Adiponectin and Leptin Exert Antagonizing Effects on HUVEC Tube Formation and Migration Modulating the Expression of CXCL1, VEGF, MMP-2 and MMP-9

Abstract

Adiponectin and leptin are two abundant adipokines with different properties but both described such as potent factors regulating angiogenesis. AdipoRon is a small-molecule that, binding to AdipoRs receptors, acts as an adiponectin agonist. Here, we investigated the effects of AdipoRon and leptin on viability, migration and tube formation on a human in vitro model, the human umbilical vein endothelial cells (HUVEC) focusing on the expression of the main endothelial angiogenic factors: hypoxia-inducible factor 1-alpha (HIF-1α), C-X-C motif chemokine ligand 1 (CXCL1), vascular endothelial growth factor A (VEGF-A), matrix metallopeptidase 2 (MMP-2) and matrix metallopeptidase 9 (MMP-9). Treatments with VEGF-A were used as positive control. Our data revealed that, at 24 h treatment, proliferation of HUVEC endothelial cells was not influenced by AdipoRon or leptin administration; after 48 h longer exposure time, the viability was negatively influenced by AdipoRon while leptin treatment and the combination of AdipoRon+leptin produced no effects. In addition, AdipoRon induced a significant increase in complete tubular structures together with induction of cell migration while, on the contrary, leptin did not induce tube formation and inhibited cell migration; interestingly, the co-treatment with both AdipoRon and leptin determined a significant decrease of the tubular structures and cell migration indicating that leptin antagonizes AdipoRon effects. Finally, we found that the effects induced by AdipoRon administration are accompanied by an increase in the expression of CXCL1, VEGF-A, MMP-2 and MMP-9. In conclusion, our data sustain the active role of adiponectin and leptin in linking adipose tissue with the vascular endothelium encouraging the further deepening of the role of adipokines in new vessel’s formation, to candidate them as therapeutic targets.

Adipose Tissue Development Relies on Coordinated Extracellular Matrix Remodeling, Angiogenesis, and Adipogenesis

“…Additionally, the developing adipose tissue provides feedback to the sprouting vasculature in the form of paracrine signals. These signals, including adipokines, such as Leptin and Adiponectin, regulate endothelial cellular activities such as proliferation in addition to encouraging proper proteolytic activity to support the appropriate environment for developing adipocytes [ 89 ]. Several factors of this microenvironmental regulation are illustrated.…”

“…In embryonic development and prior to the maturation of white adipocytes, preadipocytes take on a hormonal role and secrete adipokines, including adiponectin [ 88 ]. These secretions have been shown to have an imperative paracrine effect in assisting angiogenesis [ 89 ]. Leptin, another adipose hormone known to play a regulatory role in satiety, has displayed an important role in regulating fetal growth and organogenesis [ 90 ], although its angiogenic implications remain unclear.…”

“…Other studies have shown the Leptin-mediated upregulation of angiogenic factors FGF-2 and VEGF, further supporting this pro-angiogenic response [ 93 , 94 ]. However, more recently, a study reported that metreleptin, a recombinant leptin analog, does not induce endothelial sprouting in a 3D gel and it also does not affect circulating angiogenic factor levels [ 89 , 95 ]. Additional research shows that adipocyte-derived leptin induces endothelial apoptosis through Ang-2, but angiogenesis occurs through VEGF and FGF-2 (also produced by adipocytes) [ 93 , 96 , 97 ], demonstrating situationally dependent responses.…”

“…However, it has been shown that Adiponectin has antagonizing effects on endothelial angiogenic activity. Adiponectin agonist, AdipoRon, promotes endothelial migration and tube formation, while also upregulating CXCL1, VEGF-A, MMP2, and MMP9 in HUVECs [ 89 ]. This angiogenic activity is due to the combination of chemotactic signaling alongside the facilitated matrix organization [ 89 , 170 ].…”

“…Adiponectin agonist, AdipoRon, promotes endothelial migration and tube formation, while also upregulating CXCL1, VEGF-A, MMP2, and MMP9 in HUVECs [ 89 ]. This angiogenic activity is due to the combination of chemotactic signaling alongside the facilitated matrix organization [ 89 , 170 ]. In cardiac fibroblasts, adiponectin promotes cellular migration through APPL1-AMPK signaling, inducing collagen and elastin remodeling but maintaining basal collagen secretion [ 170 ].…”