Yu Minyi, He Wenyuan, Belsham Denise D
Departments of Physiology, University of Toronto, Ontario, Canada.
Departments of Physiology, University of Toronto, Ontario, Canada; Departments of Medicine, University of Toronto, Ontario, Canada.
Gene. 2025 Feb 10;937:149129. doi: 10.1016/j.gene.2024.149129. Epub 2024 Nov 29.
Obesity is a complex disease marked by increased adiposity and impaired metabolic function. While diet and lifestyle are primary causes, endocrine-disrupting chemicals (EDCs), such as bisphenol A (BPA), significantly contribute to obesity. BPA, found in plastic consumer products, accumulates in the hypothalamus and dysregulates energy homeostasis by disrupting the neuropeptide Y (NPY)/agouti-related peptide (AgRP) and pro-opiomelanocortin (POMC) neurons. However, the precise molecular mechanisms of how BPA disrupts neuropeptide expression remains unclear. We hypothesized that microRNAs (miRNAs), which regulate approximately 60% of the human protein-coding genome and are crucial for hypothalamic energy regulation, may mediate the effects of BPA on Agrp. Using the TargetScanMouse 8.0 and DIANA microT bioinformatics tools, we identified miR-501-5p as a potential miRNA that directly regulates Agrp and the miR-34 family as miRNAs that indirectly regulate Agrp through its transcription factor krüppel-like factor 4 (KLF4). We found that in an immortalized NPY/AgRP-expressing cell line, mHypoE-41, miR-501-5p unexpectedly upregulated Agrp, while miR-34a-5p reduced Klf4 and Agrp mRNA levels. Serum starvation reduced miR-34a-5p levels and elevated Agrp mRNA levels, suggesting a potential role in AgRP regulation. Inhibiting the miR-34a-5p interaction with the Klf4 3'UTR using a specific target site blocker prevented the downregulation of both Klf4 and Agrp, suggesting miR-34a-5p alters Agrp mRNA levels via regulation of KLF4. BPA treatment increased Agrp and Klf4 expression while simultaneously decreasing miR-34a-5p levels, indicating miR-34a-5p may play a role in BPA-mediated dysregulation of Agrp. Overall, this study highlights indirect miRNA-based regulation of Agrp, which can also be dysregulated by obesogens, such as BPA.
肥胖是一种复杂的疾病，其特征是肥胖增加和代谢功能受损。虽然饮食和生活方式是主要原因，但内分泌干扰化学物质（EDC），如双酚A（BPA），对肥胖有显著影响。BPA存在于塑料消费品中，会在下丘脑中积累，并通过干扰神经肽Y（NPY）/刺鼠相关肽（AgRP）和阿黑皮素原（POMC）神经元来破坏能量稳态。然而，BPA如何破坏神经肽表达的精确分子机制仍不清楚。我们推测，微小RNA（miRNA）可能介导BPA对Agrp的影响，miRNA可调控约60%的人类蛋白质编码基因组，对下丘脑能量调节至关重要。使用TargetScanMouse 8.0和DIANA microT生物信息学工具，我们确定miR-501-5p是直接调控Agrp的潜在miRNA，而miR-34家族是通过其转录因子Krüppel样因子4（KLF4）间接调控Agrp的miRNA。我们发现，在永生化的表达NPY/AgRP的细胞系mHypoE-41中，miR-501-5p意外地上调了Agrp，而miR-34a-5p降低了Klf4和Agrp mRNA水平。血清饥饿降低了miR-34a-5p水平并升高了Agrp mRNA水平，表明其在AgRP调节中可能发挥作用。使用特异性靶位点阻断剂抑制miR-34a-5p与Klf4 3'UTR的相互作用可防止Klf4和Agrp的下调，表明miR-34a-5p通过调控KLF4改变Agrp mRNA水平。BPA处理增加了Agrp和Klf4的表达，同时降低了miR-34a-5p水平，表明miR-34a-5p可能在BPA介导的Agrp失调中起作用。总体而言，本研究强调了基于miRNA的对Agrp的间接调控，这种调控也可能被肥胖诱导物（如BPA）破坏。
