Inhibition of long interspersed nuclear element-1 by nucleoside reverse transcriptase inhibitors attenuates vascular calcification

Vascular calcification (VC) is a critical vascular pathological event, contributing to the rise in both the prevalence and fatality of cardiovascular diseases. However, the lack of effective therapeutic strategies for VC is attributed primarily to the incomplete understanding of its underlying molecular mechanisms. In this study, we discovered that long interspersed nuclear element 1 (LINE1) was significantly upregulated in the calcified arteries of both human individuals and mouse models. Mechanistically, silencing LINE1 expression or inhibiting its activity with adding nucleoside Reverse Transcriptase inhibitors (NRTIs, a class of validated LINE1 inhibitors) effectively prevented the osteogenic reprogramming of vascular smooth muscle cells (VSMCs). Moreover, NRTIs treatment substantially mitigated VC in chronic kidney disease (CKD)-induced and vitamin D₃-overloaded VC mouse models. RNA Sequencing analysis revealed that LINE1 depletion (via small interfering RNA) or NRTIs intervention downregulated the cGAS-STING signaling pathway and its associated inflammatory genes in VSMCs. Functional validation revealed that stimulation of the cGAS‒STING pathway exacerbated VC, whereas its pharmacological inhibition alleviated VC. Notably, we identified LINE1-derived cDNA as a direct activator of the cGAS‒STING pathway, demonstrating that LINE1 inhibition suppresses VC by blocking cGAS‒STING activation and subsequent inflammatory responses. Clinically, a cross-sectional study involving 1,785 participants revealed that patients receiving NRTIs therapy presented a significantly lower incidence of VC and reduced calcification scores. Multivariate logistic regression analysis further confirmed that NRTIs use is an independent protective factor against VC incidence and progression. Collectively, these findings establish LINE1 as promising therapeutic targets for VC and highlight NRTIs as potential candidates for developing novel strategies against VC.