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Inhibition of calcium/calmodulin‐dependent protein kinase kinase (Ca MKK ) exacerbates impairment of endothelial cell and blood–brain barrier after stroke
Author(s) -
Sun Ping,
Bu Fan,
Min JiaWei,
Munshi Yashasvee,
Howe Matthew D.,
Liu Lin,
Koellhoffer Edward C.,
Qi Li,
McCullough Louise D.,
Li Jun
Publication year - 2019
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1111/ejn.14223
Subject(s) - blood–brain barrier , endothelial stem cell , gene knockdown , protein kinase a , calcium in biology , viability assay , kinase , medicine , microbiology and biotechnology , pharmacology , chemistry , biology , apoptosis , endocrinology , intracellular , biochemistry , in vitro , central nervous system
Brain microvascular endothelial cells play an essential role in maintaining blood–brain barrier ( BBB ) integrity, and disruption of the BBB aggravates the ischemic injury. Ca MKK (α and β) is a major kinase activated by elevated intracellular calcium. Previously, we demonstrated that inhibition of Ca MKK exacerbated outcomes, conversely, overexpression reduced brain injury after stroke in mice. Interestingly, Ca MKK has been shown to activate a key endothelial protector, sirtuin 1 ( SIRT 1). We hypothesized that Ca MKK protects brain endothelial cells via SIRT 1 activation after stroke. In this study, Oxygen‐Glucose Deprivation ( OGD ) was performed in human brain microvascular endothelial cells. Stroke was induced by middle cerebral artery occlusion ( MCAO ) in male mice. Knockdown of Ca MKK β using si RNA increased cell death following OGD . Inhibition of Ca MKK β by STO ‐609 significantly and selectively down‐regulated levels of phosphorylated SIRT 1 after OGD . Changes in the downstream targets of SIRT 1 were observed following STO ‐609 treatment. The effect of STO ‐609 on cell viability after OGD was absent, when SIRT 1 was concurrently inhibited. We also demonstrated that STO ‐609 increased endothelial expression of the pro‐inflammatory proteins ICAM ‐1 and VCAM ‐1 and inhibition of Ca MKK exacerbated OGD ‐induced leukocyte‐endothelial adhesion. Finally, intracerebroventricular injection of STO ‐609 exacerbated endothelial apoptosis and reduced BBB integrity after 24‐hr reperfusion following MCAO in vivo. Collectively, these results demonstrated that Ca MKK inhibition reduced endothelial cell viability, exacerbated inflammatory responses and aggravated BBB impairment after ischemia. Ca MKK activation may attenuate ischemic brain injury via protection of the microvascular system and a reduction in the infiltration of pro‐inflammatory factors.