A Protein Tyrosine Phosphatase 4A3 (PTP4A3) inhibitor prevents and repairs pulmonary endothelial barrier dysfunction and ameliorates acute lung injury provoked by the SARS‐CoV‐2 Spike protein subunit 1 in k18‐hACE2 transgenic mice

PTP4A3 regulates various inflammatory and cytoskeletal signaling pathways (e.g., STAT3, RhoA, ERK, AKT) that are involved in endothelial barrier dysfunction and acute lung injury (ALI). We have investigated the actions of JMS-053, a small PTP4A3 inhibitor, in both in vitro and in vivo models of SARS-CoV-2 Spike protein subunit 1 (S1SP)-induced endothelial inflammation and acute lung injury. S1SP (10nM) caused a time-dependent endothelial barrier dysfunction in human lung microvascular endothelial cell monolayers that was ameliorated by JMS-053 (12.5µM) administered either as pre-treatment (4 hours prior to S1SP) or post-treatment (5 hours after S1SP). In K18-hACE2 transgenic mice, which express the human ACE2 receptor for SARS-CoV-2 S1SP, we instilled S1SP intratracheally, post-treated with JMS-053 (10mg/kg i.p. at 1, 24 and 48 hours after S1SP) or vehicle, and investigated molecular, functional and histological outcomes 72 hours later. JMS-053 mice displayed lower alveolar cellularity, proteinosis and "cytokine storm" (i.e., IL-6, IL-1β, IL-17), and lower levels of phosphorylated (activated) STAT3 and NF-kB, compared to mice instilled with S1SP and treated with vehicle. Moreover, JMS-053 greatly reduced quantifiable histological evidence of injury, compared to vehicle-treated animals. This data suggests that inhibition of PTP4A3 could represent a critical target for novel therapeutic approaches towards endothelial dysfunction, inflammation and acute lung injury.