Abstract The purpose of this study was to explore the effects of KYIPIQ, an angiotensin I-converting enzyme (ACE) inhibitory peptide found in yak milk casein, on the production of nitric oxide (NO) in human vascular endothelial cells (HUVECs). Additionally, we also sought to study the transport pathway of this peptide across monolayers of the human epithelial colorectal adenocarcinoma cell line (Caco-2). Treatment with peptide KYIPIQ increased NO synthesis and expression of phosphorylated endothelial nitric oxide synthase (eNOS) in HUVECs. Our results demonstrate that KYIPIQ-induced eNOS phosphorylation is dependent on the protein kinase B (Akt) activation pathway. Furthermore, our data indicate that the peptide KYIPIQ can be transported across the Caco-2 cell monolayer and that paracellular transport is the main transcellular mechanism. Thus, our studies suggest that KYIPIQ can be potentially used as a therapeutic agent for the treatment of hypertension.

中文翻译：

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来自牦牛乳酪蛋白的 ACE 抑制肽 KYIPIQ 诱导 HUVEC 中一氧化氮的产生，并通过 Caco-2 单层中的跨细胞机制扩散

摘要 本研究的目的是探讨KYIPIQ（一种在牦牛乳酪蛋白中发现的血管紧张素I 转换酶（ACE）抑制肽）对人血管内皮细胞（HUVECs）中一氧化氮（NO）产生的影响。此外，我们还试图研究该肽跨单层人上皮结肠直肠腺癌细胞系 (Caco-2) 的转运途径。用肽 KYIPIQ 处理增加了 HUVEC 中 NO 的合成和磷酸化内皮一氧化氮合酶 (eNOS) 的表达。我们的结果表明 KYIPIQ 诱导的 eNOS 磷酸化依赖于蛋白激酶 B (Akt) 激活途径。此外，我们的数据表明肽 KYIPIQ 可以跨 Caco-2 细胞单层运输，并且细胞旁运输是主要的跨细胞机制。因此，