Asiaticoside Alleviates Alzheimer's Disease by Regulating PPP1CC Expression to Suppress Inflammation and Mitochondrial Dysfunction.

Abstract

<p>OBJECTIVE: Alzheimer's disease (AD) is a neurodegenerative disorder. Asiaticoside (AS), one of the main active components of Centella asiatica, shows therapeutic potential in various diseases, including AD. However, the specific molecular mechanisms by which AS treats AD remain unclear. METHODS: Cell counting kit-8 (CCK-8) and flow cytometry were used to assess cell viability, apoptosis, and changes in JC-1 mitochondrial membrane potential. Western blot (WB) was used to detect protein expression. The ferrous ion fluorescence assay kit was used to measure Fe2+ levels. Enzyme-linked immunosorbent assay (ELISA) kits were used to detect interleukin-1β (IL-1β) and IL-6 levels. GeneCards, comparative toxicogenomics database (CTD), and swisstargetprediction databases were used to obtain AD and AS targets. Enrichment analysis and plotting were performed using the clusterProfiler package in R. The simplified molecular input line entry system (SMILES) website was used to obtain the 3D structure of AS. The universal protein resource (UniProt) website was used to obtain the protein structure of protein phosphatase 1 catalytic subunit gamma (PPP1CC). Autodock v4.2.6 was used for molecular docking. RESULTS: AS improved cell viability in amyloid β1-42 (Aβ1-42)-induced human brain microvascular endothelial cells (HBMECs), reduced apoptosis, reduced Fe2+, IL-1β, and IL-6 levels, restored the JC-1 mitochondrial membrane potential, and increased the expression of glutathione peroxidase 4 (GPX4) and solute carrier family 7 member 11 (SLC7A11). Analysis identified six overlapping genes between AS and AD. Gene ontology (GO) functional annotation of these genes showed significant enrichment in response to hypoxia, neuron differentiation, and mitochondrial function. Kyoto encyclopedia of genes and genomes (KEGG) enrichment analysis revealed significant enrichment in tumor necrosis factor (TNF) signaling pathway, IL-17 signaling pathway, and others. Molecular docking demonstrated that AS could stably bind to the PPP1CC protein. Further experiments showed that PPP1CC knockdown exerted regulatory effects on Aβ1-42-induced HBMECs similar to those exerted by AS, whereas PPP1CC overexpression produced the opposite effects. CONCLUSION: AS protects Aβ1-42-induced HBMECs, likely through modulating PPP1CC expression.</p>