title: Expression pattern of the thrombopoietin receptor (Mpl) in the murine central nervous system.
abstract: BACKGROUND
  Thrombopoietin (Thpo) and its receptor (Mpl), which regulate megakaryopoiesis, are expressed in the central nervous system (CNS), where Thpo is thought to exert pro-apoptotic effects on newly generated neurons. Mpl expression has been analysed in brain tissue on transcript level and in cultured primary rat neurons and astrocytes on protein level. Herein, we analysed Mpl expression in the developing and adult murine CNS by immunohistochemistry and investigated the brain of mice with homozygous Mpl deficiency (Mpl-/-) by MRI.
  
  
  RESULTS
  Mpl was not detectable at developmental stages E12 to E15 in any resident cells of the CNS. From E18 onwards, robust Mpl expression was found in various brain areas, including cerebral cortex, olfactory bulb, thalamus, hypothalamus, medulla, pons, and the grey matter of spinal cord. However, major developmental changes became obvious: In the subventricular zone of the cerebral cortex Mpl expression occurred only during late gestation, while in the hippocampus Mpl expression was detectable for first time at stage P4. In the white matter of the cerebellum Mpl expression was restricted to the perinatal period. In the adult cerebellum, Mpl expression switched to Purkinje cell. The majority of other Mpl-positive cells were NeuN-positive neurons. None of the cells could be double-labelled with astrocyte marker GFAP. Mpl-/- mice showed no gross abnormalities of the brain.
  
  
  CONCLUSIONS
  Our data locate Mpl expression to neurons at different subdivisions of the spinal cord, rhombencephalon, midbrain and prosencephalon. Besides neuronal cells Mpl protein is also expressed in Purkinje cells of the adult cerebellum.
authors.affiliation: Department of Neonatology, Charité - Universitätsmedizin, Germany.
authors.forename: Anna
authors.initials: A
authors.lastname: Ivanova
authors.forename: Jens
authors.initials: J
authors.lastname: Wuerfel
authors.forename: Juan
authors.initials: J
authors.lastname: Zhang
authors.forename: Olaf
authors.initials: O
authors.lastname: Hoffmann
authors.forename: Matthias
authors.initials: M
authors.lastname: Ballmaier
authors.forename: Christof
authors.initials: C
authors.lastname: Dame
mesh_terms: D000818:Animals; D001921:Brain / Q000166:cytology / Q000196:embryology* / Q000378:metabolism*; D002478:Cells, Cultured; D015870:Gene Expression; D051379:Mice; D051381:Rats; D053628:Receptors, Thrombopoietin / Q000235:genetics*; D013926:Thrombopoietin / Q000378:metabolism
chemical_list: C481270:Mpl protein, mouse; D053628:Receptors, Thrombopoietin; D013926:Thrombopoietin