Department of Biomedicine & Health Sciences, The Catholic University Liver Research Centre, POSTECH-Catholic Biomedical Engineering Institute, The Catholic University of Korea, Seoul, Republic of Korea.
Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.
PLoS One. 2021 Dec 8;16(12):e0261067. doi: 10.1371/journal.pone.0261067. eCollection 2021.
Antifibrotic agent for the treatment of liver fibrosis has not been developed so far. Long term treatment of chronic hepatitis B patients with antiviral drugs tenofovir disoproxil fumarate (TDF) and entecavir (ETV) results in the regression of liver fibrosis, but the underlying mechanism has not been clarified. Therefore, we aimed to investigate the direct impact of TDF and ETV on liver fibrosis.
Activated hepatic stellate cell (HSC) cell lines were used to evaluate the effects of TDF and ETV. After treatment with each antiviral agent, cell viability, morphology, apoptotic features, autophagy and antifibrosis signalling pathways were examined. Then, collagen deposition, fibrosis markers and activated HSCs were measured in liver tissues of the liver fibrosis model mice.
After TDF treatment, the viabilities of LX2 and HSC-T6 cells were decreased, and the cells exhibited apoptotic features, but ETV did not induce these effects. Cleavage of PARP and Caspase-3 and the inhibition of the antiapoptotic gene Bcl-xl indicated activated HSC apoptosis following TDF treatment. TDF simultaneously increased autophagy, which also regulated apoptosis through crosstalk. TDF inactivated the PI3K/Akt/mTOR signalling pathway, which was associated with the activation of both apoptosis and autophagy. In the liver fibrosis mouse model, the fibrotic area and activated HSC markers were decreased by TDF but not ETV treatment. Additionally, apoptotic cells were concentrated in the periportal fibrotic area after TDF treatment, which indicated the specific antifibrotic effect of TDF.
TDF directly ameliorates liver fibrosis by downregulating the PI3K/Akt/mTOR signalling pathway, which results in the apoptosis of activated HSCs. The antifibrotic effects of TDF indicate that it may be a therapeutic agent for the treatment of liver fibrosis.
目前尚未开发出用于治疗肝纤维化的抗纤维化药物。长期使用抗病毒药物替诺福韦酯（TDF）和恩替卡韦（ETV）治疗慢性乙型肝炎患者可导致肝纤维化消退，但具体机制尚不清楚。因此，我们旨在研究 TDF 和 ETV 对肝纤维化的直接影响。
使用活化的肝星状细胞（HSC）细胞系来评估 TDF 和 ETV 的作用。用每种抗病毒药物处理后，检测细胞活力、形态、凋亡特征、自噬和抗纤维化信号通路。然后，在肝纤维化模型小鼠的肝组织中测量胶原沉积、纤维化标志物和活化的 HSCs。
TDF 处理后，LX2 和 HSC-T6 细胞活力降低，细胞出现凋亡特征，但 ETV 未诱导这些作用。PARP 和 Caspase-3 的切割以及抗凋亡基因 Bcl-xl 的抑制表明 TDF 处理后活化的 HSC 发生凋亡。TDF 同时增加自噬，自噬通过细胞间通讯也调节凋亡。TDF 使 PI3K/Akt/mTOR 信号通路失活，这与凋亡和自噬的激活有关。在肝纤维化小鼠模型中，TDF 而非 ETV 治疗可减少纤维化面积和活化的 HSC 标志物。此外，TDF 治疗后凋亡细胞集中在门脉周围纤维化区域，表明 TDF 具有特异性的抗纤维化作用。
TDF 通过下调 PI3K/Akt/mTOR 信号通路直接改善肝纤维化，导致活化的 HSCs 凋亡。TDF 的抗纤维化作用表明它可能是治疗肝纤维化的治疗药物。
