PPARγ regulates fabp4 expression to increase DHA content in golden pompano (Trachinotus ovatus) hepatocytes
PPARγ regulates fabp4 expression to increase DHA content in golden pompano (Trachinotus ovatus) hepatocytes
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DOI：
10.1017/s0007114521000775
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发表时间：
2022-01-14
影响因子：
3.6
通讯作者：
Li, Yuanyou
中科院分区：
文献类型：
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作者：
Lei, Caixia;Fan, Bin;Li, Yuanyou
N-3 长链 (>= C20) PUFA (LC-PUFA) 是对鱼类和人类至关重要的脂肪酸。作为人类消费者 n-3 LC-PUFA 的主要来源，养殖鱼类的 n-3 LC-PUFA 含量非常重要。此前，我们确定脂肪酸结合蛋白（fabp）-4作为调节n-3 LC-PUFA含量的候选基因。在此，我们进一步评估了 fabp4 在此过程中的作用。首先，克隆了卵形鲳鲹fabp4的2059 bp启动子序列，并采用渐进删除的方法，确定-2006 bp至-1521 bp为核心启动子序列。 PPAR-γ 结合位点预计出现在该区域。荧光素酶报告基因检测显示，PPAR γ 结合位点突变后，fabp4 的启动子活性降低，并且 PPAR γ 以剂量依赖性方式增加 fabp4 启动子活性，这意味着 T. ovatus fabp4 是 PPAR γ 的靶标。 fabp4 或 PPAR γ 的过度表达增加了肝细胞中的 DHA 含量，而抑制其表达则减弱了这种作用，表明 fabp4 和 PPAR γ 在调节 DHA 含量方面发挥着积极作用。此外，抑制 fabp4 减弱了 PPAR γ 介导的 DHA 含量的增加，而 fabp4 的过度表达则减轻了这种影响。总的来说，我们的研究结果表明，由 PPAR gamma 控制的 fabp4 在 DHA 含量调节中发挥着重要作用。新的调控轴可以被认为是增加 T. ovatus 中 n-3 LC-PUFA 含量的有前途的新目标。
N-3 long-chain (>= C20) PUFA (LC-PUFA) are vital fatty acids for fish and humans. As a main source of n-3 LC-PUFA for human consumers, the n-3 LC-PUFA content of farmed fish is important. Previously, we identified fatty acid-binding protein (fabp)-4 as a candidate gene for regulating the n-3 LC-PUFA content. Herein, we further assessed the role of fabp4 in this process. First, a 2059 bp promoter sequence of fabp4 in Trachinotus ovatus was cloned and, using progressive deletion, determined -2006 bp to -1521 bp to be the core promoter sequence. The PPAR-gamma binding sites were predicted to occur in this region. A luciferase reporter assay showed that the promoter activity of fabp4 decreased following mutation of the PPAR gamma binding site and that PPAR gamma increased the fabp4 promoter activity in a dose-dependent manner, implying that T. ovatus fabp4 is a target of PPAR gamma. The overexpression of fabp4 or PPAR gamma increased the DHA content in hepatocytes, whereas suppression of their expression diminished this effect, suggesting that both fabp4 and PPAR gamma play an active role in regulating DHA content. Moreover, the inhibition of fabp4 attenuated the increase in PPAR gamma-mediated DHA content, and the overexpression of fabp4 alleviated this effect. Collectively, our findings indicated that fabp4, which is controlled by PPAR gamma, plays an important role in DHA content regulation. The new regulation axis can be considered a promising novel target for increasing the n-3 LC-PUFA content in T. ovatus.