Title : P-selectin targeted nanocarriers are efficient drug delivery systems to activated endothelium
Inflammation is a common process associated with numerous vascular pathologies. During the vascular inflammation process, endothelial cells (EC) express both the receptors for advanced glycation end products (RAGE) and the cell adhesion molecule P-selectin that initiate and perpetuate inflammation by promoting leukocyte infiltration into the vascular wall. We questioned whether P-selectin could be employed as a target for nanotherapeutic intervention. We hypothesized that targeting the inflamed endothelium by coupling a peptide with high affinity for P-selectin to the surface of nanocarriers entrapping anti-inflammatory agents will highly increase their specific binding to activated EC and reduce the cell activation. Therefore, our aim was to develop suitable nanocarriers to perform specific and effective delivery of therapeutic agents to dysfunctional EC. We developed and characterized lipid-based nanoparticles directed towards P-selectin and used them as vectors for specific delivery of dexamethasone or small interfering (si) RNA/short hairpin (sh) RNA for RAGE and monitored their anti-inflammatory effects in vitro using cultured endothelial cells and in vivo using mouse models. Our results showed that nanocarriers directed to P-selectin bind specifically to activated endothelium and are functional in delivering the cargo (dexamethasone and RAGE-siRNA/shRNA) to EC, reducing the expression of proinflammatory genes and preventing the monocyte adhesion and transmigration to/through activated EC. The distribution of P-selectin targeted nanocarriers in different organs was assessed by an IVIS Imaging System at 1 hour after intravenous (i.v.) injection of fluorescently-labelled nanocarriers into a mouse model of acute inflammation (lipopolysaccharides (LPS) i.v. administered in C57BL/6 mice) and ApoE-deficient mice. Given i.v. in mice with acute inflammation, dexamethasone-loaded lipid nanoemulsions directed towards P-selectin accumulated at a significant high level in the lungs (compared to nontargeted nanoemulsions) and significantly reduced mRNA expression level of key proinflammatory cytokines such as IL-1????, IL-6, and MCP-1. To silence the expression of RAGE, a mixture of five plasmids that contain different RAGE-shRNA sequences was used to obtain lipoplexes with P-selectin targeted cationic liposomes (Psel-lipo/RAGE-shRNA) that were i.v. injected 2 times/week for 4 weeks in ApoE-deficient mice. The treatment with Psel-lipo/RAGE-shRNA specifically downregulated RAGE in the aorta and liver of mice and did not significantly alter the weight and the liver and kidney function. In conclusion, nanocarriers directed to P-selectin are efficient vectors for delivery of various therapeutic agents to activated endothelium. Acknowledgments. The work was supported by UEFISCDI, 13PCCDI/ 2018 (INTERA) and PN II-RU-TE-2014-4-1837 (NANORAGE) projects.
Audience take away:
• Vascular endothelium is an ideal target for therapeutic interference in chronic inflammation
• P-selectin is an appropriate target for nanotherapy
• Design of targeted lipid-based nanoparticles to carry small molecules or nucleic acids to vascular endothelium