Transcription factor TBX2 is a key regulator of vascular calcification.

Background

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Aims

Vascular calcification predicts cardiovascular mortality more strongly than traditional risk factors, yet its molecular basis remains poorly understood. The burden is greatest in chronic kidney disease (CKD), where disordered mineral metabolism accelerates arterial mineral deposition.

Methods

Cross-trait genome-wide and phenome-wide association analyses were combined with single-cell RNA-seq and ATAC-seq from human kidneys and coronary arteries to identify upstream regulators. Chromatin immunoprecipitation sequencing and expression profiling were used to assess direct transcriptional control. Functional relevance was evaluated in multiple gene-edited mouse lines and in primary vascular smooth muscle cells (VSMCs) targeting T-box transcription factor 2 (TBX2), Runt-related transcription factor 2 (RUNX2), NLRP3, CASP1, and GSDMD.

Results

GWAS followed by expression quantitative trait loci (eQTL) and Bayesian colocalization analysis prioritized TBX2 as a shared genetic locus associated with kidney function and calcification-related cardiometabolic traits. TBX2-deficient mice exhibited increased susceptibility to vascular calcification, hypercalciuria, kidney injury, bone demineralization, and systemic phosphate dysregulation under CKD-like phosphate stress conditions. TBX2 deficiency promoted VSMC calcification and osteochondrogenic differentiation in vitro. Mechanistically, TBX2 acted as a transcriptional repressor by binding the promoter of RUNX2, a key osteogenic transcription factor, and suppressing its expression. Deletion of RUNX2 in TBX2-deficient VSMCs abolished TBX2 loss-induced calcification. TBX2-deficient VSMCs were also more sensitive to activation of the NLRP3 inflammasome by microcrystals generated from osteogenic VSMCs. Genetic deletion of NLRP3, CASP1, or GSDMD in TBX2-deficient mice attenuated vascular calcification and renal injury. In human samples, TBX2 expression inversely correlated with the severity of kidney fibrosis and was reduced in calcified vascular lesions.

Conclusions

Integrative genetic, cellular, and animal studies identify TBX2 as a central transcriptional repressor linking mineral dysregulation, osteogenic signalling, and sterile inflammation in CKD-associated vascular calcification. Therapeutic strategies that restore TBX2 function or target its RUNX2-NLRP3 axis may reduce cardiovascular risk in patients with CKD.