CongenitalHeartDisease(CHD)isthemostcommonbirthdefectaffectingapproximately1%ofalllivebirthsin theUSandisoneoftheleadingcausesofinfantmortality.AsevereformofCHDcanresultfromheterotaxy,a disorder of Left-Right (LR) patterning, during embryonic development. A recent genetic analysis of heterotaxy patientsidentifiedanovelCHDcandidategene,LRPPRC.LRPPRCencodesamitochondrialmRNAstabilizer which is critical for oxidative (aerobic) metabolism in the mitochondria. However, it has no known role in LR patterningorembryonicdevelopment.Usingdifferentknockdown/knockoutstrategiesinthehigh-throughputhu- man disease model, Xenopus, loss of lrpprc leads to LR patterning defects that recapitulate the patient?s phenotype.Theoverallgoalofthisproposalistoinvestigatethemolecularmechanismbywhichlrpprc affectsLRpatterningandheartdevelopmentintheXenopus(frog)modelsystemanddeterminehowits roleinmitochondrialmetabolismrelatestotheregulationofearlyembryonicdevelopment.
The firstaim will determine the required role of lrpprc during embryonic patterning by using loss of function experiments to assesschangesinleft-rightanddorsal-ventralpatterningmarkersduringtheLRpatterningcascadeandearlier, atgastrulation.
The secondaim willinvestigatethemechanismbywhichlrpprcregulatesembryonicpatterning;? specifically, experiments will determine if the protein?s known mitochondrial function is important for its role in LRpatterningandcardiacdevelopment.Byattemptingtophenocopyleft-rightanddorsal-ventralpatterningde- fects through knockdown of other key OXPHOS regulatory proteins, performing real-time analysis of O2 consumption(oxidativemetabolism)andglycolysisduringkeydevelopmentalevents,andconfirmingthatLrpprc isrequiredinthemitochondriaduringearlydevelopment,experimentsinthisaimwillbetterdefiningtherelation- shipsbetweenlrpprc,metabolism,andearlyembryonicpatterninganddevelopment.Altogether,thisprojectwill improveourunderstandingofcardiacdevelopmentandtheroleoflrpprcandmitochondrialmetabolisminthe pathogenesisofCHD.Inthefuture,thiswillbenefitgenetictestingandcounseling,aswellasimproveoutcomes inCHDbecausetreatmentscanbetailoredtogenotyperatherthansolelyonCHDphenotype.Inaddition,this applicationdetailstheapplicant?strainingplanincludingresearchmentorship,advancedcoursework,trainingin new techniques, and the development of skills in scientific professionalism, writing, and presentation of data. The research and training outlined in this application will prepare the applicant to pursue a career performing patient-drivenresearchasanindependentresearchscientist.
Congenital Heart Disease, or birth defects of the heart, is the most common type of birth defect and is one of theleadingcausesofinfantdeath,affectingapproximately1%ofalllivebirthsintheUS.Studyingthefunction of genes that may cause birth defects of the heart will improve our understanding of how the heart develops within the womb. In the future, this knowledge will benefit genetic testing and counseling, as well as improve outcomesinpatientsbecausetreatmentscanbetailoredspecificallyforeachpatient.
