2018-08-012024-05-18https://scholars.lib.ntu.edu.tw/handle/123456789/702915摘要：成體幹細胞對於組織恆定維持與修補極為重要，幹細胞失調不僅影響組織恆定與再生，也可以導致疾病。乾癬為一後天表皮增生與脫屑的皮膚發炎疾患，約全球2~3%的人口罹患此病，且嚴重影響其生活品質。一般認為表皮的恆定常由位於皮膚基底層的幹細胞負責，表皮是由許多的表皮複製單位(epidermal proliferative unit，EPU)所構成，每個表皮複製單位由細胞分裂速度很慢的幹細胞產生快速分裂的短暫分裂細胞(transit amplifying cells)來補足日復一日因分化、脫落而失去的表皮細胞。然而表皮幹細胞處於發炎的乾癬環境中是如何反應及失調的，目前仍未清楚了解。對此，一般相信的假說是在乾癬的皮膚，表皮複製單位的表皮幹細胞會產生較一般皮膚更多的短暫分裂細胞進而導致表皮增生。然而，這樣的假說時至今日仍未得到驗證。但另一方面，近年來藉由細胞譜系追蹤(cell lineage tracing)與活體影像的技術，研究學者提出表皮可能只存在一種前趨細胞(progenitors)而沒有快速增長細胞; 但此種技術也未曾被應用於來研究乾癬表皮幹細胞的動態。在此計劃中，我們將會利用多光子顯微鏡活體影像系統(multiphoton microscopy)在帶有螢光可追蹤的乾癬動物模型上剖析乾癬表皮細胞的幹細胞動態。結合單一細胞譜系追蹤技術，我們將探討表皮幹細胞在乾癬的調控機制。透過對於幹細胞動態的分析，我們也會利用此系統觀察乾癬表皮在治療後是如何改變回到其正常生理細胞動態。為了驗證上述假設，我們將此計劃達以下3個目標: (1)建立一個結合多光子顯微鏡活體影像系統與帶有特殊表皮螢光基因之乾癬動物模型，可長期追蹤細胞動態的平台(2)藉由長期的細胞追蹤影像，清楚勾勒乾癬皮膚的表皮細胞動態 (3)利用上述平台，剖析乾癬表皮細胞動態在治療後如何改變回生理狀態。此研究將可了解在乾癬皮膚中，表皮幹細胞是如何的失調，也將釐清表皮幹細胞對於治療的反應。透過對於幹細胞的研究，將有針對幹細胞調控的機轉發展乾癬治療的新策略。<br> Abstract: Psoriasis is an acquired inflammatory skin disease that is characterized persistent epidermal hyperplasia with epidermal scaling. It affects about 2-3 % in general population and detrimentally affects the life of the patients. The homeostasis of epidermis is maintained by epidermal stem cells located in the basal layer. How epidermal stem cells become dysregulated in psoriasis is rarely explored and remains poorly understood. It was proposed that epidermis is composed of numerous epidermal proliferative units (EPU). In each EPU, slow-cycling epidermal stem cells produce fast-cycling transit amplifying cells whose proliferation compensate for the continuous loss of epidermal cells due to differentiation and shedding. How epidermal stem cells respond to the inflammatory environment of psoriasis is unknown. In psoriasis, a commonly proposed hypothesis is that epidermal stem cells within each EPU produce a higher number of transit amplifying cells whose higher proliferative character leads to epidermal hyperplasia. However, such hypothesis has never been tested. Recently, through lineage tracing and live imaging, it is proposed that the epidermis in physiological state contains only one type of progenitors and there is no transit amplifying cells. These new methods have never been employed to dissect the stem cell dynamics in psoriasis. In this proposal, we aspire to explore the changes of cellular dynamics of epidermis in psoriasis. By using a fluorescent mouse model for psoriasis induction, we will perform intravital imaging with multiphoton microscopy to characterize the epidermal cellular dynamics. Combined with single cell lineage tracing, we will test the current hypothesis that epidermal hyperplasia in psoriasis is caused by the expansion of transit amplifying cells in the epidermis. By using this model, we will also characterize how the psoriasis skin restores its physiological cellular dynamics after treatment. To test the hypothesis, there are 3 aims in this proposal: (1) To set up a psoriatic model in transgenic mice with specific epidermal nuclear fluorescence and a multiphoton imaging platform for long-term imaging of cellular dynamics. (2) To characterize the cellular dynamics in psoriatic skin by long-term cellular imaging and cell tracing. (3) To explore how epidermal cellular dynamics is reverted to a physiological state in response to treatment by using this mouse model and imaging platform. This work will shed light on how the cellular dynamics of epidermal stem cells is altered in psoriasis and how stem cells in psoriasis respond to treatment. In addition, the results from this study may provide new insight for pharmacological development to modulate the epidermal stem cell activity in psoriasis for treatment.乾癬表皮幹細胞短暫分裂細胞細胞動態多光子顯微鏡活體影像psoriasisepidermal stem celltransit amplifying cellcell dynamicsmultiphoton microscopeintravital imaging