Phenylalanine-Derived β-Lactam TRPM8 Modulators. Configuration Effect on the Antagonist Activity

Area of Science:

• Pharmacology
• Neuroscience
• Medicinal Chemistry

Background:

• Transient receptor potential cation channel subfamily M member 8 (TRPM8) is a Ca2+ non-selective ion channel involved in pain and cancer.
• Chiral β-lactam derivatives were previously identified as potential TRPM8 antagonists.
• The influence of stereogenic centers on antagonist activity required further investigation.

Purpose of the Study:

• To synthesize and characterize four diastereoisomeric β-lactam derivatives.
• To evaluate the TRPM8 antagonist properties of these isomers.
• To determine the structure-activity relationship concerning stereochemistry.

Main Methods:

• Synthesis and characterization of four diastereoisomeric β-lactam derivatives.
• Microfluorography assays to measure menthol-induced Ca2+ entry.
• Patch-Clamp electrophysiology to confirm inhibitory concentrations (IC50).
• Receptor selectivity assays against other TRP family members.
• Neuronal excitability assays in primary rat dorsal root ganglion (DRG) neurons.
• Molecular docking studies.

Main Results:

• All four diastereoisomers inhibited menthol-induced Ca2+ entry into cells.
• Potency varied, with the 3R,4R,2'R isomer being the most potent (low nanomolar IC50).
• Compounds exhibited high selectivity for TRPM8 over other TRP channels.
• The most potent isomers did not affect neuronal excitability in DRG neurons.
• Docking studies suggested a unique binding site within the TRPM8 channel pore.

Conclusions:

• Stereochemistry significantly influences the TRPM8 antagonist activity of these β-lactam derivatives.
• The most potent diastereoisomer represents a highly selective and specific TRPM8 antagonist.
• These findings provide a basis for developing novel TRPM8-targeted therapeutics for pain and other conditions.
• The identified compounds may act via a distinct mechanism compared to existing antagonists.