ABSTRACT: Acute respiratory distress syndrome (ARDS) is a severe pulmonary disease characterized by acute, noncardiogenic pulmonary edema and hypoxemia leading to respiratory failure with a diverse array of etiologies, including the recent SARS-CoV-2 infection. The current standard of care for ARDS remains predominantly supportive, underscoring the urgent need for targeted pharmacological interventions. To address this critical gap, we have developed an inhibitor to the microtubule accessory factor end binding protein 3 (EB3), a key mediator in the pathogenesis of ARDS. During injury, EB3 in endothelial cells facilitates the cluster of inositol 1,4,5-trisphosphate receptor 3 (IP3R3) clustering on the endoplasmic reticulum surface activating pathological calcium signaling. Building on our prior research, we have designed and optimized an EB3 inhibitor, termed Vascular Therapeutics (VT)-109, with enhanced physicochemical properties using NMR approaches. Recognizing the diverse etiologies of ARDS, we evaluated the therapeutic potential of VT-109 using a range of preclinical models, including PAR-1 agonist-, endotoxin-, polymicrobial sepsis-, mechanical ventilation-, SARS-CoV-2-induced models of ARDS in mice. Treatment of VT-109 protects the lungs of mice from vascular leakage caused by ARDS by upregulating VE-cadherin at the endothelial junctions. Molecularly, VT-109 reduces the inflammatory NFAT and NFκB pathways while simultaneously activating the endothelial regenerative FOXM1 pathway. Additionally, VT-109 mitigated ARDS-induced lung injury, reduced inflammatory cytokine production, decreased morbidity and mortality, and improved lung functions. Collectively, these data demonstrate that targeting EB3-mediated pathological calcium signaling within pulmonary endothelial cells with VT-109 could provide a promising therapeutic strategy for the treatment of ARDS.
