Targeting SETD7 Rescues Diabetes-Induced Impairment of Angiogenic Response by Transcriptional Repression of...

Revascularization strategies failed to improve outcome in patients with diabetes with peripheral artery disease (PAD). Histone modifications are key modulators of gene expression and could play a role in angiogenic response. This study investigates the role of chromatin remodelling in modulating angiogenesis in diabetes. RNA sequencing (RNA-seq), and angiogenic assays (cell migration and tube formation) were performed in human aortic endothelial cells (HAECs) exposed to normal glucose (NG, 5 mmol/L) or high glucose (HG, 25 mmol/L) for 48 h. The expression of the histone methyltransferase SETD7 and its chromatin signature at histone 3 on lysine 4 (H3K4me1) were investigated by Western blot and chromatin immunoprecipitation (ChIP). Diabetic mice were treated with the SETD7 inhibitor (R)-PFI-2 or vehicle and underwent hind limb ischemia by femoral artery ligation. The experimental findings were translated into two cohorts of patients with diabetes with PAD. RNA-seq in HG-treated HAECs unveiled SETD7 as the top-ranking transcript. SETD7 upregulation was associated with increased H3K4me1 levels and defective angiogenesis. Both SETD7 depletion and (R)-PFI-2 rescued hyperglycemia-induced impairment of HAECs migration and tube formation, while SETD7 overexpression blunted the angiogenic response. RNA-seq and ChIP assays showed that SETD7-induced H3K4me1 enables the transcription of the angiogenesis inhibitor semaphorin-3G (SEMA3G) by increasing chromatin accessibility to peroxisome proliferator-activated receptor-γ. In diabetic mice with hind limb ischemia, (R)-PFI-2 improved limb perfusion by suppressing SEMA3G. The SETD7/SEMA3G axis was upregulated in patients with diabetes with PAD. Of note, (R)-PFI-2 restored angiogenic properties in endothelial cells collected from patients with diabetes. These findings show that SETD7 is a druggable epigenetic target in diabetic PAD.

Hyperglycemia increases SETD7 expression and SETD7-dependent histone 3 on lysine 4, thus leading to an open chromatin and active transcription of the antiangiogenic gene semaphorin-3G (SEMA3G). Gene silencing and selective pharmacological inhibition of SETD7 by (R)-PFI-2 both blunt histone 3 on lysine 4 levels and SEMA3G transcription, thus rescuing hyperglycemia-induced impairment of angiogenic properties. The SETD7 inhibitor (R)-PFI-2 promotes neovascularization and restores limb perfusion in diabetic mice. SETD7/SEMA3G signaling was dysregulated in two different cohorts of patients with diabetes with peripheral arterial disease. Treatment with (R)-PFI-2 in endothelial cells collected from patients with diabetes restores angiogenic properties.