Objective

Obesity is recognized as the cause of multiple metabolic diseases and is rapidly increasing worldwide. As obesity is due to an imbalance in energy homeostasis, the promotion of energy consumption through browning of white adipose tissue (WAT) has emerged as a promising therapeutic strategy to counter the obesity epidemic. However, the molecular mechanisms of the browning process are not well understood. In this study, we investigated the effects of the GATA family of transcription factors on the browning process.

Methods

We used qPCR to analyze the expression of GATA family members during WAT browning. In order to investigate the function of GATA3 in the browning process, we used the lentivirus system for the ectopic expression and knockdown of GATA3. Western blot and real-time qPCR analyses revealed the regulation of thermogenic genes upon ectopic expression and knockdown of GATA3. Luciferase reporter assays, co-immunoprecipitation, and chromatin immunoprecipitation were performed to demonstrate that GATA3 interacts with proliferator-activated receptor-γ co-activator-1α (PGC-1α) to regulate the promoter activity of uncoupling protein-1 (UCP-1). Enhanced energy expenditure by GATA3 was confirmed using oxygen consumption assays, and the mitochondrial content was assessed using MitoTracker. Furthermore, we examined the in vivo effects of lentiviral GATA3 overexpression and knockdown in inguinal adipose tissue of mice.

Results

Gata3 expression levels were significantly elevated in the inguinal adipose tissue of mice exposed to cold conditions. Ectopic expression of GATA3 enhanced the expression of UCP-1 and thermogenic genes upon treatment with norepinephrine whereas GATA3 knockdown had the opposite effect. Luciferase reporter assays using the UCP-1 promoter region showed that UCP-1 expression was increased in a dose-dependent manner by GATA3 regardless of norepinephrine treatment. GATA3 was found to directly bind to the promoter region of UCP-1. Furthermore, our results indicated that GATA3 interacts with the transcriptional coactivator PGC-1α to increase the expression of UCP-1. Taken together, we demonstrate that GATA3 has an important role in enhancing energy expenditure by increasing the expression of thermogenic genes both in vitro and in vivo.

Conclusion

GATA3 may represent a promising target for the prevention and treatment of obesity by regulating thermogenic capacity.

中文翻译：

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GATA3通过在脂肪组织褐变过程中直接与PGC-1α结合来诱导UCP-1的上调。

目的

肥胖被认为是引起多种代谢疾病的原因，并且在全世界范围内正在迅速增加。由于肥胖是由于能量稳态失衡引起的，通过白色脂肪组织褐变（WAT）促进能量消耗已成为对抗肥胖流行的一种有前途的治疗策略。但是，褐变过程的分子机理尚不十分清楚。在这项研究中，我们调查了GATA转录因子家族对褐变过程的影响。

方法

我们使用qPCR分析WAT褐变期间GATA家族成员的表达。为了研究GATA3在褐变过程中的功能，我们使用慢病毒系统对GATA3进行异位表达和敲除。Western印迹和实时qPCR分析揭示异位表达和GATA3敲除后产热基因的调节。进行了荧光素酶报告基因分析，免疫共沉淀和染色质免疫沉淀实验，以证明GATA3与增殖物激活受体-γ共激活物1α（PGC-1α）相互作用，调节解偶联蛋白1（UCP-1）的启动子活性。 。使用耗氧量测定法确认了GATA3增强的能量消耗，并使用MitoTracker评估了线粒体含量。此外，我们检查了体内 GATA3慢病毒在小鼠腹股沟脂肪组织中的过表达和抑制作用

结果

暴露于寒冷条件下的小鼠腹股沟脂肪组织中Gata3表达水平显着升高。用去甲肾上腺素处理后，异位表达的GATA3增强了UCP-1和致热基因的表达，而GATA3的抑制作用则相反。使用UCP-1启动子区域的萤光素酶报告基因分析表明，无论去甲肾上腺素治疗如何，GATA3均可使UCP-1表达以剂量依赖性方式增加。发现GATA3直接结合UCP-1的启动子区域。此外，我们的结果表明，GATA3与转录共激活因子PGC-1α相互作用以增加UCP-1的表达。综上所述，我们证明了GATA3在增加体外热原性基因的表达方面，在增加能量消耗方面具有重要作用。和体内。

结论

通过调节生热能力，GATA3可能代表了预防和治疗肥胖的有希望的目标。