TWEAK increases SIRT1 expression and promotes p53 deacetylation affecting human hepatic stellate cell senescence

Abstract

To detect the effects of tumor necrosis factor-like weak inducer of apoptosis (TWEAK) on SIRT1 expression and p53 deacetylation, involving cell senescence, in activated human hepatic stellate cell (HSC) in vitro, human HSC LX-2 was cultured with TWEAK for 24 h. The result showed that the expression of membrane receptor Fn14 was remarkably increased by TWEAK, which upregulated SIRT1 in LX-2 cells, detected by Western blotting and real-time PCR. The expression of p53 was not significantly altered; however, the ac-p53 was decreased. Furthermore, the viability of LX-2 cells was significantly enhanced by TWEAK. The activity of SA-β-Gal was notably inhibited, showing a suppressing effect of TWEAK on the senescence of activated HSC. Primary cultured HSC on days 7 and 11 was used to examine the expression of TWEAK, Fn14, SIRT1, and the activity of SA-β-Gal. The result indicated that the mRNA of TWEAK, SIRT1, and Fn14 was all decreased on day 11 compared to that on day 7, and the activity of SA-β-Gal was higher on day 11 than that on day 7. The present study suggested that TWEAK enhanced the expression of SIRT1 and decreased the acetylation of p53, probably inhibiting the senescence of activated HSC in vitro, which provides a molecular basis for TWEAK as a potential target in the therapy of liver fibrosis.

TWEAK/Fn14 promotes oxidative stress through AMPK/PGC‑1α/MnSOD signaling pathway in endothelial cells

“…Cells were incubated at 37˚C in a humidified atmosphere of 5% CO 2 and 95% air and grown to 70 to 80% confluence. For the experiments, the HUVECs were treated with 50, 100 and 200 ng/ml TWEAK respectively based on previous studies (15)(16)(17). As for Fn14 siRNA, for each well of a 6-well plate, cells were transfected with 5 µl siRNA (20 µM) or negative control (Ncontrol group) using Lipofectamine 2000 (Invitrogen, Carlsbad, CA, USA) for 48 h. To confirm that AMPK activation is required for the expression of PGC-1α and MnSOD, HUVECs were treated by 10 µmol/l GSK621 as previous described (18,19).…”

Hepatic stellate cells as key target in liver fibrosis

“…TWEAK also leads to liver fibrosis progression by directly promoting HSC proliferation. TWEAK, and by enhancing SIRT1 expression and decreasing p53 acetylation, which assumedly inhibits HSC senescence [199, 200]. …”

Epigenetics in Liver Fibrosis: Could HDACs be a Therapeutic Target?

“…Moreover, AMPK activation has also been shown to attenuate liver injury and fibrosis in BDL rats through non-canonical NF-κB pathway inhibition and subsequent downregulation of inflammatory cytokines such as Tnf-α , Il-β , Il-21 , and Ccl21 [ 104 ]. However, a recent study suggested that TWEAK-induced SIRT1 upregulation inhibits LX2 cells senescence in parallel with α-SMA increased expression [ 105 ]. Therefore, more studies are required to fully understand the potential roles of SIRT1 in the hepatic fibrogenesis.…”