Alpha-crystallin promotes rat olfactory ensheathing cells survival and proliferation through regulation of PI3K/Akt/mTOR signaling pathways

Transplantation of cultured olfactory ensheathing cells (OECs) into lesions can promote axonal regeneration. However, the acutely injured CNS environment affects the survival and proliferation of OECs which might impair its therapy effects. To investigate whether α-crystallin can promote the survival and proliferation of OECs, OECs were cultured with α-crystallin. The survival of OECs was assessed by counting the numbers of p75-labeled OECs. Cellular proliferative activity was estimated by flow cytometry and quantification of BrdU-labeled cells. Phosphorylated p85, Akt and mammalian target of rapamycin (mTOR) were detected when OECs were culture for 7 days. Our results showed that the numbers of p75-labeled or Brdu-labeled OECs in α-crystallin group were much more than that in control group. And α-crystallin increased the phosphorylation of both p85, Akt and mTOR. LY294002 abrogated the ability of α-crystallin to phosphorylate Akt and mTOR, and decreased the percentage of cells in S and G2/M stage which were treated with α-crystallin. These findings indicated that α-crystallin positively regulated the activation of PI3K/Akt/mTOR signaling pathway and promote the proliferation and survival of cultured OECs.