Limits...
Thyroid-stimulating hormone inhibits adipose triglyceride lipase in 3T3-L1 adipocytes through the PKA pathway.

Jiang D, Ma S, Jing F, Xu C, Yan F, Wang A, Zhao J - PLoS ONE (2015)

Bottom Line: The inhibitory effects of TSH on ATGL expression were abolished by H89, which is a protein kinase A (PKA) inhibitor.These results indicate that TSH has an inhibitory effect on ATGL expression in mature adipocytes.The associated mechanism is related to PKA activation.

View Article: PubMed Central - PubMed

Affiliation: Department of Endocrinology and Metabolism, Shandong Provincial Hospital affiliated to Shandong University, Jinan, Shandong, China; Department of Endocrinology and Metabolism, The Second Hospital of Shandong University, Jinan, Shandong, China.

ABSTRACT
Thyroid-stimulating hormone (TSH) has been shown to play an important role in the regulation of triglyceride (TG) metabolism in adipose tissue. Adipose triglyceride lipase (ATGL) is a rate-limiting enzyme controlling the hydrolysis of TG. Thus far, it is unclear whether TSH has a direct effect on the expression of ATGL. Because TSH function is mediated through the TSH receptor (TSHR), TSHR knockout mice (Tshr-/- mice) (supplemented with thyroxine) were used in this study to determine the effects of TSHR deletion on ATGL expression. These effects were verified in 3T3-L1 adipocytes and potential underlying mechanisms were explored. In the Tshr-/- mice, ATGL expression in epididymal adipose tissue was significantly increased compared with that in Tshr+/+ mice. ATGL expression was observed to increase with the differentiation process of 3T3-L1 preadipocytes. In mature 3T3-L1 adipocytes, TSH significantly suppressed ATGL expression at both the protein and mRNA levels in a dose-dependent manner. Forskolin, which is an activator of adenylate cyclase, suppressed the expression of ATGL in 3T3-L1 adipocytes. The inhibitory effects of TSH on ATGL expression were abolished by H89, which is a protein kinase A (PKA) inhibitor. These results indicate that TSH has an inhibitory effect on ATGL expression in mature adipocytes. The associated mechanism is related to PKA activation.

Show MeSH

Related in: MedlinePlus

TSH decreased ATGL expression in mature differentiated cells.(A) On D12, the cells were treated with 0.1 μM bTSH, 1 μM bTSH or 2 μM bTSH for 24 h or 48 h in serum-starved DMEM. Proteins were separated by SDS-PAGE and immunoblotted for ATGL and GAPDH. Values are quantified by densitometry and normalized with GAPDH. Representative Western blot results are shown. (B) Total RNA was extracted from differentiated cells treated with 2 μM bTSH for 48 h in serum-free DMEM. ATGL mRNA levels were determined by real-time PCR and normalized with β-actin. Values are reported as the fold change relative to the control group. The data are from 3 independent experiments and are presented as the mean ± SD. ** p < 0.01 versus the control group. Original magnification: 400×.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4295851&req=5

pone.0116439.g003: TSH decreased ATGL expression in mature differentiated cells.(A) On D12, the cells were treated with 0.1 μM bTSH, 1 μM bTSH or 2 μM bTSH for 24 h or 48 h in serum-starved DMEM. Proteins were separated by SDS-PAGE and immunoblotted for ATGL and GAPDH. Values are quantified by densitometry and normalized with GAPDH. Representative Western blot results are shown. (B) Total RNA was extracted from differentiated cells treated with 2 μM bTSH for 48 h in serum-free DMEM. ATGL mRNA levels were determined by real-time PCR and normalized with β-actin. Values are reported as the fold change relative to the control group. The data are from 3 independent experiments and are presented as the mean ± SD. ** p < 0.01 versus the control group. Original magnification: 400×.

Mentions: Next, we explored the effect of TSH on ATGL expression in the differentiated 3T3-L1 cells. Fully differentiated 3T3-L1 cells were treated in the absence or presence of bTSH for 24 h and 48 h. ATGL expression was determined by Western blotting and RT-PCR, respectively. As shown in Fig. 3A, and Fig. 3B, TSH inhibited ATGL protein expression and mRNA expression. The reductions of ATGL expression in the 3T3-L1 cells were approximately 30%, 60% and 60% following treatment with 0.1 μM, 1 μM and 2 μM TSH, respectively. These results confirmed that TSH directly decreased the expression of ATGL in the mature 3T3-L1 cells.


Thyroid-stimulating hormone inhibits adipose triglyceride lipase in 3T3-L1 adipocytes through the PKA pathway.

Jiang D, Ma S, Jing F, Xu C, Yan F, Wang A, Zhao J - PLoS ONE (2015)

TSH decreased ATGL expression in mature differentiated cells.(A) On D12, the cells were treated with 0.1 μM bTSH, 1 μM bTSH or 2 μM bTSH for 24 h or 48 h in serum-starved DMEM. Proteins were separated by SDS-PAGE and immunoblotted for ATGL and GAPDH. Values are quantified by densitometry and normalized with GAPDH. Representative Western blot results are shown. (B) Total RNA was extracted from differentiated cells treated with 2 μM bTSH for 48 h in serum-free DMEM. ATGL mRNA levels were determined by real-time PCR and normalized with β-actin. Values are reported as the fold change relative to the control group. The data are from 3 independent experiments and are presented as the mean ± SD. ** p < 0.01 versus the control group. Original magnification: 400×.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4295851&req=5

pone.0116439.g003: TSH decreased ATGL expression in mature differentiated cells.(A) On D12, the cells were treated with 0.1 μM bTSH, 1 μM bTSH or 2 μM bTSH for 24 h or 48 h in serum-starved DMEM. Proteins were separated by SDS-PAGE and immunoblotted for ATGL and GAPDH. Values are quantified by densitometry and normalized with GAPDH. Representative Western blot results are shown. (B) Total RNA was extracted from differentiated cells treated with 2 μM bTSH for 48 h in serum-free DMEM. ATGL mRNA levels were determined by real-time PCR and normalized with β-actin. Values are reported as the fold change relative to the control group. The data are from 3 independent experiments and are presented as the mean ± SD. ** p < 0.01 versus the control group. Original magnification: 400×.
Mentions: Next, we explored the effect of TSH on ATGL expression in the differentiated 3T3-L1 cells. Fully differentiated 3T3-L1 cells were treated in the absence or presence of bTSH for 24 h and 48 h. ATGL expression was determined by Western blotting and RT-PCR, respectively. As shown in Fig. 3A, and Fig. 3B, TSH inhibited ATGL protein expression and mRNA expression. The reductions of ATGL expression in the 3T3-L1 cells were approximately 30%, 60% and 60% following treatment with 0.1 μM, 1 μM and 2 μM TSH, respectively. These results confirmed that TSH directly decreased the expression of ATGL in the mature 3T3-L1 cells.

Bottom Line: The inhibitory effects of TSH on ATGL expression were abolished by H89, which is a protein kinase A (PKA) inhibitor.These results indicate that TSH has an inhibitory effect on ATGL expression in mature adipocytes.The associated mechanism is related to PKA activation.

View Article: PubMed Central - PubMed

Affiliation: Department of Endocrinology and Metabolism, Shandong Provincial Hospital affiliated to Shandong University, Jinan, Shandong, China; Department of Endocrinology and Metabolism, The Second Hospital of Shandong University, Jinan, Shandong, China.

ABSTRACT
Thyroid-stimulating hormone (TSH) has been shown to play an important role in the regulation of triglyceride (TG) metabolism in adipose tissue. Adipose triglyceride lipase (ATGL) is a rate-limiting enzyme controlling the hydrolysis of TG. Thus far, it is unclear whether TSH has a direct effect on the expression of ATGL. Because TSH function is mediated through the TSH receptor (TSHR), TSHR knockout mice (Tshr-/- mice) (supplemented with thyroxine) were used in this study to determine the effects of TSHR deletion on ATGL expression. These effects were verified in 3T3-L1 adipocytes and potential underlying mechanisms were explored. In the Tshr-/- mice, ATGL expression in epididymal adipose tissue was significantly increased compared with that in Tshr+/+ mice. ATGL expression was observed to increase with the differentiation process of 3T3-L1 preadipocytes. In mature 3T3-L1 adipocytes, TSH significantly suppressed ATGL expression at both the protein and mRNA levels in a dose-dependent manner. Forskolin, which is an activator of adenylate cyclase, suppressed the expression of ATGL in 3T3-L1 adipocytes. The inhibitory effects of TSH on ATGL expression were abolished by H89, which is a protein kinase A (PKA) inhibitor. These results indicate that TSH has an inhibitory effect on ATGL expression in mature adipocytes. The associated mechanism is related to PKA activation.

Show MeSH
Related in: MedlinePlus