azd-6244 and Neurodegenerative-Diseases

Abnormal accumulation of acrolein, an α, β unsaturated aldehyde has been reported as one pathological cause of the CNS neurodegenerative diseases. In the present study, the neuroprotective effect of selumetinib (a MEK-ERK inhibitor) on acrolein-induced neurotoxicity was investigated in vitro using primary cultured cortical neurons. Incubation of acrolein consistently increased phosphorylated ERK levels. Co-treatment of selumetinib blocked acrolein-induced ERK phosphorylation. Furthermore, selumetinib reduced acrolein-induced increases in heme oxygenase-1 (a redox-regulated chaperone protein) and its transcriptional factor, Nrf-2 as well as FDP-lysine (acrolein-lysine adducts) and α-synuclein aggregation (a pathological biomarker of neurodegeneration). Morphologically, selumetinib attenuated acrolein-induced damage in neurite outgrowth, including neuritic beading and neurite discontinuation. Moreover, selumetinib prevented acrolein-induced programmed cell death via decreasing active caspase 3 (a hallmark of apoptosis) as well as RIP (receptor-interacting protein) 1 and RIP3 (biomarkers for necroptosis). In conclusion, our study showed that selumetinib inhibited acrolein-activated Nrf-2-HO-1 pathway, acrolein-induced protein conjugation and aggregation as well as damage in neurite outgrowth and cell death, suggesting that selumetinib, a MEK-ERK inhibitor, may be a potential neuroprotective agent against acrolein-induced neurotoxicity in the CNS neurodegenerative diseases.

Topics: Acrolein; alpha-Synuclein; Animals; Apoptosis; Benzimidazoles; Cells, Cultured; Cerebral Cortex; Humans; MAP Kinase Signaling System; Mitogen-Activated Protein Kinase Kinases; Necroptosis; Neurodegenerative Diseases; Neuronal Outgrowth; Neurons; Neuroprotective Agents; Primary Cell Culture; Protein Aggregates; Rats; Toxicity Tests, Acute

Clinically, high levels of acrolein (a highly reactive α, β-unsaturated aldehyde) and acrolein adducts are detected in the brain of patients with CNS neurodegenerative diseases, including Alzheimer's disease and spinal cord injury. Our previous study supports this notion by showing acrolein as a neurotoxin in a Parkinsonian animal model. In the present study, the effect of AZD6244 (an ATP non-competitive MEK1/2 inhibitor) on acrolein-induced neuroinflammation was investigated using BV-2 cells and primary cultured microglia. Our immunostaining study showed that lipopolysaccharide (LPS, an inflammation inducer as a positive control) increased co-localized immunoreactivities of phosphorylated ERK and ED-1 (a biomarker of activated microglia) in the treated BV-2 cells. Similar elevation in co-localized immunoreactivities of phosphorylated ERK and ED-1 was detected in the acrolein-treated BV-2 cells. Furthermore, Western blot assay showed increases in phosphorylated ERK in BV-2 cells subjected to LPS (1 μg/mL) or acrolein (30 μM); these increases were blocked by AZD6244 (10 μM). At the same time, AZD6244 attenuated LPS-induced TNF-α (a pro-inflammatory cytokine) and cyclooxygenase-II (COX II, a pro-inflammatory enzyme). Consistently, AZD6244 reduced acrolein-induced elevations in COX-II mRNA and COX-II protein expression. In addition, AZD6244 inhibited acrolein-induced increases in activated caspase 1 (a biomarker of inflammasome activation) and heme oxygenase-1 (a redox-regulated chaperone protein) in BV-2 cells. Using a transwell migration assay, AZD6244 attenuated acrolein (5 μM)-induced migration of BV-2 cells and primary cultured microglia. In conclusion, our study shows that acrolein is capable of inducing neuroinflammation which involved ERK activation in microglia. Furthermore, AZD6244 is capable of inhibiting acrolein-induced neuroinflammation. Our study suggests that ERK inhibition may be a neuroprotective target against acrolein-induced neuroinflammation in the CNS neurodegenerative diseases.

Topics: Animals; Anti-Inflammatory Agents; Astrocytes; Benzimidazoles; Cytokines; Inflammation; Lipopolysaccharides; Microglia; Neurodegenerative Diseases; NF-kappa B