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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

Summary of quantification for all anatomical areas. Bar graph provides an overview of expression means for GM1d18:1/GM1d20:1 ratios across all regions measured (A). The GM1d18:1/GM1d20:1 expression ratio is color coded for all analyzed brain regions in schematic cross sections from anterior bregma (B) and posterior bregma (C).
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Figure 7: Summary of quantification for all anatomical areas. Bar graph provides an overview of expression means for GM1d18:1/GM1d20:1 ratios across all regions measured (A). The GM1d18:1/GM1d20:1 expression ratio is color coded for all analyzed brain regions in schematic cross sections from anterior bregma (B) and posterior bregma (C).

Mentions: Using MALDI IMS, we here report a wide variety of anatomically specific expression ratios of GM1d18:1/GM1d20:1 (Figure 7), which likewise points toward a differential functional role of these lipid species. When interpreting mass spectrometric data from imaged regions, one should be mindful that GM1 ganglioside is preferentially incorporated into lipid rafts, and therefore the overall measured ratios in each anatomical region include synaptic GM1. Pre-synaptic GM1 may be expressed by projection neurons from remote brain areas that synapse with resident neurons, and post-synaptic GM1 may include dendrites from neighboring neurons that reach into the ROI where the GM1 ratio was measured. Therefore, the GM1d18:1/GM1d20:1 ratio measured in these areas does not necessarily reflect the expression profile of resident neurons.


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)

Summary of quantification for all anatomical areas. Bar graph provides an overview of expression means for GM1d18:1/GM1d20:1 ratios across all regions measured (A). The GM1d18:1/GM1d20:1 expression ratio is color coded for all analyzed brain regions in schematic cross sections from anterior bregma (B) and posterior bregma (C).
© Copyright Policy
Related In: Results  -  Collection

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

Figure 7: Summary of quantification for all anatomical areas. Bar graph provides an overview of expression means for GM1d18:1/GM1d20:1 ratios across all regions measured (A). The GM1d18:1/GM1d20:1 expression ratio is color coded for all analyzed brain regions in schematic cross sections from anterior bregma (B) and posterior bregma (C).
Mentions: Using MALDI IMS, we here report a wide variety of anatomically specific expression ratios of GM1d18:1/GM1d20:1 (Figure 7), which likewise points toward a differential functional role of these lipid species. When interpreting mass spectrometric data from imaged regions, one should be mindful that GM1 ganglioside is preferentially incorporated into lipid rafts, and therefore the overall measured ratios in each anatomical region include synaptic GM1. Pre-synaptic GM1 may be expressed by projection neurons from remote brain areas that synapse with resident neurons, and post-synaptic GM1 may include dendrites from neighboring neurons that reach into the ROI where the GM1 ratio was measured. Therefore, the GM1d18:1/GM1d20:1 ratio measured in these areas does not necessarily reflect the expression profile of resident neurons.

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