Ninjurin 1 dodecamer peptide containing the N-terminal adhesion motif (N-NAM) exerts proangiogenic effects in HUVECs and in the postischemic brain

Abstract

Nerve injury-induced protein 1 (Ninjurin 1, Ninj1) is a cell adhesion molecule responsible for cell-to-cell interactions between immune cells and endothelial cells. In our previous paper, we have shown that Ninj1 plays an important role in the infiltration of neutrophils in the postischemic brain and that the dodecamer peptide harboring the Ninj1 N-terminal adhesion motif (N-NAM, Pro26-Asn37) inhibits infiltration of neutrophils in the postischemic brain and confers robust neuroprotective and anti-inflammatory effects. In the present study, we examinedt the pro-angiogenic effect of N-NAM using human umbilical vein endothelial cells (HUVECs) and rat MCAO (middle cerebral artery occlusion) model of stroke. We found that N-NAM promotes proliferation, migration, and tube formation of HUVECs and demonstrate that the suppression of endogenous Ninj1 is responsible for the N-NAM-mediated pro-angiogenic effects. Importantly, a pull-down assay revealed a direct binding between exogenously delivered N-NAM and endogenous Ninj1 and it is N-terminal adhesion motif dependent. In addition, N-NAM activated the Ang1-Tie2 and AKT signaling pathways in HUVECs, and blocking those signaling pathways with specific inhibitors suppressed N-NAM-induced tube formation, indicating critical roles of those signaling pathways in N-NAM-induced angiogenesis. Moreover, in a rat MCAO model, intranasal administration of N-NAM beginning 4 days post-MCAO (1.5 µg daily for 3 days) augmented angiogenesis in the penumbra of the ipsilateral hemisphere of the brain and significantly enhanced total vessel lengths, vessel densities, and pro-angiogenic marker expression. These results demonstrate that the 12-amino acid Ninj1 peptide, which contains the N-terminal adhesion motif of Ninj1, confers pro-angiogenic effects and suggest that those effects might contribute to its neuroprotective effects in the postischemic brain.

miR-125a-5p attenuates macrophage-mediated vascular dysfunction by targeting Ninjurin1

“…Matsuki et al reported that Ninj1 is highly expressed in capillary pericytes (cPCs), is weakly expressed in ECs of the thoracic aorta, and could act as an anti-angiogenic regulator of cPCs in ischemic models [ 51 ]. Additionally, Yin et al showed that Ninj1 blockade enhanced penile angiogenesis in erectile dysfuntion [ 8 ] and Kim et al reported that dodecamer peptide Ninj1 promotes angiogenesis during strokes [ 9 ]. Compared to dysregulated angiogenesis in DR, these lesions differ in that vasoreparative processes are caused by ischemic injury and the main players are pericytes instead of macrophages [ 52 ].…”

“…Therefore, inflammatory stimuli induce Ninj1 expression in leukocytes, enhancing adhesion to VECs and the extracellular matrix (ECM) and recruitment to the site of inflammation [ 6 ]. Various trials have been conducted to regulate the inflammation mediated by Ninj1-neutralizing antibodies, small interfering RNA (siRNA), peptides, and natural products [ 4 , 7 – 9 ]. However, a strategy to effectively regulate Ninj1 expression has not yet been established.…”

Molecular Mechanisms Underlying Pathological and Therapeutic Roles of Pericytes in Atherosclerosis

“…Ninjurin 1 (nerve injury-induced protein 1, or Ninj1) is a cell adhesion molecule responsible for cell–to–cell interactions between different cells and involved in many molecular pathways and processes (neuroinflammation, angiogenesis, muscle and osteoclasts development and others) [ 92 , 93 ]. Ninj1 is also involved in ECs\pericytes interaction and serves as a negative regulator of neovessel formation.…”

Role of pyroptosis in atherosclerosis and its therapeutic implications

“…Further research found Ninj‐1 soluble form (soluble Ninj‐1, sNinj‐1) was increased in serum of atherosclerosis patient, and it was identified as an antiinflammatory mediator with the ability to ameliorate monocyte recruitment and development of atherosclerosis (Jeon et al, 2020). Moreover, another study demonstrated that the N‐terminal adhesion motif of Ninj‐1 exerted proangiogenic effects in HUVEC, contributing to its neuroprotective effects in the animal model of stroke (Kim et al, 2020).…”