%A Hatton,Olivia %A Smith,Madeline M. %A Alexander,Madison %A Mandell,Melanie %A Sherman,Carissa %A Stesney,Madeline W. %A Hui,Sin Ting %A Dohrn,Gillian %A Medrano,Joselinne %A Ringwalt,Kurt %A Harris-Arnold,Aleishia %A Maloney,Eden M. %A Krams,Sheri M. %A Martinez,Olivia M. %D 2019 %J Frontiers in Microbiology %C %F %G English %K Epstein-Barr virus,ebv,Latent membrane protein 1,LMP1,microRNA,miR- 155,FoxO3a,PI3K %Q %R 10.3389/fmicb.2019.02692 %W %L %M %P %7 %8 2019-November-26 %9 Original Research %# %! LMP1 Regulates miR-155 and FOXO3a %* %< %T Epstein-Barr Virus Latent Membrane Protein 1 Regulates Host B Cell MicroRNA-155 and Its Target FOXO3a via PI3K p110α Activation %U https://www.frontiersin.org/articles/10.3389/fmicb.2019.02692 %V 10 %0 JOURNAL ARTICLE %@ 1664-302X %X Epstein-Barr Virus (EBV) is associated with potentially fatal lymphoproliferations such as post-transplant lymphoproliferative disorder (PTLD), a serious complication of transplantation. The viral mechanisms underlying the development and maintenance of EBV+ B cell lymphomas remain elusive but represent attractive therapeutic targets. EBV modulates the expression of host microRNAs (miRs), non-coding RNAs that regulate gene expression, to promote survival of EBV+ B cell lymphomas. Here, we examined how the primary oncogene of EBV, latent membrane protein 1 (LMP1), regulates host miRs using an established model of inducible LMP1 signaling. LMP1 derived from the B95.8 lab strain or PTLD induced expression of the oncogene miR-155. However, PTLD variant LMP1 lost the ability to upregulate the tumor suppressor miR-193. Small molecule inhibitors (SMI) of p38 MAPK, NF-κB, and PI3K p110α inhibited upregulation of miR-155 by B95.8 LMP1; no individual SMI significantly reduced upregulation of miR-155 by PTLD variant LMP1. miR-155 was significantly elevated in EBV+ B cell lymphoma cell lines and associated exosomes and inversely correlated with expression of the miR-155 target FOXO3a in cell lines. Finally, LMP1 reduced expression of FOXO3a, which was rescued by a PI3K p110α SMI. Our data indicate that tumor variant LMP1 differentially regulates host B cell miR expression, suggesting viral genotype as an important consideration for the treatment of EBV+ B cell lymphomas. Notably, we demonstrate a novel mechanism in which LMP1 supports the regulation of miR-155 and its target FOXO3a in B cells through activation of PI3K p110α. This mechanism expands on the previously established mechanisms by which LMP1 regulates miR-155 and FOXO3a and may represent both rational therapeutic targets and biomarkers for EBV+ B cell lymphomas.