胃保護(hù)素對(duì)破骨細(xì)胞的作用

關(guān)于胃保護(hù)素對(duì)破骨細(xì)胞的作用第一頁(yè)，共十七頁(yè)，編輯于2023年，星期三

Ghrelin(胃動(dòng)素、胃腸動(dòng)素)是生長(zhǎng)激素促分泌物質(zhì)受體(growthhormonesecretagoguereceptor,GHS-R)的內(nèi)源性配體.

Ghrelin的結(jié)構(gòu)：

Ghrelin是由28個(gè)氨基酸組成的小分子多肽，它有兩種形式：Ghrelin-28和des-Gln14-ghrelin,除了第14位氨基酸Gln的缺失,des-Gln14-ghrelin生物活性與Ghrelin相同。GhrelinN端第3位絲氨酸殘基上的n-辛?；╪-octanoylgroup）對(duì)生物活性具有重要作用。人和大鼠的Ghrelin在進(jìn)化上高度保守，僅11位和12位上相差兩個(gè)氨基酸。

BackgroundKnowledge第二頁(yè)，共十七頁(yè)，編輯于2023年，星期三StructuresofhumanandratghrelinsBothhumanandratghrelinsare28-aminoacidpeptides,inwhichSer3ismodifiedbyafattyacid,primarilyn-octanoicacid.Thismodificationisessentialforghrelin’sactivity.K：賴氨酸，A丙氨酸;R:精氨酸，V:纈氨酸第三頁(yè)，共十七頁(yè)，編輯于2023年，星期三Thestructureofghrelinreceptor,GHSRGHSRisaseventransmembrane-domainG-proteincoupledreceptor.TwotranscriptsareproducedfromthehumanGHSRgenebyalternativesplicing:GHSR1aencodesthefunctionalreceptor,andGHSR1b,whichistruncatedaftertransmembranedomain5,appearstobeunabletostimulateintracellularsignalingpathways.第四頁(yè)，共十七頁(yè)，編輯于2023年，星期三SignaltransductionpathwayGHsecretagogues(GHSs)stimulateGHreleasethroughtheGHSreceptor(GHS-Rorghrelinreceptor)toincreaseintracellularCa2([Ca2]i)levels.GHSsareartificialmoleculesanddonotexistinnature,sothereisnostructuralhomologybetweenghrelinandpeptideGHSs.第五頁(yè)，共十七頁(yè)，編輯于2023年，星期三SummaryGhrelinisreleasedinresponsetofasting,suchthatcirculatinglevelsarehighestimmediatelypriortomeals.Ghrelinincreasedthebone-resorbingactivityofratosteoclasts,butdidnotalterosteoclastdifferentiationinamurinebonemarrowassaynorboneresorptioninexvivocalvarialcultures.

Ghrelinshowedmitogenicactivityinosteoblasts,withastrongeffectinhumancellsandaweakereffectinratosteoblasts.第六頁(yè)，共十七頁(yè)，編輯于2023年，星期三1.IntroductionBoneturnoverisacutelyresponsivetofoodintake,withboneresorptionincreasedduringfastingandsuppressedduringfeeding.Numerousfactors,suchasnutritionalcontentorsizeofmeals,mayplayaroleinthisrelationshipandthereisevidencethatsomeguthormones,suchasglucagon-likepeptide-2[3,4],alsoaffectthenormalpostprandialreductionofboneresorption.第七頁(yè)，共十七頁(yè)，編輯于2023年，星期三Anumberofstudiesinvestigatedtheeffectsofghrelininskeletaltissue.AstudyoftheexpressionofGHSR1ainhumantissuesdemonstratedaweakpositivesignalinbonemarrow。

Osteoclastresponsetoghrelinhasneverbeeninvestigatedpreviously.Theaimofthecurrentstudywastofurtherinvestigatetheactivityofghrelininbonecells,andinparticularitspossibleroleintheacutestimulationofboneresorptionthatoccursduringfasting.

第八頁(yè)，共十七頁(yè)，編輯于2023年，星期三AcylatedghrelinBSA(牛血清白蛋白)GibcobrandFBS(胎牛血清)andmediawereusedTritiatedthymidine（氚化胸腺嘧啶）

Tartrate-resistantacidphosphatase(TRAP)stainingkit(抗酒石酸酸性磷酸酶染色試劑盒試)1,25-dihydroxyvitaminD3osteoprotegerin(OPG)（骨保護(hù)素）salmoncalcitonin（鮭魚降鈣素）Materials第九頁(yè)，共十七頁(yè)，編輯于2023年，星期三Osteoclastdifferentiationinmousebonemarrowcultures1,25V-D3(10nM)0,2,5d2,4dGhrelinC(0.1-10nM)7dTRAPstainingMNC48-wellplates

MixedmarrowcellsThemixedpopulationofcellsfromthebonemarrowisculturedinthepresenceof1,25-dihydroxyvitaminD3thatpromotesosteoclastformation第十頁(yè)，共十七頁(yè)，編輯于2023年，星期三ResultOsteoclastdifferentiationinmousebonemarrowculturesisnotaffectedbyghrelin.OPG:Recombinanthumanosteoprotegerin(10ng/mL)wasincludedasapositivecontrolforinhibitionofosteoclastogenesis.第十一頁(yè)，共十七頁(yè)，編輯于2023年，星期三Ghrelinincreasedthebone-resorbingactivityofratosteoclastsinvitroBovineboneslicesMatureosteoclastIncubatefor24hGhrelinC:1nM/10nMfixedandstainedforTRAPTRAP(+)CountScrubbingReflectedlightimageofresorptionpitsformedbyratosteoclastsonbovineboneslices

Stainanddry第十二頁(yè)，共十七頁(yè)，編輯于2023年，星期三Results

Ghrelinataconcentrationof1nMinduceda30%increaseinthenumberofpitsexcavatedbyosteoclasts,whereasat10nMtherewasonlya15%increasewhichwasnotsignificantlydifferentfromthecontrol.Thepotentinhibitorofosteoclastactivity,salmoncalcitonin(10?10M),wasusedasapositivecontrol.第十三頁(yè)，共十七頁(yè)，編輯于2023年，星期三Osteoclastactivityinmousecalvarialcultureisnotaffectedbyghrelin.Calvariaelabeledinvivowith45Cawerecollectedandincubatedexvivowithexperimentalsubstancesorvehiclefor48hours.Valuesareexpressedaspercentreleased45Cadetectedovertotal45Cainjected(3μCi).PTH:parathyroidhormone(positivecontrol).第十四頁(yè)，共十七頁(yè)，編輯于2023年，星期三Ghrelinismitogenictoprimaryhumanosteoblasts.3H-thymidineincorporationwasmeasuredasanindicatorofcellproliferation.Humanprimaryosteoblastsincubatedfor24or48hoursinthepresenceof0.1nMghrelinshoweda2-foldincreaseinproliferation,asmeasuredbythymidineincorporation.Howtodeterminethymidineincorpor