Rab7a activation promotes degradation of select tight junction proteins at the blood-brain barrier after ischemic stroke

Azzurra Cottarelli; Sanjid Shahriar; Ahmet Arac; Michael Glendinning; Mary Claire Tuohy; Grace Prochilo; Jason B Neal; Aimee L Edinger; Dritan Agalliu

doi:10.1101/2023.08.29.555373

Rab7a activation promotes degradation of select tight junction proteins at the blood-brain barrier after ischemic stroke

bioRxiv [Preprint]. 2023 Aug 30:2023.08.29.555373. doi: 10.1101/2023.08.29.555373.

Authors

Azzurra Cottarelli^{1

2}, Sanjid Shahriar^{2

3}, Ahmet Arac⁴, Michael Glendinning¹, Mary Claire Tuohy¹, Grace Prochilo¹, Jason B Neal^{1

5}, Aimee L Edinger⁶, Dritan Agalliu^{1

2}

Affiliations

¹ Departments of Neurology, Columbia University Irving Medical Center, New York, NY, 10032, USA.
² Departments of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, NY, 10032, USA.
³ Wyss Institute for Biologically Inspired Engineering, Boston, MA 02115, USA.
⁴ Department of Neurology, David Geffen School of Medicine, University of California in Los Angeles, Los Angeles, CA, 90095, USA.
⁵ Baylor Scott and White Health, Dallas, TX, 75226, USA.
⁶ Departments of Developmental and Cell Biology and Pharmaceutical Sciences, University of California, Irvine, CA 92697, USA.

Abstract

The stability of tight junctions (TJs) between endothelial cells (ECs) is essential to maintain blood-brain barrier (BBB) function in the healthy brain. Following ischemic stroke, TJ strand dismantlement due to protein degradation leads to BBB dysfunction, yet the mechanisms driving this process are poorly understood. Here, we show that endothelial-specific ablation of Rab7a, a small GTPase that regulates endolysosomal protein degradation, reduces stroke-induced TJ strand disassembly resulting in decreased paracellular BBB permeability and improved neuronal outcomes. Two pro-inflammatory cytokines, TNFα and IL1β, but not glucose and oxygen deprivation, induce Rab7a activation via Ccz1 in brain ECs in vitro, leading to increased TJ protein degradation and impaired paracellular barrier function. Silencing Rab7a in brain ECs in vitro reduces cytokine-driven endothelial barrier dysfunction by suppressing degradation of a key BBB TJ protein, Claudin-5. Thus, Rab7a activation by inflammatory cytokines promotes degradation of select TJ proteins leading to BBB dysfunction after ischemic stroke.

Keywords: Claudin-5; Rab7a; blood-brain barrier; cytokines; inflammation; ischemic stroke; tight junctions.

Publication types

Preprint

Abstract

Publication types

Grants and funding