Neuronal glycosylation differentials in normal, injured and chondroitinase-treated environments

Abstract

Glycosylation is found ubiquitously throughout the central nervous system (CNS).Chondroitin sulphate proteoglycans (CSPGs) are a group of molecules heavily substituted with glycosaminoglycans (GAGs) and are found in the extracellular matrix (ECM) and cell surfaces. Upon CNS injury, a glial scar is formed, which is inhibitory for axon regeneration.Several CSPGs are upregulated within the glial scar, including NG2, and these CSPGs are key inhibitory molecules of axonal regeneration. Treatment with chondroitinase ABC (ChABC) can neutralise the inhibitory nature of NG2. A gene expression dataset was mined in silico to verify differentially regulated glycosylation-related genes in neurons after spinal cord injury and identify potential targets for further investigation. To establish the glycosylation differential of neurons that grow in a healthy, inhibitory and ChABC-treated environment, we established an indirect co-culture system where PC12 neurons were grown with primary astrocytes, Neu7 astrocytes (which overexpress NG2) and Neu7 astrocytes treated with ChABC. After 1, 4 and 8 days culture, lectin cytochemistry of the neurons was performed using five fluorescently-labelled lectins (ECA MAA, PNA, SNA-I and WFA).Usually α-(2,6)-linked sialylation scarcely occurs in the CNS but this motif was observed on the neurons in the injured environment only at day 8. Treatment with ChABC was successful in returning neuronal glycosylation to normal conditions at all timepoints for MAA, PNA and SNA-I staining, and by day 8 in the case of WFA. This study demonstrated neuronal cell surface glycosylation changes in an inhibitory environment and indicated a return to normal glycosylation after treatment with ChABC, which may be promising for identifying potential therapies for neuronal regeneration strategies.

Curcumin improves neural function after spinal cord injury by the joint inhibition of the intracellular and extracellular components of glial scar

“…Only targeting the intracellular IF protein could suppress the GFAP expression and reduce physical obstacles, but the newborn axons would stop growing once meeting the ECM [21,22]. Also, only inhibiting the extracellular CSPG expression may result in a fragile capacity of newborn axon growth, rendering them unable to pass through dense scar tissue and thus limiting neurologic recovery [23,24]. In our previous research, we reported that the use of antisense vimentin complementary DNA and chondroitinase ABC for treating SCI can effectively inhibit glial scar and shrink the cystic cavities area.…”

Unique glycosignature for intervertebral disc and articular cartilage cells and tissues in immaturity and maturity

“…SSEA-3 and -4 glycolipids used to identify human embryonic stem cells 23 24 . Cell surface glycosylation alters temporally and spatially during differentiation, development and disease 24 25 26 and reflects the cell phenotypic and tissue biological status 27 . Glycosylation has numerous biological roles, including cellular homing and trafficking, signalling, cell-cell and cell-ECM communication and adhesion 24 26 28 .…”

“…Cell surface glycosylation alters temporally and spatially during differentiation, development and disease 24 25 26 and reflects the cell phenotypic and tissue biological status 27 . Glycosylation has numerous biological roles, including cellular homing and trafficking, signalling, cell-cell and cell-ECM communication and adhesion 24 26 28 . Glycans exert their biological effects in vivo via lectins, carbohydrate-binding proteins 24 26 .…”

“…Glycosylation has numerous biological roles, including cellular homing and trafficking, signalling, cell-cell and cell-ECM communication and adhesion 24 26 28 . Glycans exert their biological effects in vivo via lectins, carbohydrate-binding proteins 24 26 . As glycan cell surface and ECM composition is altered depending on the tissue and cell type and its status, correct IVD ECM composition and cell health are inextricably linked.…”

Ex Vivo Rat Transected Spinal Cord Slices as a Model to Assess Lentiviral Vector Delivery of Neurotrophin-3 and Short Hairpin RNA against NG2

“…NG2 has been reported to be involved in inhibition of axonal regeneration after SCI [40][41][42]. The use of ChABC enzymes to digest the glycosaminoglycan chains of NG2 and related proteoglycans promoted neurite outgrowth and axonal growth [43][44][45][46]. Transduction with a lentiviral vector encoding ChABC has been shown to promote functional recovery in the forelimb post-SCI by reducing chondroitin sulphate chains and enhancing axonal growth after a cervical contusion injury [22].…”