Of note, TRPV1 controls ECFCs angiogenic activity both in a Ca2+-dependent and self-employed manner [44,120]; in particular, Lodola et al. tubulogenesis, through the integration of several chemical stimuli. Herein, we 1st summarize TRPV1 structure and gating mechanisms. Next, we illustrate the physiological functions of TRPV1 in vascular endothelium, focusing our attention on how endothelial TRPV1 promotes angiogenesis. In particular, we describe a recent strategy to stimulate TRPV1-mediated pro-angiogenic activity in ECFCs, in the presence of a photosensitive conjugated polymer. Taken collectively, these observations suggest that TRPV1 represents a useful target in the treatment of ischemic diseases. Benth., Rutaceae) . Ching et al. investigated TRPV1-mediated eNOS activation and NO-dependent angiogenesis both in vitro and in vivo . They found that evodiamine and capsaicin induced eNOS activation by phosphorylation and consequent NO launch: Both of these effects were inhibited by pharmacological (with capsazepine) and genetic (with a specific small interfering RNA, siRNA) silencing of TRPV1. Evodiamine-induced TRPV1 activation was then found to recruit the Ca2+-dependent PI3K/Akt/CaMKII signaling pathway, which turned out to be necessary for ligand-induced phosphorylation of both TRPV1 and eNOS (Number 3) . Indeed, TRPV1 served like a scaffold for the recruitment and formation of a supermolecular complex consisting also of Akt, CaMKII and eNOS, which favored eNOS phosphorylation and NO launch (Number 4). This signaling pathway was also recognized in mouse aortic endothelial cells (MAECs), in which genetic deletion of TRPV1 still prevented evodiamine from recruiting the PI3K/Akt/CaMKII/eNOS signaling cascade . Of note, intraperitoneally injected evodiamine improved eNOS, Akt, and CaMKII phosphorylation in WT, but not 4-Demethylepipodophyllotoxin TRPV1?/? mice. NO has long been known to promote neovascularization by stimulating both angiogenesis and vasculogenesis [136,164,165,166]. Consistently, the Matrigel plug assay confirmed that evodiamine advertised angiogenesis in vivo, although neovascularization was prevented in TRPV1?/? and eNOS-deficient (eNOS?/?) mice . Of notice, atherosclerotic lesions were more pronounced in ApoE-knockout mice (ApoE?/?), a widely used animal model for hyperlipidemia, upon further deletion of TRPV1 (ApoE?/? TRPV1?/?). Similarly, evodiamine-induced phosphorylation of Akt, CaMKII, and eNOS was reduced ApoE?/?TRPV1?/?, as compared to TRPV1?/? mice . A subsequent report further showed that evodiamine and capsaicin recruited AMP-activated protein kinase (AMPK) to phosphorylate eNOS inside a CaMKII-dependent manner (Number 4) . Indeed, evodiamine also induced AMPK phosphorylation, but this effect was inhibited by obstructing TRPV1 with capsazepine and CaMKII with the selective inhibitor KN62 . Finally, evodiamine-induced eNOS phosphorylation was strongly reduced by compound C, a specific AMPK blocker, by overexpressing a dominating bad AMPK (dnAMPK) in Main Bovine Aortic Endothelial Cells (BAECs). In agreement with these observations, AMPK activity proved to be essential for the ligand-induced physical association between TRPV1 and eNOS. As expected, pharmacological (with capsazepine) and/or genetic (with dnAMPK) blockade of AMPK also inhibited PROML1 evodiamine-induced tube formation in Matrigel scaffolds both in vitro and in vivo . Of notice, this investigation shown, for the first time, that TRPV1 could be efficiently targeted to stimulate restorative angiogenesis. Intraperitoneal injection of evodiamine advertised neovascularization inside a mouse model of hindlimb ischemia in an AMPK-dependent manner. Moreover, evodiamine reduced atherosclerotic plaques and improved phosphorylation of AMPK and eNOS in ApoE?/?, but not ApoE?/?TRPV1?/? mice . These studies, therefore, strongly suggest that pharmacological activation of TRPV1 could symbolize an alternative strategy to induce restorative angiogenesis in ischemic cells, actually in the presence of founded cardiovascular risk factors, e.g., hyperlipidemia. Open in a separate window Number 3 TRPV1 route in angiogenesis. TRPV1 stimulates angiogenesis in response to 4-Demethylepipodophyllotoxin evodiamine, simvastatin, EPO, epigallo-catechin-3-gallate, and 14,15-EETS within a Ca2+-reliant way. Conversely, extracellular anandamide might enter through TRPV1, stimulating angiogenesis within a Ca2+-indie way thereby. Open in another 4-Demethylepipodophyllotoxin window Body 4 Proposed molecular system of eNOS arousal after 4-Demethylepipodophyllotoxin TRPV1 activation. Activation of TRPV1 boosts Ca2+ influx, which activates PI3K/Akt/CaMKII signaling, resulting in increased eNOS and TRPV1 phosphorylation. In addition, TRPV1 might serve as a.