Celastrol Enhances Cell Viability and Inhibits Amyloid-β Production Induced by Lipopolysaccharide In Vitro

Abstract

Background:

Neuroinflammation is a notable hallmark of Alzheimer’s disease pathogenesis and can markedly exacerbate amyloid pathology. Celastrol, a pentacyclic-triterpene, has been found to possess anti-inflammatory properties.

Objective:

The purpose of this study was to characterize the effects of celastrol on cell viability and amyloid-β (Aβ) peptide production induced by lipopolysaccharide (LPS) administration in H4 human neuroglioma cells stably transfected to overexpress human full length APP (H4-APP).

Methods:

H4-APP cells were exposed to 1, 10, and 100 nM of celastrol in the presence of 0.1 µg/ml or 100 µg/ml of LPS for 24 hours. The effects of celastrol were determined using MTT cell viability assay, immunohistochemistry, western blot, and ELISA.

Results:

Cell viability tests revealed that a dose-dependent death of H4-APP cells following administration of LPS. Moreover, celastrol significantly reduced (p < 0.05) cell death induced by LPS compared to LPS alone. Furthermore, the administration of celastrol was associated with a significant reduction in LPS-stimulated Aβ production compared to LPS alone. Western blot and immunofluorescence analysis showed that exposure to celastrol increased HSP-70 and Bcl-2 expression but decreased NFκB activity, phosphorylated glycogen synthase kinase-3β (GSK-3β) at tyrosine 216 and cyclooxygenase-2 (COX-2) expression, Aβ accumulation together with a reduction of superoxide and hydrogen peroxide generation. HSP-70 siRNA abolished celastrol mediated cytoprotection.

Conclusion:

This study demonstrates that celastrol reduced both LPS-induced cell death and Aβ production in vitro through increasing HSP-70 and Bcl-2 expression and reducing NFκB, COX-2, and GSK-3β expression and oxidative stress.