PBMCs are additional sites of productive infection of bovine papillomavirus type 2

Bovine papillomavirus vertical transmission: BPV diversity and expression in maternal and fetal tissues

Bovine Papillomaviruses (BPVs) constitute a diverse group within the Papillomaviridae family, playing a crucial role in bovine health and economic considerations. This study investigates the dynamics of vertical transmission of BPV in cattle, focusing on five cows and their reproductive tissues, as well as three gravid cows and their fetuses. DNA and RNA samples were extracted from the warts, fetal skin, placenta, uterus, ovary, and blood of cows, as well as the skin and blood of fetuses. Polymerase Chain Reaction (PCR) targeted BPV types 1-6 and 8-14, was assessed in both cows and fetuses. Additionally, Reverse Transcription PCR (RT-PCR) examined BPV-2 E5 oncogene expression in the skin and reproductive sites of mother cows and fetuses. Our findings unveil a rich diversity of BPV types, including BPV-2, 3, 9, 10, 12, and 14, present in both maternal and fetal tissues. Intriguingly, certain types, namely BPV-4, 6, 8, and 11, were exclusively identified in maternal tissues A higher diversity of BPVs was observed in cow warts, followed by cow blood, fetal blood, and fetal skin. Strikingly similar BPV types in gravid cow blood and fetuses suggest primary dissemination through the bloodstream and transmission via the placenta, though detected in lower numbers in cow uterus and ovary. Histopathological analysis revealed no abnormalities in the reproductive tissues despite the presence of BPV. However, in one bladder sample from a cow that did not consume bracken fern, urothelial neoplasia in situ was observed. The study extends beyond detection, exploring the expression of the BPV-2 E5 oncogene in fetal tissues, providing insights into potential cell implications. Comparative analyses with previous studies highlight the uniqueness of our investigation, encompassing a broader array of BPV types in the gravid cows and their fetuses. The findings not only establish a foundation for further investigations into the mechanisms of vertical transmission but also highlight the need for targeted interventions and surveillance strategies to mitigate potential health risks associated with specific BPV types.

Maternal human papillomavirus infection and the risk of congenital malformations: A nationwide population-based cohort study

Previous research has explored theories regarding the vertical transmission of human papillomavirus (HPV) infection and its association with adverse pregnancy and perinatal outcomes. However, the impact of maternal HPV infection on congenital anomalies (CAs) in offspring remains relatively understudied. We conducted a population-based cohort study linking the Taiwan Birth Registry, Taiwan Death Registry, and National Health Insurance Research Database, in which newborns born in Taiwan between 2009 and 2015 were included. We established a maternal HPV infection cohort comprising 37 807 newborns and matched them with a comparison group of 151 228 newborns at a 1:4 ratio based on index year, age, and sex. The study examined a composite outcome and subgroups of different types of congenital malformations. Differences in cumulative incidence of CAs were assessed using Kaplan-Meier curves and log-rank tests. Adjusted hazard ratios (aHRs) were estimated using Cox proportional hazard regressions. No significant association was found between HPV infection and the broad spectrum of CAs (aHR: 1.04, 95% confidence interval [CI]: 0.98-1.10; log-rank test p = 0.14). However, we observed a 19% increased risk of musculoskeletal CAs in the maternal HPV infection group (aHR: 1.19; 95% CI: 1.05-1.34) compared to those without maternal HPV exposure. Other factors, including the type of HPV (aHR: 0.65; 95% CI: 0.16-2.63), the timing of exposure (during or before pregnancy), and maternal age (aHR for <30 years: 1.02, 95% CI: 0.94-1.1; aHR for 30-39 years: 1.05, 95% CI: 0.99-1.11; aHR for ≥40 years: 0.88, 95% CI: 0.67-1.17), did not significantly affect the risk for any CA. In conclusion, gestation detection of HPV infection was associated with musculoskeletal CAs but not other major CAs. Prospective studies are warranted to elucidate the necessity of prenatal screening in populations at risk.

Detection of Human Papillomavirus DNA in Paired Peripheral Blood and Cervix Samples in Patients with Cervical Lesions and Healthy Individuals

This study evaluated the presence of Human Papillomavirus (HPV) DNA in the cervix and peripheral blood of women with cervical intraepithelial neoplasia (CIN I, II, and III) and healthy individuals. Overall, 139 paired peripheral blood and cervix samples of healthy women and women with CIN I, II, and III (n = 68) were tested for HPV DNA by using standard procedures. Polymerase chain reaction (PCR) sequencing determined HPV types. Quantification of HPV16 E6 and E2 genes was performed to determine viral load and physical state. HPV DNA was detected in the cervix (21.1% in healthy individuals; 48.8–55.5% in CIN patients), blood (46.4% in healthy individuals; 44.1–77.7% in CIN patients) and paired peripheral blood and cervix samples (24% in healthy individuals; 32.5–44.4% in CIN patients). The most frequent types found in the cervix were HPV16, 18, 31, 33, 58, and 70, while HPV16, 18, 33, 58, and 66 were the most frequent types found in the blood. HPV DNA in the cervix was associated with previous sexually transmitted infections (STIs) (p = 0.023; OR: 2.978; CI:1.34–7.821), HPV DNA in the blood (p = 0.000; OR: 8.283; CI:3.700–18.540), and cervical lesions (CIN I/II or III) (p = 0.007). Binomial logistic regression showed that HPV DNA in the blood (p = 0.000; OR: 9.324; CI:3.612–24.072) and cervical lesions (p = 0.011; OR: 3.622; CI:1.338–9.806) were associated with HPV DNA in the cervix. However, we did not find an association between HPV DNA in the blood and cervical lesions (p = 0.385). Our results showed that only HPV DNA found in the cervix was associated with cervical lesions.

HPV infection as a risk factor for atherosclerosis: A connecting hypothesis

Atheromatous plaques occurring in large arteries are common and life-threatening lesions. Multiple factors are involved in the pathogenesis of atheromatous plaques, such as hyperlipidaemia and hypercholesterolaemia, high blood pressure and chronic systemic inflammation. Recent findings have suggested that infection with high-risk human papillomavirus (HPV) may increase the risk of developing atheromatous plaques. However, HPV is considered a tissue-specific virus with a strong tropism towards squamous epithelial cells, and the mechanisms whereby it may promote the development of atheromas remain unclear. Here, we propose a connecting hypothesis to explain the possible causative role of HPV on atheroma development. We hypothesize that HPV infection may promote atheroma formation in infected patients by enhancing systemic inflammation or by directly targeting blood vessels via nucleic acids carried by extracellular vesicles such as exosomes. The pro-inflammatory effects of HPV and the release of extracellular vesicles by HPV-transformed cells are well documented in scientific literature. Possible experimental approaches to test this hypothesis are also discussed, especially experiments employing transgenic mice bearing HPV16 transgenes. If correct, this hypothesis would have major implications for the prevention of cardiovascular diseases, especially due to the preventable nature of HPV infection through vaccination.

Detection and quantitation of human papillomavirus DNA in peripheral blood mononuclear cells from blood donors

Human papillomavirus (HPV) is the etiological agent of cervical cancer. Also, HPV has been associated with anogenital cancer, oropharyngeal cancer, genital warts, and other dermatological diseases. HPV infects epithelial cells and their replication is closely linked to epithelial differentiation. The presence of HPV DNA in peripheral blood mononuclear cells (PBMC) has been reported in some patients with head and neck cancer, cervical cancer, and other genital diseases. However, the presence of HPV DNA in blood in asymptomatic subjects is still unresolved. The objective of this study was to evaluate the presence of HPV DNA in PBMC from asymptomatic blood donors. Blood samples were collected from 207 healthy Chilean blood donors. Genomic DNA was extracted from PBMC and HPV DNA detection was performed by real-time quantitative polymerase chain reaction assays with GP5+/6+ primers. HPV typing was carried out by genetic sequencing of a 140 to 150 bp fragment of the L1 gene. HPV DNA was detected in 6.8% (14/207) of blood donors. Single HPV infections were detected in seven blood donors. High-risk HPV was found in 6.3% (13/207) of cases: nine blood donors were infected with HPV-16, five with HPV-18, two with HPV-51, and one case was infected with either 32, 33, 45, 59, 66, 70, or 82. The median viral load value was 21.3 copies/mL blood or 13.4 HPV (+) cells per 10 ⁴ PBMC. These results show that HPV DNA is present in PBMC from healthy blood donors and it suggests that blood could be a new route of HPV dissemination.

FUNDC1-mediated mitophagy in bovine papillomavirus-infected urothelial cells

E5 protein, the major oncoprotein of the bovine Deltapapillomavirus genus, has been detected in 17 of the 19 urothelial cancers by molecular and morphological procedures. In 10 urothelial cancers, the oxygen sensitive subunit HIF-1α, which is upregulated by hypoxia, was overexpressed. Mitophagy, the selective autophagic removal of dysfunctional mitochondria, was upregulated in hypoxic neoplastic cells infected by BPVs which was mediated by FUNDC1, a mitochondrial outer-membrane protein. The FUNDC1 receptor was amplified by PCR, and amplicon sequencing showed a 100% homology with bovine FUNDC1 sequences deposited in GenBank (accession number: NM_001104982). Both transcripts and protein levels of FUNDC1 were significantly decreased in hypoxic neoplastic cells relative to healthy, non-neoplastic cells. FUNDC1 interacted with the LC3 protein, a marker of autophagosome (mitophagosome) membrane, the Hsc70/Hsp70 chaperone, and Bag3 co-chaperone. Bag3 may play a role in mitophagosome formation together with the Synpo2 protein, and may be involved in the degradation of Hsc70/Hsp70-bound CHIP-ubiquitinated cargoes, in association with its chaperone. Ultrastructural findings revealed the presence of mitochondria exhibiting severe fragmentation and loss of cristae, as well as numerous mitochondria-containing autophagosomes. Total and phosphorylated GTPase dynamin-related protein 1 (DRP1), which plays a crucial role in mitochondrial fission, a pre-requisite for mitophagy, was overexpressed at the mitochondrial level. Total and phosphorylated mitochondrial fission factor (Mff), mitochondrial fission protein 1 (Fis1), mitochondrial dynamics 51 (MiD51), and MiD49, which are DRP1 receptors responsible and/or co-responsible for its mitochondrial recruitment were overexpressed.

Haematological and immunophenotypic evaluation of peripheral blood cells of cattle naturally infected with bovine papillomavirus

Papillomaviruses are among the most widespread animal viruses, with many hosts harbouring multiple virus types. The present study aimed to evaluate the haematological and immunophenotypic profile of cattle infected with bovine papillomavirus (BPV). Blood samples were collected from 10 animals with clinical cutaneous BPV and without clinical papillomatosis (control). Haematological analysis demonstrated a significant reduction in haemoglobin and haematocrit for BPV-infected animals. The results also showed an increase of natural killer cells and a decrease of γδ⁺ T-cells and the CD4⁺/CD8⁺ ratio for the BPV group when compared to the control group. The infection was also found to stimulate a pro-inflammatory profile with the participation of CD8⁺T cells producing elevated IFN-γ and IL-17. These findings, although preliminary, provide a better understanding of the immune response of cattle infected with BPV.

Molecular Detection of Bovine Papillomavirus DNA in the Placenta and Blood of Healthy Mares and Respective Foals

Despite the characteristic species specificity of Papillomaviruses (PVs), the bovine papillomavirus (BPV) types 1, 2, and-more rarely-13, can cross-infect equids, where they are involved in the pathogenesis of sarcoid neoplasms. Sarcoids are locally invasive fibroblastic skin tumors that represent the most common skin neoplasms in horses worldwide. The transmission mechanism of BPV is still controversial in horses. Thus far, direct and indirect routes have been implicated, while vertical transmission has been suggested after the detection of viral DNA in the semen of healthy stallions. Testing of the blood and placenta of non-sarcoid baring mares and their respective foals revealed that the equine placenta can harbor BPV DNA, leading us to speculate a possible prenatal vertical DNA transmission in equids.

Congenital papillomavirus infection in cattle: Evidence for transplacental transmission

Vertical transmission of bovine papillomavirus (BPV) infection was investigated on livers and kidneys of four foetuses from cows suffering from BPV-2-associated urothelial cancers of the urinary bladder. PCR analysis revealed the presence of BPV-2 E5 DNA in the livers and kidneys of two foetuses. Amplified DNA fragments, composed of 502 bp, showed a 100% homology with BPV-2 sequences (GenBank accession number: M20219.1). BPV-2 was found to be transcriptionally active. Indeed, reverse transcriptase (RT)-PCR showed BPV-2 E5 transcripts. Sequencing of amplified cDNA, composed of 154 bp, showed a 100% identity with BPV-2 E5 sequences (GenBank accession number: M20219.1). Western blot analysis revealed the presence of dimers of E5 oncoprotein. Furthermore, a statistically significant increase of the phosphorylated (activated) form of the platelet-derived growth factor ß receptor (PDGFßR) was also detected in the fetal tissues. PDGFßR is believed to form the most important interaction with the E5 oncoprotein, thus regulating biological activity of virus protein. The strong concordance between virus found in fetal organs with virus detected in infected mothers provides evidence that BPV-2 can spread through blood and vertical infection occurs via transplacental transmission. Finally, molecular findings of this study raise unsolved questions about the potential role of BPVs in reproductive disorders. The presence of E5 oncoprotein, as in adult organs, may also activate the constitutive receptor PDGFßR in foetal organs, which plays a pivotal role in angiogenesis and embryonic development. Therefore, abnormal phosphorylation of PDGFßR may be involved in vascular and organogenesis abnormalities other than cancer.

Detection of bovine papillomavirus type 2 DNA in calf conjunctival myofibroblastoma

An 8-month-old male Japanese Black calf was referred for the evaluation of a slow-growing conjunctival mass in the right eye. A superficial keratectomy was performed followed by recurrence on two occasions. No metastases were found in surrounding tissues. Histological, immunohistochemical, and ultrastructural investigation revealed that both the primary and the recurrent lesions were benign, conjunctival, myofibroblastomas. Interestingly, bovine papillomavirus type 2 (BPV-2) DNA was detected in both myofibroblastoma lesions. Archival bovine myofibroblastomas from the vulva and neck were also analyzed for papillomaviral genomes. BPV-2 DNA was also amplified from these lesions. To the best of our knowledge, this is the first report describing a potential causal relationship between BPV-2 infection and conjunctival myofibroblastoma.

Detection of bovine Deltapapillomavirus DNA in peripheral blood of healthy sheep (Ovis aries)

Blood samples from 65 sheep were tested for the presence of bovine Deltapapillomavirus (δPVs) DNA. The sheep were divided into three groups. Sheep in groups 1 and 2 were from Sardinia and Campania, respectively, and were in contact with cattle and grazed on lands contaminated with bracken fern. Sheep in Group 3 lived in closed pens and had no contact with cattle. These sheep were fed hay that did not contain bracken fern. Bovine δPV E5 DNA was detected in blood from 24 of 27 (89%) sheep in Group 1. A single bovine δPV type was detected in the blood from nine (33%) sheep, including the detection of bovine δPV-1 DNA in four sheep, bovine δPV-2 in four and δPV-13 in one sheep. Two δPV types were detected in 33% of the sheep, and three bovine δPV types were detected in 22% of the sheep. Bovine δPVs were detected in 17 of 20 (85%) sheep from Group 2. The detection rate by a single δPV type was 40% with just δPV-1 DNA amplified from two, just δPV-2 DNA from four, and just δPV-13 DNA from two sheep. Two and three δPVs were detected in 30% and 15%, respectively. All sequenced amplicons showed a 100% identity with papillomaviral E5 DNA deposited in GenBank. Bovine δPV-14 DNA sequences were not detected from any sheep. No bovine δPV DNA was revealed in blood samples from sheep in Group 3. The detection of bovine δPV DNA in the blood of sheep means that sheep may be able to be infected by these PVs. This suggests that bovine δPVs could potentially be a previously unrecognized cause of disease in sheep. Furthermore, it is possible that sheep could act as a reservoir for these viruses.

Human papillomavirus DNA detection in plasma and cervical samples of women with a recent history of low grade or precancerous cervical dysplasia

Circulating HPV DNA has been previously described in women with advanced stages of cervical cancer and has been suggested to be a prognostic marker of disease recurrences and metastases. Only a few studies have reported the presence of HPV DNA in bloodstream of patients with low grade or precancerous cervical lesions. This study aimed to define if HPV DNA could be detected in plasma samples of 120 women referred for a recent history of cervical dysplasia who presented with lesions ranging from High Squamous Intraepithelial Lesion (H-SIL) to regressed normal cytology. HPV DNA detection was carried out in both plasma and cervical samples using type-specific real-time quantitative PCR assays identifying oncogenic HPV 16, 18, 31, 33, 45, 51 and 52.

Overall, 34.2% (41/120) of plasma samples were shown to be positive for HPV DNA detection; HPV 45 (46.3%), HPV-51 (29.6%), and HPV 16 (18.5%) were the most frequently identified genotypes. The rate of HPV detection in paired cervical and plasma samples increased with advancing disease stage, ranging from 15.4% in women with regressed lesions to 38.9% in women with HSIL; HPV 16 resulted the most common genotype identified in women found to be HPV DNA positive in both cervical and plasma samples. Moreover, HPV 16 showed the highest median viral load value in both cervical and plasma samples, with 48,313 copies/10⁴ cells and 1,099 copies/ml, respectively.

Results obtained in this study confirm that HPV DNA can be detected and quantified in plasma samples of women with asymptomatic cervical infection. Further knowledge on HPV dissemination through the blood stream of women with cervical lesions would be very important in better understanding the natural history of HPV infection as well as its potential role in other distant tumors.

Papillomaviruses: a systematic review

In the last decades, a group of viruses has received great attention due to its relationship with cancer development and its wide distribution throughout the vertebrates: the papillomaviruses. In this article, we aim to review some of the most relevant reports concerning the use of bovines as an experimental model for studies related to papillomaviruses. Moreover, the obtained data contributes to the development of strategies against the clinical consequences of bovine papillomaviruses (BPV) that have led to drastic hazards to the herds. To overcome the problem, the vaccines that we have been developing involve recombinant DNA technology, aiming at prophylactic and therapeutic procedures. It is important to point out that these strategies can be used as models for innovative procedures against HPV, as this virus is the main causal agent of cervical cancer, the second most fatal cancer in women.

Intranuclear Inclusions in Renal Tubular Epithelium in Immunodeficient Mice Stain with Antibodies for Bovine Papillomavirus Type 1 L1 Protein

The kidneys from six immunodeficient mice examined by Cerberus Sciences and the Animal Resources Centre, displayed karyomegaly with pale eosinophilic, intranuclear inclusions upon histopathological examination. Electron microscopy performed on kidney tissue from 5/6 mice demonstrated margination of the chromatin in large nuclei. Laboratory tests were used to detect nucleic acid of papillomaviruses, polyomaviruses, circoviruses and anelloviruses (4/6 mice), a specific PCR was used to detect murine polyomavirus (1/6), and a panel of serological tests was used to detect seroconversion to major murine pathogens (1/6). All molecular and serological tests were negative. Immunohistochemistry using polyclonal anti-bovine papillomavirus type 1 (BPV-1) L1 antibody, Camvir monoclonal anti-papillomavirus antibody (directed against the seven amino acids GFGAMDF found in human papillomavirus (HPV) 16 L1 protein), a commercially available mixture of two monoclonal antibodies, anti-BPV-1 L1/1H8 + Camvir antibodies, and a monoclonal anti-Hsc70 antibody revealed specific, positive staining of murine renal tubular epithelial intranuclear inclusions in 6/6 mice using the anti-BPV-1 L1 containing antibodies only. Methyl pyronin green, PAS and Feulgen histochemical reactions revealed that the intranuclear inclusions did not consist of RNA, DNA or carbohydrate. An immunohistochemical method now exists that can be used to confirm and evaluate suspected cases of murine inclusion body nephropathy.

Detection and quantification of bovine papillomavirus type 2 in urinary bladders and lymph nodes in cases of Bovine Enzootic Hematuria from the endemic region of Azores

Bovine Enzootic Hematuria (BEH) is a disease with a severe impact on production indexes and characterized by the development of bovine urinary bladder tumors, particularly in the Azores archipelago. The purpose of this study was to investigate and quantify BPV2 tissue distribution in bovine urinary bladder tumors, normal bladders, and iliac lymph nodes of cattle from the Azores. A real-time PCR system targeting the L1 gene was developed and allowed for the specific detection of the virus. BPV2 DNA was detected in a large proportion of the samples tested, both from neoplastic and healthy tissues, indicating that this virus is very prevalent in the bovine population of the Azores. Moreover, all types of tissues tested were positive, confirming a wide viral distribution within the infected animal. Bovine cutaneous papillomas sampled from Portuguese mainland dairy cattle were used as controls. Viral load ranged between 2.2×10(4) copies/cell in the skin papillomas, and 0.0002 copies/cell in the urinary bladders tumors from the Azores. This is the first report presenting quantitative data on BPV2 infection in bovine urinary bladder lesions from the Azores. This approach will provide a useful tool to evaluate the role of BPV2 not only in the pathogenesis BEH but also in cell transformation mechanisms.

Bovine Papillomavirus Type 13 Expression in the Urothelial Bladder Tumours of Cattle

Bovine papillomavirus type 13 (BPV-13), a novel Deltapapillomavirus, has been found associated with urothelial tumours of the urinary bladder of cattle grazing on lands infested with bracken fern. BPV-13 was detected in 28 of 39 urothelial tumours. Diagnosis was based on sequencing of L1 and E5 amplicons from tumour samples. The nucleotide sequences generated from these amplicons showed a 100% homology with the sequences of BPV-13 L1 and E5 DNA found in Brazil from a fibropapilloma of the ear in a cow and from equine sarcoids in two horses. GenBank accession number of our representative BPV-13 sequences is JQ798171.1. Furthermore, mRNA encoding BPV-13 E5 oncoprotein was also documented, and its expression was also shown by immunohistochemistry and immunofluorescence in the basal and suprabasal urothelial tumour cells. In twenty-three tumours, BPV-13 was simultaneously found with BPV-2, a Deltapapillomavirus genus, species 4. The latter virus was detected by amplifying and sequencing a 154-bp-sized DNA fragment of BPV-2 E5. In addition, BPV-13 by itself was seen to be expressed in five BPV-2-negative urothelial tumours. This study shows that BPV-13 is present in urothelial tumour cells thus sharing biological properties with BPV-1 and BPV-2. Although further studies are needed, BPV-13 appears to be another worldwide infectious agent responsible for a distressing disease causing severe economic losses in cattle industry.

Male infertility: a public health issue caused by sexually transmitted pathogens

Sexually transmitted diseases (STDs) are caused by several pathogens, including bacteria, viruses and protozoa, and can induce male infertility through multiple pathophysiological mechanisms. Additionally, horizontal transmission of STD pathogens to sexual partners or vertical transmission to fetuses and neonates is possible. Chlamydia trachomatis, Ureaplasma spp., human papillomavirus, hepatitis B and hepatitis C viruses, HIV-1 and human cytomegalovirus have all been detected in semen from symptomatic and asymptomatic men with testicular, accessory gland and urethral infections. These pathogens are associated with poor sperm quality and decreased sperm concentration and motility. However, the effects of these STD agents on semen quality are unclear, as are the effects of herpes simplex virus type 1 and type 2, Neisseria gonorrhoeae, Mycoplasma spp., Treponema pallidum and Trichomonas vaginalis, because few studies have evaluated the influence of these pathogens on male infertility. Chronic or inadequately treated infections seem to be more relevant to infertility than acute infections are, although in many cases the exact aetiological agents remain unknown.

Bovine and Human Papillomaviruses

Fifty years ago, inoculation with bovine papillomavirus (BPV) was found to cause mesenchymal tumors of the skin in cattle and horses, as well as tumors of the bladder in cattle. Subsequent to these studies of BPVs, human papillomaviruses (HPVs) were found to cause cervical cancer resulting in intense research into papillomaviruses. During the past 50 years, the ways that HPVs and BPVs cause disease have been investigated, and both HPVs and BPVs have been associated with an increasingly diverse range of diseases. Herein, the biology, oncogenic mechanisms, and diseases associated with BPVs are compared with those of HPVs. As reviewed, there are currently significant differences between BPVs and HPVs. However, research 50 years ago into BPVs formed a prologue for the recognition that papillomaviruses have a significant role in human disease, and it is possible that future research may similarly reveal that BPVs are less different from HPVs than is currently recognized.

Detection of Different Bovine Papillomavirus Types and Co-infection in Bloodstream of Cattle

Bovine papillomavirus (BPV) is a diverse group of double-stranded DNA oncogenic viruses. BPVs are classically described as epitheliotropic, however, they have been detected in body fluids, such as blood and semen. The presence of BPV in these sites can have implications for the dissemination of BPV. The aim of this study was to verify the prevalence of BPV types in cattle blood. A total of 57 blood samples were analyzed by PCR using BPV type-specific primers to BPVs 1-6 and 8-10, and subsequent sequencing. Sequencing quality was determined using Staden package with Phred 20. Similarity analysis was performed with BioEdit and BLAST programs to assess the identity with known BPV types. Statistical analysis was performed by Fisher's exact test. The results showed seven different types of BPVs in the blood, with the exception of BPV 5 and 9. This is the first study that demonstrates BPVs 3, 6, 8 and 10 DNA in cattle blood. BPVs 1 and 2 were the viral types most frequent in blood, while BPVs 4 and 10 were the least frequent types. All the samples showed co-infection by at least two BPV types. These data suggest that several BPV types may infect blood cells at the same time and demonstrate the possibility that the BPV infection in non-epithelial tissue can occur without restriction to one or two viral types. These results can contribute to future studies aimed at the control and prevention of papillomaviruses.

Bovine papillomavirus type 2 (BPV-2) E5 oncoprotein binds to the subunit D of the V₁-ATPase proton pump in naturally occurring urothelial tumors of the urinary bladder of cattle

Background

Active infection by bovine papillomavirus type 2 (BPV-2) was documented for fifteen urinary bladder tumors in cattle. Two were diagnosed as papillary urothelial neoplasm of low malignant potential (PUNLMP), nine as papillary and four as invasive urothelial cancers.

Methods and Findings

In all cancer samples, PCR analysis revealed a BPV-2-specific 503 bp DNA fragment. E5 protein, the major oncoprotein of the virus, was shown both by immunoprecipitation and immunohistochemical analysis. E5 was found to bind to the activated (phosphorylated) form of the platelet derived growth factor β receptor. PDGFβR immunoprecipitation from bladder tumor samples and from normal bladder tissue used as control revealed a protein band which was present in the pull-down from bladder cancer samples only. The protein was identified with mass spectrometry as “V₁-ATPase subunit D”, a component of the central stalk of the V₁-ATPase vacuolar pump. The subunit D was confirmed in this complex by coimmunoprecipitation investigations and it was found to colocalize with the receptor. The subunit D was also shown to be overexpressed by Western blot, RT-PCR and immunofluorescence analyses. Immunoprecipitation and immunofluorescence also revealed that E5 oncoprotein was bound to the subunit D.

Conclusion

For the first time, a tri-component complex composed of E5/PDGFβR/subunit D has been documented in vivo. Previous in vitro studies have shown that the BPV-2 E5 oncoprotein binds to the proteolipid c ring of the V₀-ATPase sector. We suggest that the E5/PDGFβR/subunit D complex may perturb proteostasis, organelle and cytosol homeostasis, which can result in altered protein degradation and in autophagic responses.

Bovine papillomavirus E2 and E5 gene expression in sperm cells of healthy bulls

Papillomaviruses are found in epithelial lesions and are linked to different carcinogenic processes in humans and other animals. Although BPV has been characterized as epitheliotropic, the presence of viral DNA has been detected in other tissues and fluids, such as fresh semen. The aim of this study was to evaluate the presence and expression of BPV in sperm cells of bulls (Bos taurus) asymptomatic for papillomatosis. A PCR assay was carried out with specific primers to test BPV2 in 26 semen samples. The presence of BPV transcripts was assessed by RT-PCR to E2 and E5 genes. BPV2 DNA was detected in nine out of 26 samples and the expression of E2 and E5 were detected in five out of nine BPV positive samples. This is the first record of BPV2 expression in bull sperm cells.

Human papillomavirus proteins are found in peripheral blood and semen Cd20+ and Cd56+ cells during HPV-16 semen infection

Background

Human papillomavirus (HPV) currently represents an important risk factor for cancer development and infertility in humans. Whilst binding of HPV to spermatozoa has been associated with male infertility, an investigation about the presence of HPV-DNA in non-spermatozoal semen cells is lacking. Previous findings documented the presence of HPV in peripheral blood leukocytes. The aim of this study was to investigate the expression of HPV markers in semen and blood leukocytes during HPV-16 infection.

Methods

A total of 32 subjects, 16 patients affected by HPV-16 semen infection and 16 controls, were evaluated in our andrological centre and enrolled in the study. Semen non-spermatozoal cells from all subjects were isolated and evaluated for the expression of HPV-16 markers (DNA and L1, E6 proteins) and further characterized for their molecular phenotype. Analogue determination was performed on peripheral blood mononuclear cells.

Results

The presence of HPV-DNA by FISH analysis in a round cell population from semen, confirmed to be CD45+ leukocytes, was observed. These HPV-DNA containing-cells also displayed HPV-16-E6 and HPV-16-L1 viral proteins and, upon further investigation, were found to be CD20+ and CD56+, likely phenotypes of B cells and natural killer cells (NK) respectively. In 25% of the patient group, a very small population of peripheral blood mononuclear cells was found to be positive for HPV-DNA via FISH. These cells displayed the CD20+ and CD56+ phenotype alike. None of the control subjects displayed HPV-DNA in either semen or peripheral blood.

Conclusion

Considering the role of CD20+ and CD56+ cell populations in the antiviral immune response, the detection of HPV markers on leukocytes may reflect the presence of virus particles within the endosomal compartment. However, the presence of HPV markers in circulating mononuclear cells raise concerns about the risk of developing cancers to distal organs.

Sarcoid-derived fibroblasts: links between genomic instability, energy metabolism and senescence

Bovine papillomavirus 1 (BPV-1) is a well recognized etiopathogenetic factor in a cancer-like state in horses, namely equine sarcoid disease. Nevertheless, little is known about BPV-1-mediated cell transforming effects. It was shown that BPV-1 triggers genomic instability through DNA hypomethylation and oxidative stress. In the present study, we further characterized BPV-1-positive fibroblasts derived from sarcoid tumors. The focus was on cancer-like features of sarcoid-derived fibroblasts, including cell cycle perturbation, comprehensive DNA damage analysis, end-replication problem, energy metabolism and oncogene-induced premature senescence. The S phase of the cell cycle, polyploidy events, DNA double strand breaks (DSBs) and DNA single strand breaks (SSBs) were increased in BPV-1-positive cells compared to control fibroblasts. BPV-1-mediated oxidative stress may contribute to telomere dysfunction in sarcoid-derived fibroblasts. Loss of mitochondrial membrane potential and concurrent elevation in intracellular ATP production may be a consequence of changes in energy-supplying pathways in BPV-1-positive cells which is also typical for cancer cells. Shifts in energy metabolism may support rapid proliferation in cells infected by BPV-1. Nevertheless, sarcoid-derived fibroblasts representing a heterogeneous cell fraction vary in some aspects of metabolic phenotype due to a dual role of BPV-1 in cell transformation and oncogene-induced premature senescence. This was shown with increased senescence-associated β-galactosidase (SA-β-gal) activity. Taken together, metabolic phenotypes in sarcoid-derived fibroblasts are plastic, which are similar to greater plasticity of cancer tissues than normal tissues.

Bovine papillomavirus: opening new trends for comparative pathology

For many years, research on bovine papillomavirus (BPV) has contributed to the understanding of papillomavirus-induced pathology in humans and animals. The present review shows how recent studies on BPV keep providing evidence concerning key points in viral infection, such as the expression of viral proteins in lymphocytes and the occurrence of productive infections of the placenta. Studies on BPV-induced tumours also provide important information concerning the mechanisms of oncogenesis and immune evasion, as in the cases of connexin 43 down-regulation with loss of intercellular gap junctions and Toll-like receptor 4 (TLR4) down-regulation in equine sarcoids. The biological functions of viral proteins are also being further clarified, as in the case of E2, which was recently shown to load BPV genomes into host chromosomes during the S phase, a process mediated by the ChlR1 protein. In the near future, the ongoing efforts to characterize and classify additional emerging BPV types are likely to broaden even further the possibilities for research.

Bovine papillomavirus clastogenic effect analyzed in comet assay

Bovine papillomavirus (BPV) is an oncogenic virus related to serious livestock diseases. Oncoproteins encoded by BPV are involved in several steps of cellular transformation and have been reported as presenting clastogenic effects in peripheral lymphocytes and primary culture cells. The aim of this study was to evaluate the clastogenic potential of BPV types 1, 2, and 4 by comet assay. Peripheral blood was collected from 37 bovines, 32 infected with different levels of papillomatosis (12 animals have no affection) and five calves, virus free (negative control). The viral identification showed presence of more than one virus type in 59.375% of the infected animals. Comet assay was performed according to alkaline technique. The Kruskal-Wallis test showed statistical difference between the negative control group and infected animals (P = 0.0015). The Dunn post hoc test showed difference comparing the infected animals with calves. Mann-Whitney U test verified no difference between animals infected with only one viral type and animals presenting more than one viral type. The comet assay is considered an efficient tool for assessment of damage in the host chromatin due to viral action, specifically highlighting viral activity in blood cells.

Bovine papillomavirus type 2 infection and a series of mesenchymal tumors of the urinary bladder in cattle

This report describes the histopathology of two hundred and fifty-three mesenchymal tumors of the urinary bladder in cattle grazing on lands rich in bracken fern. Approximately 80% were hemangiomas and angiosarcomas. Hemangioma (capillary, cavernous, and large vessels) was the most frequent mesenchymal tumor and was more common than angiosarcoma. Although the appearance of endothelial cells can vary remarkably, epithelioid angiosarcomas, often containing multinucleated cells, were the most frequent malignant vascular tumors. Hemangiopericytoma and tumors of muscle and soft connective tissue origin, alone and/or in association with tumor-like lesions, were less frequently seen. Furthermore, forty-five cases of intravascular papillary endothelial hyperplasia (IPEH), a lesion not previously reported in the urinary bladder of cattle, were also described. Bovine papillomavirus type-2 DNA was amplified in tumor samples. Forty vascular tumors were investigated by dual-labeling immunofluorescence, and, for the first time, a coexpression of E5 and platelet-derived growth factor β receptor (PDGFβR) was shown to occur. The results show that the BPV-2 E5 oncoprotein binds to the activated form of the PDGFβ receptor thus playing an important role in mesenchymal as well as epithelial carcinogenesis of the urinary bladder. Furthermore, these findings demonstrate that BPV-2 infects both epithelial and mesenchymal cells.

The E5 proteins

The E5 proteins are short transmembrane proteins encoded by many animal and human papillomaviruses. These proteins display transforming activity in cultured cells and animals, and they presumably also play a role in the productive virus life cycle. The E5 proteins are thought to act by modulating the activity of cellular proteins. Here, we describe the biological activities of the best-studied E5 proteins and discuss the evidence implicating specific protein targets and pathways in mediating these activities. The primary target of the 44-amino acid BPV1 E5 protein is the PDGF β receptor, whereas the EGF receptor appears to be an important target of the 83-amino acid HPV16 E5 protein. Both E5 proteins also bind to the vacuolar ATPase and affect MHC class I expression and cell-cell communication. Continued studies of the E5 proteins will elucidate important aspects of transmembrane protein-protein interactions, cellular signal transduction, cell biology, virus replication, and tumorigenesis.

Bovine papillomavirus type 2 infection and microscopic patterns of urothelial tumors of the urinary bladder in water buffaloes

Microscopic patterns of thirty-four urothelial tumors of the urinary bladder of water buffaloes from the Marmara and Black Sea Regions of Turkey are here described. All the animals grazed on lands rich in bracken fern. Histological diagnosis was assessed using morphological parameters recently suggested for the urinary bladder tumors of cattle. Papillary carcinoma was the most common neoplastic lesion (22/34) observed in this study, and low-grade carcinoma was more common (seventeen cases) than high-grade carcinoma (five cases). Papilloma, papillary urothelial neoplasm of low malignant potential (PUNLMP), and invasive carcinomas were less frequently seen. Carcinoma in situ (CIS) was often detected associated with some papillary and invasive carcinomas. De novo (primary) CIS was rare representing 3% of tumors of this series. A peculiar feature of the most urothelial tumors was the presence in the tumor stroma of immune cells anatomically organized in tertiary lymphoid organs (TLOs). Bovine papillomavirus type-2 (PV-2) E5 oncoprotein was detected by molecular and immunohistochemistry procedures. Early protein, E2, and late protein, L1, were also detected by immunohistochemical studies. Morphological and molecular findings show that BPV-2 infection contributes to the development of urothelial bladder carcinogenesis also in water buffaloes.

Comparison of two PCR strategies for the detection of bovine papillomavirus

Bovine papillomavirus (BPV) is a diverse group of double-stranded DNA oncogenic viruses, which have been detected in epithelial lesions and body fluids. Most studies of BPV infection rely on a single method for DNA detection; however the use of any single method or technique may underestimate the true prevalence of this virus. The purpose of this study was to compare two PCR strategies for the detection of BPV in skin lesions and fluids: these involve the use of BPV type-specific and consensus primers. Seventy-two cutaneous lesions, 57 blood samples and 59 semen samples were collected. PCR was used with the FAP consensus primers and BPV type-specific primers (for BPVs 2, 3, 4, 5, 8, 9 and 10), along with sequencing assays, to detect the BPV types. Phylogenetic analysis was carried out by means of the maximum likelihood method. It was found that both FAP and BPV type-specific primer sets could amplify BPV types of DNA in skin lesions, blood and semen samples. However, the BPV type-specific primers were more sensitive than the consensus primers and were able to detect co-infection of BPV in the samples. The consensus primers amplified five BPV types and were more suitable for detecting new putative BPV types. Thus, account should be taken of both PCR primer systems to identify co-infection, the presence of novel viruses, and avoid false-negative results.

Productive infection of bovine papillomavirus type 2 in the urothelial cells of naturally occurring urinary bladder tumors in cattle and water buffaloes

Background

Papillomaviruses (PVs) are highly epitheliotropic as they usually establish productive infections within squamous epithelia of the skin, the anogenital tract and the oral cavity. In this study, early (E) and late (L) protein expression of bovine papillomavirus type 2 (BPV-2) in the urothelium of the urinary bladder is described in cows and water buffaloes suffering from naturally occurring papillomavirus-associated urothelial bladder tumors.

Methods and Findings

E5 protein, the major oncoprotein of the BPV-2, was detected in all tumors. L1 DNA was amplified by PCR, cloned and sequenced and confirmed to be L1 DNA. The major capsid protein, L1, believed to be only expressed in productive papillomavirus infection was detected by Western blot analysis. Immunohistochemical investigations confirmed the presence of L1 protein both in the cytoplasm and nuclei of cells of the neoplastic urothelium. Finally, the early protein E2, required for viral DNA replication and known to be a pivotal factor for both productive and persistent infection, was detected by Western blot and immunohistochemically. Electron microscopic investigations detected electron dense particles, the shape and size of which are consistent with submicroscopic features of viral particles, in nuclei of neoplastic urothelium.

Conclusion

This study shows that both active and productive infections by BPV-2 in the urothelium of the bovine and bubaline urinary bladder can occur in vivo.

Human papillomavirus vertical transmission: review of current data

Despite the increasing evidence of human papillomavirus (HPV) vertical transmission, this route is regarded as less clinically important because of the detections of transient HPV DNA. However, recent studies have provided clear evidence of papillomavirus productive infection in lymphocytes, placenta, and bovine fetal tissue. Furthermore, a model of papillomavirus latency has been recently proposed that could explain the failure or transience in HPV detection observed in some infected infants. This new evidence of hematogeneous and vertical spread of HPV suggests that these modes of transmission should be investigated in greater detail to obtain a better understanding of the infection and a fuller awareness of the preventive measures that can be taken against HPV-related diseases.

The presence and gene expression of bovine papillomavirus in the peripheral blood and semen of healthy horses

Papillomavirus (PV) are double-stranded DNA viruses that can cause both benignant and malignant tumours in mammals. Twelve genotypes of bovine papillomavirus (BPV1-12) have been identified so far. The presence of BPV1 and 2 has been found in the body fluids of cattle and horses. The aim of this study is to investigate the presence of BPV DNA and the expression of viral genes in the blood and sperm cells of healthy horses using PCR and RT-PCR. BPV-1 or 2 was detected in 14 of 70 blood samples (20%) and in 11 of 31 semen samples (35%). In five of fourteen blood samples, the E5 expression tested positive, while no blood sample was positive for L1 expression. Four of 11 (36%) semen cell samples proved to be positive for E5 expression, while no gene expression in L1 could be detected. This is the first study that shows BPV1 gene expression in the blood and semen of healthy horses. Our data illustrate the need for a better understanding of the presence of BPV in non-epithelial tissues of horses and their role in the vertical and horizontal transmission of these viruses.

Bovine papillomavirus type 2 infects the urinary bladder of water buffalo (Bubalus bubalis) and plays a crucial role in bubaline urothelial carcinogenesis

Bovine papillomavirus type 2 (BPV-2) has been shown to infect and play a role in urinary bladder carcinogenesis of buffaloes grazed on pastures with ferns from the Marmara and Black Sea Regions of Turkey. BPV-2 DNA has been found in both neoplastic and non-neoplastic lesions of the urinary bladder. Furthermore, this virus may be a normal inhabitant of the urinary bladder since BPV-2 DNA has also been detected in clinically normal buffaloes. The viral activation by fern immunosuppressant or carcinogen may trigger the urothelial cell transformation. The E5 oncoprotein was solely detected in urothelial tumours and appeared to be co-localized with the overexpressed and phosphorylated platelet derived growth factor (PDGF) β receptor in a double-colour immunofluorescence assay. Our results indicate that the E5-PDGF β receptor interaction also occurs in spontaneous tumours of the bubaline urinary bladder, revealing an additional role of BPV-2 in bladder carcinogenesis of buffaloes.

Bacterial isolates from the urine of cattle affected by urothelial tumors of the urinary bladder

Microbiological investigations were performed on urine samples from 108 cows affected by urothelial tumors of the urinary bladder. Bacteria, frequently of mixed population, were isolated from 100 animals. Gram-positive bacteria prevailed, with Staphylococcus spp. and Bacillus spp. being the most common. Escherichia coli and Acinetobacter spp. were the most frequently recovered Gram-negative bacteria. E5 oncoprotein was detected in 86 of the 108 urothelial tumors under study. In the majority of cases, bacterial agents and BPV-2 E5 were simultaneously detected. A marked down-regulation of Tamm-Horsfall protein was also observed in the examined cases. In addition, the p65 subunit of the nuclear factor-κB (NF-κB) transcription factor appeared to be overexpressed. In all cases, a mild to severe chronic inflammation was evident in the stroma of urinary bladder tumors. Bacterial components may play a role in the activation of the NF-κB and might cause chronic inflammation resulting in an impaired ability to clear BPV-2 infection, thus cooperating with the virus in cancer development. As in man, therefore, bacteria could play both a direct and an indirect role in bovine bladder carcinogenesis.

Productive infection of bovine papillomavirus type 2 in the placenta of pregnant cows affected with urinary bladder tumors

Papillomaviruses (PVs) are believed to be highly epitheliotropic as they usually establish productive infections within stratified epithelia. In vitro, various PVs appear to complete their entire life-cycle in different trophoblastic cell lines. In this study, infection by and protein expression of bovine papillomavirus type 2 (BPV-2) in the uterine and chorionic epithelium of the placenta has been described in four cows suffering from naturally occurring papillomavirus-associated urothelial bladder tumors. E5 oncoprotein was detected both by Western blot analysis and immunohistochemically. It appears to be complexed and perfectly co-localized with the activated platelet-derived growth factor ß receptor (PDGFßR) by laser scanning confocal microscopy. The activated PDGFßR might be involved in organogenesis and neo-angiogenesis rather than in cell transformation during pregnancy. The major capsid protein, L1, believed to be only expressed in productive papillomavirus infection has been detected by Western blot analysis. Immunohistochemical investigations confirmed the presence of L1 protein both in the cytoplasm and nuclei of cells of the uterine and chorionic epithelium. Trophoblastic cells appear to be the major target for L1 protein expression. Finally, the early protein E2, required for viral DNA replication and known to be expressed during a productive infection, has been detected by Western blot and immunohistochemically. Electron microscopic investigations detected viral particles in nuclei of uterine and chorionic epithelium. This study shows that both active and productive infections by BPV-2 in the placenta of pregnant cows can occur in vivo.

The RBP-Jκ binding sites within the RTA promoter regulate KSHV latent infection and cell proliferation

Kaposi's sarcoma-associated herpesvirus (KSHV) is tightly linked to at least two lymphoproliferative disorders, primary effusion lymphoma (PEL) and multicentric Castleman's disease (MCD). However, the development of KSHV-mediated lymphoproliferative disease is not fully understood. Here, we generated two recombinant KSHV viruses deleted for the first RBP-Jκ binding site (RTA_1st) and all three RBP-Jκ binding sites (RTA_all) within the RTA promoter. Our results showed that RTA_1st and RTA_all recombinant viruses possess increased viral latency and a decreased capability for lytic replication in HEK 293 cells, enhancing colony formation and proliferation of infected cells. Furthermore, recombinant RTA_1st and RTA_all viruses showed greater infectivity in human peripheral blood mononuclear cells (PBMCs) relative to wt KSHV. Interestingly, KSHV BAC36 wt, RTA_1st and RTA_all recombinant viruses infected both T and B cells and all three viruses efficiently infected T and B cells in a time-dependent manner early after infection. Also, the capability of both RTA_1st and RTA_all recombinant viruses to infect CD19+ B cells was significantly enhanced. Surprisingly, RTA_1st and RTA_all recombinant viruses showed greater infectivity for CD3+ T cells up to 7 days. Furthermore, studies in Telomerase-immortalized human umbilical vein endothelial (TIVE) cells infected with KSHV corroborated our data that RTA_1st and RTA_all recombinant viruses have enhanced ability to persist in latently infected cells with increased proliferation. These recombinant viruses now provide a model to explore early stages of primary infection in human PBMCs and development of KSHV-associated lymphoproliferative diseases.

Kaposi's sarcoma-associated herpesvirus (KSHV) is tightly linked to at least two lymphoproliferative disorders, primary effusion lymphoma (PEL) and multicentric Castleman's disease (MCD). The life cycle of KSHV consists of latent and lytic phase. RTA is the master switch for viral lytic replication. In this study, we first show that recombinant viruses deleted for the RBP-Jκ sites within the RTA promoter have a decreased capability for lytic replication, and thus enhanced colony formation and proliferation of infected cells. Interestingly, the recombinant viruses show greater infectivity in human peripheral blood mononuclear cells (PBMCs). The recombinant viruses also infected CD19+ B cells and CD3+ T cells with increased efficiency in a time-dependent manner and now provide a model which can be used to explore the early stages of primary infection in human PBMCs, as well as the development of KSHV-associated lymphoproliferative diseases.

Inoculation of young horses with bovine papillomavirus type 1 virions leads to early infection of PBMCs prior to pseudo-sarcoid formation

Bovine papillomavirus types 1 and 2 (BPV-1 and BPV-2) are known to induce common equine skin tumours, termed sarcoids. Recently, it was demonstrated that vaccination with BPV-1 virus-like particles (VLPs) is safe and highly immunogenic in horses. To establish a BPV-1 challenge model for evaluation of the protective potential of BPV-1 VLPs, four foals were injected intradermally with infectious BPV-1 virions and with viral genome-based and control inocula, and monitored daily for tumour development. Blood was taken before inoculation and at weekly intervals. BPV-1-specific serum antibodies were detected by a pseudo-virion neutralization assay. Total nucleic acids extracted from tumours, intact skin and PBMCs were tested for the presence of BPV-1 DNA and mRNA using PCR and RT-PCR, respectively. Intralesional E5 oncoprotein expression was determined by immunofluorescence. Pseudo-sarcoids developed exclusively at sites inoculated with virions. Tumours became palpable 11-32 days after virion challenge, reached a size of ≤20 mm in diameter and then resolved in ≤6 months. No neutralizing anti-BPV-1 serum antibodies were detectable pre- or post-challenge. BPV-1 DNA was present in lesions but not in intact skin. In PBMCs, viral DNA was already detectable before lesions were first palpable, in concentrations correlating directly with tumour growth kinetics. PBMCs from two of two foals also harboured E5 mRNA. Immunofluorescence revealed the presence of the E5 protein in tumour fibroblasts, but not in the apparently normal epidermis overlying the lesions. Together with previous findings obtained in horses and cows, these data suggest that papillomavirus infection may include a viraemic phase.