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Free keywords:
NUCLEAR-LOCALIZATION, GLYCOGEN-PHOSPHORYLASE, CELL-PROLIFERATION,
AEROBIC GLYCOLYSIS, ENERGY-METABOLISM, TUMOR-CELLS, ALDOLASE-A,
RAT-BRAIN, PROTEIN, GLUTAMATEBehavioral Sciences; Neurosciences & Neurology; glycolysis, glycogen, nuclear localization, glutamine synthetase;
Abstract:
Astrocytes releasing glucose- and/or glycogen-derived lactate and
glutamine play a crucial role in shaping neuronal function and
plasticity. Little is known, however, how metabolic functions of
astrocytes, e.g., their ability to degrade glucosyl units, are affected
by the presence of neurons. To address this issue we carried out
experiments which demonstrated that co-culturing of rat hippocampal
astrocytes with neurons significantly elevates the level of mRNA and
protein for crucial enzymes of glycolysis (phosphofructokinase,
aldolase, and pyruvate kinase), glycogen metabolism (glycogen synthase
and glycogen phosphorylase), and glutamine synthetase in astrocytes.
Simultaneously, the decrease of the capability of neurons to metabolize
glucose and glutamine is observed. We provide evidence that neurons
alter the expression of astrocytic enzymes by secretion of as yet
unknown molecule(s) into the extracellular fluid. Moreover, our data
demonstrate that almost all studied enzymes may localize in astrocytic
nuclei and this localization is affected by the co-culturing with
neurons which also reduces proliferative activity of astrocytes. Our
results provide the first experimental evidence that the
astrocyte-neuron crosstalk substantially affects the expression of basal
metabolic enzymes in the both types of cells and influences their
subcellular localization in astrocytes. GLIA 2015;63:328-340
