RGD Reference Report - Smad2 and Smad3 play different roles in rat hepatic stellate cell function and alpha-smooth muscle actin organization. - Rat Genome Database
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Smad2 and Smad3 play different roles in rat hepatic stellate cell function and alpha-smooth muscle actin organization.

Authors: Uemura, M  Swenson, ES  Gaca, MD  Giordano, FJ  Reiss, M  Wells, RG 
Citation: Uemura M, etal., Mol Biol Cell. 2005 Sep;16(9):4214-24. Epub 2005 Jun 29.
RGD ID: 2300418
Pubmed: (View Article at PubMed) PMID:15987742
DOI: Full-text: DOI:10.1091/mbc.E05-02-0149

Hepatic stellate cells (HSC) play a central role in the pathogenesis of liver fibrosis, transdifferentiating in chronic liver disease from "quiescent" HSC to fibrogenic myofibroblasts. Transforming growth factor-beta (TGF-beta), acting both directly and indirectly, is a critical mediator of this process. To characterize the function of the TGF-beta signaling intermediates Smad2 and Smad3 in HSC, we infected primary rat HSC in culture with adenoviruses expressing wild-type and dominant negative Smads 2 and 3. Smad3-overexpressing cells exhibited increased deposition of fibronectin and type 1 collagen, increased chemotaxis, and decreased proliferation compared with uninfected cells and those infected with Smad2 or either dominant negative, demonstrating different biological functions for the two Smads. Additionally, coinfection experiments suggested that Smad2 and Smad3 signal via independent pathways. Smad3-overexpressing cells as well as TGF-beta-treated cells demonstrated more focal adhesions and increased alpha-smooth muscle actin (alpha-SMA) organization in stress fibers, although all cells reached the same level of alpha-SMA expression, indicating that Smad3 also regulates cytoskeletal organization in HSC. We suggest that TGF-beta, signaling via Smad3, plays an important role in the morphological and functional maturation of hepatic myofibroblasts.

Annotation

Gene Ontology Annotations    

Objects Annotated

Genes (Rattus norvegicus)
Smad2  (SMAD family member 2)
Smad3  (SMAD family member 3)


Additional Information