Sonia Villani

Human polyomavirus 6 DNA in the cerebrospinal fluid of an HIV-positive patient with leukoencephalopathy

BACKGROUND Leukoencephalopathies in HAART-treated, HIV-positive patients include progressive multifocal leukoencephalopathy (PML), a result of lytic infection oligodendrocytes by JC polyomavirus (JCV), and another form characterized by the absence of JCV genome in cerebrospinal fluid (CSF). OBJECTIVES To test the potential viral etiology of JCV-negative leukoencephalopathy. STUDY DESIGN CSF was collected from 43 HIV-positive patients with MRI suggestive of leukoencephalopathies. DNA was isolated and real-time PCR assays for neurotropic viruses (Herpes Simplex Viruses 1/2, Varicella Zoster Virus, Epstein Barr Virus, Human Cytomegalovirus, Human Herpesvirus 6, JCV and HIV) were conducted. CSF from 14 non-reactive cases were subjected to random nucleic acid amplification, deep sequencing, and in silico search for viral sequences. RESULTS JCV genome was detected in the CSF of 19/43 PML patients, HIV genome in the CSF of 5 PML patients including 2 JCV negative patients, and no viruses were detected in 22 patients. Human Polyomavirus 6 (HPyV6) DNA was detected by deep sequencing in one JCV-negative leukoencephalopathy CSF sample. CONCLUSIONS HPyV6 DNA was detected in CSF of a case of demyelinating disease. HPyV6 has not been previously reported in CSF or associated with any disease. Demonstrating a causative role will require further studies.

Interaction between Human Polyomavirus BK and Hypoxia inducible factor‐1 alpha

BK polyomavirus (BKV) has a worldwide seroprevalence of approximately 90%. After primary infection, BKV establishes a life‐long latency within the urogenital tract. The severe immunological impairment occurring in renal transplant recipients leads to BKV reactivation, which may result in polyomavirus associated nephropathy (PVAN). While the transplanted kidney is transiently unperfused, Hypoxia Inducible Factors (HIFs) mediate the cellular response to hypoxia. The α‐subunit of HIF isoform 1 (HIF‐1α) may interact with several viruses, but until now, there has been no information regarding the interaction between BKV and HIF‐1α. The aim of this study is to investigate the possible interaction between HIF‐1α and BKV and its potential effect on the pathogenesis of PVAN. Screening of 17 kidney tissue samples revealed that HIF‐1α expression was 13.6‐fold higher in PVAN tissues compared to control tissues. A luminometric assay in co‐transfected African green monkey kidney cells (VERO) demonstrated BKV promoter activation ranging from two to sixfold (P < 0.05) when HIF‐1α was over‐expressed. A Chromatin ImmunoPrecipitation (ChIP) assay showed structural binding between the BKV promoter and HIF‐1α. The amount of BKV DNA increased by threefold in VERO infected cells that were exposed to simulated hypoxia, compared to the cells not subjected to hypoxia. Both ex vivo and in vitro interactions between HIF‐1α and BKV were observed, suggesting that HIF‐1α, stabilized during transplantation, may be able to bind the BKV promoter and enhance BKV replication. Thus, hypoxia should be considered a risk factor for the development of PVAN in kidney transplant recipients. J. Cell. Physiol. 231: 1343–1349, 2016.

A Potential Linkage Between the JC and BK Polyomaviruses and Brain and Urinary Tract Tumors: A Review of the Literature

JC virus (JCV) and BK virus (BKV) belong to the Polyomaviridae family and were the first human polyomaviruses (PyVs) discovered. Both JCV and BKV remain latent in the kidneys and can reactivate in immunocompromised hosts, causing progressive multifocal leukoencephalopathy (PML) and nephropathy, respectively. PyVs induce cell transformation in vitro and in animal models, where they infect non-permissive cells. The molecular mechanisms of tumor formation are based on the large tumor antigen (T Ag) protein, which is able to bind and inactivate pRb and p53, inducing uncontrolled cell cycle progression. Many studies on clinical samples also indicate a positive association between JCV and BKV and human solid tumors; however no direct involvement of PyVs in the development of human cancers has been demonstrated. In this review we focused on the potential association between JCV and BKV with brain and urinary tract tumors, respectively.

Human Polyomaviruses: The Battle of Large and Small Tumor Antigens

About 40 years ago, the large and small tumor antigens (LT-Ag and sT-Ag) of the polyomavirus (PyVs) simian vacuolating virus 40 have been identified and characterized. To date, it is well known that all the discovered human PyVs (HPyVs) encode these 2 multifunctional and tumorigenic proteins, expressed at viral replication early stage. The 2 T-Ags are able to transform cells both in vitro and in vivo and seem to play a distinct role in the pathogenesis of some tumors in humans. In addition, they are involved in viral DNA replication, transcription, and virion assembly. This short review focuses on the structural and functional features of the HPyVs’ LT-Ag and sT-Ag, with special attention to their transforming properties.

Upregulation of integrin expression on monocytes in multiple sclerosis patients treated with natalizumab

Natalizumab is a humanized monoclonal antibody against the α4 subunit of VLA-4 integrin that is used to treat conditions such as multiple sclerosis (MS). Although its effects on lymphocytes have been widely described, little is known about its effects on monocytes. Here we described the effects of natalizumab treatment on peripheral blood monocytes from a small cohort of MS patients in terms of relative frequencies and surface integrin (CD49d and CD18) expression. We showed that natalizumab treatment altered the surface integrin expression on monocyte subsets in the peripheral compartment, suggesting a role for them as mediators of natalizumab effects.

Multiplex array analysis of circulating cytokines and chemokines in natalizumab-treated patients with multiple sclerosis

Natalizumab greatly reduces inflammatory relapses in multiple sclerosis (MS) by blocking the integrin-mediated leukocyte traffic to the brain, but less is known about its effects on the systemic immunity. We measured 48 cytokines/chemokines in sera from 19 natalizumab-treated MS patients. Serum concentrations of both anti-(IL-10, IL1ra) and pro-inflammatory (IL7, IL16) molecules decreased after 21-month treatment, without associations to unbalanced Th2/Th1cytokine ratios, clinical responses, and blood/urine replication of polyomavirus JC (JCPyV). No patient developed the JCPyV-related progressive multifocal leukoencephalopathy (PML), the major risk factor of natalizumab therapy. Our data suggest that natalizumab has marginal impact on the systemic immunity.

Characterization of an in vitro model to study the role of human Polyomavirus BK in prostate cancer

Prostate cancer (PCa) is one of the most common male neoplasm in the western world, being the most commonly diagnosed non-skin cancer and the second leading cause of cancer death. Various potential risk factors exist for the initial triggering events, including exposure to infectious agents, such as the human Polyomavirus BK (BKV). BKV is a good candidate as risk factor of PCa because it naturally infects the human reno-urinary tract, it establishes latency, and encodes oncoproteins that interfere with tumor suppressors pathways, thus altering the normal progression of cell cycle. Previous studies suggested a potential association between BKV and PCa, revealing that the prevalence of BKV was significantly higher in cancer than in control tissues, with a significant association between viral expression and cancer. However, this hypothesis is controversial because BKV is not restricted to tumor tissues but also infects healthy individuals in a high percentage. Moreover, an in vitro model of BKV infection in prostate cells is not available to understand the role for BKV in pathogenesis of PCa. Our aims were to determine whether BKV a) could infect normal epithelial prostate cells, b) affects cell phenotype and c) affects the phenotype of human prostate tumor cell line PC3. For this purpose normal epithelial prostate cell line RWPE-1 and prostate cancer cells PC3 were infected with BKV for 21 days. Cell proliferation, epithelial-to-mesenchymal markers (EMT) and invasion potential were analyzed by, respectively, MTT, immunofluorescence and SDS-zymography. Our results show that cell proliferation was increased or decreased by BKV, respectively, in RWPE-1 and PC3 cells. BKV induced E-cadherin downregulation and vimentin expression in both control and BKV-infected cells RWPE-1, suggesting that uninfected cells underwent EMT. Matrix metalloproteinase-2 and 9 activity was increased in RWPE-1 cells after BKV infection. By contrast, BKV did not significantly modified the phenotype of PC3 cells. These preliminary results suggest that normal epithelial prostate cells RWPE-1 and PC3 are susceptible and permissive to BKV infection. However, RWPE-1 cells exhibit some phenotype modifications related to EMT, possibly induced by the papilloma virus used to obtain their immortalization, thus suggesting that further experiments will be necessary to define if they represent a good experimental model to study prostate cancer.

Do the Human Endogenous Retroviruses Play a Role in Colon Cancer

Long terminal repeat retroelements comprise about 8% of the human genome and include the human endogenous retroviruses (HERVs). Earllier it was suspected that HERVs can become active and be involved in the process of transformation of cells, through several oncogenic mechanisms. Abnormal expression of HERVs proteins has been reported for various types of cancer, such as melanoma, breast, prostate, and germ cell cancer, in which encoded transcripts or proteins are overexpressed in the tumor tissues. However, less is known about the association between the HERVs and the colon cancer development. We review the state of the art for colon cancer with respect to the HERVs that can be considered as an open area of investigation, potentially leading to future innovative diagnostic and therapeutic approaches.