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Brain barriers training

Periodic Reporting for period 2 - BtRAIN (Brain barriers training)

Reporting period: 2017-09-01 to 2019-08-31

In their function to protect the nerve cells in the brain and spinal cord of the central nervous system (CNS) from toxic compounds, the brain barriers also block delivery of drugs to the CNS. This hinders proper diagnosis and effective treatment of many neurological disorders as diverse as Alzheimer’s disease, multiple sclerosis or brain tumors. The blood-brain barrier (BBB) is established by endothelial cells lining the wall of small CNS blood vessels. The blood-cerebrospinal fluid barrier (BCSFB) is established by epithelial cells of the choroid plexus, a structure protruding in the ventricles of the brain and producing the cerebrospinal fluid in which the entire brain is embedded and thus protected from physical impact. The high complexity of these brain barriers has severely hampered progress in the CNS therapeutic market.
BtRAIN has developed technologies allowing to i) predit in laboratory culture models the passing of drugs across the BBB, ii) in laobratory culture models to study the BBB under physiological flow conditions as they exist in the blood stream, iii) determine, which genes drive maturation of the brain barriers during embryonic development, iv) understand how the brain barriers change during ageing, and v) define novel therapeutic target structures on the brain barriers for therapeutic barrier stabilization in neurological disorders. For the scientific community BtRAIN has established a significant number of novel datasets allowing to search for genes expressed in the brain barriers during development health and disease. The BBBHub allows resarchers to explore the genes expressed in the brain barriers during development, health and disease. For the lay community BtRAIN has developed BrainBarriers4You diseeminating the knowledge created in BtRAIN to the public in the spoken languages in Europe.
BtRAIN has furthermore successfully educated a novel generation of young brain barriers researchers who have successfully pursued their research and created novel knowledge. BtRAIN ESRs have mastered to present and discuss their research data in international meetings and proven to be able to think out of the box and to bridge disciplinary interfaces. Their training across disciplines in addition to trainings in scientific communication, teachnology transfer and research management have shaped them to a highly skilled group of young researchers that created high visibility at the international brain barriers meetings. BtrAIN has thus succeeded to educate young researchers with a unique skillset who are able to work along the complete value creation chain in research and technological development.
BtRAIN employed a total of 12 ESRs with a different educational background. This interdisciplinary background was of fundamental importance The interdisciplinary background of the BtRAIN beneficiaries and the ESRs has provided the required skills and knowledge to successfully pursue pursue the research projects at hand.
Under Objective 1 BtRAIN has aimed to create and disseminate unique knowledge on characteristis of the brain barriers and how these change during development, agening and disease. To this end BtRAIN has established novel cell culture models of the brain barriers which allow for prediction if a specific drug can cross the BBB in the intact organism. Acccordingly BtRAIN has established culture models of the brain barrier better resembling the 3D situation in the live organism, e.g. exposing the cells to flow conditions mimicking the situation of the blood stream. These tissue culture models will now be suitable to mimic disease states of the BBB and investigate how this impacts on drug delivery or immune cell migration into the CNS. Furthermore, BtRAIN has established state-of-the art protocols for purifying brain barrier cells and methodologies allowing to isolate the molecule RNA as a readout for gene expression from these cells. High quality RNA is needed to perform the next-generation high throughput sequence analysis of the RNA molecules named „RNAseq”. Based on the number of copies found in the BBB one can determine, using modern bioinformatics tools, the precise profile of genes expressed at the brain barriers and their potential importance for regulating BBB specific mechanisms. BtRAIN has established a significant number of these novel RNAseq datasets, which are made available to the scientific community via the BBBHub, an online prlatform allowing to search these datasets. SOPs for the advanced protocols to purify brain barrier cells will be published accompanying the BBBHub. Making use of these datasets BtRAIN has found 77 conserved genes expressed in the BBB of vertebrates e.g. besides in man in zebrafish, mouse and rat that can thus be considered as “BBB signature”. In addition, BtRAIN found genes specifically expressed in the BBB in Alzheimer’s disease or during ageing in addition to genes expressed in the BCSFB of multiple sclerosis patients. Finally, BtRAIN was successful in defining and excluding novel therapeutic targets on the brain barriers suitable to influence immune cell trafficking across the brain barriers, stabilizing the brain barriers during neurological disorders and avoiding infection of the brain barriers.
Knowledge created in BtRAIN has been presented at many occasions at international meetings and has been published. A significant part of the knowledge created by BtRAIN will continue to be published in the near future. The RNAseq datasets are provided to the scientific community via the BBBHub in addition to the already available repositories.
The major progress beyond the state of the art achieved by the interdisciplinary work of BtRAIN is the development of the BBBHub and online platform designated to researchers allowing them to search for gene expression profiles of brain barriers provided by BtRAIN and in the future also by colleagues world-wide. BtRAIN realized that currently available datasets do not allow for comparative searches, e.g. metaanalyses as they lack the relevant information on the isolation of the brain barrier cells. BtRAIN has developed SOPs, which are forseen to be published in Fluids and Barriers of the CNS, the journal of the International Brain Barriers Society allowing for future improvement of the purification of brain barrier cells and preparation of additional datasets. In this context BtRAIN provides a novel searching tool and contributes to reducing the number of animal experiments according to the 3R rules.
BtRAIN has identified a number of novel drug targets on the brain barriers which are presently explored for their suitability to develop therapies for brain barrier stabilization or hinibition of immune cell trafficking or infections in neuroinflammation. Last but not least BtRAIN has established methodology allowing to explore if immune cells can carry drugs across the BBB.

Additional training of the ESRs in skills such as scientific communication have advanced their abilities in presenting their research to colleagues but also to lay people. This is exemplified by the ESR outreach activity, the homepage, where they explained the brain barriers and their research within BtRAIN to the lay public in their respective mother languages. BtRAIN has educated a group of young researchers with a unique professional skillset and the advantage of a strong network allowing them to pursue a successful career.