Targeting transthyretin tetramer with a novel blood-brain barrier-penetrating small-molecule stabilizer for the treatment of Alzheimer's disease.

The stability of the transthyretin (TTR) tetramer is critical for regulating cerebral amyloid-β (Aβ) homeostasis in Alzheimer's disease (AD). Stable TTR tetramer can directly bind Aβ and promote its clearance from the brain. However, current TTR tetramer stabilizers lack blood-brain barrier (BBB) penetration, limiting their clinical translation. Therefore, to fully realize the therapeutic potential of TTR in AD, novel TTR tetramer stabilizers with superior BBB penetration must be discovered. Here, we aim to identify TTR tetramer stabilizers with BBB penetration via a multidimensional virtual screening workflow, and perform preliminary validation of their biological activities. Finally, Z1097086893 was identified as the lead compound. In vitro, the compound exhibited significant BBB penetration and robust TTR tetramer stabilization activity. In vivo, Z1097086893 also crossed the BBB. MSI showed localization to the choroid plexus within the ventricular system, the principal site of TTR synthesis and secretion in the brain. In the 5xFAD mouse model, the compound significantly reduced hippocampal Aβ plaque burden, alleviated neuronal injury, and rescued spatial learning and recognition memory deficits. Safety assessments confirmed that Z1097086893 was well tolerated at therapeutic doses, with no detectable drug-induced organ toxicity or abnormalities in liver and kidney function. Our findings validate cerebral TTR tetramer stabilization as a promising therapeutic strategy for AD, and provide a lead compound for further clinical translation. Furthermore, the BBB-first screening workflow established in this work offers a generalizable technical framework for the development of brain-targeted therapeutics for AD.