Abstract Body: Vascular Smooth Muscle Cell (VSMC) phenotypic switching is a central driver of atherosclerosis, restenosis, and vascular pathology. While PTEN is classically recognized for its role in PI3K/AKT signaling and maintenance of the contractile phenotype, the transcriptional mechanisms underlying its regulatory effects remain incompletely defined. Here, we investigated a functional interaction between PTEN and Kruppel-like factor 4 (KLF4), a key transcription factor implicated in VSMC dedifferentiation.
We demonstrate that PTEN forms a protein complex with KLF4 in VSMCs under basal serum-arrested conditions, and that inflammatory and proliferative stimulation with PDGF induces a dissociative state. Co-immunoprecipitation and proximity ligation assays confirm a direct interaction between PTEN and KLF4, which becomes dysregulated upon PDGF stimulation. Mechanistically, PTEN inhibits KLF4 nuclear localization and transcriptional activity, resulting in suppression of synthetic phenotype gene programs while preserving contractile marker expression, including Mhy11 and Acta2. Inhibitory studies of DNMT1 and PI3K using 5′-azacytidine and LY294002, respectively, reveal increased KLF4-driven transcriptional reprogramming upon PDGF stimulation, characterized by elevated proliferative gene expression. Interestingly, 5′-azacytidine, which we previously demonstrated results in PTEN induction, was able to reverse PDGF-mediated phosphorylated KLF4 protein expression, an effect not observed with PI3K inhibition alone.
Functionally, disruption of the PTEN–KLF4 complex accelerates VSMC phenotypic switching, whereas restoration of PTEN activity stabilizes the contractile state. These findings suggest that PTEN exerts non-canonical regulatory control over VSMC phenotype through direct interaction with KLF4, thereby bridging signaling and transcriptional networks.
This study identifies a PTEN–KLF4 axis as a critical checkpoint in vascular disease progression and highlights its potential as a therapeutic target for preventing pathological vascular remodeling. Future work will mechanistically explore KLF4 and PTEN synergy in maintaining normal vascular homeostasis.