LIMK1 is Involved in the Protective Effects of Bone Morphogenetic Protein 6 Against Amyloid-β-Induced Neurotoxicity in Rat Hippocampal Neurons

Bone morphogenetic protein 6 (BMP6) has neuroprotective effects against various neuronal injuries, but its effect on amyloid-β (Aβ)-induced neurotoxicity remains unclear. We exposed rat hippocampal neurons to different concentrations of Aβ_25-35 to induce neurotoxicity, and then treated cells with BMP6 to assess the neuroprotective effects. In vivo, we bilaterally injected Aβ_1-40 into basal forebrain to simulate the neuropathological process of Alzheimer's disease (AD), and explored changes in the expression of BMP6 and LIMK1. Our data demonstrated that BMP6 prevented apoptosis induced by a high dose of Aβ_25-35, and inhibited rod formation induced by low dose of Aβ_25-35 in hippocampal neurons. Forebrain injection of Aβ_1-40 led to a significant downregulation of BMP6, and inactivation of LIMK1 pathway in basal forebrain, whereas the opposite changes were observed in hippocampus. Our results suggest that BMP6 has neuroprotective effects against Aβ_25-35. The BMP6 and LIMK1 pathways may have different expression patterns at different stages of AD, and be self-regulating via a negative feedback mechanism between different brain regions.