Proof-of-Concept Human Organ-on-Chip Study: First Step of Platform to Assess Neuro-Immunological Communication Involved in Inflammatory Bowel Diseases.

Inflammatory bowel diseases (IBD) are complex chronic inflammatory disorders of the gastrointestinal (GI) tract. Recent evidence suggests that the gut-brain axis may be pivotal in gastrointestinal and neurological diseases, especially IBD. Here, we present the first proof of concept for a microfluidic technology to model bilateral neuro-immunological communication. We designed a device composed of three compartments with an asymmetric channel that allows the isolation of soma and neurites thanks to microchannels and creates an in vitro synaptic compartment. Human-induced pluripotent stem cell-derived cortical glutamatergic neurons were maintained in soma compartments for up to 21 days. We performed a localized addition of dendritic cells (MoDCs) to either the soma or synaptic compartment. The microfluidic device was coupled with microelectrode arrays (MEAs) to assess the impact on the electrophysiological activity of neurons while adding dendritic cells. Our data highlight that an electrophysiologic signal is transmitted between two compartments of glutamatergic neurons linked by synapses in a bottom-up way when soma is exposed to primed dendritic cells. In conclusion, our study authenticates communication between dendritic cells and neurons in inflammatory conditions such as IBD. This platform opens the way to complexification with gut components to reach a device for pharmacological compound screening by blocking the gut-brain axis at a mucosal level and may help patients.

Co-culture of Glutamatergic Neurons and Pediatric High-Grade Glioma Cells Into Microfluidic Devices to Assess Electrical Interactions.

Pediatric high-grade gliomas (pHGG) represent childhood and adolescent brain cancers that carry a rapid dismal prognosis. Since there is a need to overcome the resistance to current treatments and find a new way of cure, modeling the disease as close as possible in an in vitro setting to test new drugs and therapeutic procedures is highly demanding. Studying their fundamental pathobiological processes, including glutamatergic neuron hyperexcitability, will be a real advance in understanding interactions between the environmental brain and pHGG cells. Therefore, to recreate neurons/pHGG cell interactions, this work shows the development of a functional in vitro model co-culturing human-induced Pluripotent Stem (hiPS)-derived cortical glutamatergic neurons pHGG cells into compartmentalized microfluidic devices and a process to record their electrophysiological modifications. The first step was to differentiate and characterize human glutamatergic neurons. Secondly, the cells were cultured in microfluidic devices with pHGG derived cell lines. Brain microenvironment and neuronal activity were then included in this model to analyze the electrical impact of pHGG cells on these micro-environmental neurons. Electrophysiological recordings are coupled using multielectrode arrays (MEA) to these microfluidic devices to mimic physiological conditions and to record the electrical activity of the entire neural network. A significant increase in neuron excitability was underlined in the presence of tumor cells.

3D arrays of microcages by two-photon lithography for spatial organization of living cells.

This paper addresses a nanoengineering approach to create a fully three-dimensional (3D) network of living cells, providing an advanced solution to in vitro studies on either neuronal networks or artificial organs. The concept of our work relies on stackable scaffolds composed of microcontainers designed and dimensioned to favor the geometrically constrained growth of cells. The container geometry allows cells to communicate in the culture medium and freely grow their projections to form a 3D arrangement of living cells. Scaffolds are fabricated using two-photon polymerization of IP-L 780 photoresist and are coated with collagen. They are stacked by mechanical micromanipulation. Technical details of the proposed nanofabrication scheme and assembly of the modular culture environment are explained. Preliminary in vitro results using PC12 cells have shown that this structure provides a good basis for healthy cell growth for at least 16 days. Our approach is envisioned to provide tailor-made solutions of future 3D cell assemblies for potential applications in drug screening or creating artificial organs.