Tau-TargetedPROTACs Degrade Pathology-AssociatedTau and Improve Memory in Alzheimer’s Disease Models

This is the authors' abstract. We don't add key points for this paper.

Tau aggregation and hyperphosphorylation are key pathological features of Alzheimer’s disease (AD). Because Tau is intrinsically disordered, conventional small-molecule inhibitors have achieved limited success. Proteolysis-targeting chimeras (PROTACs) enable the targeted proteasomal degradation of previously considered undruggable proteins. We designed Tau-targeted PROTAC candidates using methylene blue (MB) as a recognition moiety for aggregation-prone motifs within the microtubule-binding region and varied the linker lengths and E3 ligase recruitment ligands to optimize degradation efficiency. Cell-based screening revealed that MB-2-VHL1 and MB-2-VHL2 are active degraders. In vivo studies confirmed a reduction in total Tau levels and degradation of phosphorylated Tau (p-Tau). In 3xTg-AD mice, subcutaneous administration of MB-2-VHL2 was associated with reduced hippocampal Tau and p-Tau levels and improved recognition memory and spatial learning. MB-2-VHL2 was also detectable in both serum and brain tissue by LC–MS/MS after subcutaneous administration and did not cause detectable histological or biochemical toxicity. These results indicate that MB-2-VHL2 can reduce both total Tau and p-Tau levels in vivo. Although the reduction in p-Tau appeared more pronounced under our experimental conditions, whether MB-2-VHL2 preferentially targets pathological Tau remains to be determined. Overall, these findings support further optimization and preclinical evaluation of Tau-targeted PROTACs as a potential therapeutic strategy for AD.