本文選題：冬眠　切入點(diǎn)：廢用性肌萎縮　出處：《西北大學(xué)》2016年博士論文　論文類型：學(xué)位論文

【摘要】：Atrogin-1(又稱MAFbx/FBXO32)與MuRF-1(又稱Trim63)是哺乳動(dòng)物細(xì)胞內(nèi)重要的肌萎縮因子。Atrogin-1與MuRF-1基因表達(dá)在動(dòng)物骨骼肌廢用期間受到上游FoxO轉(zhuǎn)錄因子(包括FoxO1與FoxO3a)的調(diào)控而顯著上調(diào),而MuRF-1基因表達(dá)還受到NF-κB通路的調(diào)控。此外,之前對(duì)的研究還發(fā)現(xiàn)肌肉萎縮的程度受到了肌肉類型的影響。目前冬眠動(dòng)物因?yàn)殚L(zhǎng)期冬眠不活動(dòng)而未導(dǎo)致大多數(shù)骨骼肌發(fā)生明顯肌萎縮而受到關(guān)注。但是FoxO轉(zhuǎn)錄因子與NF-κB通路是如何參與到冬眠動(dòng)物骨骼肌atrogin-1與MuRF-1基因表達(dá)的調(diào)控,與冬眠動(dòng)物的抗肌萎縮機(jī)制之間的關(guān)系還未可知,而冬眠動(dòng)物骨骼肌中FoxO轉(zhuǎn)錄因子與NF-κB通路對(duì)atrogin-1與MuRF-1的調(diào)控是否也受到了肌肉類型的影響也還不清楚。本次研究通過(guò)對(duì)比FoxO轉(zhuǎn)錄因子與NF-κB通路在達(dá)烏爾黃鼠(Spermophilus dauricus)不同類型骨骼肌(慢縮比目魚肌,混合型腓腸肌與快縮趾長(zhǎng)伸肌)中表達(dá)的變化,探討黃鼠抗廢用性肌萎縮的潛在機(jī)制。通過(guò)檢測(cè)FoxOs,總蛋白相對(duì)表達(dá)(total FoxOs)及磷酸化FoxOs (p-FoxOs)的相對(duì)蛋白表達(dá),計(jì)算兩者的比值即p-FoxOs/total FoxOs代表了FoxOs在細(xì)胞內(nèi)的磷酸化水平,該比值的大小與FoxOs促進(jìn)atrogin-1與MuRF-1基因表達(dá)的強(qiáng)度正好相反。研究結(jié)果發(fā)現(xiàn)冬眠中黃鼠通過(guò)抑制比目魚肌中FoxOs;總蛋白表達(dá)與磷酸化作用,維持了FoxOs的磷酸化水平最終抑制了atrogin-1基因表達(dá)的上調(diào)；腓腸肌內(nèi)磷酸化作用的增加抑制了FoxOs磷酸化水平的降低從而抑制了atrogin-1基因表達(dá)的上調(diào)；趾長(zhǎng)伸肌中FoxO3a磷酸化水平未發(fā)生明顯改變,而FoxO1總蛋白表達(dá)的顯著減少也并未導(dǎo)致FoxO1的磷酸化水平的降低,兩者均有利于atrogin-1基因表達(dá)上調(diào)的抑制。由此可見黃鼠在長(zhǎng)期冬眠不活動(dòng)中,不同類型的骨骼肌中存在不同的機(jī)制可以維持FoxO對(duì)atrogin-1的轉(zhuǎn)錄活性,最終抑制骨骼肌蛋白合成的增加。此外,在短暫的陣間覺(jué)醒期間,比目魚肌與腓腸肌中FoxO轉(zhuǎn)錄因子與atrogin-1基因表達(dá)的變化相一致。出眠時(shí)黃鼠通過(guò)增加腓腸肌與趾長(zhǎng)伸肌中FoxO的磷酸化水平而抑制了atrogin-1基因表達(dá)的上調(diào)。通過(guò)檢測(cè)NF-κB途徑(IKKβ/p50途徑)在黃鼠腓腸肌中基因與蛋白表達(dá),結(jié)合之前實(shí)驗(yàn)室的研究結(jié)果發(fā)現(xiàn)冬眠中時(shí)黃鼠通過(guò)維持比目魚肌中FoxO轉(zhuǎn)錄因子磷酸化水平與NF-κB通路而抑制了MuRF-1基因表達(dá)的上調(diào)；腓腸肌中NF-κB信號(hào)的活化可能促進(jìn)了MuRF-1基因表達(dá)的上調(diào),從而促進(jìn)了腓腸肌肌肉蛋白的降解；趾長(zhǎng)伸肌中NF-κB通路被活化,但并未促進(jìn)MuRF-1基因表達(dá)的增加。由此可見,在長(zhǎng)期的冬眠不活動(dòng)中,黃鼠腓腸肌與趾長(zhǎng)伸肌中FoxO轉(zhuǎn)錄因子與NF-κB通路單獨(dú)作用于MuRF-1基因表達(dá)的調(diào)控,而在比目魚肌中則是FoxO轉(zhuǎn)錄因子與NF-κB通路協(xié)同作用于MuRF-1基因表達(dá)的調(diào)控。此外,相對(duì)于比目魚肌,黃鼠冬眠期間腓腸肌與趾長(zhǎng)伸肌對(duì)atrogin-1與MuRF-1基因表達(dá)的調(diào)控機(jī)制更為復(fù)雜。Atrogin-1和MuRF-1的表達(dá)具有組織特異性,只在骨骼肌與心肌中表達(dá),而心肌在動(dòng)物冬眠隨伴隨著的低氧低代謝條件下可以維持收縮功能,這與心肌重量的維持密切相關(guān)的。本次研究發(fā)現(xiàn)整個(gè)冬眠期間黃鼠心肌中的atrogin-1和MuRF-1的基因表達(dá)維持在低水平,有利于心肌重量的維持。同骨骼肌(腓腸肌與趾長(zhǎng)伸肌)類似,冬眠期間黃鼠心肌中的NF-κB信號(hào)被活化,但不同的是心肌細(xì)胞內(nèi)p50蛋白表達(dá)的增加并未促進(jìn)MuRF-1基因表達(dá)的上調(diào),說(shuō)明冬眠動(dòng)物心肌中NF-κB途徑對(duì)MuRF-1基因表達(dá)的調(diào)控較弱。
[Abstract]:Atrogin-1 (also called MAFbx/FBXO32) and MuRF-1 (also called Trim63) is important in mammalian cells, muscle atrophy factor.Atrogin-1 and MuRF-1 gene expression in skeletal muscle of animal waste by the upstream transcription factor during FoxO (including FoxO1 and FoxO3a) control was significantly increased, while the expression of MuRF-1 gene is regulated by NF- B pathway. In addition, before the study also found that the degree of muscle atrophy of affected muscle type. The hibernating animal hibernation is not because of the long-term activities resulted in the most obvious skeletal muscle atrophy and attention. But the FoxO and NF- transcription factor kappa B pathway is how to participate in the regulation of Atrogin-1 and MuRF-1 gene expression in skeletal muscle of hibernating animal the relationship between the hibernating animal dystrophin mechanism is not known, but the hibernating animal skeletal muscle FoxO and NF- transcription factor kappa B pathway on Atrogin-1 and MuRF-1 The regulation is also affected by the type of muscle is still unclear. This study through the comparison of FoxO and NF- transcription factor kappa B pathway in the ground squirrel (Spermophilus dauricus) of different types of skeletal muscle (slow twitch soleus, gastrocnemius and mixed fast twitch extensor digitorum longus) in the form of change, the potential mechanism to investigate the squirrel anti muscle atrophy. Through the detection of FoxOs, total protein expression (total FoxOs) and phosphorylated FoxOs (p-FoxOs) expression of relative protein, calculating the ratio between the p-FoxOs/total FoxOs on behalf of FoxOs in intracellular phosphorylation, and the ratio of the size of FoxOs promotes the expression of Atrogin-1 and MuRF-1 gene the strength of the opposite. The results found that hibernation by inhibiting FoxOs squirrel soleus muscle; total protein expression and phosphoric acid, to maintain the level of FoxOs phosphorylation can inhibit Atrogin-1 gene expression The effect of increase; reduce in the gastrocnemius muscle of phosphate can inhibit the phosphorylation of FoxOs can inhibit the expression of Atrogin-1 gene up-regulated; EDL FoxO3a phosphorylation levels did not change significantly, while the expression of FoxO1 protein was significantly reduced also did not lead to the phosphorylation level of FoxO1 decreased, both for Atrogin-1 gene expression is suppressed. Thus in the long hibernation is in ground squirrel, different mechanisms exist for different types of skeletal muscle can maintain the transcription activity of FoxO to Atrogin-1, increase the final inhibition of protein synthesis in skeletal muscle. In addition, during the awakening in the short array, consistent expression of FoxO transcription factor Atrogin-1 gene soleus and gastrocnemius muscle. The sleep ground squirrel by increasing the FoxO of gastrocnemius muscle and extensor digitorum longus in phosphorylation and inhibition of Atrogin-1 gene expression The raised. By detection of NF- kappa B pathway (IKK beta /p50 pathway) in ground squirrels in gastrocnemius muscle of gene and protein expression, combined with the research results found in laboratory before hibernation when Citellus by maintaining the soleus muscle transcription factor FoxO phosphorylation and NF- B pathway and inhibition of MuRF-1 gene expression; NF- K B signal in gastrocnemius muscle activation may contribute to the regulation of MuRF-1 gene expression, so as to promote the degradation of gastrocnemius muscle protein; extensor digitorum longus NF- kappa B pathway is activated, but did not increase the expression of MuRF-1 gene. Thus, in the long hibernation is activity, regulation of Citellus gastrocnemius muscle and extensor digitorum longus FoxO and NF- transcription factor kappa B pathway alone on the expression of MuRF-1 gene in soleus muscle is the regulation of the FoxO transcription factor kappa B pathway and NF- synergistic effects on MuRF-1 gene expression. In addition, compared with the halibut Fish muscle, tissue specific regulation mechanism of ground squirrel during hibernation of gastrocnemius muscle and extensor digitorum longus on the expression of Atrogin-1 and MuRF-1 gene expression of.Atrogin-1 and MuRF-1 is more complex, only expressed in skeletal muscle and cardiac muscle, and myocardium in animal hibernation with hypoxia with low metabolic conditions can be maintained and the systolic function. Maintain the myocardial weight closely related. This study found that the expression of myocardial hibernation in ground squirrels Atrogin-1 and MuRF-1 gene maintained at a low level, which is conducive to the maintenance of myocardial weight. With skeletal muscle (gastrocnemius muscle and extensor digitorum longus muscle) is similar to that of NF- kappa B signal is activated in squirrel myocardial hibernation but the difference is the increased expression of P50 protein in myocardial cells did not promote the regulation of MuRF-1 gene expression, indicating weak regulation of hibernating animal myocardial NF- kappa B pathway on the expression of MuRF-1 gene.

【學(xué)位授予單位】：西北大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2016
【分類號(hào)】：Q445

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本文編號(hào)：1629529