The Viral G-Protein-Coupled Receptor Homologs M33 and US28 Promote Cardiac Dysfunction during Murine Cytomegalovirus Infection.

Human cytomegalovirus (HCMV) is a ubiquitous pathogen that infects the majority of the world population and causes lifelong latent infection. HCMV has been shown to exacerbate cardiovascular diseases, including myocarditis, vascular sclerosis, and transplant vasculopathy. Recently, we have shown that murine CMV (MCMV) recapitulates the cardiovascular dysfunction observed in patients with HCMV-induced myocarditis.

The CMV-encoded G protein-coupled receptors M33 and US28 play pleiotropic roles in immune evasion and alter host T cell responses.

Introduction: Human cytomegalovirus (HCMV) is a global health threat due to its ubiquity and lifelong persistence in infected people. During latency, host CD8 T cell responses to HCMV continue to increase in a phenomenon known as memory inflation. We used murine CMV (MCMV) as a model for HCMV to characterize the memory inflation response to wild-type MCMV (KP) and a latency-defective mutant (ΔM33), which lacks M33, an MCMV chemokine receptor homolog.

Constitutive Signaling by the Human Cytomegalovirus G Protein Coupled Receptor Homologs US28 and UL33 Enables Trophoblast Migration In Vitro.

Human cytomegalovirus (HCMV) encodes four homologs of G protein coupled receptors (vGPCRs), of which two, designated UL33 and US28, signal constitutively. UL33 and US28 are also conserved with chemokine receptors: US28 binds numerous chemokine classes, including the membrane bound chemokine, fractalkine; whereas UL33 remains an orphan receptor. There is emerging data that UL33 and US28 each contribute to HCMV associated disease, although no studies to date have reported their potential contribution to aberrant placental physiology that has been detected with HCMV congenital infection.

The Mouse Cytomegalovirus G Protein-Coupled Receptor Homolog, M33, Coordinates Key Features of Infection via Distinct Components of Its Signaling Repertoire.

Common to all cytomegalovirus (CMV) genomes analyzed to date is the presence of G protein-coupled receptors (GPCR). Animal models of CMV provide insights into their role in viral fitness. The mouse cytomegalovirus (MCMV) GPCR, M33, facilitates dendritic cell (DC)-dependent viremia, the extravasation of blood-borne infected DCs to the salivary gland, and the frequency of reactivation events from latently infected tissue explants.

Correction: Cross-presentation of a spread-defective MCMV is sufficient to prime the majority of virus-specific CD8+ T cells.

[This corrects the article DOI: 10.1371/journal.pone.

Murine Cytomegalovirus Glycoprotein O Promotes Epithelial Cell Infection .

Cytomegaloviruses (CMVs) establish systemic infections across diverse cell types. Glycoproteins that alter tropism can potentially guide their spread. Glycoprotein O (gO) is a nonessential fusion complex component of both human CMV (HCMV) and murine CMV (MCMV).

Human cytomegalovirus US28 allows dendritic cell exit from lymph nodes.

Human cytomegalovirus (HCMV) colonizes blood-borne dendritic cells (DCs). They express US28, a viral G protein-coupled receptor (GPCR). In vitro functions have been described for US28, but how it contributes to host colonization has been unclear.

Structure-Activity Relationships of GAG Mimetic-Functionalized Mesoporous Silica Nanoparticles and Evaluation of Acyclovir-Loaded Antiviral Nanoparticles with Dual Mechanisms of Action.

Mesoporous silica nanoparticles (MSNs) are drug delivery agents that are able to incorporate drugs within their pores. Furthermore, MSNs can be functionalized by attachment of bioactive ligands on their surface to enhance their activity, and nanoparticles modified with glycosaminoglycan (GAG) mimetics inhibit the entry of herpes simplex virus (HSV) into cells. In this study, structure-activity relationships of GAGs attached to MSNs were investigated in relation to HSV-1 and HSV-2, and acyclovir was loaded into the pores of MSNs.

Murine cytomegalovirus degrades MHC class II to colonize the salivary glands.

Cytomegaloviruses (CMVs) persistently and systemically infect the myeloid cells of immunocompetent hosts. Persistence implies immune evasion, and CMVs evade CD8+ T cells by inhibiting MHC class I-restricted antigen presentation. Myeloid cells can also interact with CD4+ T cells via MHC class II (MHC II).

Murine Cytomegalovirus Spreads by Dendritic Cell Recirculation.

Herpesviruses have coevolved with their hosts over hundreds of millions of years and exploit fundamental features of their biology. Cytomegaloviruses (CMVs) colonize blood-borne myeloid cells, and it has been hypothesized that systemic dissemination arises from infected stem cells in bone marrow. However, poor CMV transfer by stem cell transplantation argues against this being the main reservoir.

Type 1 Interferons and NK Cells Limit Murine Cytomegalovirus Escape from the Lymph Node Subcapsular Sinus.

Cytomegaloviruses (CMVs) establish chronic, systemic infections. Peripheral infection spreads via lymph nodes, which are also a focus of host defence. Thus, this is a point at which systemic infection spread might be restricted.

Luciferase-tagged wild-type and tropism-deficient mouse cytomegaloviruses reveal early dynamics of host colonization following peripheral challenge.

Cytomegaloviruses (CMVs) establish persistent, systemic infections and cause disease by maternal-foetal transfer, suggesting that their dissemination is a key target for antiviral intervention. Late clinical presentation has meant that human CMV (HCMV) dissemination is not well understood. Murine CMV (MCMV) provides a tractable model.

GAG mimetic functionalised solid and mesoporous silica nanoparticles as viral entry inhibitors of herpes simplex type 1 and type 2 viruses.

A glycosaminoglycan mimetic was attached to the surface of solid and mesoporous silica nanoparticles to create novel antiviral agents against herpes simplex type 1 and type 2 viruses. The nanoparticles act as viral entry inhibitors that appear to block viral attachment and penetration into susceptible cells.

Distinct brainstem and forebrain circuits receiving tracheal sensory neuron inputs revealed using a novel conditional anterograde transsynaptic viral tracing system.

Sensory nerves innervating the mucosa of the airways monitor the local environment for the presence of irritant stimuli and, when activated, provide input to the nucleus of the solitary tract (Sol) and paratrigeminal nucleus (Pa5) in the medulla to drive a variety of protective behaviors. Accompanying these behaviors are perceivable sensations that, particularly for stimuli in the proximal end of the airways, can be discrete and localizable. Airway sensations likely reflect the ascending airway sensory circuitry relayed via the Sol and Pa5, which terminates broadly throughout the CNS.

Synergistic activity of tenofovir and nevirapine combinations released from polycaprolactone matrices for potential enhanced prevention of HIV infection through the vaginal route.

Polycaprolactone (PCL) matrices were simultaneously loaded with the antiviral agents, tenofovir (TFV) and nevirapine (NVP), in combination to provide synergistic activity in the prevention of HIV transmission through the vaginal route. TFV and NVP were incorporated in PCL matrices at theoretical loadings of 10%TFV-10% NVP, 5%TFV-5%NVP and 5%TFV-10%NVP, measured with respect to the PCL content of the matrices. Actual TFV loadings ranged from 2.

Evaluation of microporous polycaprolactone matrices for controlled delivery of antiviral microbicides to the female genital tract.

Acyclovir (ACV) as a model antiviral microbicide, was incorporated in controlled-release polycaprolactone (PCL) matrices designed for application as intra-vaginal ring inserts (IVRs). Microporous materials incorporating acyclovir up to a level of ~10 % w/w were produced by rapidly cooling suspensions of drug powder in PCL solution followed by solvent extraction from the hardened matrices. Around 21, 50 and 78 % of the drug content was gradually released from matrices over 30 days in simulated vaginal fluid at 37 °C, corresponding to drug loadings of 5.

Identification of common mechanisms by which human and mouse cytomegalovirus seven-transmembrane receptor homologues contribute to in vivo phenotypes in a mouse model.

The mouse cytomegalovirus chemokine receptor homologue (CKR) M33 is required for salivary gland tropism and efficient reactivation from latency, phenotypes partially rescued by the human cytomegalovirus CKR US28. Herein, we demonstrate that complementation of salivary gland tropism is mediated predominantly by G protein-dependent signaling conserved with that of M33; in contrast, both G protein-dependent and -independent pathways contribute to the latency phenotypes. A novel M33-dependent replication phenotype in cultured bone marrow macrophages is also described.

Structural Diversity in Conserved Regions Like the DRY-Motif among Viral 7TM Receptors-A Consequence of Evolutionary Pressure?

Several herpes- and poxviruses have captured chemokine receptors from their hosts and modified these to their own benefit. The human and viral chemokine receptors belong to class A 7 transmembrane (TM) receptors which are characterized by several structural motifs like the DRY-motif in TM3 and the C-terminal tail. In the DRY-motif, the arginine residue serves important purposes by being directly involved in G protein coupling.

Anterograde neuronal circuit tracing using a genetically modified herpes simplex virus expressing EGFP.

Insights into the anatomical organization of complex neural circuits provide important information about function, and thus tools that facilitate neuroanatomical studies have proved invaluable in neuroscience. Advances in molecular cloning have allowed the production of novel recombinant neuroinvasive viruses for use in transynaptic neural tracing studies. However, the vast majority of these viruses have motility in the retrograde direction only, therefore limiting their use to studies of synaptic input circuitry.

Partial functional complementation between human and mouse cytomegalovirus chemokine receptor homologues.

The human cytomegalovirus (CMV) proteins US28 and UL33 are homologous to chemokine receptors (CKRs). Knockout of the mouse CMV M33 protein (UL33 homologue) results in substantial attenuation of salivary gland infection/replication and reduced efficiency of reactivation from tissue explants. M33-mediated G protein-coupled signaling is critical for the salivary gland phenotype.

The M33 chemokine receptor homolog of murine cytomegalovirus exhibits a differential tissue-specific role during in vivo replication and latency.

M33, encoded by murine cytomegalovirus (MCMV), is a member of the UL33 homolog G-protein-coupled receptor (GPCR) family and is conserved across all the betaherpesviruses. Infection of mice with recombinant viruses lacking M33 or containing specific signaling domain mutations in M33 results in significantly diminished MCMV infection of the salivary glands. To determine the role of M33 in viral dissemination and/or infection in other tissues, viral infection with wild-type K181 virus and an M33 mutant virus, DeltaM33B(T2), was characterized using two different routes of inoculation.

A novel streptococcal integrative conjugative element involved in iron acquisition.

In this study, we determined the function of a novel non-ribosomal peptide synthetase (NRPS) system carried by a streptococcal integrative conjugative element (ICE), ICESe2. The NRPS shares similarity with the yersiniabactin system found in the high-pathogenicity island of Yersinia sp. and is the first of its kind to be identified in streptococci.

Functional analysis of the murine cytomegalovirus chemokine receptor homologue M33: ablation of constitutive signaling is associated with an attenuated phenotype in vivo.

The murine cytomegalovirus (MCMV) M33 gene is conserved among all betaherpesviruses and encodes a homologue of seven-transmembrane receptors (7TMR) with the capacity for constitutive signaling. Previous studies have demonstrated that M33 is important for MCMV dissemination to or replication within the salivary glands. In this study, we probed N- and C-terminal regions of M33 as well as known 7TMR signature motifs in transmembrane (TM) II and TM III to determine the impact on cell surface expression, constitutive signaling, and in vivo phenotype.

A point mutation in a herpesvirus polymerase determines neuropathogenicity.

Infection with equid herpesvirus type 1 (EHV-1) leads to respiratory disease, abortion, and neurologic disorders in horses. Molecular epidemiology studies have demonstrated that a single nucleotide polymorphism resulting in an amino acid variation of the EHV-1 DNA polymerase (N752/D752) is significantly associated with the neuropathogenic potential of naturally occurring strains. To test the hypothesis that this single amino acid exchange by itself influences neuropathogenicity, we generated recombinant viruses with differing polymerase sequences.