Astrocytes expressing GFP in 3D collagen gels provide an effective model for screening the glial response to potential CNS cell therapies

INTRODUCTION: Cell therapies hold promise for use in many CNS repair scenarios. A critical consideration in selecting cells suitable for implantation into the CNS is the extent of the host glial cell response. In particular, astrocytes can become reactive in response to the presence of non-CNS cells, undergoing proliferation and hypertrophy and contributing to the ‘glial scar’ and inhibition of neuronal regeneration [1,2]. Here we have developed a 3D culture system for screening the effect of potential therapeutic cells on astrocyte reactivity. This builds on previous work that developed 3D cultures to model reactive gliosis as assessed by immunodetection of astrocyte reactivity markers (such as glial fibrillary acidic protein, GFAP) over 15 days [3]. Here we use changes in astrocyte green fluorescent protein (GFP) volume as an early indicator of astrocyte hypertrophy, a key feature of reactive gliosis.