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    Dr Ragnhildur Thora Karadottir

    University Position
    Research Fellow


    My lab's interests are neurotransmitter signalling to oligodendrocytes and their progenitor cells, in both health and disease. Oligodendrocytes produce myelin (in the CNS), which speeds the propagation of the action potential. When the myelin sheath is lost or not formed, in diseases like cerebral palsy, spinal cord injury and multiple sclerosis, it causes mental and physical disability. We study how oligodendrocytes respond to neurotransmitters released from axons, both in the normal brain and in pathological conditions. Oligodendrocyte precursor cells (OPCs) comprise 5% of the cells in the adult brain, where they are the main proliferative cells present. They can generate both neurons and glial cells, making them an important stem cell population in the adult brain. We study how neuronal activity can regulate OPC differentiation, in both the normal brain and pathological conditions.

    Key Publications

    Signal requirement for cortical potential of transplantable human neuroepithelial stem cells.

    Journal: Nat Commun
    E-pub date: 23 May 2022
    Authors: BV Varga, M Faiz, H Pivonkova, G Khelifi, H Yang, S Gao, E Linderoth, M Zhen, RT Karadottir, SM Hussein, A Nagy

    Subependymal Zone-Derived Oligodendroblasts Respond to Focal Demyelination but Fail to Generate Myelin in Young and Aged Mice.

    Journal: Stem Cell Reports
    E-pub date: 14 Mar 2017
    Authors: I Kazanis, KA Evans, E Andreopoulou, C Dimitriou, C Koutsakis, RT Karadottir, RJM Franklin

    Astrocyte response to motor neuron injury promotes structural synaptic plasticity via STAT3-regulated TSP-1 expression.

    Journal: Nat Commun
    E-pub date: 11 Jul 2014
    Authors: GE Tyzack, S Sitnikov, D Barson, KL Adams-Carr, NK Lau, JC Kwok, C Zhao, RJM Franklin, RT Karadottir, JW Fawcett, A Lakatos


    iPS-cell-derived microglia promote brain organoid maturation via cholesterol transfer.

    Journal: Nature
    E-pub date: 1 Nov 2023
    Authors: DS Park, T Kozaki, SK Tiwari, M Moreira, A Khalilnezhad, F Torta, N Olivié, CH Thiam, O Liani, A Silvin, WW Phoo, L Gao, A Triebl, WK Tham, L Gonçalves, WT Kong, S Raman, XM Zhang, G Dunsmore, CA Dutertre, S Lee, JM Ong, A Balachander, S Khalilnezhad, J Lum, K Duan, ZM Lim, L Tan, I Low, KH Utami, XY Yeo, S Di Tommaso, J-W Dupuy, B Varga, RT Karadottir, MC Madathummal, I Bonne, B Malleret, ZY Binte, N Wei Da, Y Tan, WJ Wong, J Zhang, J Chen, RM Sobota, SW Howland, LG Ng, F Saltel, D Castel, J Grill, V Minard, S Albani, JKY Chan, MS Thion, SY Jung, MR Wenk, MA Pouladi, C Pasqualini, V Angeli, ONF Cexus, F Ginhoux

    Human astrocytes and microglia show augmented ingestion of synapses in Alzheimer’s disease via MFG-E8.

    Journal: Cell Rep Med
    E-pub date: 19 Sep 2023
    Authors: M Tzioras, MJD Daniels, C Davies, P Baxter, D King, S McKay, B Varga, K Popovic, M Hernandez, AJ Stevenson, J Barrington, E Drinkwater, J Borella, RK Holloway, J Tulloch, J Moss, C Latta, J Kandasamy, D Sokol, C Smith, VE Miron, RT Káradóttir, GE Hardingham, CM Henstridge, PM Brennan, BW McColl, TL Spires-Jones

    Electrochemically induced in vitro focal hypoxia in human neurons.

    Journal: Front Cell Dev Biol
    E-pub date: 1 Aug 2022
    Authors: JJY Wong, BV Varga, RT Káradóttir, EAH Hall

    Periods of synchronized myelin changes shape brain function and plasticity.

    Journal: Nat Neurosci
    E-pub date: 1 Nov 2021
    Authors: O de Faria, H Pivonkova, B Varga, S Timmler, KA Evans, RT Káradóttir

    Nutritional regulation of oligodendrocyte differentiation regulates perineuronal net remodeling in the median eminence.

    Journal: Cell Rep
    E-pub date: 13 Jul 2021
    Authors: S Kohnke, S Buller, D Nuzzaci, K Ridley, B Lam, H Pivonkova, MA Bentsen, KM Alonge, C Zhao, J Tadross, S Holmqvist, T Shimizu, H Hathaway, H Li, W Macklin, MW Schwartz, WD Richardson, GSH Yeo, RJM Franklin, RT Karadottir, DH Rowitch, C Blouet

    Niche derived oligodendrocyte progenitors: a source of rejuvenation or complementation for local oligodendrogenesis?

    Journal: Front Cell Neurosci
    E-pub date: 1 Aug 2013
    Authors: S Agathou, RT Káradóttir, I Kazanis