HIV-1 Vpr Inhibits Kaposi's Sarcoma-Associated Herpesvirus Lytic Replication by Inducing MicroRNA miR-942-5p and Activating NF-κB Signaling

Abstract

Kaposi's sarcoma-associated herpesvirus (KSHV) infection is required for the development of several AIDS-related malignancies, including Kaposi's sarcoma (KS) and primary effusion lymphoma (PEL). The high incidence of AIDS-KS has been ascribed to the interaction of KSHV and HIV-1. We have previously shown that HIV-1-secreted proteins Tat and Nef regulate the KSHV life cycle and synergize with KSHV oncogenes to promote angiogenesis and tumorigenesis. Here, we examined the regulation of KSHV latency by HIV-1 viral protein R (Vpr). We found that soluble Vpr inhibits the expression of KSHV lytic transcripts and proteins, as well as viral particle production by activating NF-B signaling following internalization into PEL cells. By analyzing the expression profiles of microRNAs combined with target search by bioinformatics and luciferase reporter analyses, we identi- Kaposi's sarcoma-associated herpesvirus (KSHV), also known as human herpesvirus 8 (HHV-8), is the causative agent of Kaposi's sarcoma (KS). AIDS-associated Kaposi's sarcoma (AIDS-KS) remains a clinical challenge in sub-Saharan Africa and the United States, including a subset of AIDS patients receiving highly active antiretroviral therapy (HAART) (1-4). KSHV infection is also linked to two B-cell lymphoproliferative disorders associated with AIDS, including primary effusion lymphoma (PEL) and a subset of multicentric Castleman's disease (MCD) (5, 6).KSHV displays two distinct replication phases: a latent phase and a productive lytic phase. Following acute infection, KSHV in general establishes lifetime persistence in the infected individuals. During the latent phase, only a limited number of viral genes are expressed, which serve to maintain the persistence of the viral genome, restrict host immune responses, and enhance cell survival. KSHV latently infected cells can be reactivated into lytic replication by several intracellular or extracellular stimuli, such as hypoxia, oxidative stress, and certain cytokines (7-10). Activation of viral lytic replication results in the expression of viral lytic genes and the production of infectious virions (11). Both latent and lytic replication phases are crucial for the long-term persistence of KSHV in the host, and their gene products play critical roles in the pathogenesis of KSHV-associated disease.As is true of infection with other human oncogenic viruses, KSHV infection alone is not sufficient to cause KSHV-associated malignancy (1, 12). Previously, we and others demonstrated that other cofactors, such as human herpesvirus 6 (HHV-6), herpes simplex virus 1 (HSV-1), human immunodeficiency virus type 1

Upregulation of MicroRNA 711 Mediates HIV-1 Vpr Promotion of Kaposi's Sarcoma-Associated Herpesvirus Latency and Induction of Pro-proliferation and Pro-survival Cytokines by Targeting the Notch/NF-κB-Signaling Axis

“…HIV-1 Vpr inhibits KSHV lytic replication and induces pro-proliferative and -survival cytokines by inactivating Notch signaling. Our previous study has indicated that, following internalization into PEL cells, HIV-1 soluble Vpr protein inhibits KSHV lytic replication by activating NF-B signaling (23). Other studies have shown that KSHV can hijack the Notch signaling pathway to maintain the viral life cycle and determine the fate of adjacent cells (27,31).…”

“…A cellular miR-711 directly targets Notch1 3=UTR. We have previously shown that soluble Vpr upregulates cellular miR-942-5p, which directly targets IB␣ 3= untranslated region (UTR) to inhibit KSHV lytic replication in PEL cells (23). To explore whether Notch signaling was also regulated by miRNAs during Vpr inhibition of KSHV lytic replication and induction of pro-proliferation and -survival cytokines, we analyzed previously identified Vpr-regulated miRNAs (23) using miRNA target prediction software, including PITA, RNA hybrid, and RNA22.…”

HIV-1 Tat Interacts with a Kaposi’s Sarcoma-Associated Herpesvirus Reactivation-Upregulated Antiangiogenic Long Noncoding RNA, LINC00313, and Antagonizes Its Function

“…Since the KS lesion is of endothelial cell origin and HIV does not directly infect endothelial cells, studies have focused on elucidating the circulating soluble HIV proteins that may potentiate neoplastic processes (24)(25)(26)(27)(43)(44)(45). Previous reports indicated that viral proteins secreted by HIV-infected cells may be taken up by KSHV-infected cells and consequently dysregulate the KSHV latent to lytic infection switch (39,46) and promote disease progression (24-27, 43, 45). However, it should be note that KS tumor cells are almost exclusively latently infected (1)(2)(3)(4)(5).…”

“…**, P Ͻ 0.01; ***, P Ͻ 0.005 (Student's t test). (39) or downregulated (8) by HIV Tat treatment upon KSHV reactivation, respectively. As shown in Fig.…”

Kaposi's sarcoma‐associated herpesvirus (KSHV)‐encoded microRNAs promote matrix metalloproteinases (MMPs) expression and pro‐angiogenic cytokine secretion in endothelial cells

“…Transfection was performed with 20 nM miRNA mimics using the Effectence Transfection reagent (Qiagen, Valencia, CA) following the manufacturer's instructions. Luciferase reporter assay was performed as previously described . Briefly, HEK293T cells (1 × 10 5 ) were co‐transfected with miRNA mimics, and Renilla vector pRL‐TK (Promega, Madison, WI) using Lipofectamine TM 2000 (Invitrogen, Carlsbad, CA) following the manufacturer's instructions, and then harvested at 24 h post‐transfection.…”