Purine Signaling and Microglial Wrapping
Microglial cells are highly dynamic cells with processes continuously moving to survey the surrounding territory. Microglia possess a broad variety of surface receptors and subtle changes in their microenvironment cause microglial cell processes to extend
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Abstract Microglial cells are highly dynamic cells with processes continuously moving to survey the surrounding territory. Microglia possess a broad variety of surface receptors and subtle changes in their microenvironment cause microglial cell processes to extend, retract, and interact with neuronal synaptic contacts. When the nervous system is disturbed, microglia activate, proliferate, and migrate to sites of injury in response to alert signals. Released nucleotides like ATP and UTP are among the wide range of molecules promoting microglial activation and guiding their migration and phagocytic function. The increased concentration of nucleotides in the extracellular space could be involved in the microglial wrapping found around injured neurons in various pathological conditions, especially after peripheral axotomy. Microglial wrappings isolate injured neurons from synaptic inputs and facilitate the molecular dialog between endangered or injured neurons and activated microglia. Astrocytes may also participate in neuronal ensheathment. Degradation of ATP by microglial ecto-nucleotidases and the expression of various purine receptors might be decisive in regulating the function of enwrapping glial cells and in determining the fate of damaged neurons, which may die or may regenerate their axons and survive.
Keywords ATP Adenosine CD39 ‘Eat-me’ signals Neuronal degeneration Nerve injury Microglial migration Phagocytosis Purine receptors Axotomy
Abbreviations CNS PAMPs DAMPs TLRs
Central nervous system Pathogen associated molecular patterns Damage associated molecular patterns Toll-like receptors
B. Castellano (&) M. Bosch-Queralt B. Almolda N. Villacampa B. González Unit of Histology, Torre M5, Department of Cell Biology, Physiology and Immunology, Institute of Neurosciences, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain e-mail: [email protected] © Springer International Publishing Switzerland 2016 R. von Bernhardi (ed.), Glial Cells in Health and Disease of the CNS, Advances in Experimental Medicine and Biology 949, DOI 10.1007/978-3-319-40764-7_7
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SAMPs TREM2 PPT ECM
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