title: Spinal cord injury induces expression of RGS7 in microglia/macrophages in rats.
abstract: RGS proteins regulate G protein-mediated signalling pathways through direct interaction with the Galpha subunits and facilitation of GTP hydrolysis. An RGS subfamily consisting of RGS 6, 7, 9, and 11 also interacts with the G protein beta subunit Gbeta5 via a characteristic Ggamma-like domain. Thus far, these complexes were found only in neurons, with RGS7 being the most widely distributed in the brain. Here we confirm the expression of RGS7 in spinal neurons and show as a novel finding that following an experimental spinal cord injury in rats, expression of RGS7 is induced in a subpopulation of other cells. Immunofluorescent confocal microscopy using a series of cell specific antibodies identified these RGS7 positive cells as activated microglia and/or invading peripheral macrophages. To rule out interference from the adjacent neurons and confirm the presence of RGS7-Gbeta5 complex in inflammatory cells, we performed immunocytochemistry, RT-PCR, Western blot, and immunoprecipitation using microglial (BV2) and peripheral macrophage (RAW) cell lines. Expression of RGS7 mRNA and protein are nearly undetectable in non-stimulated BV2 and RAW cells, but remarkably increased after stimulation with LPS or TNF-alpha In addition, RGS7-positive cells were also found in the perinodular rim in the rat spleen. Our findings show that RGS7-Gbeta5 complex is expressed in immunocompetent cells such as resident microglia and peripheral macrophages following spinal cord injury. This expression might contribute to the post-traumatic inflammatory responses in the central nervous system.
authors.affiliation: The Miami Project to Cure Paralysis, Miami, Florida, USA.
authors.forename: Oliver N
authors.initials: ON
authors.lastname: Hausmann
authors.forename: Wen-Hui
authors.initials: WH
authors.lastname: Hu
authors.forename: Tal
authors.initials: T
authors.lastname: Keren-Raifman
authors.forename: D Scott
authors.initials: DS
authors.lastname: Witherow
authors.forename: Qiang
authors.initials: Q
authors.lastname: Wang
authors.forename: Konstantin
authors.initials: K
authors.lastname: Levay
authors.forename: Beata
authors.initials: B
authors.lastname: Frydel
authors.forename: Vladlen
authors.initials: V
authors.lastname: Z  Slepak
authors.forename: John
authors.initials: J
authors.lastname: R  Bethea
mesh_terms: D000818:Animals; D001253:Astrocytes / Q000166:cytology / Q000378:metabolism; D002478:Cells, Cultured; D005260:Female; D044387:GTP-Binding Protein beta Subunits; D019204:GTP-Binding Proteins; D020962:Heterotrimeric GTP-Binding Proteins / Q000378:metabolism*; D007150:Immunohistochemistry; D008070:Lipopolysaccharides / Q000494:pharmacology; D008264:Macrophages / Q000166:cytology / Q000378:metabolism*; D017628:Microglia / Q000166:cytology / Q000378:metabolism*; D009187:Myelitis / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D009474:Neurons / Q000166:cytology / Q000378:metabolism; D009836:Oligodendroglia / Q000166:cytology / Q000378:metabolism; D020710:RGS Proteins / Q000378:metabolism*; D051381:Rats; D011916:Rats, Inbred F344; D013116:Spinal Cord / Q000187:drug effects* / Q000378:metabolism / Q000503:physiopathology; D013119:Spinal Cord Injuries / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D015854:Up-Regulation / Q000502:physiology*
chemical_list: D044387:GTP-Binding Protein beta Subunits; C490610:Gnb5 protein, rat; D008070:Lipopolysaccharides; D020710:RGS Proteins; C492038:Rgs7 protein, mouse; C115771:Rgs7 protein, rat; D014409:Tumor Necrosis Factor-alpha; D019204:GTP-Binding Proteins; D020962:Heterotrimeric GTP-Binding Proteins