Pressure activates rat pancreatic stellate cells.
Pancreatic stellate cells (PSCs) play a central role in development of pancreatic fibrosis. In chronic pancreatitis, pancreatic tissue pressure is higher than that of the normal pancreas. We here evaluate the effects of pressure on the activation of rat PSCs. PSCs were isolated from the pancreas of Wistar rat using collagenase digestion and centrifugation with Nycodenz gradient. Pressure was applied to cultured rat PSCs by adding compressed helium gas into the pressure-loading apparatus to raise the internal pressure. Cell proliferation rate was assessed by 5-bromo-2'-deoxyuridine (BrdU) incorporation. MAPK protein levels and alpha-smooth muscle actin (alpha-SMA) expression were evaluated by Western blot analysis. Concentration of activated transforming growth factor-beta1 (TGF-beta1) secreted from PSCs into culture medium was determined by ELISA. Collagen type I mRNA expression and collagen secretion were assessed by quantitative PCR and Sirius red dye binding assay, respectively. Application of pressure significantly increased BrdU incorporation and alpha-SMA expression. In addition, pressure rapidly increased the phosphorylation of p44/42 and p38 MAPK. Treatment of PSCs with an MEK inhibitor and p38 MAPK inhibitor suppressed pressure-induced cell proliferation and alpha-SMA expression, respectively. Moreover, pressure significantly promoted activated TGF-beta1 secretion, collagen type I mRNA expression, and collagen secretion. Our results demonstrate that pressure itself activates rat PSCs and suggest that increased pancreatic tissue pressure may accelerate the development of pancreatic fibrosis in chronic pancreatitis.
Third Department of Internal Medicine, University of Occupational and Environmental Health, Japan, School of Medicine, 1-1 Iseigaoka, Yahatanishi-ku, Kitakyushu 807-8555, Japan.
Shiro
S
Watanabe
Yoshikuni
Y
Nagashio
Hiroshi
H
Asaumi
Yoko
Y
Nomiyama
Masashi
M
Taguchi
Mitsuo
M
Tashiro
Yasuyuki
Y
Kihara
Hayato
H
Nakamura
Makoto
M
Otsuki
D000199:Actins / Q000378:metabolism; D000818:Animals; D015153:Blotting, Western; D049109:Cell Proliferation / Q000187:drug effects; D002469:Cell Separation; D002478:Cells, Cultured; D003094:Collagen / Q000096:biosynthesis; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004797:Enzyme-Linked Immunosorbent Assay; D005109:Extracellular Matrix / Q000502:physiology; D005355:Fibrosis; D007093:Imidazoles / Q000494:pharmacology; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D009130:Muscle, Smooth / Q000378:metabolism; D010179:Pancreas / Q000166:cytology* / Q000473:pathology / Q000502:physiology*; D010812:Physical Stimulation; D011312:Pressure; D011725:Pyridines / Q000494:pharmacology; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016212:Transforming Growth Factor beta / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors
D000199:Actins; D004791:Enzyme Inhibitors; D007093:Imidazoles; D011725:Pyridines; D012333:RNA, Messenger; D016212:Transforming Growth Factor beta; D003094:Collagen; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; C093642:SB 203580