Cystatin C improves blood–brain barrier integrity after ischemic brain injury in mice

Abstract

Cystatin C, a well-established biomarker of renal function, has been associated with a protective effect against stroke. However, the potential neuroprotective mechanism of cystatin C in ischemic brain injury remains unclear. Our study hypothesized that cystatin C can ameliorate blood-brain barrier (BBB) disruption by up-regulating caveolin-1 expression, thereby improving neurological outcomes in cerebral ischemic injury. Western blotting, immunohistochemistry, immunofluorescence staining, and immunoprecipitation were performed to investigate target proteins. Evans Blue and gelatin zymography were used to examine the effect of cystatin C on BBB disruption. Plasmid and small interfering RNA transfection was used to observe alterations in caveolin-1 and occludin expression induced by changes in cystatin C expression. Intriguingly, our study showed that the expression of both cystatin C and caveolin-1 was increased in middle cerebral artery occlusion-injured mice, and pretreatment with exogenous cystatin C significantly increased caveolin-1 expression, reduced Evans Blue leakage in the injured brain region, and decreased the enzymatic activity of matrix metallopeptidase-9. Meanwhile, our study also showed that the over-expression of cystatin C greatly enhanced caveolin-1 expression, which later increased occludin expression in oxygen-glucose deprivation-exposed brain microvascular endothelial cells. The knockdown of cystatin C induced the opposite outcomes. These experimental results indicate a positive role for cystatin C in the regulation of caveolin-1 and occludin expression in cerebral ischemic injury. Taken together, these data unveil a new mechanism of the regulation of caveolin-1 expression by cystatin C in the maintenance of BBB integrity after ischemic brain injury and provide new clues for the identification of potential therapeutic strategies for stroke. Keywords: bEnd.3, blood-brain barrier, caveolin-1, cystatin C, ischemic brain injury, occludin. are co-first authors.Abbreviations used: BBB, blood-brain barrier; bEnd.3, brain microvascular endothelial; DMEM, Dulbecco's modified Eagle medium; I/R, ischemia/reperfusion; ICV, intracerebroventricular; MCAO, middle cerebral artery occlusion; MMP-9, matrix metallopeptidase-9; MMPs, matrix metalloproteinases; OGD, oxygen-glucose deprivation; PBS, phosphate buffered saline; SDS, sodium dodecyl sulfate; siRNA, small interfering RNA. | 2020 | 153 | 413-425 JOURNAL OF NEUROCHEMISTRY

Rosiglitazone Protects Blood-Brain Barrier Integrity Following Ischemic Stroke by Reducing MMP-9 Expression Through a Caveolin-1-Dependent Pathway

“…increased, suggesting that caveolin-1 might play a protective role by inhibiting the expression of MMP-9. The results of our study are similar to that of a recent research conducted by Yang et al [36], they showed that the expression of caveolin-1 was up-regulated in MCAO-injured mice, and pretreatment with cystatin C could further increased caveolin-1 and decreased the enzymatic activity of MMP-9. The up-regulation of caveolin-1 during ischemia may be a protective compensatory response to prevent brain damage.The positive correlation between caveolin-1 expression and functional de cit may be related to the compensatory increase of caveolin-1during ischemia.…”

Rosiglitazone Protects Blood-Brain Barrier Integrity Following Ischemic Stroke by Reducing MMP-9 Expression Through a Caveolin-1-Dependent Pathway.

“…The results of our study are similar to that of a recent research conducted by Yang et al [35], they showed that the expression of caveolin-1 was up-regulated in MCAO-injured mice, and pretreatment with cystatin C could further increased caveolin-1 and decreased the enzymatic activity of MMP-9. The up-regulation of caveolin-1 during ischemia may be a protective compensatory response to prevent brain damage.…”

Rosiglitazone Protects Blood-Brain Barrier Integrity Following Ischemic Stroke by Reducing MMP-9 Expression Through a Caveolin-1-Dependent Pathway

“…Moreover, after the administration of daidzein, the level of caveolin-1 decreased, while the level of MMP-9 increased, suggesting that caveolin-1 might play a protective role by inhibiting the expression of MMP-9. The results of our study are similar to that of a recent research conducted by Yang et al [40], they showed that the expression of caveolin-1 was up-regulated in MCAO-injured mice, and pretreatment with cystatin C could further increased caveolin-1 and decreased the enzymatic activity of MMP-9. The up-regulation of caveolin-1 during ischemia may be a protective compensatory response to prevent brain damage.…”