Take advantage of the PbA-mouse model and an isolated perfused lung system to determine the role that CD36 interactions play in the changes to pulmonary vascular permeability observed during malaria infection. We found that PbA-infected CD362/2 mice were protected from the changes in fluid conductance observed in WT animals. Employing mouse lung microvascular endothelial cell cultures, it was determined that CD362/2 endothelial cells were also protected from reactive oxygen species -induced changes in barrier integrity. In addition, Fyn, a CD36-associated tyrosine kinase, was shown to exhibit an altered intracellular distribution and activation status in CD362/2 LMVECs and to be critical for (+)-JQ1 1268524-70-4 CD36-mediated increases in pulmonary endothelial cell fluid conductance during malaria. Our results suggest that CD36 signaling through Fyn tyrosine kinase plays a significant role in mediating the detrimental changes in pulmonary endothelial barrier function during malaria infection. In addition, the data point to the possibility that parasite- or hostderived ROS serve to enhance the CD36-mediated increases in paracellular fluid conductance during malaria. These findings suggest that targeting of the CD36-iRBC interaction in the lungs of patients at risk for pulmonary complications could reduce the severity of malaria-associated acute lung injury. The observed CD36-associated effects on capillary endothelial barrier integrity could result from multiple mechanisms. Interaction with the iRBC may induce CD36-mediated signal transduction events in vascular endothelial cells that cause alterations in permeability. It is also possible that the tethered iRBC is a direct or indirect source of factors that enhance the hyperpermeabilty phenotype. For example, ROS are known to increase pulmonary microvascular permeability. ROS production has been associated with P. falciparum asexual development and implicated in the pulmonary pathology associated with severe malarial. ROS can also be derived from resident or recruited mononuclear cells as they clear iRBCs from the lungs. Here we investigated the possibility that PbAinfected RBCs were a source of ROS. It is well established that during severe malaria infection in humans, parasite-containing erythrocytes adhere to pulmonary 
capillary endothelium and that this SAR131675 1433953-83-3 sequestration is associated with ARDS in up to 25% of adults. P. flacipariuminfected RBCs appear to use distributive interactions with CD36, ICAM1, PCAM-1 and chondroitin sulfate A to adhere to vascular endothelial cells. In murine models of human malaria, CD36 on vascular endothelial cells is the major binding partner for iRBCs. The high level of CD36 expression in the lungs results in the sequestration of large numbers of iRBCs with an attendant development of pulmonary inflammation and injury. A prominent feature of the lung pathology in humans and mice is pulmonary edema, suggesting that CD36-iRBC interactions could contribute directly or indirectly to alterations in endothelial cell barrier integrity. The results reported here support a mechanism in which iRBC interactions with CD36 initiates Fynmediated signaling that leads to an alteration in endothelial cell barrier function and pulmonary edema. In addition, our data identify parasite- or host-derived ROS as a possible contributor to this response. P. berghei infection in WT animals resulted in.10-fold increase in paracellular fluid conductance and a marked decrease in the reflection coefficient indicating failure of the endothelial mechanisms that exclude water and plasma proteins from the lungs. In striking contrast, the lungs of malaria-infected CD362/2 animals demonstrated significantly decreased water conductance when compared to WT mice, consistent with the observed lack of histological evidence of pulmonary edema after malaria challenge.