A novel peptide inhibitor of Dll4‐Notch1 signalling and its pro‐angiogenic functions

Abstract

Background and Purpose: The Dll4-Notch1 signalling pathway plays an important role in sprouting angiogenesis, vascular remodelling and arterial or venous specificity.Genetic or pharmacological inhibition of Dll4-Notch1 signalling leads to excessive sprouting angiogenesis. However, transcriptional inhibitors of Dll4-Notch1 signalling have not been described.Experimental Approach: We designed a new peptide targeting Notch signalling, referred to as TAT-ANK, and assessed its effects on angiogenesis. In vitro, tube formation and fibrin gel bead assay were carried out, using human umbilical vein endothelial cells (HUVECs). In vivo, Matrigel plug angiogenesis assay, a developmental retinal model and tumour models in mice were used. The mechanisms underlying TAT-ANK activity were investigated by immunochemistry, western blotting, immunoprecipitation, RT-qPCR and luciferase reporter assays.

Single-cell RNA sequencing reveals the Müller subtypes and inner blood–retinal barrier regulatory network in early diabetic retinopathy

“…The results showed that Dll4, Bmpr2, and Nrf2 were highly expressed in endothelial cells. Inhibition of the Dll4-Notch1 pathway promotes excessive sprouts and endothelial proliferation in the retina (Zhu et al, 2022), and the high expression of Bmpr2 is also conducive to regulating excessive angiogenesis. In an experimental model of Bmpr2 knockout, vascular endothelial cell proliferation was observed (Theilmann et al, 2020).…”

The Role of DLL4-Notch-VEGFR2 Signaling Pathway in Tumor Angiogenesis

“…Dll4 is the only Notch ligand mainly expressed in endothelial cells, especially in arterial endothelial cells [5]. Different from other ligands, Dll4 is cell contact-dependent and can propagate through positive feedback mechanism through activation of Notch signal [6]. Dll4 gene is located on chromosome 15q14, which is a type I single transmembrane protein composed of 685 amino acids.…”

“…In Dll4 heterozygous mice, the haploid mortality was insufficient due to defects in sprouting angiogenesis and arteriovenous formation. So far, Dll4 is the second gene causing hypo haploid death, and the first gene is vascular endothelial growth factor (VEGF), indicating that Dll4 and VEGF play an indispensable role in angiogenesis 6 . The blocking of DLL4 inhibits tumor growth by regulating tumor angiogenesis, which is characterized by promoting pathological activation of endothelial cells and excessive tumor vascular growth without function [8].…”

“…Notch signaling pathway is initiated when the extracellular domain of Notch ligand expressed on the surface of signaling cells binds to the extracellular domain of Notch receptor expressed on adjacent cells (recipient cells) [14]. After binding to ligands, the receptor undergo conformational changes, which trigger proteolytic activation of the receptor, release the intracellular domain (NICD), translocation into the nucleus [6], and interact with transcription factor RBPJK/CSL and coactivator manipulation protein (MAML) to regulate the expression of target genes [4]. This leads to induction or down-regulation of a variety of downstream targets for Notch signaling, the best downstream targets include the basic helix-loop-helix family of transcriptional inhibitors, cleavage of hairy and enhancers (HECS-1, HECS-5 and HECS-7) and hes1-related (Hey-1, -hey 2 and Hey-L) protein families [3].…”

“…Dll4-notch signaling pathway plays an important role in angiogenesis, vascular remodeling, and arterial or venous regulation [6]. DLL4-mediated activation of Notch signaling in blood vessels leads to a process known as lateral inhibition, which is critical for regulating branch formation during angiogenesis [20].…”