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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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Related in: MedlinePlus

miR-155 regulates the recruitment of brite fat cells.(a) Oil Red O staining of fully differentiated WATs overexpressing miR-155 (LVmiR155) or an anti-miR-155 sponge (LVmiRS155) as compared with cells carrying a control scrambled miRNA (LVmiRctrl); mock, uninfected cells. (b) TG content of fully differentiated white adipocytes transduced with LVmiRctrl, LVmiR155 and LVmiRS155; mock, uninfected control. TG content was normalized to total protein concentration. Untreated cells were set as one. Data are represented as means±s.e.m. (*P<0.05; one-way analysis of variance (ANOVA); n=3). (c) qRT–PCR analysis of aP2, C/EBPα and PPARγ mRNA in fully differentiated white adipocytes transduced with indicated lentiviruses. Untreated cells were set as one. Data are presented as mean±s.e.m. (*P<0.05; one-way ANOVA; n=3). (d) qRT–PCR analysis of UCP1, PGC-1α and Cidea mRNA levels in differentiated white adipocytes transduced with LVC/EBPβ, LVmiR155, LVmiRS155 and LVmiRctrl or treated with 5 μM norepinephrine (NE). Differentiated BAT cells were used as positive control. Untreated white fat cells were set as one. Data were normalized to HPRT housekeeping gene expression and are represented as means±s.e.m. (*P<0.05; **P<0.01; ***P<0.001; one-way ANOVA; n=3). (e,f) Oil Red O staining (e) and qRT–PCR analysis (f) of UCP1, PGC-1α, Cidea, PPARγ, C/EBPα and aP2 mRNA of brown adipocytes (BAT cells) transduced with a low (60 ng RTase) or medium (180 ng RTase) dosage of control-miR (LVmiRctrl), miR-155 (LVmiR155) or anti-C/EBPβ siRNA (siC/EBPβ); mock, uninfected cells. Uninfected cells were set as one. Expression data are normalized to HPRT, and data are represented as means± s.e.m. (*P<0.05; one-way ANOVA; n=3). (g,h) Oil Red O staining (g) and qRT–PCR analysis (h) of UCP1, PGC-1α, Cidea, PPARγ, C/EBPα and aP2 mRNA of white adipocytes (WAT cells) transduced with with a low (60 ng RTase) or medium (180 ng RTase) dosage of control-miR (LVmiRctrl), miR-155 (LVmiR155) or anti-C/EBPβ siRNA (siC/EBPβ); mock, uninfected cells. Uninfected cells were set as one. Expression data are normalized to HPRT, and data are represented as means± s.e.m. (*P<0.05; one-way ANOVA; n=3). Scale bar, 3 mm.
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f5: miR-155 regulates the recruitment of brite fat cells.(a) Oil Red O staining of fully differentiated WATs overexpressing miR-155 (LVmiR155) or an anti-miR-155 sponge (LVmiRS155) as compared with cells carrying a control scrambled miRNA (LVmiRctrl); mock, uninfected cells. (b) TG content of fully differentiated white adipocytes transduced with LVmiRctrl, LVmiR155 and LVmiRS155; mock, uninfected control. TG content was normalized to total protein concentration. Untreated cells were set as one. Data are represented as means±s.e.m. (*P<0.05; one-way analysis of variance (ANOVA); n=3). (c) qRT–PCR analysis of aP2, C/EBPα and PPARγ mRNA in fully differentiated white adipocytes transduced with indicated lentiviruses. Untreated cells were set as one. Data are presented as mean±s.e.m. (*P<0.05; one-way ANOVA; n=3). (d) qRT–PCR analysis of UCP1, PGC-1α and Cidea mRNA levels in differentiated white adipocytes transduced with LVC/EBPβ, LVmiR155, LVmiRS155 and LVmiRctrl or treated with 5 μM norepinephrine (NE). Differentiated BAT cells were used as positive control. Untreated white fat cells were set as one. Data were normalized to HPRT housekeeping gene expression and are represented as means±s.e.m. (*P<0.05; **P<0.01; ***P<0.001; one-way ANOVA; n=3). (e,f) Oil Red O staining (e) and qRT–PCR analysis (f) of UCP1, PGC-1α, Cidea, PPARγ, C/EBPα and aP2 mRNA of brown adipocytes (BAT cells) transduced with a low (60 ng RTase) or medium (180 ng RTase) dosage of control-miR (LVmiRctrl), miR-155 (LVmiR155) or anti-C/EBPβ siRNA (siC/EBPβ); mock, uninfected cells. Uninfected cells were set as one. Expression data are normalized to HPRT, and data are represented as means± s.e.m. (*P<0.05; one-way ANOVA; n=3). (g,h) Oil Red O staining (g) and qRT–PCR analysis (h) of UCP1, PGC-1α, Cidea, PPARγ, C/EBPα and aP2 mRNA of white adipocytes (WAT cells) transduced with with a low (60 ng RTase) or medium (180 ng RTase) dosage of control-miR (LVmiRctrl), miR-155 (LVmiR155) or anti-C/EBPβ siRNA (siC/EBPβ); mock, uninfected cells. Uninfected cells were set as one. Expression data are normalized to HPRT, and data are represented as means± s.e.m. (*P<0.05; one-way ANOVA; n=3). Scale bar, 3 mm.

Mentions: To assess the effects of miR-155 on white fat cells, we isolated SVF cells from murine igWAT (Supplementary Fig. S7a) and overexpressed miR-155 using three different concentrations of LVmiR155 (60, 180 and 500 ng RTase). In addition, we knocked down miR-155 and C/EBPβ. Overexpression of miR-155 at high levels (500 ng RTase) significantly reduced lipid content (Fig. 5a and Supplementary Fig. S7b) and adipogenic marker levels in white adipocytes (Fig. 5c), whereas transduction with LVmiRS155 resulted in enhanced differentiation (Fig. 5b). Given the prominent effect of miR-155 on the development of the thermogenic program in brown adipocytes (Fig. 1g), we examined whether miR-155 might also have similar effects in WAT progenitors. Importantly, inhibition of endogenous miR-155 dramatically induced expression of UCP1 more than 20-fold (Fig. 5d and Supplementary Fig. S7c). Remarkably, the increase in UCP1 expression induced by the miR-155 sponge was even higher than the effect of norepinephrine, a well-known inducer of ‘browning’4, and was identical to the effect of C/EBPβ overexpression (Fig. 5d). Although PGC-1α and Cidea were almost undetectable in WAT, both were significantly increased by knockdown of miR-155 (Fig. 5d). In contrast, transduction with LVmiR155 further decreased the already low expression levels of UCP1 (Fig. 5d).


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 regulates the recruitment of brite fat cells.(a) Oil Red O staining of fully differentiated WATs overexpressing miR-155 (LVmiR155) or an anti-miR-155 sponge (LVmiRS155) as compared with cells carrying a control scrambled miRNA (LVmiRctrl); mock, uninfected cells. (b) TG content of fully differentiated white adipocytes transduced with LVmiRctrl, LVmiR155 and LVmiRS155; mock, uninfected control. TG content was normalized to total protein concentration. Untreated cells were set as one. Data are represented as means±s.e.m. (*P<0.05; one-way analysis of variance (ANOVA); n=3). (c) qRT–PCR analysis of aP2, C/EBPα and PPARγ mRNA in fully differentiated white adipocytes transduced with indicated lentiviruses. Untreated cells were set as one. Data are presented as mean±s.e.m. (*P<0.05; one-way ANOVA; n=3). (d) qRT–PCR analysis of UCP1, PGC-1α and Cidea mRNA levels in differentiated white adipocytes transduced with LVC/EBPβ, LVmiR155, LVmiRS155 and LVmiRctrl or treated with 5 μM norepinephrine (NE). Differentiated BAT cells were used as positive control. Untreated white fat cells were set as one. Data were normalized to HPRT housekeeping gene expression and are represented as means±s.e.m. (*P<0.05; **P<0.01; ***P<0.001; one-way ANOVA; n=3). (e,f) Oil Red O staining (e) and qRT–PCR analysis (f) of UCP1, PGC-1α, Cidea, PPARγ, C/EBPα and aP2 mRNA of brown adipocytes (BAT cells) transduced with a low (60 ng RTase) or medium (180 ng RTase) dosage of control-miR (LVmiRctrl), miR-155 (LVmiR155) or anti-C/EBPβ siRNA (siC/EBPβ); mock, uninfected cells. Uninfected cells were set as one. Expression data are normalized to HPRT, and data are represented as means± s.e.m. (*P<0.05; one-way ANOVA; n=3). (g,h) Oil Red O staining (g) and qRT–PCR analysis (h) of UCP1, PGC-1α, Cidea, PPARγ, C/EBPα and aP2 mRNA of white adipocytes (WAT cells) transduced with with a low (60 ng RTase) or medium (180 ng RTase) dosage of control-miR (LVmiRctrl), miR-155 (LVmiR155) or anti-C/EBPβ siRNA (siC/EBPβ); mock, uninfected cells. Uninfected cells were set as one. Expression data are normalized to HPRT, and data are represented as means± s.e.m. (*P<0.05; one-way ANOVA; n=3). Scale bar, 3 mm.
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Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC3644088&req=5

f5: miR-155 regulates the recruitment of brite fat cells.(a) Oil Red O staining of fully differentiated WATs overexpressing miR-155 (LVmiR155) or an anti-miR-155 sponge (LVmiRS155) as compared with cells carrying a control scrambled miRNA (LVmiRctrl); mock, uninfected cells. (b) TG content of fully differentiated white adipocytes transduced with LVmiRctrl, LVmiR155 and LVmiRS155; mock, uninfected control. TG content was normalized to total protein concentration. Untreated cells were set as one. Data are represented as means±s.e.m. (*P<0.05; one-way analysis of variance (ANOVA); n=3). (c) qRT–PCR analysis of aP2, C/EBPα and PPARγ mRNA in fully differentiated white adipocytes transduced with indicated lentiviruses. Untreated cells were set as one. Data are presented as mean±s.e.m. (*P<0.05; one-way ANOVA; n=3). (d) qRT–PCR analysis of UCP1, PGC-1α and Cidea mRNA levels in differentiated white adipocytes transduced with LVC/EBPβ, LVmiR155, LVmiRS155 and LVmiRctrl or treated with 5 μM norepinephrine (NE). Differentiated BAT cells were used as positive control. Untreated white fat cells were set as one. Data were normalized to HPRT housekeeping gene expression and are represented as means±s.e.m. (*P<0.05; **P<0.01; ***P<0.001; one-way ANOVA; n=3). (e,f) Oil Red O staining (e) and qRT–PCR analysis (f) of UCP1, PGC-1α, Cidea, PPARγ, C/EBPα and aP2 mRNA of brown adipocytes (BAT cells) transduced with a low (60 ng RTase) or medium (180 ng RTase) dosage of control-miR (LVmiRctrl), miR-155 (LVmiR155) or anti-C/EBPβ siRNA (siC/EBPβ); mock, uninfected cells. Uninfected cells were set as one. Expression data are normalized to HPRT, and data are represented as means± s.e.m. (*P<0.05; one-way ANOVA; n=3). (g,h) Oil Red O staining (g) and qRT–PCR analysis (h) of UCP1, PGC-1α, Cidea, PPARγ, C/EBPα and aP2 mRNA of white adipocytes (WAT cells) transduced with with a low (60 ng RTase) or medium (180 ng RTase) dosage of control-miR (LVmiRctrl), miR-155 (LVmiR155) or anti-C/EBPβ siRNA (siC/EBPβ); mock, uninfected cells. Uninfected cells were set as one. Expression data are normalized to HPRT, and data are represented as means± s.e.m. (*P<0.05; one-way ANOVA; n=3). Scale bar, 3 mm.
Mentions: To assess the effects of miR-155 on white fat cells, we isolated SVF cells from murine igWAT (Supplementary Fig. S7a) and overexpressed miR-155 using three different concentrations of LVmiR155 (60, 180 and 500 ng RTase). In addition, we knocked down miR-155 and C/EBPβ. Overexpression of miR-155 at high levels (500 ng RTase) significantly reduced lipid content (Fig. 5a and Supplementary Fig. S7b) and adipogenic marker levels in white adipocytes (Fig. 5c), whereas transduction with LVmiRS155 resulted in enhanced differentiation (Fig. 5b). Given the prominent effect of miR-155 on the development of the thermogenic program in brown adipocytes (Fig. 1g), we examined whether miR-155 might also have similar effects in WAT progenitors. Importantly, inhibition of endogenous miR-155 dramatically induced expression of UCP1 more than 20-fold (Fig. 5d and Supplementary Fig. S7c). Remarkably, the increase in UCP1 expression induced by the miR-155 sponge was even higher than the effect of norepinephrine, a well-known inducer of ‘browning’4, and was identical to the effect of C/EBPβ overexpression (Fig. 5d). Although PGC-1α and Cidea were almost undetectable in WAT, both were significantly increased by knockdown of miR-155 (Fig. 5d). In contrast, transduction with LVmiR155 further decreased the already low expression levels of UCP1 (Fig. 5d).

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