Poster Presentation 44th Lorne Genome Conference 2023

METTL3-dependent m6A RNA methylation regulates inflammasome activation (#264)

Natalia Pinello 1 2 , Quintin Lee 1 2 , Xi Yang 3 , Xing Huang 4 , Zhouli Chen 4 , Renhua Song 1 2 , Chinh Ngo 5 , Jessica Tieng 1 2 , Mark Larance 6 , Fei Lan 7 , Ben Roediger 8 , Jocelyn Widagdo 9 , Victor Anggono 9 , Oliver Rausch 10 , Yaara Ofir-Rosenfeld 10 , Jeffrey Chaitow 11 , Davinder Singh-Grewal 11 , Si Ming Man 5 , Xiangjian Zheng 3 , Dan Ye 4 , Justin J-L Wong 1 2
  1. Epigenetics and RNA Biology Program, Centenary Institute, Sydney, NSW, Australia
  2. Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
  3. Department of Pharmacology, Tianjin Medical University, Tianjin, China
  4. The Molecular and Cell Biology Lab, Fudan University, Shanghai, China
  5. Department of Immunology and Infectious Disease, The Australian National University, Canberra, Australia
  6. Charles Perkins Centre, The University of Sydney, Sydney, Australia
  7. Key Laboratory of Medical Epigenetics, Fudan University, Shanghai, China
  8. Skin Inflammation Group, Centenary Institute, Sydney, Australia
  9. Clem Jones Centre for Ageing Dementia Research, University of Queensland, Brisbane, Australia
  10. STORM Therapeutics, Cambridge, UK
  11. Sydney Children’s Hospital Westmead, Sydney, Australia

N6-methyladenosine (m6A) that results from methylation of adenosine residues by the METTL3-METTL14 methyltransferase complex mediates essential processes on RNA including splicing, mRNA decay and translation.  m6A has emerged as a key regulator of fundamental cellular processes. However, its roles in the immune response are largely unknown. The NLRP3 inflammasome is a cytosolic sensor that upon recognition of danger signals fires the innate immune response. NLRP3 mediates caspase-1-dependent maturation and release of the pro-inflammatory cytokines IL-1b and IL-18 and lytic cell death. While a broad range of pathogens can activate the NLRP3 inflammasome, in most cases, it appears to be dispensable to fight infection. Given that NLRP3 activation has been identified as a driver of numerous inflammatory disorders, considerable efforts have been invested to understand the molecular mechanisms behind the NLRP3 pathway. However, the role of RNA modifications in inflammasome activation is not as yet reported. In this study, we discovered that METTL3 is essential for activation of the NLRP3 inflammasome in vitro and in vivo. Pharmacological inhibition of METTL3 attenuated NLRP3 hyperactivation in blood cells isolated from patients suffering from a disease caused by NLRP3 gain-of-function mutations called Cryopyrin-associated Periodic Syndromes. Furthermore, METTL3 ablation in the myeloid compartment rendered mice resistant to NLRP3-mediated endotoxic shock. Mechanistically, we identified NLRP3 amongst METTL3 direct targets in macrophages, and found that METTL3 regulates NLRP3 gene expression at two levels: i) co-transcriptionally, promoting H3K9me2 demethylation nearby NLRP3 promoter; and ii) promoting NLRP3 translation via action of the m6A reader protein, YTHDF1. Our work places m6A-mediated regulation of gene expression at the centre of immunity and brings forward METTL3 and YTHDF1 as novel potential targets for therapeutic intervention in inflammation-driven syndromes.