Ro60 - Roles in RNA Processing, Inflammation, and Rheumatic Autoimmune Diseases

The Ro60 autoantigen is an RNA-binding protein, and a core component of nucleocytoplasmic ribonucleoprotein (RNP) complexes. Ro60 is essential in RNA metabolism, cell stress response pathways, and cellular homeostasis. It stabilises and mediates quality control and cellular dis-tribution of YRNAs, retroelement transcripts, and misfolded RNAs. Ro60 transcriptional dysregulation or loss of function can result in the generation and release of RNA fragments from YRNAs and other small RNAs. Small RNA fragments can instigate an inflammatory cascade through endosomal TLRs and cytoplasmic RNA sensors, which typically sense patho-gen-associated molecular patterns (PAMPs) and mount the first line of defence against invading pathogens. However, recognition of host-originating RNA moieties from Ro60 RNP complexes can activate inflammatory response pathways and compromise self-tolerance. Autoreactive B cells may produce antibodies targeting extracellular Ro60 RNP complexes. Ro60 autoantibodies serve as diagnostic markers for various autoimmune diseases including Sjögren's disease (SjD) and systemic lupus erythematosus (SLE), and they may also act as predictive markers for an-ti-drug antibody response among rheumatic patients. Understanding Ro60’s structure, function, and role in self-tolerance can enhance our understanding of the underlying molecular mecha-nisms of autoimmune conditions.