Abstract Th0027: LncRNA <i>LINC02861</i> promotes cellular senescence in human vascular smooth muscle cells

Long noncoding RNAs (lncRNAs) are poorly characterized transcripts (&gt; 200 nucleotides in length) that interact with several macromolecules, including DNA, RNA, and RNA binding proteins (RBPs), to regulate gene expression and cellular processes. Notably, accumulation of senescent cells, a state of persistent cell cycle arrest with increased production of inflammatory factors, in tissues is a hallmark of aging and often features dysregulated lncRNAs. Here, we employed long-read RNA sequencing to identify lncRNAs associated with human vascular smooth muscle cell (hVSMC) senescence. HVSMCs were rendered senescent using doxorubicin or ionizing radiation, and the expression profile of lncRNAs was assessed. We then identified the top 10 statistically significant upregulated lncRNAs, including 7 annotated and 3 novel lncRNAs. Next, we validated their abundance using RT-qPCR of senescent hVSMCs and performed cell fractionation to identify the localization of our lncRNAs in senescent compared to proliferating cells. Fractionation results revealed a subset of lncRNAs that translocate upon induction of senescence which can suggest changes in function based on the new localization. We then considered lncRNAs that were highly upregulated and translocated in senescent VSMCs and employed antisense oligonucleotides (ASOs) to efficiently knockdown each target lncRNA and determine their functional impact. Among the tested lncRNAs, knockdown of LINC02861 promoted cell proliferation thus suggesting that LINC02861 is required for cell cycle inhibition during senescence progression. We then utilized RT-qPCR analysis and found that upon LINC02861 knockdown, the expression of known markers of cellular senescence ( CDKN2A and GDF15 mRNA) decreased. Based on the Open Targets platform, we identified high expression of LINC02861 in the vasculature, including but not limited to the aorta, coronary and tibial artery, and other tissues of the heart. We hypothesize that lncRNA LINC02861 is a vascular-specific lncRNA that promotes vascular aging and age-related diseases such as atherosclerosis by facilitating senescence. In our future studies, we will measure the levels of these lncRNAs in human samples of healthy and disease vascular tissue, identify the lncRNA’s evolutionary conserved counterparts in mice, and determine whether targeting LINC02861 or its downstream effectors provides an opportunity to ameliorate age-related decline and diseases of the vasculature.