Department of Surgery, University of Texas Medical Branch, Galveston, TX 77555, USA.
School of Medicine, Alabama College of Osteopathic Medicine, Dothan, AL 36303, USA.
Int J Mol Sci. 2018 May 24;19(6):1567. doi: 10.3390/ijms19061567.
Hepatic stellate cell (HSC) activation is responsible for hepatic fibrogenesis and is associated with an overexpression of transcription 3 (STAT3). Luteolin, a common dietary flavonoid with potent anti-inflammatory properties, has previously demonstrated antifibrogenic properties in HSCs but the mechanism has not been fully elucidated. Activated human and rat hepatic stellate cell lines LX-2 and HSC-T6 were used to study the effects of luteolin on HSCs. Cellular proteins were determined by western blot and immunofluorescence. Cell proliferation was assessed with Alamar Blue assay. Luteolin significantly decreased LX-2 and HSC-T6 cell viability in a time-and-dose-dependent manner, as well as decreased HSC end-products α-smooth muscle actin (α-SMA), collagen I, and fibronectin. Luteolin decreased levels of total and phosphorylated STAT3, suppressed STAT3 nuclear translocation and transcriptional activity, and attenuated expression of STAT3-regulated proteins c-myc and cyclin D1. STAT3 specific inhibitors stattic and SH-4-54 demonstrated similar effects on HSC viability and α-SMA production. In LX-2 and HSC-T6 cells, luteolin demonstrates a potent ability to inhibit hepatic fibrogenesis via suppression of the STAT3 pathway. These results further elucidate the mechanism of luteolin as well as the effect of the STAT3 pathway on HSC activation.
肝星状细胞 (HSC) 的激活负责肝纤维化的发生，并与转录因子 3 (STAT3) 的过度表达有关。木樨草素是一种常见的具有强大抗炎特性的膳食类黄酮，先前已证明其在 HSCs 中具有抗纤维化特性，但机制尚未完全阐明。我们使用激活的人源和大鼠肝星状细胞系 LX-2 和 HSC-T6 来研究木樨草素对 HSCs 的影响。通过 Western blot 和免疫荧光法测定细胞蛋白。通过 Alamar Blue 测定法评估细胞增殖。木樨草素呈时间和剂量依赖性地显著降低 LX-2 和 HSC-T6 细胞活力，并降低 HSC 终产物α-平滑肌肌动蛋白 (α-SMA)、I 型胶原和纤维连接蛋白。木樨草素降低总 STAT3 和磷酸化 STAT3 的水平，抑制 STAT3 核易位和转录活性，并减弱 STAT3 调节的蛋白 c-myc 和细胞周期蛋白 D1 的表达。STAT3 特异性抑制剂 stattic 和 SH-4-54 对 HSC 活力和α-SMA 产生也具有类似的作用。在 LX-2 和 HSC-T6 细胞中，木樨草素通过抑制 STAT3 通路显示出强大的抑制肝纤维化的能力。这些结果进一步阐明了木樨草素的作用机制以及 STAT3 通路对 HSC 激活的影响。
