Fig. 1Effect of thyroid hormone (T3) treatment on small heterodimer partner (SHP) expression. Comparison of SHP expression in mouse liver (A, n=4 or n=5 in each group) after 6 hours or 5 days of thyroid hormone treatment (1 mg/g). Comparison of SHP expression in mouse primary hepatocytes (B) and human hepatoma cells (C) after 2 and 6 hours of T3 treatment (100 nmol/L). aSignificant differences compared to the control are P<0.05.
Fig. 2Effect of thyroid hormone (T3) on small heterodimer partner (SHP) promoter activity with or without thyroid hormone receptor (TR)/retinoid X receptor (RXR), and liver receptor homolog-1 (LRH-1). In each HepG2 cell sample, 300 ng of mouse SHP (A) or human SHP (B, C) promoter DNA was co-transfected with or without 75 ng of TRβ and 75 ng of RXRα or 75 ng of LRH-1. Vehicle or T3 (100 nmol/L) was administered for 24 hours to determine the effect of thyroid hormone on SHP promoter expression. Luciferase activity was measured and normalized to β-galactosidase activity. Significant differences compared to the control are aP<0.05 and bP<0.01.
Fig. 3Repression of expression from the 5' deletion small heterodimer partner (SHP) promoter by the thyroid hormone. The 200 ng of 5' human SHP promoter (full, -1490 and -175) was co-transfected with or without 100 ng of thyroid hormone receptor β (TRβ) and 30 ng of retinoid X receptor α (RXRα) or 100 ng of liver receptor homolog-1 (LRH-1) in 293 cells. Thyroid hormone (T3; 100 nmol/L) was added. Luciferase activity was measured and normalized against renilla activity. NS, not significant. Significant differences compared to the control aP<0.01.
Fig. 4Interaction between thyroid hormone (T3) and liver receptor homolog-1 (LRH-1). Electrophoretic mobility-shift assay was performed using an oligomer containing the LRH-1 responsive element (LRE) in the human SHP promoter (-518) as a probe and nuclear extracts of human hepatoma cells treated with 100 nmol/L of T3 for increasing times as indicated. For competition assays, unlabeled oligomers containing the hLRH-1(-518) LRE (self; lane 8), an LRE mutant (lane 9), or a consensus LRE (lane 10) were used in a 50-fold molar excess. MT, mutant.
Table 1Changes in Gene Expression after 5 Days of T3 Treatment in Mouse Liver
Gene symbol |
Gene description |
T3 treatment vs. control |
Log fold changea
|
T-score |
P value |
Bile acid synthesis |
|
|
|
|
CYP7A1 |
Cytochrome P450 7A |
1.008 |
3.477 |
0.025 |
CYP8B1 |
Sterol 12α-hydroxylase |
-0.364 |
-3.465 |
0.026 |
CYP27A1 |
Sterol 27-hydroxylase |
0.500 |
3.784 |
0.020 |
Nuclear receptors |
|
|
|
|
SHP |
Small heterodimer partner |
-0.698 |
-7.061 |
0.002 |
FXR |
Farnesoid X receptor |
0.152 |
1.624 |
0.176 |
LXRα |
Liver X receptor α |
0.465 |
2.266 |
0.083 |
TRβ |
Thyroid hormone receptor β |
0.119 |
1.423 |
0.225 |
HNF4α |
Hepatocyte nuclear receptor 4α |
-0.115 |
-1.955 |
0.118 |
LRH-1 |
Liver receptor homolog-1 |
-0.128 |
-1.623 |
0.177 |
Cholesterol metabolism |
|
|
|
|
HMG-CoA R |
3-Hydroxy-3-methylglutaryl-coenzyme A reductase |
1.516 |
3.935 |
0.018 |
HMG-CoA S1 |
3-Hydroxy-3-methylglutaryl-coenzyme A synthase 1 |
1.252 |
5.776 |
0.005 |
HMG-CoA S2 |
3-Hydroxy-3-methylglutaryl-coenzyme A synthase 2 |
0.074 |
0.699 |
0.529 |
SREBP1 |
Sterol regulatory element binding protein 1 |
-0.593 |
-2.543 |
0.062 |
VLDLR |
Very low density lipoprotein receptor |
-0.278 |
-1.301 |
0.262 |
SR-B1 |
Scavenger receptor |
-0.792 |
-4.942 |
0.009 |
APOA1 |
Apolipoprotein A1 |
0.201 |
5.047 |
0.007 |
APOB |
Apolipoprotein B |
0.077 |
0.158 |
0.884 |
APOE |
Apolipoprotein E |
-0.025 |
-0.864 |
0.440 |
LDLR |
Low density lipoprotein receptor |
0.386 |
1.007 |
0.373 |