Vitronectin regulates the axon specification of mouse cerebellar granule cell precursors via αvβ5 integrin in the differentiation stage

Vitronectin, an extracellular matrix protein, controls the differentiation of cerebellar granule cell precursors (CGCPs) via alpha v beta 5 integrin, particularly in the initial stage of differentiation to granule cells. In this study, we determined whether vitronectin regulates axon specification in this initial differentiation stage of CGCPs. First, we analyzed whether vitronectin deficiency, beta 5 integrin knockdown (KD), and beta 5 integrin overexpression affect axon specification of primary cultured CGCPs. Vitronectin deficiency and beta 5 integrin KD inhibited axon formation, while vitronectin administrated- and beta 5 integrin overexpressed-neurons formed multiple axons. Moreover, KD of beta 5 integrin suppressed vitronectin-induced multiple axon formation. These findings indicate that vitronectin contributes to regulating axon specification via alpha v beta 5 integrin in CGCPs. Next, we determined the signaling pathway involved in regulating vitronectin-induced axon specification. Wortmannin, an inhibitor of phosphatidylinositol 3-kinase (PI3K), inhibited vitronectin-induced multiple axon specification, and lithium chloride, an inhibitor of glyocogen synthase kinase 3 beta (GSK3 beta), attenuated the inhibitory effect of vitronectin-KO and beta 5 integrin KD on the specification of CGCPs. In addition, vitronectin induced the phosphorylation of protein kinase B (Akt) and GSK3 beta in neuroblastoma Neuro2a cells. Taken together, our results indicate that vitronectin plays an important factor in axon formation process in CGCPs via a beta 5 integrin/PI3K/GSK3 beta pathway.

Automated summary

The study demonstrates that vitronectin regulates axon specification in cerebellar granule cell precursors (CGCPs) through alpha v beta 5 integrin, with the involvement of beta 5 integrin and the PI3K/GSK3 beta pathway. Deficiency of vitronectin and knockdown of beta 5 integrin inhibit axon formation, while administration of vitronectin and overexpression of beta 5 integrin lead to multiple axon formation. These findings suggest that vitronectin plays a crucial role in axon formation in CGCPs.