A novel S1P analogue/MLCK inhibitory peptide-encargoed nanocarrier to attenuate lung vascular leak

Unremitting increases in lung vascular permeability is the pathophysiological hallmark of acute lung injuries (ALI) and drives both severity and mortality. Therapies with the capacity to quickly restore vascular integrity in ALI remains a serious unmet need. Our laboratory was first to report both the vascular barrier-protective effects of sphingosine-1 -phosphate (S1P) and S1P analogues, such as Tysiponate (TySIP), and the efficacy of peptide inhibitors (PIK) of non-muscle myosin light chain kinase (nmMLCK) as dual complementary strategies to reduce vascular permeability. The current study evaluates a novel nanocarrier (NTyP-100) containing conjugated TySIP and encargoed PIK as a pharmacologic approach to vascular barrier restoration in rodent models of LPS-induced ALI. NTyP-100 (or controls) was delivered IV to wild-type C57BL/6J mice exposed to a "one-hit" lipopolysaccharide (LPS, 18 h) ALI model or to Sprague-Dawley (SD) rats challenged by a "two-hit" ALI model combining LPS (18 h) and exposure to high tidal volume mechanical ventilation (MV, 4 h). Compared to TySIP or PIK alone, IV NTyP-100 produced the highest reduction (∼40%) in inflammatory injury in murine and rat ALI models (H&E, IHC p-MLC staining, BAL cells) with marked reductions in vascular leak (Evan Blue Dye leakage, BAL protein) and biochemical indices of inflammation. Genomic studies underscored NTyP-100 attenuation of ALI-mediated dysregulated barrier-regulatory signaling pathways (inflammatory response, innate immunity, TNF, IL-17, apoptosis). These studies demonstrate the successful therapeutic targeting of vascular barrier properties and supports the NTyP-100 nanocarrier as a strategy to address the unmet need for novel therapeutics that mitigate inflammatory injury and vascular permeability.