Characterization and Optimization of the Novel Transient Receptor Potential Melastatin 2 Antagonist tatM2NX
I Cruz-Torres1, D S Backos2, P S Herson3
1Departments of Pharmacology (I.C.-T., P.S.H.) and Anesthesiology (P.S.H.) and Neuronal Injury & Plasticity Program (I.C.-T., P.S.H.), University of Colorado School of Medicine, Aurora, Colorado; and Department of Pharmaceutical Sciences, University of Colorado Skaggs School of Pharmacy and Pharmaceutical Sciences, Aurora, Colorado (D.S.B.) ivelisse.cruz-torres@ucdenver.edu.
Abstract:
Transient receptor potential melastatin 2 (TRPM2) is a calcium-permeable channel activated by adenosine diphosphate ribose metabolites and oxidative stress. TRPM2 contributes to neuronal injury in the brain caused by stroke and cardiac arrest among other diseases including pain, inflammation, and cancer. However, the lack of specific inhibitors hinders the study of TRPM2 in brain pathophysiology. Here, we present the design of a novel TRPM2 antagonist, tatM2NX, which prevents ligand binding and TRPM2 activation. We used mutagenesis of tatM2NX to determine the structure-activity relationship and antagonistic mechanism on TRPM2 using whole-cell patch clamp and Calcium imaging in human embryonic kidney 293 cells with stable human TRPM2 expression. We show that tatM2NX inhibits over 90% of TRPM2 channel currents at concentrations as low as 2 μM. Moreover, tatM2NX is a potent antagonist with an IC50 of 396 nM. Our results from tatM2NX mutagenesis indicate that specific residues within the tatM2NX C terminus are required to confer antagonism on TRPM2. Therefore, the peptide tatM2NX represents a new tool for the study of TRPM2 function in cell biology and enhances our understanding of TRPM2 in disease. SIGNIFICANCE STATEMENT: TatM2NX is a potent TRPM2 channel antagonist with the potential for clinical benefit in neurological diseases. This study characterizes interactions of tatM2NX with TRPM2 and the mechanism of action using structure-activity analysis.
Insights
A novel peptide, tatM2NX, effectively inhibits the TRPM2 channel, a key player in neurological injury. This discovery offers a new tool for studying TRPM2 and potential therapeutic benefits in brain diseases.
Area of Science:
- Neuroscience
- Molecular Biology
- Pharmacology
Background:
- Transient receptor potential melastatin 2 (TRPM2) channels are implicated in neuronal injury, pain, inflammation, and cancer.
- TRPM2 activation by oxidative stress and ADP-ribose metabolites contributes to brain damage in conditions like stroke.
- A lack of specific TRPM2 inhibitors has limited research into its role in brain pathophysiology.
Purpose of the Study:
- To design and characterize a novel TRPM2 antagonist, tatM2NX.
- To elucidate the structure-activity relationship and mechanism of antagonism for tatM2NX on TRPM2.
- To provide a new research tool for investigating TRPM2 function and its role in disease.
Main Methods:
- Design and mutagenesis of the tatM2NX peptide.
- Whole-cell patch clamp electrophysiology to measure TRPM2 channel currents.
- Calcium imaging in HEK293 cells stably expressing human TRPM2.
- Structure-activity relationship analysis.
Main Results:
- TatM2NX potently inhibits TRPM2 channel activity, with over 90% inhibition at 2 μM.
- The antagonist exhibits an IC50 of 396 nM for TRPM2.
- Mutagenesis studies identified specific C-terminal residues of tatM2NX crucial for TRPM2 antagonism.
- The study characterized the interaction and mechanism of action between tatM2NX and TRPM2.
Conclusions:
- TatM2NX is a potent and specific TRPM2 channel antagonist.
- The peptide tatM2NX serves as a valuable new tool for studying TRPM2 in cellular processes and disease.
- TatM2NX holds potential for clinical applications in neurological disorders involving TRPM2.
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