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

TL;DR

A specific circular RNA, sno-circCNOT1, is shown to promote atherosclerosis by linking biomechanical stress to inflammation and cell death in blood vessels.

Contribution

The discovery of sno-circCNOT1 as a mechanosensitive snoRNA-like circRNA that drives atherosclerosis through a novel LMNA/METTL14/NLRP3 pathway.

Findings

sno-circCNOT1 is upregulated by pro-atherogenic stress and interleukin-1β, and downregulated by laminar shear stress.

sno-circCNOT1 promotes endothelial pyroptosis and atherosclerosis by stabilizing LMNA and enhancing METTL14-N activity.

Disrupting the LMNA/METTL14/NLRP3 axis reduces endothelial dysfunction and atherosclerosis progression.

Abstract

Rationale: 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.

Methods: We characterized sno-circCNOT1 using high-throughput RNA sequencing, RNA interference, immunofluorescence, and co-immunoprecipitation. Functional studies were performed in endothelial cells and ApoE⁻/⁻ 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.

Results: We identified sno-circCNOT1, a circular RNA derived from CNOT1 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 ApoE⁻/⁻ 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.

Conclusions: 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.

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