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Külekci B, Schwarz S, Brait N, Perkmann-Nagele N, Jaksch P, Hoetzenecker K, Puchhammer-Stöckl E, Goerzer I. Human cytomegalovirus strain diversity and dynamics reveal the donor lung as a major contributor after transplantation. Virus Evol 2022; 8:veac076. [PMID: 36128049 PMCID: PMC9477073 DOI: 10.1093/ve/veac076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 07/05/2022] [Accepted: 08/23/2022] [Indexed: 11/17/2022] Open
Abstract
Mixed human cytomegalovirus (HCMV) strain infections are frequent in lung transplant recipients (LTRs). To date, the influence of the donor (D) and recipient (R) HCMV serostatus on intra-host HCMV strain composition and viral population dynamics after transplantation is only poorly understood. Here, we investigated ten pre-transplant lungs from HCMV-seropositive donors and 163 sequential HCMV-DNA-positive plasma and bronchoalveolar lavage samples from fifty LTRs with multiviremic episodes post-transplantation. The study cohort included D+R+ (38 per cent), D+R- (36 per cent), and D-R+ (26 per cent) patients. All samples were subjected to quantitative genotyping by short amplicon deep sequencing, and twenty-four of them were additionally PacBio long-read sequenced for genotype linkages. We find that D+R+ patients show a significantly elevated intra-host strain diversity compared to D+R- and D-R+ patients (P = 0.0089). Both D+ patient groups display significantly higher viral population dynamics than D- patients (P = 0.0061). Five out of ten pre-transplant donor lungs were HCMV DNA positive, whereof three multiple HCMV strains were detected, indicating that multi-strain transmission via lung transplantation is likely. Using long reads, we show that intra-host haplotypes can share distinctly linked genotypes, which limits overall intra-host diversity in mixed infections. Together, our findings demonstrate donor-derived strains as the main source of increased HCMV strain diversity and dynamics post-transplantation. These results foster strategies to mitigate the potential transmission of the donor strain reservoir to the allograft, such as ex vivo delivery of HCMV-selective immunotoxins prior to transplantation to reduce latent HCMV.
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Affiliation(s)
- Büsra Külekci
- Center for Virology, Medical University of Vienna, Kinderspitalgasse 15, Vienna 1090, Austria
| | - Stefan Schwarz
- Department of Thoracic Surgery, Medical University of Vienna, Währinger Gürtel 18-20, Vienna 1090, Austria
| | - Nadja Brait
- Cluster of Microbial Ecology, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Nijenborgh 7, Groningen 9747 AG, The Netherlands
| | - Nicole Perkmann-Nagele
- Division of Clinical Virology, Medical University of Vienna, Währinger Gürtel 18-20, Vienna 1090, Austria
| | - Peter Jaksch
- Department of Thoracic Surgery, Medical University of Vienna, Währinger Gürtel 18-20, Vienna 1090, Austria
| | - Konrad Hoetzenecker
- Department of Thoracic Surgery, Medical University of Vienna, Währinger Gürtel 18-20, Vienna 1090, Austria
| | | | - Irene Goerzer
- Center for Virology, Medical University of Vienna, Kinderspitalgasse 15, Vienna 1090, Austria
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Berg C, Wedemeyer MJ, Melynis M, Schlimgen RR, Hansen LH, Våbenø J, Peterson FC, Volkman BF, Rosenkilde MM, Lüttichau HR. The non-ELR CXC chemokine encoded by human cytomegalovirus UL146 genotype 5 contains a C-terminal β-hairpin and induces neutrophil migration as a selective CXCR2 agonist. PLoS Pathog 2022; 18:e1010355. [PMID: 35271688 PMCID: PMC8939814 DOI: 10.1371/journal.ppat.1010355] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 03/22/2022] [Accepted: 02/09/2022] [Indexed: 11/19/2022] Open
Abstract
Human cytomegalovirus (HCMV) is a major pathogen in immunocompromised patients. The UL146 gene exists as 14 diverse genotypes among clinical isolates, which encode 14 different CXC chemokines. One genotype (vCXCL1GT1) is a known agonist for CXCR1 and CXCR2, while two others (vCXCL1GT5 and vCXCL1GT6) lack the ELR motif considered crucial for CXCR1 and CXCR2 binding, thus suggesting another receptor targeting profile. To determine the receptor target for vCXCL1GT5, the chemokine was probed in a G protein signaling assay on all 18 classical human chemokine receptors, where CXCR2 was the only receptor being activated. In addition, vCXCL1GT5 recruited β-arrestin in a BRET-based assay and induced migration in a chemotaxis assay through CXCR2, but not CXCR1. In contrast, vCXCL1GT1 stimulated G protein signaling, recruited β-arrestin and induced migration through both CXCR1 and CXCR2. Both vCXCL1GT1 and vCXCL1GT5 induced equally potent and efficacious migration of neutrophils, and ELR vCXCL1GT4 and non-ELR vCXCL1GT6 activated only CXCR2. In contrast to most human chemokines, the 14 UL146 genotypes have remarkably long C-termini. Comparative modeling using Rosetta showed that each genotype could adopt the classic chemokine core structure, and predicted that the extended C-terminal tail of several genotypes (including vCXCL1GT1, vCXCL1GT4, vCXCL1GT5, and vCXCL1GT6) forms a novel β-hairpin not found in human chemokines. Secondary NMR shift and TALOS+ analysis of vCXCL1GT1 supported the existence of two stable β-strands. C-terminal deletion of vCXCL1GT1 resulted in a non-functional protein and in a shift to solvent exposure for tryptophan residues likely due to destabilization of the chemokine fold. The results demonstrate that non-ELR chemokines can activate CXCR2 and suggest that the UL146 chemokines have unique C-terminal structures that stabilize the chemokine fold. Increased knowledge of the structure and interaction partners of the chemokine variants encoded by UL146 is key to understanding why circulating HCMV strains sustain 14 stable genotypes. Human cytomegalovirus (HCMV) is a prevalent herpesvirus infecting an estimated 60% of the human population worldwide. It is commonly transmitted during early childhood and leads to life-long latency, where viral reactivation can cause severe complications in case of host immune suppression. Furthermore, HCMV is the leading cause of congenital infections. Circulating HCMV strains exhibit great genetic diversity unusual for DNA viruses. One of its most diverse genes is UL146, which encodes a chemokine that facilitates viral dissemination by exploiting the human immune system through mimicry of key immunity components. In this study, we investigate how the diversity of UL146 affects its signaling and structural properties to understand why its genetic diversity is maintained across human populations. We find that certain genotypes that lack key structural domains present in the human homologs nonetheless exert similar functions in the virus-host relationship. Furthermore, many of the UL146 genotypes contain novel structural elements critical for correct protein folding and with the potential to provide HCMV with additional immune modulatory and evasive features. Together, our data highlight a considerable degree of host-adaptation by HCMV and propose novel structural interactions with implications for the virus-host interplay.
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Affiliation(s)
- Christian Berg
- Laboratory for Molecular Pharmacology, Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Copenhagen, Denmark
- Unit for Infectious Diseases, Department of Medicine, Herlev-Gentofte Hospital, University of Copenhagen, Herlev, Denmark
| | - Michael J. Wedemeyer
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Motiejus Melynis
- Laboratory for Molecular Pharmacology, Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Copenhagen, Denmark
| | - Roman R. Schlimgen
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Lasse H. Hansen
- Department of Clinical Biochemistry, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
- Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Copenhagen N, Denmark
| | - Jon Våbenø
- Helgeland Hospital Trust, Sandnessjøen, Norway
| | - Francis C. Peterson
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Brian F. Volkman
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Mette M. Rosenkilde
- Laboratory for Molecular Pharmacology, Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Copenhagen, Denmark
- * E-mail: (MMR); (HRL)
| | - Hans R. Lüttichau
- Laboratory for Molecular Pharmacology, Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Copenhagen, Denmark
- Unit for Infectious Diseases, Department of Medicine, Herlev-Gentofte Hospital, University of Copenhagen, Herlev, Denmark
- * E-mail: (MMR); (HRL)
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