探討胰島與內皮細胞相互作用以促進人工胰島設計

Abstract

糖尿病是一種常見的代謝性疾病，主要由胰島β細胞分泌胰島素分泌不足或組織對胰島素的抵抗所導致。胰島移植是一種有潛力的治療方式能即時調控血糖，但由於供體胰島缺乏、免疫排斥及移植物存活率低等問題，限制了胰島移植作為改善糖尿病的應用。人工胰島技術與多能幹細胞的應用潛力嘗試解決這些問題，但胰島移植後血管化重建方面仍面臨挑戰。因此，了解原生胰島微環境中各個成分的重要性以及它們之間的相互作用對於進一步改善人工胰島的功能具有重要意義。 為了了解胰島與內皮細胞之間的相互作用，並分析胰島微環境中β細胞與內皮細胞之間的細胞間相互作用。我們首先觀察了胰島對內皮細胞增加、遷移行為及其空間分佈的變化，發現內皮細胞在共培養條件下表現出向胰島的趨向性，且內皮細胞的數量增加和與胰島的距離呈負相關，顯示胰島對血管內皮細胞具有明顯的調節作用，並可能促進血管化重建的初期過程。此外，免疫螢光染色分析Connexin36(Cx36)與Connexin43(Cx43)在胰島中的分布，顯示Cx36主要分佈於β細胞的細胞膜及細胞質，而Cx43則主要分布於內皮細胞的邊緣。但我們在免疫金標記的實驗中未觀察到由Cx36與Cx43配對組成的間隙連接，這表示這兩種Connexin可能在β細胞與內皮細胞上各自發揮作用，而非在這兩種細胞間的介面參與間隙連接的細胞間通訊。 本研究探討了胰島和內皮細胞的相互影響，包括內皮細胞對胰島的趨向性。關於Cx36和Cx43在胰島微環境中的分佈情況，雖然我們未能觀察到它們在β細胞與內皮細胞間形成間隙連接，但這些結果為理解胰島內部的細胞間通訊提供了不同的見解。這些發現有助於理解如何促進內皮細胞在人工胰島中的整合，並有助於改善血管化過程，從而提升人工胰島的功能和存活率。

Diabetes mellitus is a common metabolic disorder. It primarily caused by insufficient insulin release from pancreatic islet β-cells or peripheral insulin resistance. Islet transplantation has emerged as a promising treatment offering real-time glucose monitoring and insulin release, potentially restoring glucose regulation. However, its application is limited by several challenges such as donor shortages, immune rejection and low graft survival rates after transplantation. The application potential of artificial islet technology and pluripotent stem cells attempted to alleviate these problems, but revascularization after islet transplantation remains a major challenge. Therefore, understanding the importance of various components within the native islet microenvironment and their interactions is crucial for further improving the functionality of artificial islets. To investigate the interactions between islets and endothelial cells and analyze the intercellular interactions between β-cells and endothelial cells in the islet microenvironment, we first observed changes in endothelial cell count, behavior and spatial distribution. We found that endothelial cells exhibited a tropism toward islets in co-culture experiment. The density of endothelial cells increased is negative correlation with the distance from the islets. It suggested that islets have regulatory effects on endothelial cells and may promote the initial processes for supporting islet revascularization. Additionally, immunofluorescence staining was used to analyze the distribution of Connexin36 (Cx36) and Connexin43 (Cx43) within islets. Cx36 was primarily expressed on the cell membrane and cytoplasm of β-cells, while Cx43 was expressed on the cell membrane, especially at the contact interface between adjacent cells. However, we did not observe gap junctions formed by the pairing of Cx36 and Cx43 in immunogold labeling experiments. This suggested that these two Connexins may function individually on β cells and endothelial cells, rather than participating in gap junction-mediated intercellular communication at the interface between the two cell types. Our study investigates the interaction between islets and endothelial cells, including endothelial cell tropism toward islets. Regarding the distribution of Cx36 and Cx43 in the islet microenvironment, although we did not observe gap junction formed by Cx36 and Cx43 paired between β-cells and endothelial cells, these findings provide alternative insights into intercellular communication within the islet. These results valuable for understanding how to enhance endothelial cell integration within artificial islets and improve the revascularization process, which may increase the functionality and survival rate of artificial islets.