NP-313, 2-acetylamino-3-chloro-1,4-naphthoquinone, a novel antithrombotic agent with dual inhibition of thromboxane A(2) synthesis and calcium entry

作者：Kuo Heng Lan; Lien Jin Cherng; Chang Chien Hsin; Chung Ching Hu; Kuo Sheng Chu; Hsu Chun Chieh; Peng Hui Chin; Huang Tur Fu^*

来源：British Journal of Pharmacology, 2011, 162(8): 1871-1883.

DOI：10.1111/j.1476-5381.2011.01200.x

• antiplatelet
• naphthoquinone
• store-operated calcium channel
• thromboxane A(2) synthesis

BACKGROUND AND PURPOSE
1,4-Naphthoquinones exhibit antiplatelet activity both in vivo and in vitro. In the present study, we investigated the antiplatelet effect of a novel naphthoquinone derivative NP-313, 2-acetylamino-3-chloro-1,4-naphthoquinone and its mechanism of action.
EXPERIMENTAL APPROACH
We measured platelet aggregation, Ca2+ mobilization, thromboxane B-2 formation and P-selectin expression and examined several enzymatic activities. Furthermore, we used the irradiated mesenteric venules in fluorescein sodium-treated mice to monitor the antithrombotic effect of NP-313 in vivo.
KEY RESULTS
NP-313 concentration-dependently inhibited human platelet aggregation induced by collagen, arachidonic acid, thapsigargin, thrombin and A23187. NP-313 also inhibited P-selectin expression, thromboxane B-2 formation and [Ca2+](i) elevation in platelets stimulated by thrombin and collagen. NP-313 at 10 mu M inhibited cyclooxygenase, thromboxane A(2) synthase, and protein kinase C alpha, whereas it did not affect phospholipase A(2) or phospholipase C activity. In the presence of indomethacin and an adenosine 5-diphosphate scavenger, NP-313 concentration-dependently inhibited thrombin-and A23187-induced [Ca2+](i) increase through its inhibitory effects on Ca2+ influx, rather than blocking Ca2+ release from intracellular stores. NP-313 also inhibited thapsigargin-mediated Ca2+ influx through store-operated calcium channel but had no effect on Ca2+ influx through store-independent calcium channel evoked by the diacylglycerol analogue 1-oleoyl-2-acetyl-sn-glycerol. Nevertheless, it had little effect on cyclic AMP and cyclic GMP levels. Also, intravenously administered NP-313 dose-dependently inhibited the thrombus occlusion of the irradiated mesenteric vessels of fluorescein-pretreated mice.
CONCLUSIONS AND IMPLICATIONS
Taken together, these results indicate that NP-313 exerts its antithrombotic activity through dual inhibition of thromboxane A(2) synthesis and Ca2+ influx through SOCC.

• 出版日期2011-4
• 单位中国医科大学