Inhibition of pro-inflammatory signaling in human primary macrophages by enhancing arginase-2 via target site blockers

Stephen Fitzsimons; María Muñoz-San Martín; Frances Nally; Eugene Dillon; Ifeolutembi A Fashina; Moritz J Strowitzki; Lluís Ramió-Torrentà; Jennifer K Dowling; Chiara De Santi; Claire E McCoy

doi:10.1016/j.omtn.2023.08.023

Inhibition of pro-inflammatory signaling in human primary macrophages by enhancing arginase-2 via target site blockers

Mol Ther Nucleic Acids. 2023 Aug 22:33:941-959. doi: 10.1016/j.omtn.2023.08.023. eCollection 2023 Sep 12.

Authors

Affiliations

¹ School of Pharmacy and Biomolecular Science, Royal College of Surgeons in Ireland, 123 St Stephen's Green, Dublin 2, Ireland.
² FutureNeuro, SFI Research Centre for Chronic and Rare Neurological Diseases, Royal College of Surgeons in Ireland, 123 St. Stephen's Green, Dublin 2, Ireland.
³ School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland.
⁴ Department of General, Visceral & Transplantation Surgery, University Hospital Heidelberg, Heidelberg, Germany.
⁵ Neuroinflammation and Neurodegeneration Group, Girona Biomedical Research Institute (IDIBGI), CERCA Programme/Generalitat de Catalunya, Salt, Girona, Spain.

Abstract

The modulation of macrophage phenotype from a pro-inflammatory to an anti-inflammatory state holds therapeutic potential in the treatment of inflammatory disease. We have previously shown that arginase-2 (Arg2), a mitochondrial enzyme, is a key regulator of the macrophage anti-inflammatory response. Here, we investigate the therapeutic potential of Arg2 enhancement via target site blockers (TSBs) in human macrophages. TSBs are locked nucleic acid antisense oligonucleotides that were specifically designed to protect specific microRNA recognition elements (MREs) in human ARG2 3' UTR mRNA. TSBs targeting miR-155 (TSB-155) and miR-3202 (TSB-3202) MREs increased ARG2 expression in human monocyte-derived macrophages. This resulted in decreased gene expression and cytokine production of TNF-α and CCL2 and, for TSB-3202, in an increase in the anti-inflammatory macrophage marker, CD206. Proteomic analysis demonstrated that a network of pro-inflammatory responsive proteins was modulated by TSBs. In silico bioinformatic analysis predicted that TSB-3202 suppressed upstream pro-inflammatory regulators including STAT-1 while enhancing anti-inflammatory associated proteins. Proteomic data were validated by confirming increased levels of sequestosome-1 and decreased levels of phosphorylated STAT-1 and STAT-1 upon TSB treatment. In conclusion, upregulation of Arg2 by TSBs inhibits pro-inflammatory signaling and is a promising novel therapeutic strategy to modulate inflammatory signaling in human macrophages.

Keywords: MT: Oligonucleotides: Therapies and Applications; arginase-2; inflammation; macrophages; miR-155; microRNA; multiple sclerosis; target site blockers.