Tetramethylpyrazine Promotes Migration of Neural Precursor Cells via Activating the Phosphatidylinositol 3-Kinase Pathway

Stem cell therapy may provide a novel therapeutic method for the replacement and regeneration of damaged neural cells in the central nervous system. However, insufficient stem cell migrating into the injured regions limits its applications. Although tetramethylpyrazine (TMP) originally isolated from Ligusticum walliichi (Chuanxiong) has been widely used to treat ischemic stroke in the clinic for many years because of its role in neuroprotection, how TMP impacts the migration of neural progenitor/precursor cells (NPCs) and what is the underlying cellular and molecular mechanism remain largely unknown. Here, we found that TMP promoted NPC migration through increasing the expression and secretion of stromal cell-derived factor 1 (SDF-1), a chemokine that has been well demonstrated to direct NPC cell trafficking, in a dose-dependent fashion as analyzed by using different methods. The role of TMP in NPC migration could be inhibited by AMD 3100, a chemokine (C-X-C motif) receptor 4 (CXCR4) antagonist. Further investigation of the molecular mechanisms revealed that TMP treatment rapidly activated phosphatidylinositol 3-kinase (PI3K)/Akt, protein kinase C (PKC), and extracellular signal-regulated kinase (ERK), but not Pyk2, in NPCs. NPC migration could be blocked by using pharmacological inhibitors for these signaling pathways such as LY294002 (a PI3K inhibitor), Myr-ψPKC (a PKC inhibitor), and an ERK1/2 inhibitor. Furthermore, TMP enhanced NPC migration toward the ischemic region in the MCAO rat model. Our findings provide mechanistic insights into the role of TMP in treating the neuropathological diseases, which suggest that TMP may be used as a potent drug for improving NPC migration in stem cell-based therapy.