AUTHOR=Phelan David E. , Shigemura Masahiko , Aldhafiri Sarah , Mota Catarina , Hall Thomas J. , Sznajder Jacob I. , Murphy Evelyn P. , Crean Daniel , Cummins Eoin P. 

TITLE=Transcriptional Profiling of Monocytes Deficient in Nuclear Orphan Receptors NR4A2 and NR4A3 Reveals Distinct Signalling Roles Related to Antigen Presentation and Viral Response

JOURNAL=Frontiers in Immunology

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2021.676644

DOI=10.3389/fimmu.2021.676644

ISSN=1664-3224

ABSTRACT=<p>The nuclear receptor sub-family 4 group A (NR4A) family are early response genes that encode proteins that are activated in several tissues/cells in response to a variety of stressors. The NR4A family comprises <italic>NR4A1</italic>, <italic>NR4A2</italic> and <italic>NR4A3</italic> of which <italic>NR4A2</italic> and <italic>NR4A3</italic> are under researched and less understood, particularly in the context of immune cells. NR4A expression is associated with multiple diseases e.g. arthritis and atherosclerosis and the development of NR4A-targetting molecules as therapeutics is a current focus in this research field. Here, we use a combination of RNA-sequencing coupled with strategic bioinformatic analysis to investigate the down-stream effects of <italic>NR4A2</italic> and <italic>NR4A3</italic> in monocytes and dissect their common and distinct signalling roles. Our data reveals that <italic>NR4A2</italic> and <italic>NR4A3</italic> depletion has a robust and broad-reaching effect on transcription in both the unstimulated state and in the presence of LPS. Interestingly, many of the genes affected were present in both the unstimulated and stimulated states revealing a previously unappreciated role for the NR4As in unstimulated cells. Strategic clustering and bioinformatic analysis identified both distinct and common transcriptional roles for <italic>NR4A2</italic> and <italic>NR4A3</italic> in monocytes. <italic>NR4A2</italic> notably was linked by both bioinformatic clustering analysis and transcription factor interactome analysis to pathways associated with antigen presentation and regulation of MHC genes. <italic>NR4A3</italic> in contrast was more closely linked to pathways associated with viral response. Functional studies further support our data analysis pointing towards preferential/selective roles for <italic>NR4A2</italic> in the regulation of antigen processing with common roles for <italic>NR4A2</italic> and <italic>NR4A3</italic> evident with respect to cell migration. Taken together this study provides novel mechanistic insights into the role of the enigmatic nuclear receptors NR4A2 and NR4A3 in monocytes.</p>