The VPS4 component of the ESCRT machinery plays an essential role in HPV infectious entry and capsid disassembly.

Human Papillomavirus (HPV) infection involves multiple steps, from cell attachment, through endocytic trafficking towards the trans-Golgi network, and, ultimately, the entry into the nucleus during mitosis. An essential viral protein in infectious entry is the minor capsid protein L2, which engages different components of the endocytic sorting machinery during this process. The ESCRT machinery is one such component that seems to play an important role in the early stages of infection. Here we have analysed the role of specific ESCRT components in HPV infection, and we find an essential role for VPS4. Loss of VPS4 blocks infection with multiple PV types, suggesting an evolutionarily conserved critical step in infectious entry. Intriguingly, both L1 and L2 can interact with VPS4, and appear to be in complex with VPS4 during the early stages of virus infection. By using cell lines stably expressing a dominant-negative mutant form of VPS4, we also show that loss of VPS4 ATPase activity results in a marked delay in capsid uncoating, resulting in a defect in the endocytic transport of incoming PsVs. These results demonstrate that the ESCRT machinery, and in particular VPS4, plays a critical role in the early stages of PV infection

Ciężka depresja z nasilonymi zaburzeniami funkcji poznawczych czy otępienie?

Bipolar affective disorder (BPAD) is a chronic mental disorder characterised by high recurrence. There are numerous manicor hypomanic episodes in the course of the disease. Making a correct diagnosis can be difficult as patients most oftenturn for help in the depression phase; they also tend to interpret the hypomania phase as a state of very good moodand increased creativity, not identifying it with the disease. A depressive episode in the course of BPAD is characterisedby the frequent coexistence of psychotic symptoms, excessive sleepiness and increased appetite. The first episode ofthe disease most often occurs at a young age. Apart from the typical symptoms of the depressive syndrome, we oftenobserve accompanying cognitive disorders, which represent a group of symptoms causing significant discomfort andsuffering to the patient. They most often intensify with the development of the disease and the number of subsequentepisodes. In particular, the effectiveness of attention processes, executive functions and memory is weakened. Thesedeficits have a negative impact on the patients’ day-to-day functioning at school, in the workplace and in society, andseverely impair it. The case report presented herein shows the difficulties in diagnosing severe cognitive disorders duringa depressive episode in the course of BPAD and the difficulties in differentiating between them and dementia, as wellas presents the effects of electroconvulsive therapy.Choroba afektywna dwubiegunowa (CHAD) jest przewlekłym zaburzeniem psychicznym charakteryzującym się dużą nawrotowością kolejnych, naprzemiennie pojawiających się epizodów maniakalnych (hipomaniakalnych) i depresyjnych. Postawienie prawidłowej diagnozy bywa trudne, ponieważ pacjenci zgłaszają się po pomoc najczęściej w fazie depresji, a fazę hipomanii interpretują jako stan bardzo dobrego samopoczucia, wzmożonej kreatywności, nie utożsamiając go z chorobą. Epizod depresyjny w przebiegu CHAD charakteryzuje się brakiem odpowiedzi na standardowo stosowane leki przeciwdepresyjne, częstym współistnieniem objawów psychotycznych, nadmierną sennością, wzmożonym apetytem. Pierwszy epizod choroby najczęściej pojawia się w młodym wieku. Poza typowymi objawami zespołu depresyjnego, towarzyszące im zaburzenia funkcji poznawczych są grupą objawów wywołujących u pacjenta znaczny dyskomfort i cierpienie. Najczęściej nasilają się one wraz z rozwojem choroby oraz z liczbą pojawiających się kolejnych epizodów. Osłabieniu ulega przede wszystkim efektywność procesów uwagi, funkcji wykonawczych oraz pamięci. Deficyty te w negatywny sposób oddziałują na codzienne funkcjonowanie szkolne, zawodowe oraz społeczne chorych, w znacznym stopniu je upośledzając. Przedstawiony przez nas opis przypadku ukazuje trudności w rozpoznawaniu nasilonych zaburzeń funkcji poznawczych w epizodzie depresyjnym w przebiegu CHAD oraz trudności w różnicowaniu z ich z otępieniem oraz przedstawia efekty zastosowanego leczenia elektrowstrząsami

Papillomaviruses and Endocytic Trafficking

Endocytic trafficking plays a major role in transport of incoming human papillomavirus (HPVs) from plasma membrane to the trans Golgi network (TGN) and ultimately into the nucleus. During this infectious entry, several cellular sorting factors are recruited by the viral capsid protein L2, which plays a critical role in ensuring successful transport of the L2/viral DNA complex to the nucleus. Later in the infection cycle, two viral oncoproteins, E5 and E6, have also been shown to modulate different aspects of endocytic transport pathways. In this review, we highlight how HPV makes use of and perturbs normal endocytic transport pathways, firstly to achieve infectious virus entry, secondly to produce productive infection and the completion of the viral life cycle and, finally, on rare occasions, to bring about the development of malignancy

HPV-16 virions can remain infectious for 2 weeks on senescent cells but require cell cycle re-activation to allow virus entry

Abstract Successful infection with Human Papillomaviruses requires mitosis, when incoming viral genomes gain access to nuclear components. However, very little is known about how long HPV particles can remain infectious in non-dividing cells or in which cellular compartments these viruses may reside. To investigate these questions we have used BJ cells as a reversible model of senescence and show that HPV-16 can only infect early-passage proliferating cells. Late-passage senescent cells are resistant to HPV infection, but this can be reversed by inducing cell cycle re-entry with a p53 siRNA. In senescent cells we find that efficient virus entry can be attained upon cell cycle re-entry 16 days after infection, demonstrating that HPV can persist for 2 weeks prior to induction of mitosis. However, exposing cells to anti-HPV-16 L1 neutralising antibody blocks infection at these late time points, suggesting that the virions reside near the cell surface. Indeed, immunofluorescence analysis shows that virions accumulate on the cell surface of senescent cells and only enter endocytic vesicles upon stimulation with p53 siRNA. These results demonstrate that HPV-16 virions can remain viable on a non-dividing cell for extended periods of time, but are nonetheless vulnerable to antibody-induced neutralisation throughout

Identification and characterisation of novel potential phospho-acceptor sites in HPV-16 E7

Several studies have described functional regulation of high-risk human papillomaviruses (HPVs), E6 and E7 oncoproteins via posttranslational modifications (PTMs). However, how these PTMs modulate the activity of E6 and E7, particularly in their targeting of cellular proteins, is not completely understood. In this study, we show that HPV16 E7 can be phosphorylated by casein kinase I (CKI) and glycogen synthase kinase 3 (GSK3). This principal phosphorylation occurs at threonine residues 5 and 7 with a more minor role for residues 19–20 in the N-terminal region of 16 E7. Intriguingly, whilst mutational analyses suggest that residues 5 and 7 may be dispensable for the transformation of primary baby rat kidney cells by E7, intact residues 19 and 20 are required. Furthermore, negative charges at these residues (TT19-20DD) enhance the pRb-E7 interaction and cells display increased proliferation and invasion capacities. Using a proteomic approach with a phosphorylated peptide spanning the TT19-20 region of HPV16 E7, we have identified a panel of new, phospho-specific E7 interacting partners. These results shed new light on the complexity of N-terminal phosphorylation of E7 and how this can contribute towards expanding the repertoire of E7 targeted pathways

Dual Role of YY1 in HPV Life Cycle and Cervical Cancer Development

Human papillomaviruses (HPVs) are considered to be key etiological agents responsible for the induction and development of cervical cancer. However, it has been suggested that HPV infection alone may not be sufficient to promote cervical carcinogenesis, and other unknown factors might be required to establish the disease. One of the suggested proteins whose deregulation has been linked with oncogenesis is transcription factor Yin Yang 1 (YY1). YY1 is a multifunctional protein that is involved not only in the regulation of gene transcription and protein modification, but can also control important cell signaling pathways, such as cell growth, development, differentiation, and apoptosis. Vital functions of YY1 also indicate that the protein could be involved in tumorigenesis. The overexpression of this protein has been observed in different tumors, and its level has been correlated with poor prognoses of many types of cancers. YY1 can also regulate the transcription of viral genes. It has been documented that YY1 can bind to the HPV long control region and regulate the expression of viral oncogenes E6 and E7; however, its role in the HPV life cycle and cervical cancer development is different. In this review, we explore the role of YY1 in regulating the expression of cellular and viral genes and subsequently investigate how these changes inadvertently contribute toward the development of cervical malignancy

The Activity of <i>Chelidonium majus</i> L. Latex and Its Components on HPV Reveal Insights into the Antiviral Molecular Mechanism

Yellow-orange latex of Chelidonium majus L. has been used in folk medicine as a therapeutic agent against warts and other visible symptoms of human papillomavirus (HPV) infections for centuries. The observed antiviral and antitumor properties of C. majus latex are often attributed to alkaloids contained therein, but recent studies indicate that latex proteins may also play an important role in its pharmacological activities. Therefore, the aim of the study was to investigate the effect of the crude C. majus latex and its protein and alkaloid-rich fractions on different stages of the HPV replication cycle. The results showed that the latex components, such as alkaloids and proteins, decrease HPV infectivity and inhibit the expression of viral oncogenes (E6, E7) on mRNA and protein levels. However, the crude latex and its fractions do not affect the stability of structural proteins in HPV pseudovirions and they do not inhibit the virus from attaching to the cell surface. In addition, the protein fraction causes increased TNFα secretion, which may indicate the induction of an inflammatory response. These findings indicate that the antiviral properties of C. majus latex arise both from alkaloids and proteins contained therein, acting on different stages of the viral replication cycle