Mimicking in-vitro endothelial and epithelial barriers of the central nervous system to study permeability and transcytosis using precision nanomedicines.

Group: Nanobioengineering and Molecular Bionics
Group leader: Josep Samitier (jsamitier@ibecbarcelona.eu) and Giuseppe Battaglia (gbattaglia@ibecbarcelona.eu).

Research project

Understand the molecular mechanisms of transport from and to in the central nervous system (CNS) is a key factor in the pathogenesis and progression of many neurological diseases including Alzhmeir, Parkinson, several dementias, and brain tumours. The tailored permeability control of the barriers is a critical therapeutic target to enable efficient drug delivery or to re-establish the restricted molecules transport modified by the disease.  However, the existing knowledge of CNS barriers and their ability to interface with the CNS cells creating neuro-vascular units (NVU) is poor understood and the experimental analysis using animals or in vitro models is far to mimics the CNS human characteristics.

This project is focused in the development of 3D barrier-interface of CNS models to mimic in vitro the physiological behaviour and their relationship with relevant neuropathological diseases. We will develop a new smart Micro Physiological Systems to analyse the molecular phenomena involved in the endothelial BBB/BSCB barriers and epithelial BCSFB barrier, combining new 3D printing microfluidic technologies with 3D cell coculture and sensor integration for in situ stimulus and recording.  Our approach combines the development of specifics scaffolds (mainly composite hydrogels) with specific nanopattern of adhesion proteins to tailor the 3D cell co-culture necessary for the blood-CNS barriers.

Specific objectives

  • Simulation, design and fabrication of Microfluid platform for interface barrier studies
  • Use of modified photolithographic polymers composition for microfluid 3D printing improvement.
  • Development of human neurovascular units. Analysis of parameters as cell density and specific biomarkers involved in the tight junction’s physiology.
  • Shedding light on vesicular transports (also transcytosis) using specific markers to highlight tubular carriers and their rate of fission and fusion from apical to basal and vice versa.
  • Development of epithelial-CNS barriers. Analysis of parameters as cell density and specific biomarkers involved in the tight junction’s physiology.
  • Comparison between endothelial and epithelial transcytosis using precision nanomedicines.
  • A systematic study of the barrier permeability and tight junctions’
  • Simulate the physiological environment of pathological CNS Barriers alterations including glioma and inflammation.

Job position

The aim is to develop 3D cell cultures in microfluidic devices to mimic the barrier/interface complex system to predict efficiently and in a fast and reproducible way drug penetration and mimic dynamic neurological disease models. The combination with 3Dbioprinting to introduce 3D self-organized microvascular endothelial cells will allow us to mimic the configuration of different CNS barriers including the choroidal plexus villi. We will use primary dural fibroblast cells derived from patients, reprogrammed into induced pluripotent stem cellsiPS and differentiated into all the components.

Interendothelial junctions are mainly composed by adhering (AJs), tight (TJs), and gap junctions (GJs). In BBB and BSCB blood-neural barriers, TJs are predominant forming extensive networks at the apical side of interendothelial junctions, which limit the permeation (passive transport) of ions and hydrophilic molecules by size exclusion. Meanwhile, active transport across the blood-neural barriers is regulated by membrane transporters and vesicular mechanisms. A decreased expression of TJ-associated proteins ZO-1 and occludin, and of adhering junctions’ proteins (VE)-cadherin and β-catenin has been reported for spinal cord micro vessels and cultured spinal cord endothelial cells with respect to cultured brain microvasculature endothelial cells. In addition we have indentified a tubular transporter that allows fast shuttling of large macromolecules and nanoparticles across the endothelial layer, we will create ad hoc genetic modification to introduce fluorescent markers to monitor in real time crossing using advanced light sheet (LS) and stimulated emission depletion (STED) microscopy.

The objective  is to study inter-endothelial mechanisms by high resolution optical microscopy and how we can modulate the expression of the different proteins involved modifying gradients of chemical cues induced by the extracellular matrix or the presence of different densities of cells as pericytes or astrocytes in the different regions of the CNS. We will map out these profiles with the transport mechanisms indentyfing the different receptors involved with fast transcytosis.