From glia limitans to glial scars: in vitro co-culture studies of the astrocyte and meningeal interaction.

The brain-meninges interface, comprising of astrocytes and meningeal cells seperated by a shared basement membrane, plays critical roles in the central nervous system. Recent work has shown the importance of signalling between the brain and the meninges in neurodevelopment, health, disease, and in stem cell migration. Despite this recent research, the brain-meninges interface is significantly understudied. This systematic review evaluates 27 studies which examine astrocyte-meningeal cell co-culture models. The papers were identified from a search of PubMed, Scopus, and Web of Science and screened for eligibility according to the PRISMA guidelines. These papers utilized the astrocyte-meningeal cell co-culture to mimic different biological interfaces within the central nervous system such as the spinal cord, optic nerve, and the brain-meninges interface to examine various outcomes such as neurite outgrowth, morphology, glial scar formation, and protein expression. Our findings highlight significant gaps in our understanding of the brain-meninges interface, along with inconsistencies in methodologies when establishing the astrocyte-meningeal cell co-culture model. Finally, this review recommends a standardisation of methodologies for astrocyte-meningeal cell co-culture including model validation and detailed protocols. This will allow for improved understanding of these important interfaces in the brain.