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Inhibition of HSP90 Preserves Blood-Brain Barrier Integrity after Cortical Spreading Depression Via Claudin 5 Upregulation

2022; RELX Group (Netherlands); Linguagem: Inglês

10.2139/ssrn.4004731

1556-5068

Seph M. Palomino, Aidan Levine, Jared Wahl, Erika Liktor‐Busa, John M. Streicher, Tally M. Largent‐Milnes,

Neonatal and fetal brain pathology

Cortical spreading depression (CSD) is a pathophysiological mechanism underlying headache disorders, including migraine. Blood-brain barrier (BBB) permeability is increased during CSD. Recent papers have suggested that heat-shock proteins (HSP) contribute to the integrity of the blood-brain barrier. In this study, the possible role of HSP90 in CSD-associated blood-brain barrier leak at the endothelial cell was investigated using an in vitro model, for the blood endothelial barrier (BEB), and an in vivo model with an intact BBB. We measured barrier integrity using trans endothelial electric resistance (TEER) across a monolayer of rodent brain endothelial cells (bEnd.3), a sucrose uptake assay, and in situ brain perfusion using female Sprague Dawley rats. CSD was induced by application of 60 mM KCl for 5 minutes in in vitro experiments or cortical injection of KCl (1M, 0.5 µL) through a dural canula in vivo. HSP90 was selectively blocked by 17-AAG. Our data showed that preincubation with 17-AAG (1µM) prevented the reduction of TEER values caused by KCl pulse on the monolayer of bEnd.3 cells. The elevated uptake of 14C-sucrose across the same endothelial monolayer induced by KCl pulse was significantly reduced after preincubation with HSP90 inhibitor. Pre-exposure to 17-AAG significantly mitigated the transient BBB leak after CSD induced by cortical KCl injection as determined by in situ brain perfusion in female rats. Our results demonstrated that inhibition of HSP90 with the selective agent 17-AAG reduced CSD-associated BEB/BBB paracellular leak. Overall, this novel observation supports the role of HSP90 in negatively regulating the integrity of the BBB and suggests the development of new therapeutic approaches targeting HSP90 in headache disorders.Funding Information: This work was supported by ABRC AHDS18-45952 (TML), NIH/NINDS R01NS099292 (TML), NIH/NIDA R01DA052340 (JMS), and ABRC ADHS18-198875 (JMS).Conflict of Interests: JMS has an equity stake in Botanical Results, LLC and is a co-founder of Teleport Pharmaceuticals, LLC. No company products or interests were tested in this study. The authors declare no other competing interests.Ethical Approval: All animal work presented in this paper was approved by the IACUC at the University of Arizona and followed recommendations of the International Association for the Study of Pain and the NIH guidelines for laboratory animals.