Host control of human papillomavirus infection and disease

Most human papillomaviruses cause inapparent infections, subtly affecting epithelial homeostasis, to ensure genome persistence in the epithelial basal layer. As with conspicuous papillomas, these self-limiting lesions shed viral particles to ensure population level maintenance and depend on a balance between viral gene expression, immune cell stimulation and immune surveillance for persistence. The complex immune evasion strategies, characteristic of high-risk HPV types, also allow the deregulated viral gene expression that underlies neoplasia. Neoplasia occurs at particular epithelial sites where vulnerable cells such as the reserve or cuboidal cells of the cervical transformation zone are found. Beta papillomavirus infection can also predispose an individual with immune deficiencies to the development of cancers. The host control of HPV infections thus involves local interactions between keratinocytes and the adaptive immune response. Effective immune detection and surveillance limits overt disease, leading to HPV persistence as productive microlesions or in a true latent state.Support by the Medical Research Council (programme grant U117584278) has allowed the formulation of many of the ideas outlined in this review

'They wouldn't know how it feels . . .': characteristics of quality care from young people's perspectives: a participatory research project

Literature suggests there is a need to hear from children themselves about the quality of healthcare they receive and, although their views are increasingly sought, little is known about children’s definitions of ‘high or low quality care’. This article reports on a participatory, qualitative study that set out to explore with children and young people whether they could be involved in monitoring the quality of hospital care. Nine young people played an active role in the research process, collecting data from an additional 129 participants aged between 9 and 14. Five characteristics of quality care were identified: ‘technical expertise’, ‘friendly staff ’, ‘respect’, ‘choice’ and ‘explanations’

HPV16 E1^E4 protein is phosphorylated by Cdk2/cyclin A and relocalizes this complex to the cytoplasm

AbstractThe human papillomavirus type 16 E1^E4 protein is expressed abundantly in cells supporting viral DNA amplification, but its expression is lost during malignant progression. In cell culture, 16E1^E4 causes G2 cell cycle arrest by associating with and preventing the nuclear entry of Cdk1/cyclin B1 complexes. Here, we show that 16E1^E4 is also able to associate with cyclin A and Cdk2 during the G2 phase of the cell cycle. Only a weak association was apparent during S-phase, and progression through S-phase appeared unaffected. As with cyclin B1, the interaction of 16E1^E4 with cyclin A is dependent on residues T22/T23 and results in the accumulation of cyclin A in the cytoplasm where it colocalizes with 16E1^E4. 16E1^E4 serine 32 was found to be phosphorylated by Cdk2/cyclin A. We hypothesize that the interaction of 16E1^E4 with cyclin A may serve to increase the efficiency with which 16E1^E4 is able to prevent mitotic entry

Do Study Abroad Programs Enhance the Employability of Graduates?

Using data on a large sample of recent Italian graduates, this paper investigates the extent to which participation in study abroad programs during university studies impacts subsequent employment likelihood. To address the problem of endogeneity related to participation in study abroad programs, I use a combination of fixed effects and instrumental variable estimation where the instrumental variable is exposure to international student exchange schemes. My estimates show that studying abroad has a relatively large and statistically meaningful effect on the probability of being in employment three years after graduation. This effect is mainly driven by the impact that study abroad programs have on the employment prospects of graduates from disadvantaged (but not very disadvantaged) backgrounds, though positive but imprecise effects are also found for graduates from advantaged backgrounds

Combined condylomatosis and Buschke-Loewenstein tumor: case report & systematic review

Objectives: An undesired manifestation of HPV is the transformation of infected cells into neoplastic cells, with the subsequent development of precancerous intraepithelial lesions and in some instances cancer. The generally benign manifestations of HPV include asymptomatic and subclinical disease as well as anogenital condyloma acuminatum, warts and verruccosis. Certain HPV manifestations are however associated with poor outcome for the patient, and these include giant and multiple condylomas such as Buschke- Löwenstein tumor (BLT), and respiratory papillomatosis and their relapses. These conditions decrease the patient’s life quality, and have the potential to progress to malignancy, and are a particular problem for practitioners. Management of these patients is complicated due to the absence of therapies that can eliminate HPV and prevent wart recurrence, or medication that can cure genital warts and condylomas. Indeed, although there are many clinical reports describing the aggressive manifestation of genital warts in immune compromised individuals, the triggering mechanisms for such atypical lesions is not yet understood. Our objective here is to present a case report of combined condylomatosis and BLT in a patient with Henoch-Schönlein purpura and simultaneously infected with six HPV genotypes (6, 11, 18, 31, 43 & 56), and to systematicly review the literature in order to provide a better insight into these conditions. Methods: Clinical and laboratory parameters as well as a video of surgery of female patient (30 ys) with combined condylomatosis and BLT (the informed consent was obtained). Clinical and research literature over the last 15 years focusing on the immunological aspects of papillomavirus interaction with the innate and adaptive immune systems, and interference with the cellular and humoral host responses. Particular attention is given to the nature of papillomavirus clearance and persistence. Conclusions: Atypical manifestation of HPV was in our case related to systemic disease involving an autoimmune host response and long-term glucocorticoid treatment. Our review confirms that such atypical manifestations and the long-term persistence of HPV are often linked to disturbances in the hosts immune system. More specifically these comprise changes in the content of lymphocyte subsets (helper, cytotoxic and regulatory T-cells), NK cells and macrophages at HPV infected sites and in the blood, as well as changes in lymphocyte function related to the expression of INF-<& ®, IL-2; IL-4, IL-10, TGF®‚ and other cytokines

Expression of p16 and HPV E4 on biopsy samples and methylation of FAM19A4 and miR124-2 on cervical cytology samples in the classification of cervical squamous intraepithelial lesions

The decision to treat a cervical squamous intraepithelial lesion (SIL) by loop electrosurgical excision procedure (LEEP) relies heavily on a colposcopy-directed biopsy showing high-grade (H)SIL. Diagnosis is often supported by p16, an immunohistochemical (IHC) biomarker of high-risk (hr)HPV E7 gene activity. Additional potential markers include methylation of tumor suppressor genes FAM19A4/miR124-2 in cervical cytology for advanced transforming HSIL and the IHC marker HPV E4 for productive, potentially regressing lesions. In 318 women referred for colposcopy, we investigated the relationship between staining patterns of p16 and E4 IHC in the worst biopsy, and the relation of these to FAM19A4/miR124-2 methylation status in cytology. E4-positive staining decreased with increasing SIL/CIN grade from 41% in LSIL to 3% in HSIL/CIN3. E4 positivity increased with grade of p16 when p16 expression was limited to the lower two third of the epithelium (r = 0.378), but fell with expression over. Loss of E4 expression in the worst lesion was associated with the methylation of FAM19A4/miR124-2. We also examined whether these biomarkers can predict the histological outcome of the LE

Modulation of basal cell fate during productive and transforming HPV-16 infection is mediated by progressive E6-driven depletion of Notch

In stratified epithelia such as the epidermis, homeostasis is maintained by the proliferation of cells in the lower epithelial layers and the concomitant loss of differentiated cells from the epithelial surface. These differentiating keratinocytes progressively stratify and form a self-regenerating multi-layered barrier that protects the underlying dermis. In such tissue, the continual loss and replacement of differentiated cells also limits the accumulation of oncogenic mutations within the tissue. Inactivating mutations in key driver genes, such as TP53 and NOTCH1, reduce the proportion of differentiating cells allowing for the long-term persistence of expanding mutant clones in the tissue. Here we show that through the expression of E6, HPV-16 prevents the early fate commitment of human keratinocytes towards differentiation and confers a strong growth advantage to human keratinocytes. When E6 is expressed either alone or with E7, it promotes keratinocyte proliferation at high cell densities, through the combined inactivation of p53 and Notch1. In organotypic raft culture, the activity of E6 is restricted to the basal layer of the epithelium and is enhanced during the progression from productive to abortive or transforming HPV-16 infection. Consistent with this, the expression of p53 and cleaved Notch1 becomes progressively more disrupted, and is associated with increased basal cell density and reduced commitment to differentiation. The expression of cleaved Notch1 is similarly disrupted also in HPV-16-positive cervical lesions, depending on neoplastic grade. When taken together, these data depict an important role of high-risk E6 in promoting the persistence of infected keratinocytes in the basal and parabasal layers through the inactivation of gene products that are commonly mutated in non-HPV-associated neoplastic squamous epithelia

HPV16 and 18 genome amplification show different E4-dependence, with 16E4 enhancing E1 nuclear accumulation and replicative efficiency via its cell cycle arrest and kinase activation functions

To clarify E1^E4's role during high-risk HPV infection, the E4 proteins of HPV16 and 18 were compared side by side using an isogenic keratinocyte differentiation model. While no effect on cell proliferation or viral genome copy number was observed during the early phase of either virus life cycle, time-course experiments showed that viral genome amplification and L1 expression were differently affected upon differentiation, with HPV16 showing a much clearer E4 dependency. Although E4 loss never completely abolished genome amplification, its more obvious contribution in HPV16 focused our efforts on 16E4. As previously suggested, in the context of the virus life cycle, 16E4s G2-arrest capability was found to contribute to both genome amplification success and L1 accumulation. Loss of 16E4 also lead to a reduced maintenance of ERK, JNK and p38MAPK activity throughout the genome amplifying cell layers, with 16E4 (but not 18E4) co-localizing precisely with activated cytoplasmic JNK in both wild type raft tissue, and HPV16-induced patient biopsy tissue. When 16E1 was co-expressed with E4, as occurs during genome amplification $\textit{in vivo}$, the E1 replication helicase accumulated preferentially in the nucleus, and in transient replication assays, E4 stimulated viral genome amplification. Interestingly, a 16E1 mutant deficient in its regulatory phosphorylation sites no longer accumulated in the nucleus following E4 co-expression. E4-mediated stabilisation of 16E2 was also apparent, with E2 levels declining in organotypic raft culture when 16E4 was absent. These results suggest that 16E4-mediated enhancement of genome amplification involves its cell cycle inhibition and cellular kinase activation functions, with E4 modifying the activity and function of viral replication proteins including E1. These activities of 16E4, and the different kinase patterns seen here with HPV18, 31 and 45, may reflect natural differences in the biology and tropisms of these viruses, as well as differences in E4 function.The work was supported by the UK Medical Research Council (grant ref. MC_PC_13050 / Molecular biology of human papilloma virus infection to JD, http://gtr.rcuk.ac.uk/ project/A691 306C-DAA9- 4078-B5D E- 2096CF3C8A18)