Lollinga Wouter T, de Wit Raymond H, Rahbar Afsar, Vasse Gwenda F, Davoudi Belghis, Diepstra Arjan, Riezebos-Brilman Annelies, Harmsen Martin C, Hillebrands Jan-Luuk, Söderberg-Naucler Cecilia, van Son Willem J, Smit Martine J, Sanders Jan-Stephan, van den Born Jacob
1 Division of Nephrology, Department of Internal Medicine, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands. 2 Department of Chemistry and Pharmaceutical Sciences, Division of Medicinal Chemistry, Vrije Universiteit, Amsterdam, the Netherlands. 3 Department of Medicine, Center for Molecular Medicine, Unit for Microbial Pathogenesis, Karolinska Institutet, Solna, Stockholm, Sweden. 4 Division of Pathology, Department of Pathology and Medical Biology, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands. 5 Division of Clinical Virology, Department of Medical Microbiology, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands. 6 Division of Medical Biology, Department of Pathology and Medical Biology, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands.
Transplantation. 2017 Mar;101(3):531-540. doi: 10.1097/TP.0000000000001289.
Renal transplantation is the preferred treatment for patients with end-stage renal disease. Human cytomegalovirus (HCMV) activation is associated with decreased renal graft function and survival. Human cytomegalovirus encodes several immune modulatory proteins, including the G protein-coupled receptor US28, which scavenges human chemokines and modulates intracellular signaling.
Our aim was to identify the expression and localization of US28 in renal allograft biopsies by immunohistochemistry and determine its role in viral spreading in vitro.
Immunohistochemistry revealed US28 in 31 of 34 renal transplant biopsies from HCMV-seropositive donors. Expression was independent of HCMV viremia or IgG serostatus. US28 was predominantly expressed in the cytoplasm of vascular smooth muscle cells (VSMCs) and tubular epithelial cells, with a median positivity of 20% and 40%, respectively. Also, US28-positive cells were present within arterial neointima. In contrast to US28, HCMV-encoded immediate early antigen was detected in less than 5% of VSMCs, tubular epithelial cells, interstitial endothelium, interstitial inflammatory infiltrates, and glomerular cells.Primary VSMCs were infected with green fluorescent protein-tagged wild type or US28-deficient HCMV. The viral spreading of US28-deficient HCMV, via culture medium or cell-to-cell transmission, was significantly impeded as shown by green fluorescent protein (ie, infected) cell quantification and quantitative real-time polymerase chain reaction. Additionally, the number and size of foci was smaller.
In summary, HCMV-encoded US28 was detected in renal allografts from HCMV-positive donors independent of viremia and serostatus. Also, US28 facilitates HCMV spreading in VSMCs in vitro. Because the vasculature is affected in chronic renal transplant dysfunction, US28 may provide a potential target for therapeutic intervention.
肾移植是终末期肾病患者的首选治疗方法。人巨细胞病毒（HCMV）激活与肾移植功能下降和存活率降低有关。人巨细胞病毒编码几种免疫调节蛋白，包括G蛋白偶联受体US28，它能清除人趋化因子并调节细胞内信号传导。
我们的目的是通过免疫组织化学鉴定US28在肾移植活检组织中的表达和定位，并确定其在体外病毒传播中的作用。
免疫组织化学显示，在34例来自HCMV血清阳性供体的肾移植活检组织中，有31例检测到US28。其表达与HCMV病毒血症或IgG血清状态无关。US28主要在血管平滑肌细胞（VSMC）和肾小管上皮细胞的细胞质中表达，中位阳性率分别为20%和40%。此外，动脉新内膜中也存在US28阳性细胞。与US28不同，在不到5%的VSMC、肾小管上皮细胞、间质内皮细胞、间质炎性浸润细胞和肾小球细胞中检测到HCMV编码的立即早期抗原。用绿色荧光蛋白标记的野生型或US28缺陷型HCMV感染原代VSMC。通过绿色荧光蛋白（即感染）细胞定量和定量实时聚合酶链反应显示，US28缺陷型HCMV通过培养基或细胞间传播的病毒扩散明显受阻。此外，病灶的数量和大小更小。
总之，在来自HCMV阳性供体的肾移植中检测到HCMV编码的US28，其与病毒血症和血清状态无关。此外，US28在体外促进HCMV在VSMC中的传播。由于慢性肾移植功能障碍会影响血管系统，US28可能为治疗干预提供一个潜在靶点。
