本文選題：血管內(nèi)皮抑制素 + 飲食性肥胖��； 參考：《清華大學(xué)》2015年博士論文

【摘要】：血管內(nèi)皮抑制素是一個被廣為熟知的內(nèi)源性血管新生抑制因子。盡管現(xiàn)在普遍認為脂肪組織中的血管新生是治療肥胖的一個潛在靶點,但是血管內(nèi)皮抑制素是否調(diào)控脂肪細胞分化和飲食性肥胖并不清楚。在本論文工作中,我們發(fā)現(xiàn)血管內(nèi)皮抑制素能夠抑制飲食性肥胖及其相關(guān)的代謝失調(diào)綜合征,包括胰島素抵抗、葡萄糖耐受和肝脂肪化。我們進一步的實驗結(jié)果顯示,血管內(nèi)皮抑制素能夠抑制高脂飲食肥胖小鼠脂肪組織中的血管密度。同時,它能夠抑制高脂飲食小鼠脂肪組織中促血管生成因子(包括VEGF、FGF-2和PlGF)的表達。另外,體外Traswell吊籃遷移實驗、劃線愈合遷移實驗、管腔形成實驗和體內(nèi)基質(zhì)膠栓塞實驗均證實血管內(nèi)皮抑制素能夠抑制脂肪細胞分泌物引起的內(nèi)皮細胞血管新生活性。以上實驗說明,血管內(nèi)皮抑制素能夠通過其抑制血管新生的功能抑制肥胖。本論文發(fā)現(xiàn)血管內(nèi)皮抑制素能夠抑制高脂飲食小鼠脂肪組織中脂肪細胞分化中心調(diào)控轉(zhuǎn)錄因子(PPARγ、C/EBPα和β)的表達。更加有趣的是,它能夠直接體外抑制脂肪細胞分化。我們進一步發(fā)現(xiàn),血管內(nèi)皮抑制素的功能性受體—核仁素能夠在處于分化狀態(tài)的脂肪前體細胞的膜表面高表達,這使得它能夠被脂肪前體細胞內(nèi)吞。應(yīng)用免疫共沉淀和免疫熒光實驗,我們發(fā)現(xiàn)血管內(nèi)皮抑制素能夠與Sam68相互作用,并在脂肪前體細胞核中共定位。而且,血管內(nèi)皮抑制素能夠結(jié)合Sam68的NK結(jié)構(gòu)域。文獻報道,該結(jié)構(gòu)域具有調(diào)控Sam68與RNA結(jié)合的特異性的重要功能。我們進一步揭示了血管內(nèi)皮抑制素與Sam68的相互作用能夠競爭性地抑制Sam68與mTOR前體RNA結(jié)合,從而導(dǎo)致mTOR的異常轉(zhuǎn)錄,野生型mTOR的表達水平降低。接下來的免疫印跡檢測發(fā)現(xiàn),血管內(nèi)皮抑制素能夠體內(nèi)體外抑制mTOR/S6K信號通路的活性降低。綜合以上結(jié)果,血管內(nèi)皮抑制素是通過與Sam68相互作用抑制了mTOR的表達,進而抑制mTOR/S6K信號通路的活性,最終起到抑制脂肪細胞分化的作用�？傊�,血管內(nèi)皮抑制素通過抑制脂肪細胞分化和血管新生兩大生理過程,抑制了飲食性肥胖及其相關(guān)代謝失調(diào)綜合征。其抑制脂肪細胞分化和抑制肥胖的新功能使我們對于血管內(nèi)皮抑制素的生物學(xué)功能有了新的認識,也使得血管內(nèi)皮抑制素具有了治療和預(yù)防肥胖及其相關(guān)代謝失調(diào)綜合征的潛在臨床應(yīng)用價值。
[Abstract]:Endotheliostatin is a well-known endogenous angiogenic inhibitor. Although angiogenesis in adipose tissue is now widely regarded as a potential target for the treatment of obesity, it is not clear whether vascular endothelin regulates adipocyte differentiation and dietary obesity. In this work, we found that vascular endothelin inhibits dietary obesity and its associated metabolic disorders, including insulin resistance, glucose tolerance, and liver fat. Our further results suggest that endothelin inhibits vascular density in adipose tissue of obese mice on a high fat diet. At the same time, it inhibited the expression of angiogenic factors (including VEGF FGF-2 and PlGF- 2) in adipose tissue of high fat diet mice. In addition, in vitro Traswell basket migration test, line healing migration test, lumen formation test and in vivo matrix glue embolization test all proved that vascular endothelin inhibits endothelial cell angiogenesis induced by adipocyte secretion. These results suggest that endothelin can inhibit obesity by inhibiting angiogenesis. In this study, we found that vascular endothelial inhibin could inhibit the expression of PPAR 緯 -C / EBP 偽 and 尾 in adipose tissue of high-fat diet mice. More interestingly, it can inhibit adipocyte differentiation directly in vitro. We further found that the functional receptor of vascular endothelin, nucleolipin, was highly expressed on the membrane of adipose progenitor cells in the differentiation state, which enabled it to be ingested by fat precursor cells. By means of immunoprecipitation and immunofluorescence assay, we found that vascular endothelin can interact with Sam68 and co-locate in the nucleus of fat precursor. Furthermore, endothelin can bind to the NK domain of Sam68. It is reported that this domain has the important function of regulating the specificity of Sam68 binding to RNA. We further revealed that the interaction between vascular endothelin and Sam68 could competitively inhibit the binding of Sam68 to mTOR precursor RNA, resulting in abnormal transcription of mTOR and decreased expression of wild-type mTOR. Subsequently, Western blotting showed that endothelin could inhibit the activity of mTOR-S6K signaling pathway in vivo and in vitro. Combined with the above results, endothelin inhibits the expression of mTOR by interacting with Sam68, which inhibits the activity of mTOR / S6K signaling pathway, and finally inhibits adipocyte differentiation. In conclusion, endothelin inhibits dietetic obesity and related metabolic disorders by inhibiting adipocyte differentiation and angiogenesis. Its new function of inhibiting adipocyte differentiation and obesity has given us a new understanding of the biological function of vascular endothelin. Vascular endothelin has potential clinical value in treating and preventing obesity and related metabolic disorders syndrome.
【學(xué)位授予單位】：清華大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2015
【分類號】：R589.2
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本文編號：2002763