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.

Public Health Relevance

Oneofthecharacteristicsofsicklecelldiseaseistheattachmentofbloodcellstobloodvessel walls.Intheapplication,weproposetocontinueworktounderstandtheroleofavesselwall protein,vonWillebrandfactor,inmediatingsomeoftheimportantclinicalmanifestationsofthe disease.Weexpectthisworktoyieldnewtreatmentsforchronicandacuteaspectsofsicklecell disease.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
2R01HL112633-06
Application #
9312099
Study Section
Hemostasis and Thrombosis Study Section (HT)
Program Officer
Kindzelski, Andrei L
Project Start
2012-02-15
Project End
2021-05-31
Budget Start
2017-07-21
Budget End
2018-05-31
Support Year
6
Fiscal Year
2017
Total Cost
Indirect Cost
Name
Puget Sound Blood Center
Department
Type
DUNS #
092881085
City
Seattle
State
WA
Country
United States
Zip Code
98104
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