Identification and characterization of the anti-viral interferon lambda 3 as direct target of the Epstein-Barr virus microRNA-BART7-3p

ABSTRACT

The human Epstein–Barr virus (EBV), as a member of the human γ herpes viruses (HHV), is known to be linked with distinct tumor types. It is a double-stranded DNA virus and its genome encodes among others for 48 different microRNAs (miRs). Current research demonstrated a strong involvement of certain EBV-miRs in molecular immune evasion mechanisms of infected cells by, e.g., the disruption of human leukocyte antigen (HLA) class Ia and NKG2D functions. To determine novel targets of EBV-miRs involved in immune surveillance, ebv-miR-BART7-3p, an EBV-encoded miR with high expression levels during the different lytic and latent EBV life cycle phases, was overexpressed in human HEK293T cells. Using a cDNA microarray-based comparative analysis, 234 (229 downregulated and 5 upregulated) deregulated human transcripts were identified in ebv-miR-BART7-3p transfectants, which were mainly involved in cellular processes and molecular binding. A statistically significant downregulation of the anti-proliferative and tumor-suppressive hsa-miR-34A and the anti-viral interferon lambda (IFNL)3 mRNA was found. The ebv-miR-BART7-3p-mediated downregulation of IFNL3 expression was due to a direct interaction with the IFNL3 3’-untranslated region (UTR) as determined by luciferase reporter gene assays including the identification of the accurate ebv-miR-BART7-3p binding site. The effect of ebv-miR-BART7-3p on the IFNL3 expression was validated both in human cell lines in vitro and in human tissue specimen with known EBV status. These results expand the current knowledge of EBV-encoded miRs and their role in immune evasion, pathogenesis and malignant transformation.

KEYWORDS:

• EBV
• EBV target genes
• IFNL3
• immune escape
• microRNA

Acknowledgments

We thank Prof. Michael Bachmann (Helmholtz-Zentrum Dresden Rossendorf, Institute of Radiopharmaceutical Cancer Research Dresden, Germany) for his support and Maria Heise for excellent secretarial help.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Author contributions

SJB designed the project and is responsible for the study. Material preparation, data collection including clinical parameters and analysis were performed by MB, CW, AW, JB and SJB. Experimental work was performed by JB, MB, SJB and CV, and the results and their interpretation were discussed by JB, SJB, MB and BS. The first draft of the manuscript was written by SJB, JB, MB and BS. SJB, JB, MB and CV prepared the figures. SJB, CW, OM and BS revised the final version of the manuscript, which was approved by all authors.

Data availability statement

The authors confirm that the data supporting the findings of this study are available within the article and/or its supplementary materials.

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/2162402X.2023.2284483

Additional information

Funding

This article was supported by grants from the German Research Foundation (DFG; project numbers: 496182670 SJB; SE581/34-1 BS), the Jackstädt Foundation (SJB), the Monika Kutzner Foundation (SJB), the German Israelian Foundation (GIF I-1412-414.13-2017; BS, OM) and the BMBF (ZB 031B0800B CW, BS). Funded by the Brandenburg Medical School publication fund supported by the Ministry of Science, Research and Cultural Affairs of the State of Brandenburg.