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.