Targeting NOX4 with Quercetagetin-PLGA nanomaterials: a novel therapeutic strategy for Alzheimer's disease.

This study aims to address NOX4 (NADPH oxidase 4)-driven oxidative injury in Alzheimer's disease (AD) and the poor bioavailability of the natural flavonoid Quercetagetin, we developed an α7 nicotinic acetylcholine receptor (α7-nAChR)-targeted, Quercetagetin-loaded PLGA nanocarrier (PLGA@Quercetagetin@α7-nAChR) for receptor-mediated delivery, NOX4 suppression, and neuroprotection. Using the GSE97760 dataset, bioinformatic screening combined with LASSO regression was performed to identify candidate targets. Single-cell RNA sequencing (scRNA-seq) with pseudotime analysis was applied to delineate cell type-resolved and trajectory-associated expression patterns. Nanoparticles were fabricated by a double-emulsion method and characterized for physicochemical properties. In an Aβ-induced HT-22 neuronal injury model, genetic perturbation, western blotting, and flow cytometry were used to validate the pathogenic role of NOX4 and to evaluate the pharmacological efficacy of the nanoplatform. NOX4 emerged as the key gene, showing enriched expression in oligodendrocytes and endothelial cells and an increase along the inferred disease-associated trajectory. In vitro, Aβ stimulation upregulated NOX4, whereas NOX4 knockdown or Quercetagetin treatment alleviated Aβ-induced cytotoxicity and apoptosis. The nanoparticles exhibited an average diameter and sustained drug release over 72 h. α7-nAChR targeting enhanced neuronal uptake by ~ fivefold, markedly reduced NOX4 mRNA levels, and decreased the apoptotic rate from 18.3% to 5.0%. Notably, encapsulation also mitigated the hepatorenal toxicity observed with high-dose free Quercetagetin. These in vitro findings suggest NOX4 as a potential target in AD, and the PLGA@Quercetagetin@α7-nAChR nanoplatform shows improved cellular uptake and reduced short-term toxicity compared to free drug. However, claims regarding brain targeting and translational potential are limited by the absence of in vivo validation, non-targeted controls, drug exposure normalization, and key formulation parameters (e.g., encapsulation efficiency). Future in vivo studies are required to substantiate this targeted strategy for AD.