Cellular localization of Y-box binding protein 1 in brain tissue of rats, macaques, and humans

Background: The Y-box binding protein 1 (YB-1) is considered to be
one of the key regulators of transcription and translation.
However, so far only limited knowledge exists regarding its
cellular distribution in the adult brain. Results: Analysis of YB-1
immunolabelling as well as double-labelling with the neuronal
marker NeuN in rat brain tissue revealed a predominant neuronal
expression in the dentate gyrus, the cornu ammonis pyramidal cell
layer, layer III of the piriform cortex as well as throughout all
layers of the parahippocampal cortex. In the hilus of the
hippocampus single neurons expressed YB-1. The neuronal expression
pattern was comparable in the hippocampus and parahippocampal
cortex of adult macaques and humans. Double-labelling of YB-1 with
the endothelial cell marker Glut-1, the multidrug transporter
P-glycoprotein, and the astrocytic marker GFAP did not indicate a
co-localization. Following status epilepticus in rats, no induction
of YB-1 occurred in brain capillary endothelial cells and neurons.
Conclusion: In conclusion, our study demonstrates that YB-1 is
predominantly expressed in neurons in the adult brain of rats,
macaques and humans. Lack of a co-localization with Glut-1 and
P-glycoprotein argues against a direct role of YB-1 in the
regulation of blood-brain barrier P-glycoprotein.