Bovine Papillomavirus Infection Research Articles

Vertical Intrauterine Bovine and Ovine Papillomavirus Coinfection in Pregnant Cows.

There is very little information available about transplacental infections by the papillomavirus in ruminants. However, recent evidence has emerged of the first report of vertical infections of bovine papillomavirus (BPV) in fetuses from naturally infected, pregnant cows. This study reports the coinfection of BPV and ovine papillomavirus (OaPV) in bovine fetuses from infected pregnant cows suffering from bladder tumors caused by simultaneous, persistent viral infections. Some molecular mechanisms involving the binary complex composed of Eras and platelet-derived growth factor β receptor (PDGFβR), by which BPVs and OaPVs contribute to reproductive disorders, have been investigated. A droplet digital polymerase chain reaction (ddPCR) was used to detect and quantify the nucleic acids of the BPVs of the Deltapapillomavirus genus (BPV1, BPV2, BPV13, and BPV14) and OaPVs belonging to the Deltapapillomavirus (OaPV1, OaPV2, and OaPV4) and Dyokappapapillomavirus (OaPV3) genera in the placenta and fetal organs (heart, lung, liver, and kidneys) of four bovine fetuses from four pregnant cows with neoplasia of the urinary bladder. A papillomaviral evaluation was also performed on the bladder tumors and peripheral blood of these pregnant cows. In all fetal and maternal samples, the genotype distribution of BPVs and OaPVs were evaluated using both their DNA and RNA. A BPV and OaPV coinfection was seen in bladder tumors, whereas only BPV infection was found in peripheral blood. The genotype distribution of both the BPVs and OaPVs detected in placentas and fetal organs indicated a stronger concordance with the viral genotypes detected in bladder tumors rather than in peripheral blood. This suggests that the viruses found in placentas and fetuses may have originated from infected bladders. Our study highlights the likelihood of vertical infections with BPVs and OaPVs and emphasizes the importance of gaining further insights into the mechanisms and consequences of this exposure. This study warrants further research as adverse pregnancy outcomes are a major source of economic losses in cattle breeding.

Comparative structural studies on Bovine papillomavirus E6 oncoproteins: Novel insights into viral infection and cell transformation from homology modeling and molecular dynamics simulations.

Bovine papillomavirus (BPV) infects cattle cells worldwide, leading to hyperproliferative lesions and the potential development of cancer, driven by E5, E6, and E7 oncoproteins along with other cofactors. E6 oncoprotein binds experimentally to various proteins, primarily paxillin and MAML1, as well as hMCM7 and CBP/p300. However, the molecular and structural mechanisms underlying BPV-induced malignant transformation remain unclear. Therefore, we have modeled the E6 oncoprotein structure from non-oncogenic BPV-5 and compared them with oncogenic BPV-1 to assess the relationship between structural features and oncogenic potential. Our analysis elucidated crucial structural aspects of E6, highlighting both conserved elements across genotypes and genotype-specific variations potentially implicated in the oncogenic process, particularly concerning primary target interactions. Additionally, we predicted the location of the hMCM7 binding site on the N-terminal of BPV-5 E6. This study enhances our understanding of the structural characteristics of BPV E6 oncoproteins and their interactions with host proteins, clarifying structural differences and similarities between high and low-risk BPVs. This is important to understand better the mechanisms involved in cell transformation in BPV infection, which could be used as a possible target for therapy.

Phylogeny and amino acid analysis in single and mixed bovine papillomavirus infections in Southern Brazil, 2016-2020.

Bovine papillomaviruses (BPVs) exhibit a high degree of genetic variability, and several viral types have been identified based on analysis of the L1 gene. The L1 is the main capsid protein and the main target for neutralizing antibodies. We performed a retrospective study onBPVscirculating in Rio Grande do Sul state, Southern Brazil, in 2016-2020. DNA from 43 bovine papilloma samples were amplified using two degenerate primer sets - FAP59/64 and MY09/11 - targeting the L1 region, and analyzed for phylogeny, mixed BPV infections(coinfections) and amino acid (aa) sequences. We also performed an in silico analysis with 114 BPV L1 sequences from the GenBank database to assess the agreement between the phylogeny obtained based on complete L1 sequences versus that based on the region amplified using the FAP59/64 and MY09/11 primer sets. Considering single and coinfections, we identified 31 BPV-1 (31/43; 72.1%), 27 BPV-2 (27/43; 62.8%) and 4 BPV-6 (4/43; 9.3%). Coinfections with BPV-1 and BPV-2 were observed in 61.3% of the samples. Our results are supported by in silico analyses that demonstrate that the classification usingFAP59/64 or MY09/11 matches the complete L1 results, except for BPV-17 and -18, which may be mistakenly classified depending on the primers used. Furthermore, we found unique or rare amino acids in at least one L1 sequence of each BPV type identified in our study, some of which have been identified previously in papillomavirus epitopes, suggesting immune-mediated selection. Finally,our study provides an overview of BPVscirculatingin Southern Brazil over the last five years and point to the combined use of primers FAP59/64 and MY09/11 for analysis of BPV coinfections and putative epitopes.

Expression of Cell-Cycle Regulatory Proteins pRb, Cyclin D1, and p53 Is Not Associated with Recurrence Rates of Equine Sarcoids.

Simple SummaryExpression of cell-cycle regulatory proteins pRB, Cyclin D1, and p53 is not associated with recurrence rates of equine sarcoids. Sarcoids are common tumors of equids, and since the pathogenesis and Bovine Papillomavirus (BPV) mechanism of tumorigenesis is not fully understood yet, we investigated the expression of cell cycle regulatory proteins pRB, Cyclin D1, and p53 to understand whether BPV and Human Papillomavirus (HPV) share similar mechanisms of action. The expression pattern of these proteins in a series of BPV-positive equine sarcoids is different from HPV-induced tumors. Moreover, their expression is not correlated with the recurrence or occurrence of sarcoids in new body sites.Sarcoids are among the most common tumors diagnosed in equids; their association with bovine papillomaviruses (BPV) infection has been widely reported, but the mechanism of carcinogenesis has not been fully elucidated. To verify whether BPV infection causes dysregulation of the pRb-Cyclin D1-p16CDKN2A-p53 pathway as reported for human papillomavirus (HPV), the study employed immunohistochemistry to test 55 equine sarcoid biopsies for the expression of pRb, Cyclin D1, and p53 cell cycle regulatory proteins and to evaluate the proliferative rate through Ki67. High Cyclin D1 and pRb expression were observed in 51% and 80% of cases, respectively, while low expression was observed in 49% and 20% of cases, respectively. Significantly higher Ki67 proliferation indexes were observed in fibroblastic, nodular, and mixed sarcoids compared to the occult and verrucous. High proliferation was significantly associated with high Cyclin D1 expression. In contrast with previous studies, p53 positivity was not observed in the cases examined in this study. Moreover, follow-up analysis revealed that fibroblastic, mixed sarcoids were associated with significantly higher local recurrence rates while the verrucous subtype was associated with higher rates of new sarcoid development at distant sites.

Comparative Pathologic, Immunohistochemical, Ultrastructural and Molecular study of Bovine Papilloma Virus type 1 E5 Oncogene infection in Exotic and Indigenous cattle breeds

Bovine papillomavirus (BPV) induces benign tumors of cutaneous or mucosa epithelia, called papillomas or warts in cattle and generally regress without eliciting any serious clinical problems in the host, but occasionally persist and provide the focus for malignant transformation to squamous cell carcinoma. This has a negative implication in beef and hide industry. There is paucity of information on the comparative pathology and molecular detection of BPVs in different breeds of nomadic cattle. Consequently, 340 nomadic cattle grazing in Plateau state Nigeria were screened clinically for papillomatosis followed by histopathology. Lesion consistent with papillomatosis were further investigated using immunohistochemistry (IHC), Polymerase chain reaction (PCR) and electron microscopy. Twenty cattle (0.06%) of Friesian, Zebu, Muturu and White Fulani breeds had cutaneous papilloma and skin lesions of the head, neck, shoulders, legs, dorsum, lower abdomen and scrotum. However, only 16 (0.05%) cattle skin biopsy samples were consistent with papillomatosis histopathologically revealing varying degrees of hyperplastic epidermis with acanthosis and orthokeratotic hyperkeratosis. Nuclei in the granular layer of the epidermis were IHC positive for Bovine papillomavirus type I antigen while skin biopsy was BPV-1 E5 oncoprotein gene positive by PCR. Electron microscopy revealed ultrastructural changes consistent with Bovine papillomavirus infection. The distribution and severity of lesion varied in different breeds of nomadic cattle. The detection, diagnosis and characterization of papillomavirus in these cattle enabled the development of autogenous vaccine to immunized cattle. This study highlighted the comparative pathology and molecular characterization of BPVs in different breeds of nomadic cattle, which hitherto was lacking.

Association Between BoLA-DRB3.2 Polymorphism and Bovine Papillomavirus Infection for Bladder Tumor Risk in Podolica Cattle.

Blood samples from 260 unrelated cattle (132 animals affected by papillomavirus-associated bladder tumors and 128 healthy) were genotyped using the classic polymerase chain reaction/restriction fragment length polymorphism method to screen MHC class II bovine leukocyte antigen-DRB3. 2 polymorphism. The DRB3*22 allele was significantly (p ≤ 0.01) detected in healthy cattle, thus appearing to have a negative association (protective effect) with virus infection of the urinary bladder known to represent a bladder tumor risk for cattle living free at pasture. Considering the two sequence alleles identified in animals carrying DRB3*22, DRB3*011:01 allele from samples of animals harboring the unexpressed bovine papillomaviruses (BPV)-2 E5 gene was characterized by amino acid residues believed to have a protective effect against BPV infection such as arginine at position 71 (R71) in pocket 4, histidine at position 11 (H11) in pocket 6, and both glutamine at position 9 (Q9) and serine at position 57 (S57) in pocket 9 of the antigen-binding groove. The DRB3*011:02v allele from affected animals was characterized by amino acids believed to be susceptibility residues such as lysine (K71), tyrosine (Y11), glutamic acid (E9), and aspartic acid (D57) in these pockets. These results suggest that animals harboring the DRB3*011:01 allele may have a lower risk of BPV infection and, consequently, a reduced risk of bladder tumors.

Electron microscopy and phylogenetic analysis of Bovine papillomavirus infection in cattle from four Egyptian governorates.

Cutaneous warts are the common clinical feature of infection with Bovine papillomavirus (BPV), and it is commonly known as bovine papillomatosis. It causes significant economic losses, especially in the dairy sector. The aim of this study was surveillance of the circulating strains of BPV in four Egyptian governorates and characterization by electron microscopy. Warts skin lesions and whole blood from seventy-eight native breed cattle were obtained. Molecular detection using two different sets of primers, phylogenetic analysis, and electron microscopy were carried out. The obtained results showed that using FAP59/FAP64 primer set is more sensitive than the MY09/My11 primer set in the detection of the papilloma L1 gene either in the blood or in the skin lesion. Sequence analysis of the partially amplified L1 gene revealed 4 different strains belonging to Deltapapillomavirus 4. Only Alfayoum_Deltapapillomavirus_2018 (accession no: MW018705) was found to be closely related to the strain previously isolated in different Egyptian governorates in 2017, and 2 strains were closely related to an isolate of equine origin. Electron microscopy examination of the skin lesions showed the presence of negatively stained rounded, non-enveloped virus particles with a size of 60 nm in diameter. In conclusion, continuous surveillance and characterization of the circulating strains using multiple sets of primers are important. Efficient biosecurity measures must be applied to decrease transmission of papillomavirus between the different animal species, especially in the mixed management system.

Equine Sarcoids-Causes, Molecular Changes, and Clinicopathologic Features: A Review.

Equine sarcoid is the most common skin tumor of horses. Clinically, it occurs as a locally invasive, fibroblastic, wart-like lesion of equine skin, which has 6 clinical classes: occult, verrucose, nodular, fibroblastic, mixed, and malignant. Sarcoids may be single but multiple lesions are more frequent. The typical histological feature is increased density of dermal fibroblasts which form interlacing bundles and whorls within the dermis. Lesions are mostly persistent, resist therapy, and tend to recur following treatment. In general, sarcoids are not fatal but their location, size, and progression to the more aggressive form may lead to the withdrawal of a horse from use and serious infringement of their welfare leading to the loss of valuable animals. Bovine papillomavirus (BPV) type 1 and less commonly type 2 contribute to the development of equine sarcoid. The viral genome and proteins are detected in a high percentage of cases. Furthermore, viral oncoprotein activity leads to changes in the fibroblastic tissue similar to changes seen in other types of tumors. Equine sarcoids are characterized by a loss of tumor suppressor activity and changes allowing abnormal formation of the affected tissue, as well as y immune defense abnormalities that weaken the host's immune response. This impaired immune response to BPV infection appears to be crucial for the development of lesions that do not spontaneously regress, as occurs in BPV-infected cows.

Congenital cutaneous fibropapillomatosis without evidences of papillomavirus infection in a Holstein-Friesian calf.

A male Holstein-Friesian calf was born with multiple, cauliflower-like, pale pink cutaneous masses on the head and limbs. On histopathological examination, the cutaneous masses were diagnosed as congenital cutaneous fibropapillomatosis. Those lesions involved focal proliferation of sebaceous gland in the dermis. There were no histological findings to suggest bovine papillomavirus infection, such as the presence of intranuclear inclusion bodies, large keratohyalin granules, and koilocytosis. Furthermore, papillomaviral antigens and DNA were not detected by immunohistochemistry and polymerase chain reaction, respectively. These results suggested that there was no association between these cutaneous lesions and bovine papillomavirus infection, and the lesions were considered as harmartomatous changes.

Molecular detection and genetic diversity of bovine papillomavirus in dairy cows in Xinjiang, China.

BackgroundBovine papillomatosis is a type of proliferative tumor disease of skin and mucosae caused by bovine papillomavirus (BPV). As a transboundary and emerging disease in cattle, it poses a potential threat to the dairy industry.ObjectivesThe aim of this study is to detect and clarify the genetic diversity of BPV circulating in dairy cows in Xinjiang, China.Methods122 papilloma skin lesions from 8 intensive dairy farms located in different regions of Xinjiang, China were detected by polymerase chain reaction. The genetic evolution relationships of various types of BPVs were analyzed by examining this phylogenetic tree.ResultsTen genotypes of BPV (BPV1, BPV2, BPV3, BPV6, BPV7, BPV8, BPV10, BPV11, BPV13, and BPV14) were detected and identified in dairy cows. These were the first reported detections of BPV13 and BPV14 in Xinjiang, Mixed infections were detected, and there were geographical differences in the distribution of the BPV genotypes. Notably, the BPV infection rate among young cattle (< 1-year-old) developed from the same supply of frozen sperm was higher than that of the other young cows naturally raised under the same environmental conditions.ConclusionsGenotyping based on the L1 gene of BPV showed that BPVs circulating in Xinjiang China displayed substantial genetic diversity. This study provided valuable data at the molecular epidemiology level, which is conducive to developing deep insights into the genetic diversity and pathogenic characteristics of BPVs in dairy cows.

Molecular Characterization and Developing a Point-of-Need Molecular Test for Diagnosis of Bovine Papillomavirus (BPV) Type 1 in Cattle from Egypt.

Simple SummaryBovine papillomatosis is a disease caused by bovine papillomavirus (BPV), which is a diverse group of oncogenic viruses that challenge cattle industry, resulting in significant economic losses. The present study investigated the occurrence of bovine papillomatosis among cattle (n = 308) with cutaneous warts on the head and neck from New valley Province, Egypt through molecular detection of BPV-1, -2, -4, -5, and -10. The work also involved a phylogenetic analysis of the positive samples for detection of the genetic relatedness of the virus. Interestingly, BPV-1 DNA was detected in 84.6% of the collected samples. Furthermore, the study included the development of an isothermal nucleic acid amplification test, which is a field test combining molecular and lateral flow immunoassays for point-of-need testing appropriate for veterinary use in resource-limited settings. Collectively, our study provided interesting data related to the combined use of molecular and immunoassays methods in the detection of the virus besides better understanding the genetic relatedness of the circulating genotypes of BPV-1 in Egypt. Our study suggested further research to explore more about the other genotypes of BPV in the Egyptian environment that could be helpful for the implementation of control strategies for combating this disease.Bovine papillomatosis is a viral disease of cattle causing cutaneous warts. A diagnosis of this viral infection is very mandatory for combating the resulting economic losses. Given the limited data available about bovine papillomavirus (BPV) in Egypt, the present study involved the molecular diagnosis of bovine papillomavirus type-1 (BPV-1), -2, -4, -5, and -10 in cattle presenting cutaneous warts on the head and neck from New Valley Province, Egypt. The phylogenetic analysis of the detected types of BPV was also performed, followed by developing a point-of-need molecular assay for the rapid identification of identified BPV types. In this regard, a total of 308 cattle from private farms in Egypt were clinically examined, of which 13 animals presented cutaneous warts due to suspected BPV infection. The symptomatic animals were treated surgically, and biopsies from skin lesions were collected for BPV-1, -2, -4, -5, and -10 molecular identification using polymerase chain reaction (PCR). The presence of BPV-1 DNA was confirmed in 11 collected samples (84.6%), while BPV-2, -4, -5, and -10 were not detected. Sequencing of the PCR products suggested the Egyptian virus is closely related to BPV found in India. An isothermal nucleic acid amplification test (NAAT) with labeled primers specific for the BPV-1 L1 gene sequence, and based on recombinase polymerase amplification (RPA), in combination with a lateral flow strip assay for the detection of RPA products, was developed and tested. The point-of-need molecular assay demonstrated a diagnostic utility comparable to PCR-based testing. Taken together, the present study provides interesting molecular data related to the occurrence of BPV-1 in Egypt and reveals the genetic relatedness of the Egyptian BPV-1 with BPV-1 found in buffalo in India. In addition, a simple, low-cost combined test was also validated for diagnosis of the infection. The present study suggests the necessity of future investigations about the circulating strains of the virus among the cattle in Egypt to assess their genetic relatedness and better understand the epidemiological pattern of the disease.

&lt;p&gt;Pathological studies on &lt;em&gt;Pteris cretica&lt;/em&gt; (L.) fern-Bovine Papilloma Virus infection in Syrian Golden Hamsters (&lt;em&gt;Mesocricetus auratus&lt;/em&gt;)&lt;/p&gt;

Pteris cretica (L.) commonly known as Cretan brake is widely distributed in nature and considered as potential environmental carcinogen. However, only limited literature is available on this fern commonly taken by cattle while grazing. It is known that in cattle Bovine papilloma virus (BPV) induced benign tumours are converted into malignant with interaction of ptaquiloside (Pta) present in ferns. In the present investigation, we evaluated the pathological effects of P. cretica (PC)-BPV infection in laboratory model hamster. Though toxic principle Pta was detected in fern samples but quercetin could not be found. Tumours were successfully induced in hamsters by cutaneous wart suspension and histopathologically diagnosed as fibroma and lipofibroma. Histopathologically, hamsters showed mild to moderate vascular changes in vital organs, multiple cysts, degenerative changes, bile duct hyperplasia and necrosis in liver, haemorrhages and haemosiderosis in spleen, hypersecretory activity and prominent Peyer’s patches in ileum, degenerative changes and presence of eosinophilic casts in renal tubules. Ultrastructural study revealed apoptosis in hepatocytes, abundance of variable shaped mitochondria in renal tubular lining epithelial cells and enterocytes showed abundance of mitochondria and cytoplasmolysis in the fern fed groups. Almost all the hamsters from BPV, fern and virus infection (PC+BPV) groups developed similar type of tumorous growths. The visible growths in the hamsters of these groups were either single or double large sized except multiple tumorous growths in one hamster from PC+BPV group. However, multiple palpable subcutaneous nodules were developed at the site of scarification in all the hamsters of BPV and PC+BPV groups. Our findings suggest that the Pta containing P. cretica feeding induced hepatotoxic and nephrotoxic lesions in hamsters, but effects of P. cretica -BPV infection were found negligible.

Prohibitin 2 is Involved in Parkin-Mediated Mitophagy in Urothelial Cells of Cattle Infected with Bovine Papillomavirus.

Prohibitin 2 (PHB2), an inner mitochondrial membrane (IMM) protein, has recently been identified as a novel receptor involved in parkin-mediated mitophagy. In the field of veterinary medicine, the role of PHB2 in parkin-mediated mitophagy was described, for the first time, in urothelial cells of cattle, naturally infected with bovine papillomavirus (BPV). The BPV2 and BPV13 E5 oncoprotein, responsible for abortive infections in urothelial cells, was detected by RT-PCR. Severe ultrastructural abnormalities of the inner mitochondrial membrane were detected using transmission electron microscopy. PHB2 formed a functional complex with PHB1. PHB2 was significantly overexpressed in mitochondrial fractions from urothelial mucosa samples taken from cattle harbouring BPV infection. PHB2 overexpression could be attributed to mitochondrial dysfunction, as its expression levels in the cytosolic, microsomal, and nuclear fractions were seen to be unmodified. Immunoprecipitation studies revealed the interaction between PHB2 and phosphorylated forms of both PINK1 and parkin. Furthermore, PHB2 interacted with LC3-II, a marker of autophagosomal membranes and autophagy receptors, such as p62 and optineurin. PHB2 was shown to interact with transcription factor EB (TFEB), which is activated following parkin-mediated mitophagy, and embryonic stem cell-expressed Ras (ERAS), a constitutive protein coded by ERas. Western blot analysis revealed a significant overexpression of unphosphorylated TFEB in mitochondrial and nuclear fractions from urothelial mucosa samples from cattle suffering from BPV infection. Finally, PHB2 interacted with ERAS, believed to be involved in mitophagosome maturation. Taken together, the molecular and ultrastructural findings of this study suggested that BPV infection is responsible for parkin-dependent mitophagy, in the pathway of which PHB2 plays a crucial role.

Morphometric and Vascular Analyses and MMP-2 Expression in Bladders of Animals with Bovine Enzootic Haematuria

Background: Bovine enzootic haematuria is a chronic, non-infectious disease caused by the ingestion of bracken Pteridium aquilinum that contain ptaquiloside, substance responsible for the development of neoplasms in combination with bovine papillomavirus infection. Studies examining metalloproteinases have shown that these enzymes may be useful as prognostic markers and many studies have correlated the intratumoural microvessel density and incidence of metastasis in a variety of cancers, including bladder cancer. This study aimed to evaluate the urothelial morphology and vasculature and quantify the expression of the enzyme metalloproteinase-2 in the bladder lesions of bovine with enzootic haematuria.Materials, Methods &amp; Results: Forty bladders with macroscopic lesions were subjected to routine histological processing. The material was stained using the Hematoxylin-Eosin (HE) and Weigert's resorcin-fuchsin staining methods. The morphometric analysis included the measurement of the total thickness of the urothelium. Microscopically, the lesions were differentiated as neoplastic or non-neoplastic, and the vascular changes were characterised as vascular proliferation, ectasia, dilation and thickening and the material stained using the Weigert's resorcin-fuchsin method was used to evaluate sclerosis and the vascular fibroelastosis. The metalloproteinase expression was evaluated using an anti-metalloproteinase-2 antibody. The main non-neoplastic lesions found in the urothelium included clear cell metaplasia, dysplasia, hyperplasia, haemorrhage, cystitis cystica and Brunn's nests and the neoplastic lesions were haemangioma, myxoma, transitional cell carcinoma, adenocarcinoma, in situ carcinoma and haemangiosarcoma. The urothelium measurements revealed differences between the epithelial thicknesses of bladders with and without neoplasms. The bladder vasculature evaluation revealed the frequent occurrence of different pathological aspects, such as vascular proliferation, dilation, expansion, ectasia and thickening; more severe vascular proliferation, thickening and fibroelastosis were observed in bladders with neoplasms. Metalloproteinase-2 expression was observed in the epithelial cells, fibroblasts, endothelial cells and smooth muscle cells present in the tumour tissue and was a significant increase in the expression of MMP-2 in the neoplasms of mesenchymal origin compared to the neoplasms of epithelial origin.Discussion: The presence of a large variety of non-neoplastic lesions indicates the possibility that there are other factors concomitant to BEH involved. Epithelial hyperplasia and metaplasia, for example, could be the result of damage caused by bovine papillomavirus type 2 or even an altered urine pH. Furthermore, it is believed that the bladder has the capacity to generate various types of neoplasms due to the different histological components of the bladder, thus enabling it to generate both mesenchymal and epithelial lesions. The thickness of the urothelium was greater in all the quadrants with neoplasms compared to the quadrants without neoplasms. These data revealed that it is possible to use less invasive diagnostic imaging methods to characterise bovine enzootic haematuria and to measure tumour progression based on the severity of vascular changes. The vascular proliferation and thickening were significant in bladders with neoplasms, which may be explained by the fact that tumours require an extensive vascular supply. In addition, many tumours release vascular growth factors and promote neovascularisation. The intensity of the immunostaining of metalloproteinase-2 differed among the different types of neoplasms. However, due to the diversity of the tumours, it was not possible to establish a relationship between metalloproteinase-2 expression and tumour progression.

Mitophagy mediated by BNIP3 and BNIP3L/NIX in urothelial cells of the urinary bladder of cattle harbouring bovine papillomavirus infection

Autophagy is a powerful tool that host cells use to defend against viral infection. Mitophagy, the selective autophagic removal of dysfunctional mitochondria was upregulated in urothelial cancer cells harbouring bovine papillomavirus (BPV) infection, as detected by the expression of BPV E5 protein, the major oncoprotein of bovine Deltapapillomavirus genus. HIF-1α-induced mitophagy receptors, BNIP3 and BNIP3L/Nix, were found to be overexpressed in these cells. The BNIP3 and BNIP3L/Nix receptors were amplified, and amplicon sequencing showed homology between bovine BNPI3 and BNIP3L/Nix sequences deposited in GenBank (accession number: NM_001076366.1 and NM_001034614.2, respectively). The transcripts and protein levels of BNIP3 and BNIP3L/Nix were significantly overexpressed in hypoxic neoplastic cells relative to healthy, non-neoplastic cells. BNIP3 and BNIP3L/Nix interacted with the LC3 protein, a marker of autophagosome (mitophagosome) membrane, ERAS, a small GTPase, and p62, known to be a specific autophagy receptor protein, that plays a role in mitochondrial priming for mitophagy and subsequent elimination. ERAS also interacted with the BPV E5 oncoprotein at mitochondrial level. Furthermore, in anti-Bag3 mitochondrial immunoprecipitates, a complex composed of the Hsc70/Hsp70 chaperone, CHIP co-chaperone, Synpo2, ERAS, LC3, p62, BNPI3, and BNIP3L/Nix was also detected. 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 cargo, in association with its chaperone. ERAS may be involved in mitophagosome maturation via the PI3K signalling pathway. Ultrastructural findings revealed the presence of mitochondria exhibiting severe fragmentation and loss of cristae, as well as numerous mitochondria-containing autophagosomes.

Expression of the feline leukemia virus subgroup C receptors in normal and neoplastic urothelium of the urinary bladder of cattle associated with bovine papillomavirus infection

The feline leukemia virus subgroup C receptors (FLVCRs) were originally cloned as virus receptors, but are now believed to function also as heme transporters and are expressed in a broad range of tissues in a wide range of mammalian species. Expression of FLVCR1 and FLVCR2 was investigated in 19 bovine papillomavirus-associated urinary bladder cancers and in 15 non-neoplastic samples of bladder from cattle. E5 oncoprotein of bovine Deltapapillomaviruses (δPVs) was detected in 17 of the 19 bladder cancers. Flvcr1 and Flvcr2 were amplified and sequenced both in neoplastic and non-neoplastic samples showing a 100% identity with bovine Flvcr1 and Flvcr2 mRNA sequences present in GenBank database (accession numbers: NM_001206019.1 and NM_001192143.1, respectively). Reverse transcription (RT)-PCR showed that Flvcr1 and Flvcr2 were overexpressed in 4 and 5 out of 19 urothelial cancers, respectively, but in none of the non-neoplastic samples. In addition, western blot analysis detected higher levels of FLVCR1 and FLVCR2 in samples in which transcripts were not increased, suggesting post-translational changes to these proteins. Increased FLCVR1 and FLVCR2 was also observed immunohistochemically in the neoplastic cells. Immunolabeling for FLVCR1 was seen in the cytoplasm and plasm membrane of urothelial cancer cells, wheras immunolabeling for FLVCR2 was present within the nucleus. This is the first time that FLVCR expression has been investigated in bovine tissues and the first to suggest that expression could be increased in cancers. Additional studies are required to define the role, if any, of FLVCR in papillomavirus-associated cancer cells.

Bovine papilloma: aetiology, pathology, immunology, disease status, diagnosis, control, prevention and treatment: a review

Bovine papillomavirus (BPV) induces diseases of economic and veterinary importance leading to significant economic losses to livestock owners such as leather depreciation and mortality when it progresses to neoplasms. BPV affects the spinosum and granulosum layers of the skin causing warts. There are many reportage of BPV infection in domestic animals such as cattle, birds and wild animals such as tapir, giraffe, antelope and zebras. It also causes equine sarcoids in horses and donkeys. Gross lesions seen are mainly benign papillomas which most times regress but occasionally persist and progress to malignancy of the urinary bladder and upper alimentary tract leading to Enzootic haematuria. Equine sarcoids could be of the occult, nodular or verrucous types. Due to the ability to BPV to cause cancers, haematuria and skin pathologies, diagnosis of this infection has attracted huge interests. Diagnostic techniques include clinical examination, histopathology, polymerase chain reaction (PCR) Southern blot, dot blot, reverse blot, in situ hybridization and immunohistochemistry. All the aforementioned have been very helpful in the diagnosis of BPV. In conclusion, this review focused on the aetiology, viral structure pathogenicity, transmission, macroscopic and microscopic pathology, pathogenesis, immunology, gene products, prevention, treatment and control of this virus in affected animal species.

Bos taurus papillomavirus activity in peripheral blood mononuclear cells: demonstrating a productive infection.

Bovine papillomavirus (BPV) is an oncogenic virus with mucous and epithelial tropism. Possible productive virus infection in other tissues, such as blood, has been hypothesized. In order to investigate this possibility, three samples of skin papillomas and blood were collected from bovines with BPV infection and five samples of peripheral blood and one sample of normal tissue were collected from a calf without BPV infection. Peripheral blood mononuclear cells (PBMCs) were isolated from whole blood and examined by reverse transcription-polymerase chain reaction, immunofluorescence, in situ hybridization, and electron microscopy. The tissue samples were examined for histopathological and immunohistochemical features. The skin papillomas showed the presence of DNA sequences of BPV-2, BPV-11, and a putative virus type. The blood samples showed DNA sequences of BPV-1, 2, and 4 simultaneously. Immunohistochemistry showed BPV L1 protein in both epithelium and stroma and BPV E2 protein in koilocytes. In situ hybridization confirmed the presence of BPV DNA in PBMCs and immunofluorescence showed nuclear labeling of E2 and L1 BPV proteins in PBMCs. The transcription analysis revealed transcripts of BPV-1 L1, BPV-2 L2, and BPV-4 E7 in blood and papilloma samples of BPV-infected cattle. The comet assay revealed high levels of host cell DNA damage upon BPV infection. Electron microscopy analysis of PBMCs identified the presence of particles in the cytoplasm that are consistent with papillomavirus in size and shape. The productive infection of PBMCs with BPV has been previously discussed and this study provides evidence indicating that PBMCs are a target of BPV.

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.

Short Communication Development of a DNA-based vaccine strategy against bovine papillomavirus infection, involving the E5 or L2 gene

Papillomaviruses are known to cause tumor lesions, generally benign, in epithelial tissues of diverse organisms; these lesions may progress to cancer under suitable conditions. Bovine papillomavirus (BPV) can cause urinary bladder cancer and cancer of the upper gastrointestinal tract. Furthermore, BPV1 and BPV2 are implicated in the development of tumors in equids. Many studies with animal models clearly demonstrate that DNA vaccines are very effective tools in controlling viral infections, providing strong humoral and cellular immune responses. In this study, we have described the development of two vaccine constructs for the control of diseases caused by BPV. The 1st strategy is prophylactic and is based on the L2 gene; the 2nd is therapeutic and is based on the E5 gene. Vaccine constructs were obtained and evaluated in vitro in mammalian cells. The results show the occurrence of E5 and L2 transcription and viral protein production. These results confirm the functionality of the vaccine constructs in mammalian cells. This is the 1st step in the development of a DNA-based vaccine strategy for the control and/or treatment of diseases caused by BPV.