Pathogenesis Of Progressive Multifocal Leukoencephalopathy Research Articles

Exploring JC Polyomavirus Sequences and Human Gene Expression in Brain Tissue of Patients With Progressive Multifocal Leukoencephalopathy.

Progressive multifocal leukoencephalopathy (PML) is a rare neurological condition associated with reactivation of dormant JC polyomavirus (JCPyV). In this study, we characterized gene expression and JCPyV rearrangements in PML brain tissue. Infection of white matter astrocytes and oligodendrocytes as well as occasional brain cortex neurons was shown. PML brain harbored exclusively rearranged JCPyV variants. Viral transcripts covered the whole genome on both strands. Strong differential expression of human genes associated with neuroinflammation, blood-brain barrier permeability, and neurodegenerative diseases was shown. Pathway analysis revealed wide immune activation in PML brain. The study provides novel insights into the pathogenesis of PML.

Progressive multifocal leukoencephalopathy in HIV-positive individuals

The article discusses the historical aspect and modern ideas about the etiology and pathogenesis of progressive multifocal leukoencephalopathy in patients with HIV infection. An analysis and synthesis of literature data on the clinical presentation of this pathology was carried out. The possibilities and limitations of laboratory and instrumental diagnostic methods, including neuroimaging methods, are discussed in detail. The pathomorphological signs of the disease in HIV-positive individuals are covered.

Progressive multifocal leukoencephalopathy (PML) treated with pembrolizumab in a patient with mosaic STAT3 gain-of-function mutation

Progressive multifocal leukoencephalopathy (PML) is a rare and often fatal disease of the central nervous system caused by JC virus. It occurs exclusively in immunocompromised hosts and is strongly associated with HIV infection and iatrogenic immunosuppression. Monogenic defects underlying the pathogenesis and reactivation of JC virus are not well understood, although some reports of primary immunodeficiencies (including four cases of STAT1 gain-of-function) have been previously described.A 77 year old male with history of prostate cancer (in remission; treated with radiation and hormonal therapy >10 years ago) presented with dysarthria, ataxia, left-sided weakness, diagnosed with CSF and biopsy-confirmed PML. He underwent an extensive workup upon which no other chronic infectious or oncologic processes were identified. He has never received any form of immunomodulation (including chemotherapy) in the past. Workup revealed low CD4 (347/mm3) and CD8 (282/mm3) T cell counts with normal proportions of naive vs. memory populations. Mitogen stimulation demonstrated poor CD8T cell proliferation. Targeted sequencing revealed a heterozygous mosaic mutation in the DNA-binding domain of STAT3 (c.1229 A > G p.H410R, 14% in 96 reads). This variant had been previously identified in two individuals with large granular lymphocyte (LGL) leukemia and validated as a gain-of-function via downstream signaling assays.Our patient demonstrated a favorable response to PD-1 blockade with pembrolizumab (2 mg/kg) and was discharged to a rehabilitation facility. His MRI brain showed no further progression of cerebellar white matter lesions following three doses of pembrolizumab.To our knowledge, this is the first case to implicate that STAT3 gain-of-function may confer a predisposition to JC virus reactivation and/or control in the pathogenesis of PML. Furthermore, we propose that this patient’s response to pembrolizumab may be partially attributed to STAT3-mediated regulation of the PD-1/PD-L1 axis. Further studies are currently underway to characterize this patient’s mosaic variant in flow cytometry-sorted subsets (including CD8T cells). Additional studies may include measurement of PD-1/PD-L1 expression and basal vs. induced STAT3 phosphorylation in sorted cell populations.

JC Polyomavirus Modifies the Expression of Human microRNAs in Progressive Multifocal Leukoencephalopathy Brain.

Progressive multifocal leukoencephalopathy (PML) is a severe neurological condition caused by reactivation of JC polyomavirus (JCPyV) in immunosuppression. Asymptomatic JCPyV persists in peripheral tissues. Upon reactivation, neurotropic rearrangements may emerge, and the virus gains access to the brain. To assess the mechanisms of PML pathogenesis, brain tissue material from PML patients was collected for small RNA sequencing. Upregulation of 8 microRNAs (miRNAs) in PML brain was validated using quantitative microRNA polymerase chain reaction (PCR). Bioinformatics tools were utilized to identify major associations of the upregulated miRNAs: neuroinflammation and blood-brain barrier disruption. The results indicate involvement of human miRNA regulation in PML pathogenesis.

A human-derived 3D brain organoid model to study JC virus infection.

Progressive multifocal leukoencephalopathy (PML) is a frequent neurological complication in immunosuppressed patients. PML is caused by the JC virus (JCV), a neurotropic DNA polyomavirus that infects oligodendrocytes and astrocytes, causing inflammation and demyelination which lead to neurological dysfunction. The pathogenesis of PML is poorly understood due to the lack of in vitro or animal models to study mechanisms of disease as the virus most efficiently infects only human cells. We developed a human-derived brain organotypic system (also called brain organoid) to model JCV infection. The model was developed by using human-induced pluripotent stem cells (iPSC) and culturing them in 3D to generate an organotypic model containing neurons, astrocytes, and oligodendrocytes which recapitulates aspects of the environment of the human brain. We infected the brain organoids with the JCV MAD4 strain or cerebrospinal fluid of a patient with PML. The organoids were assessed for evidence of infection by qPCR, immunofluorescence, and electron microscopy at 1, 2, and 3 weeks post-exposure. JCV infection in both JCV MAD4 strain and PML CSF-exposed brain organoids was confirmed by immunocytochemical studies demonstrating viral antigens and electron microscopy showing virion particles in the nuclear compartment of oligodendrocytes and astrocytes. No evidence of neuronal infection was visualized. Infection was also demonstrated by JCV qPCR in the virus-exposed organoids and their media. In conclusion, the brain organoid model of JCV infection establishes a human model suitable for studying the mechanisms of JCV infection and pathogenesis of PML and may facilitate the exploration of therapeutic approaches.

Hope for progressive multifocal leukoencephalopathy

Progressive multifocal leukoencephalopathy is a rare but important brain disease caused by JC virus. This polyomavirus typically causes an asymptomatic infection in healthy people. In a few individuals with chronic cellular immunodeficiency, JC virus evolves to become neurotropic, infecting and killing oligodendrocytes to cause a subacute progressive demyelinating disease that generally is fatal within 6 months from symptom onset. 1 Major EO Yousry TA Clifford DB Pathogenesis of progressive multifocal leukoencephalopathy and risks associated with treatments for multiple sclerosis: a decade of lessons learned. Lancet Neurol. 2018; 17: 467-480 Summary Full Text Full Text PDF PubMed Scopus (104) Google Scholar BK virus-specific T cells for immunotherapy of progressive multifocal leukoencephalopathy: an open-label, single-cohort pilot studyWe showed that generation of polyomavirus-specific T cells from healthy related donors is feasible, and these cells can be safely used as an infusion for adoptive immunotherapy of progressive multifocal leukoencephalopathy. Although not powered to assess efficacy, our data provide additional support for this strategy as a potential life-saving therapy for some patients. Full-Text PDF

Understanding polyomavirus CNS disease - a perspective from mouse models.

JC polyomavirus (JCPyV), a ubiquitous human pathogen, causes several devastating brain diseases in immune-compromised individuals. The most notable of these JCPyV-associated CNS diseases is the frequently fatal demyelinating brain disease progressive multifocal leukoencephalopathy (PML). PML, an AIDS-defining disease in the pre-cART epoch, has emerged as a life-threatening complication in patients receiving immunomodulatory agents for autoimmune and inflammatory disorders and treatment for certain hematological malignancies. Among the rapidly expanding list of PML-associated biologics, natalizumab (Tysabri®) has the highest incidence and is an ominous sequela for multiple sclerosis (MS) patients who otherwise benefit from dramatic reductions in relapses using this immunomodulatory agent. Drug withdrawal, the only therapeutic option for PML, is often complicated by a high-mortality cerebral inflammatory reaction. No anti-JCPyV agents are available. Lack of a tractable animal model of polyomavirus-induced central nervous system (CNS) disease is an acknowledged bottleneck to elucidating PML pathogenesis, immunological mechanisms that control JCPyV, in vivo evaluation of agents that inhibit polyomavirus replication in tissue culture, and uncovering early events that presage JCPyV-associated neuropathology. The natural virus-host mouse polyomavirus (MuPyV) model has recently been developed to explore mechanisms of polyomavirus-associated CNS disease. In this review, we will cover the benefits of using the MuPyV model to answer fundamental questions about innate and adaptive immune control of JCPyV, the impact of immunomodulation on JCPyV pathogenesis, and how this MuPyV CNS infection model will help improve criteria for identifying patients at risk for JCPyV-associated CNS diseases before the development of irreversible lesions.

JC Polyomavirus Infection Reveals Delayed Progression of the Infectious Cycle in Normal Human Astrocytes.

JC polyomavirus (JCPyV) infects 50 to 80% of the population and is the causative agent of a fatal demyelinating disease of the central nervous system (CNS). JCPyV presents initially as a persistent infection in the kidneys of healthy people, but during immunosuppression, the virus can reactivate and cause progressive multifocal leukoencephalopathy (PML). Within the CNS, JCPyV predominately targets two cell types, oligodendrocytes and astrocytes. Until recently, the role of astrocytes has been masked by the pathology in the myelin-producing oligodendrocytes, which are lytically destroyed by the virus. To better understand how astrocytes are impacted during JCPyV infection, the temporal regulation and infectious cycle of JCPyV were analyzed in primary normal human astrocytes (NHAs). Previous research to define the molecular mechanisms underlying JCPyV infection has mostly relied on the use of cell culture models, such as SVG-A cells (SVGAs), an immortalized, mixed population of glial cells transformed with simian virus 40 (SV40) T antigen. However, SVGAs present several limitations due to their immortalized characteristics, and NHAs represent an innovative approach to study JCPyV infection in vitro Using infectivity assays, quantitative PCR, and immunofluorescence assay approaches, we have further characterized JCPyV infectivity in NHAs. The JCPyV infectious cycle is significantly delayed in NHAs, and the expression of SV40 T antigen alters the cellular environment, which impacts viral infection in immortalized cells. This research establishes a foundation for the use of primary NHAs in future studies and will help unravel the role of astrocytes in PML pathogenesis.IMPORTANCE Animal models are crucial in advancing biomedical research and defining the pathogenesis of human disease. Unfortunately, not all diseases can be easily modeled in a nonhuman host or such models are cost prohibitive to generate, including models for the human-specific virus JC polyomavirus (JCPyV). JCPyV infects most of the population but can cause a rare, fatal disease, progressive multifocal leukoencephalopathy (PML). There have been considerable advancements in understanding the molecular mechanisms of JCPyV infection, but this has mostly been limited to immortalized cell culture models. In contrast, PML pathogenesis research has been greatly hindered because of the lack of an animal model. We have further characterized JCPyV infection in primary human astrocytes to better define the infectious process in a primary cell type. Albeit a cell culture model, primary astrocytes may better recapitulate human disease, are easier to maintain than other primary cells, and are less expensive than using an animal model.

Progressive Multifocal Leukoencephalopathy as a Complication of Disease-modifying Treatment of Multiple Sclerosis

The review provides modern understanding of the pathogenesis of progressive multifocal leukoencephalopathy (PML), a severe and potentially fatal form of multiple-lesion disorder of the brain white matter. Information about the frequency of its development in patients with disease-modifying treatment of multiple sclerosis is analyzed. The algorithms of optimization of PML risks in this category of patients with multiple sclerosis are described in detail. Summarized are the data on most significant PML biomarkers, the search for which is currently under way in many centers across the world. The first case of PML in Russia is briefly described.

High Expression of Polyomavirus-Encoded MicroRNAs in Progressive Multifocal Leukoencephalopathy and BK Polyomavirus-Associated Nephropathy Tissues, and Their Repressive Role in Virus Replication

Background: Replication of JC polyomavirus (JCPyV, JCV) is associated with the pathogenesis of progressive multifocal leukoencephalopathy (PML). The JCPyV genome encodes a microRNA (miRNA) in the region encoding the large T antigen. This JCPyV-encoded miRNA (miR-J1) has been detected in tissue and cerebrospinal fluid samples of patients with PML. However, the localisation of the miRNA has rarely been reported. Methods: We detected viral miRNA by in situ hybridisation in polyomavirus-infected tissues. We measured the miR-J1 copy number with real-time RT PCR. Small RNAs were sequenced by next generation sequencing. Recombinant JCPyV DNA was transfected into cultured cells for functional analysis of the miRNA. Findings: We detected high expression of miR-J1 in the nuclei of JCPyV-infected cells in PML tissue samples by in situ hybridisation. In situ hybridisation also demonstrated the expression of BK polyomavirus (BKPyV, BKV)-encoded miRNA in lesions of BKPyV-associated nephropathy. Higher copy numbers of miR-J1 were detected in PML tissues than non-PML tissues by real-time PCR. Next generation sequencing showed that miR-J1-5p, a mature miRNA of miR-J1, was predominant in the lesions compared with miR-J1-3p, another mature miRNA. Deletion or mutation of miR-J1 in recombinant JCPyV promoted the production of JCPyV-encoded proteins in cells transfected with JCPyV DNA. Interpretation: We have demonstrated nuclear localisation of polyomavirus-encoded miRNA in tissue samples of polyomavirus-associated diseases. Our results suggest that polyomavirus-encoded miRNA may have a repressive role in viral replication in PML tissues. In situ hybridisation for viral miRNA may be a useful diagnostic tool for PML. Funding: AMED, JSPS, and MHLW, Japan. Declaration of Interest: The authors declare that they have no conflict of interest. Ethical Approval: All procedures performed in studies involving human tissues were in accordance with the ethical standards of the Institutional Review Board of the National Institute of Infectious Diseases (Approval No. 595) and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.

Progressive multifocal leukoencephalopathy as a complication of disease-modifying treatment of multiple sclerosis

The review provides modern understanding of the pathogenesis of progressive multifocal leukoencephalopathy (PML), a severe and potentially fatal form of multiple-lesion disorder of the brain white matter. Information about the frequency of its development in patients with disease-modifying treatment of multiple sclerosis is analyzed. The algorithms of optimization of PML risks in this category of patients with multiple sclerosis are described in detail. Summarized are the data on most significant PML biomarkers, the search for which is currently under way in many centers across the world. The first case of PML in Russia is briefly described.

Progress on pathogenesis of progressive multifocal leukoence-phalopathy

Progressive multifocal leukoencephalopathy (PML) is a rare and lethal central nervous demyelinating disease caused by JC polyomavirus (JCV), particularly in patients with impaired immune system. The variation of JCV plays an important role in the pathogenesis of PML, including the recombination of non-coding regulatory region (NCCR), which is closely related to binding sites of transcription factors and affect the level of gene transcription. Nucleotide mutations in VP1 region determine the antigenicity and receptor specificity of JCV, play an important role in cell adsorption, immune-mediation and pathogenicity. In addition, immune cells are also involved in the pathogenesis of PML. T lymphocytes can recognize virus antigens, clear JCV, which are directly related to the prognosis of PML. B lymphocytes can serve as latent sites of JCV, and participate in viral transmission, replication, and coordination of the expression of transcription factors. This paper summarizes the roles of JCV variation and immune cells in pathogenesis of PML.

Progressive multifocal leukoencephalopathy

Progressive multifocal leukoencephalopathy (PML) is adisease of immunosuppressed patients caused by the JC polyomavirus (JCPyV). Due to the elevated risk in patients treated with natalizumab for multiple sclerosis (MS) and also treatment with other biologicals for different indications, the relevance of PML has increased in recent years. This article summarizes the published knowledge on the biology and pathogenesis of PML with a focus on the role of cerebrospinal fluid diagnostics in the work-up for PML and the current PML case definition. Current recommendations regarding risk management are discussed, as are possible therapies and prevention.

Treatment-Related Progressive Multifocal Leukoencephalopathy in Multiple Sclerosis: A Comprehensive Review of Current Evidence and Future Needs.

Progressive multifocal leukoencephalopathy (PML) is a rare opportunistic infection of the central nervous system caused by the John Cunningham virus (JCV) that has been associated with therapeutic immunosuppression in patients with multiple sclerosis (MS). So far, more than 600 cases of PML have been reported in association with natalizumab administration. There have also been confirmed cases of PML in individuals who received fingolimod and dimethyl fumarate without previous natalizumab treatment. The new licensed disease-modifying therapies for MS carry the risk of immunosuppressant and so of JCV reactivation. Various factors have been identified with increased risk of developing PML, including a positive JCV serology, natalizumab administration for>2years, and prior use of immunosuppressive agents. Clinicians can employ such tools for patients' risk stratification, but the incidence of PML among patients receiving natalizumab therapy has not changed. In this review we outline the current state of understanding of PML pathogenesis and patients' risk stratification. The landscape of MS is dramatically changing and knowledge of the side effects of the licensed therapies is imperative to enable optimal decision making.

Single-Molecule Sequencing Revealing the Presence of Distinct JC Polyomavirus Populations in Patients With Progressive Multifocal Leukoencephalopathy.

Progressive multifocal leukoencephalopathy (PML) is a fatal disease caused by reactivation of JC polyomavirus (JCPyV) in immunosuppressed individuals and lytic infection by neurotropic JCPyV in glial cells. The exact content of neurotropic mutations within individual JCPyV strains has not been studied to our knowledge. We exploited the capacity of single-molecule real-time sequencing technology to determine the sequence of complete JCPyV genomes in single reads. The method was used to precisely characterize individual neurotropic JCPyV strains of 3 patients with PML without the bias caused by assembly of short sequence reads. In the cerebrospinal fluid sample of a 73-year-old woman with rapid PML onset, 3 distinct JCPyV populations could be identified. All viral populations were characterized by rearrangements within the noncoding regulatory region (NCCR) and 1 point mutation, S267L in the VP1 gene, suggestive of neurotropic strains. One patient with PML had a single neurotropic strain with rearranged NCCR, and 1 patient had a single strain with small NCCR alterations. We report here, for the first time, full characterization of individual neurotropic JCPyV strains in the cerebrospinal fluid of patients with PML. It remains to be established whether PML pathogenesis is driven by one or several neurotropic strains in an individual.

CD8 T cells mediate polyomavirus-associated CNS demyelination

Abstract JC polyomavirus (JCV), a common member of the virome in healthy humans, can cause the frequently fatal brain demyelinating disease Progressive Multifocal Leukoencephalopathy (PML) in immunocompromised individuals. PML, a pre-HAART AIDS-defining disease, has reemerged and is increasing in incidence in patients receiving immunodulatory therapies for autoimmune and inflammatory disorders. Lack of an animal model has hampered understanding of PML pathogenesis. We have developed a novel mouse model using intracerebral (i.c.) inoculation of mouse polyomavirus (MPyV), which mimics JCV-associated demyelination and shows similar histological features to PML. By one month after MPyV inoculation, C57BL/6 mice develop diffuse subcortical white matter demyelination, predominantly in the corpus callosum. Diffusion tensor magnetic resonance imaging in infected mice reveals severe peri-ventricular edema and a loss of structural integrity predominately in the corpus callosum and caudate. Virus-specific CD8 T cells robustly infiltrate the CNS and are stably maintained after CNS entry. Antibody-mediated depletion of CD4 and CD8 T cells prior to infection abrogates demyelination in the corpus callosum, despite resulting in a 50–100 fold increase in virus levels. Additionally, CD8 T cell-depletion alone was sufficient to cause higher virus levels in the brain. MPyV was controlled in the absence of CD4 T cells; however, MPyV-specific CD8 T cells in CD4 T cell-deficient mice expressed lower levels of CD103 (aE integrin), which binds epithelial E-cadherin. These data demonstrate that CD8 T cells infiltrating the CNS of MPyV-infected mice play a major role in this demyelinating leukoencephalitis.

PROGRESSIVE MULTIFOCAL LEUKOENCEPHALOPATHY ASSOCIATED TO MULTIPLE SCLEROSIS THERAPIES: REVIEW OF THE LITERATURE

Progressive multifocal leukoencephalopathy (PML) is an opportunistic infection associated with the reactivation of the JC virus, causing a severe demyelination within the central nervous system in patients with immunosuppression caused by disease or secondary to use of drugs. Several therapies used in the treatment of MS have reported cases of associated PML, most cases being related to Natalizumab treatment. In this article we review specific MS medication with a reported risk for PML, and also revise PML epidemiology, pathogenesis, treatment and available approaches on therapy in patients at high risk for developing this infection.

Expression of Signaling Molecules in Progressive Multifocal Leukoencephalopathy.

Progressive multifocal leukoencephalopathy (PML) is a debilitating demyelinating disease of the CNS caused by the infection and destruction of glial cells by JC virus (JCV) and is an AIDS-defining disease. Infection with JCV is common and most people acquire antibodies early in life. After initial infection, JCV remains in an asymptomatic persistent state and can be detected by PCR in many tissues including brain. A major question in PML pathogenesis is how the virus reactivates from persistence in HIV-1/AIDS. Our studies with primary cultures of glial cells have implicated transcription factors NF-κB and NFAT4, which bind to a unique site in the JCV noncoding control region and stimulate viral gene expression. Furthermore, these transcription factors are controlled by pathways downstream of proinflammatory cytokines, e.g., TNF-α activates NF-κB and stimulates JCV transcription. We hypothesize that HIV-1/PML initiation may involve reactivation of JCV by cytokine disturbances in the brain such as occur in HIV-1/AIDS. In this study, the objective was to evaluate HIV-1/PML clinical samples for expression of TNF-α and its receptors and subcellular localization of NF-κB p65 and NFAT4 compared to non-PML controls. We evaluated HIV-1/PML clinical samples and non-PML controls for expression of TNF-α and its receptors and subcellular localization of NF-κB p65 and NFAT4 using Western blot and immunohistochemistry. Consistent with our hypothesis, compared to non-PML controls, HIV-1/PML tissue has high levels of TNF-α and TNFR1 expression and NF-κB and NFAT4 were preferentially localized to the nucleus. The involvement of TNF-α/NF-κB/NFAT4 signaling in JCV regulation that we reported from experiments in cultured human glial cells may be clinically relevant in PML.

2nd International Conference on Progressive Multifocal Leukoencephalopathy (PML) 2015: JCV virology, progressive multifocal leukoencephalopathy pathogenesis, diagnosis and risk stratification, and new approaches to prevention and treatment.

2nd International Conference on Progressive Multifocal Leukoencephalopathy (PML) 2015: JCV virology, progressive multifocal leukoencephalopathy pathogenesis, diagnosis and risk stratification, and new approaches to prevention and treatment.

B cells and progressive multifocal leukoencephalopathy: search for the missing link.

Progressive multifocal leukoencephalopathy (PML) is a deadly demyelinating disease due to JC virus (JCV) replication in the brain. PML classically occurs in patients with severe immunodepression, and cases have recently been linked to therapeutic monoclonal antibodies such as natalizumab and also rituximab, which depletes B cells. B cells appear to play a complex role in the pathogenesis of PML. They may act as a viral reservoir and as a vector for viral dissemination in the central nervous system. Anti-JCV antibody responses appear to have a limited effect on JCV replication in the brain. However, accumulating evidence suggests that B cells may considerably influence T cell responses through their cytokine secretion. This immunomodulatory function of B cells may play an important role in the control of JCV infection and in the pathogenesis of PML, including rituximab-induced PML.