Membrane‐tethered peptides patterned after the TRP domain (TRPducins) selectively inhibit TRPV1 channel activity

Abstract

The transient receptor potential vanilloid 1 (TRPV1) channel is a thermosensory receptor implicated in diverse physiological and pathological processes. The TRP domain, a highly conserved region in the C terminus adjacent to the internal channel gate, is critical for subunit tetramerization and channel gating. Here, we show that cell-penetrating, membrane-anchored peptides patterned after this protein domain are moderate and selective TRPV1 antagonists both in vitro and in vivo, blocking receptor activity in intact rat primary sensory neurons and their peripheral axons with mean decline time of 30 min. The most potent lipopeptide, TRP-p5, blocked all modes of TRPV1 gating with micromolar efficacy (IC(50)<10 μM), without significantly affecting other thermoTRP channels. In contrast, its retrosequence or the corresponding sequences of other TRPV channels did not alter TRPV1 channel activity (IC(50)>100 μM). TRP-p5 did not affect the capsaicin sensitivity of the vanilloid receptor. Our data suggest that TRP-p5 interferes with protein-protein interactions at the level of the TRP domain that are essential for the "conformational" change that leads to gate opening. Therefore, these palmitoylated peptides, which we termed TRPducins, are noncompetitive, voltage-independent, sequence-specific TRPV1 blockers. Our findings indicate that TRPducin-like peptides may embody a novel molecular strategy that can be exploited to generate a selective pharmacological arsenal for the TRP superfamily of ion channels.

Intracellular Proton-mediated Activation of TRPV3 Channels Accounts for the Exfoliation Effect of α-Hydroxyl Acids on Keratinocytes

“…Our data also suggest that the strong inhibition of the TRPV3 current at highly acidic pH levels may not be accounted for by simple conductance inhibition, indicating that an inhibitory effect of proton on channel gating may also exist. A second pH sensing domain or general charge effects on the TRP domain may contribute to this inhibition (82).…”

The G Protein–Coupled Receptor–Transient Receptor Potential Channel Axis: Molecular Insights for Targeting Disorders of Sensation and Inflammation

“…TRPV1 TRPducins selectively inhibits TRPV1 over other TRPV channels and can block heat-, acid-, and voltage-evoked TRPV1 currents. This process inhibits CGRP release from cultured neurons and lowers chemically-but not mechanicallyinduced pain (Valente et al, 2011). Similarly, small PKC sequence peptides fused to membrane-permeating TAT sequences can selectively inhibit specific PKC isoforms and have been shown to reduce ischemic heart damage (Chen et al, 2001).…”

The Region Adjacent to the C-end of the Inner Gate in Transient Receptor Potential Melastatin 8 (TRPM8) Channels Plays a Central Role in Allosteric Channel Activation

“…Molecular Model Building-The molecular model for TRPM8 was modeled using the structures of the TRPV1 ion channel in the closed (Protein Data Bank code 3J5P) and open state (Protein Data Bank code 3J5R) determined by electron microscopy at 3.4-Å resolution (28). Sequence alignment between rat TRPV1 and TRPM8 was performed with ClustalO (30) from the European Bioinformatic Institute (EBI).…”

“…A recent study in TRPV1 has shown that the TRP domain is primarily involved in the allosteric activation of the gate of the channel (27). Noteworthy, a peptide patterned after the TRP domain of TRPV1 selectively blocked TRPV1 activity (28), supporting the tenet that the TRP domain is involved in protein-protein interactions that are central for coupling stimuli sensing to gating (15). Moreover, in TRPM8, the TRP domain appears directly involved in phosphatidylinositol 4,5-bisphosphate-mediated regulation (12).…”