Department of Experimental Immunology, Renal Transplant Unit, Academic Medical Center, Amsterdam, The Netherlands.
Nephrol Dial Transplant. 2012 Jul;27(7):2746-54. doi: 10.1093/ndt/gfr690. Epub 2011 Dec 13.
Serine protease inhibitor B9 (serpinB9) protects against granzyme B-mediated apoptosis and could help to reduce tubular damage under inflammatory conditions like interstitial nephritis. Previously, we found that tubular serpinB9 expression was increased during subclinical rejection. Here, we studied the regulation of serpinB9 expression in tubular epithelial cells (TECs) under inflammatory conditions.
SerpinB9 expression was analysed on messenger RNA (mRNA), and protein levels in primary human TECs were stimulated with various cytokines and pattern recognition receptor ligands and in kidney transplant biopsies obtained during different types of viral infection.
Of the inflammatory stimuli tested, only the double-stranded RNA (dsRNA) analogue poly(I:C) promoted serpinB9 mRNA and protein expression. We found that TECs express the viral dsRNA receptors Toll-like receptor 3 (TLR3), melanoma differentiation-associated gene 5 (MDA5) and retinoic acid-inducible gene-I (RIG-I). dsRNA receptor ligands enhanced serpinB9 expression, which involved nuclear factor-kappaB (NF-κB) activation, did not require Type I interferon production and was a direct result of dsRNA receptor-induced gene transcription. In kidney transplants, serpinB9 transcription was increased during infection with cytomegalovirus, Epstein-Barr virus or BK virus compared to stable grafts. Immunohistochemistry showed that tubuli and lymphocytes expressed the inhibitor.
SerpinB9 expression in human TECs is induced by triggering of the viral dsRNA sensors TLR3, MDA5 and RIG-I. Viral dsRNA may increase the threshold for granzyme B-mediated apoptosis in TECs via serpinB9 upregulation and thus help to protect the kidney against cytotoxic insults during viral infection.
丝氨酸蛋白酶抑制剂 B9（serpinB9）可防止颗粒酶 B 介导的细胞凋亡，并有助于减轻间质性肾炎等炎症条件下的肾小管损伤。此前，我们发现亚临床排斥反应期间肾小管 serpinB9 表达增加。在这里，我们研究了炎症条件下肾小管上皮细胞（TEC）中 serpinB9 表达的调节。
在原代人 TEC 中用各种细胞因子和模式识别受体配体刺激，并在不同类型病毒感染期间获得的肾移植活检中分析丝氨酸蛋白酶抑制剂 B9 的信使 RNA（mRNA）和蛋白水平表达。
在所测试的炎症刺激物中，只有双链 RNA（dsRNA）类似物聚肌胞苷酸（poly[I:C]）促进了 serpinB9 mRNA 和蛋白表达。我们发现 TEC 表达病毒双链 RNA 受体 Toll 样受体 3（TLR3）、黑色素瘤分化相关基因 5（MDA5）和视黄酸诱导基因-I（RIG-I）。dsRNA 受体配体增强了 serpinB9 的表达，该表达涉及核因子-kappaB（NF-κB）激活，不需要 I 型干扰素的产生，并且是 dsRNA 受体诱导基因转录的直接结果。在肾移植中，与稳定移植物相比，巨细胞病毒、EB 病毒或 BK 病毒感染期间 serpinB9 转录增加。免疫组织化学显示抑制剂在肾小管和淋巴细胞中表达。
人 TEC 中的 serpinB9 表达是通过触发病毒 dsRNA 传感器 TLR3、MDA5 和 RIG-I 诱导的。病毒 dsRNA 可能通过上调 serpinB9 增加 TEC 中颗粒酶 B 介导的细胞凋亡的阈值，并有助于保护肾脏免受病毒感染期间的细胞毒性损伤。
