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State-Dependent Inhibition of Nav1.8 Sodium Channels by VX-150 and VX-548
Patric Vaelli1, Akie Fujita1, Sooyeon Jo1
1Department of Neurobiology (P.V., A.F., S.J., H.-X.B.Z., T.O., B.P.B.) and Laboratory of Systems Pharmacology and Harvard Program in Therapeutics (X.M.), Harvard Medical School, Boston, Massachusetts.
Molecular Pharmacology
|September 25, 2024
Summary
New pain relief drugs VX-150 and VX-548 target Nav1.8 channels. These compounds exhibit unusual reverse use-dependence, where depolarization relieves inhibition, indicating unique state-dependent binding characteristics for novel pain therapeutics.
Area of Science:
- Neuroscience
- Pharmacology
- Ion Channel Biology
Background:
- Nav1.8 sodium channels are key targets for pain therapeutics due to their presence in pain-sensing neurons.
- VX-150 and VX-548 are Nav1.8 inhibitors demonstrating clinical efficacy for pain relief.
Purpose of the Study:
- To characterize the inhibition of Nav1.8 channels by VX-150 and VX-548.
- To elucidate the unique mechanism of action and state-dependent properties of these compounds.
Main Methods:
- Electrophysiological recordings of human Nav1.8 channels.
- Inhibition assays to determine IC50 values.
- Analysis of drug-channel interactions under varying voltage conditions (use-dependence).
Main Results:
- VX-150m (active metabolite) and VX-548 potently inhibited Nav1.8 channels (IC50s of 15 nM and 0.27 nM, respectively).
- Both compounds displayed reverse use-dependence, with inhibition relieved by depolarization.
- Dissociation and rebinding kinetics suggest strong state-dependence, with weak binding to activated channels.
Conclusions:
- VX-150 and VX-548 are potent Nav1.8 inhibitors with a distinct mechanism of action.
- Their reverse use-dependence highlights unusual state-dependent binding, differing from typical sodium channel blockers.
- This unique characteristic may contribute to their efficacy and safety profile in pain management.
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