Abstract Details

Title Histone Deacetylase 3 Inhibition Decreases Cerebral Edema and Protects the Blood-Brain Barrier after Stroke

Topic Cerebrovascular Disease and Interventional Neurology

Presentation(s) S33 - Cerebrovascular Disease: Basic Sciences and Cohort Studies (3:30 PM-3:42 PM)

Poster/Presentation
Number 001

Background HDAC3 is the most highly expressed class I HDAC in the brain. We have previously shown that selective HDAC3 inhibition decreases infarct volume and improves long-term neurologic outcomes after stroke.

Objective

To examine the effects of selective inhibition of histone deacetylase 3 (HDAC3) on cerebral edema and blood-brain barrier (BBB) leakage after stroke and explore its underlying mechanisms.

Design/Methods Adult male Wistar rats (n=6/group) were subjected to 2-h middle cerebral artery occlusion (MCAO) and randomly treated i.p. with either vehicle or a selective HDAC3 inhibitor (RGFP966) at 2 and 24 hours after stroke. Neurological severity scores (NSS) were calculated at 2 hours, 1 day, and 3 days. H&E and Evans blue dye (EBD) assay were employed to assess cerebral edema and BBB leakage, respectively. Western Blot for matrix metalloproteinase-9 (MMP9) and immunostaining for HDAC3, GFAP, Iba-1, albumin, aquaporin-4, claudin-5, ZO-1, and NF-kappa were also performed.

Results HDAC3 was upregulated in the peri-infarct cortex as early as 3 hours and up to 7 days after MCAO and significantly correlated with higher NSS (r=0.63, p=0.02). Early RGFP966 administration decreased cerebral edema (p=0.002) and BBB leakage, as measured by EBD assay and albumin extravasation (p=0.001). RGFP966 significantly increased the expression of tight junction proteins (claudin-5 and ZO-1) in the peri-infarct area. RGFP966 also significantly decreased HDAC3 expression in GFAP+ astrocytes, which correlated with better NSS (r=0.67, p=0.03) and decreased cerebral edema (r=0.64, p=0.04). RGFP966 decreased the expression of aquaporin-4 in GFAP+ astrocytes (p=0.002), as well as, the inflammatory markers Iba-1, NF-kappa, and MMP9 in the ischemic brain (p<0.05).

Conclusions Selective HDAC3 inhibition decreases cerebral edema and BBB leakage. BBB protection is mediated in part by upregulation of tight junction proteins, downregulation of aquaporin-4 and HDAC3 in astrocytes, and decreased neuroinflammation. Our findings suggest that targeting HDAC3 is a promising therapeutic approach for cerebral edema after malignant stroke.

Authors/Disclosures
Amjad Shehadah, MD (U.S. Food and Drug Administration) PRESENTER	Dr. Shehadah has nothing to disclose.
	No disclosure on file
	No disclosure on file
	No disclosure on file
	No disclosure on file
Marc Fisher, MD, FAAN (Beth Israel Deaconess Medical Center)	Dr. Fisher has received personal compensation in the range of $500-$4,999 for serving as a Consultant for AstraZeneca. Dr. Fisher has received personal compensation in the range of $10,000-$49,999 for serving as a Consultant for SimcereUSA. Dr. Fisher has received personal compensation in the range of $10,000-$49,999 for serving on a Scientific Advisory or Data Safety Monitoring board for SimcereUSA. Dr. Fisher has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for NoNo. Dr. Fisher has received personal compensation in the range of $100,000-$499,999 for serving as an Editor, Associate Editor, or Editorial Advisory Board Member for American Heart Association.
Eng Lo, MD (Massachusetts General Hospital)	No disclosure on file
Magdy H. Selim, MD, PhD (Beth Israel Deaconess Med. Ctr.)	Dr. Selim has received personal compensation in the range of $500-$4,999 for serving as a Consultant for MedRhythms Inc..