SYN3D: Explorar o papel das forças biomecânicas na formação de sinapses como uma estratégia para combater a neurodegeneração

Understanding how synapses are made is not only a pressing issue in cellular neuroscience but also an incredible route to explore therapeutic strategies designed to increase synapse formation in mature neurons, during healthy aging or in disease. The main objective of SYN3D is to understand and predict how new synaptic boutons are formed within established neural circuits, considering the 3D microenvironment to which neurons are exposed, including other cell types (see graphical abstract). We hypothesize that knowing the factors that favor synapse formation in neuronal circuits can be used as a strategy to improve neuronal function and activity in the diseased brain, namely in neurodegenerative disorders where there is a notable loss of synapses. To tackle this problem, we divided the project in the following two interconnected main objectives: 1. To make use of the extensive genetic toolkit and imaging accessibility of Drosophila to use this model as an in vivo platform to assess the contribution of biophysical and biochemical factors for synapse formation in wired neurons (Tasks 1-3). In particular, we aim to address the roles that the extracellular matrix composition and other cells in located in the vicinity of neurons and their synapses plays on neuronal morphology and plasticity. Then we will dissect the downstream intracellular signalling pathways regulated by biomechanical factors. Specifically: Task 1. Neuronal extrinsic factors: Impact of extracellular matrix composition on synaptic formation Task 2. Neuronal extrinsic factors: effect of mechanical compression by muscle and glia cells on synapse formation Task 3. Neuronal intrinsic factors: signaling mechanism and genetic pathway for bouton formation by blebbing To develop a human-derived 3D multicellular system to assess and manipulate synapse formation (Tasks 4-5). Task 4. Human-derived neurospheroids: establishment of a 3D-platform to manipulate synapse formation in a complex human-derived system. Task 5. Mimicking human brain: setup a multicellular matrix system with different substrate stiffness to study and manipulate human synapses We expect that using the powerful genetics and in vivo imaging potential of Drosophila will allow the identification of the principles that guide synaptic bouton addition to wired neurons, considering their 3D microenvironment. By pairing these studies with human-derived neurospheroids, we will develop a new controlled multicellular matrix system to mimic the brain environment. We will use bioreactor-based and biopolymer-based culture systems because they offer distinct advantages: bioreactors offer a more physiologically environment with enhanced control over culture conditions, while biopolymer matrices provide stable scaffolds with tunable properties11,12. Together, it will allow us to test the contribution of ECM stiffness and of cellular biomechanical properties to synapse formation. SYN3D aims to address a critical challenge of neurodegenerative disorders, how to compensate synapse loss if neurons are already lost by the time of diagnosis. The focus on synaptic growth and rewiring, offers a unique perspective that diverges from traditional approaches centered on the genetics of each disease. Overall, we trust that SYN3D, and its multidisciplinary team, represents an innovative project that promises to push the boundaries of current knowledge and significantly impact both research and clinical practice in neuroscience.