Targeting SETD7 Rescues Diabetes-Induced Impairment of Angiogenic Response by Transcriptional Repression of Semaphorin-3G.

Abstract

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.