運動為控制肥胖及代謝綜合症有效的方法之一。Irisin是透過肌肉中的FNDC5被蛋白質水解酶切割後產生,其含有112個胺基酸。Irisin透過增加粒線體生成以及能量的消耗來增強白色脂肪棕色化和產熱效應，進而降低體重與降低胰島素抗性。由於Irisin具有抗肥胖的效果及高度的演化保守性，從2012年被發表後，Irisin即被認為是具有發展性的代謝疾病治療策略。因此，為了對抗肥胖綜合症，基因治療可能可以作為代謝疾病患者的治療方針。有鑑於此，本研究目的為製備重組腺病毒Irisin且應用於各類型細胞/器官，進一步評估其治療潛力與機制。首先，我們利用E. coli表現並純化重組蛋白Irisin，結果顯示Irisin分子量在14 kDa。接著，我們將重組蛋白Irisin打入實驗動物(兔子)，爾後，利用protein G Sepharose 親和層析法，從血清中純化得到Irisin抗體。另外，利用氯化銫超高速離心製備與純化重組腺病毒FNDC5 (Ad-FNDC5) 及重組腺病毒Irisin (Ad-Irisin)。為了闡明FNDC5 / Irisin在不同類型細胞中是否分泌表現，我們在內皮細胞 EA.hy926、肌肉細胞 C2C12、肝臟細胞 Clone-9 和胚胎腎細胞 HEK293進行基因傳送。西方墨點法 (immunoblot analysis) 和酵素免疫分析法 (ELISA) 的結果發現：Ad-Irisin 在四種類型細胞皆能增加Irisin的分泌; 然而，Ad-FNDC5僅在C2C12與Clone-9細胞中被切割且增加Irisin 分泌。此外，Ad-Irisin基因傳送能增加內皮細胞的遷移及細胞增生能力，此項結果驗證了Irisin促進血管新生的能力。另外，實驗結果亦發現：Ad-Irisin基因傳送可增強肝臟細胞AMPK/Akt訊號路徑的活性並抑制PEPCK的表現量，此項結果闡明了Irisin 在糖質新生中可能扮演的角色。本研究建立研究Irisin的基礎工具，未來有助於應用於不同細胞/器官中，並且能應用於評估Irisin 治療人類各種疾病的潛力。

Exercise represents one of the most effective approaches for control of obesity and metabolic syndromes. Irisin is a 112-residue myokine secreted by skeletal muscle through proteolytical cleavage from its precursor fibronectin type III domain containing 5 (FNDC5). Irisin stimulates brown fat-like development from white fat and thermogenesis through increasing mitochondria genesis and energy expenditure, thereby reducing body weight and insulin resistance. Because of its anti-obesity effects and evolutionary conservation, Irisin has been proposed as a promising therapeutic agent for metabolic diseases since its discovery in 2012. To combat the obesity syndrome, gene therapy approached may be required for long-term management of patients with metabolic diseases. Thus, the present study aims to generate the recombinant adenovirus vectors for Irisin production in various types of cells/organs, thereby evaluating their therapeutic potential and mechanism. Recombinant irisin was expressed and purified from E. coli with an apparent molecular weight of 14 kDa. The anti-irisin antibody was raised by periodical injection of recombinant irisin into rabbit and purified from serum using protein G Sepharose affinity chromatography. For gene delivery, adenovirus vector encoding FNDC5 (Ad-FNDC5) and irisin (Ad-irisin) were generated and purified by cesium chloride ultracentrifugation. To investigate the profile of FNDC5/irisin expression in different types of cells, endothelial EA.hy926, muscle C2C12, hepatocytes Clone-9, and embryonic kidney HEK293 cells were employed for adenovirus gene delivery. By immunoblot analysis and enzyme-linked immunoassay (ELISA), it was found that Ad-irisin effectively transduced and conferred irisin secretion in all four types of cells whereas Ad-FNDC5 evoked moderate irisin secretion only in C2C12 and Clone-9 cells. Infection with Ad-irisin enhanced the viability and migration of endothelial cells, supporting the pro-angiogenic function of irisin. Besides, Ad-irisin-infected hepatocytes exhibited elevated activities of AMPK/Akt and inhibition of PEPCK signaling, suggesting the role of irisin in gluconeogenesis in the livers. With the development of these irisin-based tools, future studies are warranted to elucidate the cellular function of irisin in different organs, thereby exploring the therapeutic potential of irisin therapy for various human diseases.

論文審定書 i
誌謝 ii
中文摘要 iii
英文摘要 iv
1. Introduction 1
2. Specific Aims 5
3. Materials and Methods 6
4. Results 13
5. Discussion 19
6. References 41

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