PDGF-induced Hepatic Stellate Cells Research Articles

IL-8 exacerbates CCl4-induced liver fibrosis in human IL-8-expressing mice via the PI3K/Akt/HIF-1α pathway

Liver fibrosis is an excessive accumulation of extracellular matrix (ECM) due to chronic liver injury. In recent years, the mechanism of liver fibrosis has been extensively studied. Hepatic stellate cells (HSCs) play an important role in the occurrence and development of liver fibrosis because activated hepatic stellate cells could synthesize a large number of ECM and thus participate in the process of liver fibrosis. Interleukin-8 (IL-8) (deletion in mice) is a versatile chemokine that promotes inflammation and affects cell growth by activating related pathways and plays an important role in the development and progression of a variety of diseases. Notably, the expression level of IL-8 was significantly higher in patients with liver fibrosis, suggesting that it may be related to the pathogenesis of liver fibrosis. In this study, we used hydrodynamic injection to deliver the lentiviral vector LV5-hIL-8 into mice. We found that hIL-8 could aggravate carbon tetrachloride (CCl4)-induced liver fibrosis through the PI3K/Akt/HIF-1α pathway. It is characterized by excessive accumulation of ECM as well as a significant increase in markers of liver injury. In addition, in PDGF-induced HSCs, we also demonstrated that hIL-8 could aggravate ECM accumulation through the PI3K/Akt/HIF-1α pathway. In conclusion, the results of this study on hIL-8 may help to identify potential targets for the clinical treatment of liver fibrosis.

PI3-kinase/Akt pathway-regulated membrane transportation of acid-sensing ion channel 1a/Calcium ion influx/endoplasmic reticulum stress activation on PDGF-induced HSC Activation.

Acid‐sensing ion channel 1a (ASIC1a) allows Na+ and Ca2+ flow into cells. It is expressed during inflammation, in tumour and ischaemic tissue, in the central nervous system and non‐neuronal injury environments. Endoplasmic reticulum stress (ERS) is caused by the accumulation of misfolded proteins that interferes with intracellular calcium homoeostasis. Our recent reports showed ASIC1a and ERS are involved in liver fibrosis progression, particularly in hepatic stellate cell (HSC) activation. In this study, we investigated the roles of ASIC1a and ERS in activated HSC. We found that ASIC1a and ERS‐related proteins were up‐regulated in carbon tetrachloride (CCl4)‐induced fibrotic mouse liver tissues, and in patient liver tissues with hepatocellular carcinoma with severe liver fibrosis. The results show silencing ASIC1a reduced the expression of ERS‐related biomarkers GRP78, Caspase12 and IREI‐XBP1. And, ERS inhibition by 4‐PBA down‐regulated the high expression of ASIC1a induced by PDGF, suggesting an interactive relationship. In PDGF‐induced HSCs, ASIC1a was activated and migrated to the cell membrane, leading to extracellular calcium influx and ERS, which was mediated by PI3K/AKT pathway. Our work shows PDGF‐activated ASIC1a via the PI3K/AKT pathway, induced ERS and promoted liver fibrosis progression.