GEOGenomicsMus musculusNon-coding RNA profiling by high throughput sequencinghttps://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE328570GEOGSEfalseI-tRF-Asp promotes vascular remodeling in hypoxic pulmonary hypertension via hnRNPU phase separation which affects TCF7L2 alternative splicing.BACKGROUND: Pulmonary hypertension (PH) is a fatal disease characterized by pulmonary vascular remodeling, primarily driven by excessive proliferation of pulmonary arterial smooth muscle cells (PASMCs). While non-coding RNAs such as circular RNAs have been implicated in PH, the role of tRNA-derived small RNA (tsRNA) remains poorly understood. Among them, i-tRF-Asp represents a novel tsRNA whose function in hypoxic PH is unknown. This study aims to investigate whether i-tRF-Asp contributes to PASMC proliferation and vascular remodeling in hypoxic PH. METHODS: To elucidate the functional role of i-tRF-Asp, loss-of-function experiments were conducted in vitro using hypoxic mouse PASMCs (mPASMCs), alongside in vivo studies utilizing both SuHx (Sugen5416+hypoxia) induced pulmonary hypertension models in both adult male C57BL/6 mice and Sprague-Dawley rats. These models employed antisense oligonucleotide inhibitor and adeno-associated virus-mediated silencing. The underlying mechanisms were further explored via RNA immunoprecipitation, liquid-liquid phase separation assays, cell proliferation assessment, western blot, alternative splicing profiling and molecular dynamics simulation. RESULTS: Inhibition of i-tRF-Asp ameliorated hypoxia-induced pulmonary vascular remodeling, primarily through suppressing excessive proliferation of mPASMCs. Further analysis indicated that i-tRF-Asp facilitates liquid–liquid phase separation (LLPS) of hnRNPU. This process mediates selective recruitment of Tcf7l2 pre-mRNA and promotes alternative splicing, resulting in a pro-proliferative Tcf7l2 transcript variant that drives mPASMC proliferation. Furthermore, we have identified that the endonuclease ERN1 can upregulate the expression of i-tRF-Asp. CONCLUSION: The endoribonuclease ERN1 upregulates the expression of i-tRF-Asp, which in turn facilitates mPASMC proliferation and pulmonary vascular remodeling. This process is driven by hnRNPU LLPS-dependent alternative splicing of the long Tcf7l2 transcript isoform.2026/06/03GSE328570GSM9685476GSM9685475GSM9685474GSM9685473GSM9685472GSM968547121626328570Mus musculus[42206368]