Quantitative Proteomics Reveal an Altered Pattern of Protein Expression in Brain Tissue from Mice Lacking GPR37 and GPR37L1

• Type of Material: Article
• Authors: TrangKimberly Thu Nguyen, Emory University; Eric Dammer, Emory University; Sharon A. Owino, Emory University; Michelle M. Giddens, Emory University; Nora S. Madaras, Emory University; Duc M. Duong, Emory University; Nicholas Seyfried, Emory University; Randy Hall, Emory University
• Language: English
• Date: 2020-02-01
• Publisher: ACS Publications
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2020 American Chemical Society
• Final Published Version (URL): http://dx.doi.org/10.1021/acs.jproteome.9b00622
• Title of Journal or Parent Work: Journal of Proteome Research
• Volume: 19
• Issue: 2
• Start Page: 744
• End Page: 755
• Grant/Funding Information: This work was funded by NIH grants R21-NS91986, R21-NS106323, and R01-NS088413, and T.T.N. was supported by NIH training grant T32-GM008602.
• Keywords: calcium; Binding protein; Parkinsons-disease; secretion; Differential expression; Synaptosomal particulate fractions; Life Sciences & Biomedicine; Mouse; astrocyte; Calcium; Astrocytes; S100A5; oligodendrocyte; S100B; calcium-binding protein; Biochemical Research Methods; S-100 Protein; Coupled peptide receptor; glia; Science & Technology; Biochemistry & Molecular Biology
• Research Categories: Chemistry, Biochemistry; Biology, Molecular; Biology, Neuroscience

Abstract

GPR37 and GPR37L1 are glia-enriched G protein-coupled receptors that have been implicated in several neurological and neurodegenerative diseases. To gain insight into the potential molecular mechanisms by which GPR37 and GPR37L1 regulate cellular physiology, proteomic analyses of whole mouse brain tissue from wild-type (WT) versus GPR37/GPR37L1 double knockout (DKO) mice were performed in order to identify proteins regulated by the absence versus presence of these receptors (data are available via ProteomeXchange with identifier PXD015202). These analyses revealed a number of proteins that were significantly increased or decreased by the absence of GPR37 and GPR37L1. One of the most decreased proteins in the DKO versus WT brain tissue was S100A5, a calcium-binding protein, and the reduction of S100A5 expression in KO brain tissue was validated via Western blot. Coexpression of S100A5 with either GPR37 or GPR37L1 in HEK293T cells did not result in any change in S100A5 expression but did robustly increase secretion of S100A5. To dissect the mechanism by which S100A5 secretion was enhanced, cells coexpressing S100A5 with the receptors were treated with different pharmacological reagents. These studies revealed that calcium is essential for the secretion of S100A5 downstream of GPR37 and GPR37L1 signaling, as treatment with BAPTA-AM, an intracellular Ca2+ chelator, reduced S100A5 secretion from transfected HEK293T cells. Collectively, these findings provide a panoramic view of proteomic changes resulting from loss of GPR37 and GPR37L1 and also impart mechanistic insight into the regulation of S100A5 by these receptors, thereby shedding light on the functions of GPR37 and GPR37L1 in brain tissue.