Adipogenesis is differentially impaired by thyroid hormone receptor mutant isoforms

Alok Mishra, Xu Guang Zhu, Kai Ge, Sheue Yann Cheng

Research output: Contribution to journalArticle

Abstract

To understand the roles of thyroid hormone receptors (TRs) in adipogenesis, we adopted a loss-of-function approach. We generated 3T3-L1 cells stably expressing either TRα1 mutant (TRα1PV) or TRβ1 mutant (TRβ1PV). TRα1PV and TRβ1PV are dominant negative mutations with a frameshift in the C-terminal amino acids. In control cells, the thyroid hormone, tri-iodothyronine (T3), induced a 2.5-fold increase in adipogenesis in 3T3-L1 cells, as demonstrated by increased lipid droplets. This increase was mediated by T3-induced expression of the peroxisome proliferator-activated receptor γ (PPARγ) and CCAAT/enhancer-binding protein α (C/EBPα), which are master regulators of adipogenesis at both the mRNA and protein levels. In 3T3-L1 cells stably expressing TRα1PV (L1-α1PV cells) or TRβ1PV (L1-β1PV cells), adipogenesis was reduced 94 or 54% respectively, indicative of differential inhibitory activity of mutant TR isoforms. Concordantly, the expression of PPARγ and C/EBPα at the mRNA and protein levels was more repressed in L1-α1PV cells than in L1-β1PV cells. In addition, the expression of PPARγ downstream target genes involved in fatty acid synthesis - the lipoprotein lipase (Lpl) and aP2 involved in adipogenesis - was more inhibited by TRα1PV than by TRβ1PV. Chromatin immunoprecipitation assays showed that TRα1PV was more avidly recruited than TRβ1PV to the promoter to preferentially block the expression of the C/ebpα gene. Taken together, these data indicate that impaired adipogenesis by mutant TR is isoform dependent. The finding that induction of adipogenesis is differentially regulated by TR isoforms suggests that TR isoform-specific ligands could be designed for therapeutic intervention for lipid abnormalities.

Original languageEnglish (US)
Pages (from-to)247-255
Number of pages9
JournalJournal of Molecular Endocrinology
Volume44
Issue number4
DOIs
StatePublished - Apr 2010
Externally publishedYes

Fingerprint

Thyroid Hormone Receptors
Adipogenesis
Protein Isoforms
3T3-L1 Cells
Peroxisome Proliferator-Activated Receptors
CCAAT-Enhancer-Binding Proteins
Messenger RNA
Lipoprotein Lipase
Chromatin Immunoprecipitation
Thyroid Hormones
Genes
Proteins
Fatty Acids
Ligands
Lipids
Amino Acids
Mutation

ASJC Scopus subject areas

  • Endocrinology
  • Molecular Biology

Cite this

Adipogenesis is differentially impaired by thyroid hormone receptor mutant isoforms. / Mishra, Alok; Zhu, Xu Guang; Ge, Kai; Cheng, Sheue Yann.

In: Journal of Molecular Endocrinology, Vol. 44, No. 4, 04.2010, p. 247-255.

Research output: Contribution to journalArticle

Mishra, Alok ; Zhu, Xu Guang ; Ge, Kai ; Cheng, Sheue Yann. / Adipogenesis is differentially impaired by thyroid hormone receptor mutant isoforms. In: Journal of Molecular Endocrinology. 2010 ; Vol. 44, No. 4. pp. 247-255.
@article{212e47412c2e402288c6f3435457b4da,
title = "Adipogenesis is differentially impaired by thyroid hormone receptor mutant isoforms",
abstract = "To understand the roles of thyroid hormone receptors (TRs) in adipogenesis, we adopted a loss-of-function approach. We generated 3T3-L1 cells stably expressing either TRα1 mutant (TRα1PV) or TRβ1 mutant (TRβ1PV). TRα1PV and TRβ1PV are dominant negative mutations with a frameshift in the C-terminal amino acids. In control cells, the thyroid hormone, tri-iodothyronine (T3), induced a 2.5-fold increase in adipogenesis in 3T3-L1 cells, as demonstrated by increased lipid droplets. This increase was mediated by T3-induced expression of the peroxisome proliferator-activated receptor γ (PPARγ) and CCAAT/enhancer-binding protein α (C/EBPα), which are master regulators of adipogenesis at both the mRNA and protein levels. In 3T3-L1 cells stably expressing TRα1PV (L1-α1PV cells) or TRβ1PV (L1-β1PV cells), adipogenesis was reduced 94 or 54{\%} respectively, indicative of differential inhibitory activity of mutant TR isoforms. Concordantly, the expression of PPARγ and C/EBPα at the mRNA and protein levels was more repressed in L1-α1PV cells than in L1-β1PV cells. In addition, the expression of PPARγ downstream target genes involved in fatty acid synthesis - the lipoprotein lipase (Lpl) and aP2 involved in adipogenesis - was more inhibited by TRα1PV than by TRβ1PV. Chromatin immunoprecipitation assays showed that TRα1PV was more avidly recruited than TRβ1PV to the promoter to preferentially block the expression of the C/ebpα gene. Taken together, these data indicate that impaired adipogenesis by mutant TR is isoform dependent. The finding that induction of adipogenesis is differentially regulated by TR isoforms suggests that TR isoform-specific ligands could be designed for therapeutic intervention for lipid abnormalities.",
author = "Alok Mishra and Zhu, {Xu Guang} and Kai Ge and Cheng, {Sheue Yann}",
year = "2010",
month = "4",
doi = "10.1677/JME-09-0137",
language = "English (US)",
volume = "44",
pages = "247--255",
journal = "Journal of Molecular Endocrinology",
issn = "0952-5041",
publisher = "Society for Endocrinology",
number = "4",

}

TY - JOUR

T1 - Adipogenesis is differentially impaired by thyroid hormone receptor mutant isoforms

AU - Mishra, Alok

AU - Zhu, Xu Guang

AU - Ge, Kai

AU - Cheng, Sheue Yann

PY - 2010/4

Y1 - 2010/4

N2 - To understand the roles of thyroid hormone receptors (TRs) in adipogenesis, we adopted a loss-of-function approach. We generated 3T3-L1 cells stably expressing either TRα1 mutant (TRα1PV) or TRβ1 mutant (TRβ1PV). TRα1PV and TRβ1PV are dominant negative mutations with a frameshift in the C-terminal amino acids. In control cells, the thyroid hormone, tri-iodothyronine (T3), induced a 2.5-fold increase in adipogenesis in 3T3-L1 cells, as demonstrated by increased lipid droplets. This increase was mediated by T3-induced expression of the peroxisome proliferator-activated receptor γ (PPARγ) and CCAAT/enhancer-binding protein α (C/EBPα), which are master regulators of adipogenesis at both the mRNA and protein levels. In 3T3-L1 cells stably expressing TRα1PV (L1-α1PV cells) or TRβ1PV (L1-β1PV cells), adipogenesis was reduced 94 or 54% respectively, indicative of differential inhibitory activity of mutant TR isoforms. Concordantly, the expression of PPARγ and C/EBPα at the mRNA and protein levels was more repressed in L1-α1PV cells than in L1-β1PV cells. In addition, the expression of PPARγ downstream target genes involved in fatty acid synthesis - the lipoprotein lipase (Lpl) and aP2 involved in adipogenesis - was more inhibited by TRα1PV than by TRβ1PV. Chromatin immunoprecipitation assays showed that TRα1PV was more avidly recruited than TRβ1PV to the promoter to preferentially block the expression of the C/ebpα gene. Taken together, these data indicate that impaired adipogenesis by mutant TR is isoform dependent. The finding that induction of adipogenesis is differentially regulated by TR isoforms suggests that TR isoform-specific ligands could be designed for therapeutic intervention for lipid abnormalities.

AB - To understand the roles of thyroid hormone receptors (TRs) in adipogenesis, we adopted a loss-of-function approach. We generated 3T3-L1 cells stably expressing either TRα1 mutant (TRα1PV) or TRβ1 mutant (TRβ1PV). TRα1PV and TRβ1PV are dominant negative mutations with a frameshift in the C-terminal amino acids. In control cells, the thyroid hormone, tri-iodothyronine (T3), induced a 2.5-fold increase in adipogenesis in 3T3-L1 cells, as demonstrated by increased lipid droplets. This increase was mediated by T3-induced expression of the peroxisome proliferator-activated receptor γ (PPARγ) and CCAAT/enhancer-binding protein α (C/EBPα), which are master regulators of adipogenesis at both the mRNA and protein levels. In 3T3-L1 cells stably expressing TRα1PV (L1-α1PV cells) or TRβ1PV (L1-β1PV cells), adipogenesis was reduced 94 or 54% respectively, indicative of differential inhibitory activity of mutant TR isoforms. Concordantly, the expression of PPARγ and C/EBPα at the mRNA and protein levels was more repressed in L1-α1PV cells than in L1-β1PV cells. In addition, the expression of PPARγ downstream target genes involved in fatty acid synthesis - the lipoprotein lipase (Lpl) and aP2 involved in adipogenesis - was more inhibited by TRα1PV than by TRβ1PV. Chromatin immunoprecipitation assays showed that TRα1PV was more avidly recruited than TRβ1PV to the promoter to preferentially block the expression of the C/ebpα gene. Taken together, these data indicate that impaired adipogenesis by mutant TR is isoform dependent. The finding that induction of adipogenesis is differentially regulated by TR isoforms suggests that TR isoform-specific ligands could be designed for therapeutic intervention for lipid abnormalities.

UR - http://www.scopus.com/inward/record.url?scp=77950228944&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=77950228944&partnerID=8YFLogxK

U2 - 10.1677/JME-09-0137

DO - 10.1677/JME-09-0137

M3 - Article

C2 - 20080985

AN - SCOPUS:77950228944

VL - 44

SP - 247

EP - 255

JO - Journal of Molecular Endocrinology

JF - Journal of Molecular Endocrinology

SN - 0952-5041

IS - 4

ER -