核因子-κB (NF-κB) 信号通路调节特定的免疫反应并控制广泛的生理过程。NF-κB 抑制剂α (IKBA) 是细胞质中的 NF-κB 抑制介质,可调节 NF-κB 蛋白的核转位和 DNA 结合活性。然而,经典 NF-κB 信号通路的上游级联是否具有独立于 IKBA 介导的转录激活的生理作用仍不清楚。在此我们研究了 IKBA 在成熟精子中的功能,其中不发生转录和平移事件。IKBA 在人类精子中高度表达。其抑制剂 Bay117082 对 IKBA 磷酸化的抑制显着增强了精子活力。相反,脂多糖刺激的 IKBA 磷酸化显着降低了精子活力。尽管如此,Bay117082 处理并不影响 IKBA 敲除精子的活力。此外,非靶向代谢组学分析和药理学阻断试验表明,Bay117082 诱导的精子活力增加可归因于脂肪酸 β-氧化 (FAO) 增强。此外,我们发现 IKBA 磷酸化抑制导致 FAO 代谢途径中乙酰辅酶 A 羧化酶水平显着降低。我们的研究结果表明 IKBA 介导的信号协调精子运动程序并提高我们对细胞中转录非依赖性 NF-κB 信号通路的理解。非靶向代谢组学分析和药理学阻断试验表明,Bay117082 诱导的精子活力增加可归因于脂肪酸 β-氧化 (FAO) 增强。此外,我们发现 IKBA 磷酸化抑制导致 FAO 代谢途径中乙酰辅酶 A 羧化酶水平显着降低。我们的研究结果表明 IKBA 介导的信号协调精子运动程序并提高我们对细胞中转录非依赖性 NF-κB 信号通路的理解。非靶向代谢组学分析和药理学阻断试验表明,Bay117082 诱导的精子活力增加可归因于脂肪酸 β-氧化 (FAO) 增强。此外,我们发现 IKBA 磷酸化抑制导致 FAO 代谢途径中乙酰辅酶 A 羧化酶水平显着降低。我们的研究结果表明 IKBA 介导的信号协调精子运动程序并提高我们对细胞中转录非依赖性 NF-κB 信号通路的理解。
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IKBA phosphorylation governs human sperm motility through ACC-mediated fatty acid beta-oxidation
The nuclear factor-κB (NF-κB) signaling pathway regulates specific immunological responses and controls a wide range of physiological processes. NF-κB inhibitor alpha (IKBA) is an NF-κB inhibitory mediator in the cytoplasm that modulates the nuclear translocation and DNA binding activities of NF-κB proteins. However, whether the upstream cascade of the canonical NF-κB signaling pathway has physiological roles independent of IKBA-mediated transcriptional activation remains unclear. Herein we investigated the function of IKBA in mature sperm in which transcriptional and translational events do not occur. IKBA was highly expressed in human sperm. The repression of IKBA phosphorylation by its inhibitor Bay117082 markedly enhanced sperm motility. On the contrary, lipopolysaccharide-stimulated IKBA phosphorylation significantly decreased sperm motility. Nevertheless, Bay117082 treatment did not affect the motility of IKBA-knockout sperm. Further, untargeted metabolomic analysis and pharmacological blocking assays revealed that the Bay117082-induced increase in sperm motility was attributable to fatty acid β-oxidation (FAO) enhancement. In addition, we found that IKBA phosphorylation inhibition resulted in a significant reduction of acetyl-CoA carboxylase levels in the FAO metabolic pathway. Our findings indicate that IKBA-mediated signaling orchestrates sperm motility program and improves our understanding of transcription-independent NF-κB signaling pathway in cells.