Mechanosensitive snoRNA-like circular RNA sno-circCNOT1 drives endothelial dysfunction and atherosclerosis

<b>Rationale:</b> Hemodynamic shear stress critically influences atherosclerosis progression, yet the molecular mechanisms linking biomechanical stimuli to endothelial activation and vascular pathology remain poorly understood. While circular RNAs (circRNAs) participate in endothelial mechanotransduction, the role of mechanosensitive small nucleolar RNA (snoRNA)-like circRNA-a unique subclass harboring snoRNA sequences-in atherosclerosis is unexplored. <b>Methods:</b> We characterized sno-circCNOT1 using high-throughput RNA sequencing, RNA interference, immunofluorescence, and co-immunoprecipitation. Functional studies were performed in endothelial cells and <i>ApoE⁻/⁻</i> mice to assess its role in pyroptosis and atherogenesis. Mechanistic investigations included RNA pull-down, mass spectrometry, and gain- and loss-of-function assays to identify sno-circCNOT1-interacting proteins and downstream signaling. <b>Results:</b> We identified sno-circCNOT1, a circular RNA derived from <i>CNOT1</i> exon 17 and intron 17, which incorporates snoRNA SNORA50A. Its expression was upregulated by pro-atherogenic interleukin-1β and pathological oscillatory shear stress, but downregulated by laminar shear stress. Functionally, sno-circCNOT1 mediated shear stress-dependent regulation of endothelial pyroptosis and inflammation. Endothelial-specific overexpression of sno-circCNOT1 aggravated atherosclerotic lesion formation in <i>ApoE⁻/⁻</i> mice. Mechanistically, its snoRNA-like motif was essential for nuclear localization and function. sno-circCNOT1 bound the IF-ROD domain of lamin A/C (LMNA), stabilizing LMNA and facilitating its interaction with the N-terminal domain of methyltransferase-like 14 (METTL14-N), thereby enhancing METTL14 stability. This axis activated NOD-like receptor protein 3 (NLRP3) and amplified endothelial inflammation. Conversely, overexpression of METTL14-N to disrupt this signaling axis attenuates endothelial dysfunction and atherosclerosis progression. <b>Conclusions:</b> sno-circCNOT1 is a mechanosensitive snoRNA-like circRNA that promotes endothelial pyroptosis and atherogenesis via the LMNA/METTL14/NLRP3 axis. METTL14-N offers a protein-based therapeutic approach, positioning this regulatory pathway as a druggable target for atherosclerosis.