title: Reciprocal Alterations in Regulator of G Protein Signaling 4 and microRNA16 in Schizophrenia.
abstract: N-methyl-d-aspartate receptor (NMDAR) hypofunction in the dorsolateral prefrontal cortex (DLPFC) has been implicated in the pathology of schizophrenia. NMDAR activity is negatively regulated by some G protein-coupled receptors (GPCRs). Signaling through these GPCRs is reduced by Regulator of G protein Signaling 4 (RGS4). Thus, lower levels of RGS4 would enhance GPCR-mediated reductions in NMDAR activity and could contribute to NMDAR hypofunction in schizophrenia. In this study, we quantified RGS4 mRNA and protein levels at several levels of resolution in the DLPFC from subjects with schizophrenia and matched healthy comparison subjects. To investigate molecular mechanisms that could contribute to altered RGS4 levels, we quantified levels of small noncoding RNAs, known as microRNAs (miRs), which regulate RGS4 mRNA integrity after transcription. RGS4 mRNA and protein levels were significantly lower in schizophrenia subjects and were positively correlated across all subjects. The RGS4 mRNA deficit was present in pyramidal neurons of DLPFC layers 3 and 5 of the schizophrenia subjects. In contrast, levels of miR16 were significantly higher in the DLPFC of schizophrenia subjects, and higher miR16 levels predicted lower RGS4 mRNA levels. These findings provide convergent evidence of lower RGS4 mRNA and protein levels in schizophrenia that may result from increased expression of miR16. Given the role of RGS4 in regulating GPCRs, and consequently the strength of NMDAR signaling, these findings could contribute to the molecular substrate for NMDAR hypofunction in DLPFC pyramidal cells in schizophrenia.
authors.affiliation: Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA; Department of Psychiatry, Nara Medical University, Nara, Japan;
authors.forename: Sohei
authors.initials: S
authors.lastname: Kimoto
authors.affiliation: Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA;
authors.forename: Jill R
authors.initials: JR
authors.lastname: Glausier
authors.affiliation: Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA;
authors.forename: Kenneth N
authors.initials: KN
authors.lastname: Fish
authors.affiliation: Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA;
authors.forename: David W
authors.initials: DW
authors.lastname: Volk
authors.affiliation: Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA;
authors.forename: H Holly
authors.initials: HH
authors.lastname: Bazmi
authors.affiliation: Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA;
authors.forename: Dominique
authors.initials: D
authors.lastname: Arion
authors.affiliation: Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA;
authors.forename: Dibyadeep
authors.initials: D
authors.lastname: Datta
authors.affiliation: Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA; Department of Neuroscience, University of Pittsburgh, Pittsburgh, PA lewisda@upmc.edu.
authors.forename: David A
authors.initials: DA
authors.lastname: Lewis
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D035683:MicroRNAs / Q000378:metabolism*; D008875:Middle Aged; D017397:Prefrontal Cortex / Q000378:metabolism*; D011618:Psychotic Disorders / Q000378:metabolism*; D020710:RGS Proteins / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D012559:Schizophrenia / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*
chemical_list: D035683:MicroRNAs; D020710:RGS Proteins; D012333:RNA, Messenger; C098799:RGS4 protein
keywords: GPCR; NMDA receptor; RGS4; miR16; microRNA; prefrontal cortex