Human TRPV1 structure and inhibition by the analgesic SB-366791

Abstract

Pain therapy has remained conceptually stagnant since the opioid crisis, which highlighted the dangers of treating pain with opioids. An alternative addiction-free strategy to conventional painkiller-based treatment is targeting receptors at the origin of the pain pathway, such as transient receptor potential (TRP) ion channels. Thus, a founding member of the vanilloid subfamily of TRP channels, TRPV1, represents one of the most sought-after pain therapy targets. The need for selective TRPV1 inhibitors extends beyond pain treatment, to other diseases associated with this channel, including psychiatric disorders. Here we report the cryo-electron microscopy structures of human TRPV1 in the apo state and in complex with the TRPV1-specific nanomolar-affinity analgesic antagonist SB-366791. SB-366791 binds to the vanilloid site and acts as an allosteric hTRPV1 inhibitor. SB-366791 binding site is supported by mutagenesis combined with electrophysiological recordings and can be further explored to design new drugs targeting TRPV1 in disease conditions.

Structural basis of TRPV1 modulation by endogenous bioactive lipids

“…Movement of the S4-S5 linker enables the S5 and S6 helices to move away from the pore axis while providing space to accommodate a π-α helix transition in S6, which is associated with the loss of hydrophobic interactions between M682 and the S4-S5 linker (Supplementary Figure 6b). At the same time, reorientation of Y511 is necessary, but not sufficient, to facilitate gating movements, consistent with the observation that TRPV1 antagonists also induce similar reorientation of Y511 5,11 .…”

“…interactions between M682 and the S4-S5 linker (Supplementary Figure 6b). At the same time, reorientation of Y511 is necessary, but not sufficient, to facilitate gating movements, consistent with the observation that TRPV1 antagonists also induce similar reorientation of Y511 5,11 .…”

“…Indeed, the B-factor surrounding M682 suggests that this residue is dynamic and thus sufficiently malleable to pass ions. Importantly, π-α transitions are seen when agonists, but not antagonists, occupy the VBP 5,6,11 , and these data now show that ejection of the resident lipid is also sufficient to support this transition. Interestingly, the main difference between 4° and 25° C structures was seen in the density of the M682 side chain, which was less well-resolved in the latter, implying a more dynamic nature at higher temperature.…”

“…In both cryo-EM structures the vanilloid pocket is, indeed, unoccupied by either a resident PI lipid or capsaicin (Figure 1, Supplementary Figure 1). Previous functional and structural studies have identified tyrosine 511 (Y511) as a residue whose reorientation towards the vanilloid pocket correlates with ejection of the resident PI lipid upon ligand binding 5,6,11 . Interestingly, we observed that Y511 is flipped toward the binding pocket in these two structures, akin to what is seen in the agonist-bound state, demonstrating that reorientation of this fiducial side chain primarily reflects ejection of the resident lipid (Figure 1b).…”

TRPV3 activation by different agonists accompanied by lipid dissociation from the vanilloid site

“…6, A and B). The vanilloid site was originally discovered in TRPV1, where it binds agonists, such as capsaicin or resiniferatoxin, competitive antagonists, like capsazepine and analgesic SB-366791, or PI lipid in the apo state (35,36,(40)(41)(42)(43). The active role of the vanilloid-site lipid was also proposed in temperature gating of TRPV1 (36,41) but was clearly demonstrated for the temperature gating of wild-type mouse TRPV3, where heat-induced channel opening was accompanied by the dissociation of this lipid (29).…”