Substance P reversibly compromises the integrity and function of blood-brain barrier

Gao, Xin; Bayraktutan, Ulvi

Abstract

Background
Substance P (SP) plays a role in vasodilatation and tissue integrity through its receptor, neurokinin 1 (NK1R). However, its specific effect on blood-brain barrier (BBB) remains unknown.

Methods
The impact of SP on the integrity/function of human BBB model in vitro, composed of brain microvascular endothelial cells (BMECs), astrocytes and pericytes, was assessed by measurements of transendothelial electrical resistance and paracellular flux of sodium fluorescein (NaF), respectively in the absence/presence of specific inhibitors targeting NK1R (CP96345), Rho-associated protein kinase (ROCK; Y27632) and nitric oxide synthase (NOS; N(G)-nitro-L-arginine methyl ester). Sodium nitroprusside (SNP), a NO donor, was employed as a positive control. The levels of tight junction proteins, zonula occludens-1, occludin and claudin-5 alongside RhoA/ROCK/myosin regulatory light chain-2 (MLC2) and extracellular signal‑regulated protein kinase (Erk1/2) proteins were detected by western analyses. Subcellular localisations of F-actin and tight junction proteins were visualized by immunocytochemistry. Flow cytometry was used to detect transient calcium release.

Results
Exposure to SP increased RhoA, ROCK2 and phosphorylated serine-19 MLC2 protein levels and Erk1/2 phosphorylation in BMECs which were abolished by CP96345. These increases were independent of the changes in intracellular calcium availability. SP perturbed BBB in a time-dependent fashion through induction of stress fibres. Changes in tight junction protein dissolution or relocalisation were not involved in SP-mediated BBB breakdown. Inhibition of NOS, ROCK and NK1R mitigated the effect of SP on BBB characteristics and stress fibre formation.

Conclusion
SP promoted a reversible decline in BBB integrity independent of tight junction proteins expression or localisation.

Citation

Gao, X., & Bayraktutan, U. (2023). Substance P reversibly compromises the integrity and function of blood-brain barrier. Peptides, 167, Article 171048. https://doi.org/10.1016/j.peptides.2023.171048

• Journal Article Type: Article
• Acceptance Date: Jun 26, 2023
• Online Publication Date: Jun 28, 2023
• Publication Date: 2023-09
• Deposit Date: Jul 3, 2023
• Publicly Available Date: Jun 29, 2024
• Journal: Peptides
• Print ISSN: 0196-9781
• Electronic ISSN: 1873-5169
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 167
• Article Number: 171048
• DOI: https://doi.org/10.1016/j.peptides.2023.171048
• Keywords: Substance P Brain microvascular endothelial cells; Blood-brain barrier; RhoA Tight junctions; Neurokinin 1 receptor; Stress fibres
• Public URL: https://nottingham-repository.worktribe.com/output/22657156
• Publisher URL: https://www.sciencedirect.com/science/article/pii/S0196978123001110?via%3Dihub
• Additional Information: This article is maintained by: Elsevier; Article Title: Substance P reversibly compromises the integrity and function of blood-brain barrier; Journal Title: Peptides; CrossRef DOI link to publisher maintained version: https://doi.org/10.1016/j.peptides.2023.171048; Content Type: article; Copyright: © 2023 Elsevier Inc. All rights reserved.