A 5′ tRNA-derived fragment tDR-Glu-TTC exacerbates intestinal ischemia/reperfusion injury via ADAR1/autophagy/ROS/necroptosis signaling axis

Transfer RNA-derived small RNAs (tDRs) are a class of functional small non-coding RNAs, many of which are induced by stress conditions and have been implicated in tissue injury and disease pathogenesis. However, their role in intestinal ischemia/reperfusion (I/R) injury remains unclear. Using tDR sequencing, we identified that tDR-Glu-TTC was significantly upregulated in intestinal tissues, plasma, epithelial cells, and human clinical samples; and its levels positively correlated with the severity of intestinal injury. Functionally, tDR-Glu-TTC exacerbates intestinal mucosal damage by activating TNF pathway - mediated necroptosis in intestinal epithelial cells. Mechanistically, tDR-Glu-TTC directly binds to and suppresses the RNA-editing enzyme ADAR1, impairing adenosine-to-inosine editing of autophagy-related transcripts (ATG18 and Lamp2). This inhibits autophagy, leading to the accumulation of damaged mitochondria, and the release of reactive oxygen species (ROS). The elevated ROS subsequently promotes TNF-α secretion, triggering TNF pathway-mediated necroptosis. Furthermore, increased ROS downregulates TRMT6/61A-dependent m¹A methylation of tRNA-Glu-TTC, increasing tDR-Glu-TTC biogenesis and forming a pathogenic positive feedback loop. Thus, therapeutic dual-target intervention using N-acetylcysteine combined with tDR-Glu-TTC-antagomir synergistically mitigated I/R - induced intestinal injury in vivo. In summary, our study unveiled a previously unrecognized mechanism by which tDR-Glu-TTC exacerbates intestinal I/R injury via the ADAR1/autophagy/ROS/necroptosis signaling axis, offering a promising therapeutic strategy for combating intestinal I/R injury.