Modulation of IL-10-Specific B Cell MicroRNAs by Latent Membrane Protein 1 and Epstein-Barr Virus

Abstract

Post-Transplant Lymphoproliferative Disorder (PTLD) is a potentially fatal side effect of the immunosuppressive agents used to prevent allograft rejection. PTLD is associated with Epstein-Barr Virus (EBV) infection and can result in malignant B cell lymphoma. Latent membrane protein 1 (LMP1), a viral mimic of the B cell costimulatory protein CD40, is the major oncogene of EBV and can usurp host cell pathways to promote cell survival. LMP1 activates the Akt/PI3K signaling pathway to drive IL-10 production, which is essential for the autonomous proliferation of EBV+ B cell lymphomas. MicroRNAs are small, non-coding RNAs that post-transcriptionally regulate gene expression to control cellular events such as differentiation, proliferation, and cell survival. As aberrant expression of microRNAs is found in a variety of human malignancies, our goal was to determine if microRNAs participate in LMP1-induced IL-10 production in PTLD-derived cell lymphomas. To first establish that EBV infection can modulate host cell microRNA, we used Taqman microRNA qPCR arrays to detect the microRNA expression profiles of six B cell tumor lines derived from patients with PTLD, two B cell lines generated by infection with the B95.8 strain of EBV obtained from a patient with mononucleosis, and one EBV-negative B cell line. Expression data was then normalized internally and to the EBV-negative B cell line. Our analysis showed that compared to the EBV-negative B cell line, B cells infected with the benign B95.8 strain of EBV had the altered expression (2-fold) of 294 microRNAs while the PTLD-derived EBV+ B cell lines had the altered expression of 224 microRNAs. Twenty-eight microRNAs were altered in both cases of EBV infection. To examine the specific role of LMP1 in host cell microRNA expression, we used an inducible system of LMP1 activation and expressed different LMP1 molecules in an EBV negative B cell lymphoma line. Activation of the B95.8 form of LMP1 modulated 62 cellular microRNAs and 142 microRNAs were modulated by all five of the PTLD-derived LMP1 molecules. Notably, only 28 microRNAs were modulated by both benign and tumor LMP1. The microRNAs aberrantly regulated by either EBV infection or LMP1 activation were next analyzed with target prediction software for potential binding to the 3´UTR of IL-10.

Overview: Cytomegalovirus and the Herpesviruses in Transplantation

“…It appears that expression of viral microRNAs (miRNAs) may also control aspects of the host cellular gene expression (e.g. LMP1 from EBV appears to control the production of a series of novel miRNAs); alterations in the methylation of viral histone proteins may downregulate lytic gene expression to preserve latency (16)(17)(18)(19). As an alternative, some viral prolytic regulatory proteins are expressed but sequestered outside the nucleus to prevent their activation of expression of host and viral lytic genes.…”

RCMV ALL-03 Model and Study of CMV Pathogenesis in Congenital Infection

“…This infection can appear in different types of cells (Davison et al, 2002;Fishman, 2013) such as bone marrow-derived myeloidprogenitor cells (Bego and St Jeor, 2006;Sinzger et al, 2008). Most of lytic gene expressions are shut down or downregulated through miRNA (Harris-Arnold et al, 2012). The reactivation of the virus was reported in people with suppression of the immune system (Dalen, 2002).…”

What’s New and What’s Hot? Basic Science at the American Transplant Congress 2012

“…This process requires cellular production of interleukin-10 (IL-10) as an autocrine growth factor ( Figure 1). B cells infected with a laboratory strain of EBV have altered expression of over 300 miRNAs while PTLD cells have alteration in an overlapping but distinct group of nearly 400 miRNAs (1). Of the miRNAs produced in an In the presence of the EBV oncogene, LMP1, expression of these miRNAs is inhibited, overriding the inhibition of IL-10 secretion with promotion of the growth of EBV+ B cell lymphomas.…”