Epimorphin, a morphogenic protein, induces proteases in rodent hepatocytes through NF-kappaB.
OBJECTIVE
Epimorphin, expressed by hepatic stellate cells in the liver, directs normal morphogenesis in various organs. The aim of this study was to clarify the mechanism by which epimorphin functions as a morphogen in vitro.


METHODS
Male Balb/c mice and Sprague-Dawley rats were used. First, we explored the relationship between epimorphin expression and distribution of protease-positive cells in carbon tetrachloride-induced acute liver injury. We then examined protease levels in cultured hepatocytes and signal transduction of epimorphin. Finally, we determined the requirement for proteases and NF-kappaB in spheroid formation induced by epimorphin.


RESULTS
Epimorphin expression was enhanced in injured areas during late recovery phase, in which protease-positive hepatocytes were localized adjacent to epimorphin-expressing cells. In vitro, epimorphin induced matrix metalloproteinase (MMP) 9, MMP 3 and urokinase type plasminogen activator (uPA) in hepatocytes. NF-kappaB mediated these protease expressions in hepatocytes. These proteases were required for epimorphin-induced and Matrigel induced spheroid. An epimorphin-neutralizing antibody also blocked spheroid formation on Matrigel, which contained epimorphin. In addition, NF-kappaB activation was also required for spheroid formation.


CONCLUSIONS
Epimorphin elicits hepatocyte spheroids by inducing proteases in rodent hepatocytes through NF-kappaB.
Miura
Kouichi
K
Department of Gastroenterology, Akita University School of Medicine, 1-1-1 Hondo, Akita 010-8543, Japan.
Yoshino
Ryutaro
R
Hirai
Yohei
Y
Goto
Takashi
T
Ohshima
Shigetoshi
S
Mikami
Ken-Ichiro
K
Yoneyama
Kazuo
K
Watanabe
Daisuke
D
Sato
Mitsuru
M
Senoo
Haruki
H
Kodama
Yuzo
Y
Osawa
Yosuke
Y
Brenner
David A
DA
Watanabe
Sumio
S
D000818:Animals; D002251:Carbon Tetrachloride; D018920:Coculture Techniques; D005786:Gene Expression Regulation; D022781:Hepatocytes / Q000201:enzymology*; D008099:Liver / Q000166:cytology; D008103:Liver Cirrhosis / Q000139:chemically induced / Q000201:enzymology / Q000473:pathology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D016328:NF-kappa B / Q000378:metabolism*; D010447:Peptide Hydrolases / Q000235:genetics*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction; D018874:Spheroids, Cellular; D050827:Syntaxin 1 / Q000502:physiology*
D016328:NF-kappa B; D050827:Syntaxin 1; D002251:Carbon Tetrachloride; D010447:Peptide Hydrolases