title: Longistatin, a novel plasminogen activator from vector ticks, is resistant to plasminogen activator inhibitor-1.
abstract: Thrombo-occlusive diseases are major causes of morbidity and mortality, and tissue-type plasminogen activator (t-PA) is recommended for the treatment of the maladies. However, both t-PA and u-PA are rapidly inactivated by plasminogen activator inhibitor-1 (PAI-1). Here, we show that longistatin, a novel plasminogen activator isolated from the ixodid tick, Haemaphysalis longicornis is resistant to PAI-1. Longistatin was relatively less susceptible to the inhibitory effect of SDS-treated platelet lysate than physiologic PAs. Platelet lysate inhibited t-PA and tcu-PA with the IC(50) of 7.7 and 9.1 μg/ml, respectively, whereas for longistatin inhibition IC(50) was 20.1 μg/ml (p<0.01). Similarly, activated PAI-1 (20 nM) inhibited only 21.47% activity of longistatin but almost completely inhibited t-PA (99.17%) and tcu-PA (96.84%). Interestingly, longistatin retained 76.73% initial activity even after 3h of incubation with 20 nM of PAI-1. IC(50) of PAI-1 during longistatin inhibition was 88.3 nM while it was 3.9 and 3.2 nM in t-PA and tcu-PA inhibition, respectively. Longistatin completely hydrolyzed fibrin clot by activating plasminogen efficiently in the presence of 20 nM of PAI-1. Importantly, unlike t-PA, longistatin did not form complex with PAI-1. Collectively, our results suggest that longistatin is resistant to PAI-1 and maybe an interesting tool for the development of a PAI-1 resistant effective thrombolytic agent.
authors.affiliation: Department of Global Agricultural Sciences, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo, Tokyo, Japan.
authors.lastname: Anisuzzaman
authors.forename: M
authors.initials: M
authors.lastname: Khyrul Islam
authors.forename: M
authors.initials: M
authors.lastname: Abdul Alim
authors.forename: Takeharu
authors.initials: T
authors.lastname: Miyoshi
authors.forename: Takeshi
authors.initials: T
authors.lastname: Hatta
authors.forename: Kayoko
authors.initials: K
authors.lastname: Yamaji
authors.forename: Yasunobu
authors.initials: Y
authors.lastname: Matsumoto
authors.forename: Kozo
authors.initials: K
authors.lastname: Fujisaki
authors.forename: Naotoshi
authors.initials: N
authors.lastname: Tsuji
mesh_terms: D000818:Animals; D002135:Calcium-Binding Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D002478:Cells, Cultured; D004199:Disease Vectors; D005337:Fibrin / Q000378:metabolism; D006801:Humans; D018884:Ixodes / Q000378:metabolism*; D017395:Plasminogen Activator Inhibitor 1 / Q000378:metabolism*; D010960:Plasminogen Activators / Q000378:metabolism*; D012471:Salivary Proteins and Peptides / Q000037:antagonists & inhibitors / Q000378:metabolism*
chemical_list: D002135:Calcium-Binding Proteins; D017395:Plasminogen Activator Inhibitor 1; C051321:SERPINE1 protein, human; D012471:Salivary Proteins and Peptides; C559189:longistatin protein, Haemaphysalis longicornis; D005337:Fibrin; D010960:Plasminogen Activators