VEGF-induced neoangiogenesis is mediated by NAADP and two-pore channel-2–dependent Ca ²⁺ signaling

Abstract

Significance The formation of new blood vessels (neoangiogenesis) accompanies tissue regeneration and healing, but is also crucial for tumor growth, hence understanding how capillaries are stimulated to grow in response to local cues is essential for the much sought-after aim of controlling this process. We have elucidated a Ca 2+ signaling pathway involving NAADP, TPCs, and lysosomal Ca 2+ release activated in vascular endothelial cells by VEGF, the main angiogenic growth factor, and we show that the angiogenic response can be abolished, in cultured cells and in vivo, by inhibiting components of this signaling cascade. The specificity of this pathway in terms of VEGF receptor subtype, intracellular messengers, target channels and Ca 2+ storage organelles, offers new targets for novel antiangiogenic therapeutic strategies.

Calcium signals regulated by NAADP and two-pore channels - their role in development, differentiation and cancer

“…Indeed, expression of both isoforms, but particularly of TPC2, was much more pronounced in the embryo than in the adult. Recent studies of TPC knockout mice have shown them to have abnormalities in smooth muscle contraction (Tugba Durlu-Kandilci et al, 2010), receptor trafficking and endolysosomal function , storage and utilization of cholesterol by the liver (Grimm et al, 2014), angiogenesis (Favia et al, 2014), skeletal muscle function (Cang et al, 2013, brown adipose tissue thermogenesis (Lear et al, 2014) and heart contraction in response to b-adrenergic stimulation (Capel et al, 2015). Although these abnormalities may reflect defects in the signalling pathways regulating physiological responses in the affected tissues, it is also possible that they are due to disturbances of TPC expression during development.…”

Two-pore channels (TPCs): Novel voltage-gated ion channels with pleiotropic functions

“…75 Futhermore, it has been identified NAADP as a crucial second messenger in histamine-induced Ca 2C release via H1 receptors (H1R) in endothelial cells: 33 it have been shown that selective H1R activation increases intracellular NAADP levels, and that H1R induced Ca 2C release and Von Willebrand factor secretion; 33 however, TPC1 and TPC2 simultaneous silencing block this secretion, suggesting an important role of TPCs in this process. 33 Favia et al 32 demonstrated in a recent report in human umbilical vein endothelial cells (HUVEC) cells and in TPC1/TPC2 KO mice that vascular endothelial growth factor receptor 2 (VEGFR2) activation induced NAADP-dependent Ca 2C release and, 32 in fact, both the use of Ned-19 or TPC2 silencing in vitro, and also in vivo studies in TPC2 KO mice, showed an inhibition of angiogenesis induced by VEGFR2 activation. 32 …”

“…33 Favia et al 32 demonstrated in a recent report in human umbilical vein endothelial cells (HUVEC) cells and in TPC1/TPC2 KO mice that vascular endothelial growth factor receptor 2 (VEGFR2) activation induced NAADP-dependent Ca 2C release and, 32 in fact, both the use of Ned-19 or TPC2 silencing in vitro, and also in vivo studies in TPC2 KO mice, showed an inhibition of angiogenesis induced by VEGFR2 activation. 32 …”

“…Today it is known that TPCs have a role not only in ion signaling but also in intracellular vesicle trafficking, [18][19][20] participating in a wide range of pathophysiological processes; that is why in the last years TPCs have received an increased attention from the main journals in the field, and they have been related to the regulation of many biological functions at different levels, including pancreatic b-cell function, 21,22 thermogenesis, 23 nutrient sensing, 6 endolysosomal transport and functions, 19,20 exocytosis, 24,25 cytokinesis, 26 fertilization and embryogenesis, 27 cell differentiation, [28][29][30][31] angiogenesis, 32 endothelium activation mediated by histamine, 33 smooth muscle contraction, 34 autophagy, [35][36][37][38][39][40] skin pigmentation, 41 or even to the Ebola virus infection mechanism. 42 As well, recent studies have suggested their possible implication in the pathogenesis of Alzheimer disease, 36 46 Thus, TPCs have become attractive therapeutic targets, although it is necessary to go deeper into their main functions and mechanisms of action not only to clinically relevant compounds could be designed but also to understand the pathophysiology of an increased wide range of diseases related to TPCs function/dysfunction.…”

Differential effects of two-pore channel protein 1 and 2 silencing in MDA-MB-468 breast cancer cells

“…TPC1 and TPC2 appear to have distinct gating mechanisms and have been reported to play differential roles in a variety of cell types and signaling pathways [4,5]. Despite the reported role of TPC1 in cell cycle regulation in a HEK293 overexpression model [6], and the role of TPC2, but not TPC1, in angiogenesis-associated signaling pathways [7], these channels have not been assessed in detail in breast cancer cell lines.…”