Evaluation of mitochondrial activity via cellular interactions between adrenal and neuronal cells in a microfluidic coculture device

Understanding the role of hypothalamic–pituitary–adrenal (HPA) axis is essential to mediate stress responses. Chronic activation of this axis leads to an overproduction of glucocorticoids, which is associated with neuronal damage and the development of psychiatric disorders. Despite the significance of these interactions, the mechanisms of cell-cell communication between adrenal and neuronal cells under HPA axis influence are not well understood. The investigation of the cellular interaction and corticosterone-induced mitochondrial damage, in a spatiotemporally controlled manner, remains a significant challenge. Here, we have developed an in vitro model using a microfluidic coculture system to simulate corticosterone-induced mitochondrial dysfunction. To our knowledge, there is few on-chip cellular models focused on this mitochondrial dysfunction. The microfluidic coculture device consists of two sets with control and experiment of thin interconnecting grooves that isolate heterogeneous cells spatially while allowing cellular communication through soluble factors. We have employed fluorescence molecules to visually characterize mass transport and investigated dynamic interactions between adrenal (Y1) and neuronal (HT-22) cells in a controlled microenvironment, mimicking key in vivo interactions. The results show that the activated adrenal cells trigger time-lapsed mitochondrial dysfunction in neuronal cells, damaging mitochondrial membrane potentials. The corticosterone-induced mitochondrial effects are confirmed on the chip, exhibiting asynchronous responses and decreased mitochondrial activity in individual neuronal cells upon exposure to authentic corticosterone in the stimulating chamber. Thus, the developed microfluidic coculture device offers a useful tool for real-time monitoring of intercellular mitochondrial response, elucidating complex cellular interactions underlying stress-related neurological dysfunctions, and holds potential for drug screening.