Epigenetic Reprogramming via TET2 Prevents Medial Calcification and Restores Vascular Smooth Muscle Cell Identity.

Area of Science:

• Epigenetics
• Vascular Biology
• Cardiovascular Disease

Background:

• Vascular calcification is a hallmark of cardiovascular pathologies, stemming from the osteogenic transdifferentiation of vascular smooth muscle cells (VSMCs).
• Epigenetic modifications play a crucial role in regulating VSMC phenotype and vascular calcification.
• Tet2, a DNA demethylase, is implicated in epigenetic regulation but its role in vascular calcification requires further elucidation.

Purpose of the Study:

• To investigate the role of Tet2 as an epigenetic regulator in preventing VSMC osteogenic transdifferentiation and vascular calcification.
• To determine the effect of Tet2 loss on VSMC phenotype and aortic calcification.
• To evaluate the therapeutic potential of enhancing Tet2 activity in mitigating vascular calcification.

Main Methods:

• Generated VSMC-specific Tet2 knockout mouse models.
• Assessed VSMC differentiation, apoptosis, and macrophage infiltration in knockout mice.
• Quantified medial aortic calcification and analyzed aortic structure.
• Administered high-dose ascorbate to wild-type mice to enhance Tet2 activity and evaluated its effects on calcification.

Main Results:

• Loss of Tet2 in VSMCs promoted osteogenic differentiation and apoptosis.
• Tet2 deficiency led to increased infiltration of Trem2-high macrophages and significant medial aortic calcification.
• High-dose ascorbate administration significantly reduced vascular calcification and preserved aortic structure in mice.
• Tet2 activity was identified as a critical epigenetic mechanism preventing VSMC transdifferentiation.

Conclusions:

• Tet2 is a critical epigenetic regulator that prevents the osteogenic transdifferentiation of VSMCs, thereby inhibiting vascular calcification.
• Tet2 deficiency exacerbates vascular calcification and associated pathologies.
• Enhancing Tet2 activity, for example, through high-dose ascorbate, represents a promising therapeutic strategy for preventing or reversing vascular calcification in cardiovascular disease.