Tanshinone IIA improves Alzheimer's disease via RNA nuclear-enriched abundant transcript 1/microRNA-291a-3p/member RAS oncogene family Rab22a axis.

Abstract

Alzheimer's disease (AD) is a neurodegenerative condition characterized by oxidative stress and neuroinflammation. Tanshinone IIA (Tan-IIA), a bioactive compound isolated from Salvia miltiorrhiza plants, has shown potential neuroprotective effects; however, the mechanisms underlying such a function remain unclear. To investigate potential Tan-IIA neuroprotective effects in AD and to elucidate their underlying mechanisms. Hematoxylin and eosin staining was utilized to analyze structural brain tissue morphology. To assess changes in oxidative stress and neuroinflammation, we performed enzyme-linked immunosorbent assay and western blotting. Additionally, the effect of Tan-IIA on AD cell models was evaluated in vitro using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Genetic changes related to the long non-coding RNA (lncRNA) nuclear-enriched abundant transcript 1 (NEAT1)/microRNA (miRNA, miR)-291a-3p/member RAS oncogene family Rab22a axis were assessed through reverse transcription quantitative polymerase chain reaction. In vivo, Tan-IIA treatment improved neuronal morphology and attenuated oxidative stress and neuroinflammation in the brain tissue of AD mice. In vitro experiments showed that Tan-IIA dose-dependently ameliorated the amyloid-beta 1-42-induced reduction of neural stem cell viability, apoptosis, oxidative stress, and neuroinflammation. In this process, the lncRNA NEAT1 - a potential therapeutic target - is highly expressed in AD mice and downregulated via Tan-IIA treatment. Mechanistically, NEAT1 promotes the transcription and translation of Rab22a via miR-291a-3p, which activates nuclear factor kappa-B (NF-κB) signaling, leading to activation of the pro-apoptotic B-cell lymphoma 2-associated X protein and inhibition of the anti-apoptotic B-cell lymphoma 2 protein, which exacerbates AD. Tan-IIA intervention effectively blocked this process by inhibiting the NEAT1/miR-291a-3p/Rab22a axis and NF-κB signaling. This study demonstrates that Tan-IIA exerts neuroprotective effects in AD by modulating the NEAT1/miR-291a-3p/Rab22a/NF-κB signaling pathway, serving as a foundation for the development of innovative approaches for AD therapy.