Abstract TMP19: Atn-161 Prevents α5 Integrin-mediated Tight Junction Disruption Caused By Sars-cov-2 And Its Delta Variant In Brain Endothelial Cells

Patients with significant cerebrovascular comorbidities (e.g. brain ischemia, vascular dementia) are more affected and are more likely to have worsened post-acute neurologic sequelae after SARS-CoV-2 infection. This may be due to viral invasion and propagation in brain endothelial cells (BECs) and disruption of the blood-brain barrier (BBB). Viral spike protein used to bind and infect host cells encodes an arginine-glycine-aspartic acid (RGD) motif that it may use to bind integrins cell receptors that play an important role in cerebrovascular integrity. Therefore, integrins may represent an acute and post-acute SARS-CoV-2 therapeutic target. However, the interplay between vascular dysregulation, integrin function, and COVID-19 is unclear. As we have previously demonstrated that activation of the integrin α5 plays a key role in BBB breakdown, stroke injury, OGD/R, SARS-CoV-2 infection, and its inhibition with the clinically validated peptide ATN-161 is therapeutic in these conditions, we hypothesize that SARS-CoV-2 alters BEC α5 integrin (and associated tight junction protein) expression as a means of infecting and altering cerebrovascular integrity, and this can be prevented by ATN-161. Methods: Mouse BECs (bEnd3) were inoculated with heat-inactivated SARS-CoV-2 (Isolate USA-WA1/2020) or delta variant of SARS-CoV-2 spike protein for 24 h then later exposed to hypoxia for 6h to model the effects of in vivo pulmonary infection. Cells were pretreated with ATN-161 (1, 5, and 10μM) 1h before SARS-CoV-2 challenge and during hypoxia. α5 and claudin-5 proteins were analyzed by immunoblotting. Results: Both SARS-CoV-2 inoculations induced integrin α5 and decreased claudin-5 expression (delta > SARS-CoV-2) in a dose-dependent fashion, although higher doses of SARS-CoV-2 (2.5 and 5 μg) had no effect on these proteins. SARS-CoV-2 spike protein challenge at 0.5 μg followed by hypoxia resulted in increased α5 and decreased claudin-5 expression in either hypoxia or SARS-CoV-2+hypoxia combination. ATN-161 (10μM) pretreatment inhibited SARS-CoV-2+hypoxia-induced α5 upregulation and restored claudin-5 loss. In addition to its demonstrated anti-viral effects, ATN-161 may be an important therapy for SARS-CoV-2-mediated cerebrovascular injury.