Picture a lively triad: Glia, neurons, and inflammation. They each have their own role in the brain, but how do they interact? Researchers developed a new model, like a complex dance between performers, to study the communication between glia and neurons. By adding exogenous microglia to a culture medium, they created a triculture system that closely resembles the brain’s cellular composition. They confirmed the presence of the intended cell types using immunocytochemistry. As more microglia were added, the number of ramified microglia decreased. Multi-electrode array recordings showed that microglia suppress neuronal activity in a dose-dependent manner. The triculture model also revealed changes in dendritic spines and synaptic protein densities, suggesting that microglia directly or indirectly affect synapse function. This innovative model provides a more accurate representation of glia-neuron interactions compared to traditional cocultures. Its potential for drug discovery and understanding neurodegenerative diseases is exciting! Dive into this fascinating research for more details.

Neuroinflammation and hyperexcitability have been implicated in the pathogenesis of neurodegenerative disease, and new models are required to investigate the cellular crosstalk involved in these processes. We developed an approach to generate a quantitative and reproducible triculture system that is suitable for pharmacological studies. While primary rat cells were previously grown in a coculture medium formulated to support only neurons and astrocytes, we now optimised a protocol to generate tricultures containing neurons, astrocytes and microglia by culturing in a medium designed to support all three cell types and adding exogenous microglia to cocultures. Immunocytochemistry was used to confirm the intended cell types were present. The percentage of ramified microglia in the tricultures decreases as the number of microglia present increases. Multi-electrode array recordings indicate that microglia in the triculture model suppress neuronal activity in a dose-dependent manner. Neurons in both cocultures and tricultures are responsive to the potassium channel blocker 4-aminopyridine, suggesting that neurons remained viable and functional in the triculture model. Furthermore, suppressed neuronal activity in tricultures correlates with decreased densities of dendritic spines and of the postsynaptic protein Homer1 along dendrites, indicative of a direct or indirect effect of microglia on synapse function. We thus present a functional triculture model, which, due to its more complete cellular composition, is a more relevant model than standard cocultures. The model can be used to probe glia-neuron interactions and subsequently aid the development of assays for drug discovery, using neuronal excitability as a functional endpoint.

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