Among the most devastating causes of non-traumatic hemorrhage are the Filoviruses, including Ebola and Marburg. Fatality rates from hemorrhage by infection with either of these viruses can exceed 90%. Their outbreak potential was underscored by the 2013-2016 Ebola epidemic in West Africa, which grew from one infected toddler to over 28,000 cases and claimed ~11,000 lives. In acute filovirus infections, patients often develop endothelial leakage and disseminated intravascular coagulation. This vascular disruption, combined withseverediarrheaandvomiting,canprogresstoprofoundhypovolemia,hepaticandrenalfailure.Ebolaand Marburg viruses express a single surface glycoprotein (GP) required for host cell infection. Following macropinocytoticuptake,filovirusinfectionoccursbyGPbindingtodomainCoftheendosomalNiemann-Pick C1 (NPC1-C) receptor. The ZMapp antibody cocktail is one proposed treatment for Ebola virus, but to date therearenoapprovedsafeandeffectiveantibodyorsmallmoleculeinhibitorsforanyotherfilovirusinfection. Toaddresstheneedforimprovedtreatmentoptionsforthesepathogens,Iwillusestructure/functionanalysis tocharacterizethemechanismoftwopromisingclassesoftherapeuticcandidatesthatblockreceptorbinding andarebroadlyreactive.ThefirstclassconsistsofneutralizingantibodiesfromahumanMarburgsurvivorthat block infection by binding conserved receptor-binding sites on GP. MR191 and MR72 are both potent monoclonalantibodiesthattargetMarburg,butMR72isuniqueinitsbroadfiloviruscross-reactivity.LastyearI determined the crystal structure of MR191 in complex with Marburg virus GP and grew crystals of a MR72- MARV GP complex. Here, I propose to solve the MR72-GP complex structure, and compare antibody-GP contactstodeterminecriticalinteractionsitesandhowMR72achievescross-reactivity.SinceMR191showed lifesavingpotentialinnonhumanprimatesandisapossibletherapeuticforhumans,IwillalsoevaluateMR191 escapemutants,whichcouldbeusedtoassessitspotentialagainstemergentviralstrains.Thesecondclass includessmallmoleculecompoundstargetingtheNPC1receptor.Iwilldeterminestructuresoftwocandidate small molecule inhibitors in complex with NPC1-C, and use Ebola GP and other filovirus GPs pseudotyped ontoVesicularStomatitisVirustoassesswhetherthesecompoundsinhibitviralentry.Inthisfocusedresearch plan,IwillthususecrystalsandreagentsalreadyinhandtoapproachtreatmentofEbolaandMarburgvirus diseasefromtwoangles:immunotherapyagainstthereceptor-bindingsiteandsmallmoleculetherapyagainst the receptor. This work will be critical for understanding the inhibitory mechanisms of these therapeutic molecules, and will help guide development of safe and effective therapeutics for future outbreaks. This proposalwillcomplementmyclinicaltraininginglobalinfectiousdiseaseinSanDiegoandUganda.

Public Health Relevance

FilovirusinducedhemorrhagicfeverslikeEbolaandMarburgvirusdiseasearehighlylethalhemorrhagicfevers foundinCentralandWestAfricawithnocurrentlyapprovedtherapies.Iproposeaninvestigationoftwodifferent approachestotreatmentoffilovirusinduceddisease?antibodybasedtherapiesandsmallmoleculeinhibitors. I plan to solve high resolution structures and characterize the binding and neutralization capabilities of these therapies, thereby guiding the improvement of prospective treatments and assisting the development of new candidates.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Individual Predoctoral NRSA for M.D./Ph.D. Fellowships (ADAMHA) (F30)
Project #
7F30AI136410-02
Application #
9923803
Study Section
Special Emphasis Panel (ZRG1)
Program Officer
Davis, Mindy I
Project Start
2018-07-30
Project End
2022-07-29
Budget Start
2019-05-01
Budget End
2019-07-29
Support Year
2
Fiscal Year
2018
Total Cost
Indirect Cost
Name
La Jolla Institute
Department
Type
DUNS #
603880287
City
La Jolla
State
CA
Country
United States
Zip Code
92037