Down syndrome candidate region 1-like 1 (DSCR1-L1) mimics the inhibitory effects of DSCR1 on calcineurin signaling in endothelial cells and inhibits angiogenesis.
In endothelial cells, binding of vascular endothelial growth factor (VEGF) to VEGF receptor 2 leads to the activation of the serine/threonine phosphatase calcineurin, dephosphorylation of the nuclear factor of activated T-cells (NF-AT) transcription factors, translocation of NF-AT to the nucleus, and expression of angiogenesis-related genes such as Cox-2. Down syndrome candidate region 1 (DSCR1) is transactivated by NF-AT nuclear translocation, and subsequently inhibits calcineurin activity, forming a negative feedback loop. While DSCR1 has a clearly defined role as an endogenous inhibitor of VEGF-calcineurin-mediated angiogenesis in endothelial cells, the function of the DSCR1 family member, DSCR1-like 1 (DSCR1-L1), has not yet been investigated in endothelial cells. Here we show that a panel of pro-angiogenic factors, including VEGF, basic fibroblast growth factor (bFGF), angiopoietin 1, hepatocyte growth factor, as well as triiodo-l-thyronine (T(3)), does not induce DSCR1-L1 up-regulation in endothelial cells, while VEGF potently up-regulates DSCR1. To investigate the effects of DSCR1-L1 on endothelial cell function, we cloned the gene into a lentiviral vector and overexpressed DSCR1-L1 in human umbilical vein endothelial cells. Constitutive DSCR1-L1 overexpression prevented the nuclear translocation of NF-ATc1 in response to VEGF, underscoring its role as a calcineurin inhibitor. Additionally, DSCR1-L1-transduced cells inhibited VEGF-induced endothelial cell migration, proliferation, and tube formation by 36, 77, and 39%, respectively, compared to cells infected with control virus. Overexpression of DSCR1-L1 in the transformed endothelial cell line Sven 1 ras also resulted in decreased proliferation. Our findings demonstrate that DSCR1-L1 is constitutively expressed in endothelial cells and acts similar to DSCR1 in inhibiting calcineurin activity and restraining VEGF-mediated angiogenesis.
Gollogly
Lila K
LK
Division of Surgical Oncology, Department of Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114, USA.
Ryeom
Sandra W
SW
Yoon
Sam S
SS
D042683:Angiopoietin-1 / Q000502:physiology; D019703:Calcineurin / Q000502:physiology*; D002465:Cell Movement / Q000502:physiology; D049109:Cell Proliferation; D002478:Cells, Cultured; D004268:DNA-Binding Proteins; D004730:Endothelium, Vascular / Q000166:cytology / Q000502:physiology*; D016222:Fibroblast Growth Factor 2 / Q000502:physiology; D017228:Hepatocyte Growth Factor / Q000502:physiology; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000502:physiology*; D009124:Muscle Proteins / Q000235:genetics / Q000502:physiology*; D018919:Neovascularization, Physiologic / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology*; D014284:Triiodothyronine / Q000502:physiology; D015854:Up-Regulation; D042461:Vascular Endothelial Growth Factor A / Q000502:physiology
D042683:Angiopoietin-1; D004268:DNA-Binding Proteins; D047908:Intracellular Signaling Peptides and Proteins; D009124:Muscle Proteins; C108612:RCAN1 protein, human; C100360:RCAN2 protein, human; D042461:Vascular Endothelial Growth Factor A; D014284:Triiodothyronine; D016222:Fibroblast Growth Factor 2; D017228:Hepatocyte Growth Factor; D019703:Calcineurin