Doxycycline induces membrane expression of VE-cadherin on endothelial cells and prevents vascular hyperpermeability.
ABSTRACT The endothelium lining blood vessels serves as a barrier against vascular hyperpermeability, and its maintenance is critical to organ health. Inflammatory mediators evoke tissue edema by disrupting the expression of membrane junctional proteins, which mediate binding between endothelial cell membranes. Endothelial cell-cell junctions form a diffusion barrier between the intravascular and interstitial space. To prevent the morbidity and mortality caused by exaggerated vascular permeability associated with pathological states (e.g., inflammatory and hypersensitivity disorders, pulmonary edema, traumatic lung injury, cerebral edema resulting from stroke, and others), it is important to develop therapeutic approaches to stabilize these interendothelial junctions. Vascular endothelial growth factor (VEGF), a potent proangiogenic cytokine, was first described as vascular permeability factor (VPF). Doxycycline, a tetracycline derivative, has been shown to inhibit angiogenesis in both humans and animal models. We now report that oral doxycycline prevents VPF/VEGF-induced vascular permeability, interleukin-2-induced pulmonary edema, and delayed-type hypersensitivity (DTH) in mice. Remarkably, doxycycline also inhibits tumor growth and tumor-associated vascular hyperpermeability. Finally, we show that doxycycline targets the adherens junction in vascular endothelial cells by inducing the total amount of VE-cadherin expression while decreasing the degree of its phosphorylation. The potential of doxycyline as a therapeutic inhibitor of vascular hyperpermeability in human clinical conditions is promising and warrants further studies.
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ABSTRACT: Leptospirosis is a widespread zoonotic infection that primarily affects residents of tropical regions, but causes infections in animals and humans in temperate regions as well. The agents of leptospirosis comprise several members of the genus Leptospira, which also includes non-pathogenic, saprophytic species. Leptospirosis can vary in severity from a mild, non-specific illness to severe disease that includes multi-organ failure and widespread endothelial damage and hemorrhage. To begin to investigate how pathogenic leptospires affect endothelial cells, we compared the responses of two endothelial cell lines to infection by pathogenic versus non-pathogenic leptospires. Microarray analyses suggested that pathogenic L. interrogans and non-pathogenic L. biflexa triggered changes in expression of genes whose products are involved in cellular architecture and interactions with the matrix, but that the changes were in opposite directions, with infection by L. biflexa primarily predicted to increase or maintain cell layer integrity, while L. interrogans lead primarily to changes predicted to disrupt cell layer integrity. Neither bacterial strain caused necrosis or apoptosis of the cells even after prolonged incubation. The pathogenic L. interrogans, however, did result in significant disruption of endothelial cell layers as assessed by microscopy and the ability of the bacteria to cross the cell layers. This disruption of endothelial layer integrity was abrogated by addition of the endothelial protective drug lisinopril at physiologically relevant concentrations. These results suggest that, through adhesion of L. interrogans to endothelial cells, the bacteria may disrupt endothelial barrier function, promoting dissemination of the bacteria and contributing to severe disease manifestations. In addition, supplementing antibiotic therapy with lisinopril or derivatives with endothelial protective activities may decrease the severity of leptospirosis.PLoS Neglected Tropical Diseases 01/2010; 4(12):e918. · 4.69 Impact Factor