The mechanisms of EGFR in the regulation of axon regeneration.

ABSTRACT

To understand the relationship between epidermal growth factor receptor (EGFR) and axon regeneration and the mechanisms of how EGFR regulates the neuronal intrinsic regenerative ability, we evaluated the levels of mRNA and protein of EGFR、total mammalian target of rapamycin (mTOR), p-mTOR(Ser2448) , total Akt and p-Akt(Ser473) in rats of different developmental stage by using Western blot and real-time polymerase chain reaction analysis. Axon protein tau and neuron proteins ß-tubulin/neurofilament (NF) were assessed to evaluate the extent of the axon regeneration in cultured neuron cells. Expressions of EGFR、total mTOR, p-mTOR(Ser2448) , total Akt and p-Akt(Ser473) in cultured neuron cells were also detected using Western blot analysis. Our results showed that the expressions of EGFR and mTOR dropped off with the ageing of the rats, and Ser473 phosphorylation of Akt and Ser2448 phosphorylation of mTOR were highly expressed in foetal and newborn rats but decreased obviously in adult rats. tau, ß-tubulin and NF were upregulated when EGFR was overexpressed and down-regulated after EGFR was blocked. The phosphorylation of mTOR and Akt was apparently elevated when EGFR was overexpressed and decreased when EGFR was blocked, which suggested that EGFR has the potential to regulate the neuronal intrinsic regeneration and mTOR and PI3K/Akt pathway activation may have an important role in it.