Immobilization of chondroitinase ABC-I and -II on chitosan microbeads improve neurite growth in CSPG-enriched astrocyte culture

Abstract

Chondroitin sulfate proteoglycans (CSPGs) are extra-cellular matrix molecules that are upregulated at lesion site restricting axonal regrowth after spinal cord injury. Recombinant chondroitinase ABC I and II (ChABC-I & -II) enhance prospects of axonal regrowth through the lesion by cleaving CS moieties of the PGs. We attempted to immobilize ChABC-I or -II separately on chitosan microbeads using glutaric dialdehyde to reduce ChABC activity decay in vivo. Immobilized ChABC-I demonstrated CS-cleaving activity both in biochemical assay and in CSPGs-enriched astrocyte cultures that had been activated by transforming growth factor beta (TGF-β). Neurite length was increased in co-cultures of TGF-!b activated astrocytes and cortical neurons mixed with immobilized ChABC-I or immobilized ChABC-II. Given CSPG enrichment at astrocyte-Schwann cell (A/S) encounters, A/S confrontation co-culture was used in a further bioassay of immobilized enzyme activity. Preliminary data showed that neurite length was increased in ChABC-I treated A/S co-culture. In future, the effect of immobilized ChABC-I and -II on neurite length will be tested in A/S co-culture.