The formation of a blood clot (thrombus) in the circulatory system is the body mechanism to repair an injured blood vessel, but if a thrombus is formed when it is not needed, that leads to severe medical conditions, such as embolism, ischemia, heart-attack and stroke. In order to solve this problem, several thrombolytic therapies are being study, namely therapies that use enzymes.
The current therapies pose serious drawbacks, like very short half-lives in plasma, as a consequence of unspecific uptake and clearance by the mononuclear phagocytic system, and due to cleavage by endogenous proteases. Additionally, recombinant proteins and peptides are recognized by the immune system, which produces antibodies to neutralize their activity. Therefore, the development of new approaches for thrombolytic therapy is of the outmost importance.
In this sense, nanotechnology is an appealing avenue for the delivery of thrombolytic agents, as liposomes can reduce the therapeutic dosages, enable targeted delivery, improve stability in physiologic conditions and avoid immune recognition.
Hence, in this project we will pursue the development a thrombolytic therapy, by exploiting the interesting characteristics of a microbial enzyme expressed by a Bacillus subtilis S127e, isolated in Azores, that as shown a potent thrombolytic plasmin-like protease to thrombi. Additionally, to improve upon its therapeutic activity, the enzyme will be encapsulated in nanosized liposomes functionalized with one, or a combination of specific peptides, that will confer targeted delivery to thrombi.