Autocrine loop between TGF-beta1 and IL-1beta through Smad3- and ERK-dependent pathways in rat pancreatic stellate cells.
Pancreatic stellate cells (PSCs) are activated during pancreatitis and promote pancreatic fibrosis by producing and secreting ECMs such as collagen and fibronectin. IL-1beta has been assumed to participate in pancreatic fibrosis by activating PSCs. Activated PSCs secrete various cytokines that regulate PSC function. In this study, we have examined IL-1beta secretion from culture-activated PSCs as well as its regulatory mechanism. RT-PCR and ELISA have demonstrated that PSCs express IL-1beta mRNA and secrete IL-1beta peptide. Inhibition of TGF-beta(1) activity secreted from PSCs by TGF-beta(1)-neutralizing antibody attenuated IL-1beta secretion from PSCs. Exogenous TGF-beta(1) increased IL-1beta expression and secretion by PSCs in a dose-dependent manner. Adenovirus-mediated expression of dominant-negative (dn)Smad2/3 expression reduced both basal and TGF-beta(1)-stimulated IL-1beta expression and secretion by PSCs. Coexpression of Smad3 with dnSmad2/3 restored IL-1beta expression and secretion by PSCs, which were attenuated by dnSmad2/3 expression. In contrast, coexpression of Smad2 with dnSmad2/3 did not alter them. Furthermore, inhibition of IL-1beta activity secreted from PSCs by IL-1beta-neutralizing antibody attenuated TGF-beta(1) secretion from PSCs. Exogenous IL-1beta enhanced TGF-beta(1) expression and secretion by PSCs. IL-1beta activated ERK, and PD-98059, a MEK1 inhibitor, blocked IL-1beta enhancement of TGF-beta(1) expression and secretion by PSCs. We propose that an autocrine loop exists between TGF-beta(1) and IL-1beta in activated PSCs through Smad3- and ERK-dependent pathways.
Aoki
Hiroyoshi
H
Department of Gastroenterology, Jichi Medical School, 3311-1 Yakushiji, Kawachi-gun, Tochigi 329-0498, Japan.
Ohnishi
Hirohide
H
Hama
Kouji
K
Ishijima
Takako
T
Satoh
Yukihiro
Y
Hanatsuka
Kazunobu
K
Ohashi
Akira
A
Wada
Shinichi
S
Miyata
Tomohiko
T
Kita
Hiroto
H
Yamamoto
Hironori
H
Osawa
Hiroyuki
H
Sato
Kiichi
K
Tamada
Kiichi
K
Yasuda
Hiroshi
H
Mashima
Hirosato
H
Sugano
Kentaro
K
D000818:Animals; D000906:Antibodies / Q000378:metabolism; D019898:Autocrine Communication; D002478:Cells, Cultured; D004791:Enzyme Inhibitors / Q000378:metabolism; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism*; D005419:Flavonoids / Q000378:metabolism; D007375:Interleukin-1 / Q000235:genetics / Q000378:metabolism*; D010179:Pancreas / Q000166:cytology* / Q000378:metabolism; D051381:Rats; D015398:Signal Transduction / Q000502:physiology; D051899:Smad2 Protein / Q000235:genetics / Q000378:metabolism; D051900:Smad3 Protein / Q000235:genetics / Q000378:metabolism*; D016212:Transforming Growth Factor beta / Q000235:genetics / Q000378:metabolism*; D053773:Transforming Growth Factor beta1
D000906:Antibodies; D004791:Enzyme Inhibitors; D005419:Flavonoids; D007375:Interleukin-1; D051899:Smad2 Protein; C497784:Smad2 protein, rat; D051900:Smad3 Protein; C497787:Smad3 protein, rat; C508962:Tgfb1 protein, rat; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; D048049:Extracellular Signal-Regulated MAP Kinases; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one