Biological functions of tsRNAs and research advances in human disease.

tsRNAs (tRNA-derived small RNAs) are a class of noncoding small RNAs generated by nuclease-specific cleavage of mature tRNAs or their precursors. Since their functional discovery in 2009, tsRNAs have emerged as a research hotspot in molecular biology and medicine because of their unique generation mechanism, tissue-specific expression patterns, and diverse regulatory functions. Compared with traditional non-coding RNAs (such as miRNAs and lncRNAs), tsRNAs exhibit distinct biological activities in stress responses, translational regulation, and epigenetic modifications and are closely associated with the onset and progression of various human diseases. This systematic review covers the discovery history, classification characteristics, primary biological functions, and action mechanisms of tsRNAs in major diseases, including respiratory disorders, neuropsychiatric conditions, cardiovascular diseases, and tumors. It further explores the clinical translational potential of tsRNAs as disease biomarkers and therapeutic targets, identifies current challenges, and outlines future research directions. Major knowledge gaps highlighted include the lack of standardized detection methods for tsRNA subtypes, unclear specificity of their molecular targets in pathological processes, and limited validation in large clinical cohorts; key challenges involve inefficient delivery of tsRNA-based therapeutics and insufficient exploration of cross-species conservation. The review aims to provide a comprehensive reference for in-depth studies in the field of tsRNA.