Interleukin-1 beta and transforming growth factor-beta 2 enhance cytosolic high-molecular-mass phospholipase A2 activity and induce prostaglandin E2 formation in rat mesangial cells.
Interleukin-1 beta induces gene expression and secretion of group-II phospholipase A2 and release of prostaglandin E2 from rat mesangial cells. The interleukin-1 beta-induced synthesis of group-II phospholipase A2 is prevented by transforming growth factor-beta 2, whereas transforming growth factor-beta 2 potentiated the interleukin-1 beta-evoked prostaglandin E2 production. Transforming growth factor-beta 2 itself did not induce synthesis of group-II phospholipase A2, although it stimulated prostaglandin E2 formation. Here we describe the effect of interleukin-1 beta and transforming growth factor-beta 2 on a cytosolic phospholipase A2 activity and prostaglandin E2 formation in rat mesangial cells. Based on the resistance to dithiothreitol and migration profiles on a Mono-Q anion-exchange column and a Superose 12 gel-filtration column, the cytosolic phospholipase A2 activity was assigned to a high-molecular-mass phospholipase A2. Measured with 1-stearoyl-2-[1-14C]arachidonoylglycero-phosphocholine as substrate, both interleukin-1 beta and transforming growth factor-beta 2 enhanced the high-molecular-mass phospholipase A2 activity. The stimulation of rat mesangial cells with interleukin-1 beta and transforming growth factor-beta 2 was time- and dose-dependent with maximal cytosolic phospholipase A2 activities at 10 nM and at 10 ng/ml respectively, after 24 h of stimulation. Under these conditions, interleukin-1 beta and transforming growth factor-beta 2 enhanced the cytosolic phospholipase A2 activity 2.2 +/- 0.6-fold and 2.5 +/- 0.6-fold, respectively. These results strongly suggest that an enhanced cytosolic high-molecular-mass phospholipase A2 activity is involved in the formation of prostaglandin E2 mediated by transforming growth factor-beta 2. Whether interleukin-1 beta induced group-II phospholipase A2 and/or interleukin-1 beta-enhanced cytosolic phospholipase A2 activity is involved in prostaglandin E2 formation in rat mesangial cells is discussed.
Schalkwijk
C G
CG
Centre for Biomembranes and Lipid Enzymology, Utrecht, The Netherlands.
de Vet
E
E
Pfeilschifter
J
J
van den Bosch
H
H
D000818:Animals; D002478:Cells, Cultured; D002850:Chromatography, Gel; D003600:Cytosol / Q000201:enzymology*; D015232:Dinoprostone / Q000096:biosynthesis*; D004789:Enzyme Activation; D005920:Glomerular Mesangium / Q000166:cytology / Q000378:metabolism*; D007375:Interleukin-1 / Q000494:pharmacology*; D010741:Phospholipases A / Q000378:metabolism*; D054467:Phospholipases A2; D051381:Rats; D016212:Transforming Growth Factor beta / Q000494:pharmacology*
D007375:Interleukin-1; D016212:Transforming Growth Factor beta; D010741:Phospholipases A; D054467:Phospholipases A2; D015232:Dinoprostone