title: Clavulanic acid increases dopamine release in neuronal cells through a mechanism involving enhanced vesicle trafficking.
abstract: Clavulanic acid is a CNS-modulating compound with exceptional blood-brain barrier permeability and safety profile. Clavulanic acid has been proposed to have anti-depressant activity and is currently entering Phase IIb clinical trials for the treatment of Major Depressive Disorder (MDD). Studies have also shown that clavulanic acid suppresses anxiety and enhances sexual functions in rodent and primate models by a mechanism involving central nervous system (CNS) modulation, although its detailed mechanism of action has yet to be elucidated. To further examine its potential as a CNS modulating agent as well as its mechanism of action, we investigated the effects of clavulanic acid in neuronal cells. Our results indicate that clavulanic acid enhances dopamine release in PC12 and SH-SY5Y cells without affecting dopamine synthesis. Furthermore, using affinity chromatography we were able to identify two proteins, Munc18-1 and Rab4 that potentially bind to clavulanic acid and play a critical role in neurosecretion and the vesicle trafficking process. Consistent with this result, an increase in the translocation of Munc18-1 and Rab4 from the cytoplasm to the plasma membrane was observed in clavulanic acid treated cells. Overall, these data suggest that clavulanic acid enhances dopamine release in a mechanism involving Munc18-1 and Rab4 modulation and warrants further investigation of its therapeutic use in CNS disorders, such as depression.
authors.affiliation: Rexahn Pharmaceuticals, Inc., Rockville, MD 20850, United States. Electronic address: chung@rexahn.com.
authors.forename: Gina Chun
authors.initials: GC
authors.lastname: Kost
authors.affiliation: Department of Biochemistry and Molecular Biology, School of Medicine and Health Sciences, University of North Dakota, United States.
authors.forename: Senthil
authors.initials: S
authors.lastname: Selvaraj
authors.affiliation: Rexahn Pharmaceuticals, Inc., Rockville, MD 20850, United States.
authors.forename: Young Bok
authors.initials: YB
authors.lastname: Lee
authors.affiliation: Rexahn Pharmaceuticals, Inc., Rockville, MD 20850, United States.
authors.forename: Deog Joong
authors.initials: DJ
authors.lastname: Kim
authors.affiliation: Rexahn Pharmaceuticals, Inc., Rockville, MD 20850, United States.
authors.forename: Chang-Ho
authors.initials: CH
authors.lastname: Ahn
authors.affiliation: Department of Biochemistry and Molecular Biology, School of Medicine and Health Sciences, University of North Dakota, United States.
authors.forename: Brij B
authors.initials: BB
authors.lastname: Singh
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001812:Blood-Brain Barrier / Q000187:drug effects; D002460:Cell Line; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000378:metabolism; D019818:Clavulanic Acid / Q000494:pharmacology*; D003593:Cytoplasm / Q000378:metabolism; D004298:Dopamine / Q000378:metabolism*; D005089:Exocytosis / Q000187:drug effects; D005455:Fluorescent Antibody Technique; D006801:Humans; D051938:Munc18 Proteins / Q000378:metabolism; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D016716:PC12 Cells; D011485:Protein Binding; D051381:Rats; D013572:Synaptic Vesicles / Q000187:drug effects / Q000378:metabolism*; D020691:rab GTP-Binding Proteins / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D051938:Munc18 Proteins; D019818:Clavulanic Acid; D020691:rab GTP-Binding Proteins; D004298:Dopamine