title: X-ray fluorescence microscopy reveals large-scale relocalization and extracellular translocation of cellular copper during angiogenesis.
abstract: Although copper has been reported to influence numerous proteins known to be important for angiogenesis, the enhanced sensitivity of this developmental process to copper bioavailability has remained an enigma, because copper metalloproteins are prevalent and essential throughout all cells. Recent developments in x-ray optics at third-generation synchrotron sources have provided a resource for highly sensitive visualization and quantitation of metalloproteins in biological samples. Here, we report the application of x-ray fluorescence microscopy (XFM) toin vitro models of angiogenesis and neurogenesis, revealing a surprisingly dramatic spatial relocalization specific to capillary formation of 80-90% of endogenous cellular copper stores from intracellular compartments to the tips of nascent endothelial cell filopodia and across the cell membrane. Although copper chelation had no effect on process formation, an almost complete ablation of network formation was observed. XFM of highly vascularized ductal carcinomas showed copper clustering in putative neoangiogenic areas. This use of XFM for the study of a dynamic developmental process not only sheds light on the copper requirement for endothelial tube formation but highlights the value of synchrotron-based facilities in biological research.
authors.affiliation: Biosciences Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439, USA.
authors.forename: Lydia
authors.initials: L
authors.lastname: Finney
authors.forename: Suneeta
authors.initials: S
authors.lastname: Mandava
authors.forename: Lyann
authors.initials: L
authors.lastname: Ursos
authors.forename: Wen
authors.initials: W
authors.lastname: Zhang
authors.forename: Diane
authors.initials: D
authors.lastname: Rodi
authors.forename: Stefan
authors.initials: S
authors.lastname: Vogt
authors.forename: Daniel
authors.initials: D
authors.lastname: Legnini
authors.forename: Jorg
authors.initials: J
authors.lastname: Maser
authors.forename: Francis
authors.initials: F
authors.lastname: Ikpatt
authors.forename: Olufunmilayo I
authors.initials: OI
authors.lastname: Olopade
authors.forename: David
authors.initials: D
authors.lastname: Glesne
mesh_terms: D001692:Biological Transport; D044584:Carcinoma, Ductal / Q000737:chemistry; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D003300:Copper / Q000378:metabolism* / Q000502:physiology*; D004730:Endothelium, Vascular / Q000166:cytology / Q000254:growth & development; D006801:Humans; D008856:Microscopy, Fluorescence; D009389:Neovascularization, Pathologic; D018919:Neovascularization, Physiologic; D014965:X-Rays
chemical_list: D003300:Copper