, PGC-1α, PPARγ and C/EBPβ expression in BAT isolated from 1-week-old wt and miR155TG littermates; each protein levels from three representative animals per group are shown. Tubulin served as loading control. (f) Densitometric quantification of UCP1, PGC-1α, PPARγ and C/EBPβ expression levels, normalized to tubulin. Data of the wt group were set as one; n=6 per group. (g) Infrared thermographic analysis of the body surface temperature in 4-day-old wt and miR155TG littermates. Three representative pairs are showed. (h) Statistical analysis of body surface temperature in wt and miR155TG littermates; wt: 34.75±0.39 °C; miR155TG: 33.24±0.53 °C; n=5 per group. (i) Interscapular BAT, igWAT, and visceral WAT (vWAT) were isolated from 10-week-old wt or miR155TG littermates. Scale bar, 3 mm (BAT); 4 mm (igWAT and vWAT). Two representative littermates are shown. (j) Statistics of BAT, igWAT, vWAT, spleen, heart, brain and liver weights relative to total body weight in 10-week-old wt and miR155TG littermates; n=3 per group. (k) qRT–PCR analysis of brown thermogenic/adipogenic genes in interscapular BAT of wt or miR155TG littermates at 10 weeks of age: UCP1, PGC-1α and PPARγ; n=3 per group. All data are presented as means±s.e.m. (*P<0.05; **P<0.01; n.s., not significant; Student’s t-test).
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f4: miR-155 impairs brown fat differentiation in vivo.(a) qRT–PCR analysis for miR-155 expression in igWAT and BAT of 10-week-old male mice. Expression in igWAT was set as one; n=3. (b) Schematic representation of the lentiviral construct (LVPGK-miR-155) used for generation of miR-155 transgenic (miR155TG) animals. For abbreviations, see Supplementary Fig. S1, PGK, phosphoglycerate 1 promoter. (c) Interscapular BAT isolated from 1-week-old wt or miR155TG mice. Bright field (left) and fluorescent images (right) are shown; GFP is co-expressed with miR-155 in transgenic mice; (scale bar =2 mm). (d) Hematoxylin and eosin staining of BAT sections from 1-week-old wt and miR155TG littermates; (scale bar =15 μm). (e) Western blot analysis of UCP1, PGC-1α, PPARγ and C/EBPβ expression in BAT isolated from 1-week-old wt and miR155TG littermates; each protein levels from three representative animals per group are shown. Tubulin served as loading control. (f) Densitometric quantification of UCP1, PGC-1α, PPARγ and C/EBPβ expression levels, normalized to tubulin. Data of the wt group were set as one; n=6 per group. (g) Infrared thermographic analysis of the body surface temperature in 4-day-old wt and miR155TG littermates. Three representative pairs are showed. (h) Statistical analysis of body surface temperature in wt and miR155TG littermates; wt: 34.75±0.39 °C; miR155TG: 33.24±0.53 °C; n=5 per group. (i) Interscapular BAT, igWAT, and visceral WAT (vWAT) were isolated from 10-week-old wt or miR155TG littermates. Scale bar, 3 mm (BAT); 4 mm (igWAT and vWAT). Two representative littermates are shown. (j) Statistics of BAT, igWAT, vWAT, spleen, heart, brain and liver weights relative to total body weight in 10-week-old wt and miR155TG littermates; n=3 per group. (k) qRT–PCR analysis of brown thermogenic/adipogenic genes in interscapular BAT of wt or miR155TG littermates at 10 weeks of age: UCP1, PGC-1α and PPARγ; n=3 per group. All data are presented as means±s.e.m. (*P<0.05; **P<0.01; n.s., not significant; Student’s t-test).
Mentions: Next, we analysed miR-155 expression in different fat depots. We found significantly higher levels of miR-155 in BAT compared with inguinal WAT (igWAT) (Fig. 4a). Similar to the in vitro situation, we found high levels of miR-155 in the SVF as well as in the purified (Sca1+/CD45−/Mac1−) precursors, whereas mature brown adipocytes exhibited a 2.6-fold reduction of miR-155 (Supplementary Fig. S5a,b).

Bottom Line: Brown adipocytes are a primary site of energy expenditure and reside not only in classical brown adipose tissue but can also be found in white adipose tissue.In contrast, transgenic overexpression of microRNA 155 in mice causes a reduction of brown adipose tissue mass and impairment of brown adipose tissue function.These data demonstrate that the bistable loop involving microRNA 155 and CCAAT/enhancer-binding protein β regulates brown lineage commitment, thereby, controlling the development of brown and beige fat cells.

View Article: PubMed Central - PubMed

Affiliation: Institute of Pharmacology and Toxicology, University of Bonn, Sigmund-Freud-Strasse 25, 53127 Bonn, Germany.

ABSTRACT
Brown adipocytes are a primary site of energy expenditure and reside not only in classical brown adipose tissue but can also be found in white adipose tissue. Here we show that microRNA 155 is enriched in brown adipose tissue and is highly expressed in proliferating brown preadipocytes but declines after induction of differentiation. Interestingly, microRNA 155 and its target, the adipogenic transcription factor CCAAT/enhancer-binding protein β, form a bistable feedback loop integrating hormonal signals that regulate proliferation or differentiation. Inhibition of microRNA 155 enhances brown adipocyte differentiation and induces a brown adipocyte-like phenotype ('browning') in white adipocytes. Consequently, microRNA 155-deficient mice exhibit increased brown adipose tissue function and 'browning' of white fat tissue. In contrast, transgenic overexpression of microRNA 155 in mice causes a reduction of brown adipose tissue mass and impairment of brown adipose tissue function. These data demonstrate that the bistable loop involving microRNA 155 and CCAAT/enhancer-binding protein β regulates brown lineage commitment, thereby, controlling the development of brown and beige fat cells.

Show MeSH
Related in: MedlinePlus