Premium
Ca 2+ /calmodulin‐ dependent protein kinase II mediates transforming growth factor‐β‐induced hepatic stellate cells proliferation but not in collagen α1(I) production
Author(s) -
An Ping,
Tian Yihao,
Chen Mingkai,
Luo Hesheng
Publication year - 2012
Publication title -
hepatology research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.123
H-Index - 75
eISSN - 1872-034X
pISSN - 1386-6346
DOI - 10.1111/j.1872-034x.2012.00983.x
Subject(s) - hepatic stellate cell , microbiology and biotechnology , chemistry , smad , growth factor , protein kinase b , transforming growth factor beta , transforming growth factor , signal transduction , cell growth , biology , endocrinology , biochemistry , receptor
Aim: Hepatic stellate cells (HSC) are the major players in hepatic fibrosis. As a most potent mitogen, transforming growth factor‐β (TGF‐β) strongly activates HSC and increases intracellular Ca 2+ concentration. Here, we assessed the potential role of Ca 2+ /calmodulin‐dependent protein kinase II (CaMKII), a main downstream effector of the Ca 2+ signal in liver fibrogenesis cascade. Methods: A human immortal HSC cell line, LX‐2, and primary rat hepatic stellate cells were used in current study. CaMKII blockage and Akt inhibition were performed by KN‐93/CaMKIIα siRNA and LY294002, respectively. HSC proliferation was detected by 5‐bromodeoxyuridine incorporation assay. Real‐time polymerase chain reaction, western blot and enzyme‐linked immunosorbent assay were used to measure mRNA, cellular protein and protein in medium, respectively. Procollagen α1(I) expression was detected by immunocytochemistry. The role of CaMKII on TGF‐β/Smad‐induced collagen α1(I) expression was determined by (CAGA) 12 ‐MLP luciferase activity assay. Results: TGF‐β dramatically increased CaMKII mRNA, and total and phosphorylated CaMKII expression. KN‐93 and CaMKIIα siRNA suppressed TGF‐β‐mediated HSC proliferation. CaMKII interruption blocked TGF‐β‐elicited Akt activation. LY294002 arrested HSC proliferation and collagen α1(I) production but had no effect on CaMKII. Furthermore, CaMKII led to increased p21 and p27 expression. KN‐93 and CaMKIIα siRNA inhibited TGF‐β‐induced and basal collagen α1(I) production but had no effect on the activity of (CAGA) 12 ‐MLP luciferase in response to TGF‐β stimulation. Conclusion: CaMKII is a pivotal signal in TGF‐β‐induced fibrogenic cascades by means of stimulating HSC proliferation, and involved in a basal collagen production. Therefore, CaMKII will be a potentially effective target in the development of therapeutic intervention strategies to attenuate hepatic fibrosis.