Withanolide A is a naturally occurring phytochemical that is found in Ashwagandha (Withania somnifera, fam. Solanaceae) or Indian Ginseng. In the current study, we elucidated the effect of withanolide A on 7-ketocholesterol (7KC) induced injury in hCMEC/D3 human brain endothelial cells. 7KC is a cholesterol oxidation product or oxysterol that is present in atherosclerotic plaques and is elevated in the plasma of patients with hypercholesterolemia and/or diabetes mellitus. Results showed that withanolide A significantly reduced the effects of 7KC, which include loss of endothelial cell viability, increase in expression of pro-inflammatory genes-IL-1β, IL-6, IL-8, TNF-α, cyclooxygenase-2 (COX-2), increased COX-2 enzyme activity, increased ROS formation, increased expression of inducible nitric oxide synthase and genes associated with blood clotting, including Factor 2/thrombin, Factor 8, von Willebrand factor, and thromboxane A synthase, and increased human thrombin enzyme activity. Some of the above effects of withanolide A on 7KC were reduced in the presence of the glucocorticoid receptor antagonist, mifepristone (RU486). These findings suggest that the glucocorticoid receptor could play a role in the cytoprotective, antioxidant, and anti-clotting effects of withanolide A against 7KC. Further studies are necessary to elucidate the detailed mechanisms of action of withanolide A against oxysterol-induced injury.
Keywords: withanolide A, 7-ketocholesterol, brain endothelial cells, blood-brain-barrier, hypercholesterolemia, diabetes mellitus, vascular dementia, cerebral ischemia
Author Biography
Wei-Yi Ong, Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119260, Singapore; [email protected]
Neurobiology Research Programme, Life Sciences Institute, National University of Singapore, Singapore 119260, Singapore
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