ERC-CoG-2016 – ID 724734- MINERVA
Microbiota-Gut-BraiN EngineeRed platform to eVAluate intestinal microflora impact on brain functionality

Brain neurodegeneration is a major challenge for todays’ research: Alzheimer’s disease is expected to reach 80 million patients worldwide in 2050 but still its main triggers are mostly unknown. Recently, many biologists, gastroenterologists, clinicians have proposed an intriguing CONCEPT referred as microbiota-gut-brain axis. It states that there is a connection between the brain, the gut and our intestinal microflora. Intestinal microflora is the group of microorganisms that live in our gut and that collectively named “microbiota”. Indeed, a huge amount of data indicates that microbiota affects brain functionality: in the last 8 years, more than 500 publications on this topic have been produced and 10 large projects have been already funded. In this context, a fascinating HYPOTESYS is attracting researchers attention: microbiota can trigger neurodegeneration trough the microbiota-gut-brain axis. Last year, the project “ AD-GUT”, funded in Horizon 2020 NMP call, proposed a new revolutionary therapeutic approach aimed at slowing down Alzheimer’s disease progression by modulating microbiota composition. So, WHY MINERVA? There is a GAP that keeps researchers far from fully clarify microbiota-neurodegeneration potential mechanisms: the lack of a comprehensive model of the microbiota-gut-brain axis able to bridge current in vivo model complexity with the in vitro tools simplicity. In MINERVA this gap will be targeted using an INNOVATIVE bioengineered APPROACH, exploring in a completely NEW way the relation between neurodegeneration and human intestinal microflora. MINERVA final GOAL is to develop the first engineered, validated multi-organ platform representing in vitro the connections among all the main players of the microbiota-gut-brain axis. The PLATFORM relies on three compartments, hosting sensorised microfluidic devices hydraulically connected and designed to fulfill the basic requirements of mass transport, fluid-dynamic parameters and sterility. In the “Microbiota-compartment”, human microbiota strains will be cultured and produce a mix of molecules named “secretome”. The secretome will be transported to the “Gut-compartment”, where human gut epithelial cells and cells from the immune system will modify it as occurs in vivo, giving the so called “metabolised secretome”. It will reach the “Brain-compartment”, the most innovative and complex part, that hosts a complete blood brain barrier model followed by two 3D human brain cell models, where neurons, astrocytes and microglia, the three main cellular populations of the brain, will be (a) co-cultured to explore microbiota effect on brain cells interconnected as in the real tissue and (b) cultured individually to investigate microbiota impact on each cell type. The team expertise, experience and its recent preliminary results will help in fulfilling MINERVA ambitious planning CHALLENGES: 1) to ensure an optimal proliferation of microbiota in anaerobic conditions, the same we have in our gut, 2) to develop two suitable hydrogels to simulate gut mucus that hosts microbiota in vivo and for 3D neural cell culturing; 3) to ensure an adequate oxygen and nutrients mass transport and 4) to accurately control the stress induced by the secretome that flows on the cells. Firstly, each device will be tested  individually to functionally VALIDATE the platform, monitoring hydraulic stability, mass transport, and cell behavior. Once all the main parameters can be stably controlled, the platform will be step-by-step fully assembled and validated. To biologically VALIDATE the platform, two of the main mechanisms involved in microbiota-neurodegeneration hypothesis will be addressed: the neuroimmune crosstalk and microbiota metabolites neurotoxicity. Brain cell models will be studied to known neurotoxins and detrimental microbiota strains: the platform will be considered validated once the same brain cell damage as reported in literature will be observed. At this point, Alzheimer disease neurodegeneration will be addressed in a more challenging scenario, investigating brain cell response once exposed to complete human microbiota from healthy donors and Alzheimer’s disease patients. MINERVA RESULTS are INNOVATIVE, as it is expected to deliver: 1) the first engineered, validated platform representing the microbiota-gut-brain axis; 2) three new engineered in vitro models of microbiota, gut and brain 3) two new 3D brain cell models and 4) new insights to clarify microbiota-neurodegeneration biochemical mechanism. MINERVA is BREAKTROUGH: its new bioengineering APPROACH might open the way to a completely new FIELD at the boundary between neuroscience and engineering where the investigation of neurodegeneration causes are shifted from the brain to the body periphery. MINERVA has a potential HUGE IMPACT: its INNOVATIVE PLATFORM, thanks to its VERSATILE design, might address microbiota impact and therapeutic potential on brain but also not-brain centered diseases. Finally, MINERVA represents by itself a major advancement in the field of multi-organ on chip devices but also in vitro brain disease models to explore new THERAPIES for Alzheimer’s and Parkinson’s disease.