Poly-N-Acetyl Glucosamine Nanofibers Regulate Endothelial Cell Movement and Angiogenesis: Dependency on Integrin Activation of Ets1

Abstract

Poly-N-acetyl glucosamine (pGlcNAc) nanofiber-derived materials effectively achieve hemostasis during surgical procedures. Treatment of cutaneous wounds with pGlcNAc in a diabetic mouse animal model causes marked increases in cell proliferation and angiogenesis. We sought to understand the effect of the pGlcNAc fibers on primary endothelial cells (EC) in culture and found that pGlcNAc induces EC motility. Cell motility induced by pGlcNAc fibers is blocked by antibodies directed against αVβ₃ and α₅β₁ integrins, both known to play important roles in the regulation of EC motility, in vitroand in vivo. pGlcNAc treatment activates mitogen-activated protein kinase and increases Ets1, vascular endothelial growth factor (VEGF) and interleukin 1 (IL-1) expression. pGlcNAc activity is not secondary to its induction of VEGF; inhibition of the VEGF receptor does not inhibit the pGlcNAc-induced expression of Ets1 nor does pGlcNAc cause the activation of VEGF receptor. Both dominant negative and RNA interference inhibition of Ets1 blocks pGlcNAc-induced EC motility. Antibody blockade of integrin results in the inhibition of pGlcNAc-induced Ets1 expression. These findings support the hypothesis that pGlcNAc fibers induce integrin activation which results in the regulation of EC motility and thus in angiogenesis via a pathway dependent on the Ets1 transcription factor and demonstrate that Ets1 is a downstream mediator of integrin activation.

Integrin-Dependent Akt1 Activation Regulates PGC-1 Expression and Fatty Acid Oxidation

“…This effect is mediated by an induction of an integrin-dependent pathway [14]. We showed here that sNAG stimulation of HUVEC results in a marked increase in respiration in the absence of increased cell numbers.…”

“…Recent findings show that the treatment of cutaneous wounds with sNAG-derived membranes results in increased kinetics of wound healing that can be attributed, in part, to a marked increase in angiogenesis [12,13]. We have shown that sNAG treatment stimulates wound integrin-dependent signaling pathways that result in increased endothelial cell motility [12,14]. Together these findings suggest that sNAGs promote wound healing and angiogenesis via the stimulation of outside-in integrin signal transduction.…”

“…Importantly, platelet activation by sNAGs is mediated by their association with integrin β3 and activation of integrin-mediated signaling [11]. sNAGs have also been shown to be efficacious in the treatment of wounds [13,] resulting in the stimulation of integrin-mediated cell motility, increased in vitro angiogenesis and wound closure [14]. The effects of nanofiber treatment can be explained, at least in part, by an integrin-dependent regulation of cellular signaling, suggesting its use as a tool to dissect the molecular mechanisms regarding cell-cell and cell-matrix interactions.…”

A randomized, investigator-blinded, controlled pilot study to evaluate the safety and efficacy of a poly-N-acetyl glucosamine–derived membrane material in patients with venous leg ulcers

“…pGlcNAc nanofiber membranes increase cell metabolism and activate in vitro migration of endothelial and fibroblast cells. 13,26,27 In diabetic mouse studies, treatment of full-thickness wounds with pGlcNAc nanofiber membranes enhanced wound healing mainly by re-epithelialization and stimulation of angiogenesis, tissue remodeling, and endothelial cell proliferation. 13 …”

Tissue Engineering of Skeletal Muscle

“…Therefore, different approaches have been tried for controlled drug release of VEGF. Beside the use as soluble factor or immobilized in fibrin hydrogels , VEGF can be bound to nanoparticles (des Rieux et al) or nanofibers (Vournakis et al 2008) as drug delivery systems (DDS) to improve angiogenesis in vivo (Zisch et al 2003). Kim et al have demonstrated the positive therapeutic effect of nanoparticle based VEGF release in ischemic muscle tissue (Kim, J. et al).…”