School of Animal Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA, United States of America.
School of Neuroscience, Virginia Polytechnic Institute and State University, Blacksburg, VA, United States of America.
PLoS One. 2023 Apr 10;18(4):e0284286. doi: 10.1371/journal.pone.0284286. eCollection 2023.
Obesity is a complex medical condition that is linked to various health complications such as infertility, stroke, and osteoarthritis. Understanding the neurobiology of obesity is crucial for responding to the etiology of this disease. The hypothalamus coordinates many integral activities such as hormone regulation and feed intake and numerous studies have observed altered hypothalamic gene regulation in obesity models. Previously, it was reported that the promoter region of the satiety gene, Pomc, has increased DNA methylation in the hypothalamus following short-term exposure to a high fat diet, suggesting that epigenetic-mediated repression of hypothalamic Pomc might contribute to the development of obesity. However, due to technical limitations, this has never been directly tested. Here, we used the CRISPR-dCas9-TET1 and dCas9-DNMT3a systems to test the role of Pomc DNA methylation in the hypothalamus in abnormal weight gain following acute exposure to a high fat diet in male rats. We found that exposure to a high fat diet increases Pomc DNA methylation and reduces gene expression in the hypothalamus. Despite this, we found that CRISPR-dCas9-TET1-mediated demethylation of Pomc was not sufficient to prevent abnormal weight gain following exposure to a high fat diet. Furthermore, CRISPR-dCas9-DNMT3a-mediated methylation of Pomc did not alter weight gain following exposure to standard or high fat diets. Collectively, these results suggest that high fat diet induced changes in Pomc DNA methylation are a consequence of, but do not directly contribute to, abnormal weight gain during the development of obesity.
肥胖是一种复杂的医学病症，与多种健康并发症有关，如不孕、中风和骨关节炎。了解肥胖的神经生物学对于应对这种疾病的病因至关重要。下丘脑协调着许多重要的活动，如激素调节和摄食，许多研究已经观察到肥胖模型中下丘脑基因调节的改变。此前有报道称，饱腹基因 Pomc 的启动子区域在短期暴露于高脂肪饮食后，其在下丘脑的 DNA 甲基化增加，这表明表观遗传介导的下丘脑 Pomc 抑制可能导致肥胖的发生。然而，由于技术限制，这从未被直接测试过。在这里，我们使用 CRISPR-dCas9-TET1 和 dCas9-DNMT3a 系统来测试 Pomc DNA 甲基化在雄性大鼠急性暴露于高脂肪饮食后引起的下丘脑异常体重增加中的作用。我们发现，暴露于高脂肪饮食会增加 Pomc 的 DNA 甲基化并降低其在下丘脑的表达。尽管如此，我们发现 CRISPR-dCas9-TET1 介导的 Pomc 去甲基化不足以防止高脂肪饮食暴露后的异常体重增加。此外，CRISPR-dCas9-DNMT3a 介导的 Pomc 甲基化并没有改变标准或高脂肪饮食暴露后的体重增加。总的来说，这些结果表明，高脂肪饮食诱导的 Pomc DNA 甲基化变化是肥胖发展过程中异常体重增加的结果，但不是直接原因。
