Effects of pyrroloquinoline quinone on proliferation and expression of c-fos, c-jun, CREB and PCNA in cultured Schwann cells

Abstract

To investigate the effects of pyrroloquinoline quinine (PQQ) on proliferation and expression of c-fos, c-jun, CREB and PCNA in cultured Schwann cells. Schwann cells were cultured and purified in vitro. The purity of Schwann cells was identified by immunofluorescence of S-100. After synchronization of cell cycle by serum-free medium, different concentration of PQQ (0,1, 10, 100, 1,000, 10,000 nmol/L) were added into culture medium for 72 h. Flow cytometry was used to determine cell cycle. The content of c-fos, c-jun, and CREB mRNA were detected by RT-PCR, and the expression of PCNA protein was detected by Western blot. After PQQ treatment, the percentage of cells in G0/G1 phase decreased and the percentage of cells in S and G2/M phase increased. After treated by PQQ at concentration of 1-10,000nmol/L, content of c-fos,c-jun,CREB mRNA was increased by 0.33,0.42 and 0. 52 fold (P < 0. 05). However, at concentration of 1 000 nmol/L, there was no difference in mRNAs content when compare to control (P >0.05). And it showed a decline at concentration of 10,000 nmol/L (P < 0.05). PCNA protein expression was up-regulated at PQQ concentration of 1-100 nmol/L. At 100 nmol/L, the expression increased by 1.17 fold (P < 0.05); However, at 1,000 nmol/L, there was no difference in PCNA expression when compared to control. And 10,000 nmol/L of PQQ inhibited the expression of PCNA (P < 0.05). When treated with PQQ at concentration of 10-100 nmol/L, the proliferation of Schwann cells increased and the expression of c-fos,c-jun, CREB and PCNA was up-regulated.