P23 Acts as Functional RBP in the Macrophage Inflammation Response

Sebastian de Vries; Vladimir Benes; Isabel S Naarmann-de Vries; Cornelia Rücklé; Katharina Zarnack; Gernot Marx; Dirk H Ostareck; Antje Ostareck-Lederer

doi:10.3389/fmolb.2021.625608

P23 Acts as Functional RBP in the Macrophage Inflammation Response

Front Mol Biosci. 2021 Jun 11:8:625608. doi: 10.3389/fmolb.2021.625608. eCollection 2021.

Authors

Sebastian de Vries¹, Vladimir Benes², Isabel S Naarmann-de Vries¹, Cornelia Rücklé³, Katharina Zarnack³, Gernot Marx¹, Dirk H Ostareck¹, Antje Ostareck-Lederer¹

Affiliations

¹ Department of Intensive Care Medicine, University Hospital RWTH Aachen, Aachen, Germany.
² Genomics Core Facility, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany.
³ Buchmann Institute of Molecular Life Science, Goethe University Frankfurt, Frankfurt, Germany.

Abstract

Macrophages exert the primary cellular immune response. Pathogen components like bacterial lipopolysaccharides (LPS) stimulate macrophage migration, phagocytotic activity and cytokine expression. Previously, we identified the poly(A)⁺ RNA interactome of RAW 264.7 macrophages. Of the 402 RNA-binding proteins (RBPs), 32 were classified as unique in macrophages, including nineteen not reported to interact with nucleic acids before. Remarkably, P23 a HSP90 co-chaperone, also known as cytosolic prostaglandin E2 synthase (PTGES3), exhibited differential poly(A)⁺ RNA binding in untreated and LPS-induced macrophages. To identify mRNAs bound by P23 and to elucidate potential regulatory RBP functions in macrophages, we immunoprecipitated P23 from cytoplasmic extracts of cross-linked untreated and LPS-induced cells. RNAseq revealed that enrichment of 44 mRNAs was reduced in response to LPS. Kif15 mRNA, which encodes kinesin family member 15 (KIF15), a motor protein implicated in cytoskeletal reorganization and cell mobility was selected for further analysis. Noteworthy, phagocytic activity of LPS-induced macrophages was enhanced by P23 depletion. Specifically, in untreated RAW 264.7 macrophages, decreased P23 results in Kif15 mRNA destabilization, diminished KIF15 expression and accelerated macrophage migration. We show that the unexpected RBP function of P23 contributes to the regulation of macrophage phagocytotic activity and migration.

Keywords: Kif15 mRNA; P23/PTGES3; RNA-binding protein; macrophage inflammatory response; migration; phagocytosis; post-transcriptional control of gene expression.