title: Mechanism of Oxidative Stress and Synapse Dysfunction in the Pathogenesis of Alzheimer's Disease: Understanding the Therapeutics Strategies.
abstract: Synapses are formed by interneuronal connections that permit a neuronal cell to pass an electrical or chemical signal to another cell. This passage usually gets damaged or lost in most of the neurodegenerative diseases. It is widely believed that the synaptic dysfunction and synapse loss contribute to the cognitive deficits in patients with Alzheimer's disease (AD). Although pathological hallmarks of AD are senile plaques, neurofibrillary tangles, and neuronal degeneration which are associated with increased oxidative stress, synaptic loss is an early event in the pathogenesis of AD. The involvement of major kinases such as mitogen-activated protein kinase (MAPK), extracellular receptor kinase (ERK), calmodulin-dependent protein kinase (CaMKII), glycogen synthase-3β (GSK-3β), cAMP response element-binding protein (CREB), and calcineurin is dynamically associated with oxidative stress-mediated abnormal hyperphosphorylation of tau and suggests that alteration of these kinases could exclusively be involved in the pathogenesis of AD. N-methyl-D-aspartate (NMDA) receptor (NMDAR) activation and beta amyloid (Aβ) toxicity alter the synapse function, which is also associated with protein phosphatase (PP) inhibition and tau hyperphosphorylation (two main events of AD). However, the involvement of oxidative stress in synapse dysfunction is poorly understood. Oxidative stress and free radical generation in the brain along with excitotoxicity leads to neuronal cell death. It is inferred from several studies that excitotoxicity, free radical generation, and altered synaptic function encouraged by oxidative stress are associated with AD pathology. NMDARs maintain neuronal excitability, Ca(2+) influx, and memory formation through mechanisms of synaptic plasticity. Recently, we have reported the mechanism of the synapse redox stress associated with NMDARs altered expression. We suggest that oxidative stress mediated through NMDAR and their interaction with other molecules might be a driving force for tau hyperphosphorylation and synapse dysfunction. Thus, understanding the oxidative stress mechanism and degenerating synapses is crucial for the development of therapeutic strategies designed to prevent AD pathogenesis.
authors.affiliation: Division of Physiology and Biophysics, School of Medicine, University of Louisville, Louisville, KY, 40202, USA. pkkama01@louisville.edu.
authors.forename: Pradip K
authors.initials: PK
authors.lastname: Kamat
authors.affiliation: Division of Physiology and Biophysics, School of Medicine, University of Louisville, Louisville, KY, 40202, USA.
authors.forename: Anuradha
authors.initials: A
authors.lastname: Kalani
authors.affiliation: Division of Pharmacology, Central Drug Research Institute (CDRI), P.O. Box 173, Lucknow, 226001, UP, India.
authors.forename: Shivika
authors.initials: S
authors.lastname: Rai
authors.affiliation: Scripp Institute, Jupiter, FL, 33458, USA.
authors.forename: Supriya
authors.initials: S
authors.lastname: Swarnkar
authors.affiliation: Division of Pharmacology, Central Drug Research Institute (CDRI), P.O. Box 173, Lucknow, 226001, UP, India.
authors.forename: Santoshkumar
authors.initials: S
authors.lastname: Tota
authors.affiliation: Division of Pharmacology, Central Drug Research Institute (CDRI), P.O. Box 173, Lucknow, 226001, UP, India.
authors.forename: Chandishwar
authors.initials: C
authors.lastname: Nath
authors.affiliation: Division of Physiology and Biophysics, School of Medicine, University of Louisville, Louisville, KY, 40202, USA.
authors.forename: Neetu
authors.initials: N
authors.lastname: Tyagi
mesh_terms: D000544:Alzheimer Disease / Q000188:drug therapy* / Q000378:metabolism* / Q000473:pathology; D000818:Animals; D001921:Brain / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D004791:Enzyme Inhibitors / Q000494:pharmacology / Q000627:therapeutic use; D006801:Humans; D018384:Oxidative Stress / Q000187:drug effects / Q000502:physiology*; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors / Q000378:metabolism; D013569:Synapses / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D016875:tau Proteins / Q000378:metabolism
chemical_list: D004791:Enzyme Inhibitors; D016194:Receptors, N-Methyl-D-Aspartate; D016875:tau Proteins
keywords: Alzheimer’s disease; Kinases; NMDA receptor; Oxidative stress; Synaptic function; Tau protein