Thymus-expressed chemokine promotes survival of PC12 cells via PI3K pathway

Abstract

We reported previously that CCR9 was neuroprotective in the mouse hippocampal neurons. This study was aimed to investigate if thymus-expressed chemokine (TECK)/CCL25 could promote survival of PC12 cells though its receptor CCR9. pEGFP-N1/CCR9 recombinant was constructed and transfected into PC12 cells. Along with this, 50 nM NGF was used to induce PC12 cells to differentiate into sympathetic-like neurons. We show here that under serum-free conditions and within a concentration range (50-200 nM), TECK rescued pEGFP-N1/CCR9 transfected PC12 cells from undergoing apoptosis in serum-free medium; however, it did not exert a similar effect on the cells in the control. On the other hand, the PC12 cells succumbed to a higher concentration of TECK (≥ 300 nM). Bim expression was up-regulated in PC12 cells cultured in serum-free medium in the absence of factors or with anti-TECK+TECK; however, it was not up-regulated in TECK-treated PC12 cells. p-Akt was detected at 15 min which lasted for at least 60 min when PC12 cells were cultured in serum-free medium with TECK. Additionally, it was shown that such an effect was effectively blocked by PI3K inhibitor, Wortmannin. These data suggest that TECK promotes survival of serum-deprived PC12 cells through its receptor, CCR9, most likely via the PI3K/Akt signaling pathway.