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Differential Anatomical Expression of Ganglioside GM1 Species Containing d18:1 or d20:1 Sphingosine Detected by MALDI Imaging Mass Spectrometry in Mature Rat Brain.

Weishaupt N, Caughlin S, Yeung KK, Whitehead SN - Front Neuroanat (2015)

Bottom Line: Across layers of the sensory cortex, opposing expression gradients were found for GM1d18:1 and GM1d20:1.By far the highest GM1d18:1/d20:1 ratio was found in the amygdala.Differential expression of GM1 with d18:1- or d20:1-sphingosine bases in the adult rat brain suggests tight regulation of expression and points toward a distinct functional relevance for each of these GM1 species in neuronal processes.

View Article: PubMed Central - PubMed

Affiliation: Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, University of Western Ontario, London ON, Canada.

ABSTRACT
GM1 ganglioside plays a role in essential neuronal processes, including differentiation, survival, and signaling. Yet, little is known about GM1 species with different sphingosine bases, such as the most abundant species containing 18 carbon atoms in the sphingosine chain (GM1d18:1), and the less abundant containing 20 carbon atoms (GM1d20:1). While absent in the early fetal brain, GM1d20:1 continues to increase throughout pre- and postnatal development and into old age, raising questions about the functional relevance of the GM1d18:1 to GM1d20:1 ratio. Matrix-assisted laser desorption/ionization imaging mass spectrometry is a novel technology that allows differentiation between these two GM1 species and quantification of their expression within an anatomical context. Using this technology, we find GM1d18:1/d20:1 expression ratios are highly specific to defined anatomical brain regions in adult rats. Thus, the ratio was significantly different among different thalamic nuclei and between the corpus callosum and internal capsule. Differential GM1d18:1/GM1d20:1 ratios measured in hippocampal subregions in rat brain complement previous studies conducted in mice. Across layers of the sensory cortex, opposing expression gradients were found for GM1d18:1 and GM1d20:1. Superficial layers demonstrated lower GM1d18:1 and higher GM1d20:1 signal than other layers, while in deep layers GM1d18:1 expression was relatively high and GM1d20:1 expression low. By far the highest GM1d18:1/d20:1 ratio was found in the amygdala. Differential expression of GM1 with d18:1- or d20:1-sphingosine bases in the adult rat brain suggests tight regulation of expression and points toward a distinct functional relevance for each of these GM1 species in neuronal processes.

No MeSH data available.


Related in: MedlinePlus

Expression images of GM1d18:1 (green) and GM1d20:1 (red) showed relatively high GM1d18:1 expression within the amygdala, while GM1d20:1 expression was low within the hypothalamus and amygdala (A). Scale bar = 4 mm. A schematic cross section shows regions included in ROIs from which mass spectra were generated for the amygdala and hypothalamus (B). AHiAL, amygdalohippocampal area, anteriolateral part; BMP, basomedial amygdaloid nucleus, posterior part; BLP, basolateral amygdaloid nucleus, posterior part; DM, dorsomedial hypothalamic nucleus; MePD, medial amygdaloid nucleus, posterodorsal part; MePV, medial amygdaloid nucleus, posteroventral part; PeF, perifornical nucleus; PH, posterior hypothalamic nucleus; PLH, peduncular part of lateral hypothalamus; PMCo, posteromedial cortical amygdaloid nucleus; PMV, premammillary nucleus, ventral part; STiA, bed nucleus of the stria terminalis, amygdaloid division. The GM1d18:1/GM1d20:1 ratio was significantly higher within the amygdala than the hypothalamus (Mann–Whitney test, ∗∗∗∗p < 0.0001, C).
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Figure 6: Expression images of GM1d18:1 (green) and GM1d20:1 (red) showed relatively high GM1d18:1 expression within the amygdala, while GM1d20:1 expression was low within the hypothalamus and amygdala (A). Scale bar = 4 mm. A schematic cross section shows regions included in ROIs from which mass spectra were generated for the amygdala and hypothalamus (B). AHiAL, amygdalohippocampal area, anteriolateral part; BMP, basomedial amygdaloid nucleus, posterior part; BLP, basolateral amygdaloid nucleus, posterior part; DM, dorsomedial hypothalamic nucleus; MePD, medial amygdaloid nucleus, posterodorsal part; MePV, medial amygdaloid nucleus, posteroventral part; PeF, perifornical nucleus; PH, posterior hypothalamic nucleus; PLH, peduncular part of lateral hypothalamus; PMCo, posteromedial cortical amygdaloid nucleus; PMV, premammillary nucleus, ventral part; STiA, bed nucleus of the stria terminalis, amygdaloid division. The GM1d18:1/GM1d20:1 ratio was significantly higher within the amygdala than the hypothalamus (Mann–Whitney test, ∗∗∗∗p < 0.0001, C).

Mentions: Based on the relative expression of both GM1 species in molecular images, the hypothalamus had a relatively lower content of GM1 in comparison to the thalamus, the hippocampus, cortical regions and the amygdala (Figure 6A). While the GM1d20:1-species was hardly visible within the hypothalamus and amygdala, GM1d18:1 showed a markedly higher expression within the amygdala. When quantified (Figure 6B), GM1d18:1 expression was eight times higher than GM1d20:1 expression in the amygdala (8.15 ± 0.29, n = 19), the highest ratio measured in any brain region analyzed (Figure 6C). This ratio is significantly higher than the ratio in the hypothalamus, where there was more than 6 times more GM1d18:1 than GM1d20:1 (6.40 ± 0.33, n = 18, Mann–Whitney test, p < 0.0001, Figure 6C).


Differential Anatomical Expression of Ganglioside GM1 Species Containing d18:1 or d20:1 Sphingosine Detected by MALDI Imaging Mass Spectrometry in Mature Rat Brain.

Weishaupt N, Caughlin S, Yeung KK, Whitehead SN - Front Neuroanat (2015)

Expression images of GM1d18:1 (green) and GM1d20:1 (red) showed relatively high GM1d18:1 expression within the amygdala, while GM1d20:1 expression was low within the hypothalamus and amygdala (A). Scale bar = 4 mm. A schematic cross section shows regions included in ROIs from which mass spectra were generated for the amygdala and hypothalamus (B). AHiAL, amygdalohippocampal area, anteriolateral part; BMP, basomedial amygdaloid nucleus, posterior part; BLP, basolateral amygdaloid nucleus, posterior part; DM, dorsomedial hypothalamic nucleus; MePD, medial amygdaloid nucleus, posterodorsal part; MePV, medial amygdaloid nucleus, posteroventral part; PeF, perifornical nucleus; PH, posterior hypothalamic nucleus; PLH, peduncular part of lateral hypothalamus; PMCo, posteromedial cortical amygdaloid nucleus; PMV, premammillary nucleus, ventral part; STiA, bed nucleus of the stria terminalis, amygdaloid division. The GM1d18:1/GM1d20:1 ratio was significantly higher within the amygdala than the hypothalamus (Mann–Whitney test, ∗∗∗∗p < 0.0001, C).
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Related In: Results  -  Collection

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Figure 6: Expression images of GM1d18:1 (green) and GM1d20:1 (red) showed relatively high GM1d18:1 expression within the amygdala, while GM1d20:1 expression was low within the hypothalamus and amygdala (A). Scale bar = 4 mm. A schematic cross section shows regions included in ROIs from which mass spectra were generated for the amygdala and hypothalamus (B). AHiAL, amygdalohippocampal area, anteriolateral part; BMP, basomedial amygdaloid nucleus, posterior part; BLP, basolateral amygdaloid nucleus, posterior part; DM, dorsomedial hypothalamic nucleus; MePD, medial amygdaloid nucleus, posterodorsal part; MePV, medial amygdaloid nucleus, posteroventral part; PeF, perifornical nucleus; PH, posterior hypothalamic nucleus; PLH, peduncular part of lateral hypothalamus; PMCo, posteromedial cortical amygdaloid nucleus; PMV, premammillary nucleus, ventral part; STiA, bed nucleus of the stria terminalis, amygdaloid division. The GM1d18:1/GM1d20:1 ratio was significantly higher within the amygdala than the hypothalamus (Mann–Whitney test, ∗∗∗∗p < 0.0001, C).
Mentions: Based on the relative expression of both GM1 species in molecular images, the hypothalamus had a relatively lower content of GM1 in comparison to the thalamus, the hippocampus, cortical regions and the amygdala (Figure 6A). While the GM1d20:1-species was hardly visible within the hypothalamus and amygdala, GM1d18:1 showed a markedly higher expression within the amygdala. When quantified (Figure 6B), GM1d18:1 expression was eight times higher than GM1d20:1 expression in the amygdala (8.15 ± 0.29, n = 19), the highest ratio measured in any brain region analyzed (Figure 6C). This ratio is significantly higher than the ratio in the hypothalamus, where there was more than 6 times more GM1d18:1 than GM1d20:1 (6.40 ± 0.33, n = 18, Mann–Whitney test, p < 0.0001, Figure 6C).

Bottom Line: Across layers of the sensory cortex, opposing expression gradients were found for GM1d18:1 and GM1d20:1.By far the highest GM1d18:1/d20:1 ratio was found in the amygdala.Differential expression of GM1 with d18:1- or d20:1-sphingosine bases in the adult rat brain suggests tight regulation of expression and points toward a distinct functional relevance for each of these GM1 species in neuronal processes.

View Article: PubMed Central - PubMed

Affiliation: Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, University of Western Ontario, London ON, Canada.

ABSTRACT
GM1 ganglioside plays a role in essential neuronal processes, including differentiation, survival, and signaling. Yet, little is known about GM1 species with different sphingosine bases, such as the most abundant species containing 18 carbon atoms in the sphingosine chain (GM1d18:1), and the less abundant containing 20 carbon atoms (GM1d20:1). While absent in the early fetal brain, GM1d20:1 continues to increase throughout pre- and postnatal development and into old age, raising questions about the functional relevance of the GM1d18:1 to GM1d20:1 ratio. Matrix-assisted laser desorption/ionization imaging mass spectrometry is a novel technology that allows differentiation between these two GM1 species and quantification of their expression within an anatomical context. Using this technology, we find GM1d18:1/d20:1 expression ratios are highly specific to defined anatomical brain regions in adult rats. Thus, the ratio was significantly different among different thalamic nuclei and between the corpus callosum and internal capsule. Differential GM1d18:1/GM1d20:1 ratios measured in hippocampal subregions in rat brain complement previous studies conducted in mice. Across layers of the sensory cortex, opposing expression gradients were found for GM1d18:1 and GM1d20:1. Superficial layers demonstrated lower GM1d18:1 and higher GM1d20:1 signal than other layers, while in deep layers GM1d18:1 expression was relatively high and GM1d20:1 expression low. By far the highest GM1d18:1/d20:1 ratio was found in the amygdala. Differential expression of GM1 with d18:1- or d20:1-sphingosine bases in the adult rat brain suggests tight regulation of expression and points toward a distinct functional relevance for each of these GM1 species in neuronal processes.

No MeSH data available.


Related in: MedlinePlus