Paredes-Juarez Genaro A, Sahasrabudhe Neha M, Tjoelker Reina S, de Haan Bart J, Engelse Marten A, de Koning Eelco J P, Faas Marijke M, de Vos Paul
University of Groningen, University Medical Center Groningen, Department of Pathology and Medical Biology, Section of Immunoendocrinology, Groningen, 9713 GZ, The Netherlands.
Department of Nephrology, Leiden University Medical Center, Leiden, 2300 RC, The Netherlands.
Sci Rep. 2015 Sep 30;5:14623. doi: 10.1038/srep14623.
In between the period of transplantation and revascularization, pancreatic islets are exposed to low-oxygen and low-nutrient conditions. In the present study we mimicked those conditions in vitro to study the involvement of different cell death processes, release of danger-associated molecular patterns (DAMP), and associated in vitro immune activation. Under low-oxygen and low-nutrient conditions, apoptosis, autophagy and necroptosis occur in human islets. Necroptosis is responsible for DAMP-release such as dsDNA, uric acid, and HMGB1. The sensors of the innate immune system able to recognize these DAMPs are mainly TLR, NOD receptors, and C-type lectins. By using cell-lines with a non-functional adaptor molecule MyD88, we were able to show that the islet-derived DAMPs signal mainly via TLR. Immunoisolation in immunoprotective membranes reduced DAMP release and immune activation via retention of the relative large DAMPs in the capsules. Another effective strategy was suppressing necroptosis using the inhibitor nec-1. Although the effect on cell-survival was minor, nec-1 was able to reduce the release of HMGB1 and its associated immune activation. Our data demonstrate that in the immediate post-transplant period islets release DAMPs that in vitro enhance responses of innate immune cells. DAMP release can be reduced in vitro by immunoisolation or intervention with nec-1.
在移植期和血管重建期之间，胰岛会暴露于低氧和低营养环境中。在本研究中，我们在体外模拟这些条件，以研究不同细胞死亡过程的参与情况、危险相关分子模式（DAMP）的释放以及相关的体外免疫激活。在低氧和低营养条件下，人胰岛会发生凋亡、自噬和坏死性凋亡。坏死性凋亡负责释放如双链DNA、尿酸和高迁移率族蛋白B1（HMGB1）等DAMP。能够识别这些DAMP的先天免疫系统传感器主要是Toll样受体（TLR）、核苷酸结合寡聚化结构域（NOD）受体和C型凝集素。通过使用具有无功能衔接分子髓样分化因子88（MyD88）的细胞系，我们能够证明胰岛来源的DAMP主要通过TLR发出信号。免疫保护膜中的免疫隔离通过将相对较大的DAMP保留在胶囊中减少了DAMP释放和免疫激活。另一种有效策略是使用抑制剂nec-1抑制坏死性凋亡。尽管对细胞存活的影响较小，但nec-1能够减少HMGB1的释放及其相关的免疫激活。我们的数据表明，在移植后的即刻，胰岛会释放DAMP，这些DAMP在体外增强先天免疫细胞的反应。通过免疫隔离或用nec-1干预，可在体外减少DAMP释放。
