Endothelium-targeted overexpression of heat shock protein 27 ameliorates blood-brain barrier disruption after ischemic brain injury.
Yejie ShiXiaoyan JiangLili ZhangHongjian PuXiaoming HuWenting ZhangWei CaiYanqin GaoRehana K LeakRichard F KeepMichael V L BennettJun ChenPublished in: Proceedings of the National Academy of Sciences of the United States of America (2017)
The damage borne by the endothelial cells (ECs) forming the blood-brain barrier (BBB) during ischemic stroke and other neurological conditions disrupts the structure and function of the neurovascular unit and contributes to poor patient outcomes. We recently reported that structural aberrations in brain microvascular ECs-namely, uncontrolled actin polymerization and subsequent disassembly of junctional proteins, are a possible cause of the early onset BBB breach that arises within 30-60 min of reperfusion after transient focal ischemia. Here, we investigated the role of heat shock protein 27 (HSP27) as a direct inhibitor of actin polymerization and protectant against BBB disruption after ischemia/reperfusion (I/R). Using in vivo and in vitro models, we found that targeted overexpression of HSP27 specifically within ECs-but not within neurons-ameliorated BBB impairment 1-24 h after I/R. Mechanistically, HSP27 suppressed I/R-induced aberrant actin polymerization, stress fiber formation, and junctional protein translocation in brain microvascular ECs, independent of its protective actions against cell death. By preserving BBB integrity after I/R, EC-targeted HSP27 overexpression attenuated the infiltration of potentially destructive neutrophils and macrophages into brain parenchyma, thereby improving long-term stroke outcome. Notably, early poststroke administration of HSP27 attached to a cell-penetrating transduction domain (TAT-HSP27) rapidly elevated HSP27 levels in brain microvessels and ameliorated I/R-induced BBB disruption and subsequent neurological deficits. Thus, the present study demonstrates that HSP27 can function at the EC level to preserve BBB integrity after I/R brain injury. HSP27 may be a therapeutic agent for ischemic stroke and other neurological conditions involving BBB breakdown.
Keyphrases
- heat shock protein
- blood brain barrier
- cerebral ischemia
- brain injury
- heat shock
- subarachnoid hemorrhage
- early onset
- cell death
- endothelial cells
- high glucose
- heat stress
- atrial fibrillation
- traumatic brain injury
- transcription factor
- nitric oxide
- late onset
- dna methylation
- acute myocardial infarction
- bone marrow
- white matter
- resting state
- gene expression
- small molecule
- drug delivery
- signaling pathway
- cell therapy
- vascular endothelial growth factor
- single cell
- multiple sclerosis
- copy number
- high speed
- mouse model