Neuroprotective effects of SRS11-92 against oxidative stress-induced senescence via Nrf2/HO-1/NF-κB in Alzheimer's disease models.

Abstract

BACKGROUND: Oxidative stress, neuroinflammation, and cellular senescence interact to drive Alzheimer's disease (AD) progression. SRS11-92 is a redox-active small molecule with reported cytoprotective effects. This study sought to determine whether SRS11-92 mitigates Aβ-evoked oxidative stress and cellular senescence, and to delineate the underlying mechanism. METHODS: SH-SY5Y cells were challenged with Aβand pretreated with SRS11-92. Oxidative stress (ROS, MDA, SOD activity, and GSH), inflammatory mediators (TNF-α, IL-1β, and IL-6), senescence markers (SA-β-gal, p53, p16, and p21), and Nrf2/HO-1/NF-κB proteins were quantified. Pathway dependence was assessed using the selective Nrf2 inhibitor ML385. 3xTg-AD mice received SRS11-92 for 6 weeks; cognitive function was assessed by novel object recognition, cortical neuronal integrity was assessed by Nissl staining, and cellular senescence in the hippocampus was evaluated by SA-β-gal. RESULTS: SRS11-92 attenuated Aβ-induced cytotoxicity in a dose-dependent manner in SH-SY5Y cells, reduced ROS and MDA, and restored SOD activity and GSH. It suppressed TNF-α, IL-1β, and IL-6, decreased the percentage of SA-β-gal-positive cells, and downregulated p53, p16, and p21. Mechanistically, SRS11-92 increased total and nuclear Nrf2 and upregulated HO-1, while restricting NF-κB p65 nuclear translocation. ML385 abrogated these molecular and phenotypic benefits, confirming that SRS11-92 acts via the Nrf2 pathway in vitro. In 3xTg-AD mice, SRS11-92 improved cognitive function, partially rescued cortical Nissl-positive neurons, and reduced the hippocampal SA-β-gal-positive burden. CONCLUSIONS: SRS11-92 exerts significant neuroprotective effects, attributable to reducing stress-induced senescence via activating Nrf2/HO-1 and constraining NF-κB signalling.