Comparative proteomics analysis indicates that palmatine contributes to transepithelial migration by regulating cellular adhesion

Palmatine, a biologically active isoquinoline alkaloid, possesses multiple pharmaceutical activities against mucosal infection and inflammation.
There are no reports about the influence of palmatine on uterine mucosal epithelial cells.
We used proteomics to analyse differentially expressed proteins (DEPs) in goat endometrial epithelial cells (EECs) stimulated by lipopolysaccharide (LPS, 5 μg/mL, the dosage can induce inflammatory response, according to our previous study) for 12 h and then treated with palmatine (80 μg/mL) for 8 h; the dosage was selected based on MTT assay. The EECs without any treatment were used as controls. Every group was treated in triplicate.
A total of 428 DEPs in LPS-stimulated group and 486 DEPs in the palmatine-treated group were identified. Functional annotation analysis showed that palmatine mainly regulated the protein expression of structural molecules involved in the response to stimuli. Pathway analysis showed that cell adhesion molecule (CaM) pathways were most significant enriched due to palmatine treatment. Junction adhesion molecule 1 (JAM1), nectin 1 (NECT1) and cadherin 5 (CDH5), which play important roles in the transepithelial migration (TEpM) of leukocytes, were significantly downregulated by palmatine. Meanwhile, other proteins essential to the maintenance of cell adhesion and those that facilitate leukocyte migration were upregulated after palmatine treatment.
Discussion and conclusions: The results suggested that palmatine regulates the expression of CaMs to affect TEpM during uterine mucosal inflammation and provides novel insight to understanding and developing palmatine pharmacology. Palmatine is a promising drug for treatment of mucosal inflammation.

巴马汀（Palmatine）是一种具有生物活性的异喹啉生物碱，对黏膜感染及炎症具有多种药理活性。
目前尚无关于巴马汀对子宫黏膜上皮细胞影响的相关研究报道。
本研究采用蛋白质组学技术，分析经脂多糖（LPS，5μg/mL，该剂量可诱导炎症反应，依据本团队前期研究）刺激12小时、随后以巴马汀（80μg/mL）干预8小时的山羊子宫内膜上皮细胞（EECs）中的差异表达蛋白（DEPs）；上述干预剂量均通过MTT实验筛选确定。以未接受任何处理的EECs作为空白对照组，每组实验均设置3次生物学重复。
研究共鉴定得到LPS刺激组中的428个DEPs，以及巴马汀干预组中的486个DEPs。功能注释分析结果显示，巴马汀主要调控参与应激应答的结构分子的蛋白表达水平。通路富集分析表明，经巴马汀干预后，细胞黏附分子（CaM）通路的富集程度最为显著。在白细胞跨上皮迁移（TEpM）过程中发挥关键作用的连接黏附分子1（JAM1）、连接素1（NECT1）以及钙黏蛋白5（CDH5）的表达均被巴马汀显著下调；与此同时，其他维持细胞黏附所必需的蛋白以及促进白细胞迁移的蛋白，在巴马汀干预后均呈现表达上调。
讨论与结论：本研究结果表明，在子宫黏膜炎症过程中，巴马汀可通过调控细胞黏附分子的表达来影响白细胞跨上皮迁移，为解析巴马汀的药理作用机制与新药开发提供了全新视角。巴马汀是一种极具应用前景的黏膜炎症治疗药物。