HERV-W Research Articles

HERV-W upregulation expression in bipolar disorder and schizophrenia: unraveling potential links to systemic immune/inflammation status

BackgroundBipolar disorder (BD) and schizophrenia (SZ) are the two main mental disorders with unknown etiology that significantly impact individuals’ quality of life. The potential pro-inflammatory role in their pathogenesis is postulated and Human Endogenous Retrovirus W (HERV-W) is an emerging candidate to modulate this pathogenic finding. HERVs, ancient retroviruses in the human genome, may play roles in inflammation and disease pathogenesis. Despite HERVs’ involvement in autoimmune diseases, their influence on mental disorders remains underexplored. Therefore, the aim of this study was to assess the level of HERV-W-env expression and the systemic inflammatory profile through the concentration of IL-2, IL-4, IL-6, IL-10, TNF-α and INF-γ cytokines in BD and SZ patients.ResultsAll participants showed HERV-W-env expression, but its expression was higher in mental disorder patients (p < 0.01) than in control. When separated, SZ individuals exhibited higher HERV-W expression than the control group (p < 0.01). Higher serum levels of TNF-α and IL-10 were found in BD (p = 0.0001 and p = 0.001, respectively) and SZ (p = 0.01) and p = 0.01, respectively) than in the control group, while SZ showed decreased levels IFN-γ and IL-2 as compared to controls (p = 0.05) and BD patients (p = 0.05), respectively. Higher TNF-α/IL-4 and TNF-α/IL-10 ratios, and lower IFN-γ/IL-10 were observed in BD and SZ patients than controls. Significant negative correlation between HERV-W-env expression and IL-10 (r=-0.47 p < 0.05), as well as positive correlations between HERV-W-env expression and TNF-α/IL-10 or IFN-γ/IL-10 ratios (r = 0.48 p < 0.05 and r = 0.46 p < 0.05, respectively) were found in BD patients.ConclusionThese findings suggest not only a potential link between HERV-W-env expression both in BD and SZ, but also a possible involvement of systemic inflammatory status in BD patients.

The evaluation of human endogenous retroviral env expression in normal and cancerous tissues of the breast

Abstract Background: Both internal and external risk factors can accelerate the progression of breast cancer which is the reason why clinicians have tried to find new biomarkers for this health problem. Human endogenous retrovirus-W (HERV-W) can be one of these biomarkers, as it has been mentioned that some genes of this virus are able to have either higher or lower expression in numerous cancerous cells. In this study, we aimed to compare HERV-W envelope expression in breast cancer tissues and normal ones since its effects on this malignancy have not been clear. Materials and Methods: We collected 46 breast cancer tissues and their normal adjacent ones. After extracting the RNA of breast samples, we evaluated the expression of HERV-W envelope syncytin-1 and 2 using quantitative real-time polymerase chain reaction (PCR) in different kinds of breast cancer stages. Results: Data showed that more than 13% of patients had a family history of breast cancer; moreover, approximately half of the tissues were estrogen receptor or progesterone receptor positive. Lymph node metastasis was seen in 52% of the patients, and about 40% of tumors were larger than 2 cm. Real-time PCR showed that syncytin-1 and 2 had upward regulation with (*P &lt; 0.05) and (**P &lt; 0.01), respectively. Conclusion: As the expression of HERV-W Env (syncytin-1, syncytin-2) was higher in breast cancerous tissues in comparison with normal ones, we believe that these genes may have a role to play in monitoring patients suffering from this type of cancer. However, further studies are needed to confirm this hypothesis.

A Replication-Competent Retroviral Vector Expressing the HERV-W Envelope Glycoprotein is a Potential Tool for Cancer Gene Therapy.

The fusogenic membrane glycoprotein (FMG) derived from the human endogenous retrovirus-W (HERV-W) exhibits fusogenic properties, making it a promising candidate for cancer gene therapy. When cells are transfected with HERV-W FMG, they can fuse with neighboring cells expressing the receptor, resulting in the formation of syncytia. These syncytia eventually undergo cell death within a few days. In addition, it has been observed that an HERV-W env mutant, which is truncated after amino acid 483, displays increased fusogenicity compared to the wild-type HERV-W env. In this study, we observed syncytium formation upon transfection of HeLa and TE671 human cancer cells with plasmids containing the HERV-W 483 gene. To explore the potential of a semi-replication-competent retroviral (s-RCR) vector encoding HERV-W 483 for FMG-mediated cancer gene therapy, we developed two replication-defective retroviral vectors: a gag-pol vector encoding HERV-W 483 (MoMLV-HERV-W 483) and an env vector encoding VSV-G (pCLXSN-VSV-G-EGFP). When MoMLV-HERV-W 483 and pCLXSN-VSV-G-EGFP were co-transfected into HEK293T cells to produce the s-RCR vector, gradual syncytium formation was observed. However, the titers of the s-RCR virus remained consistently low. To enhance gene transfer efficiency, we constructed an RCR vector encoding HERV-W 483 (MoMLV-10A1-HERV-W 483), which demonstrated replication ability in HEK293T cells. Infection of A549 and HT1080 human cancer cell lines with this RCR vector induced syncytium formation and subsequent cell death. Consequently, both the s-RCR vector and RCR encoding HERV-W 483 hold promise as valuable tools for cancer gene therapy.

Epstein-Barr Virus and Human Endogenous Retrovirus in Japanese Patients with Autoimmune Demyelinating Disorders.

Multiple sclerosis (MS), neuromyelitis optica spectrum disorder (NMOSD), and myelin oligodendrocytes glycoprotein-antibody disease (MOGAD) are distinct autoimmune demyelinating disorders characterized by varying clinical and pathological characteristics. While the precise origins of these diseases remain elusive, a combination of genetic and environmental factors, including viral elements, have been suggested as potential contributors to their development. Our goal was to assess the occurrence of antibodies against pathogenic peptides associated with Epstein-Barr virus (EBV) and the human endogenous retrovirus-W (HERV-W) in serum samples obtained from Japanese individuals diagnosed with MS, NMOSD, and MOGAD and to make comparisons with a group of healthy controls (HCs). We conducted a retrospective analysis involving 114 Japanese participants, comprising individuals with MS (34), NMOSD (20), MOGAD (20), and HCs (40). These individuals were tested using a peptide-based enzyme-linked immunosorbent assay. A marked increase in antibody response against EBV nuclear antigen 1 (EBNA1)386-405 was observed in the serum of MS and MOGAD patients, as compared to HCs. Notably, we observed a correlation between antibodies against EBNA1386-405 and HERV-W486-504 peptides in a subset of the antibody-positive MS patients. These findings emphasize the involvement of EBV in the pathogenesis of MS and potentially MOGAD, suggesting its role in the reactivation of HERV-W.

The important biological roles of Syncytin-1 of human endogenous retrovirus W (HERV-W) and Syncytin-2 of HERV-FRD in the human placenta development.

Human endogenous retroviruses (HERVs) entered the germ line by retroviral infection from a distant ancestor over 30million years ago and constitute 8% of the human genome. The majorities of HERVs are non-protein coding and lack function because of the accumulation of mutations, insertions, deletions, and/or truncations. However, a small number of HERV genes carried ORFs with beneficial functions for the host. In this review, we summarize the structural and important biological roles of two HERV gene products termed Syncytin-1 and Syncytin-2 in human placenta development.Indeed, two retroviral gene products that have important roles in mammalian development, Syncytin-1 (HERV-W) and Syncytin-2 (HERV-FRD), are prime examples encoded by env genes and expressed in the placental trophoblasts. Several pivotal studies revealed that Syncytins are fundamental genes implicated in regulating trophoblast fusion and placenta morphogenesis. Interestingly, it has been suggested that syncytins may also be implicated in non-fusogenic activities leading to apoptosis, proliferation, and immunosuppressive activities.

Increased Presence of Antibodies against Type I Interferons and Human Endogenous Retrovirus W in Intensive Care Unit COVID-19 Patients.

ABSTRACTIn this work, we observed an increased presence of antibodies (Abs) against type I interferon (IFN-I) in coronavirus disease 2019 (COVID-19) patients admitted to the intensive care unit (ICU) compared to non-ICU COVID-19 patients and healthy control (HC) subjects. Human endogenous retrovirus W (HERV-W) can reactivate after viral infection; therefore, we also investigated the presence of antibodies against HERV-W envelope (HERV-W-env)-derived epitopes. A total of 113 subjects (41 female and 72 male subjects) were analyzed. A significant difference in autoantibodies against IFN-α, IFN-ω, and HERV-W was observed between HCs and ICU patients; indeed, the latter have higher levels of autoantibodies against IFN-α, IFN-ω, and HERV-W than subjects with mild COVID-19 and HCs. Neutralizing anti-IFN-I autoantibodies may affect the ability of IFN-I to bind to the type I interferon receptor (IFNAR), blocking the activation of the antiviral response.IMPORTANCE In this work, we report the increased presence of IFN autoantibodies in correlation with HERV-W-env autoantibodies in ICU COVID-19 patients. The novelty of the results is in the association of these IFN autoantibodies with autoantibodies against HERV-W-env, a protein recently discovered to be overexpressed in lymphocytes of COVID-19 patients and correlated with severe disease and pneumonia. Type I IFNs are part of a complex cross-regulatory network; however, in a small percentage of cases, the increase in autoantibodies against these proteins may lead to damage to the host instead of protection against infectious diseases.

Autoantibodies against Proinsulin, Human Endogenous Retrovirus W (HERV-W) and Mycobacterium avium Subspecies Paratuberculosis (MAP) Slowly Decrease Years after T1DM Diagnosis

Previous studies have highlighted the potential role of Mycobacterium avium subspecies paratuberculosis (MAP) and human endogenous retrovirus W (HERV-W) in the pathogenesis of type 1 diabetes (T1DM) among Sardinian subjects. To better understand how antibody responses evolve during disease progression, a serological evaluation of IgG antibodies was performed in Sardinian children with T1DM collected at different time-points following the onset of the disease. It is known that anti-PI and anti-insulin (IAA) autoantibodies are the first to appear before the clinical onset of T1DM. In order to investigate the humoral responses, 69 children with T1DM were enrolled in the study, including 25 with new onset, 25 with T1DM at 1–5 years since diagnosis and 19 with T1DM at 6–12 years since diagnosis. Serum samples were tested for the presence of antibodies (Abs) against PI46–61, three MAP epitopes (including MAP 2404c, which has a homologous sequence with PI) and two HERV-W-derived epitopes via indirect enzyme-linked immunosorbent assay (ELISA). The data obtained from the analysis showed significantly higher IgG responses against all peptides detected in the new onset group compared to longer suffering (1–5 and 6–12 years) T1DM patients, also showing a robust correlation between the proinsulin autoantibody and anti-MAP/HERV antibodies, characterized by a progressive decline the first year after onset. Taken together, these findings support the hypothesis that MAP and HERV could act as risk factors for T1DM, suggesting that they may serve as potential biomarkers of disease progression in early-stage T1DM.

Cumulative Roles for Epstein-Barr Virus, Human Endogenous Retroviruses, and Human Herpes Virus-6 in Driving an Inflammatory Cascade Underlying MS Pathogenesis.

Roles for viral infections and aberrant immune responses in driving localized neuroinflammation and neurodegeneration in multiple sclerosis (MS) are the focus of intense research. Epstein-Barr virus (EBV), as a persistent and frequently reactivating virus with major immunogenic influences and a near 100% epidemiological association with MS, is considered to play a leading role in MS pathogenesis, triggering localized inflammation near or within the central nervous system (CNS). This triggering may occur directly via viral products (RNA and protein) and/or indirectly via antigenic mimicry involving B-cells, T-cells and cytokine-activated astrocytes and microglia cells damaging the myelin sheath of neurons. The genetic MS-risk factor HLA-DR2b (DRB1*1501β, DRA1*0101α) may contribute to aberrant EBV antigen-presentation and anti-EBV reactivity but also to mimicry-induced autoimmune responses characteristic of MS. A central role is proposed for inflammatory EBER1, EBV-miRNA and LMP1 containing exosomes secreted by viable reactivating EBV+ B-cells and repetitive release of EBNA1-DNA complexes from apoptotic EBV+ B-cells, forming reactive immune complexes with EBNA1-IgG and complement. This may be accompanied by cytokine- or EBV-induced expression of human endogenous retrovirus-W/-K (HERV-W/-K) elements and possibly by activation of human herpesvirus-6A (HHV-6A) in early-stage CNS lesions, each contributing to an inflammatory cascade causing the relapsing-remitting neuro-inflammatory and/or progressive features characteristic of MS. Elimination of EBV-carrying B-cells by antibody- and EBV-specific T-cell therapy may hold the promise of reducing EBV activity in the CNS, thereby limiting CNS inflammation, MS symptoms and possibly reversing disease. Other approaches targeting HHV-6 and HERV-W and limiting inflammatory kinase-signaling to treat MS are also being tested with promising results. This article presents an overview of the evidence that EBV, HHV-6, and HERV-W may have a pathogenic role in initiating and promoting MS and possible approaches to mitigate development of the disease.

Increased copy number of syncytin-1 in the trophectoderm is associated with implantation of the blastocyst.

BackgroundA key step in embryo implantation is the adhesion to and invasion of the endometrium by the blastocyst trophectoderm. The envelope proteins of HERV-W and -FRD (human endogenous retrovirus-W and -FRD), syncytin-1 and syncytin-2, are mainly distributed in the placenta, and play important roles in the development of the placenta. The placenta originates from the trophectoderm of the blastocyst. It is unclear whether the envelope proteins of HERV-W and -FRD have an effect on the development of the trophectoderm and whether they have any association with the implantation of the blastocyst.MethodsThe whole-genome amplification products of the human blastocyst trophectoderm were used to measure the copy number of syncytin-1 and syncytin-2 using real time qPCR. In addition, clinical data associated with the outcome of pregnancies was collected, and included age, body mass index (BMI), basic follicle stimulating hormone(bFSH), rate of primary infertility and oligo-astheno-teratospermia, the thickness of the endometrium on the day of endometrial transformation, the levels of estrogen and progestin on the transfer day, the days and the morphological scores of the blastocysts. The expression of mRNA and the copy numbers of syncytin-1 and syncytin-2 in H1 stem cells, and in differentiated H1 cells, induced by BMP4, were measured using real time qPCR.ResultsThe relative copy number of syncytin-1 in the pregnant group (median: 424%, quartile: 232%–463%, p < 0.05) was significantly higher than in the non-pregnant group (median: 100%, quartile: 81%–163%). There was a correlation (rs = 0.681, p < 0.001) between the copy number of syncytin-1 and blastocyst implantation after embryo transfer. As the stem cells differentiated, the expression of NANOG mRNA decreased, and the expression of caudal type homeobox 2(CDX2) and β-human chorionic gonadotropin (β-hCG) mRNAs increased. Compared to the undifferentiated cells, the relative expression of the syncytin-1 mRNA was 1.63 (quartile: 0.59–6.37, p > 0.05), 3.36 (quartile: 0.85–14.80, p > 0.05), 10.85 (quartile: 3.39–24.46, p < 0.05) and 67.81 (quartile: 54.07–85.48, p < 0.05) on day 1, 3, 5 and 7, respectively, after the differentiation. The relative expression of syncytin-2 was 5.34 (quartile: 4.50–10.30), 7.90 (quartile: 2.46–14.01), 57.44 (quartile: 38.35–103.87) and 344.76 (quartile: 267.72–440.10) on day 1, 3, 5 and 7, respectively, after the differentiation (p < 0.05). The copy number of syncytin-1 increased significantly during differentiation.ConclusionPreceding the transfer of frozen embryos, the increased copy number of syncytin-1 in the blastocyst trophectoderm was associated with good outcomes of pregnancies.

Syncytin-1/HERV-W envelope is an early activation marker of leukocytes and is upregulated in multiple sclerosis patients.

Syncytin-1 is the envelope protein of the human endogenous retrovirus W (HERV-W). It has been related to multiple sclerosis (MS) but its role in cellular immunity and its pathogenic mechanism in the autoimmune context are not fully understood. We analyzed syncytin-1 levels in peripheral blood mononuclear cells (PBMC) subsets from healthy donors, MS patients in relapse or remission, and patients with acute infections by flow cytometry. PBMC cultures were also prepared to analyze protein expression kinetics. MS patients had higher levels of syncytin-1 levels than controls. We found that syncytin-1 is elevated in monocytes during MS relapses and infections. Cells expressing syncytin-1, including monocytes, T and B lymphocytes, and NKs presented mainly an activated phenotype and, upon stimulation with LPS, its levels increased rapidly on antigen-presenting cells. Syncytin-1 ligation promoted the activation of monocytes, as demonstrated by the upregulation of CD80 and the nonclassical subset CD14low CD16+ . Our results suggest an important role for syncytin-1 in the activation of leukocytes. Given that the expression of syncytin-1 is upregulated in MS patients, this protein might be contributing to the autoimmune cascade in the disease.

Differential Expression of HERV-W in Peripheral Blood in Multiple Sclerosis and Healthy Patients in Two Different Ethnic Groups.

Overexpression of the Human endogenous retrovirus W (HERV-W) group of inherited retroviruses has been consistently linked with Multiple Sclerosis (MS). However most of the studies on this link have focused on European genetic groups with a very high risk of MS and it is not clear that this relationship holds for all ethnic groups. This study examined via qPCR the RNA expression in peripheral blood of HERV-W (the multiple sclerosis associated retrovirus variant MSRV) of MS patients and healthy controls from two ethnic groups with very different risk rates of MS. Population one was derived from the UK with a Northern European genetic background and an MS risk rate of 108/100,000, population two was derived from the republic of Tatarstan, Russian Federation, with a mixed Russian (Eastern European) and Tartar (Turkic or Volga/Urals) population with an MS risk rate of 21-31/100,000. The Russian population displayed a significantly higher basal level of expression of MSRV in both healthy and MS individuals when compared to the British control population with a trend in the Russian population towards higher expression levels in MS patients than healthy patients.

Cutaneous T-Cell Lymphoma (CTCL) Cell Line-Derived Extracellular Vesicles Contain HERV-W-Encoded Fusogenic Syncytin-1

Cutaneous T-Cell Lymphoma (CTCL) Cell Line-Derived Extracellular Vesicles Contain HERV-W-Encoded Fusogenic Syncytin-1

The role of Epstein-Barr virus in multiple sclerosis: from molecular pathophysiology to in vivo imaging.

Multiple sclerosis (MS) is a disease of the central nervous system characterized by inflammation, demyelination, and neuronal damage. Environmental and genetic factors are associated with the risk of developing MS, but the exact cause still remains unidentified. Epstein-Barr virus (EBV), vitamin D, and smoking are among the most well-established environmental risk factors in MS. Infectious mononucleosis, which is caused by delayed primary EBV infection, increases the risk of developing MS. EBV may also contribute to MS pathogenesis indirectly by activating silent human endogenous retrovirus-W. The emerging B-cell depleting therapies, particularly anti-CD20 agents such as rituximab, ocrelizumab, as well as the fully human ofatumumab, have shown promising clinical and magnetic resonance imaging benefit. One potential effect of these therapies is the depletion of memory B-cells, the primary reservoir site where EBV latency occurs. In addition, EBV potentially interacts with both genetic and other environmental factors to increase susceptibility and disease severity of MS. This review examines the role of EBV in MS pathophysiology and summarizes the recent clinical and radiological findings, with a focus on B-cells and in vivo imaging. Addressing the potential link between EBV and MS allows the better understanding of MS pathogenesis and helps to identify additional disease biomarkers that may be responsive to B-cell depleting intervention.

Effects of metal-rich particulate matter exposure on exogenous and endogenous viral sequence methylation in healthy steel-workers

BackgroundInhaled particles have been shown to produce systemic changes in DNA methylation. Global hypomethylation has been associated to viral sequence reactivation, possibly linked to the activation of pro-inflammatory pathways occurring after exposure. This observation provides a rationale to investigate viral sequence (both exogenous and endogenous) methylation in association to metal-rich particulate matter exposure. To verify this hypothesis, we chose the Wp promoter of the Epstein-Barr Virus (EBV-Wp) and the promoter of the human-endogenous-retrovirus w (HERV-w), respectively as a paradigm of an exogenous and an endogenous retroviral sequence, to be investigated by bisulfite PCR Pyrosequencing. We enrolled 63 male workers in an electric furnace steel plant, exposed to high level of metal-rich particulate matter. ResultsComparing samples obtained in the first day of a work week (time 0-baseline, after 2 days off work) and the samples obtained after 3 days of work (time 1-post exposure), the mean methylation of EBV-Wp was significantly higher at baseline compared to post-exposure (meanbaseline = 56.7%5mC; meanpost-exposure = 47.9%5mC; p-value = 0.009), whereas the mean methylation of HERV-w did not significantly differ. Individual exposure to inhalable particles and metals was estimated based on measures in all working areas and time spent by the study subjects in each area. In a regression model adjusted for age, body mass index and smoking, PM and metal components had a positive association with EBV-Wp methylation (i.e. PM10: β = 5.99, p-value < 0.038; nickel: β = 17.82, p-value = 0.02; arsenic: β = 13.59, p-value < 0.015). ConclusionsThe difference observed comparing baseline and post-exposure samples may be suggestive of a rapid change in EBV methylation induced by air particles, while correlation between EBV methylation and PM/metal exposure may represent a more stable adaptive mechanism. Future studies investigating a larger panel of viral sequences could better elucidate possible mechanisms and their role in pro-inflammatory pathways leading to systemic health effects.

A peptide nucleic acid (PNA)-mediated polymerase chain reaction clamping allows the selective inhibition of the ERVWE1 gene amplification

A new peptide nucleic acid (PNA) mediated QPCR technique for the detection and quantification of the Multiple Sclerosis-Associated Retrovirus (MSRV) belonging to the human endogenous retrovirus-W (HERV-W) family has been developed. The assay utilizes a PNA probe which is fully complementary to the ERVWE1 sequence, another member of the HERV-W family which is closely related to MSRV. Due to its excellent affinity to a completely matched template, PNA probe selectively blocks the amplification of ERVWE1 thus allowing the specific and exclusive detection and quantification of the MSRV as PNA does not interfere with the amplification of MSRV. Using this newly developed method we found that MSRV is predominantly expressed over ERWVE1 in astrocyte-derived U-87 MG cell line but not in human umbilical vein endothelial cells or human placental cells.

Expression of Human Endogenous Retrovirus-W Including Syncytin-1 in Cutaneous T-Cell Lymphoma

The pathomechanism of mycosis fungoides (MF), the most common type of primary cutaneous T-cell lymphomas (CTCLs) and a malignancy of non-recirculating, skin-resident T-cells, is unknown albeit underlying viral infections have been sought for. Human endogenous retroviruses (HERVs) are ancient retroviral sequences in the human genome and their transcription is often deregulated in cancers. We explored the transcriptional activity of HERV sequences in a total of 34 samples comprising MF and psoriasis skin lesions, as well as corresponding non-malignant skin using a retrovirus-specific microarray and quantitative RT-PCR. To identify active HERV-W loci, we cloned the HERV-W specific RT-PCR products, sequenced the cDNA clones and assigned the sequences to HERV-W loci. Finally, we used immunohistochemistry on MF patient and non-malignant inflammatory skin samples to confirm specific HERV-encoded protein expression. Firstly, a distinct, skin-specific transcription profile consisting of five constitutively active HERV groups was established. Although individual variability was common, HERV-W showed significantly increased transcription in MF lesions compared to clinically intact skin from the same patient. Predominantly transcribed HERV-W loci were found to be located in chromosomes 6q21 and 7q21.2, chromosomal regions typically altered in CTCL. Surprisingly, we also found the expression of 7q21.2/ERVWE1-encoded Syncytin-1 (Env) protein in MF biopsies and expression of Syncytin-1 was seen in malignant lymphocytes, especially in the epidermotropic ones, in 15 of 30 cases studied. Most importantly, no Syncytin-1 expression was detected in inflammatory dermatosis (Lichen ruber planus) with skin-homing, non-malignant T lymphocytes. The expression of ERVWE1 mRNA was further confirmed in 3/7 MF lesions analyzed. Our observations strengthen the association between activated HERVs and cancer. The study offers a new perspective into the pathogenesis of CTCL since we demonstrate that differences in HERV-W transcription levels between lesional MF and non-malignant skin are significant, and that ERVWE1-encoded Syncytin-1 is expressed in MF lymphoma cells.

Env Gene Expression of Human Endogenous Retrovirus-K and Human Endogenous Retrovirus-W in Childhood Acute Leukemia Cells

Introduction: The etiopathogenesis of childhood leukemia is not fully understood. It is suggested that endogenous viral sequences may play a role in leukemogenesis. Human endogenous retroviruses (HERVs) constitute about 8% of the human genome. Most HERVs are dysfunctional because of numerous mutations and deletions. Some HERVs, however, contain sequences capable of transcription. In patients with leukemia, the presence of antibodies against HERV-K has been identified, which could suggest increased expression of HERV-K in leukemic cells. To elucidate the role of endogenous retroviruses in leukemogenesis, studies were undertaken to assess env gene expression of HERV-K and HERV-W in childhood acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML). Results: This study was performed in 170 children with ALL, 38 subjects with AML, and 30 healthy subjects. Expression of the env gene of HERV-K and HERV-W and the control gene ACTB was studied by real-time PCR using specific oligonucleotide primers and SYBR Green marker. Env gene expression was assessed on the basis of the absolute threshold-C_t, as well as normalized against ACTB expression and double normalized expression relative to ACTB and reference cells – normal peripheral blood lymphocytes (PBL). Env gene expression of HERV-K normalized against ACTB, as well as double normalized expression relative to ACTB and normal PBL, was significantly higher only in AML. There were no statistically significant differences in env gene expression of HERV-W normalized to ACTB in ALL and AML as compared to normal PBL. Conclusion: High normalized expression of the env gene of HERV-K in AML strongly suggests a possible contribution of this gene in the pathogenesis of AML.

The DNA Copy Number of Human Endogenous Retrovirus-W (MSRV-Type) Is Increased in Multiple Sclerosis Patients and Is Influenced by Gender and Disease Severity

BackgroundMultiple Sclerosis is an autoimmune disease more prevalent in women than in men. Multiple Sclerosis Associated Retrovirus element (MSRV) is a member of type-W endogenous retrovirus family (HERV-W), known to be associated to MS. Most HERVs are unable to replicate but MSRV expression associated with reverse-transcriptase activity in MS would explain reported DNA copy number increase in MS patients. A potential link between HERV-W copies on chromosome X and gender differential prevalence has been suggested. The present study addresses MSRV-type DNA load in relation with the gender differences and clinical status in MS and healthy controls.Results178 MS patients (62.9% women) and 124 controls (56.5% women) were included. MSRV env load (copies/pg of DNA) was analyzed by real time qPCR with specific primers and probe for its env gene, in DNA from peripheral blood mononuclear cells (PBMCs). MSRV load was more elevated in MS patients than in controls (p = 4.15e-7). MS women presented higher MSRV load than control women (p = 0.009) and MS men also had higher load than control men (p = 2.77e-6). Besides, women had higher levels than men, both among patients (p = 0.007) and controls (p = 1.24e-6). Concordantly, EDSS and MSSS scores were higher among female patients with an elevated MSRV load (p = 0.03 and p = 0.04, respectively).ConclusionsMSRV increases its copy number in PBMC of MS patients and particularly in women with high clinical scores. This may explain causes underlying the higher prevalence of MS in women. The association with the clinical severity calls for further investigations on MSRV load in PBMCs as a biomarker for MS.

Neuroinflammation and Endoplasmic Reticulum Stress Are Coregulated by Crocin To Prevent Demyelination and Neurodegeneration

Endoplasmic reticulum (ER) stress is a homeostatic mechanism, which is used by cells to adapt to intercellular and intracellular changes. Moreover, ER stress is closely linked to inflammatory pathways. We hypothesized that ER stress is an integral component of neuroinflammation and contributes to the development of neurological diseases. In autopsied brain specimens from multiple sclerosis (MS) and non-MS patients, XBP-1 spliced variant (XBP-1/s) was increased in MS brains (p < 0.05) and was correlated with the expression of the human endogenous retrovirus-W envelope transcript, which encodes the glycoprotein, Syncytin-1 (p < 0.05). In primary human fetal astrocytes transfected with a Syncytin-1-expressing plasmid, XBP-1/s, BiP, and NOS2 were induced, which was suppressed by crocin treatment (p < 0.05). Crocin also protected oligodendrocytes exposed to cytotoxic supernatants derived from Syncytin-1-expressing astrocytes (p < 0.05) and NO-mediated oligodendrocytotoxicity (p < 0.05). During experimental autoimmune encephalomyelitis (EAE), the transcript levels of the ER stress genes XBP-1/s, BiP, PERK, and CHOP were increased in diseased spinal cords compared with healthy littermates (p < 0.05), although CHOP expression was not involved in the EAE disease phenotype. Daily treatment with crocin starting on day 7 post-EAE induction suppressed ER stress and inflammatory gene expression in spinal cords (p < 0.05), which was accompanied by preserved myelination and axonal density, together with reduced T cell infiltration and macrophage activation. EAE-associated neurobehavioral deficits were also ameliorated by crocin treatment (p < 0.05). These findings underscored the convergent roles of pathogenic ER stress and immune pathways in neuroinflammatory disease and point to potential therapeutic applications for crocin.

Fusogenic membrane glycoproteins induce syncytia formation and death in vitro and in vivo: a potential therapy agent for lung cancer

Fusogenic membrane glycoproteins (FMGs) are viral envelope proteins, which bind surface receptors and induce fusion of the cell membrane. An FMG-transfected cell will fuse with neighbor cells, thus forming syncytia that die within 5 days. In this report, plasmids encoding for FMGs from Human Endogenous Retrovirus-W (HERV-W) was compared with Gibbon Ape Leukemia Virus (GALV) and feline endogenous virus RD-114 (RD). These plasmids were transfected in human non-small-cell lung cancer (NSCLC) cells in vitro or directly injected into tumors in mice. All FMGs induced the formation of syncytia containing around 50 cells. HERV-W or GALV FMGs decreased up to 80% of cell viability in vitro and inhibited tumor growth in vivo (60-70% reduction). In contrast, RD FMG was not efficient. Apoptosis played a role in the death of the syncytia, but addition of the caspase inhibitor Z-VAD-fmk had no effect, suggesting that apoptosis is not the only mechanism responsible for FMG-induced cell death. Altogether, our results demonstrate that even at very low transfection efficiency, the antitumor activity of HERV-W FMG is as effective as that of GALV in vitro and in vivo for the treatment of human lung tumors.