Atorvastatin enhances neurite outgrowth in cortical neurons in vitro via up-regulating the Akt/mTOR and Akt/GSK-3β signaling pathways

Abstract

Aim: To investigate whether atorvastatin can promote formation of neurites in cultured cortical neurons and the signaling mechanisms responsible for this effect. Methods: Cultured rat cerebral cortical neurons were incubated with atorvastatin (0.05-10 μmol/L) for various lengths of time. For pharmacological experiments, inhibitors were added 30 min prior to addition of atorvastatin. Control cultures received a similar amount of DMSO. Following the treatment period, phase-contrast digital images were taken. Digital images of neurons were analyzed for total neurite branch length (TNBL), neurite number, terminal branch number, and soma area by SPOT Advanced Imaging software. After incubation with atorvastatin for 48 h, the levels of phosphorylated 3-phosphoinoside-dependent protein kinase-1 (PDK1), phospho-Akt, phosphorylated mammalian target of rapamycin (mTOR), phosphorylated 4E-binding protein 1 (4E-BP1), p70S6 kinase (p70S6K), and glycogen synthase kinase-3β (GSK-3β) in the cortical neurons were evaluated using Western blotting analyses. Results: Atorvastatin (0.05-10 µmol/L) resulted in dose-dependent increase in neurite number and length in these neurons. Pretreatment of the cortical neurons with phosphatidylinositol 3-kinase (PI3K) inhibitors LY294002 (30 µmol/L) and wortmannin (5 µmol/L), Akt inhibitor tricribine (1 µmol/L) or mTOR inhibitor rapamycin (100 nmol/L) blocked the atorvastatin-induced increase in neurite outgrowth, suggesting that atorvastatin promoted neurite outgrowth via activating the PI3K/Akt/mTOR signaling pathway. Atorvastatin (10 µmol/L) significantly increased the levels of phosphorylated PDK1, Akt and mTOR in the cortical neurons, which were prevented by LY294002 (30 µmol/L). Moreover, atorvastatin (10 µmol/L) stimulated the phosphorylation of 4E-BP1 and p70S6K, the substrates of mTOR, in the cortical neurons. In addition, atorvastatin (10 µmol/L) significantly increased the phosphorylated GSK-3β level in the cortical neurons, which was prevented by both LY294002 and tricribine. Conclusion: These results suggest that activation of both the PI3K/Akt/mTOR and Akt/GSK-3β signaling pathways is responsible for the atorvastatin-induced neurite outgrowth in cultured cortical neurons.

Atorvastatin prevents amyloid-β peptide oligomer-induced synaptotoxicity and memory dysfunction in rats through a p38 MAPK-dependent pathway

“…Primary cultures were obtained from the hippocampi of 0-to 24-h-old Sprague-Dawley rats as previously described [31] . The cultures were plated on poly-L-lysine-coated 16-mm-diameter coverslips (~150 cells/mm 2 ) for immunocytochemistry assays or 6-well culture plates (1×10 6 ) for Western blot analysis.…”

“…Western blot analysis were performed for the detection of synaptophysin, PSD-95, and p38MAPK, as previously described [31] . Fresh hippocampal tissue or cultured hippo-www.chinaphar.com Zhang LL et al Acta Pharmacologica Sinica npg campal neurons were lysed in RIPA buffer.…”

Atorvastatin prevents Aβ oligomer-induced neurotoxicity in cultured rat hippocampal neurons by inhibiting Tau cleavage

“…In our study, we found that atorvastatin pretreatment prevented AβO-induced decreases in Ser-9 phosphorylation in hippocampal neurons, suggesting decreased activity of GSK3β. Additionally, our previous study demonstrated that atorvastatin enhanced neuronal neurite outgrowth through up-regulation of the Akt/GSK3β signaling pathway [21] .…”

“…Hippocampal cultures were prepared from embryonic Sprague-Dawley rats as previously described [21] . The hippocampi of E18/19 rat fetuses were collected in Hanks' solution without Ca 2+ and Mg 2+ (D-Hanks).…”

Transcriptional and Epigenetic Regulation in Injury-Mediated Neuronal Dendritic Plasticity

“…Transcription factors are essential for the initiation of target gene transcription for the further production of transcription factors or the translation of other genes that play roles in the retraction, regrowth, and reorganization of dendritic branches [4][5][6]. Much of what we know about the roles transcription factors play in these processes stem from limited studies on the actions of a handful of key factors.…”