Itoh T, Iwahashi S, Shimoda M, Chujo D, Takita M, SoRelle J A, Naziruddin B, Levy M F, Matsumoto S
Baylor Research Institute, Islet Cell Laboratory, Dallas, Texas, USA.
Transplant Proc. 2011 Nov;43(9):3156-60. doi: 10.1016/j.transproceed.2011.09.100.
Discovering a new, accurate, and useful damage marker for isolated islets is critical for avoiding the transplantation of nontherapeutic preparations. Recently, we have reported that islets that contained uniquely high levels of high-mobility group box 1 (HMGB1) protein and cytokine induced damaged islets released HMGB1 in a mouse model. Islets are frequently exposed to hypoxic conditions during organ procurement, organ transportation, islet isolation, and islet storage before transplantation. In the present study, we analyzed HMGB1 expressions in hypoxia-induced damaged mouse islets.
Damaged mouse islets were generated by hypoxic conditions (1% O2, 5% CO(2), and 94% N(2)). HMGB1 expressions and production levels were assessed by quantitative real-time polymerase chain reaction (PCR), Western blotting, and enzyme-linked immunosorbent assay (ELISA) studies. In vivo islet function was analyzed using transplantation assay using streptozotocin-induced diabetic mice.
HMGB1 was mainly stained in the nucleus in the intact islets; however, HMGB1 was present in not only the nucleus, but also the cytoplasm in hypoxia-induced damaged islets. HMGB1 messenger RNA (mRNA) levels were up-regulated in the hypoxia-induced damaged islets, suggesting that HMGB1 was intentionally generated during hypoxia. HMGB1 protein levels in the islets were gradually decreased with time under hypoxic conditions. The amount of released HMGB1 levels and the amount of released HMGB1 levels per hour were significantly increased in damaged (noncurable) islets.
When islets were damaged by hypoxic condition, HMGB1 was synthesized and released from hypoxia-induced damaged islets. The amount of released HMGB1 and/or the amount of released HMGB1 per hour might be a useful marker for detecting damaged islets and might be used for islet potency assay.
发现一种用于分离胰岛的新型、准确且有用的损伤标志物对于避免移植无治疗作用的制剂至关重要。最近，我们报道在一个小鼠模型中，含有独特高水平高迁移率族蛋白B1（HMGB1）的胰岛以及细胞因子诱导损伤的胰岛会释放HMGB1。在器官获取、器官运输、胰岛分离以及移植前的胰岛储存过程中，胰岛经常会暴露于缺氧环境。在本研究中，我们分析了缺氧诱导损伤的小鼠胰岛中HMGB1的表达情况。
通过缺氧条件（1%氧气、5%二氧化碳和94%氮气）制备损伤的小鼠胰岛。通过定量实时聚合酶链反应（PCR）、蛋白质印迹法和酶联免疫吸附测定（ELISA）研究评估HMGB1的表达和产生水平。使用链脲佐菌素诱导的糖尿病小鼠进行移植试验，分析体内胰岛功能。
在完整胰岛中，HMGB1主要定位于细胞核；然而，在缺氧诱导损伤的胰岛中，HMGB1不仅存在于细胞核中，还存在于细胞质中。缺氧诱导损伤的胰岛中HMGB1信使核糖核酸（mRNA）水平上调，表明HMGB1是在缺氧过程中特意产生的。在缺氧条件下，胰岛中HMGB1蛋白水平随时间逐渐降低。受损（不可治愈）胰岛中释放的HMGB1水平以及每小时释放的HMGB1水平显著增加。
当胰岛因缺氧条件受损时，HMGB1会从缺氧诱导损伤的胰岛中合成并释放。释放的HMGB1量和/或每小时释放的HMGB1量可能是检测受损胰岛的有用标志物，可用于胰岛效能测定。
