Cytomegalovirus Seropositivity Is Associated With Increased Microbial Translocation in People Living With Human Immunodeficiency Virus and Uninfected Controls
CLINICAL INFECTIOUS DISEASES
Authors: Ramendra, Rayoun; Isnard, Stephane; Lin, John; Fombuena, Brandon; Ouyang, Jing; Mehraj, Vikram; Zhang, Yonglong; Finkelman, Malcolm; Costiniuk, Cecilia; Lebouche, Bertrand; Chartrand-Lefebvre, Carl; Durand, Madeleine; Tremblay, Cecile; Ancuta, Petronela; Boivin, Guy; Routy, Jean-Pierre
Abstract
Background Cytomegalovirus (CMV) seropositivity and anti-CMV immunoglobulin G (IgG) levels are associated with adverse health outcomes in elderly populations. Among people living with human immunodeficiency virus (PLWH), CMV seropositivity has been associated with persistent CD8 T-cell elevation and increased risk of developing non-AIDS comorbidities despite long-term antiretroviral therapy (ART). Herein, we investigated whether CMV seropositivity and elevation of anti-CMV IgG levels were associated with increased epithelial gut damage, microbial translocation, and systemic inflammation. Methods A total of 150 PLWH (79 ART-naive and 71 ART-treated) were compared to 26 without human immunodeficiency virus (HIV) infection (uninfected controls). Plasma markers of HIV disease progression, epithelial gut damage, microbial translocation, nonspecific B-cell activation, anti-CMV and anti-Epstein-Barr virus (EBV) IgG levels, and proinflammatory cytokines were measured. Results CMV seropositivity and elevated anti-CMV IgG levels were associated with markers of epithelial gut damage, microbial translocation, and inflammation in PLWH and participants without HIV infection. In contrast, total nonspecific IgG, immunoglobulin M, immunoglobulin A, and anti-EBV IgG levels were not associated with these markers. CMV seropositivity was associated with markers of epithelial gut damage, microbial translocation, and inflammation independent of sociodemographic and behavioral characteristics of the study population. Conclusions CMV-seropositive people with and without HIV had increased epithelial gut damage, microbial translocation, and inflammation. Furthermore, anti-CMV IgG levels were independently associated with increased epithelial gut damage and microbial translocation. CMV coinfection may partially explain persistent gut damage, microbial translocation, and inflammation in ART-treated PLWH. Cytomegalovirus (CMV) seropositivity and anti-CMV immunoglobulin G levels are associated with increased epithelial gut damage, microbial translocation, and inflammation in antiretroviral therapy (ART)-naive and ART-treated people living with human immunodeficiency virus and uninfected controls.
MDM2's dual mRNA binding domains co-ordinate its oncogenic and tumour suppressor activities
NUCLEIC ACIDS RESEARCH
Authors: Gnanasundram, Sivakumar Vadivel; Malbert-Colas, Laurence; Chen, Sa; Fusee, Leila; Daskalogianni, Chrysoula; Muller, Petr; Salomao, Norman; Fahraeus, Robin
Abstract
Cell growth requires a high level of protein synthesis and oncogenic pathways stimulate cell proliferation and ribosome biogenesis. Less is known about how cells respond to dysfunctional mRNA translation and how this feeds back into growth regulatory pathways. The Epstein-Barr virus (EBV)-encoded EBNA1 causes mRNA translation stress in cis that activates PI3K delta. This leads to the stabilization of MDM2, induces MDM2's binding to the E2F1 mRNA and promotes E2F1 translation. The MDM2 serine 166 regulates the interaction with the E2F1 mRNA and deletion of MDM2 C-terminal RING domain results in a constitutive E2F1 mRNA binding. Phosphorylation on serine 395 following DNA damage instead regulates p53 mRNA binding to its RING domain and prevents the E2F1 mRNA interaction. The p14Arf tumour suppressor binds MDM2 and in addition to preventing degradation of the p53 protein it also prevents the E2F1 mRNA interaction. The data illustrate how two MDM2 domains selectively bind specific mRNAs in response to cellular conditions to promote, or suppress, cell growth and how p14Arf coordinates MDM2's activity towards p53 and E2F1. The data also show how EBV via EBNA1-induced mRNA translation stress targets the E2F1 and the MDM2 - p53 pathway.