Neurites regrowth of cortical neurons by GSK3β inhibition independently of Nogo receptor 1

Abstract

J. Neurochem. (2010) 113, 1644–1658. Abstract Lesioned axons do not regenerate in the adult mammalian CNS, owing to the over‐expression of inhibitory molecules such as myelin‐derived proteins or chondroitin sulphate proteoglycans. In order to overcome axon inhibition, strategies based on extrinsic and intrinsic treatments have been developed. For myelin‐associated inhibition, blockage with NEP1–40, receptor bodies or IN‐1 antibodies has been used. In addition, endogenous blockage of cell signalling mechanisms induced by myelin‐associated proteins is a potential tool for overcoming axon inhibitory signals. We examined the participation of glycogen synthase kinase 3β (GSK3β) and extracellular‐related kinase (ERK) 1/2 in axon regeneration failure in lesioned cortical neurons. We also investigated whether pharmacological blockage of GSK3β and ERK1/2 activities facilitates regeneration after myelin‐directed inhibition in two models: (i) cerebellar granule cells and (ii) lesioned entorhino‐hippocampal pathway in slice cultures, and whether the regenerative effects are mediated by Nogo Receptor 1 (NgR1). We demonstrate that, in contrast to ERK1/2 inhibition, the pharmacological treatment of GSK3β inhibition strongly facilitated regrowth of cerebellar granule neurons over myelin independently of NgR1. Finally, these regenerative effects were corroborated in the lesioned entorhino‐hippocampal pathway in NgR1−/− mutant mice. These results provide new findings for the development of new assays and strategies to enhance axon regeneration in injured cortical connections.

CDK5 activator protein p25 preferentially binds and activates GSK3β

“…6), and was significantly worse than that induced by p25 plus CDK5. Consistent with previous findings (22,50), our data therefore suggests aberrant activity of GSK3β can also lead to loss of neurite arborization.…”

GSK-3 Inhibitors: Preclinical and Clinical Focus on CNS

“…In addition, SB-216763 was shown to inhibit axon growth in postnatal and embryonic DRG neurons (Owens et al, 2003; Alabed et al, 2011). On the other hand, different studies reported that SB-216763 induced the formation of multiple long axons in hippocampal, cerebellar granular (CG), and DRG neurons (Padilla et al, 1997; Jiang et al, 2005; Yoshimura et al, 2005; Seira et al, 2011). Furthermore, it improved axon regeneration in lesioned neurons (Seira et al, 2011).…”

Increased migration of olfactory ensheathing cells secreting the Nogo receptor ectodomain over inhibitory substrates and lesioned spinal cord

“…CSPG and OMgp proteins were purchased from R&D Systems (Minneapolis, MN, USA). Myelin extract was obtained as [40] and NogoA-containing membranes as [41].…”

“…Cells were placed in 24-well tissue culture dishes (Nunc, Roskilde, Denmark) on coated coverslips (see below) and grown for 24-48 h in DMEM medium supplemented with N2 and B27 (Invitrogen). The procedures were used to treat cells with MAIs or myelin; the cell surface was coated with purified myelin essentially as described [40]. In vitro experiment on microfluidic devices Embryonic cortical neurons were cultured in compartmented microchips (Cat.…”