injection. p16, p21 and Hmga1 in cell model. Importantly, our study identified the transcription factor GATA6 as an upstream molecule in the facilitation of DHA-induced HSC senescence. GATA6 accumulation promoted DHA-induced p53 and p16 upregulation, and contributed to HSC senescence. By contrast, siRNA-mediated knockdown of GATA6 dramatically abolished DHA-induced upregulation of p53 and p16, and Hpse in turn inhibited HSC senescence. Interestingly, DHA also appeared to increase autophagosome generation and autophagic flux in activated HSCs, which was underlying mechanism for DHA-induced GATA6 accumulation. Autophagy depletion impaired GATA6 accumulation, while autophagy induction showed a synergistic effect with DHA. Attractively, p62 was found to act as Amrubicin a negative regulator of GATA6 accumulation. Treatment of cultured HSCs with various autophagy inhibitors, led to an inhibition of DHA-induced p62 degradation, and in turn, prevented DHA-induced GATA6 accumulation and HSC senescence. Overall, these results provide novel implications to reveal the molecular mechanism of DHA-induced senescence, by which points to the possibility of using DHA based proautophagic drugs for the treatment of liver fibrosis. Liver fibrosis is a reversible wound-healing response following liver injury, and its end-stage cirrhosis is responsible for high morbidity and mortality worldwide.1, 2, 3 Liver transplantation is the only treatment Amrubicin available for patients with advanced stages of liver fibrosis.4, 5, 6 Therefore, new therapeutic agents and strategies are needed for the management of this disease.7, 8 Dihydroartemisinin (DHA), a natural and safe anti-malarial agent, exhibits an ample array of pharmacological activities such as anti-tumor,9 anti-bacterial10 and anti-schistosomiasis properties.11 Amrubicin We previously reported that DHA treatment improved the inflammatory microenvironment of liver fibrosis control, **control, ***control DHA promotes activated HSC senescence by plating freshly isolated HSCs exposed to platelet derived growth factor-BB (PDGF-BB) on plastic tissue culture dishes.12, 13, 14, 15, 16, 26 Therefore, the freshly quiescent HSCs were isolated from Sprague-Dawley rats as described, 27 and then were treated with 5, 10 and 20?ng/ml PDGF-BB. In agreement with previous findings,12, 13, 14, 15, 16 HSC activation markers like were significantly upregulated showing that HSCs undergo an activation process as well (Supplementary Figures 2ACC). Subsequently, we used cultured HSCs to test whether DHA treatment could promote activated HSC senescence control, **control, ***control Additional experiments were performed to verify the role of telomerase activity in DHA-induced HSC senescence. We found that the telomerase activity was decreased in DHA-treated HSCs (Supplementary Figure 2D). A well-known feature of cellular senescence is cell cycle arrest, which largely accounts for the growth inhibition in senescent cells.20 Next, we examined the cell cycle distribution by a flow cytometer. As shown in Supplementary Figures 2E and F, HSCs treated with DHA or Etoposide showed significantly higher proportions of G2/M cells and lower proportions of S cells compared with untreated HSCs. Cell cycle is influenced by multiple cyclins and cyclin-dependent kinases (CDKs).29 Real-time PCR analyses indicated that DHA treatment downregulated the expression of cyclin D1, cyclin E1 and CDK4 in activated HSCs (Supplementary Figure 2G). Taken together, these results show that DHA promotes activated HSC senescence control, **control, ***control. #DHA treatment, ##DHA treatment, ###DHA treatment DHA induces HSC senescence via a GATA6-dependent mechanism Fc fragment) and CCl4-treated group; group 4, DHA (20?mg/kg) and CCl4-treated group; group 5, Ad.Fc, DHA and CCl4-treated group; group 6, Ad.shGATA6 (adenovirus encoding mouse GATA6 shRNA for inhibiting GATA6 expression) and CCl4-treated group; group 7, Ad.shGATA6, DHA and CCl4-treated group. (a) The pathological changes of the liver were observed by Gross examination, Scale bars are 1cm. Liver sections were stained with hematoxylin and eosin, Masson reagents and Sirius red. Representative photographs are shown. (b,c,e) Primary HSCs were isolated and subsequently were used to determine the expression of GATA6, p53, p21 and p16. (d).