The development of benzo- and naphtho-fused quinoline-2,4-dicarboxylic acids as vesicular glutamate transporter (VGLUT) inhibitors reveals a possible role for neuroactive steroids

• Published in: Bioorganic & medicinal chemistry letters 2014-02, Vol.24 (3), p.850-854
• Main Authors: Carrigan, Christina N., Patel, Sarjubhai A., Cox, Holly D., Bolstad, Erin S., Gerdes, John M., Smith, Wesley E., Bridges, Richard J., Thompson, Charles M.
• Format: Article
• Language: English
• Subjects: Binding, Competitive - drug effects; Cyclization; Dicarboxylic Acids - chemical synthesis; Dicarboxylic Acids - chemistry; Dicarboxylic Acids - pharmacology; Dose-Response Relationship, Drug; Glutamate; Inhibitory Concentration 50; Models, Molecular; Molecular Structure; Naphthols - chemical synthesis; Naphthols - chemistry; Naphthols - pharmacology; Neuroactive steroids; Neurotransmitter Agents - chemical synthesis; Neurotransmitter Agents - chemistry; Neurotransmitter Agents - pharmacology; Pregnanolone - chemistry; Pregnanolone - pharmacokinetics; Quinoline 2,4-dicarboxylic acid; Quinolines - chemical synthesis; Quinolines - chemistry; Quinolines - pharmacology; Reference Standards; Synaptic vesicle; Vesicular Glutamate Transport Proteins - antagonists & inhibitors; VGLUT
• ISSN: 0960-894X; 1464-3405
• DOI: 10.1016/j.bmcl.2013.12.086

Substituted quinoline-2,4-dicarboxylates (QDCs) are conformationally-restricted mimics of glutamate that were previously reported to selectively block the glutamate vesicular transporters (VGLUTs). We find that expanding the QDC scaffold to benzoquinoline dicarboxylic acids (BQDC) and naphthoquinoline dicarboxylic acids (NQDCs) improves inhibitory activity with the NQDCs showing IC50∼70μM. Modeling overlay studies showed that the polycyclic QDCs resembled steroid structures and led to the identification and testing of estrone sulfate, pregnenolone sulfate and pregnanolone sulfate that blocked the uptake of l-Glu by 50%, 70% and 85% of control, respectively. Pregnanolone sulfate was further characterized by kinetic pharmacological determinations that demonstrated competitive inhibition and a Ki of ≈20μM.