Abstract
In response to pancreatic injury and in cell culture, pancreatic stellate cells (PSCs) are transformed (“activated”) into highly proliferative myofibroblast-like cells that express α-smooth muscle actin and produce extracellular matrix components. Activated PSCs are implicated in the pathogenesis of pancreatic fibrosis and inflammation. We here evaluated the effects of SP600125 (anthra[1,9-cd]pyrazole-6 (2H)-one), an inhibitor of c-Jun NH2-terminal kinase (JNK), on the activation of PSCs. PSCs were isolated from rat pancreas tissue and used in their culture-activated, myofibroblast-like phenotype unless otherwise stated. Activation of JNK was determined by Western blotting using anti-phosphospecific JNK and c-Jun antibodies. Activation of transcription factors was determined by electrophoretic mobility shift assay. The effects of SP600125 on the key parameters of activation (chemokine production, collagen production, and proliferation) were examined. The effect of SP600125 on the activation of freshly isolated PSCs in culture also was examined. Interleukin-1β activated both 46- and 54-kDa JNK, whereas platelet-derived growth factor-BB activated only 46-kDa JNK. SP600125 inhibited interleukin-1β-induced JNK activity and activator protein-1 activation, but it did not affect the activation of extracellular-regulated kinase, p38 mitogen-activated protein kinase, and nuclear factor-κB. SP600125 inhibited platelet-derived growth factor-induced proliferation, inducible monocyte chemoattractant protein-1 production, and serum-induced type I collagen production. Although SP600125 did not inhibit the transformation, it attenuated the proliferation of freshly isolated PSCs in culture. Collectively, our results suggest a role of JNK in the activation of PSCs, and a potential application of JNK inhibitors for the treatment of pancreatic fibrosis and inflammation.
Footnotes
-
This work was supported in part by Grant-in-Aid for Encouragement of Young Scientists from Japan Society for the Promotion of Science (to A.M.), by Pancreas Research Foundation of Japan (to A.M.), and by the Kanae Foundation for Life and Socio-Medical Science (to A.M.).
-
ABBREVIATIONS: PSC, pancreatic stellate cell; α-SMA, α-smooth muscle actin; MAP kinase, mitogen-activated protein kinase; ERK, extracellular signal-regulated kinase; JNK, c-Jun NH2-terminal kinase; AP-1, activator protein-1; NF-κB, nuclear factor-κB; PDGF, platelet-derived growth factor; SP600125, anthra[1,9-cd]pyrazole-6 (2H)-one; MTT, 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide; IL, interleukin; TNF, tumor necrosis factor; IκB, inhibitor of nuclear factor-κB; G3PDH, glyceraldehyde-3-phosphate dehydrogenase; SB203580, 4-(4-flurophenyl)-2-(4-methylsulfinylphenyl)-5-(4-pyridyl)imidazole; BrdU, bromo-2′-deoxyuridine; GFAP, glial fibrillary acidic protein; MCP-1, monocyte chemoattractant protein-1.
-
DOI: 10.1124/jpet.104.067280.
- Received February 19, 2004.
- Accepted March 31, 2004.
- The American Society for Pharmacology and Experimental Therapeutics
JPET articles become freely available 12 months after publication, and remain freely available for 5 years.Non-open access articles that fall outside this five year window are available only to institutional subscribers and current ASPET members, or through the article purchase feature at the bottom of the page.
|