title: The adenosine generating enzymes CD39/CD73 control microglial processes ramification in the mouse brain.
abstract: Microglial cells invade the brain as amoeboid precursors and acquire a highly ramified morphology in the postnatal brain. Microglia express all essential purinergic elements such as receptors, nucleoside transporters and ecto-enzymes, including CD39 (NTPDase1) and CD73 (5'-nucleotidase), which sequentially degrade extracellular ATP to adenosine. Here, we show that constitutive deletion of CD39 and CD73 or both caused an inhibition of the microglia ramified phenotype in the brain with a reduction in the length of processes, branching frequency and number of intersections with Sholl spheres. In vitro, unlike wild-type microglia, cd39-/- and cd73-/- microglial cells were less complex and did not respond to ATP with the transformation into a more ramified phenotype. In acute brain slices, wild-type microglia retracted approximately 50% of their processes within 15 min after slicing of the brain, and this phenomenon was augmented in cd39-/- mice; moreover, the elongation of microglial processes towards the source of ATP or towards a laser lesion was observed only in wild-type but not in cd39-/- microglia. An elevation of extracellular adenosine 1) by the inhibition of adenosine transport with dipyridamole, 2) by application of exogenous adenosine or 3) by degradation of endogenous ATP/ADP with apyrase enhanced spontaneous and ATP-induced ramification of cd39-/- microglia in acute brain slices and facilitated the transformation of cd39-/- and cd73-/- microglia into a ramified process-bearing phenotype in vitro. These data indicate that under normal physiological conditions, CD39 and CD73 nucleotidases together with equilibrative nucleoside transporter 1 (ENT1) control the fate of extracellular adenosine and thereby the ramification of microglial processes.
authors.affiliation: Cellular Neurosciences, Max-Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany.
authors.forename: Marina
authors.initials: M
authors.lastname: Matyash
authors.affiliation: Cellular Neurosciences, Max-Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany.
authors.forename: Oleksandr
authors.initials: O
authors.lastname: Zabiegalov
authors.affiliation: Cellular Neurosciences, Max-Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Wendt
authors.affiliation: Cellular Neurosciences, Max-Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany.|Department of Neuropathology, Charité-Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: Vitali
authors.initials: V
authors.lastname: Matyash
authors.affiliation: Cellular Neurosciences, Max-Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany.
authors.forename: Helmut
authors.identifier: http://orcid.org/0000-0001-8208-0291
authors.initials: H
authors.lastname: Kettenmann
mesh_terms: D015720:5'-Nucleotidase / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D000241:Adenosine / Q000378:metabolism* / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D000831:Animals, Newborn; D015703:Antigens, CD / Q000235:genetics / Q000378:metabolism*; D001081:Apyrase / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D001921:Brain / Q000166:cytology* / Q000254:growth & development / Q000378:metabolism*; D001930:Brain Injuries / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D002452:Cell Count; D002478:Cells, Cultured; D002633:Chemotaxis; D004176:Dipyridamole / Q000494:pharmacology; D004195:Disease Models, Animal; D033721:Equilibrative Nucleoside Transporter 1 / Q000378:metabolism; D053858:Metabolic Networks and Pathways; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic; D017628:Microglia / Q000166:cytology* / Q000378:metabolism*; D010641:Phenotype; D058925:Receptors, Purinergic P2Y12 / Q000378:metabolism
chemical_list: D015703:Antigens, CD; D033721:Equilibrative Nucleoside Transporter 1; C548577:P2ry12 protein, mouse; D058925:Receptors, Purinergic P2Y12; C498476:SLC29A1 protein, mouse; D004176:Dipyridamole; D000255:Adenosine Triphosphate; D015720:5'-Nucleotidase; D001081:Apyrase; C067869:CD39 antigen; D000241:Adenosine