Twist1 promoting neointima hyperplasia after vascular injury in diabetes via regulating hyperglycemia-induced phenotype switching of vascular smooth muscle cells.

BACKGROUND AND AIMS: Neointimal hyperplasia is a key pathology in Type 2 Diabetes Mellitus (T2DM) vascular complications. It involves phenotypic switching of vascular smooth muscle cells (VSMCs) triggered by hyperglycemia, though the exact mechanisms remain unclear.

METHODS

We employed Twist1 vascular smooth muscle-specific knockout mice with carotid artery ligation in a T2DM model to study Twist1's role in diabetic neointimal hyperplasia. In vitro, we examined how hyperglycemia via Pkcβ/Ikkβ/Nf-κb pathway affects Twist1's regulation of contractile proteins, matrix molecules, cell morphology, migration, and proliferation in rat VSMCs using Western blotting, immunofluorescence, wound healing assays, and EdU incorporation. Co-immunoprecipitation and colocalization assessed how Twist1-p300 interaction under high glucose affects Myocardin-Srf binding.

RESULTS

Twist1 was significantly upregulated in VSMCs of T2DM mice. Vascular smooth muscle-specific Twist1 knockout reduced neointimal formation after vascular injury in T2DM. High glucose activated Pkcβ/Ikkβ/Nf-κb pathway, promoting Twist1 upregulation and nuclear translocation, decreasing contractile protein expression while increasing matrix molecules and VSMC proliferation/migration. Mechanistically, upregulated Twist1 increased p300 binding, blocking p300's transcriptional co-activation of Myocardin/Srf and inhibiting contractile gene transcription in VSMCs.

CONCLUSIONS

Hyperglycemia activates the PKCβ/IKKβ/NF-κB pathway, upregulating Twist1 and promoting its nuclear translocation. Twist1 binding to p300 inhibits Myocardin/SRF-mediated contractile gene transcription, leading to VSMC phenotypic switching and neointimal hyperplasia. These findings highlight Twist1 as a potential therapeutic target for diabetic vascular complications.