Synapto-Protective Drugs Evaluation in Reconstructed Neuronal Network

Abstract

Chronic neurodegenerative syndromes such as Alzheimer’s and Parkinson’s diseases, or acute syndromes such as ischemic stroke or traumatic brain injuries are characterized by early synaptic collapse which precedes axonal and neuronal cell body degeneration and promotes early cognitive impairment in patients. Until now, neuroprotective strategies have failed to impede the progression of neurodegenerative syndromes. Drugs preventing the loss of cell body do not prevent the cognitive decline, probably because they lack synapto-protective effects. The absence of physiologically realistic neuronal network models which can be easily handled has hindered the development of synapto-protective drugs suitable for therapies. Here we describe a new microfluidic platform which makes it possible to study the consequences of axonal trauma of reconstructed oriented mouse neuronal networks. Each neuronal population and sub-compartment can be chemically addressed individually. The somatic, mid axon, presynaptic and postsynaptic effects of local pathological stresses or putative protective molecules can thus be evaluated with the help of this versatile “brain on chip” platform. We show that presynaptic loss is the earliest event observed following axotomy of cortical fibers, before any sign of axonal fragmentation or post-synaptic spine alteration. This platform can be used to screen and evaluate the synapto-protective potential of several drugs. For instance, NAD+ and the Rho-kinase inhibitor Y27632 can efficiently prevent synaptic disconnection, whereas the broad-spectrum caspase inhibitor zVAD-fmk and the stilbenoid resveratrol do not prevent presynaptic degeneration. Hence, this platform is a promising tool for fundamental research in the field of developmental and neurodegenerative neurosciences, and also offers the opportunity to set up pharmacological screening of axon-protective and synapto-protective drugs.

A viral peptide that targets mitochondria protects against neuronal degeneration in models of Parkinson’s disease

“…Consistent with our previous findings [18][19][20] , we observed that direct somatic application of rotenone, a mitochondria complex I targeting toxin, led to rapid (o4 h) and massive cell death and axonal degeneration, which was moderately but consistently reduced by BDV infection ( Supplementary Fig. 1).…”

Manipulation of the N‐terminal sequence of the Borna disease virus X protein improves its mitochondrial targeting and neuroprotective potential

“…To assess the neuroprotective potential of X mutant proteins, we used oriented primary neuronal cultures grown in microfluidic devices, which permit the strict physical separation and fluidic isolation of the somatodendritic and axonal compartments. This culture setup allows for modeling the dying‐back pattern of neurodegeneration in response to direct axonal insult and has been used extensively to demonstrate the neuroprotective potential of X (17, 23, 38, 39). Neurons grown in microfluidic‐based culture devices were transduced with lentiviral vectors expressing X, X Δ2–4 , X A4 , or the nonmitochondrial X A6A7 as a control.…”

Image Informatics Strategies for Deciphering Neuronal Network Connectivity

“…Although there is a limited availability of tools that implement synapse detection, SynD was successfully used in knockout studies aimed at identifying proteins that are involved in synaptic transmission pathways, such as neurotransmitter vesicle fusion 75 and neurotransmitter receptor trafficking 76 . This tool was later used to evaluate the efficacy of synapto-protective drugs in a micro-fluidics screening platform 77 .…”