ATF4 transcriptional regulation of OMD and STC2 drives vascular calcification progression via the PI3K/AKT pathway

Vascular calcification (VC) is a pathological process characterized by the deposition of calcium phosphate crystals in blood vessels. Despite its clinical significance, the molecular mechanisms underlying VC remain poorly understood. This study integrated transcriptomic data from public datasets and experimental models to identify key regulators of VC. Human aortic smooth muscle cells (HASMCs) were induced to calcify using osteogenic medium (OM), followed by transcriptomic sequencing. Differential gene expression, functional enrichment, and machine learning-based hub gene identification, were performed. Experimental validation was conducted using in vitro and in vivo models. Transcriptomic analysis identified 278 differentially expressed genes (DEGs), 45 of which were associated with metabolism. Bioinformatic and machine learning approaches highlighted Osteomodulin (OMD), and Stanniocalcin 2 (STC2) as key regulators of VC. The iRegulon tool predicted that OMD and STC2 share a common transcription factor Activating Transcription Factor 4 (ATF4). In calcified human vascular tissues, ATF4, OMD, and STC2 expression levels were significantly upregulated, correlating with increased calcification markers such as RUNX2, ALP, and OCN. Functional studies demonstrated that ATF4 transcriptionally upregulates OMD and STC2 by binding to their promoter regions, then activated the PI3K/AKT signaling pathway, promoting osteogenic differentiation in HASMCs. In vivo experiments using AAV-SM22α-shATF4 confirmed that targeting ATF4 alleviates VC by suppressing OMD and STC2 expression and reducing calcium deposition. In conclusion, our study reveals that ATF4 promotes vascular calcification by transcriptionally upregulating OMD and STC2,which in turn activates the PI3K/AKT signaling pathway. These findings provides new evidence for the direct regulatory relationship between signaling nodes in the field of VC signaling network.