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Biology subjects

Culot, M.

Publications and source records attributed to Culot, M..

2 recordsLinked to original sources

Lab-on-a-chip device integrating a human stem cell-based blood-brain barrier model with neural organoids for translational research

For advanced biomedical research, complex, well-described human blood-brain barrier (BBB) models are crucial for studying central nervous system pathologies and brain targeting of nanotherapeutics. Our aim was to establish and characterize a complex lab-on-a-chip (LOC) system integrating a BBB model with neural organoids (NO). We optimized the conditions for BBB-NO models under static and dynamic circumstances. The combination of a human stem cell-derived BBB co-culture model with human midbrain organoids in a microfluidic LOC allowed the observation of BBB and neural tissue changes and the separate analysis of the barrier and brain units. The LOC design enabled phase contrast and fluorescent microscopy on the whole brain endothelial culture surface, barrier integrity and permeability measurements across the BBB model, and molecule passage into NOs. BBB-specific endothelial morphology, gene and protein expression, and good barrier integrity were demonstrated, corroborating the strength of the LOC engineering and cellular design. The transport of targeted nanoparticles across the BBB model followed by their entry to neural organoids validated the barrier integrity and transporter functionality of the dynamic integrated complex model. As a proof-of-concept experiment to confirm the translational value of the BBB-NO model integrated in the LOC device, we examined a clinically used hyperosmolar iodinated contrast agent, iopamidol, with confirmed neurological side effects. We corroborated that iopamidol induces transient BBB dysfunction and neural effects in the complex system, not only validating the complex dynamic BBB-NO model but also pointing to the necessity to study BBB changes together with NO functions.

cell biology↗

Endothelial tight junctions and cell-matrix adhesions reciprocally control blood-brain barrier integrity

Brain endothelial cells (ECs) rely on mechanical cues to provide a physical barrier that protects the brain. Yet how ECs integrate forces to establish and maintain the blood-brain barrier (BBB) remains poorly understood. Here, we show that the two main endothelial force-bearing systems, tight junctions and cell-matrix adhesions, reciprocally control BBB integrity. Using a combination of super-resolution imaging and biophysical techniques, we reveal increasing mechanical loads on cell-cell junctions vs. cell-matrix adhesions in human stem cell-derived ECs during BBB maturation. This force redistribution is enabled by cytoskeletal remodeling, a compacted pattern of the tight junction protein claudin-5, and the emergence of specialised perinuclear cell-matrix adhesions. Mechanistically, we find an inverse relationship between claudin-5 levels and the expression of key cell-matrix adhesion proteins zyxin and vinculin in vitro and in mice. Finally, we demonstrate that this mechanobiological signature associated with BBB maturation is reversed upon BBB dysfunction after seizures in mice and in human patients with temporal lobe epilepsy. Collectively, our findings establish a novel interplay between mechanoresponsive elements in brain ECs, with implications for BBB stabilisation therapy in epilepsy.

neuroscience↗