CTX TNA2

CTX-TNA2 is an immortalized type I astrocyte cell line derived from primary cultures of astrocytes from the frontal cortex of 1-day-old Sprague-Dawley rat pups. After three days in primary culture, cells were transfected with an SV40 large T antigen expression construct under the control of a human GFAP promoter and murine PGK-neo promoter. Clonal expansion under G418 selection produced a stable cell line in which >95% of cells express the SV40 T antigen. Immortalized CTX-TNA2 cells maintain many of the phenotypic and biochemical properties characteristic of astrocytes.

Morphologically, the cells are polygonal or spindle-shaped. About 20% of the cells in culture are immunoreactive for GFAP, a major marker of astrocytes. Functionally, CTX-TNA2 cells synthesize α₂-macroglobulin at levels similar to primary astrocytes and have a β-alanine-inhibitable high affinity uptake system for GABA. They also lack markers characteristic of type II astrocytes and do not synthesize proenkephalin A or galactocerebroside. The above properties make CTX-TNA2 a convenient in vitro model of type I astrocytes.

CTX-TNA2 is widely used in neuroscience research to model aspects of glial biology, mechanisms of neurotoxicity, and neuroprotection. They have been used to construct functional in vitro blood-brain barrier (BBB) models in co-culture with brain endothelial cells with resultant high transendothelial electrical resistance and expression of tight junction proteins, efflux transporter activity, and receptor-mediated transferrin uptake. CTX-TNA2 also provides a stable and reproducible in vitro model for the study of oxidative stress responses, mitochondrial dysfunction, excitotoxicity-induced apoptosis and autophagy, and other astrocyte-mediated mechanisms of relevance to neurodegenerative disease and brain injury.