A stimulatory TSH receptor antibody enhances adipogenesis via phosphoinositide 3-kinase activation in orbital preadipocytes from patients with Graves' ophthalmopathy.
A stimulatory TSH receptor antibody enhances adipogenesis via phosphoinositide 3-kinase activation in orbital preadipocytes from patients with Graves' ophthalmopathy.
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DOI：
10.1530/jme-11-0006
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发表时间：
2011-06
影响因子：
3.5
通讯作者：
Bahn RS
中科院分区：
文献类型：
--
作者：
Kumar S;Nadeem S;Stan MN;Coenen M;Bahn RS
Graves眼病(GO)的特征是眼眶组织体积扩大，伴随着血清TSH受体(TSHR)自身抗体水平的升高。由于之前的研究已经证明了GO眼眶内脂肪生成的证据，我们试图确定M22，一种针对TSHR的人类单抗是否促进GO患者眼眶成纤维细胞的脂肪生成，如果是，则确定相关的信号机制。10只GO眼眶成纤维细胞在无血清脂肪细胞分化培养液中分别加入牛促甲状腺激素(1或10·0 U/L)或M22(1或10 ng/ml)处理10天。一些培养物还接受了磷脂酰肌醇3-激酶(PI3K)抑制剂或cAMP产生的抑制剂。在其他实验中，融合培养物(n=8)用促甲状腺激素(0.1-10·0 U/L)或M22(0.1-100 ng/ml)处理1-30 分钟，测定cAMP产生或磷酸化AKT(PACT)水平。我们发现，经M22(2.6倍±0.7；P=0.03)或TSH(13.2±5.8倍，P=0.048)处理10天的GO细胞，脂联素、瘦素和TSHR的mRNA水平均升高。在其他研究中，M22和TSH刺激GO细胞中cAMP的产生和PACT水平。抑制PI3K活性可降低M22刺激的脂联素基因表达水平(67±12%；P=0.021)以及脂联素和CCAAT/增强子结合蛋白α蛋白水平。综上所述，M22是GO眼眶前脂肪细胞的促成脂因子。这种抗体似乎通过PI3K信号级联起作用，提示抑制PI3K信号可能是GO一种潜在的新治疗方法。
Graves' ophthalmopathy (GO) is characterized by expanded volume of the orbital tissues associated with elevated serum levels of TSH receptor (TSHR) autoantibodies. Because previous studies have demonstrated evidence of adipogenesis within the GO orbit, we sought to determine whether M22, a human monoclonal antibody directed against TSHR, enhances adipogenesis in orbital fibroblasts from patients with GO and, if so, to identify signaling mechanisms involved. GO orbital fibroblast cultures (n=10) were treated for 10 days with bovine TSH (1 or 10·0 U/l) or M22 (1 or 10 ng/ml) in serum-free adipocyte differentiation medium. Some cultures also received a phosphoinositide 3-kinase (PI3K) inhibitor or an inhibitor of cAMP production. In other experiments, confluent cultures (n=8) were treated for between 1 and 30 min with TSH (0·1–10·0 U/l) or M22 (0·1–100 ng/ml) with measurement of cAMP production or levels of phosphorylated AKT (pAKT). We found levels of adiponectin, leptin, and TSHR mRNA to be increased in GO cultures treated for 10 days with either M22 (2·6 mean fold ±0·7; P=0·03) or TSH (13·2±5·8-fold, P=0·048). In other studies, M22 and TSH stimulated cAMP production and pAKT levels in GO cells. Inhibition of PI3K activity during 10 days in culture decreased the levels of M22-stimulated mRNA encoding adiponectin (67±12%; P=0·021), as well as adiponectin and CCAAT/enhancer-binding protein α protein levels. In conclusion, M22 is a pro-adipogenic factor in GO orbital preadipocytes. This antibody appears to act via the PI3K signaling cascade, suggesting that inhibition of PI3K signaling may represent a potential novel therapeutic approach in GO.