Human cytomegalovirus (HCMV) replicates in many diverse cell types
, and entry into different cells involves distinct entry mechanisms and different envelope glycoproteins. HCMV glycoprotein gB is ...thought to act as the virus fusogen, apparently after being triggered by different gH/gL proteins that bind distinct cellular receptors or entry mediators. A trimer of gH/gL/gO is required for entry into all cell types, and entry into fibroblasts involves trimer binding to platelet-derived growth factor receptor alpha (PDGFRα). HCMV entry into biologically relevant epithelial and endothelial cells and monocyte-macrophages also requires a pentamer, gH/gL complexed with UL128, UL130, and UL131, and there is evidence that the pentamer binds unidentified receptors. We screened an epithelial cell cDNA library and identified the cell surface protein CD147, which increased entry of pentamer-expressing HCMV into HeLa cells but not entry of HCMV that lacked the pentamer. A panel of CD147-specific monoclonal antibodies inhibited HCMV entry into epithelial and endothelial cells, but not entry into fibroblasts. shRNA silencing of CD147 in endothelial cells inhibited HCMV entry but not entry into fibroblasts. CD147 colocalized with HCMV particles on cell surfaces and in endosomes. CD147 also promoted cell-cell fusion induced by expression of pentamer and gB in epithelial cells. However, soluble CD147 did not block HCMV entry and trimer and pentamer did not bind directly to CD147, supporting the hypothesis that CD147 acts indirectly through other proteins. CD147 represents the first HCMV entry mediator that specifically functions to promote entry of pentamer-expressing HCMV into epithelial and endothelial cells.
Human cytomegalovirus infects nearly 80% of the world's population and causes significant morbidity and mortality. The current method of treatment involves the use of antiviral agents that are prone to resistance and can be highly toxic to patients; currently, there is no vaccine against HCMV available. HCMV infections involve virus dissemination throughout the body, infecting a wide variety of tissues; however, the mechanism of spread is not well understood, particularly with regard to which cellular proteins are utilized by HCMV to establish infection. This report describes the characterization of a newly identified cellular molecule that affects HCMV entry into epithelial and endothelial cells. These results will lead to a better understanding of HCMV pathogenesis and have implications for the development of future therapeutics.
Human cytomegalovirus (HCMV) replication relies on a nucleocapsid coat of the 150 kDa, subfamily-specific tegument phosphoprotein (pp150) to regulate cytoplasmic virion maturation. While recent ...structural studies revealed pp150-capsid interactions, the role of specific amino-acids involved in these interactions have not been established experimentally. In this study, pp150 and the small capsid protein (SCP), one of pp150's binding partners found atop the major capsid protein (MCP), were subjected to mutational and structural analyses. Mutations to clusters of polar or hydrophobic residues along the pp150-SCP interface abolished viral replication, with no replication detected in mutant virus-infected cells. Notably, a single amino acid mutation (pp150 K255E) at the pp150-MCP interface significantly attenuated viral replication, unlike in pp150-deletion mutants where capsids degraded outside host nuclei. These functionally significant mutations targeting pp150-capsid interactions, particularly the pp150 K255E replication-attenuated mutant, can be explored to overcome the historical challenges of developing effective antivirals and vaccines against HCMV infection.
•Mutational analysis of the HCMV pp150 small capsid protein interface.•Pp150 small capsid protein interface mutations inhibited HCMV replication.•Pp150 major capsid protein interface mutations attenuated HCMV replication.
Gliomas are the most prevalent and devastating primary malignant brain tumors in adults. Despite substantial advances in understanding glioma biology, there have been no regulatory drug approvals in ...the US since bevacizumab in 2009 and tumor treating fields in 2011. Recent phase III clinical trials have failed to meet their prespecified therapeutic primary endpoints, highlighting the need for novel therapies. The poor prognosis of glioma patients, resistance to chemo-radiotherapy, and the immunosuppressive tumor microenvironment underscore the need for the development of novel therapies. Gene therapy-based immunotherapeutic strategies that couple the ability of the host immune system to specifically kill glioma cells and develop immunological memory have shown remarkable progress. Two adenoviral vectors expressing Ad-HSV1-TK/GCV and Ad-Flt3L have shown promising preclinical data, leading to FDA approval of a non-randomized, phase I open-label, first in human trial to test safety, cytotoxicity, and immune-stimulatory efficiency in high-grade glioma patients (NCT01811992). This review provides a thorough overview of immune-stimulatory gene therapy highlighting recent advancements, potential drawbacks, future directions, and recommendations for future implementation of clinical trials.
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Lowenstein and colleagues demonstrate that their dual-vector gene therapy remodels the TME by causing glioma cell death, and DC recruitment and differentiation, thereby unleashing an immunologically “hot” microenvironment that favors anti-glioma therapeutic responses. Combining this therapy with immune checkpoint inhibitors, DC vaccines, and CAR-T cells, will further enhance glioma treatment.
Kawasaki disease (KD) is a kind of pediatric vasculitis, whose pathogenesis has not been elucidated until now. Many scholars believe that KD is one type of infectious diseases in the susceptible ...groups. However, no recognized pathogens are confirmed. Human cytomegalovirus (HCMV) is a ubiquitous human herpes virus, which can infect varieties of cells including endothelial cells. Studies reported that the viral protein pUL135 is very important for virus replication, reactivation and immune escape. Therefore, we hypothesize that HCMV pUL135 may have a pathogenic effect on KD.
We first determined pUL135 levels in the serum from KD patients. Next, we examined the effects and mechanisms of pUL135 on endothelial cell proliferation and migration. Finally, we assessed the effect of pUL135 on cardiac inflammation in a KD murine model.
Data showed that pUL135 level was significantly increased in the serum from KD patients compared with the healthy and fever controls. And pUL135 expression in endothelial cells remarkably inhibited cell proliferation, migration and tube formation. Moreover, expression of pUL135 obviously affected actin cytoskeleton. Mechanism investigation substantiated that pUL135 mediated endothelial cell dysfunction via regulating CD2AP. Ultimately, we found that HCMV pUL135 aggravated coronary arteritis in the Candida albicans cell wall extracts (CAWS)-induced KD mouse model.
Our findings imply that HCMV pUL135-mediated endothelial dysfunction plays an important role in exacerbating coronary artery injury in KD conditions.
•HCMV pUL135 aggravated coronary arteritis in the KD mouse model.•HCMV pUL135 inhibited endothelial cell proliferation and migration.•HCMV pUL135 exerted its function via CD2AP.•Our new findings suggest that circulating HCMV pUL135 may be a sensitive predictor for coronary artery injury in KD patients.
Human cytomegalovirus (HCMV) is a herpesvirus that infects between 40% and 95% of the population worldwide, usually without symptoms. The host immune response keeps the virus in a latent stage, ...although HCMV can reactivate in an inflammatory context, which could result in sequential lytic/latent viral cycles during the lifetime and thereby participate in HCMV genomic diversity in humans. The high level of HCMV intra-host genomic variability could participate in the oncomodulatory role of HCMV where the virus will favor the development and spread of cancerous cells. Recently, an oncogenic role of HCMV has been highlighted in which the virus will directly transform primary cells; such HCMV strains are named high-risk (HR) HCMV strains. In light of these new findings, this review defines the criteria that characterize HR-HCMV strains and their molecular as well as the phenotypic impact on the infected cell and its tumor microenvironment.
Human cytomegalovirus (HCMV) is a representative
that establishes persistent infections in humans, and exhibits high seropositivity rates in adults. It has co-evolved with its human host and employs ...various strategies to evade antiviral mechanisms by utilizing a significant portion of its genome. HCMV-encoded proteins and miRNAs have been implicated in regulating these mechanisms, enabling viral survival within the human body. During viral infections, autophagy, a conserved catabolic process essential for cellular homeostasis, acts as an antiviral defense mechanism. Multiple studies have reported that HCMV can modulate autophagy through its proteins and miRNAs, thereby influencing its survival within the host. In this study, we showed the potential involvement of HCMV miRNAs in cellular autophagy. We employed various bioinformatic tools to predict putative HCMV miRNAs that target autophagy-related genes and their corresponding cellular autophagy genes. Our results show that the 3'UTR of autophagy-related genes, including ATG9A, ATG9B, ATG16L2, SQSTM1, and EIF2AK2, harbors potential binding sites for hcmv-miR-UL70-3p. Experimental manipulation involving ectopic expression of hcmv-miR-UL70-3p demonstrated a significant reduction in rapamycin-induced autophagy, with ATG9A as its functional target. These findings establish that hcmv-miR-UL70-3p acts as an autophagy inhibitor by suppressing the expression of ATG9A.
Human Cytomegalovirus (HCMV) is a latent virus widely spread in the human population. Obesity and HCMV infection are associated with immunological changes in T lymphocytes. This study aimed to ...evaluate if the association between overweight/obesity and HCMV infection would influence populations of peripheral blood T lymphocytes.
Plasma and peripheral mononuclear cells were isolated from 111 individuals. The biochemical markers and anti-HCMV IgG were quantified in the plasma. The individuals were classified as eutrophic, overweight or obese, based on their body mass index. The lymphocyte populations helper T cells, cytotoxic T cells, memory T regulatory cells, memory effector T cells, early differentiated effector memory cytotoxic T cells, and terminally differentiated effector memory cytotoxic T cells were quantified by flow cytometry.
Approximately half of the individuals studied (46.5%) were seropositive for HCMV, of which 14.1% were eutrophic, 8.1% overweight, and 24.32% were obese. The results showed a substantial reduction in the CD4:CD8 ratio in patients with overweight or obesity, and an increase in the circulating terminally differentiated effector memory cytotoxic T cells, both associated with HCMV positive serology.
HCMV infection, when associated with weight gain contributes to the profile of immunological senescence mediated by an increase in the number of circulating terminally differentiated cytotoxic T cells.
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•The presence of HCMV infection in obesity contributes to the reduction in the ratio of peripheral CD4:CD8 lymphocytes.•Subject with obesity and HCMV infection shows increase in cellular markers of immunosenescence.•HCMV infection does not contribute to changes in clinical-laboratory parameters in obesity.
Natural killer (NK) cells are innate lymphocytes that provide critical host defense against pathogens and cancer. Originally heralded for their early and rapid effector activity, NK cells have been ...recognized over the last decade for their ability to undergo adaptive immune processes, including antigen-driven clonal expansion and generation of long-lived memory. This review presents an overview of how NK cells lithely partake in both innate and adaptive responses and how this versatility is manifest in human NK cell-mediated immunity.
This report has analyzed the potential role of Human Cytomegalovirus (HCMV) UL24 and UL43 products in modulating the subcellular location of a host restriction factor, SAMHD1, in cells of human ...fibroblast origin. Recent studies have reported that the regulation of SAMHD1 is mediated by the HCMV UL97 product inside the nucleus, and by the CDK pathway when it is located in the cytoplasm of the infected cells but the viral gene products that may involve in cytosolic relocalization remain unknown yet. In the present report, we demonstrate that the HCMV UL24 product interacts with the SAMHD1 protein during infection based on mass spectrometry (MS) data and immunoprecipitation assay. The expression or depletion of the viral UL24 gene product did not affect the subcellular localization of SAMHD1 but when it coexpressed with the viral UL43 gene product, another member of the HCMV US22 family, induced the SAMHD1 cytosolic relocalization. Interestingly, the double deletion of viral UL24 and UL43 gene products impaired the cytosolic translocation and the SAMHD1 was accumulated in the nucleus of the infected cells, especially at the late stage post-infection. Our results provide evidence that the viral UL24 and UL43 gene products play a role in the SAMHD1 subcellular localization during HCMV infection.
Human cytomegalovirus (HCMV) infects a wide variety of human cell types by different entry pathways that involve distinct envelope glycoprotein complexes that include gH/gL, a trimer complex ...consisting of gHgL/gO, and a pentamer complex consisting of gH/gL/UL128/UL130/UL131. We characterized the effects of soluble forms of these proteins on HCMV entry. Soluble trimer and pentamer blocked entry of HCMV into epithelial and endothelial cells, whereas soluble gH/gL did not. Trimer inhibited HCMV entry into fibroblast cells, but pentamer and gH/gL did not. Both trimer and pentamer bound to the surfaces of fibroblasts and epithelial cells, whereas gH/gL did not bind to either cell type. Cell surface binding of trimer and pentamer did not involve heparin sulfate moieties. The ability of soluble trimer to block entry of HCMV into epithelial cells did not involve platelet-derived growth factor PDGFRα, which has been reported as a trimer receptor for fibroblasts. Soluble trimer reduced the amount of virus particles that could be adsorbed onto the surface of epithelial cells, whereas soluble pentamer had no effect on virus adsorption. However, soluble pentamer reduced the ability of virus particles to exit from early endosomes into the cytoplasm and then travel to the nucleus. These studies support a model in which both the trimer and pentamer are required for HCMV entry into epithelial and endothelial cells, with trimer interacting with cell surface receptors other than PDGFR and pentamer acting later in the entry pathway to promote egress from endosomes.
HCMV infects nearly 80% of the world's population and causes significant morbidity and mortality. The current antiviral agents used to treat HCMV infections are prone to resistance and can be toxic to patients, and there is no current vaccine against HCMV available. The data in this report will lead to a better understanding of how essential HCMV envelope glycoproteins function during infection of biologically important cell types and will have significant implications for understanding HCMV pathogenesis for developing new therapeutics.
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