Chemical Turns Stem Cells Into Beating Heart Cells

bobo

日期: 2004-02-20 今日/总浏览: 1/467
, y$ {( T9 ]) P6 B2 R
! z6 o! Q9 B! L1 T3 t: S
$ T1 ~6 Q3 \- U! P8 S" X2 o( i. }3 Z# i2 Q6 P& x
- A! @* {9 C0 }% ?9 e! W
Scientistshavefoundawaytoturnmouseembryonicstemcellsintobeatingheartmusclecells-aresultthatcouldleadtotheuseofembryonicstemcellsincardiactherapy,andpossiblyevendrugsthatcanpromptthebodytoregenerateheartcellsonitsown.
( j2 H( e2 d; b: Z$ LTheresearch,whichappearsintheFeb.18printeditionoftheJournaloftheAmericanChemicalSociety,apeer-reviewedjournaloftheworld’slargestscientificsociety,tacklesanumberoftheobstaclesthwartingpracticalapplicationsofembryonicstemcells,whilealsopointingtoaviablepatharoundtheethicalandpoliticalconcernsencompassingthedebate., T/ ]' w) b- N; O7 O( P
Becauseembryonicstemcellscanturnintoanytypeofcellinthebody,manyscientistsbelievetheyholdincrediblepromisefortreatingavarietyofdegenerativediseases.Quiteafewscientifichurdles,however,standinthewayoftangibletherapiesforsuchmaladiesasdiabetes,Alzheimer’s,Parkinson’sandheartdisease.
$ h, e: ]: d. k# L5 R8 |( NWehavediscoveredasyntheticchemical,namedcardiogenol,whichcanselectivelydifferentiateembryonicstemcellsintobeatingcardiacmusclecells,saysXuWu,agraduatestudentinthelabofPeterG.Schultz,Ph.D,professorofchemistryatTheScrippsResearchInstituteinLaJolla,Calif.Embryonicstemcellsrepresentapotentiallyunlimitedsourceofcardiomyocytes-cellsthatcanrepairdamagedhearttissueinthebody-butuntilnowscientistshavebeenunabletocontrolthedirectionofembryonicstemcellstousetheminthetreatmentofheartdisease.: a- V/ n8 L, i8 h! m; D
SchultzandhiscoworkersatScripps,includingWuandassistantprofessorShengDing,Ph.D.,screenedavastlibraryofcompoundsinsearchofmoleculeswiththepotentialtocausestemcellstogrowintoheartmusclecells.Theyfoundfoursuchmolecules,whichtheynamedcardiogenolA-D.
' D) p" P3 K1 N! {6 kTheytestedthecardiogenolcompoundsbyusingembryonicstemcellsfrommice.Aftersevendaysgrowinginatissueculturedish,themajorityofthestemcellswereconvertedintobeatingcardiacmusclecells.
6 p+ c& b/ W' v& \& ^Whilethetestsweredoneonlywithmousecells,thefundamentalbiologyshouldtransferwelltohigherorganisms.Byusingthesemoleculestounderstandtheunderlyingbiology,itshouldbepossibletoextendthisdiscoverytohumans,Wusays.
, t, n2 l6 i' A0 K5 P& u1 Y& EInadifferentpaperpublishedrecentlyintheJournaloftheAmericanChemicalSociety,Dingandhiscolleaguesreportedthediscoveryofanothersmallmolecule-calledreversine-thatappearstoconvertadultcellsnormallyprogrammedtocreateskeletalmusclesbackintoprecursorcellswithsimilarpropertiesasstemcells.
+ p3 m# L4 D+ M; lThistypeofresearchmayultimatelyfacilitatedevelopmentofdrugsthatcanstimulatetissuestoregeneratethemselves,withoutanyneedtoharvestexternalstemcells,Dingsays.Wethinkthisrepresentsanexcitingmedicalopportunity.) @( l- g( W1 z! ?6 }* P& k# s$ Y
Muchmoreworkisrequiredtounderstandthebiologicalpropertiesandmechanismsofreversine,butthesepreliminaryresultsraisethetantalizingpossibilitythatitmaybepossibletosynthesizeacompoundthatcreatesviablestemcellsfromadulttissue,Dingsays.Suchcellswouldnotberejectedbytheimmunesystem,sincetheycomedirectlyfromthepatientwhoneedsthem.
- t$ N8 T, F" A: PAmoleculelikereversinecouldbecombinedwithacardiogenol-typemoleculetoproduceadrugthatkindlesregenerationofhearttissue.Almosteverytissuehasitsownreserveofstemcells,soultimatelywehopewedon’thavetoisolatethosecellsfromthebody,Dingsays.Wecanstimulatetissuetoregeneratebyjuststimulatingcellswithinthebody./ }0 Q  o, \; s. k% h1 z
Thistypeofregenerationalreadyoccursinanumberofnaturalprocesses.Inlowerorganisms,forexample,urodeleamphibianscanregeneratelostlimbsandtails.Inhumansandothermammals,thelivercanregeneratenaturally,Dingsays.Andyoungchildrencanevenregeneratefingertips.1 d! t) D) Y$ q
Alloftheseprocessesaredirectedbymolecularsignaling.Ifpeoplecandevelopsmallmoleculetherapeuticstopreciselymimicandcontrolthosesignalsforcorrectingdefectsorrepairingdamagedtissues,youcouldeventuallybuythoseinapharmacyasaprescriptiondrug,Dingsays.
" A- v% {6 C1 ^" B6 K7 f, INotonlywouldthisalleviatesomeoftheethicalconcernssurroundingstemcells,butalsoaless-frequentlydiscusseddownsidetostemcelltreatments:theirinvasiveness.Small-moleculetherapiesinvolvingregenerativemedicineareprobablyyearsawayfromclinicaluse.Atpresent,Schultz,Wuandothercoworkersarefocusingonunderstandingcardiogenol’smechanismofaction,anddesigningfutureexperimentstotestthesemoleculesindiseasemodels.1 ~9 T& K% z9 f/ j/ ~
  F5 d; A4 l9 J! p, w  w9 t5 w
$ Q$ x/ \7 ]+ ^5 u/ {; T

/ {0 ^6 j9 s6 S. b. |  z) N5 q) l  K  \9 w/ d) ^1 r
7 C; }- R! i' R7 v* h) g* O
作者:
# Y8 Q) m3 T: O' U0 U/ c9 W5 G来源: American Chemical Society- M4 N. C3 o" H! [
发布者: 刘斌