Schalkwijk C G, de Vet E, Pfeilschifter J, van den Bosch H
Centre for Biomembranes and Lipid Enzymology, Utrecht, The Netherlands.
Eur J Biochem. 1992 Nov 15;210(1):169-76. doi: 10.1111/j.1432-1033.1992.tb17405.x.
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.
白细胞介素-1β可诱导大鼠系膜细胞中II型磷脂酶A2的基因表达和分泌，并促使前列腺素E2释放。转化生长因子-β2可抑制白细胞介素-1β诱导的II型磷脂酶A2合成，而转化生长因子-β2可增强白细胞介素-1β诱发的前列腺素E2生成。转化生长因子-β2自身虽可刺激前列腺素E2生成，但不会诱导II型磷脂酶A2的合成。在此，我们描述了白细胞介素-1β和转化生长因子-β2对大鼠系膜细胞胞质磷脂酶A2活性及前列腺素E2生成的影响。基于对二硫苏糖醇的抗性以及在Mono-Q阴离子交换柱和Superose 12凝胶过滤柱上的迁移图谱，将胞质磷脂酶A2活性归为一种高分子量磷脂酶A2。以1-硬脂酰-2-[1-14C]花生四烯酰甘油磷脂胆碱为底物进行测定，白细胞介素-1β和转化生长因子-β2均可增强高分子量磷脂酶A2活性。用白细胞介素-1β和转化生长因子-β2刺激大鼠系膜细胞具有时间和剂量依赖性，刺激24小时后，分别在10 nM和10 ng/ml时胞质磷脂酶A2活性达到最大值。在这些条件下，白细胞介素-1β和转化生长因子-β2分别使胞质磷脂酶A2活性增强2.2±0.6倍和2.5±0.6倍。这些结果有力地表明，增强的胞质高分子量磷脂酶A2活性参与了转化生长因子-β2介导的前列腺素E2形成。文中还讨论了白细胞介素-1β诱导的II型磷脂酶A2和/或白细胞介素-1β增强的胞质磷脂酶A2活性是否参与大鼠系膜细胞中前列腺素E2的形成。
