Rat Astrocyte-Neuron Co-cultures versus purified co-cultured Astrocytes versus Astrocyte alone

Profiling of transcriptional changes in rat astrocytes when co-cultured with neurons: comparison of astrocytes cultured alone with astrocytes co-cultured with mouse hippocampal neurons. Co-cultured astrocytes are isolated using cold jet, a novel tool for these neuron-glia cultures. Over the last decade, the importance of astrocyte-neuron communication in neuronal development and synaptic plasticity has become increasingly clear. Since neuron-astrocyte interactions represent highly dynamic and reciprocal processes, we hypothesized that at least part of the involved astrocyte genes may be regulated as a consequence of their interactions with maturing neurons. In order to identify such neuron-induced astrocyte genes in vitro, we tested the effectiveness of the ‘cold jet’, a new method for separation of neurons from co-cultured astrocytes. The cold jet method is performed under ice-cold conditions and avoids protease-mediated isolation of astrocytes or time-consuming centrifugation, yielding intact astrocyte mRNA with approximately 90% of neuronal RNA removed. Using this method, we executed genome-wide profiling in which RNA derived from astrocyte-only cultures was compared with astrocyte RNA derived from differentiating neuron-astrocyte co-cultures. Data analysis revealed changes in expression of a large number of mRNAs and biological processes, including novel findings. Thus, cold jet is an efficient method to separate astrocytes from neurons in co-culture, and in this study reveals that neurons induce robust gene-expression changes in co-cultured astrocytes. Three-condition experiment, 1) Co-cultures neurons and astrocytes, vs. 2) Astrocytes from co-cultures purified by cold jet treatment, vs 3) Astrocyte alone with cold jet treatment. Two biological replicates per condition, each replicate derived from >3 independent samples.