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Human Cytomegalovirus-Encoded Receptor US28 Is Expressed in Renal Allografts and Facilitates Viral Spreading In Vitro

Lollinga, Wouter T. MSc; de Wit, Raymond H. MSc; Rahbar, Afsar PhD; Vasse, Gwenda F. BSc; Davoudi, Belghis MSc; Diepstra, Arjan MD, PhD; Riezebos-Brilman, Annelies MD, PhD; Harmsen, Martin C.; Hillebrands, Jan-Luuk; Söderberg-Naucler, Cecilia; van Son, Willem J.; Smit, Martine J.; Sanders, Jan-Stephan MD, PhD; van den Born, Jacob PhD

doi: 10.1097/TP.0000000000001289
Original Basic Science-General

Background: 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.

Methods: 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.

Results: 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.

Conclusions: 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.

CMV-encoded US28 is detected in VSMCs, arterial neointima and TECs of renal allografts from CMV-positive donors. US28 facilitates CMV spreading in VSMCs in vitro. US28 may provide a potential target for therapeutic intervention.

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.

Received 16 December 2015. Revision received 7 April 2016.

Accepted 8 April 2016.

Funding provided by the Graduate School of Medical Sciences

The authors declare no conflicts of interest.

W.T.L., R.H.d.W., G.V., A.R., A.R.-B.,M.C.H., J.-L.H.,C.S.-N., W.J.v.S., M.J.S., J.-S.S., and J.v.d.B. made substantial contributions to the conception or design of the work, acquisition, analysis, or interpretation of data for the work, and drafting the work or revising it critically for important intellectual content. B.D. and A.D. made substantial contributions to the acquisition, analysis, or interpretation of data for the work and drafting the work or revising it critically for important intellectual content.

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Correspondence: Wouter Lollinga, MSc, Division of Nephrology, Department of Internal Medicine, University Medical Center Groningen, Hanzeplein 1, 9700RB, Groningen, the Netherlands. (w.t.lollinga@umcg.nl).

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