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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

A schematic cross section shows the ROIs used to generate mass spectra for the corpus callosum (CC), which was also sampled in more anterior sections, and the internal capsule (IC, A). Mass spectrum from a representative section shows differential expression of GM1d18:1 And GM1d20:1 in the CC and IC (B). The GM1d18:1/GM1d20:1 ratio was significantly lower in the IC than in the CC (Mann–Whitney test, ∗∗∗∗p < 0.0001, C).
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Figure 3: A schematic cross section shows the ROIs used to generate mass spectra for the corpus callosum (CC), which was also sampled in more anterior sections, and the internal capsule (IC, A). Mass spectrum from a representative section shows differential expression of GM1d18:1 And GM1d20:1 in the CC and IC (B). The GM1d18:1/GM1d20:1 ratio was significantly lower in the IC than in the CC (Mann–Whitney test, ∗∗∗∗p < 0.0001, C).

Mentions: The expression ratio of the two GM1 species was measured in the corpus callosum (CC, Figure 3A) and in the internal capsule (IC, Figure 3A). GM1 signal was so low in the white matter relative to surrounding gray matter that meaningful images could not be generated, however, mass spectra clearly indicated the presence of both GM1d18:1 and GM1d20:1 within the sampled white matter regions (Figure 3B). The average ratio of all sampling areas per animal for the CC (5.506 ± 0.31, n = 19) was significantly higher than the ratio within the internal capsule (3.56 ± 0.22, n = 18, Mann–Whitney, p < 0.0001, Figure 3C).


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)

A schematic cross section shows the ROIs used to generate mass spectra for the corpus callosum (CC), which was also sampled in more anterior sections, and the internal capsule (IC, A). Mass spectrum from a representative section shows differential expression of GM1d18:1 And GM1d20:1 in the CC and IC (B). The GM1d18:1/GM1d20:1 ratio was significantly lower in the IC than in the CC (Mann–Whitney test, ∗∗∗∗p < 0.0001, C).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4664653&req=5

Figure 3: A schematic cross section shows the ROIs used to generate mass spectra for the corpus callosum (CC), which was also sampled in more anterior sections, and the internal capsule (IC, A). Mass spectrum from a representative section shows differential expression of GM1d18:1 And GM1d20:1 in the CC and IC (B). The GM1d18:1/GM1d20:1 ratio was significantly lower in the IC than in the CC (Mann–Whitney test, ∗∗∗∗p < 0.0001, C).
Mentions: The expression ratio of the two GM1 species was measured in the corpus callosum (CC, Figure 3A) and in the internal capsule (IC, Figure 3A). GM1 signal was so low in the white matter relative to surrounding gray matter that meaningful images could not be generated, however, mass spectra clearly indicated the presence of both GM1d18:1 and GM1d20:1 within the sampled white matter regions (Figure 3B). The average ratio of all sampling areas per animal for the CC (5.506 ± 0.31, n = 19) was significantly higher than the ratio within the internal capsule (3.56 ± 0.22, n = 18, Mann–Whitney, p < 0.0001, Figure 3C).

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