Osteopontin Inhibits Interleukin-1β-stimulated Increases in Matrix Metalloproteinase Activity in Adult Rat Cardiac Fibroblasts
Osteopontin Inhibits Interleukin-1β-stimulated Increases in Matrix Metalloproteinase Activity in Adult Rat Cardiac Fibroblasts
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DOI：
10.1074/jbc.m302727200
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发表时间：
2002-04
影响因子：
4.8
通讯作者：
Zhonglin Xie;Mahipal Singh;D. Siwik;W. L. Joyner;Krishna Singh
中科院分区：
文献类型：
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作者：
Zhonglin Xie;Mahipal Singh;D. Siwik;W. L. Joyner;Krishna Singh
我们已经证明骨桥蛋白（OPN）是一种细胞外基质蛋白，通过促进胶原蛋白的合成和积累，在心肌梗死（MI）后重塑中发挥重要作用。 MI 后心脏中的白细胞介素-1β (IL-1β) 增加，体外增加心脏成纤维细胞中的基质金属蛋白酶 (MMP) 活性。在这里，我们表明 OPN 单独对 MMP 活性或表达没有影响。然而，它会减少成年大鼠心脏成纤维细胞中 IL-1β 刺激的 MMP 活性和表达的增加。牛血清白蛋白预处理对 MMP 活性或蛋白质含量没有影响，而 GRGDS（甘氨酸-精氨酸-甘氨酸-天冬氨酸-丝氨酸）五肽（可中断含有 RGD 的蛋白质与细胞表面整合素的结合）和单克隆抗体 m7E3（大鼠 β3 整合素拮抗剂）抑制 OPN 的作用。使用白屈菜赤碱抑制 PKC 会抑制 MMP-2 和 MMP-9 的活性。使用 IL-1β 刺激细胞会增加 PKC 的磷酸化和易位至膜组分，而 OPN 会抑制这种作用。 OPN 抑制 IL-1β 刺激的 PKC-ze 从胞质部分向膜部分易位的增加。此外，MI 后 6 天，与野生型相比，OPN 敲除小鼠心脏的胞质部分中磷酸-PKC-ζ 的水平较低。使用 PKC-ze 假底物抑制 PKC-ze 可抑制 IL-1β 刺激的 MMP-2 和 MMP-9 活性增加。这些观察结果表明，OPN 通过 β3 整合素发挥作用，抑制 IL-1β 刺激的 MMP-2 和 MMP-9 活性增加，至少部分是通过 PKC-ζ 的参与。因此，OPN 可能通过调节细胞因子刺激的 MMP 活性，在 MI 后心肌重塑过程中的胶原蛋白沉积中发挥关键作用。
We have shown that osteopontin (OPN), an extracellular matrix protein, plays an important role in post myocardial infarction (MI) remodeling by promoting collagen synthesis and accumulation. Interleukin-1β (IL-1β), increased in the heart following MI, increases matrix metalloproteinase (MMP) activity in cardiac fibroblasts in vitro. Here, we show that OPN alone has no effect on MMP activity or expression. However, it reduces IL-1β-stimulated increases in MMP activity and expression in adult rat cardiac fibroblasts. Pretreatment with bovine serum albumin had no effect on MMP activity or protein content, whereas GRGDS (glycine-arginine-glycine-aspartic acid-serine)-pentapeptide (which interrupts binding of RGD-containing proteins to cell surface integrins) and monoclonal antibody m7E3 (a rat β3 integrins antagonist) inhibited the effects of OPN. Inhibition of PKC using chelerythrine inhibited the activities of both MMP-2 and MMP-9. Stimulation of cells using IL-1β increased phosphorylation and translocation of PKC to membrane fractions, which was inhibited by OPN. OPN inhibited IL-1β-stimulated increases in translocation of PKC-ζ from cytosolic to membrane fractions. Furthermore, the levels of phospho-PKC-ζ were lower in the cytosolic fractions of OPN knock-out mice hearts as compared with wild type 6 days post-MI. Inhibition of PKC-ζ using PKC-ζ pseudosubstrate inhibited IL-1β-stimulated increases in MMP-2 and MMP-9 activities. These observations suggest that OPN, acting via β3 integrins, inhibits IL-1β-stimulated increases in MMP-2 and MMP-9 activity, at least in part, via the involvement of PKC-ζ. Thus, OPN may play a key role in collagen deposition during myocardial remodeling following MI by modulating cytokine-stimulated MMP activity.