Reconstructive Neuroscience

The role of perineural networks in-memory storage

Perineuronal networks (PNNs) play a key role in the maturation and plasticity of neurons and synapses. PNNs affect the formation, retention, and extinction of memory in various animal models. According to a recently published study, the eyes and cavities in the PNN contain synapses and can therefore function as a memory repository that is even stable in conditions during which synapse retraction occurs, such as anoxia or hibernation. We studied this theory in mice put into a state resembling hibernation, in which there is a retraction of synapses and, at the same time, we monitored the spatial memory of these animals before and after hibernation. We used normal animals and animals that had an absence of nets in the hippocampus area; either due to cleavage by the enzyme chondroitinase ABC or genetically removed aggrecan, which is an important part of PNN. In our model, synapse retraction during hibernation caused memory deficits, but not to the level of naive animals. Both groups with enzymatically cleaved networks (hibernating and non-hibernating) had changes in the level of synaptic proteins located on parvalbumin neurons in the hippocampus during and after hibernation, which resulted in faster re-learning in the Morris water maze compared to mice in hibernation and the retraction of synapses preserved by PNN. Chondroitinase did not alter the memory deficit, while the long-term absence of PNN in the aggrecan knockout group led to partial memory retention, but there was no improvement in re-learning the task in the water maze.

The reduction of perineural networks by a hyaluronan synthase inhibitor improves the cognitive memory in mice

Hyaluronan (HA) is the basic molecule of the extracellular matrix in the central nervous system that forms the perineuronal networks (PNNs) that surround the subpopulations of neurons. PNNs control synaptic stabilization both during development and in the adult brain, and PNN disruption has shown the reactivation of nerve plasticity. We investigated the possibility of memory prolongation by reducing PNN production by an inhibitor of HA synthesis. Adult mice were fed a diet containing a 5% HA synthesis inhibitor for 6 months. This application reduced the level of glycosaminoglycans in the brain to 72% compared to the controls. The memory was tested using the New-Object Recognition Test (NOR) and the Spontaneous Alternation Test (SA). NOR tests were performed at 2, 3, 6 and 7 months with a delay of 3 h and 24 h after exposure to the subjects. A significant improvement in the NOR score was found in the animals treated with 4-MU at 3 and 6 months after a 24-hour delay, compared to the control group. However, 1 month after the end of treatment, the effect of the HA synthesis inhibitor on memory increase did not persist. Immunohistochemistry confirmed a decrease in PNN by lower intensity staining of Wisteria floribunda around neurons. In addition, a shorter and less arborization of aggrecan networks was observed around dendrites in the hippocampus after 6 months of HA synthesis inhibitor treatment.

2023

• The cooperation with Prof. Britta Eickholt from Charite University (Berlin) resulted in a joint Mobility Grant awarded by the CAS and DAAD, within the frame of which students from both departments are exchanged.
• Collaboration with Joost Verhaagen from Amsterdam has enabled additional preparation of viral vectors in his laboratory also in 2023 (Dr. Kristýna Kárová and Lydia Knight).
• In March 2023, B. Niuvenhuis, R. Eva and E. Bradbury visited the Centre and discussed the results of the joint projects and further collaborations planned for the sustainability period.

2022

• A new grant “Hyperactive PI3 kinase and activated integrin for corticospinal regeneration” started (supported by the Swiss International Foundation for Research in Paraplegia)
• Several foreign internships took place – Institute of Biochemistry, Charité-Universitätsmedizin Berlin, University King’s College London
• Presentation of project results at the FENS 2022 congress in Paris, the Miami axon repair workshop, the 7th Neurological Disorders Summit in San Francisco, the AMBRA conference in Wrocław, the TERMIS EU European Congress in Krakow, the conference of the American Neuroscience Society
• “Regeneration meeting” was organized in May 2022 with the participation of members of the laboratory of prof. Elizabeth Bradbury (King’s College London)
• Minisymposium “Regeneration and plasticity of the central nervous system” took place with the participation of several foreign speakers
• Dr Kwok gave a plenary lecture “The Role of Extracellular Matrix in Nervous System Regeneration” at the Biocev Days conference
• Team members participated in popularization events Brain Awareness Week, The Week of the Czech Academy of Sciences, Researchers’ Night.

2021

• conference Regeneration I with the participation of partner organizations from Poland, Slovakia and Hungary (Massakowski Medical Research Centre Polish Academy of Sciences, Neuroimunologický ústav SAK, BioTalentum Ltd.), BIOCEV, Vestec
• presentation of project results – The 13th Conference of the Czech Neuroscience Society, Prague
• presentation of project results – The 19th Congress of the Czech and Slovak Spine Society, Špindlerův Mlýn

2020

• lecture prof. Dr. Andreas Faissner (Department of Cell Morphology & Molecular Neurobiology , Ruhr-University, Bochum, Německo) – Structural and functional characterization of the CNS matrisome
• new grants: Visegrad fund „V4RM – Bridging the gap between science, education and enterprise in regenerative medicine“ and EMBO short-term fellowship
• presentation of results at the VIBes in Biosciences 2020 conference, Belgium

2019

• lecture by prof. Mark H. Tuszynski, M.D., Ph.D. (Director, Center for Neural Repair, Department of Neurosciences, University of California – San Diego) – Neural Stem Cells for Spinal Cord Injury
• lecture by prof. Martin E. Schwab (Institute for Regenerative Medicine, University of Zurich and Dept. of Health Sciences and Technology, ETH Zurich) – Neurobiological mechanisms of functional recovery after spinal cord injury or stroke; from the lab bench to the clinic with a neurite growth-enhancing therapy
• presentation of project results at the TERMIS European Chapter Meeting 2019, Greece
• presentation of results at conference XIV. European Meeting on Glial Cells in Health and Diseases, Portugal
• study stay of a member of the implementation team at the University of Leeds, Great Britain – the study of the effect of ECM disruption in the spinal cord lesion on the regeneration of spinal cord tissue
• lecture by prof. Catherina G. Becker, FRSB (Center for Discovery Brain Sciences, The University of Edinburgh) – The immune systems controls successful spinal cord repair in zebrafish
• presentation of results at the SFN Neuroscience 2019 conference

2018

• lecture by Dr. Elisabeth Bradbury (King’s College London) – Restoring function after spinal cord injury: targeting glial scar matrix and endogenous repair processes
• lecture by Dr. Kristiana Franzeho (Department of Physiology, Development and Neuroscience University of Cambridge) – The mechanical regulation of neuronal development and regeneration
• lecture by prof. Joosta Verhaagena (Netherlands Institute for Neuroscience) – Neuronal regeneration: from gene networks to gene therapy
• lecture by prof. Britty Eickholt (Charité – Universitätsmedizin Berlin) – Injury induced drebrin controls astrogliosis and scar formation by regulating tubular endosomes and adhesion responses
• Mgr. Neumann participated in a 3-day workshop on the application of viral vectors to spinal ganglia at the Netherlands Institute for Neuroscience, Amsterdam
• three-month internship with Mgr. Hahn in the laboratory of Joao Relvas, Institute for Molecular and Cell Biology, University of Porto
• Conference – Controlling neuronal plasticity – developmental disorders and repair in Villa Lanna, Prague

2017

• conference – Regeneration, Plasticity, Protection (Prof. James Fawcett)
• a two-day workshop of experts from the JOHN VAN GEEST CENTER FOR BRAIN REPAIR, which falls under the Department of Clinical Neuroscience at the University of Cambridge
• DRG INJECTION WORKSHOP (Dr. Menghon Cheah)
• Perineuronal net treatments for memory loss (Dr. Sujeong Yang)
• training workshop on the topic of in situ isolation of DRG in the cervical and lumbar spine, accompanied by practical examples of how to open the correct vertebrae and identify the appropriate dorsal ganglia
• established cooperation with Dr. Vincenzo de Paola of Imperial College London (in vivo imaging of organotypic sections) and Dr. Diego Peretti of the University of Cambridge (hibernation model)
• three-month internship with Dr. Růžičky at the workplace of Dr. Vincenza di Paola
• lecture by prof. Toshitaka Oohashi – The Hyaluronan and Proteoglycan Link Proteins: Organizers of the Brain ECM and Key Molecules for Neuronal Function and Plasticity
• internship Mgr. Dubišová at the University of Cambridge
• participation of project members at the TERMIS EU 2017 Congress of Tissue Engineering and Regenerative Medicine, organization of the symposium “New trends in CNS repair” within the congress, three lectures and two poster presentations
• established cooperation with the group of Dr. Andras Lakatos from Cambridge, lecture on the topic: Regulatory networks controlling protective and detrimental astrocyte phenotypes in injury and ALS.
• During the year, the Center’s workplace was gradually built and investment equipment, including a Lightsheet microscope, was purchased