This application is to continue our studies examining the role of von Willebrand factor (VWF) in the pathophysiologyofsicklecelldisease(SCD).DuringthecurrentfundingperiodwehaveshownthatinSCDa) theplasmaconcentrationofVWFisveryhighandthemoleculeishyperadhesive;b)transplantationofmouse SCDbonemarrowintoADAMTS13?/?miceresultsinspontaneousvaso?occlusivecrisis;c)SCDpatientplasma is able to activate endothelial cells to release VWF; d) plasma ADAMTS13 is defective in cleaving multimeric VWFandVWFstrings,butnotasmallpeptidesubstratesuchasthatcurrentlyusedintheclinicalADAMTS13 activity assay; e) VWF from SCD plasma shows less ADAMTS13?mediated proteolysis and more methionine oxidation than control VWF; f) high?dose intravenous infusion of N?acetylcysteine (NAC) decreases VWF multimersize,reducesdensecellformationanderythrocytefragmentation,andincreasestheconcentrationof plasma small molecule thiols. We also have strong evidence that the self?association of VWF is a very important factor in determining its functions, that VWF self?association is enhanced in SCD, and that the processisdecreasedbyplasmahigh?densitylipoprotein(HDL)andacceleratedbythrombospondin?1(TSP?1). We plan to continue our studies of the role of the VWF?ADAMTS13 axis with the following specific aims.
SpecificAim1 :Toidentifythemolecularlesion(s)responsiblefordefectiveADAMTS13cleavageofmultimericVWFin sicklecelldisease.WehavefoundthatADAMTS13proteolysisofmultimericVWFisdefectiveinSCDandwill investigateseveralpossibilitiesforthisdefect.
SpecificAim2 :ToevaluatetheeffectsofTSP?1orApoA?Ideficiency, orApoA?Ioverexpression,onthecourseofdiseaseinsicklemice.Here,wewilltestwhethergeneticconditionsthat eitherdiminishorworsenVWFadhesiveactivityalterthecourseofSCDinmice.
SpecificAim3 :Toevaluatethe effect on the course of SCD in mice of treatment with ADAMTS13, ApoA?I, or VWF, or with both ADAMTS13 and ApoA?I.ThesestudieswillcomplementthoseofSpecificAim2toexplorewhethertreatmentsthatalterVWF adhesiveactivitywillaffecttheacuteorchronicmanifestationsofSCD. WeexpectthesestudiestoprovidefurtherbiologicalinsightsintotherolesinSCDpathophysiologyplayedby theVWF?ADAMTS13axisandoxidativestress.WealsoanticipatethatwewilldiscovernewtargetsforSCD therapy.
Oneofthecharacteristicsofsicklecelldiseaseistheattachmentofbloodcellstobloodvessel walls.Intheapplication,weproposetocontinueworktounderstandtheroleofavesselwall protein,vonWillebrandfactor,inmediatingsomeoftheimportantclinicalmanifestationsofthe disease.Weexpectthisworktoyieldnewtreatmentsforchronicandacuteaspectsofsicklecell disease.
|Chen, Junmei; Chung, Dominic W (2018) Inflammation, von Willebrand factor, and ADAMTS13. Blood 132:141-147|
|Gust, Juliane; Hay, Kevin A; Hanafi, Laïla-Aïcha et al. (2017) Endothelial Activation and Blood-Brain Barrier Disruption in Neurotoxicity after Adoptive Immunotherapy with CD19 CAR-T Cells. Cancer Discov 7:1404-1419|
|Interlandi, Gianluca; Yakovenko, Olga; Tu, An-Yue et al. (2017) Specific electrostatic interactions between charged amino acid residues regulate binding of von Willebrand factor to blood platelets. J Biol Chem 292:18608-18617|
|Grant, Marianne A; Beeler, David L; Spokes, Katherine C et al. (2017) Identification of extant vertebrate Myxine glutinosa VWF: evolutionary conservation of primary hemostasis. Blood 130:2548-2558|
|Chung, Dominic W; Chen, Junmei; Ling, Minhua et al. (2016) High-density lipoprotein modulates thrombosis by preventing von Willebrand factor self-association and subsequent platelet adhesion. Blood 127:637-45|
|Graham, Susan M; Chen, Junmei; Chung, Dominic W et al. (2016) Endothelial activation, haemostasis and thrombosis biomarkers in Ugandan children with severe malaria participating in a clinical trial. Malar J 15:56|
|Chen, Junmei; Hinckley, Jesse D; Haberichter, Sandra et al. (2015) Variable content of von Willebrand factor mutant monomer drives the phenotypic variability in a family with von Willebrand disease. Blood 126:262-9|
|Zheng, Ying; Chen, Junmei; López, José A (2015) Flow-driven assembly of VWF fibres and webs in in vitro microvessels. Nat Commun 6:7858|
|Wang, Yi; Chen, Junmei; Ling, Minhua et al. (2015) Hypochlorous acid generated by neutrophils inactivates ADAMTS13: an oxidative mechanism for regulating ADAMTS13 proteolytic activity during inflammation. J Biol Chem 290:1422-31|