Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P05412 (c-Jun)
 11,453 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Oxalate, a metabolic end product, is an important factor in the pathogenesis of renal stone disease. Oxalate exposure to renal epithelial cells results in re-initiation of the DNA synthesis, altered gene expression, and apoptosis, but the signaling pathways involved in these diverse effects have not been evaluated. The effects of oxalate on mitogen- and stress-activated protein kinase signaling pathways were studied in LLC-PK1 cells. Exposure to oxalate (1 mM) rapidly stimulated robust phosphorylation and activation of p38 MAPK. Oxalate exposure also induced modest activation of JNK, as monitored by phosphorylation of c-Jun. In contrast, oxalate exposure had no effect on phosphorylation and enzyme activity of p42/44 MAPK. We also show that specific inhibition of p38 MAPK by 4(4-(fluorophenyl)-2-(4-methylsulfonylphenyl)-5-(4-pyridyl)imidazole (SB203580) or by overexpression of a kinase-dead dominant negative mutant of p38 MAPK abolishes oxalate induced re-initiation of DNA synthesis in LLC-PK1 cells. The inhibition is dose-dependent and correlates with in situ activity of native p38 MAP kinase, determined as MAPK-activated protein kinase-2 activity in cell extracts. Thus, this study not only provides the first demonstration of selective activation of p38 MAPK and JNK signaling pathways by oxalate but also suggests that p38 MAPK activity is essential for the effects of oxalate on re-initiation of DNA synthesis.
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PMID:Oxalate selectively activates p38 mitogen-activated protein kinase and c-Jun N-terminal kinase signal transduction pathways in renal epithelial cells. 1182 57

Exposure of renal proximal tubule cells to oxalate may play an important role in cell proliferation, but the signaling pathways involved in this effect have not been elucidated. Thus the present study was performed to examine the effect of oxalate on (3)H-labeled thymidine incorporation and its related signal pathway in primary cultured rabbit renal proximal tubule cells (PTCs). The effects of oxalate on [(3)H]thymidine incorporation, lactate dehydrogenase (LDH) release, Trypan blue exclusion, H(2)O(2) release, activation of mitogen-activated protein kinases (MAPKs), and (3)H-labeled arachidonic acid (AA) release were examined in primary cultured renal PTCs. Oxalate inhibited [(3)H]thymidine incorporation in a time- and dose-dependent manner. However, its analogs did not affect [(3)H]thymidine incorporation. Oxalate (1 mM) significantly increased H(2)O(2) release, which was blocked by N-acetyl-l-cysteine (NAC) and catalase (antioxidants). Oxalate significantly increased p38 MAPK and stress-activated protein kinase (SAPK)/c-Jun NH(2)-terminal kinase (JNK) activity, not p44/42 MAPK. Oxalate stimulated [(3)H]AA release and translocation of cytosolic phospholipase A(2) (cPLA(2)) from the cytosolic fraction to the membrane fraction. Indeed, oxalate significantly increased prostaglandin E(2) (PGE(2)) production compared with control. Oxalate-induced inhibition of [(3)H]thymidine incorporation and increase of [(3)H]AA release were prevented by antioxidants (NAC), a p38 MAPK inhibitor (SB-203580), a SAPK/JNK inhibitor (SP-600125), or PLA(2) inhibitors [mepacrine and arachidonyl trifluoromethyl ketone (AACOCF(3))], but not by a p44/42 MAPK inhibitor (PD-98059). These findings suggest that oxalate inhibits renal PTC proliferation via oxidative stress, p38 MAPK/JNK, and cPLA(2) signaling pathways.
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PMID:Oxalate inhibits renal proximal tubule cell proliferation via oxidative stress, p38 MAPK/JNK, and cPLA2 signaling pathways. 1522 3