Background & Aims

Mutations in ion channels can lead to loss or gain of function, a phenomenon potentially extending to transient receptor potential (TRP) channels, such as TRPA1 [1], whose activation alone is enough to induce pain [2]. Five missense single nucleotide polymorphisms (SNPs) occur within TRPA1, with the second most frequent variant exceeding 10% in the general population. Designated by single-letter amino acid codes, these mutations are R3C, R58T, E179K, K186N, and H1018R. The main aim of this study is to compare these polymorphisms regarding established modes of activation to the most common form.

Methods

The human TRPA1 channel variants (R3C, R58T, E179K, K186N and H1018R) were generated by site directed mutagenesis. The individual mutated channels were transiently expressed in HEK293t cells and probed using calcium microfluorimetry. The transfected cells were exposed to electrophilic agonists (AITC and JT010) and non-electrophilic agonists (Carvacrol and PF–4840154). TRPA1 variants are usually heterozygote, potentially giving rise to assembly of channels which include different TRPA1 monomers. Therefore, the cotransfection of the most frequent form with each of the SNPs was probed by different agonist concentrations.

Results

Each agonist induced concentration-dependent activation of human TRPA1 channels. Notably, among the various agonists, the R58T variant consistently exhibited a higher EC50 in comparison to the other receptors.

Conclusions

Most of the single nucleotide polymorphisms identified in the general population did not alter sensitivity to established modes of activation by pharmacological agonists, with the exception of R58T. This raises the question of whether this might result in a reduced TRPA1 responsiveness in heterozygous subjects, which remains to be tested.

References

1.Meents, Jannis E., Cosmin Ciotu, and Michael J. M. Fischer. 2018. “TRPA1 – a Molecular View.” Journal of Neurophysiology, November. https://doi.org/10.1152/jn.00524.2018.

2. Heber, Stefan, Markus Gold-Binder, Cosmin I. Ciotu, Martin Witek, Nino Ninidze, Hans-Georg Kress, and Michael J. M. Fischer. 2019. “A Human TRPA1-Specific Pain Model.” Journal of Neuroscience 39 (20): 3845–55. https://doi.org/10.1523/JNEUROSCI.3048-18.2019.

Presenting Author

Ciotu I. Cosmin

Poster Authors

Cosmin Ciotu

PhD

Medical University of Vienna

Lead Author

E-mail

Topics

  • Genetics