Cell Isolation and Transplantation Center, Department of Surgery, Faculty Diabetes Center, Geneva University, Hospitals and University of Geneva, Geneva, Switzerland.
Sci Rep. 2020 Apr 24;10(1):7011. doi: 10.1038/s41598-020-64054-9.
Hypoxia, IL-1β production and oxidative stress are involved in islet graft dysfunction and destruction. However, the link between these events has not yet been determined in transplanted islets. The goal of this study was to determine whether NLRP3 inflammasome is responsible for IL-1β production and if it is activated by hypoxia-induced oxidative stress in transplanted islets. Rat islets were transplanted under the kidney capsule of immunodeficient mice. At different times post-transplantation, blood samples were collected and islet grafts harvested. Rat islets were also incubated in vitro either under normoxia or hypoxia for 24 h, in the absence or presence of inhibitors of NLRP3 inflammasome (CASP1 inhibitor) or oxidative stress (NAC). NLRP3, CASP1, IL1B, BBC3 pro-apoptotic and BCL2 anti-apoptotic genes in transplanted and in vitro incubated islets were then studied using real time PCR. IL-1β released in the blood and in the supernatant was quantified by ELISA. Cell death was analysed by propidium iodide and Annexin-V staining. NLRP3, CASP1 and BBC3 in transplanted rat islets and IL-1β in blood transiently increased during the first days after transplantation. In islets incubated under hypoxia, NRLP3, IL1B and CASP1 and IL-1β released in supernatant increased compared to islets incubated under normoxia. These effects were prevented by the inhibition of NLRP3 inflammasome by CASP1 or oxidative stress by NAC. However, these inhibitors did not prevent hypoxia-induced rat islet death. These data show that NLRP3 inflammasome in rat islets is transiently activated after their transplantation and induced through oxidative stress in vitro. However, NRLP3 inflammasome inhibition does not protect islet cells against hypoxia.
缺氧、IL-1β 产生和氧化应激与胰岛移植物功能障碍和破坏有关。然而，这些事件之间的联系在移植的胰岛中尚未确定。本研究的目的是确定 NLRP3 炎性体是否负责 IL-1β 的产生，以及它是否被缺氧诱导的氧化应激激活。将大鼠胰岛移植到免疫缺陷小鼠的肾包膜下。在移植后的不同时间，采集血样并收获胰岛移植物。然后，将大鼠胰岛在体外分别于常氧或缺氧条件下孵育 24 小时，同时存在或不存在 NLRP3 炎性体抑制剂（Caspase1 抑制剂）或氧化应激抑制剂（NAC）。然后使用实时 PCR 研究移植和体外孵育的胰岛中的 NLRP3、Caspase1、IL1B、BBC3 促凋亡和 BCL2 抗凋亡基因。通过 ELISA 定量测定血液和上清液中释放的 IL-1β。通过碘化丙啶和 Annexin-V 染色分析细胞死亡。在移植的大鼠胰岛中，NLRP3、Caspase1 和 BBC3 以及血液中的 IL-1β 在移植后的最初几天内短暂增加。与常氧孵育的胰岛相比，在缺氧条件下孵育的胰岛中，NRLP3、IL1B 和 Caspase1 以及上清液中释放的 IL-1β 增加。这些作用通过 Caspase1 抑制 NLRP3 炎性体或 NAC 抑制氧化应激来预防。然而，这些抑制剂不能防止缺氧诱导的大鼠胰岛死亡。这些数据表明，移植后大鼠胰岛中的 NLRP3 炎性体短暂激活，并在体外通过氧化应激诱导。然而，NLRP3 炎性体抑制不能保护胰岛细胞免受缺氧。
