Glycosylated Neurotensin Analogues Exhibit Sub-picomolar Anticonvulsant Potency in a Pharmacoresistant Model of Epilepsy

The glycosylation of neuroactive peptides is a promising strategy to treat neurological and psychiatric disorders. Herein we investigated the effects of site-specific glycosylation of neurotensin (NT). The glycosylated analogues have low-nanomolar affinities and agonist activities toward NTS1, and suppress seizures with sub-picomolar potency. Our work points to a new research direction of exploring BBB-permeable NT analogues as potential first-in-class antiepileptic drugs. Neurotensin (NT) is an endogenous neuropeptide involved in a variety of central and peripheral neuromodulatory effects. Herein we show the effects of site-specific glycosylation on the in vitro and in vivo pharmacological properties of this neuropeptide. NT analogues containing O-linked disaccharides (β-melibiose and α-TF antigen) or β-lactose units linked by a PEG3 spacer were designed and chemically synthesized using Fmoc chemistry. For the latter analogue, Fmoc-Glu-(β-Lac-PEG3-amide) was prepared. Our results indicate that the addition of the disaccharides does not negatively affect the sub-nanomolar affinity or the low-nanomolar agonist potency for the neurotensin receptor subtype 1 (NTS1). Interestingly, three glycosylated analogues exhibited sub-picomolar potency in the 6 Hz limbic seizure mouse model of pharmacoresistant epilepsy following intracerebroventricular administration. Our results suggest for the first time that chemically modified NT analogues may lead to novel antiepileptic therapies.