Biology subjects

Goshi, N.

Publications and source records attributed to Goshi, N..

3 recordsLinked to original sources

bioRxiv2024

Rat primary cortical cell tri-culture to study effects of amyloid-beta on microglia function

IntroductionThe etiology and progression of sporadic Alzheimers Disease (AD) have been studied for decades. One proposed mechanism is that amyloid-beta (A{beta}) proteins induce neuroinflammation, synapse loss, and neuronal cell death. Microglia play an especially important role in A{beta} clearance, and alterations in microglial function due to aging or disease may result in A{beta} accumulation and deleterious effects on neuronal function. However, studying these complex factors in vivo, where numerous confounding processes exist, is challenging, and until recently, in vitro models have not allowed sustained culture of microglia, astrocytes and neurons in the same culture. Here, we employ a tri-culture model of rat primary neurons, astrocytes, and microglia and compare it to co-culture (neurons and astrocytes) and mono-culture enriched for microglia to study microglial function (i.e., motility and A{beta} clearance) and proteomic response to exogenous A{beta}. MethodsWe established cortical co-culture (neurons and astrocytes), tri-culture (neurons, astrocytes, and microglia), and mono-culture (microglia) from perinatal rat pups. On days in vitro (DIV) 7 - 14, the cultures were exposed to fluorescently-labeled A{beta} (FITC-A{beta}) particles for varying durations. Images were analyzed to determine the number of FITC-A{beta} particles after specific lengths of exposure. A group of cells were stained for {beta}III-tubulin, GFAP, and Iba1 for morphological analysis via quantitative fluorescence microscopy. Cytokine profiles from conditioned media were obtained. Live-cell imaging with images acquired every 5 minutes for 4 hours was employed to extract microglia motility parameters (e.g., Euclidean distance, migration speed, directionality ratio). Results and discussionFITC-A{beta} particles were more effectively cleared in the tri-culture compared to the co-culture. This was attributed to microglia engulfing FITC-A{beta} particles, as confirmed via epifluorescence and confocal microscopy. Adding FITC-A{beta} significantly increased the size of microglia, but had no significant effect on neuronal surface coverage or astrocyte size. Analysis of the cytokine profile upon FITC-A{beta} addition revealed a significant increase in proinflammatory cytokines (TNF-, IL-1, IL-1{beta}, IL-6) in tri-culture, but not co-culture. In addition, A{beta} addition altered microglia motility marked by swarming-like motion with decreased Euclidean distance yet unaltered speed. These results highlight the importance of cell-cell communication in microglia function (e.g., motility and A{beta} clearance) and the utility of the tri-culture model to further investigate microglia dysfunction in AD.

neuroscience↗

bioRxiv2022

Electrophysiological Activity of Primary Cortical Neuron-Glia Mixed Cultures

BackgroundWe have previously described a tri-culture of neurons, astrocytes, and microglia that accurately mimics the in vivo neuroinflammatory response (both neurotoxic and neuroprotective) to a wide range of neuroinflammatory stimuli. Electrophysiological activity is an essential measure of neuronal function, which is influenced by neuroinflammation. Microelectrode array (MEA) technology is a versatile tool to non-invasively study in vitro neural networks by simultaneously recording electrophysiological activity from multiple sites. In this study, we used extracellular recordings to determine the effect of microglia on neural network formation and stability in primary cortical cultures and monitor the changes in neural activity in response to neuroinflammatory stimuli. MethodsPrimary neonatal rat cortical tri-cultures of neurons, astrocytes, and microglia or co-cultures of neurons and astrocytes were cultured on custom MEAs and the neural activity was monitored for 21 days in vitro to assess culture maturation and network formation. Quantification of synaptic puncta and averaged spike waveforms were used to determine the difference in excitatory to inhibitory neuron ratio (E/I ratio) of the neurons in tri- and co-cultures. The electrophysiological response to lipopolysaccharide (LPS) treatment of both culture types were compared. ResultsThe tri- and co-culture showed minimal difference in electrophysiological markers of neural network formation and stability with the exception of a significant increase in spike frequency in the tri-culture at later timepoints (DIV 17 and 21). Additionally, there was no significant difference in the density of either post-synaptic or excitatory pre-synaptic puncta between the culture types. However, characterization of the average spike waveforms revealed that the tri-culture had an E/I ratio much closer to that found in the rat cortex. Finally, only the tri-culture displayed a significant decrease in both the number of active channels and spike frequency following LPS exposure. ConclusionsThis study demonstrates that the microglia in the tri-culture do not disrupt neural network formation and stability as quantified using extracellular recordings and may be a better representation of the in vivo cortex due to the closer E/I ratio than more traditional isolated neuron and neuron-astrocyte co-cultures. Additionally, the tri-culture is better able to mimic the neuroinflammatory response to LPS, which was quantified via changes in neural electrophysiological activity.

neuroscience↗

bioRxiv2020

A Primary Neural Cell Culture Model for Neuroinflammation

Interactions between neurons, astrocytes and microglia critically influence neuroinflammatory responses to insult in the central nervous system. Studying neuroinflammation in vitro has been difficult because most primary culture models do not include all three critical cell types. We describe an in vitro model of neuroinflammation comprised of neurons, astrocytes and microglia. Primary rat cortical cells were cultured in a serum-free medium used to co-culture neurons and astrocytes that is supplemented with three factors (IL-34, TGF-{beta} and cholesterol) used to support isolated microglia. This "tri-culture" can be maintained for at least 14 days in vitro while retaining a physiologically-relevant representation of all three cell types. Additionally, we demonstrate that the tri-culture system responds to lipopolysaccharide, mechanical trauma and excitotoxicity with both neurotoxic and neuroprotective aspects of the neuroinflammatory response observed in vivo. We expect the tri-culture model will enable mechanistic studies of neuroinflammation in vitro with enhanced physiological relevance.

neuroscience↗