Project description:High-throughput small RNA sequencing (sRNA-seq) has facilitated many discoveries, but extracellular sRNA (ExRNA) present unique analytical challenges that are not met by current software. Therefore, we developed a novel data analysis pipeline entitled, “TIGER”, which caters to exRNA. To demonstrate the power of this tool, sRNA-seq was performed on high-density lipoproteins (HDL), apolipoprotein B particles (APOB), bile, urine, and liver samples. TIGER was able to characterize approximately 60% of lipoprotein, and >85% of liver, bile, and urine sRNA-seq depth, a significant advance compared to existing software. A key advance for the TIGER pipeline is the ability to analyze host and non-host sRNAs at genomic, parent RNA, and individual fragment levels. Results suggest that the majority of sRNAs on lipoproteins are derived from bacterial sources in the microbiome and environment. Collectively, TIGER facilitated novel discoveries of lipoprotein and biofluid sRNAs and has tremendous applicability for the field of exRNA.