Plasmin in Parasitic Chronic Infections: Friend or Foe?. Issue 4 (April 2016) - González-Miguel, Javier
Abstract : Plasmin is the final product of the fibrinolytic system, the physiological mechanism responsible for dissolving fibrin clots. Its broad-range proteolytic activity implies that interaction with fibrinolysis and recruitment of plasmin by blood and tissue parasites is an important mechanism that mediates the invasion and establishment of this kind of pathogen in the hosts. However, recent studies have linked an excess of plasmin generated by this interaction with serious pathological events at the vascular level, including the proliferation and migration of arterial wall cells, inflammation, and degradation of the extracellular matrix. Therefore, we present data that support the need to reconsider the role of plasmin, as well as its benefits or drawbacks, in the context of host–parasite relations. Trends: Plasmin is the product of the activation of plasminogen, a key enzyme of the fibrinolytic system. As a broad-spectrum serine protease, plasmin exerts its proteolytic function on not only fibrin clots, but also a variety of substrates, including some components of the extracellular matrix. A large number of blood and tissue parasites interact with the fibrinolytic system of their hosts by the expression and secretion of plasminogen receptors, which have been linked to parasite survival mechanisms. The indiscriminate proteolytic activity of plasmin has been recently related to cardiovascular disease and important pathological mechanisms, such as cell proliferation and migration and inflammation in blood vessels. Here, we review the use of the fibrinolytic system by parasites and its consequences for their survival and pathology.