Loss of Siah2 does not impact angiogenic potential of murine endothelial cells.
Angiogenesis is triggered in response to hypoxia under many circumstances, from healthy cells and tissues during embryogenesis to pathological conditions like the formation of new blood vessels to supply tumours and promote invasive cancer. Siah2 has been shown to regulate the hypoxia pathway upstream of hypoxia-induced transcription factor subunit Hif-1alpha, and therefore may play an important role in angiogenesis in response to hypoxic stress in endothelial cells. This study aims to investigate the basic function of Siah2 in endothelial cells under hypoxia and to test the ability of Siah2 deficient cells to mount an angiogenic response when deprived of oxygen. We and others have previously shown that Siah2 is crucial for mediating the hypoxic response in many different cell types studied. In this study however, we describe that Siah2(-/-) endothelial cells have an intact hypoxic signalling pathway, including Hif-1alpha stabilisation and gene expression, the first report of a tissue or cell lineage in which the loss of Siah2 does not seem to impact hypoxic response signalling. In mice, the infiltration of Siah2(-/-) endothelial cells into a Matrigel plug containing a VEGF-A attractant was similar compared with wildtype endothelial cells. Ex vivo however, there was a reduced capacity of Siah2(-/-) aorta to form tubes or new vessels. Thus, we conclude that Siah2 is not essential for the hypoxic response of endothelial cells.
Tumour Microenvironment Laboratory, QIMR Berghofer Medical Research Institute, 300 Herston Road, Herston, QLD 4006, Australia.
Christina S F
CS
Wong
Peter MacCallum Cancer Centre, St. Andrews Place, East Melbourne, VIC 3002, Australia.
Anna
A
Chen
Peter MacCallum Cancer Centre, St. Andrews Place, East Melbourne, VIC 3002, Australia.
Mira C P
MC
Liu
Department of Biochemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC 3086, Australia.
Belinda S
BS
Parker
Tumour Microenvironment Laboratory, QIMR Berghofer Medical Research Institute, 300 Herston Road, Herston, QLD 4006, Australia; School of Medicine, University of Queensland, Brisbane, QLD 4072, Australia. Electronic address: andreas.moller@qimrberghofer.edu.au.
Andreas
A
Möller
D000818:Animals; D001011:Aorta / Q000166:cytology / Q000254:growth & development / Q000378:metabolism; D015687:Cell Hypoxia / Q000235:genetics / Q000502:physiology; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000166:cytology* / Q000378:metabolism*; D015870:Gene Expression; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000235:genetics / Q000378:metabolism; D066298:In Vitro Techniques; D051379:Mice; D018345:Mice, Knockout; D055806:Microvessels / Q000166:cytology / Q000254:growth & development / Q000378:metabolism; D018919:Neovascularization, Physiologic; D011506:Proteins / Q000235:genetics; D015398:Signal Transduction; D044767:Ubiquitin-Protein Ligases / Q000172:deficiency* / Q000235:genetics
C497443:Hif1a protein, mouse; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D011506:Proteins; C484442:Siah1a protein, mouse; C484443:Siah1b protein, mouse; C533102:Siah2 protein, mouse; D044767:Ubiquitin-Protein Ligases
Angiogenesis; Endothelial; Hypoxia; Siah; Ubiquitin ligase