Olfactory mucosa-expressed organic anion transporter, Oat6, manifests high affinity interactions with odorant organic anions

doi:10.1016/j.bbrc.2006.10.136

Biochemical and Biophysical Research Communications

Volume 351, Issue 4, 29 December 2006, Pages 872-876

https://doi.org/10.1016/j.bbrc.2006.10.136 Get rights and content

Abstract

We have characterized the expression of organic anion transporter 6, Oat6 (slc22a20), in olfactory mucosa, as well as its interaction with several odorant organic anions. In situ hybridization reveals diffuse Oat6 expression throughout olfactory epithelium, yet olfactory neurons laser-capture microdissected from either the main olfactory epithelium (MOE) or the vomeronasal organ (VNO) did not express Oat6 mRNA. These data suggest that Oat6 is expressed in non-neuronal cells of olfactory tissue, such as epithelial and/or other supporting cells. We next investigated interaction of Oat6 with several small organic anions that have previously been identified as odortype components in mouse urine. We find that each of these compounds, propionate, 2- and 3-methylbutyrate, benzoate, heptanoate, and 2-ethylhexanoate, inhibits Oat6-mediated uptake of a labeled tracer, estrone sulfate, consistent with their being Oat6 substrates. Previously, we noted defects in the renal elimination of odortype and odortype-like molecules in Oat1 knockout mice. The finding that such molecules interact with Oat6 raises the possibility that odorants secreted into the urine through one OAT-mediated mechanism (Eraly et al., JBC 2006) are transported through the olfactory mucosa through another OAT-mediated mechanism. Oat6 might play a direct or indirect role in olfaction, such as modulation of the availability of odorant organic anions at the mucosal surface for presentation to olfactory neurons or facilitation of delivery to a distal site of chemosensation, among other possibilities that we discuss.

Section snippets

Materials and methods

Organic anion transporter 6 (Oat6 and Oat1). Capped cRNA was synthesized from a linearized plasmid DNA (mOat6, Image clone ID: 6309674; mOat1, Image clone ID: 4163278) using mMessage mMachine in vitro transcription kit (Ambion, Inc., Austin, TX).

Oat6 expression in nasal mucosa. Small sections of whole epithelia were microdissected from the main olfactory epithelium (MOE) and the vomeronasal organ (VNO) of C57BL/6 mice. RNA was extracted using a Stratagene Absolutely RNA Nanoprep Kit (La Jolla,

Oat6 expression in nasal mucosa

Previously it was shown that Oat6 is expressed in nasal mucosa [7], but its localization in the tissue was unclear. To clarify this issue, we performed in situ hybridization of coronal sections through the nasal mucosa with an Oat6 probe and a control olfactory marker protein (OMP) probe. As expected, an intense OMP-specific signal was noted throughout the olfactory epithelium. By comparison, we found the Oat6 signal to be weaker but with a similar distribution throughout the olfactory

Discussion

In this work, we have clarified the localization and characterized functional properties of the olfactory organic anion transporter, Oat6. In situ hybridization (Fig. 1) revealed diffuse expression for Oat6 throughout the olfactory epithelium. Analysis of individual olfactory neurons laser-captured from either the main olfactory epithelium (MOE) or the vomeronasal organ (VNO) (Fig. 2) indicated that Oat6 is expressed in non-neuronal cells of both these structures. All of the volatile carboxylic

Acknowledgments

This work was supported by NIH Grants AI057695 and HD40011 to S.K.N., and DK064839 and DK075486 to S.A.E. We also wish to thank the Stowers Lab.

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^☆: Abbreviations: OAT, organic anion transporter; ES, estrone sulfate; PAH, p-aminohippurate.

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Olfactory mucosa-expressed organic anion transporter, Oat6, manifests high affinity interactions with odorant organic anions☆

Abstract

Section snippets

Materials and methods

Oat6 expression in nasal mucosa

Discussion

Acknowledgments

Biochim. Biophys. Acta (BBA)—Biomembr.

Pharmacol. Ther.

E. J. Pharm. Sci.

Biochem. Biophys. Res. Commun.

J. Biol. Chem.

Cell

Transport of organic anions across the basolateral membrane of proximal tubule cells

Rev. Physiol. Biochem. Pharmacol.

The molecular pharmacology of organic anion transporters: from DNA to FDA?

Mol. Pharmacol.