Exendin-4 Preserves Blood-Brain Barrier Integrity via Glucagon-Like Peptide 1 Receptor/Activated Protein Kinase-Dependent Nuclear Factor-Kappa B/Matrix Metalloproteinase-9 Inhibition After Subarachnoid Hemorrhage in Rat.

Zhiyi Xie,Tongyu Zhang,Jiping Tang,Matei Nathanael,Lingyun Wu,Budbazar Enkhjargal,Qiquan Zhu,John H. Zhang

doi:10.3389/fnmol.2021.750726

Abstract

In this study, we investigated the role of Exendin-4 (Ex-4), a glucagon-like peptide 1 receptor (GLP-1R) agonist, in blood-brain barrier (BBB) disruption after subarachnoid hemorrhage (SAH) in rats. The endovascular perforation model of SAH was performed in Sprague-Dawley rats. Ex-4 was intraperitoneally injected 1 h after SAH induction. To elucidate the underlying molecular mechanism, small interfering ribonucleic acid (siRNA) for GLP-1R and Dorsomorphin, a specific inhibitor of adenosine monophosphate-activated protein kinase (AMPK), were intracerebroventricularly injected 48 h before induction of SAH correspondingly. Immunofluorescence results supported GLP-1R expressed on the endothelial cells of microvessels in the brain after SAH. Administration of Ex-4 significantly reduced brain water content and Evans blue extravasation in both hemispheres, which improved neurological scores at 24 h after SAH. In the mechanism study, Ex-4 treatment significantly increased the expression of GLP-1R, p-AMPK, IκB-α, Occludin, and Claudin-5, while the expression of p-nuclear factor-kappa B (NF-κB) p65, matrix metalloproteinase-9 (MMP-9), and albumin was significantly decreased. The effects of Ex-4 were reversed by the intervention of GLP-1R siRNA or Dorsomorphin, respectively. In conclusion, Ex-4 could preserve the BBB integrity through GLP-1R/AMPK-dependent NF-κB/MMP-9 inhibition after SAH, which should be further investigated as a potential therapeutic target in SAH.

Highlights

Subarachnoid hemorrhage (SAH) is a feared disease with a high rate of mortality and disability
When we compared the subarachnoid hemorrhage (SAH) grading scores of all animals prepared for brain water content (BWC) measurement and western blots/gelatin zymography at 24 h after surgery, no significant difference was detected among the SAH groups (Figure 1C)
Double immunofluorescence of glucagon-like peptide 1 receptor (GLP-1R) and von Willebrand factor (vWF) was performed on the brain sample sections collected 24 h after SAH induction

Summary

Introduction

Subarachnoid hemorrhage (SAH) is a feared disease with a high rate of mortality and disability (van Gijn et al, 2007; Nieuwkamp et al, 2009). Brain injury (EBI) is considered a significant determinant of unfavorable outcomes following SAH (Sehba et al, 2012). Disruption of the blood-brain barrier (BBB) is a critical pathologic process of EBI and shows promise as a therapeutic target in ameliorating the detrimental effects of SAH (Chen et al, 2014). MMP-9 has been shown to cause BBB disruption through the degradation of basal lamina proteins, tight junctions, and the extracellular matrix (Guo et al, 2010; Ying et al, 2016). The regulation of NF-κB has therapeutic potential to downregulate MMP-9, prevent BBB disruption, and ameliorate the deleterious neurological damage of SAH

Methods

Results

Conclusion