Adenosine kinase is a target for the prediction and prevention of epileptogenesis in mice.

Astrogliosis is a pathological hallmark of the epileptic brain. The identification of mechanisms that link astrogliosis to neuronal dysfunction in epilepsy may provide new avenues for therapeutic intervention. Here we show that astrocyte-expressed adenosine kinase (ADK), a key negative regulator of the brain inhibitory molecule adenosine, is a potential predictor and modulator of epileptogenesis. In a mouse model of focal epileptogenesis, in which astrogliosis is restricted to the CA3 region of the hippocampus, we demonstrate that upregulation of ADK and spontaneous focal electroencephalographic seizures were both restricted to the affected CA3. Furthermore, spontaneous seizures in CA3 were mimicked in transgenic mice by overexpression of ADK in this brain region, implying that overexpression of ADK without astrogliosis is sufficient to cause seizures. Conversely, after pharmacological induction of an otherwise epileptogenesis-precipitating acute brain injury, transgenic mice with reduced forebrain ADK were resistant to subsequent epileptogenesis. Likewise, ADK-deficient ES cell-derived brain implants suppressed astrogliosis, upregulation of ADK, and spontaneous seizures in WT mice when implanted after the epileptogenesis-precipitating brain injury. Our findings suggest that astrocyte-based ADK provides a critical link between astrogliosis and neuronal dysfunction in epilepsy.

[1]  M. During,et al.  Adenosine: A potential mediator of seizure arrest and postictal refractoriness , 1992, Annals of neurology.

[2]  Peter Schubert,et al.  The anticonvulsive action of adenosine: a postsynaptic, dendritic action by a possible endogenous anticonvulsant , 1984, Brain Research.

[3]  D. Boison Adenosine-Based Cell Therapy Approaches for Pharmacoresistant Epilepsies , 2007, Neurodegenerative Diseases.

[4]  N. Déglon,et al.  Grafts of adenosine-releasing cells suppress seizures in kindling epilepsy , 2001, Proceedings of the National Academy of Sciences of the United States of America.

[5]  R. Simon,et al.  Characterization of neuronal death induced by focally evoked limbic seizures in the C57BL/6 mouse , 2002, Journal of neuroscience research.

[6]  R. Simon,et al.  Transgenic Overexpression of Adenosine Kinase Aggravates Cell Death in Ischemia , 2007, Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism.

[7]  R. Cunha,et al.  Decrease of adenosine A1 receptor density and of adenosine neuromodulation in the hippocampus of kindled rats , 2003, The European journal of neuroscience.

[8]  T. Takano,et al.  An astrocytic basis of epilepsy , 2005, Nature Medicine.

[9]  A. Depaulis,et al.  Evolution of hippocampal epileptic activity during the development of hippocampal sclerosis in a mouse model of temporal lobe epilepsy , 2002, Neuroscience.

[10]  Thomas Rülicke,et al.  Astrogliosis in epilepsy leads to overexpression of adenosine kinase, resulting in seizure aggravation. , 2005, Brain : a journal of neurology.

[11]  Asla Pitkänen,et al.  Is epilepsy a progressive disorder? Prospects for new therapeutic approaches in temporal-lobe epilepsy , 2002, The Lancet Neurology.

[12]  E A Kowaluk,et al.  Therapeutic potential of adenosine kinase inhibitors , 2000, Expert opinion on investigational drugs.

[13]  S. Itohara,et al.  Dorsal telencephalon‐specific expression of Cre recombinase in PAC transgenic mice , 2004, Genesis.

[14]  B. Fredholm,et al.  Hyperalgesia, anxiety, and decreased hypoxic neuroprotection in mice lacking the adenosine A1 receptor , 2001, Proceedings of the National Academy of Sciences of the United States of America.

[15]  M. Segal,et al.  Development of neuronal precursor cells and functional postmitotic neurons from embryonic stem cells in vitro , 1996, Mechanisms of Development.

[16]  D. Boison Adenosine kinase, epilepsy and stroke: mechanisms and therapies. , 2006, Trends in pharmacological sciences.

[17]  A. Marowsky,et al.  Shift of adenosine kinase expression from neurons to astrocytes during postnatal development suggests dual functionality of the enzyme , 2006, Neuroscience.

[18]  P. Kochanek,et al.  Adenosine A1 Receptor Knockout Mice Develop Lethal Status Epilepticus after Experimental Traumatic Brain Injury , 2006, Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism.

[19]  Jiang Lan,et al.  Lentiviral RNAi-induced downregulation of adenosine kinase in human mesenchymal stem cell grafts: A novel perspective for seizure control , 2007, Experimental Neurology.

[20]  R. Simon,et al.  Bim regulation may determine hippocampal vulnerability after injurious seizures and in temporal lobe epilepsy. , 2004, The Journal of clinical investigation.

[21]  M. Jarvis,et al.  Anticonvulsant and antinociceptive actions of novel adenosine kinase inhibitors. , 2005, Current topics in medicinal chemistry.

[22]  R. Simon,et al.  Suppression of kindling epileptogenesis by adenosine releasing stem cell-derived brain implants. , 2007, Brain : a journal of neurology.

[23]  J. Geiger,et al.  Brain regional levels of adenosine and adenosine nucleotides in rats killed by high-energy focused microwave irradiation , 1996, Journal of Neuroscience Methods.

[24]  G. V. Goddard,et al.  Is Adenosine an Endogenous Anticonvulsant? , 1985, Epilepsia.

[25]  E. Newsholme,et al.  Activities and some properties of 5'-nucleotidase, adenosine kinase and adenosine deaminase in tissues from vertebrates and invertebrates in relation to the control of the concentration and the physiological role of adenosine. , 1978, The Biochemical journal.

[26]  T. Dunwiddie Endogenously Released Adenosine Regulates Excitability in the In Vitro Hippocampus , 1980, Epilepsia.

[27]  J. Feldon,et al.  Transgenic overexpression of adenosine kinase in brain leads to multiple learning impairments and altered sensitivity to psychomimetic drugs , 2007, The European journal of neuroscience.

[28]  S. Masino,et al.  Adenosine and ATP Link PCO2 to Cortical Excitability via pH , 2005, Neuron.

[29]  A. Shetty,et al.  Repair of the Injured Adult Hippocampus through Graft-Mediated Modulation of the Plasticity of the Dentate Gyrus in a Rat Model of Temporal Lobe Epilepsy , 2005, The Journal of Neuroscience.

[30]  G. Carmignoto,et al.  Astrocyte control of synaptic transmission and neurovascular coupling. , 2006, Physiological reviews.

[31]  B. Frenguelli,et al.  Endogenous adenosine modulates epileptiform activity in rat hippocampus in a receptor subtype‐dependent manner , 2004, The European journal of neuroscience.

[32]  R. Faull,et al.  Loss of A1 adenosine receptors in human temporal lobe epilepsy , 1996, Brain Research.

[33]  R. Cunha,et al.  Long‐term Effect of Convulsive Behavior on the Density of Adenosine A1 and A2A Receptors in the Rat Cerebral Cortex , 2005 .

[34]  B. Fowler,et al.  Neonatal hepatic steatosis by disruption of the adenosine kinase gene , 2002, Proceedings of the National Academy of Sciences of the United States of America.

[35]  Z. Emri,et al.  Epileptogenesis and chronic seizures in a mouse model of temporal lobe epilepsy are associated with distinct EEG patterns and selective neurochemical alterations in the contralateral hippocampus , 2005, Experimental Neurology.

[36]  E. Simpson,et al.  Engineering embryonic stem cell derived glia for adenosine delivery , 2004, Neuroscience Letters.

[37]  Rafael Yuste,et al.  Calcium oscillations in neocortical astrocytes under epileptiform conditions. , 2002, Journal of neurobiology.

[38]  M. Jarvis,et al.  Purinergic control of neuropathic pain , 2006 .

[39]  B. MacVicar,et al.  Modulation of neuronal excitability by astrocytes. , 1999, Advances in neurology.

[40]  J. Fritschy,et al.  Overexpression of Adenosine Kinase in Epileptic Hippocampus Contributes to Epileptogenesis , 2022 .

[41]  P. Svenningsson,et al.  Adenosine and brain function. , 2005, International review of neurobiology.

[42]  B. Fredholm,et al.  Adenosine A1 receptors are crucial in keeping an epileptic focus localized , 2006, Experimental Neurology.

[43]  F. Bontemps,et al.  Mechanisms of elevation of adenosine levels in anoxic hepatocytes. , 1993, The Biochemical journal.

[44]  H G Hers,et al.  Evidence for a substrate cycle between AMP and adenosine in isolated hepatocytes. , 1983, Proceedings of the National Academy of Sciences of the United States of America.

[45]  T. Dunwiddie,et al.  Adenosine and suppression of seizures. , 1999, Advances in neurology.

[46]  D. Boison Adenosine and Epilepsy: From Therapeutic Rationale to New Therapeutic Strategies , 2005, The Neuroscientist : a review journal bringing neurobiology, neurology and psychiatry.