Dual 5-HT6/SERT ligands for mitigating neuropsychiatric symptoms of dementia exerting neuroprotection against amyloid-β toxicity, memory preservation, and antidepressant-like properties

In light of the biological targets alterations in dementia patients suffering from neuropsychiatric symptoms, particularly in the 5-HT₆ receptor and SERT transporters, this study aimed to develop dual-acting molecules targeting both these targets. By combining a 5-substituted indole with piperazine scaffolds, we synthesized molecules with nanomolar affinities for these sites, avoiding interaction with off-targets detrimental to dementia patients. Preliminary pharmacodynamic and ADMET assays let the identification of compound 15 as a lead molecule. In vitro studies showed that 15 provided neuroprotection against Aβ toxicity and reduced the levels of proapoptotic enzymes: Caspase 3 and 7. In vivo, 15 reversed MK-801-induced memory deficits and exhibited antidepressant-like effects. Further studies showed that acute administration of compound 15 at a dose of 5 mg/kg increased BDNF levels, which are crucial for supporting neuronal survival and potentially slowing cognitive decline in dementia. These findings suggest 15's potential as a therapeutic for behavioral and psychological symptoms of dementia (BPSD), warranting further investigation.