Chemical Turns Stem Cells Into Beating Heart Cells

bobo

日期: 2004-02-20 今日/总浏览: 1/4675 h1 X3 Y0 M6 y
, I: ]. ]0 H8 u  l4 w+ x! W
" Y% I6 ]8 X' T5 w( g. }2 e
+ Y9 M" d3 s1 B
1 e* Z- q. a/ o+ S" e* ]
Scientistshavefoundawaytoturnmouseembryonicstemcellsintobeatingheartmusclecells-aresultthatcouldleadtotheuseofembryonicstemcellsincardiactherapy,andpossiblyevendrugsthatcanpromptthebodytoregenerateheartcellsonitsown.7 Q9 ?" t# z) j. r) P% O8 |6 @
Theresearch,whichappearsintheFeb.18printeditionoftheJournaloftheAmericanChemicalSociety,apeer-reviewedjournaloftheworld’slargestscientificsociety,tacklesanumberoftheobstaclesthwartingpracticalapplicationsofembryonicstemcells,whilealsopointingtoaviablepatharoundtheethicalandpoliticalconcernsencompassingthedebate., E' ^: b; [, Q$ m2 q+ G
Becauseembryonicstemcellscanturnintoanytypeofcellinthebody,manyscientistsbelievetheyholdincrediblepromisefortreatingavarietyofdegenerativediseases.Quiteafewscientifichurdles,however,standinthewayoftangibletherapiesforsuchmaladiesasdiabetes,Alzheimer’s,Parkinson’sandheartdisease.) D5 {; z+ R0 A0 f7 G7 D; d7 L
Wehavediscoveredasyntheticchemical,namedcardiogenol,whichcanselectivelydifferentiateembryonicstemcellsintobeatingcardiacmusclecells,saysXuWu,agraduatestudentinthelabofPeterG.Schultz,Ph.D,professorofchemistryatTheScrippsResearchInstituteinLaJolla,Calif.Embryonicstemcellsrepresentapotentiallyunlimitedsourceofcardiomyocytes-cellsthatcanrepairdamagedhearttissueinthebody-butuntilnowscientistshavebeenunabletocontrolthedirectionofembryonicstemcellstousetheminthetreatmentofheartdisease.
; G- ^# f5 x9 C. t3 ?SchultzandhiscoworkersatScripps,includingWuandassistantprofessorShengDing,Ph.D.,screenedavastlibraryofcompoundsinsearchofmoleculeswiththepotentialtocausestemcellstogrowintoheartmusclecells.Theyfoundfoursuchmolecules,whichtheynamedcardiogenolA-D.* d: f* l# @! Y6 }" f. P3 b
Theytestedthecardiogenolcompoundsbyusingembryonicstemcellsfrommice.Aftersevendaysgrowinginatissueculturedish,themajorityofthestemcellswereconvertedintobeatingcardiacmusclecells.
0 w! d* e* W+ N  \9 {Whilethetestsweredoneonlywithmousecells,thefundamentalbiologyshouldtransferwelltohigherorganisms.Byusingthesemoleculestounderstandtheunderlyingbiology,itshouldbepossibletoextendthisdiscoverytohumans,Wusays.2 }8 c  ^% p$ E* b1 {* O  C
InadifferentpaperpublishedrecentlyintheJournaloftheAmericanChemicalSociety,Dingandhiscolleaguesreportedthediscoveryofanothersmallmolecule-calledreversine-thatappearstoconvertadultcellsnormallyprogrammedtocreateskeletalmusclesbackintoprecursorcellswithsimilarpropertiesasstemcells.
7 ]( b! L* Z: Q8 q4 WThistypeofresearchmayultimatelyfacilitatedevelopmentofdrugsthatcanstimulatetissuestoregeneratethemselves,withoutanyneedtoharvestexternalstemcells,Dingsays.Wethinkthisrepresentsanexcitingmedicalopportunity.6 d  [" x/ q0 w1 L1 s
Muchmoreworkisrequiredtounderstandthebiologicalpropertiesandmechanismsofreversine,butthesepreliminaryresultsraisethetantalizingpossibilitythatitmaybepossibletosynthesizeacompoundthatcreatesviablestemcellsfromadulttissue,Dingsays.Suchcellswouldnotberejectedbytheimmunesystem,sincetheycomedirectlyfromthepatientwhoneedsthem.
+ ^9 v8 |  _2 R$ q+ \Amoleculelikereversinecouldbecombinedwithacardiogenol-typemoleculetoproduceadrugthatkindlesregenerationofhearttissue.Almosteverytissuehasitsownreserveofstemcells,soultimatelywehopewedon’thavetoisolatethosecellsfromthebody,Dingsays.Wecanstimulatetissuetoregeneratebyjuststimulatingcellswithinthebody.
; L: g  D! X, C8 s" n6 D1 F, AThistypeofregenerationalreadyoccursinanumberofnaturalprocesses.Inlowerorganisms,forexample,urodeleamphibianscanregeneratelostlimbsandtails.Inhumansandothermammals,thelivercanregeneratenaturally,Dingsays.Andyoungchildrencanevenregeneratefingertips.
& ~3 ]& A: x" j, o, T* f0 m: ?" bAlloftheseprocessesaredirectedbymolecularsignaling.Ifpeoplecandevelopsmallmoleculetherapeuticstopreciselymimicandcontrolthosesignalsforcorrectingdefectsorrepairingdamagedtissues,youcouldeventuallybuythoseinapharmacyasaprescriptiondrug,Dingsays.9 ~1 b# d9 M( |) u/ }
Notonlywouldthisalleviatesomeoftheethicalconcernssurroundingstemcells,butalsoaless-frequentlydiscusseddownsidetostemcelltreatments:theirinvasiveness.Small-moleculetherapiesinvolvingregenerativemedicineareprobablyyearsawayfromclinicaluse.Atpresent,Schultz,Wuandothercoworkersarefocusingonunderstandingcardiogenol’smechanismofaction,anddesigningfutureexperimentstotestthesemoleculesindiseasemodels.% A( e! D4 d; ^- w$ o4 w1 V) I

8 h/ t8 H4 t, ]- `* S* b: Q  f7 o& ~2 b9 g9 ~

: d- v% i8 D0 R% }. n
- p) z- ~$ l# e: L, F7 r0 A  b
0 b; T9 Y! o( `% w* ^5 b作者: + ~* C( m* r9 s, V) u
来源: American Chemical Society( Y5 g0 X$ F* z& T7 i9 n) v
发布者: 刘斌