RESUMEN
Epstein-Barr virus (EBV) is a ubiquitous human γ-herpesvirus that establishes life-long infection and increases the risk for the development of several cancers and autoimmune diseases. The mechanisms by which chronic EBV infection leads to subsequent disease remain incompletely understood. Lytic reactivation plays a central role in the development of EBV-driven cancers and may contribute to other EBV-associated diseases. Thus, the clinical use of antivirals as suppressive therapy for EBV lytic reactivation may aid efforts aimed at disease prevention. Current antivirals for EBV have shown limited clinical utility due to low potency or high toxicity, leaving open the need for potent antivirals suitable for long-term prophylaxis. In the present study, we show that tenofovir disoproxil fumarate (TDF) and tenofovir alafenamide (TAF), drugs with excellent safety profiles used clinically for HIV prevention, inhibit EBV lytic DNA replication, with respective IC50 values of 0.30 µM and 84 nM. In a cell-based assay, TAF was 35- and 24-fold and TDF was 10- and 7-fold more potent than acyclovir and penciclovir, respectively, and TAF was also twice as potent as ganciclovir. The active metabolite of tenofovir prodrugs, tenofovir-diphosphate, inhibited the incorporation of dATP into a primed DNA template by the EBV DNA polymerase in vitro. In contrast to acyclovir, treatment of cells during latency for 24 h with TAF still inhibited EBV lytic DNA replication at 72 h after drug was removed. Our results suggest that tenofovir prodrugs may be particularly effective as inhibitors of EBV lytic reactivation, and that clinical studies to address critical questions about disease prevention are warranted.
Asunto(s)
Antivirales/farmacología , Replicación del ADN/efectos de los fármacos , Infecciones por Virus de Epstein-Barr/virología , Herpesvirus Humano 4/efectos de los fármacos , Inhibidores de la Síntesis del Ácido Nucleico/farmacología , Tenofovir/farmacología , Proteínas Virales/antagonistas & inhibidores , ADN Viral/genética , ADN Viral/metabolismo , ADN Polimerasa Dirigida por ADN/genética , ADN Polimerasa Dirigida por ADN/metabolismo , Herpesvirus Humano 4/enzimología , Herpesvirus Humano 4/genética , Herpesvirus Humano 4/fisiología , Humanos , Profármacos/farmacología , Proteínas Virales/genética , Proteínas Virales/metabolismo , Replicación Viral/efectos de los fármacosRESUMEN
The genetic architecture of multiple sclerosis (MS) is similar to that of coeliac disease, with human leukocyte antigen (HLA) being the greatest genetic determinant in both diseases. Furthermore, similar to the involvement of gluten in coeliac disease, Epstein-Barr virus (EBV) infection is now widely considered to be an important environmental factor in MS. The molecular basis for the HLA association in coeliac disease is well defined, and B cells have a clear role in antigen presentation to gluten-specific CD4+ T cells. By contrast, the mechanisms underlying the HLA association of MS are unknown but accumulating evidence indicates a similar role of B cells acting as antigen-presenting cells. The growing parallels suggest that much could be learned about the mechanisms of MS by using coeliac disease as a model. In this Perspective article, we discuss the insights that could be gained from these parallels and consider the possibility of antiviral treatment against EBV as a therapy for MS that is analogous to the gluten-free diet in coeliac disease.
RESUMEN
Proinflammatory cytokines, such as (IL: interleukin) IL-6 and IL-17A, and complement fixation are critical in the immunopathogenesis of neuromyelitis optica spectrum disorders (NMOSD). Blocking the IL-6 receptor or the C5 complement pathway reduces relapse risk. However, the role of interleukin (IL)-6 and complement in aquaporin-4 (AQP4) autoimmunity remains unclear. To investigate the role of the anti-AQP4 immunoglobulin (AQP4-IgG)/AQP4 immunocomplex on the induction and profile of ex vivo cytokine and surface marker expression in peripheral blood mononuclear cells (PBMC) culture. Isolated PBMCs obtained from 18 patients with AQP4-IgG-seropositive-NMOSD (8 treatment-naive, 10 rituximab-treated) or ten healthy controls were cultured with AQP4-immunocomplex with or without complement. Changes in PBMC surface markers and cytokine expression were profiled using flow cytometry and ELISA. PBMCs derived from treatment-naive NMOSD patients stimulated with a complex mixture of serum complement proteins produced significant elevations of IL-17A and IL-6. Rituximab-treated patients also exhibited higher IL-6 but not IL-17A release. IL-6 and IL-17A elevations are not observed without complement. Co-stimulation of PBMCs with AQP4-IgG/AQP4 immunocomplex and complement prompts a Th17-biased response consistent with the inflammatory paradigm observed in NMOSD. A possible inflammation model is proposed via antigen-specific autoreactive peripheral blood cells, including NK/NKT cells.
Asunto(s)
Neuromielitis Óptica , Humanos , Citocinas/metabolismo , Complejo Antígeno-Anticuerpo/metabolismo , Leucocitos Mononucleares/metabolismo , Interleucina-17/metabolismo , Interleucina-6/metabolismo , Rituximab/farmacología , Rituximab/uso terapéutico , Rituximab/metabolismo , Autoanticuerpos , Acuaporina 4 , Proteínas del Sistema Complemento/metabolismo , Inmunoglobulina G/metabolismoRESUMEN
Although the influence of context-dependent endothelial cell (EC) regulation of vascular disease and repair is well-established, the privileged roles ECs play as paracrine regulators of tumor progression has only recently become appreciated. We hypothesized that if the same endothelial physiology governs vascular and cancer biology then EC control in cancer should follow endothelial regulation of vascular health. Healthy ECs promote vascular repair and inhibit tumor invasiveness and metastasis. Dysfunctional ECs have the opposite effects in vascular disease, and we now ask if dysfunctionally activated ECs will promote cancer cell inflammatory signaling and aggressive properties. Indeed, while factors released from quiescent ECs induce balanced inflammatory signaling, correlating with decreased proliferation and invasiveness, factors released from dysfunctional ECs robustly activated NF-κB and STAT3 signaling within cancer cells, correlating with increased in vitro invasiveness and decreased proliferation and survival. Furthermore, matrix-embedded dysfunctional ECs stimulated intratumoral pro-inflammatory signaling and spontaneous metastasis, while simultaneously slowing primary tumor growth, when implanted adjacent to Lewis lung carcinoma tumors. These studies may broaden our appreciation of the roles of endothelial function and dysfunction, increase understanding and control of the tumor microenvironment, and facilitate optimization of anti-angiogenic and vascular-modifying therapies in cancer and other diseases.
Asunto(s)
Células Endoteliales/fisiología , Inflamación/etiología , Metástasis de la Neoplasia , Neoplasias/patología , Animales , Apoptosis , Proliferación Celular , Células Cultivadas , Femenino , Humanos , Ratones , Ratones Endogámicos C57BL , Invasividad Neoplásica , Fenotipo , Transcriptoma , Microambiente TumoralAsunto(s)
Infecciones por VIH , Esclerosis Múltiple , Humanos , Tenofovir/uso terapéutico , Esclerosis Múltiple/complicaciones , Esclerosis Múltiple/diagnóstico por imagen , Esclerosis Múltiple/tratamiento farmacológico , Infecciones por VIH/complicaciones , Infecciones por VIH/tratamiento farmacológicoRESUMEN
We present the case of an HIV-negative patient clinically diagnosed with relapsing-remitting MS who achieved significant disease improvement on Combivir (zidovudine/lamivudine). Within months of treatment, the patient reported complete resolution of previously unremitting fatigue and paresthesiae, with simultaneous improvements in lesion burden detected by MRI. All improvements have been sustained for more than three years. This response may be related to the action of zidovudine as a known inhibitor of EBV lytic DNA replication, suggesting future directions for clinical investigation.