Immunoactive signatures of circulating tRNA- and rRNA-derived RNAs in chronic obstructive pulmonary disease

Abstract

Chronic obstructive pulmonary disease (COPD) is the most prevalent lung disease, and macrophages play a central role in the inflammatory response in COPD. We here report a comprehensive characterization of circulating short non-coding RNAs (sncRNAs) in plasma from patients with COPD. While circulating sncRNAs are increasingly recognized for their regulatory roles and biomarker potential in various diseases, the conventional RNA sequencing (RNA-seq) method cannot fully capture these circulating sncRNAs due to their heterogeneous terminal structures. By pre-treating the plasma RNAs with T4 polynucleotide kinase, which converts all RNAs to those with RNA-seq susceptible ends (5′-phosphate and 3′-hydroxyl), we comprehensively sequenced a wide variety of non-microRNA sncRNAs, such as 5′-tRNA halves containing a 2′,3′-cyclic phosphate. We discovered a remarkable accumulation of the 5′-half derived from tRNAValCAC in plasma from COPD patients, whereas the 5′-tRNAGlyGCC half is predominant in healthy donors. Further, the 5′-tRNAValCAC half activates human macrophages via Toll-like receptor 7 and induces cytokine production. Additionally, we identified circulating rRNA-derived fragments that were upregulated in COPD patients and demonstrated their ability to induce cytokine production in macrophages. Our findings provide evidence of circulating, immune-active sncRNAs in patients with COPD, suggesting that they serve as inflammatory mediators in the pathogenesis of COPD. Chronic obstructive pulmonary disease (COPD) is the most prevalent lung disease, and macrophages play a central role in the inflammatory response in COPD. We here report a comprehensive characterization of circulating short non-coding RNAs (sncRNAs) in plasma from patients with COPD. While circulating sncRNAs are increasingly recognized for their regulatory roles and biomarker potential in various diseases, the conventional RNA sequencing (RNA-seq) method cannot fully capture these circulating sncRNAs due to their heterogeneous terminal structures. By pre-treating the plasma RNAs with T4 polynucleotide kinase, which converts all RNAs to those with RNA-seq susceptible ends (5′-phosphate and 3′-hydroxyl), we comprehensively sequenced a wide variety of non-microRNA sncRNAs, such as 5′-tRNA halves containing a 2′,3′-cyclic phosphate. We discovered a remarkable accumulation of the 5′-half derived from tRNAValCAC in plasma from COPD patients, whereas the 5′-tRNAGlyGCC half is predominant in healthy donors. Further, the 5′-tRNAValCAC half activates human macrophages via Toll-like receptor 7 and induces cytokine production. Additionally, we identified circulating rRNA-derived fragments that were upregulated in COPD patients and demonstrated their ability to induce cytokine production in macrophages. Our findings provide evidence of circulating, immune-active sncRNAs in patients with COPD, suggesting that they serve as inflammatory mediators in the pathogenesis of COPD.

Topics & Concepts