Journal
PLOS ONE
Volume 9, Issue 4, Pages -Publisher
PUBLIC LIBRARY SCIENCE
DOI: 10.1371/journal.pone.0095443
Keywords
-
Categories
Funding
- Tri-Service General Hospital [TSGH-C101-083, TSGH-C101-084]
- National Science Council, Taiwan [NSC 101-2314-B-195-006-MY3]
- Mackay Memorial Hospital [MMH-E-101-006]
Ask authors/readers for more resources
Pigment epithelium-derived factor (PEDF) has been shown previously to prevent liver fibrosis and hepatic stellate cell (HSC) activation. By investigating the functional domains in PEDF, we identified a 34-mer peptide (residues Asp44-Asn77) that harbors the same function as the full-length PEDF protein. Not only did the 34-mer suppress the development of fibrosis in carbon tetrachloride (CCl4)-treated mouse liver but it also upregulated peroxisome proliferator-activated receptor-gamma (PPAR gamma) expression in HSCs in vivo. Platelet-derived growth factor (PDGF) plays a crucial role on the process of HSC activation in response to liver damage. The 34-mer suppressed PDGF-induced cell proliferation and expression of myofibroblastic marker proteins in primary rat HSC culture, increased the levels of PPAR gamma mRNA and protein in a dose-dependent manner and markedly reduced the level of active beta-catenin protein, an HSC activating factor, in HSC-T6 cells. Similarly, IWR-1, an inhibitor of the Wnt response, displayed the same effect as the 34-mer in preventing HSC-T6 activation. The Wnt signaling-mediated PPAR gamma suppression was abolished by both the IWR-1 inhibitor and a small interfering RNA (siRNA) targeting beta-catenin and the Wnt coreceptor, LRP6. Both PEDF and the 34-mer down-regulated PDGF receptor-alpha/beta expression and blocked the PDGF-induced phosphorylation of Akt and ERK. Moreover, the inhibitory effect on PDGF receptor expression was abolished by PPAR gamma antagonists and PPAR gamma siRNA. Our observations indicate that the PEDF-derived 34-mer peptide can mimic PEDF in attenuating HSC activation. Investigation of this 34-mer peptide led to the identification of a signaling mechanism involving PPAR gamma induction, suppression of Wnt/beta-catenin signaling and down-regulation of the PDGF receptor-alpha/beta.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available