Abstract
Thrombolysis is the gold standard treatment for acute ischemic stroke. Besides its fibrinolytic role, recombinant tissue plasminogen activator (r-tPA) holds several non-fibrinolytic functions. Here, we investigated the potential role of r-tPA on human primary neutrophil migration in vitro. By means of modified Boyden chamber migration assay and checkerboard analysis we showed a dose-dependent chemotactic effect of r-TPA with a maximum effect reached by 0.03 mg/mL (0.003–1 mg/mL). Pre-incubation with MAP kinases inhibitors allowed the identification of PI3K/Akt, but not ERK1/2 as the intracellular pathway mediating the observed effects. Furthermore, by means of real-time PCR, immunocytochemistry and cytofluorimetry we demonstrated that the r-tPA receptor low density lipoprotein receptor-related protein 1 (LRP-1) is synthetized and expressed by neutrophils in response to r-tPA and TNF-α. Inhibition of LRP-1 by receptor-associated protein (RAP), prevented r-tPA-mediated F-actin polymerization, migration and signal through Akt but not ERK1/2. Lastly, also neutrophil degranulation in response to r-tPA seems to be mediated by LRP-1 under adhesion conditions. In conclusion, we show that r-tPA induces neutrophil chemotaxis through LRP-1/Akt pathway. Blunting r-tPA-mediated neutrophil activation might be beneficial as an adjuvant therapy to thrombolysis in this setting.
Highlights
Cerebro- and cardiovascular acute ischemic afflictions such as myocardial infarction and ischemic stroke benefit of early reperfusion to reduce organ damage
We previously demonstrated that incubation with recombinant tissue plasminogen activator (r-tPA) was able to induce the phosphorylation of Akt, and ERK1/2 kinases [7] and that the migration of neutrophils towards r-tPA depends on its binding to the lipoprotein receptor-related protein 1 (LRP-1) receptor
We previously showed that the circulating levels of neutrophil degranulation products (MMP-8, matrix metalloproteases (MMPs)-9, MPO and NE) peak in stroke patients receiving r-tPA during the first hour after drug administration [7]
Summary
Cerebro- and cardiovascular acute ischemic afflictions such as myocardial infarction and ischemic stroke benefit of early reperfusion to reduce organ damage. The late restoration of the blood flow in a previously ischemic tissue associates with a paradoxical exacerbation of inflammation and oxidative stress leading to cellular dysfunction and death, the so-called ischemia/reperfusion (I/R) injury [3] Beside their important roles in host defence against infectious agents, neutrophils have been implicated in the pathogenesis of different conditions characterized by sterile inflammation such as I/R injury [4,5]. The effect of r-tPA on neutrophil function remains only partially investigated, the receptors and pathways involved in such process have not been fully identified This information will be of utmost importance to counteract r-tPA-induced neutrophil activation potentially widening our interventional options in the setting of I/R injury and ischemic stroke. We characterized the membrane receptor and the intracellular pathways underlying the observed effect
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
