Laboratoire de Biochimie et de Biologie Cellulaire, Faculté de Pharmacie, Université Paris Sud-11, Chatenay-Malabry Cedex, France.
Basic Clin Pharmacol Toxicol. 2012 Nov;111(5):296-302. doi: 10.1111/j.1742-7843.2012.00906.x. Epub 2012 Jul 6.
Pleiotrophin, also known as heparin affin regulatory peptide (HARP), is a growth factor expressed in various tissues and cell lines. In this work, HARP was tested for its capacity to modulate the anticoagulant activity of heparin and heparan sulphate mimetics (OTR4120). We used both in vitro and in vivo assays. HARP was found to be differently effective for neutralization of the anticoagulant activity of the mimetic heparan sulphate (OTR4120) and heparin in purified system and human plasma. HARP was shown to compete with both antithrombin and thrombin for binding to heparin and to OTR4120, respectively. In the presence of OTR4120, the V(max) was constant and the calculated maximum velocity was 1.56 U/min; the thrombin Km value (0.011 nM) was affected by HARP concentrations. The Km (HARP) value was 0.085 nM, which is consistent with high affinity of HARP to OTR4120. Under the same conditions, initial velocity patterns for antithrombin-heparin were determined in the presence or in the absence of HARP. The antithrombin value Km (0.022 nM) was affected by HARP (0.077 nM). HARP exhibits efficacy equivalent to or greater than protamine. Interestingly, intraperitoneally administered HARP decreased the anticoagulant activity of heparin and of OTR4120 in mice. Taken together, these data provide the first evidence for a physiological role of HARP in the modulation of anticoagulant activity of heparin and heparin-like material.
多效蛋白（也称为肝素亲和调节肽，HARP）是一种在各种组织和细胞系中表达的生长因子。在这项工作中，我们测试了 HARP 调节肝素和肝素类似物（OTR4120）抗凝活性的能力。我们使用了体外和体内检测方法。结果发现，HARP 在纯化系统和人血浆中对模拟肝素硫酸乙酰肝素（OTR4120）和肝素抗凝活性的中和作用具有不同的效果。HARP 被证明可分别与抗凝血酶和凝血酶竞争结合肝素和 OTR4120。在 OTR4120 存在的情况下，Vmax 保持不变，计算出的最大速度为 1.56 U/min；凝血酶 Km 值（0.011 nM）受 HARP 浓度的影响。Km（HARP）值为 0.085 nM，这与 HARP 对 OTR4120 的高亲和力一致。在相同条件下，确定了存在或不存在 HARP 时抗凝血酶-肝素的初始速度模式。抗凝血酶 Km 值（0.022 nM）受 HARP（0.077 nM）的影响。HARP 的功效与鱼精蛋白相当或更高。有趣的是，腹腔内给予 HARP 可降低肝素和 OTR4120 在小鼠中的抗凝活性。综上所述，这些数据首次提供了 HARP 在调节肝素和肝素样物质抗凝活性方面具有生理作用的证据。
