Scientific Report 2003-2004 - Cleveland Clinic Lerner Research ...

Maintenance of blood-vessel-wallfunction depends on the equilibriumbetween inflammatory or injuriousprocesses that may damage vascular cells andimpede their function and healing processes thataccelerate the recovery of the blood vessel frominjury. We are investigating specific aspects ofboth processes, since both are likely to influencethe behavior of blood vessels under normal andpathological conditions, especially duringatherogenesis.Endothelial Cell MotilityEndothelial cell (EC)movement is a critical,initiating event in theformation of new bloodvessels and the repair ofinjured vessels. Our laboratoryis interested in the regulationof EC motility by lipids andlipoproteins, specifically thefunction of the plasmamembrane in cell motility. Wehave recently shown that themicroviscosity of the plasmamembrane is a criticaldeterminant in regulating ECmovement. Using multiplephysiological agents, a simplebiphasic dependency wasobserved in which moderate increases inmembrane microviscosity stimulated ECmigration; however, increases in membranemicroviscosity beyond an optimal thresholdinhibited migration. Surprisingly, two angiogenicgrowth factors, vascular endothelial growthfactor and basic fibroblast growth factor, alsoincreased EC membrane microviscosity. We arenow investigating the biochemical mechanisms bywhich angiogenic growth factors alter membranemicroviscosity, e.g., caveolin-mediated cholesteroltranslocation. We are also investigating themechanisms by which membranes influence cellmovement; our attention is focused on interactionsof membranes with cytoskeletal proteinsand with rac and other small G-proteins thatregulate motility. In a related collaborativeproject with Dr. Linda Graham, we are studyingthe effects of oxidized lipids and lipoproteins onthe healing of synthetic vascular grafts in vivo.Structure, Function of Human CeruloplasminA second major project involves studies ofthe function of ceruloplasmin, an acute-phasereactant protein secreted by the liver and byactivated macrophages. Ceruloplasmin contains 7copper atoms and carries 95% of the serumcopper. Evidence from our laboratory indicatesthat ceruloplasmin has a potent pro-oxidantactivity, catalyzed by a single copper atom, thatThe Department of Cell BiologyEndothelial Cell Motility, CeruloplasminFunction Impact Vessel Wall Healthdramatically increases the rate of oxidation oflow-density lipoprotein. We are actively pursuingthe role of ceruloplasmin in cell-mediatedoxidative processes in vitro and in atheroscleroticlesions. A principal approach involves the use oftransgenic animal models of atherosclerosis. Weare also investigating the molecular mechanisms,at both the transcriptional and posttranscriptionallevels, that regulate ceruloplasmin synthesis.The recent discovery of “aceruloplasminemia”as a humangenetic disorder leading topathologic accumulationof iron has led us toinvestigate the specificrole of ceruloplasmin iniron homeostasis. We haveshown that ceruloplasminpromotes iron flux intocells of erythroid originand also that ceruloplasminproduction istranscriptionally regulatedby hypoxia-induciblefactor-1. These findingssuggest that ceruloplasminhas an important role inerythropoiesis, particularlyduring stress. We arePaul L. Fox, Ph.D.investigating the role ofceruloplasmin in iron metabolism in mice lackingthe ceruloplasmin gene and in a mouse model ofchronic renal failure.THE P. FOXLABORATORYPROJECT SCIENTISTBarsanjit Mazumder, Ph.D.POSTDOCTORAL FELLOWSPrabar Ghosh, Ph.D.Rupak Mukhopadhyay, Ph.D.Vasudevan Seshadri, Ph.D.Nicholas Tripoulas, Ph.D.RESEARCH TECHNOLOGISTSAlena Nikolskaya, M.S.Angela Serrani, B.S.GRADUATE STUDENTSSrujana Cherukiri, B.S.Paul Pavicic, B.S.Prabha Sampath, M.S.Joydeep Sarkar, B.A.Amit Vasanji, B.S.Ke Ya, M.S.COLLABORATORSLinda Graham, M.D. 1Alan Lichtin, M.D. 2Saul Nurko, M.D. 31Depts. of Vascular Medicineand Biomedical Engineering,CCF2Dept. of Hematology/MedicalOncology, CCF3Dept. of Nephrology/Hypertension, CCFMukhopadhyay, C.K., Attieh, Z.K., and P.L Fox (1998) Role of ceruloplasmin in cellulariron uptake. Science 279:714-717.Salvado, M.O., and P.L. Fox (2001) Palmitoylation of caveolin-1 in endothelial cells ispost-translational but irreversible. J. Biol. Chem. 276:15776-15782.Mazumder, B., Seshadri, V., Imataka, H., Sonenberg, N., and P.L. Fox. (2001)Translational silencing of ceruloplasmin requires the essential elements of mRNAcircularization: poly(A) tail, poly(A)-binding protein, and eukaryotic translation initiationfactor 4G. Mol. Cell. Biol. 21:6440-6449.Seshadri, V., Fox, P.L., and C.K. Mukhopadhyay (2002) Dual role of insulin intranscriptional regulation of the acute phase reactant ceruloplasmin. J. Biol. Chem.277:27903-27911.Ghosh, P.K., Vasanji, A., Murugesan, G., Eppell, S.J., Graham, L.M., and P.L. Fox(2002) Membrane microviscosity regulates endothelial cell motility. Nat. Cell Biol.4:894-900.Fox, P.L. (2003) The copper-iron chronicles: the story of an intimate relationship.Biometals 16:9-40.Mazumder, B., Seshadri, V., and P.L. Fox (2003) Translational control by the 3'-UTR:the ends specify the means. Trends Biochem. Sci. 28:91-98.Sampath, P., Mazumder, B., Seshadri, V., and P.L. Fox (2003) Transcript-selectivetranslational silencing by gamma interferon is directed by a novel structural element inthe ceruloplasmin mRNA 3' untranslated region. Mol. Cell. Biol. 23:1509-1519.73