PGC-1β regulates the expression of mitochondrial genes involved in oxidative metabolism in white adipose tissue. Knockout of PGC-1β in adipocytes reduces the expression of genes related to the tricarboxylic acid cycle and oxidative phosphorylation, as well as levels of oxidative enzymes and mitochondrial DNA content. Rosiglitazone treatment increases mitochondrial gene expression and oxidative function in a PGC-1β-dependent manner. However, loss of PGC-1β and mitochondrial oxidative function in adipocytes does not induce whole-body or tissue-specific insulin resistance.

1. Study of the role of the PGC-1β transcriptional coactivator
in white adipose tissue and
its implication in the development of insulin resistance
Natàlia Enguix Elena
Laboratory of Metabolism and Obesity
Unit of Diabetes and Metabolism

2. White AdiposeTissue Thiazolidinediones
Adipogenesis
Mitochondrial Biogenesis
Oxidative Metabolism
Fatty acid uptake
Triglycerides accumulation
Lipid oxidation
Fatty acids
Insulin
Fatty acids IRS
ATP
PKC
Acyl-CoAs
STOP
Diacylglycerols
Ceramides

3. EXERCISE
COLD EXPOSURE
PGC-1
mtDNA replication/transcription
PGC-1
NRF1/2
TFAM
PGC-1
ERR Oxphos System
PGC-1
PPAR Fatty Acid Oxidation
Nucleus

4. Decreased mitochondrial mass and function in diabetic patients is associated with
low PGC-1 expression
Control Diabetic
Skeletal Muscle
(Patti et al, PNAS 2003)
Control Diabetic
PGC-1 mRNA Mitochondrial Mass
White Adipose Tissue
(Bogacka et al, Diabetes 2005)
No Diabetic Placebo Pioglitazone No Diabetic Placebo Pioglitazone
Control Control
Diabetic Diabetic

5. Expression of mitochondrial genes and mitochondrial biogenesis is not altered
in WAT of PGC-1-FAT-KO mice
loxP loxP
1 2 3 4 5 6 7 8 9 10 11 12 13 Floxed allele
+ aP2-Cre
1 2 3 6 7 8 9 10 11 12 13 PGC-1-FAT-KO
Gene Expression
1.6 Wildtype
mRNA (a.u.)
1.2 PGC-1-FAT-KO
0.8
0.4 ** **
0
Kidney Liver Testis Spleen Muscle Thymus BAT WAT
Gene Expression mtDNA
White Adipose Tissue
1,5 1,5
mRNA (a.u.)
1 1,0
a.u.
0,5 0,5
0 0,0
wt ko
Pardo et al. PLoS One (2011)

6. Rosiglitazone-induced mitochondrial biogenesis and function is independent of
PGC-1
Wt Cont. Wt Rosig. FAT-KO Cont. FAT-KO Rosig.
3.0 4.5
PGC-1 4.0
mRNA expression
2.5
mRNA expression
(Relative units)
3.5
(Relative units)
2.0 3.0
2.5
1.5
2.0
1.0 1.5
1.0
0.5
0.5
0 0
Wt FAT-KO COXII COXIV CYCS ATP5b CS ACO2 MCAD
2.5 3.5
Relative mtDNA content
mtDNA 3.0 Citrate synthase
2.0
mol/mg.min
2.5
1.5 CS activity
2.0
1.0 1.5
1.0
0.5
0.5
0 0
Cont. Rosig Cont. Rosig
Pardo et al. PLoS One (2011)

7. PGC-1β is highly expressed in mature white adipocytes
1,4 PGC-1β ATGL Pref-1 1
1,2 *
** 0,8
(Relative units)
1
(Relative units)
0,8
mRNA
0,6 PGC-1β
mRNA
0,6 PPARγ
*
0,4 Pref-1
0,4
0,2 0,2
0
0
Pre Conf Post d0 d2 d4 d6 d8
Days during differentation
2,5 Gene Expression
2
(Relative units)
1,5 Wild type + Vehicle
mRNA
Wild type + Rosiglitazone
1
0,5
0
NRF-2 NRF-1 ERRα ERRγ RIP140 PGC-1β

8. Generation of PGC-1β-FAT-KO mice
1 2 3 4 5 6 7 8 9 10 11 12 Floxed allele
+ aP2Cre
1 2 3 6 7 8 9 10 11 12 PGC-1β-FAT-KO
PGC-1β Expression 30ºC
1,6
1,4
1,2
mRNA (a.u.)
1
0,8 Wildtype
0,6 PGC-1B-FAT-KO
0,4 ** **
**
0,2
0
BAT iWAT Adipocytes Kidney Lungs Soleus Spleen Testis Thymus
Adipose tissues

9. Gene expression profiling in WAT of PGC-1β-FAT-KO mice
Microarray DNA
Wildtype Knockout
(n=5) (n=5)

10. PGC-1β regulates expression of genes involved in oxidative metabolism in white
adipose tissue
Gene Expression
1,4 White Adipose Tissue
1,2
(Relative units)
1
* * * ** *
mRNA
0,8 *
** * Wild type
0,6
* PGC-1β-FAT-KO
0,4
0,2
0
NDUFAB1 NDUFB9 SDHB CytC1 CytCs Cox5a Cox5b Cox7a1 ATP5a1 ATP5o
CI C II Cyt C C IV CV
OXPHOS
1,4
1,2
(Relative units)
1
* *
mRNA
0,8 * Wild type
* **
0,6 * *
* PGC-1β-FAT-KO
0,4
0,2
0
Aco2 Idh3a Idh3b MDH2 LDHB PGK1 Elovl6 Cpt1b Cidea Cideb
TCA Cycle Glycolysis Lipid Metabolism / Oxidation

11. PGC-1β-FAT-KO mice exhibit reduced levels of TCA cycle and OxPhos proteins
and impaired oxidative capacity in white adipose tissue
White Adipose Tissue
Wild type PGC-1β-FAT-KO
Citrate Synthase Cytochrome
Activity Oxidase Activity
Aconitase
0,2 0,03
ATPSynβ
μmole/mg/min
0,15
μmole/mg/min
NDUFB9 *
* 0,02
COX IV 0,1
SDHB 0,01
0,05
Cyt c
0 0
α-tubulin WT KO WT KO

12. Rosiglitazone-induced mitochondrial gene expression and function is mediated
by PGC-1β
4 Gene Expression
White Adipose Tissue
3 Wt + vehicle
mRNA (a.u.)
KO + vehicle
2
Wt + Rosiglitazone
**
*
** * * KO + Rosiglitazone
1 * *
** *
0
CoxIV Cox8b Cox7a1 CytCs ATPSynB Aco2 CS Cpt1b
Citrate Synthase Activity mtDNA Content
400 5
nmol/mg·min
300 4
3
a.u.
200 *
2
100 1
0 0
Vehicle Rosiglitazone Vehicle Rosiglitazone

13. Lack of PGC-1β in adipocytes does not induce whole body or tissue-specific insulin
resistance
Glucose Tolerance Test
450 Wt + Vehicle
KO + Vehicle
350
Glucose (mg/dL)
Wt + Rosiglitazone
KO + Rosiglitazone
250
150
50
0 20 40 60 80 100 120
Time (min)
Insulin Tolerance Test
150
Glucose (mg/dL)
100
50
0
0 20 40 60 80 100 120
Time (min)

14. Conclusions
 PGC-1β in white adipose tissue specifically regulates the expression of genes
involved in mitochondrial energy production.
 PGC-1β but not PGC-1α mediates the rosiglitazone-induced expression of
mitochondrial genes and the oxidative capacity of white adipose tissue.
 Full mitochondrial oxidative function is not required for the insulin-sensitizing
effects of thiazolidinediones.

15. Thank You
Metabolism and Obesity Laboratory

17. PGC-1β regulates mitochondrial gene expression in 3T3-L1 adipocytes
Gene expression
4 4
PGC-1α PGC-1β
3 3
mRNA (a.u.)
mRNA (a.u.)
2 2
1 ** ** 1 **
** ** ** ** **
0 0 Oxygen Consumption Rate
siControl: + - - - + - - - + - - - + - - - 3T3L1 Adipocytes
siPGC-1α: - + - + - + - + - + - + - + - + 7
siPGC-1β: - - + + - - + + - - + + - - + + DMSO P=0.16
6 Rosiglitazone P=0.11
DMSO Rosiglitazone DMSO Rosiglitazone
5
6 3
Relative Units
CytCs IDH3β 4
mRNA (a.u.)
mRNA (a.u.)
4 2 ** **
3
P=0.09
* ** **
2 1 ** ** 2
** **
1
0 0
0
3 3 + - - - + - - - + - - - + - - -
ATPSynβ NDUFB9 siControl:
- + - + - + - + - + - + - + - +
siPGC-1α:
mRNA (a.u.)
mRNA (a.u.)
2 siPGC-1β: - - + + - - + + - - + + - - + +
2
** ** ** Basal CCCP
1 ** ** 1 * ** **
0 0
siControl: + - - - + - - - + - - - + - - -
siPGC-1α: - + - + - + - + - + - + - + - +
siPGC-1β: - - + + - - + + - - + + - - + +
DMSO Rosiglitazone DMSO Rosiglitazone