Bone Marrow Cells Take On New Role In The Brain

韩雪娜

日期: 2003-02-05 今日/总浏览: 1/499% ?( M3 z+ [9 n8 c9 A
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* |8 F" X: L- G0 B7 F* nResearchersintheBaxterLaboratoryatStanfordUniversityMedicalCenterhavepublishednewevidenceshowingthatcellsfromthebonemarrowmighthelprepairormaintaincellsinothertissues.Inapaperinthisweek'sonlineeditionoftheProceedingsoftheNationalAcademyofSciences,theresearchersdescribefindingchromosomesfromabonemarrowtransplantinthebraincellsoftransplantrecipients.3 \7 k" M8 M* @1 o

. F, T& E( M) ]Whenpeoplereceiveabonemarrowtransplantafterhigh-dosechemotherapy,someofthetransplantedcellsregeneratetheblood-makingcellsthatweredestroyed.Inpastexperimentsinmice,HelenBlau,PhD,theDonaldE.andDeliaB.BaxterProfessorofPharmacologyattheSchoolofMedicine,foundthatcellsfromthetransplantcouldalsorelocatetotissuesthroughoutthebodyratherthanbeingrestrictedtothebonemarrowandblood.
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Nowweknowthatitcanalsohappeninhumans,saidJamesWeimann,PhD,firstauthoronthepaperandaseniorresearchscientistinBlau'slab.
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BlauandWeimannlookedatbrainsamplestakenfromwomenwhounderwentchemotherapytotreattheirleukemiaandthenlaterreceivedbonemarrowtransplantsfrommaledonors.ThesesampleswereidealforthisexperimentbecausethedonorcellscontainedaYsexchromosomewhereascellsinthewomencontainedonlyXchromosomes.AnyYchromosomethatBlauandWeimannidentifiedmusthavecomefromthetransplantdonor.
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; O( A, c* `' M" b# W4 K& gTolookforthetelltaleYchromosome,theresearchersusedmoleculeswithadoubleidentity.OnepartofthemoleculecouldbindtoeithertheXorYchromosome,whiletheotherpartactedasafluorescentmolecularbeacon.ThemoleculethatboundtheXchromosomehadaredbeaconwhereastheY-recognizingmoleculehadagreenbeacon.Whentheyputthesestainsonthepreservedsamples,theXchromosomesglowedredandanyYchromosomesglowedgreen.Weimannthensearchedthesamplesunderamicroscopeforgreenchromosomesinthebraintissue.4 W+ x( Z7 r6 I! N& F

4 [2 }5 U6 R9 P* zAsexpected,bloodcellswithinthebraincontainedYchromosomesbecausetheyweremadebybonemarrowcellsfromthetransplant.TheresearchersalsofoundfivenervecellscalledPurkinjecells-involvedincontrollingbalanceandmovement-thatcontainedYchromosomesinadditiontotheiroriginalXchromosomes.Theseout-of-placechromosomescouldonlyhavecomefrommalecellsinthebonemarrowtransplant./ C2 O" q( \7 U
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BlaususpectsthePurkinjecellsmayhavegottentheirYchromosomefromagroupoftravelingbonemarrowcells.Ithinkthesecellsmayactasarepairsquad,Blausaid.Thecellstravelthebloodstream,respondtostressandrepairdamagedtissuessuchasbrain,muscleandpossiblyothersthroughoutthebody.Sheaddedthatinsomecasesthebonemarrowcellsmightfusewithdamagedcellswhileinotherinstancestheytransformtoreplacethecells.% s% f, Y7 G) x4 [! e% B

: k: z+ N7 W* A# M- t- _Shesaidthenextstepsaretolearnwhichcellsinthebonemarrowactastherepairsquad,howthesecellsareluredtotissuesandhowtheyrepairdamageoncetheygetthere.Ifwecanlearnwhatthesignalsare,wemaybeabletodirecttherepaircellstowheretheyareneeded,Blausaid.Wouldn'titbeterrificifwecouldenlistthebodytotreatitsowndisease?1 W3 G* k# [* L8 K
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Blauaddedthatadultbonemarrowcellsmaybeparticularlyusefulfortreatingsomediseasesorsometissuesbutnotothers.Weneedtostudyalltypesofstemcells,shesaid.. [# r7 e8 X9 N/ f- v0 C: `

; d2 ^& n2 D. ]. y/ M( rOtherStanfordresearcherswhocontributedtothisworkincludeCarolCharlton,PhD,aresearchassociate,andgraduatestudentTimothyBrazelton,PhD.
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4 G, Y6 q& r0 m& x# x+ \& T来源: Stanford University Medical Center
5 X  ~7 L& @) g0 O/ V; J; m: R发布者: 刘斌