INSERM UMR 866, Equipe labellisée, Ligue Nationale contre le Cancer, and Laboratoire d'Excellence LipSTIC, Dijon, France.
Université de Bourgogne Franche-Comté, LNC UMR 866, Dijon, France.
JCI Insight. 2017 Mar 23;2(6):e90531. doi: 10.1172/jci.insight.90531.
Better identification of severe acute graft-versus-host disease (GvHD) may improve the outcome of this life-threatening complication of allogeneic hematopoietic stem cell transplantation. GvHD induces tissue damage and the release of damage-associated molecular pattern (DAMP) molecules. Here, we analyzed GvHD patients ( = 39) to show that serum heat shock protein glycoprotein 96 (Gp96) could be such a DAMP molecule. We demonstrate that serum Gp96 increases in gastrointestinal GvHD patients and its level correlates with disease severity. An increase in Gp96 serum level was also observed in a mouse model of acute GvHD. This model was used to identify complement C3 as a main partner of Gp96 in the serum. Our biolayer interferometry, yeast two-hybrid and in silico modeling data allowed us to determine that Gp96 binds to a complement C3 fragment encompassing amino acids 749-954, a functional complement C3 hot spot important for binding of different regulators. Accordingly, in vitro experiments with purified proteins demonstrate that Gp96 downregulates several complement C3 functions. Finally, experimental induction of GvHD in complement C3-deficient mice confirms the link between Gp96 and complement C3 in the serum and with the severity of the disease.
更好地识别严重急性移植物抗宿主病（GvHD）可能会改善这种危及生命的异基因造血干细胞移植并发症的预后。GvHD 会导致组织损伤和损伤相关分子模式（DAMP）分子的释放。在这里，我们分析了 GvHD 患者（=39 人），表明血清热休克蛋白糖蛋白 96（Gp96）可能就是这样一种 DAMP 分子。我们证明，胃肠道 GvHD 患者的血清 Gp96 增加，其水平与疾病严重程度相关。在急性 GvHD 的小鼠模型中也观察到 Gp96 血清水平增加。该模型用于鉴定补体 C3 是血清中 Gp96 的主要伴侣。我们的生物层干涉术、酵母双杂交和计算机建模数据使我们能够确定 Gp96 结合了补体 C3 的一个片段，该片段包含 749-954 个氨基酸，这是一个功能补体 C3 热点，对于结合不同的调节剂很重要。因此，用纯化蛋白进行的体外实验表明，Gp96 下调了补体 C3 的几种功能。最后，在补体 C3 缺陷型小鼠中诱导 GvHD 的实验证实了 Gp96 与血清中的补体 C3 及其与疾病严重程度之间的联系。
