Conjugated polymers optically regulate the fate of endothelial colony-forming cells

Abstract

The control of stem and progenitor cell fate is emerging as a compelling urgency for regenerative medicine. Here, we propose a innovative strategy to gain optical control of endothelial colony-forming cell fate, which represents the only known truly endothelial precursor showing robust in vitro proliferation and overwhelming vessel formation in vivo. We combine conjugated polymers, used as photo-actuators, with the advantages offered by optical stimulation over current electromechanical and chemical stimulation approaches. Light modulation provides unprecedented spatial and temporal resolution, permitting at the same time lower invasiveness and higher selectivity. We demonstrate that polymer-mediated optical excitation induces a robust enhancement of proliferation and lumen formation in vitro. We identify the underlying biophysical pathway as due to light-induced activation of TRPV1 channel. Altogether, our results represent an effective way to induce angiogenesis in vitro, which represents the proof of principle to improve the outcome of autologous cell-based therapy in vivo.

Endothelial Transient Receptor Potential Channels and Vascular Remodeling: Extracellular Ca2 + Entry for Angiogenesis, Arteriogenesis and Vasculogenesis

“…The contribution of thermosensitive TRPV1 and TRPV4 channels to heat-induced neovascularization requires to be evaluated. This hypothesis is corroborate by the recent evidence according to which TRPV1 may integrate local heat and ROS production to stimulate ECFC proliferation and tube formation (Lodola et al, 2019). An additional facet of endothelial TRP signaling that deserves further attention is its involvement in the abnormal vascularization that features multiple diseases, such as cancer, ischemic disorders and retinal degeneration.…”

“…An earlier investigation confirmed that TRPV1 drove UCB-ECFC proliferation by mediating anandamide uptake in a Ca 2+ -independent manner, as also reported in EA.hy926 cells (Hofmann et al, 2014). More recently, however, Lodola et al (2019) revealed that optical excitation of PB-ECFCs with visible light (520 nm) induced TRPV1-mediated membrane depolarization when the cells were plated on the photo-sensitive polymer Poly(3-hexyl-thiophene) (P3HT). Visible light stimulation was able to promote TRPV1 opening by increasing ROS levels and local temperature within the cleft between the photo-sensitive substrate and cell surface, although a contribution of local pH was not ruled out.…”

“…Likely, these observations will pave the way for future studies aiming at assess the role of endothelial TRP channels in vivo. The sensitivity of endothelial TRPV channels to a moderate to large increase in local temperature also represents a puzzling issue (Watanabe et al, 2002;Mergler et al, 2010;Lodola et al, 2019). Accordingly, heat therapy induced a robust angiogenic switch in the myocardium of both healthy (Gong et al, 2006) and hypertensive (Ihori et al, 2016), whereas it rescued the capillary network and attenuated myocardial damage in a rat model of AMI (Sobajima et al, 2011).…”

“…Visible light stimulation was able to promote TRPV1 opening by increasing ROS levels and local temperature within the cleft between the photo-sensitive substrate and cell surface, although a contribution of local pH was not ruled out. Notably, optical excitation of TRPV1 promoted PB-ECFC proliferation and tube formation by inducing the nuclear translocation of p65 NF-κB (Lodola et al, 2019). The pro-angiogenic effect of TRPV1 activation was prevented by buffering intracellular Ca 2+ levels with BAPTA, thereby suggesting that Ca 2+ influx through TRPV1 was necessary to induce angiogenesis (Lodola et al, 2019).…”

“…Notably, optical excitation of TRPV1 promoted PB-ECFC proliferation and tube formation by inducing the nuclear translocation of p65 NF-κB (Lodola et al, 2019). The pro-angiogenic effect of TRPV1 activation was prevented by buffering intracellular Ca 2+ levels with BAPTA, thereby suggesting that Ca 2+ influx through TRPV1 was necessary to induce angiogenesis (Lodola et al, 2019). It has, therefore, been suggested that optoceutical stimulation of TRPV1-mediated intracellular Ca 2+ signals could represent an alternative strategy to improve the therapeutic outcome of regenerative medicine of ischemic disorders.…”