Limits...
Metabolic consequences of interleukin-6 challenge in developing neurons and astroglia.

Brown JA, Sherrod SD, Goodwin CR, Brewer B, Yang L, Garbett KA, Li D, McLean JA, Wikswo JP, Mirnics K - J Neuroinflammation (2014)

Bottom Line: While several proteins have been identified as having some link to these developmental disorders, their prevalence is still small and their causative role, if any, is not well understood.Our results revealed that 1) the use of this technology, due to its superb media volume:cell volume ratio, is ideally suited for analysis of cell-type-specific exometabolome signatures; 2) developing neurons have low secretory activity at baseline, while astroglia show strong metabolic activity; 3) both neurons and astroglia respond to IL-6 exposure in a cell type-specific fashion; 4) the astroglial response to IL-6 stimulation is predominantly characterized by increased levels of metabolites, while neurons mostly depress their metabolic activity; and 5) disturbances in glycerophospholipid metabolism and tryptophan/kynurenine metabolite secretion are two putative mechanisms by which IL-6 affects the developing nervous system.Our findings are potentially critical for understanding the mechanism by which IL-6 disrupts brain function, and they provide information about the molecular cascade that links maternal immune activation to developmental brain disorders.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychiatry, 465 21st Avenue South, Vanderbilt University, Nashville, TN, 37232, USA. jacquelyn.a.brown@vanderbilt.edu.

ABSTRACT

Background: Maternal immune activation and subsequent interleukin-6 (IL-6) induction disrupt normal brain development and predispose the offspring to developing autism and schizophrenia. While several proteins have been identified as having some link to these developmental disorders, their prevalence is still small and their causative role, if any, is not well understood. However, understanding the metabolic consequences of environmental predisposing factors could shed light on disorders such as autism and schizophrenia.

Methods: To gain a better understanding of the metabolic consequences of IL-6 exposure on developing central nervous system (CNS) cells, we separately exposed developing neuron and astroglia cultures to IL-6 for 2 hours while collecting effluent from our gravity-fed microfluidic chambers. By coupling microfluidic technologies to ultra-performance liquid chromatography-ion mobility-mass spectrometry (UPLC-IM-MS), we were able to characterize the metabolic response of these CNS cells to a narrow window of IL-6 exposure.

Results: Our results revealed that 1) the use of this technology, due to its superb media volume:cell volume ratio, is ideally suited for analysis of cell-type-specific exometabolome signatures; 2) developing neurons have low secretory activity at baseline, while astroglia show strong metabolic activity; 3) both neurons and astroglia respond to IL-6 exposure in a cell type-specific fashion; 4) the astroglial response to IL-6 stimulation is predominantly characterized by increased levels of metabolites, while neurons mostly depress their metabolic activity; and 5) disturbances in glycerophospholipid metabolism and tryptophan/kynurenine metabolite secretion are two putative mechanisms by which IL-6 affects the developing nervous system.

Conclusions: Our findings are potentially critical for understanding the mechanism by which IL-6 disrupts brain function, and they provide information about the molecular cascade that links maternal immune activation to developmental brain disorders.

Show MeSH

Related in: MedlinePlus

Activation of glycerophospholipid metabolism in response to IL-6. (A) Numerous glycerophospholipid metabolites were significantly produced upon IL-6 exposure in both astrocytes and neuronal cultures. Three analytes were putatively identified as diacylglycerophosphocholine (m/z 732.55, ALR = 1.57, P <0.001), diacylglycerophospho-ethanolamine (m/z 768.56, ALR = 1.39, P <0.001), and n-methylethanolamine (m/z 156.04, ALR = 1.81, P <0 .001). Putative identifications were obtained by using mass measurement accuracy, retention time and confirmed based on fragmentation spectra [see Additional files 1, 2, 3, 4 and 5]. (B) Illustrates a simplified glycerophospholipid metabolism pathway and shows that n-methylethanolamine is a precursor metabolite to numerous developmentally important downstream metabolites.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
getmorefigures.php?uid=PMC4233071&req=5

Fig4: Activation of glycerophospholipid metabolism in response to IL-6. (A) Numerous glycerophospholipid metabolites were significantly produced upon IL-6 exposure in both astrocytes and neuronal cultures. Three analytes were putatively identified as diacylglycerophosphocholine (m/z 732.55, ALR = 1.57, P <0.001), diacylglycerophospho-ethanolamine (m/z 768.56, ALR = 1.39, P <0.001), and n-methylethanolamine (m/z 156.04, ALR = 1.81, P <0 .001). Putative identifications were obtained by using mass measurement accuracy, retention time and confirmed based on fragmentation spectra [see Additional files 1, 2, 3, 4 and 5]. (B) Illustrates a simplified glycerophospholipid metabolism pathway and shows that n-methylethanolamine is a precursor metabolite to numerous developmentally important downstream metabolites.

Mentions: From the prioritized list of metabolites altered by IL-6 exposure, we putatively identified three analytes (Figure 4A) that belong to the glycerophospholipid metabolism pathway (Figure 4B). The connection of this pathway to brain IL-6 activation has not previously been described. N-methylethanolamine phosphate was observed to be increased in the IL-6-exposed neurons (m/z = 156.065, RT = 314 s, ALR = 1.81, P <0.001) in comparison to the sham-treated neuronal cultures. Baseline levels of N-methylethanolamine phosphate were significantly higher in the glial cultures compared to those observed in the neuronal cultures. N-methylethanolamine phosphate can be produced through the transfer of a methyl group from S-adenosyl methionine to phophoethanolamine, catalyzed by phosphoethanolamine methyltransferase. This metabolite has an important biological role in glycerophospholipid metabolism and in development [37]. Importantly, the production of at least two other glycerophospholipid metabolites was detected in the secreted metabolome of IL-6 stimulated astroglia: diacylglycerophosphocholine (m/z = 732.551, RT = 216 s, ALR = 1.57, P <0.001) and diacylglycerophospho-ethanolamine (m/z = 768.564, RT = 124 s, ALR = 1.39, P <0.001). Glycerophosphocholines are the inactive form of long-chain polyunsaturated fatty acids (LCPUFAs), arachidonic acid (AA), docosahexaenoic acid (DHA), and eicosapentaenoic acid (EPA), and the disturbed metabolism of these species has been previously linked to schizophrenia, major depression, and bipolar disorder [38–42].Figure 4


Metabolic consequences of interleukin-6 challenge in developing neurons and astroglia.

Brown JA, Sherrod SD, Goodwin CR, Brewer B, Yang L, Garbett KA, Li D, McLean JA, Wikswo JP, Mirnics K - J Neuroinflammation (2014)

Activation of glycerophospholipid metabolism in response to IL-6. (A) Numerous glycerophospholipid metabolites were significantly produced upon IL-6 exposure in both astrocytes and neuronal cultures. Three analytes were putatively identified as diacylglycerophosphocholine (m/z 732.55, ALR = 1.57, P <0.001), diacylglycerophospho-ethanolamine (m/z 768.56, ALR = 1.39, P <0.001), and n-methylethanolamine (m/z 156.04, ALR = 1.81, P <0 .001). Putative identifications were obtained by using mass measurement accuracy, retention time and confirmed based on fragmentation spectra [see Additional files 1, 2, 3, 4 and 5]. (B) Illustrates a simplified glycerophospholipid metabolism pathway and shows that n-methylethanolamine is a precursor metabolite to numerous developmentally important downstream metabolites.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4233071&req=5

Fig4: Activation of glycerophospholipid metabolism in response to IL-6. (A) Numerous glycerophospholipid metabolites were significantly produced upon IL-6 exposure in both astrocytes and neuronal cultures. Three analytes were putatively identified as diacylglycerophosphocholine (m/z 732.55, ALR = 1.57, P <0.001), diacylglycerophospho-ethanolamine (m/z 768.56, ALR = 1.39, P <0.001), and n-methylethanolamine (m/z 156.04, ALR = 1.81, P <0 .001). Putative identifications were obtained by using mass measurement accuracy, retention time and confirmed based on fragmentation spectra [see Additional files 1, 2, 3, 4 and 5]. (B) Illustrates a simplified glycerophospholipid metabolism pathway and shows that n-methylethanolamine is a precursor metabolite to numerous developmentally important downstream metabolites.
Mentions: From the prioritized list of metabolites altered by IL-6 exposure, we putatively identified three analytes (Figure 4A) that belong to the glycerophospholipid metabolism pathway (Figure 4B). The connection of this pathway to brain IL-6 activation has not previously been described. N-methylethanolamine phosphate was observed to be increased in the IL-6-exposed neurons (m/z = 156.065, RT = 314 s, ALR = 1.81, P <0.001) in comparison to the sham-treated neuronal cultures. Baseline levels of N-methylethanolamine phosphate were significantly higher in the glial cultures compared to those observed in the neuronal cultures. N-methylethanolamine phosphate can be produced through the transfer of a methyl group from S-adenosyl methionine to phophoethanolamine, catalyzed by phosphoethanolamine methyltransferase. This metabolite has an important biological role in glycerophospholipid metabolism and in development [37]. Importantly, the production of at least two other glycerophospholipid metabolites was detected in the secreted metabolome of IL-6 stimulated astroglia: diacylglycerophosphocholine (m/z = 732.551, RT = 216 s, ALR = 1.57, P <0.001) and diacylglycerophospho-ethanolamine (m/z = 768.564, RT = 124 s, ALR = 1.39, P <0.001). Glycerophosphocholines are the inactive form of long-chain polyunsaturated fatty acids (LCPUFAs), arachidonic acid (AA), docosahexaenoic acid (DHA), and eicosapentaenoic acid (EPA), and the disturbed metabolism of these species has been previously linked to schizophrenia, major depression, and bipolar disorder [38–42].Figure 4

Bottom Line: While several proteins have been identified as having some link to these developmental disorders, their prevalence is still small and their causative role, if any, is not well understood.Our results revealed that 1) the use of this technology, due to its superb media volume:cell volume ratio, is ideally suited for analysis of cell-type-specific exometabolome signatures; 2) developing neurons have low secretory activity at baseline, while astroglia show strong metabolic activity; 3) both neurons and astroglia respond to IL-6 exposure in a cell type-specific fashion; 4) the astroglial response to IL-6 stimulation is predominantly characterized by increased levels of metabolites, while neurons mostly depress their metabolic activity; and 5) disturbances in glycerophospholipid metabolism and tryptophan/kynurenine metabolite secretion are two putative mechanisms by which IL-6 affects the developing nervous system.Our findings are potentially critical for understanding the mechanism by which IL-6 disrupts brain function, and they provide information about the molecular cascade that links maternal immune activation to developmental brain disorders.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychiatry, 465 21st Avenue South, Vanderbilt University, Nashville, TN, 37232, USA. jacquelyn.a.brown@vanderbilt.edu.

ABSTRACT

Background: Maternal immune activation and subsequent interleukin-6 (IL-6) induction disrupt normal brain development and predispose the offspring to developing autism and schizophrenia. While several proteins have been identified as having some link to these developmental disorders, their prevalence is still small and their causative role, if any, is not well understood. However, understanding the metabolic consequences of environmental predisposing factors could shed light on disorders such as autism and schizophrenia.

Methods: To gain a better understanding of the metabolic consequences of IL-6 exposure on developing central nervous system (CNS) cells, we separately exposed developing neuron and astroglia cultures to IL-6 for 2 hours while collecting effluent from our gravity-fed microfluidic chambers. By coupling microfluidic technologies to ultra-performance liquid chromatography-ion mobility-mass spectrometry (UPLC-IM-MS), we were able to characterize the metabolic response of these CNS cells to a narrow window of IL-6 exposure.

Results: Our results revealed that 1) the use of this technology, due to its superb media volume:cell volume ratio, is ideally suited for analysis of cell-type-specific exometabolome signatures; 2) developing neurons have low secretory activity at baseline, while astroglia show strong metabolic activity; 3) both neurons and astroglia respond to IL-6 exposure in a cell type-specific fashion; 4) the astroglial response to IL-6 stimulation is predominantly characterized by increased levels of metabolites, while neurons mostly depress their metabolic activity; and 5) disturbances in glycerophospholipid metabolism and tryptophan/kynurenine metabolite secretion are two putative mechanisms by which IL-6 affects the developing nervous system.

Conclusions: Our findings are potentially critical for understanding the mechanism by which IL-6 disrupts brain function, and they provide information about the molecular cascade that links maternal immune activation to developmental brain disorders.

Show MeSH
Related in: MedlinePlus