LL-37诱导人鼻黏膜上皮细胞凋亡的潜在机制研究

目的 研究抗菌肽LL-37对人鼻黏膜上皮细胞凋亡的影响,并探讨其潜在的作用机制。 方法 体外培养人鼻黏膜上皮细胞,用不同浓度的LL-37处理细胞后,CCK-8法鼻黏膜上皮细胞增殖情况,流式细胞术检测细胞凋亡情况,Western blot检测细胞中凋亡相关蛋白活化的含半胱氨酸的天冬氨酸蛋白水解酶3(cleaved caspase-3)、活化的含半胱氨酸的天冬氨酸蛋白水解酶9(cleaved caspase-9)和Bax蛋白表达水平,ELISA法检测细胞培养上清中细胞炎症因子肿瘤坏死因子-α(TNF-α)、白细胞介素-6(IL-6)、白细胞介素-8(IL-8)的分泌量。 结果 与0 μg/ml组细胞比,添加LL-37能够抑制鼻黏膜上皮细胞增殖,且呈浓度依赖性,诱导鼻黏膜上皮细胞发生凋亡,上调鼻黏膜上皮细胞中cleaved caspase-3、cleaved caspase-9和Bax蛋白的表达,有效降低鼻黏膜上皮细胞中TNF-α、IL-6、IL-8的分泌,差异有统计学意义(P<0.05)。 结论 LL-37能够在体外抑制鼻黏膜上皮细胞增殖,诱导细胞凋亡,其可能的作用机制与上调cleaved caspase-3、cleaved caspase-9和Bax蛋白水平,促进细胞中TNF-α、IL-6、IL-8的分泌有关。

Potential mechanism of LL-37-induced apoptosis in human nasal epithelial cells

Objective To study the effect of antimicrobial peptide LL-37 on apoptosis of human nasal epithelial cells, and to explore its potential mechanism. Methods Human nasal mucosa epithelial cells were cultured in vitro. After treatment with different concentration of LL-37, the proliferation of nasal mucosa epithelial cells was detected by CCK-8 method, and the apoptosis of the cells by flow cytometry. Western blot was used to detect the expression levels of apoptosis-related proteins, including activated cysteine-containing aspartate proteolytic enzyme 3 (cleaved caspase-3), activated cysteine-containing aspartate proteolytic enzyme 9 (cleaved caspase-9) and Bax protein. ELISA was employed to detect the secretion of cytokines, including tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and interleukin-8 (IL-8). Results Compared with the 0 μg/ml group, LL-37 could inhibit the proliferation of nasal epithelial cells in a concentration-dependent manner, induce the apoptosis of nasal epithelial cells, up-regulate the expression levels of cleaved caspase-3, cleaved caspase-9 and Bax protein in nasal epithelial cells, and effectively reduce the secretion of TNF-α, IL-6 and IL-8 in nasal epithelial cells, and the differences were statistically significant (all P<0.05). Conclusions LL-37 can inhibit the proliferation of nasal epithelial cells in vitro and induce the apoptosis of the cells. The possible mechanism of action may be related to up-regulating cleaved caspase-3, cleaved caspase-9 and Bax protein expression levels and promoting the secretion of TNF-α, IL-6 and IL-8.