Re-engineering a neuroprotective, clinical drug as a procognitive agent with high in vivo potency and with GABAA potentiating activity for use in dementia.

Abstract

BACKGROUND:

Synaptic dysfunction is a key event in pathogenesis of neurodegenerative diseases such as Alzheimer's disease (AD) where synapse loss pathologically correlates with cognitive decline and dementia. Although evidence suggests that aberrant protein production and aggregation are the causative factors in familial subsets of such diseases, drugs singularly targeting these hallmark proteins, such as amyloid-β, have failed in late stage clinical trials. Therefore, to provide a successful disease-modifying compound and address synaptic dysfunction and memory loss in AD and mixed pathology dementia, we repurposed a clinically proven drug, CMZ, with neuroprotective and anti-inflammatory properties via addition of nitric oxide (NO) and cGMP signaling property.

RESULTS:

The novel compound, NMZ, was shown to retain the GABAA potentiating actions of CMZ in vitro and sedative activity in vivo. Importantly, NMZ restored LTP in hippocampal slices from AD transgenic mice, whereas CMZ was without effect. NMZ reversed amnestic blockade of acetylcholine receptors by scopolamine as well as NMDA receptor blockade by a benzodiazepine and a NO synthase inhibitor in the step-through passive avoidance (STPA) test of learning and working memory. A PK/PD relationship was developed based on STPA analysis coupled with pharmacokinetic measures of drug levels in the brain: at 1 nM concentration in brain and plasma, NMZ was able to restore memory consolidation in mice.

CONCLUSION:

Our findings show that NMZ embodies a promising pharmacological approach targeting synaptic dysfunction and opens new avenues for neuroprotective intervention strategies in mixed pathology AD, neurodegeneration, and dementia.

• Authors: Jia Luo, Sue H Lee, Lawren VandeVrede, Zhihui Qin, Sujeewa Piyankarage, Ehsan Tavassoli, Rezene T Asghodom, Manel Ben Aissa, Mauro Fà, Ottavio Arancio, Lan Yue, David R Pepperberg, Gregory R J Thatcher
• Journal: BMC neuroscience (BMC Neurosci) Vol. 16 Pg. 67 (Oct 19 2015) ISSN: 1471-2202 [Electronic] England
• PMID: 26480871 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)

Chemical References

• GABA-A Receptor Agonists
• Neuroprotective Agents
• Nootropic Agents
• Chlormethiazole
• Nitric Oxide
• CREB-Binding Protein
• Cyclic GMP

Topics

• Alzheimer Disease (drug therapy)
• Animals
• CREB-Binding Protein (metabolism)
• Chlormethiazole (analogs & derivatives)
• Cyclic GMP (metabolism)
• Disease Models, Animal
• Drug Repositioning (methods)
• GABA-A Receptor Agonists (pharmacokinetics, pharmacology)
• Hippocampus (drug effects)
• Long-Term Potentiation (drug effects)
• Male
• Mice
• Mice, Transgenic
• Neuroprotective Agents (pharmacokinetics, pharmacology)
• Nitric Oxide (metabolism)
• Nootropic Agents (pharmacokinetics, pharmacology)
• Signal Transduction (drug effects)
• Synapses (drug effects, pathology)
• Xenopus laevis