Chronic Electronic Cigarette Exposure Promotes Atherosclerosis and Chondrogenic Modulation of Smooth Muscle Cells

BackgroundElectronic cigarette (E-cig) use has reached epidemic proportions worldwide, yet its cardiovascular consequences remain poorly defined. While several lines of evidences in human epidemiological and animal studies suggest chronic aerosol exposure accelerates atherosclerosis; the cellular and molecular mechanisms underlying this pathological remain unknown. MethodsWe exposed hyperlipidemic mice to chronic e-cigarette aerosol inhalation and characterized the plaque cellular landscape by coupling SMC lineage tracing with single-cell transcriptomic/epigenomic profiling and histologic phenotyping. We subsequently leveraged human coronary artery smooth muscle cells (HCASMCs) to validate in vivo discovery and identified E-cig specific pathological signaling pathways relevant to human vascular disease risk. ResultsChronic E-cig aerosol exposure accelerated atherosclerosis, increasing both SMC phenotypic modulation and plaque macrophage burden in a lipid-independent manner. Transcriptomically, SMCs are particularly more sensitive to E-cig than other vascular cell types. E-cig exposure reprogrammed SMCs toward a pro-calcifying, chondrogenic phenotype, thereby enhancing vascular ossification in vivo and in HCASMCs in vitro. Mechanistically, E-cig mediated SMC fate alteration occurs through activation of a glutamatergic/NMDAR signaling program, that increased NMDAR-dependent Ca2+ influx in a GRIN2A dependent manner. Notably, inhibition of GRIN2A mediated signaling reversed E-cig-induced pathological shifts in SMC phenotype. ConclusionsSMC chondrogenic reprogramming and subsequent vascular calcification are central to the detrimental cardiovascular consequences of E-cig exposure. Our findings implicate a GRIN2A-dependent glutamatergic/NMDAR signaling axis in SMC as a primary driver of this calcifying remodeling program. These findings define a SMC-specific vulnerability to E-cig aerosols and establish the GRIN2A/NMDAR pathway as potential therapeutic targets for mitigating E-cig-associated cardiovascular disease.