Background: Brain-derived neurotrophic factor (BDNF) plays a crucial role in promoting
survival and differentiation of neurons and neural stem cells (NSCs), but the downstream regulating
mechanisms remain poorly understood.
Objective: We investigated whether BDNF exerts its effect by triggering the phosphoinositide 3-kinase
(PI3K), protein kinase B, PKB (AKT), glycogen synthase kinase-3β (GSK-3β) and β-catenin signaling
pathway in cultured neurons and NSCs derived from the rat embryonic spinal cord.
Method: Immunocytochemistry was used to detect neuronal and NSCs characteristics. RT-PCR was
used to detect PI3K/AKT/GSK3β/β-catenin pathway expression.
Results: Neurons and NSCs were successfully separated and cultured from Sprague-Dawley rat embryonic
spinal cord and were respectively labeled using immunocytochemistry. Neuron-specific nuclear
protein, neuronal class III β-tubulin, and neurofilament expression were detected in neurons;
nestin, glial fibrillary acidic protein, microtubule-associated protein 2 and chondroitin sulfate glycosaminoglycan
expression were detected in the NSCs. BDNF promoted significant neuronal growth
(number, soma size, and average neurite length), as well as NSCs proliferation and differentiation, but
BDNF antibody decreased neuronal growth and NSCs proliferation and differentiation. RT-PCR was
used to detect changes in BDNF signal pathway components, showing that BDNF upregulated tropomyosin
receptor kinase B, phosphoinositide 3-kinase (PI3K), AKT and β-catenin, but downregulated
GSK-3β in the neurons and NSCs. BDNF antibody downregulated BDNF, tropomyosin receptor
kinase B, PI3K, AKT, β-catenin and cellular-myelocytomatosis viral oncogene, but upregulated GSK-
3β, in the neurons and NSCs.
Conclusion: Our findings suggested that BDNF contributed to neuronal growth and proliferation and
differentiation of NSCs in vitro by stimulating PI3K/AKT/GSK3β/β-catenin pathways.