Mechanisms of BBB dysfunction and repair after ischemic stroke

Dysregulated BBB permeability is a key feature of the pathology of ischemic stroke. We have previously shown that BBB disruption occurs in two distinct waves: an early phase driven by an increase in transcytosis (transcellular permeability), and a later phase due to endothelial junctions dismantling (paracellular permeability). While we can successful prevent the first wave by inhibiting transcellular transport in the animal model (Caveolin-1 knock-out), we are still investigating the molecular mechanisms that regulate paracellular permeability with the ultimate goal to rescue the second wave of BBB dysruption. In particular, we are focusing and the role of Rab7, a small GTPase involved in the endocytic pathway by potentially directing endothelial junctional proteins to lysosomal degradation after stroke.

We are also interested in understanding the impact that sensory stimulation has on BBB function after ischemic stroke. Sensory stimulation in animal models of ischemic stroke has been repeatedly shown to reduce the stroke volume and to ameliorate the neurological manifestations, supposedly by providing an emergency supply of blood flow through collateral circulation. However, the translation of sensory stimulation in the human pathology has proven to be ineffective, or even deleterious. Together with a network of other European and US laboratories, we are investigating the molecular mechanisms activated by sensory stimulation, particularly at the level of the BBB, with the aim of identifying a therapeutic protocol that would be safely translatable to the clinical setting.