Limits...
Role of extrathyroidal TSHR expression in adipocyte differentiation and its association with obesity.

Lu S, Guan Q, Liu Y, Wang H, Xu W, Li X, Fu Y, Gao L, Zhao J, Wang X - Lipids Health Dis (2012)

Bottom Line: Finally, the TSHR expression in adipose tissues was determined in 120 patients.The results showed that TSHR expression in subcutaneous adipose tissue is correlated with BMI (body mass index).Taken together, these results suggested that TSHR is an important regulator of adipocyte differentiation.

View Article: PubMed Central - HTML - PubMed

Affiliation: The Institute of Cell Biology, Shandong University School of Medicine, Jinan, China, 250012.

ABSTRACT

Background: Obesity is known to be associated with higher risks of cardiovascular disease, metabolic syndrome, and diabetes mellitus. Thyroid-stimulating hormone (TSHR) is the receptor for thyroid-stimulating hormone (TSH, or thyrotropin), the key regulator of thyroid functions. The expression of TSHR, once considered to be limited to thyrocytes, has been so far detected in many extrathyroidal tissues including liver and fat. Previous studies have shown that TSHR expression is upregulated when preadipocytes differentiate into mature adipocytes, suggestive of a possible role of TSHR in adipogenesis. However, it remains unclear whether TSHR expression in adipocytes is implicated in the pathogenesis of obesity.

Methods: In the present study, TSHR expression in adipose tissues from both mice and human was analyzed, and its association with obesity was evaluated.

Results: We here showed that TSHR expression was increased at both mRNA and protein levels when 3T3-L1 preadipocytes were induced to differentiate. Knockdown of TSHR blocked the adipocyte differentiation of 3T3-L1 preadipocytes as evaluated by Oil-red-O staining for lipid accumulation and by RT-PCR analyses of PPAR-γ and ALBP mRNA expression. We generated obesity mice (C57/BL6) by high-fat diet feeding and found that the TSHR protein expression in visceral adipose tissues from obesity mice was significantly higher in comparison with the non-obesity control mice (P < 0.05). Finally, the TSHR expression in adipose tissues was determined in 120 patients. The results showed that TSHR expression in subcutaneous adipose tissue is correlated with BMI (body mass index).

Conclusion: Taken together, these results suggested that TSHR is an important regulator of adipocyte differentiation. Dysregulated expression of TSHR in adipose tissues is associated with obesity, which may involve a mechanism of excess adipogenesis.

Show MeSH

Related in: MedlinePlus

Adipose differentiation of 3T3-L1 preadipocytes. Adipose differentiation of 3T3-L1 preadipocytes was induced as described in Materials and Methods. (A) Adipose differentiation of 3T3-L1 preadipocytes evaluated by Oil-red-O staining of lipid droplets. (B) Quantitative analysis of the intracellular Oil-red-O by spectrophotometry. (C) PPAR-γ and ALBP mRNA expression at different stages of 3T3-L1 preadipoytes differentiation. (D) Quantitative analyses of PPAR-γ and ALBP mRNA levels at different stages of 3T3-L1 preadipoytes differentiation. Each experiment was repeated at least three times. *P < 0.05 vs. preadipocytes before induction.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3285521&req=5

Figure 1: Adipose differentiation of 3T3-L1 preadipocytes. Adipose differentiation of 3T3-L1 preadipocytes was induced as described in Materials and Methods. (A) Adipose differentiation of 3T3-L1 preadipocytes evaluated by Oil-red-O staining of lipid droplets. (B) Quantitative analysis of the intracellular Oil-red-O by spectrophotometry. (C) PPAR-γ and ALBP mRNA expression at different stages of 3T3-L1 preadipoytes differentiation. (D) Quantitative analyses of PPAR-γ and ALBP mRNA levels at different stages of 3T3-L1 preadipoytes differentiation. Each experiment was repeated at least three times. *P < 0.05 vs. preadipocytes before induction.

Mentions: 3T3-L1 preadipocytes were induced to differentiate as described in Materials and Methods. The differentiation was evaluated by Oil-red-O staining for lipid accumulation and by RT-PCR analyses of PPAR-γ and ALBP mRNA expression. As shown in Figure 1 (A, B), lipid droplets could be detected by Oil-red-O staining as early as day-4 post differentiation induction, and peaked on day-12. To further verify the preadipocyte differentiation, the expression of PPAR-γ and ALBP, two essential regulators and markers for adipocyte differentiation, was analyzed by RT-PCR. As shown in Figure 1(C, D), the mRNA levels of PPAR-γ and ALBP were significantly increased on day-2 post induction of differentiation, and peaked on day-12 (P < 0.05).


Role of extrathyroidal TSHR expression in adipocyte differentiation and its association with obesity.

Lu S, Guan Q, Liu Y, Wang H, Xu W, Li X, Fu Y, Gao L, Zhao J, Wang X - Lipids Health Dis (2012)

Adipose differentiation of 3T3-L1 preadipocytes. Adipose differentiation of 3T3-L1 preadipocytes was induced as described in Materials and Methods. (A) Adipose differentiation of 3T3-L1 preadipocytes evaluated by Oil-red-O staining of lipid droplets. (B) Quantitative analysis of the intracellular Oil-red-O by spectrophotometry. (C) PPAR-γ and ALBP mRNA expression at different stages of 3T3-L1 preadipoytes differentiation. (D) Quantitative analyses of PPAR-γ and ALBP mRNA levels at different stages of 3T3-L1 preadipoytes differentiation. Each experiment was repeated at least three times. *P < 0.05 vs. preadipocytes before induction.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3285521&req=5

Figure 1: Adipose differentiation of 3T3-L1 preadipocytes. Adipose differentiation of 3T3-L1 preadipocytes was induced as described in Materials and Methods. (A) Adipose differentiation of 3T3-L1 preadipocytes evaluated by Oil-red-O staining of lipid droplets. (B) Quantitative analysis of the intracellular Oil-red-O by spectrophotometry. (C) PPAR-γ and ALBP mRNA expression at different stages of 3T3-L1 preadipoytes differentiation. (D) Quantitative analyses of PPAR-γ and ALBP mRNA levels at different stages of 3T3-L1 preadipoytes differentiation. Each experiment was repeated at least three times. *P < 0.05 vs. preadipocytes before induction.
Mentions: 3T3-L1 preadipocytes were induced to differentiate as described in Materials and Methods. The differentiation was evaluated by Oil-red-O staining for lipid accumulation and by RT-PCR analyses of PPAR-γ and ALBP mRNA expression. As shown in Figure 1 (A, B), lipid droplets could be detected by Oil-red-O staining as early as day-4 post differentiation induction, and peaked on day-12. To further verify the preadipocyte differentiation, the expression of PPAR-γ and ALBP, two essential regulators and markers for adipocyte differentiation, was analyzed by RT-PCR. As shown in Figure 1(C, D), the mRNA levels of PPAR-γ and ALBP were significantly increased on day-2 post induction of differentiation, and peaked on day-12 (P < 0.05).

Bottom Line: Finally, the TSHR expression in adipose tissues was determined in 120 patients.The results showed that TSHR expression in subcutaneous adipose tissue is correlated with BMI (body mass index).Taken together, these results suggested that TSHR is an important regulator of adipocyte differentiation.

View Article: PubMed Central - HTML - PubMed

Affiliation: The Institute of Cell Biology, Shandong University School of Medicine, Jinan, China, 250012.

ABSTRACT

Background: Obesity is known to be associated with higher risks of cardiovascular disease, metabolic syndrome, and diabetes mellitus. Thyroid-stimulating hormone (TSHR) is the receptor for thyroid-stimulating hormone (TSH, or thyrotropin), the key regulator of thyroid functions. The expression of TSHR, once considered to be limited to thyrocytes, has been so far detected in many extrathyroidal tissues including liver and fat. Previous studies have shown that TSHR expression is upregulated when preadipocytes differentiate into mature adipocytes, suggestive of a possible role of TSHR in adipogenesis. However, it remains unclear whether TSHR expression in adipocytes is implicated in the pathogenesis of obesity.

Methods: In the present study, TSHR expression in adipose tissues from both mice and human was analyzed, and its association with obesity was evaluated.

Results: We here showed that TSHR expression was increased at both mRNA and protein levels when 3T3-L1 preadipocytes were induced to differentiate. Knockdown of TSHR blocked the adipocyte differentiation of 3T3-L1 preadipocytes as evaluated by Oil-red-O staining for lipid accumulation and by RT-PCR analyses of PPAR-γ and ALBP mRNA expression. We generated obesity mice (C57/BL6) by high-fat diet feeding and found that the TSHR protein expression in visceral adipose tissues from obesity mice was significantly higher in comparison with the non-obesity control mice (P < 0.05). Finally, the TSHR expression in adipose tissues was determined in 120 patients. The results showed that TSHR expression in subcutaneous adipose tissue is correlated with BMI (body mass index).

Conclusion: Taken together, these results suggested that TSHR is an important regulator of adipocyte differentiation. Dysregulated expression of TSHR in adipose tissues is associated with obesity, which may involve a mechanism of excess adipogenesis.

Show MeSH
Related in: MedlinePlus