Product inhibition of secreted phospholipase A2 may explain lysophosphatidylcholines' unexpected therapeutic properties.
Product inhibition of secreted phospholipase A2 may explain lysophosphatidylcholines' unexpected therapeutic properties.
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DOI：
10.1186/1476-9255-5-17
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发表时间：
2008-10-22
影响因子：
5.1
通讯作者：
Lucena, Angel
中科院分区：
文献类型：
--
作者：
Cunningham, Timothy J.;Yao, Lihua;Lucena, Angel
溶血磷脂酰胆碱 (lysoPC) 是磷脂酶 A2 (PLA2) 酶活性的产物，与该酶一样，在多种器官系统的毒性炎症反应中具有直接作用。矛盾的是，脓毒症患者血浆 lysoPC 水平降低，而 lysoPC 的全身治疗对脓毒症和缺血的啮齿动物模型具有治疗作用。这些观察结果表明，这些脂质的血浆水平升高实际上可以帮助缓解严重的炎症状况。我们证明，特定的 lysoPC 作为血浆分泌的 PLA2 酶 (sPLA2) 的非竞争性产物抑制剂，特别是在酶活性升高的条件下，从而为观察到的这些化合物的抗炎作用提供了反馈机制。使用薄层色谱和质谱来估计大鼠血浆样品中总lysoPC浓度和不同lysoPC种类的相对贡献。对这些样品进行体外 sPLA2 酶活性的动力学研究，并在向反应混合物中添加特定的 lysoPC 物质后对体外纯化的 IA 组 sPLA2 进行动力学研究。还测量了注射了这些相同溶血PC的大鼠血浆样本中的酶活性。棕榈酰 (16:0)、硬脂酰 (18:0) 是大鼠血浆中最丰富的溶血 PC，与其他报道一致。动力学研究表明，两者都是血浆 sPLA2 酶活性的非竞争性抑制剂。 IA 组 sPLA2 的体外实验证实了这些 lysoPC 物种的抑制和动力学特性。血浆中未检测到的癸酰 lysoPC (10:0) 在体外不会抑制酶活性。将 LysoPC 注射到正常大鼠中会导致血浆 sPLA2 活性“缓冲”在一个狭窄的低范围内，这与离体和体外实验表明的活性依赖性抑制一致。该结果可以解释 lysoPC 疗法在炎症活动升高期间的功效，并进一步强调非竞争性酶抑制剂的效用。在这种情况下，抑制剂是酶反应的产物，因此代表了活动驱动的反馈抑制的一个例子。
Lysophosphatidylcholines (lysoPCs) are products of phospholipase A2 (PLA2) enzyme activity, and like the enzyme, have a direct role in toxic inflammatory responses in variety of organ systems. Paradoxically, reduced plasma lysoPC levels have been noted in sepsis patients and systemic treatment with lysoPCs is therapeutic in rodent models of sepsis and ischemia. These observations suggest that elevation of plasma levels of these lipids can actually help to relieve serious inflammatory conditions. We demonstrate that specific lysoPCs act as uncompetitive product inhibitors of plasma secreted PLA2 enzymes (sPLA2s), especially under conditions of elevated enzyme activity, thus providing a feedback mechanism for the observed anti-inflammatory effects of these compounds. Thin layer chromatography and mass spectroscopy were used to estimate total lysoPC concentration and the relative contributions of different lysoPC species in rat plasma samples. Kinetic studies of sPLA2 enzyme activity were conducted on these samples ex vivo and on purified group IA sPLA2 in vitro after addition of specific lysoPC species to the reaction mixture. Enzyme activity was also measured in plasma samples of rats injected with these same lysoPCs. Palmitoyl (16:0), stearoyl (18:0) are the most abundant lysoPCs in rat plasma consistent with other reports. Kinetic studies demonstrated that both were uncompetitive inhibitors of plasma sPLA2 enzyme activity. In vitro experiments with group IA sPLA2 confirmed the inhibition and the kinetic properties of these lysoPC species. Decanoyl lysoPC (10:0), which was not detected in plasma, did not inhibit enzyme activity in vitro. LysoPC injections into normal rats resulted in "buffering" of plasma sPLA2 activity in a narrow low range, consistent with the activity-dependent inhibition suggested by the ex vivo and in vitro experiments. The results may explain the efficacy of lysoPC therapy during periods of elevated inflammatory activity and further highlight the utility uncompetitive enzyme inhibitors. In this case, the inhibitor is a product of the enzyme reaction, and therefore represents an example of activity-driven feedback inhibition.
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DOI：
10.1080/01483918408067046
发表时间：
1984-01-01
期刊：
JOURNAL OF LIQUID CHROMATOGRAPHY
影响因子：
--
作者：
BARON, CB;COBURN, RF
通讯作者：
COBURN, RF
影响因子：
20.1
作者：
Fuentes, L;Hernández, M;Nieto, ML
通讯作者：
Nieto, ML
DOI：
10.1016/j.prostaglandins.2006.10.006
发表时间：
2007-02-01
影响因子：
2.9
作者：
Kim, Yu-Lee;Im, Young-Jin;Im, Dong-Soon
通讯作者：
Im, Dong-Soon
影响因子：
2.9
作者：
BERG, OG;YU, BZ;JAIN, MK
通讯作者：
JAIN, MK
影响因子：
9.3
作者：
Cunningham, Timothy J.;Yao, Lihua;Greenstein, Jeffrey I.
通讯作者：
Greenstein, Jeffrey I.