ASO-18

ASO-18 is a cross-species antisense oligonucleotide (ASO) GapmeR designed to target and knock down the expression of FK506-binding protein 51 (FKBP51), a co-chaperone of the 90kDa heat shock protein (Hsp90). Developed by researchers at the University of South Florida, ASO-18 targets conserved regions of the human *FKBP5* and mouse *Fkbp5* genes. FKBP51 has been implicated in stabilizing neurotoxic tau species in tauopathies such as Alzheimer's disease. In preclinical studies, ASO-18 demonstrated high potency and selectivity, reducing FKBP51 levels without affecting the close homolog FKBP52. Administration of ASO-18 in neuronal models and tau transgenic mice led to significant reductions in total tau and phospho-tau levels, suggesting potential therapeutic utility for tauopathies and related neuropsychiatric disorders.