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CD36 is involved in oleic acid detection by the murine olfactory system.

Oberland S, Ackels T, Gaab S, Pelz T, Spehr J, Spehr M, Neuhaus EM - Front Cell Neurosci (2015)

Bottom Line: In accordance with the described roles of CD36 as fatty acid receptor or co-receptor in other sensory systems, the number of olfactory neurons responding to oleic acid, a major milk component, in Ca(2+) imaging experiments is drastically reduced in young CD36 knock-out mice.Strikingly, we also observe marked age-dependent changes in CD36 localization, which is prominently present in the ciliary compartment only during the suckling period.Our results support the involvement of CD36 in fatty acid detection by the mammalian olfactory system.

View Article: PubMed Central - PubMed

Affiliation: Pharmacology and Toxicology, University Hospital Jena, Friedrich-Schiller-University Jena Jena, Germany ; Cluster of Excellence NeuroCure, Charité-Universitätsmedizin Berlin Berlin, Germany ; Freie Universität-Berlin, Fachbereich Biologie, Chemie und Pharmazie Berlin, Germany.

ABSTRACT
Olfactory signals influence food intake in a variety of species. To maximize the chances of finding a source of calories, an animal's preference for fatty foods and triglycerides already becomes apparent during olfactory food search behavior. However, the molecular identity of both receptors and ligands mediating olfactory-dependent fatty acid recognition are, so far, undescribed. We here describe that a subset of olfactory sensory neurons expresses the fatty acid receptor CD36 and demonstrate a receptor-like localization of CD36 in olfactory cilia by STED microscopy. CD36-positive olfactory neurons share olfaction-specific transduction elements and project to numerous glomeruli in the ventral olfactory bulb. In accordance with the described roles of CD36 as fatty acid receptor or co-receptor in other sensory systems, the number of olfactory neurons responding to oleic acid, a major milk component, in Ca(2+) imaging experiments is drastically reduced in young CD36 knock-out mice. Strikingly, we also observe marked age-dependent changes in CD36 localization, which is prominently present in the ciliary compartment only during the suckling period. Our results support the involvement of CD36 in fatty acid detection by the mammalian olfactory system.

No MeSH data available.


Related in: MedlinePlus

CD36-positive glomeruli in the olfactory bulb. (A) Fluorescence stereo microscopy image (maximum projection) of an olfactory bulb preparation (P9) immunostained for CD36. Ventral view onto the right bulb. Medial side: top; lateral side: bottom. (B) Confocal image (maximum projection) of a vibratome section immunostained for CD36 demonstrating CD36 staining in glomeruli and nerve fibers (P9). (C–F) Fluorescence stereo microscopy images of P8 vibratome sections from rostral to caudal regions of the olfactory bulb immunostained for CD36. Glomeruli are located in ventromedial OB regions. Dotted line encircles the OB in the first image. (d, dorsal; l, lateral; v, ventral; m, medial, consistent for C–F). Scale bars: 100 μm (B), 200 μm (C–F), 500 μm (A).
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Figure 3: CD36-positive glomeruli in the olfactory bulb. (A) Fluorescence stereo microscopy image (maximum projection) of an olfactory bulb preparation (P9) immunostained for CD36. Ventral view onto the right bulb. Medial side: top; lateral side: bottom. (B) Confocal image (maximum projection) of a vibratome section immunostained for CD36 demonstrating CD36 staining in glomeruli and nerve fibers (P9). (C–F) Fluorescence stereo microscopy images of P8 vibratome sections from rostral to caudal regions of the olfactory bulb immunostained for CD36. Glomeruli are located in ventromedial OB regions. Dotted line encircles the OB in the first image. (d, dorsal; l, lateral; v, ventral; m, medial, consistent for C–F). Scale bars: 100 μm (B), 200 μm (C–F), 500 μm (A).

Mentions: Next, we immunostained whole-mount olfactory bulb preparations, and screened the surface for CD36-positive glomeruli. A large subset of glomeruli was labeled at different staining intensities (Figure 3A), clearly outnumbering two glomeruli per bulb typically observed for canonical olfactory neurons with defined receptor identity (Vassar et al., 1994). CD36-positive glomeruli were analyzed in more detail using vibratome slices (Figures 3B–F). CD36 was detected in nerve fibers and axon termini (Figure 3B). We analyzed the distribution of CD36-positive glomeruli from rostral to more caudal parts of the olfactory bulb and found CD36-positive glomeruli predominantly in the ventral and ventromedial region. CD36-positive glomeruli were essentially absent in the most caudal sections of the olfactory bulb (Figures 3C–F).


CD36 is involved in oleic acid detection by the murine olfactory system.

Oberland S, Ackels T, Gaab S, Pelz T, Spehr J, Spehr M, Neuhaus EM - Front Cell Neurosci (2015)

CD36-positive glomeruli in the olfactory bulb. (A) Fluorescence stereo microscopy image (maximum projection) of an olfactory bulb preparation (P9) immunostained for CD36. Ventral view onto the right bulb. Medial side: top; lateral side: bottom. (B) Confocal image (maximum projection) of a vibratome section immunostained for CD36 demonstrating CD36 staining in glomeruli and nerve fibers (P9). (C–F) Fluorescence stereo microscopy images of P8 vibratome sections from rostral to caudal regions of the olfactory bulb immunostained for CD36. Glomeruli are located in ventromedial OB regions. Dotted line encircles the OB in the first image. (d, dorsal; l, lateral; v, ventral; m, medial, consistent for C–F). Scale bars: 100 μm (B), 200 μm (C–F), 500 μm (A).
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Related In: Results  -  Collection

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Figure 3: CD36-positive glomeruli in the olfactory bulb. (A) Fluorescence stereo microscopy image (maximum projection) of an olfactory bulb preparation (P9) immunostained for CD36. Ventral view onto the right bulb. Medial side: top; lateral side: bottom. (B) Confocal image (maximum projection) of a vibratome section immunostained for CD36 demonstrating CD36 staining in glomeruli and nerve fibers (P9). (C–F) Fluorescence stereo microscopy images of P8 vibratome sections from rostral to caudal regions of the olfactory bulb immunostained for CD36. Glomeruli are located in ventromedial OB regions. Dotted line encircles the OB in the first image. (d, dorsal; l, lateral; v, ventral; m, medial, consistent for C–F). Scale bars: 100 μm (B), 200 μm (C–F), 500 μm (A).
Mentions: Next, we immunostained whole-mount olfactory bulb preparations, and screened the surface for CD36-positive glomeruli. A large subset of glomeruli was labeled at different staining intensities (Figure 3A), clearly outnumbering two glomeruli per bulb typically observed for canonical olfactory neurons with defined receptor identity (Vassar et al., 1994). CD36-positive glomeruli were analyzed in more detail using vibratome slices (Figures 3B–F). CD36 was detected in nerve fibers and axon termini (Figure 3B). We analyzed the distribution of CD36-positive glomeruli from rostral to more caudal parts of the olfactory bulb and found CD36-positive glomeruli predominantly in the ventral and ventromedial region. CD36-positive glomeruli were essentially absent in the most caudal sections of the olfactory bulb (Figures 3C–F).

Bottom Line: In accordance with the described roles of CD36 as fatty acid receptor or co-receptor in other sensory systems, the number of olfactory neurons responding to oleic acid, a major milk component, in Ca(2+) imaging experiments is drastically reduced in young CD36 knock-out mice.Strikingly, we also observe marked age-dependent changes in CD36 localization, which is prominently present in the ciliary compartment only during the suckling period.Our results support the involvement of CD36 in fatty acid detection by the mammalian olfactory system.

View Article: PubMed Central - PubMed

Affiliation: Pharmacology and Toxicology, University Hospital Jena, Friedrich-Schiller-University Jena Jena, Germany ; Cluster of Excellence NeuroCure, Charité-Universitätsmedizin Berlin Berlin, Germany ; Freie Universität-Berlin, Fachbereich Biologie, Chemie und Pharmazie Berlin, Germany.

ABSTRACT
Olfactory signals influence food intake in a variety of species. To maximize the chances of finding a source of calories, an animal's preference for fatty foods and triglycerides already becomes apparent during olfactory food search behavior. However, the molecular identity of both receptors and ligands mediating olfactory-dependent fatty acid recognition are, so far, undescribed. We here describe that a subset of olfactory sensory neurons expresses the fatty acid receptor CD36 and demonstrate a receptor-like localization of CD36 in olfactory cilia by STED microscopy. CD36-positive olfactory neurons share olfaction-specific transduction elements and project to numerous glomeruli in the ventral olfactory bulb. In accordance with the described roles of CD36 as fatty acid receptor or co-receptor in other sensory systems, the number of olfactory neurons responding to oleic acid, a major milk component, in Ca(2+) imaging experiments is drastically reduced in young CD36 knock-out mice. Strikingly, we also observe marked age-dependent changes in CD36 localization, which is prominently present in the ciliary compartment only during the suckling period. Our results support the involvement of CD36 in fatty acid detection by the mammalian olfactory system.

No MeSH data available.


Related in: MedlinePlus