Characterization of FKGK18 as inhibitor of group VIA Ca2+-independent phospholipase A2 (iPLA2β): candidate drug for preventing beta-cell apoptosis and diabetes.
Characterization of FKGK18 as inhibitor of group VIA Ca2+-independent phospholipase A2 (iPLA2β): candidate drug for preventing beta-cell apoptosis and diabetes.
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DOI：
10.1371/journal.pone.0071748
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发表时间：
2013
期刊：
影响因子：
3.7
通讯作者：
Ramanadham S
中科院分区：
文献类型：
--
作者：
Ali T;Kokotos G;Magrioti V;Bone RN;Mobley JA;Hancock W;Ramanadham S
正在进行的研究表明，iPLA 2 β在许多生物学过程中发挥重要作用，并与神经退行性疾病、骨骼和血管平滑肌疾病、骨形成和心律失常有关。因此，有必要确定一种可以可靠和安全地在体内使用的iPLA 2 β抑制剂。目前，基于机制的抑制剂溴烯醇内酯（BEL）是最广泛用于识别iPLA 2 β在生物过程中的作用。虽然BEL被认为是比cPLA 2或sPLA 2更有效的iPLA 2抑制剂，导致其被指定为iPLA 2的“特异性”抑制剂，但已显示其也抑制非PLA 2酶。其使用的一个潜在的复杂性是，虽然BEL的S和R对映体分别表现出对细胞溶胶相关的iPLA 2 β和膜相关的iPLA 2 γ的偏好，但对两者的选择性仅为10倍。此外，BEL在溶液中不稳定，促进不可逆抑制，并且可能具有细胞毒性，使得BEL不适合体内使用。最近，一种基于氟酮（FK）的化合物（FKGK 18）被描述为iPLA 2 β的有效抑制剂。在此，我们表征了FKGK 18在β细胞中的抑制特性，发现FKGK 18：（a）以更大的效力抑制iPLA 2 β（B）iPLA 2 β的抑制是可逆的，（c）是α-胰凝乳蛋白酶的无效抑制剂，和（d）抑制先前描述的iPLA 2 β活化的结果，包括（i）葡萄糖刺激的胰岛素分泌，（ii）花生四烯酸水解;如从人胰岛释放PGE 2所反映的，（iii）ER应激诱导的中性鞘磷脂酶2表达，和（iv）ER应激诱导的β-细胞凋亡。这些结果表明，FKGK 18在抑制iPLA 2 β的能力方面与BEL相似。因为与BEL相反，它是可逆的，不是蛋白酶的非特异性抑制剂，所以表明FKGK 18对于iPLA 2 β在生物学功能中的作用的离体和体内评估更理想。
Ongoing studies suggest an important role for iPLA2β in a multitude of biological processes and it has been implicated in neurodegenerative, skeletal and vascular smooth muscle disorders, bone formation, and cardiac arrhythmias. Thus, identifying an iPLA2βinhibitor that can be reliably and safely used in vivo is warranted. Currently, the mechanism-based inhibitor bromoenol lactone (BEL) is the most widely used to discern the role of iPLA2β in biological processes. While BEL is recognized as a more potent inhibitor of iPLA2 than of cPLA2 or sPLA2, leading to its designation as a “specific” inhibitor of iPLA2, it has been shown to also inhibit non-PLA2 enzymes. A potential complication of its use is that while the S and R enantiomers of BEL exhibit preference for cytosol-associated iPLA2β and membrane-associated iPLA2γ, respectively, the selectivity is only 10-fold for both. In addition, BEL is unstable in solution, promotes irreversible inhibition, and may be cytotoxic, making BEL not amenable for in vivo use. Recently, a fluoroketone (FK)-based compound (FKGK18) was described as a potent inhibitor of iPLA2β. Here we characterized its inhibitory profile in beta-cells and find that FKGK18: (a) inhibits iPLA2β with a greater potency (100-fold) than iPLA2γ, (b) inhibition of iPLA2β is reversible, (c) is an ineffective inhibitor of α-chymotrypsin, and (d) inhibits previously described outcomes of iPLA2β activation including (i) glucose-stimulated insulin secretion, (ii) arachidonic acid hydrolysis; as reflected by PGE2 release from human islets, (iii) ER stress-induced neutral sphingomyelinase 2 expression, and (iv) ER stress-induced beta-cell apoptosis. These findings suggest that FKGK18 is similar to BEL in its ability to inhibit iPLA2β. Because, in contrast to BEL, it is reversible and not a non-specific inhibitor of proteases, it is suggested that FKGK18 is more ideal for ex vivo and in vivo assessments of iPLA2β role in biological functions.
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影响因子：
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