Utilizing Ultrasound to Transiently Increase Blood-Brain Barrier Permeability, Modulate of the Tight Junction Proteins, and Alter Cytoskeletal Structure

Abstract

The central nervous system is protected by the blood-brain barrier (BBB). The tight junction (TJ) proteins claudin-5 and zonula occludens-1 (ZO-1) as well as the cytoskeletal component F-actin play key roles in maintaining homeostasis of the BBB. Increases in BBB permeability may be beneficial for the delivery of pharmacological substances into the brain. Therefore, here, we assessed the use of ultrasound to induce transient enhancement of BBB permeability. We used fluorescein isothiocyanate (FITC)-dextran 40 to detect changes in the membrane permeability of bEnd.3 cells during ultrasound treatment. Ultrasound increased FITC-dextran 40 uptake into bEnd.3 cells for 2-6 h after treatment; however, normal levels returned after 24 h. An insignificant increase in lactate dehydrogenase (LDH) leakage also occurred 3 and 6 h after ultrasound treatment, whereas at 24 h, LDH leakage was indistinguishable between the control and treatment groups. Expression of claudin-5, ZO-1, and F-actin at the messenger RNA (mRNA) and protein levels was assessed with real-time polymerase chain reaction and western blotting. Ultrasound induced a transient decrease in claudin-5 mRNA and protein expression within 2 h of treatment; however, no significant changes in ZO-1 and F-actin expression were observed. Claudin-5, ZO-1, and F-actin immunofluorescence demonstrated that the cellular structures incorporating these proteins were transiently impaired by ultrasound. In conclusion, our ultrasound technique can temporarily increase BBB permeability without cytotoxicity to exposed cells, and the method can be exploited in the delivery of drugs to the brain with minimal damage.

Restraint Stress Induced Hyperpermeability and Damage of the Blood-Brain Barrier in the Amygdala of Adult Rats

“…Occludin, claudin-5 and ZO-1 are the three most important TJ proteins. Down-regulation of TJ proteins can alter the cytoskeletal structure of BMVEC and induce an increase in BBB permeability (Bae et al, 2015). Decreased expression of TJ proteins has been considered an indicator of BBB structural damage (Kuan et al, 2016; Wang et al, 2016).…”

Limb remote ischaemic postconditioning‐induced elevation of fibulin‐5 confers neuroprotection to rats with cerebral ischaemia/reperfusion injury: Activation of the AKT pathway

“…The BBB is damaged when cerebral I/R injury occurs and a large amount of water enters the brain tissue, causing brain oedema . TJ proteins, between brain endothelial cells, are the principal structural components of BBB, which have an important role in maintaining BBB permeability . Previous study showed that TJ disruption may cause BBB breakdown .…”

“…17 TJ proteins, between brain endothelial cells, are the principal structural components of BBB, which have an important role in maintaining BBB permeability. 18,19 Previous study showed that TJ disruption may cause BBB breakdown. 20,21 Claudin-5 and occludin are two important TJ proteins.…”

Sevoflurane protects rat brain endothelial barrier structure and function after hypoxia-reoxygenation injury

“…Particularly in brain injury, this early phase of brain edema formation involves an increase of vascular endothelial growth factor (VEGF) [5], one of the most potent permeability factors [6] [7]. VEGF directly modifies endothelial cell junctions [8, 9] [10] as well as the actin cytoskeleton [11] and may therefore promote further disruption of the blood-brain barrier, finally leading to neuronal malfunction [12]. …”