Combined use of X-ray fluorescence microscopy, phase contrast imaging for high resolution quantitative iron mapping in inflamed cells

X-Ray Microscopy Conference 2016

Gramaccioni, C.^1,4 ; Procopio, A.^2 ; Farruggia, G.^2 ; Malucelli, E.^2 ; Iotti, S.^2 ; Notargiacomo, A.^3 ; Fratini, M.^4,5 ; Yang, Y.^6 ; Pacureanu, A.^6 ; Cloetens, P.^6 ; Bohic, S.^6 ; Massimi, L.^4 ; Cutone, A.^7 ; Valenti, P.^7 ; Rosa, L.^7 ; Berlutti, F.^7 ; Lagomarsino, S.^4

Department of Physics, University of Cosenza, Arcavata di Rende, (Cosenza), Italy^1

Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy^2

Institute for Photonics and Nanotechnologies, CNR, Roma, Italy^3

CNR-Nanotec, C/o Department of Physics, University of Sapienza, Roma, Italy^4

Fondazione Santa Lucia, Roma, Italy^5

ESRF, Grenoble, France^6

Department of Public Health and Infectious Diseases, University of Sapienza, Roma, Italy^7

关键词: Biology and medicine;    Element concentrations;    High spatial resolution;    Inflammatory process;    Iron-binding protein;    Phase-contrast imaging;    Quantitative mapping;    X-ray fluorescence microscopy;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/849/1/012008/pdf
DOI  :  10.1088/1742-6596/849/1/012008

来源: IOP

【 摘 要 】

X-ray fluorescence microscopy (XRFM) is a powerful technique to detect and localize elements in cells. To derive information useful for biology and medicine, it is essential not only to localize, but also to map quantitatively the element concentration. Here we applied quantitative XRFM to iron in phagocytic cells. Iron, a primary component of living cells, can become toxic when present in excess. In human fluids, free iron is maintained at 10-18M concentration thanks to iron binding proteins as lactoferrin (Lf). The iron homeostasis, involving the physiological ratio of iron between tissues/secretions and blood, is strictly regulated by ferroportin, the sole protein able to export iron from cells to blood. Inflammatory processes induced by lipopolysaccharide (LPS) or bacterial pathoge inhibit ferroportin synthesis in epithelial and phagocytic cells thus hindering iron export, increasing intracellular iron and bacterial multiplication. In this respect, Lf is emerging as an important regulator of both iron and inflammatory homeostasis. Here we studied phagocytic cells inflamed by bacterial LPS and untreated or treated with milk derived bovine Lf. Quantitative mapping of iron concentration and mass fraction at high spatial resolution is obtained combining X-ray fluorescence microscopy, atomic force microscopy and synchrotron phase contrast imaging.