Increased Smad1 expression and transcriptional activity enhances trans-differentiation of hepatic stellate cells.
Smad1 is a receptor-activated intracellular signaling protein, which mediates signal transduction of bone morphogenetic proteins. Current study investigated the expression and transcriptional activity of Smad1 during hepatic stellate cell (HSC) activation. Rat HSCs were isolated from rats at 1, 2, 3 and 4 days after gavaged with carbon tetrachloride (CCl(4)) or corn oil. RT-PCR, Western blot, gel-shift assay and luciferase assay were employed to examine Smad1 expression and transcriptional activity, respectively. CCl(4)-cirrhotic liver fat-storing cells-8B (CFSC-8B) cells were infected with recombinant adenoviruses of Smad1 and/or Smad1 shRNA. Both mRNA and protein levels of Smad1 were significantly increased at 48 h after gavage of CCl(4). Gel shift assays demonstrated a significant increase in nuclear Smad1 in day 9 HSCs. Transfection of HSCs with Smad1 responsible luciferase indicated an increase in Smad1 transcriptional activity in day 6 HSCs (1.563 +/- 0.229 in day 6 versus 0.785 +/- 0.192 in day 3). When CFSC-8B cells were infected with adenoviruses with Smad1 or Smad1 short hairpin RNA (shRNA), there was an increase or decrease in Smad1 mRNA and protein, respectively. Smooth muscle alpha-actin expression was increased or decreased according to induction or reduction of Smad1. In conclusion, there were significantly increases in Smad1 expression and transcriptional activity during in vivo activation of hepatic stellate cells.
Shen
Hong
H
Medical Research Center, Xiangya Hospital, Central South University, Changsha, Hunan, China.
Fan
Jianghong
J
Burczynski
Frank
F
Minuk
Gerald Y
GY
Cattini
Peter
P
Gong
Yuewen
Y
D000199:Actins / Q000378:metabolism; D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D002251:Carbon Tetrachloride; D002454:Cell Differentiation / Q000235:genetics; D002460:Cell Line; D049109:Cell Proliferation; D004195:Disease Models, Animal; D005822:Genetic Vectors; D008099:Liver / Q000378:metabolism* / Q000473:pathology; D008103:Liver Cirrhosis / Q000139:chemically induced / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D008297:Male; D010641:Phenotype; D034622:RNA Interference; D012333:RNA, Messenger / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D051898:Smad1 Protein / Q000235:genetics / Q000378:metabolism*; D013997:Time Factors; D014158:Transcription, Genetic; D014162:Transfection; D015854:Up-Regulation
D000199:Actins; D002251:Carbon Tetrachloride; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D051898:Smad1 Protein; C497400:Smad1 protein, rat; C498862:Acta2 protein, rat