Atorvastatin Protects NSC-34 Motor Neurons Against Oxidative Stress by Activating PI3K, ERK and Free Radical Scavenging

Abstract

Although statins, or hydroxymethylglutaryl coenzyme A (HMG-Co A) reductase inhibitors, are generally used to decrease levels of circulating cholesterol, they have also been reported to have neuroprotective effects through various mechanisms. However, recent results have indicated that they may be harmful in patients with amyotrophic lateral sclerosis (ALS). In this study, we investigate whether atorvastatin protects motor neuron-like cells (NSC-34D) from oxidative stress. To evaluate the effects of atorvastatin or hydrogen peroxide or both on NSC-34D cells, the cells were treated with various combinations of these agents. To evaluate the viability of the cells, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays and trypan blue staining were performed. Levels of free radicals and intracellular signaling proteins were evaluated using the fluorescent probe 2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA) and Western blotting, respectively. Atorvastatin protected NSC-34D cells against oxidative stress in a concentration-dependent manner. This neuroprotective effect of atorvastatin was blocked by LY294002, a phosphatidylinositol 3-kinase (PI3K) inhibitor and by FR180204, a selective extracellular signal-related kinase (ERK) inhibitor. Atorvastatin treatment increased the expression levels of p85αPI3K, phosphorylated Akt, phosphorylated glycogen synthase kinase-3β, phosphorylated ERK, and Bcl-2, which are proteins related to survival. Furthermore, atorvastatin decreased the levels of cytosolic cytochrome C, Bax, cleaved caspase-9, and cleaved caspase-3, which are associated with death in oxidative stress-injured NSC-34D cells. We conclude that atorvastatin has a protective effect against oxidative stress in motor neurons by activating the PI3K and ERK pathways as well as by scavenging free radicals. These findings indicate that statins could help protect motor neurons from oxidative stress.

Histaminergic transmission slows progression of amyotrophic lateral sclerosis

“…The levels of phosphorylated AKT in motor neurons are decreased in ALS patients and SOD1‐G93A mice . Known to exert a protective action on ALS neuronal cells, the up‐regulation of pAKT and pERK in the spinal cord of histidine‐treated SOD1‐G93A mice would thus suggest that the pro‐survival response sustained by histidine proceeds through activation of ERK and PI3K/AKT signalling. In agreement with this hypothesis, the neuroprotection of ALS motor neuron cells in vitro by histamine was dependent on AKT/ERK1/2 pathway activation, thus confirming previous results about the AKT/ERK1/2 pro‐survival axis in ALS motor neuron …”

Atorvastatin enhances kainate‐induced gamma oscillations in rat hippocampal slices

“…Pre‐treatment of PI3K inhibitor wortmannin prevent the enhancing effect of AT on γ oscillations, indicating that PI3K activation is required for the enhancement role of AT on γ. Post‐treatment of wortmannin counteracted AT's effect, suggesting that PI3K activation is involved in the maintenance of the enhanced γ by AT. These results are in agreement with the report that statins activating the PI3K/Akt pathway, promote synaptic plasticity (Jope et al ., ; Cespedes‐Rubio et al ., ; Lee et al ., ). Evidence in support of this supposition is also provided by the observation that PI3K activation improved learning (Enriquez‐Barreto et al ., ).…”

“…The role of ERK in the AT-induced c power enhancement Because AT was reported to activate ERK (Lee et al, 2015), we tested the effect of U0126, a highly selective inhibitor of ERK. U0126 (2.5 lΜ) was applied after the steady state of c oscillations was reached.…”

“…Statins render cortical neurons more resistant to NMDA-induced excitotoxicity (Zacco et al, 2003;Bosel et al, 2005), indicating a possible effect of AT through NMDARs. Extracellular signal-regulated kinase (ERK) and Phosphatidylinositol 3-kinase (PI3K) signaling are known to regulate synaptic plasticity (Kim et al, 2011), and can be activated by AT (Lee et al, 2015). Whereas ERK is necessary for NMDARs dependent LTP, a cellular model of learning and memory (Kanterewicz et al, 2000), PI3K mediates NMDAR dependent long-term depression and behavioral flexibility (Kim et al, 2011).…”

The role of PI3K/AKT pathway and its therapeutic possibility in Alzheimer's disease

“…In many stressful conditions, the pathway is inhibited and then it is involved in cell death. Describing in detail, ischemia in the brain and oxidative stress inhibit the PI3K/AKT pathway in neurons and neural stem cells and then induce cell death, so there have been a lot of studies to develop the way to protect neurons and neural stem cells by activating the pathway [10][11][12][13]. This phenomenon also happens in amyloid-induced cell death [14,15].…”