Noncanonical HPV carcinogenesis drives radiosensitization of head and neck tumors.

We analyzed transcriptional data from 104 HPV+ (Human papillomavirus) HNSCC (head and neck squamous cell carcinoma) tumors together with two publicly available sources to identify highly robust transcriptional programs (modules) which could be detected consistently despite heterogeneous sequencing and quantification methodologies. Among 22 modules identified, we found a single module that naturally subclassifies HPV+ HNSCC tumors based on a bimodal pattern of gene expression, clusters all atypical features of HPV+ HNSCC biology into a single subclass, and predicts patient outcome in four independent cohorts. The subclass-defining gene set was strongly correlated with Nuclear factor kappa B (NF-κB) target expression. Tumors with high expression of this NF-κB module were rarely associated with activating PIK3CA alterations or viral integration, and also expressed higher levels of HPHPV E2 and had decreased APOBEC mutagenesis. Alternatively, they harbored inactivating alterations of key regulators of NF-κB, TNF receptor associated factor 3 (TRAF3), and cylindromatosis (CYLD), as well as retinoblastoma protein (RB1). HPV+ HNSCC cells in culture with experimental depletion of TRAF3 or CYLD displayed increased expression of the subclass-defining genes, as well as robust radio-sensitization, thus recapitulating both the tumor transcriptional state and improved treatment response observed in patient data. Across all gene sets investigated, methylation to expression correlations were the strongest for the subclass-defining, NF-κB-related genes. Increased tumor-infiltrating CD4+ T cells and increased Estrogen receptors alpha (ERα) expression were identified in NF-κB active tumors. Based on the relatively high rates of cure in HPV+ HNSCC, deintensification of therapy to reduce treatment-related morbidity is being studied at many institutions. Tumor subclassification based on oncogenic subtypes may help guide the selection of therapeutic intensity or modality for patients with HPV+ HNSCC.

Sinonasal complications of severe acute respiratory syndrome coronavirus-2: A single center case series.

Background: The emergence of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has resulted in an unprecedented global pandemic. Most infected patients are either asymptomatic or have mild upper respiratory infection symptoms. However, life-threatening sequelae have been observed. In this report, we reviewed nine cases of patients with severe complications from sinonasal disease in the setting of acute SARS-CoV-2 infection. Methods: IRB approval was obtained prior to study initiation. A retrospective chart review was performed of patients admitted to a tertiary hospital with complex sinonasal symptoms that required otolaryngologic evaluation and management in the setting of concomitant SARS-CoV-2 infection. Results: Nine patients, ranging from ages 3 to 71 years, with sinonasal disease and simultaneous SARS-CoV-2 infection were identified. Initial presentations ranged from asymptomatic infection to mild/moderate disease (nasal obstruction, cough) or more severe sequelae including epistaxis, proptosis, or neurologic changes. SARS-CoV-2 tests were positive from one to 12 days after symptom onset, with three patients receiving SARS-CoV-2-directed treatment. Complex disease presentations included bilateral orbital abscesses, suppurative intracranial infection, cavernous sinus thrombosis with epidural abscess, systemic hematogenous spread with abscess development in four distinct anatomic locations, and hemorrhagic benign adenoidal tissue. Eight of nine patients (88.8%) required operative intervention. Patients with abscesses also required prolonged, culture-directed antibiotic courses. Conclusion: Though most SARS-CoV-2 infections are asymptomatic and/or self-limited, there is significant morbidity and mortality in patients with severe disease sequela as outlined in our reported cases. This suggests early identification and treatment of sinonasal disease in this patient population is critical to minimizing poor outcomes. Further research on the pathophysiology of these atypical presentations is needed. Level of Evidence: 4 (Case Series).

Body Dysmorphic Disorder in Adult Patients With an Orofacial Cleft: An Unseen Psychological Burden.

OBJECTIVES: Facial dysmorphic disorder (FDD), a variant of body dysmorphic disorder, occurs when individuals are preoccupied with perceived defects in their facial appearance. Cleft lip and/or palate (CL/P) requires many clinical interventions and has significant psychological impacts on a patient's perception of appearance. This study identified psychological burdens related to living as an adult with CL/P and characterizes the degree of FDD symptoms in an adult craniofacial population. METHODS: This was a prospective, single-center, cross-sectional case-control study using semi-structured interviews and symptom assessments at a university-based craniofacial center. Patients without CL/P undergoing non-cosmetic facial surgery were recruited as controls (n = 20). Patients with an orofacial cleft (n = 30) were recruited from medical and dental providers at the University of North Carolina. Body Dysmorphic Disorder-Yale Brown Obsessive Compulsive Scale (BBD-YBOCS) scores were collected from a control population and patients with CL/P to assess FDD severity. RESULTS: Demographic factors such age, biological sex, and ethnicity had no significant impact on FDD symptom scores. Patient with CL/P were more likely to have significant FDD symptoms (BDD-YBOCS greater than 16) than patients without CL/P (OR 10.5, CI95 2.7-41.1), and had a mean difference in FDD symptoms scores of 10.04 (p < 0.0001; CI95 5.5-14.6). Patients with CL/P seen by a mental health provider in the past 3 months had 3-fold lower overall FDD symptom scores (OR 0.081; CI95 0.0085-0.77). CONCLUSIONS: Adults with CL/P would benefit from treatment for cleft-specific needs and psychological support as they face unique stressors related to their appearance, including an increase in FDD-associated symptoms. This study emphasizes the importance of recognizing psychological symptoms and providing ongoing multidisciplinary care to adults with CL/P. LEVEL OF EVIDENCE: 3; Individual case-control study Laryngoscope, 133:818-821, 2023.

Development of a Novel Molecular Test for Determining HPV Integration Status in HPV-Positive Oropharynx Cancers.

This diagnostic study describes the development of an assay for human papillomavirus­driven cancers of the oropharynx and the role viral integration could play in the process.

Comprehensive Viral Genotyping Reveals Prognostic Viral Phylogenetic Groups in HPV16-Associated Squamous Cell Carcinoma of the Oropharynx.

Human papillomavirus-positive (HPV+) squamous cell carcinoma of the oropharynx (OPSCC) is the most prevalent HPV-associated malignancy in the United States and is primarily caused by HPV subtype 16 (HPV16). Favorable treatment outcomes have led to increasing interest in treatment deescalation to reduce treatment-related morbidity. Prognostic biomarkers are needed to identify appropriately low-risk patients for reduced treatment intensity. Targeted DNA sequencing including all HPV16 open reading frames was performed on tumors from 104 patients with HPV16+ OPSCC treated at a single center. Genotypes closely related to the HPV16-A1 reference were associated with increased numbers of somatic copy-number variants in the human genome and poor recurrence-free survival (RFS). Genotypes divergent from HPV16-A1 were associated with favorable RFS. These findings were independent of tobacco smoke exposure. Total RNA sequencing was performed on a second independent cohort of 89 HPV16+ OPSCC cases. HPV16 genotypes divergent from HPV16-A1 were again validated in this independent cohort, to be prognostic of improved RFS in patients with moderate (less than 30 pack-years) or low (no more than 10 pack-years) of tobacco smoke exposure. In summary, we show in two independent cohorts that viral sequence divergence from the HPV16-A1 reference is correlated with improved RFS in patients with moderate or low tobacco smoke exposure. IMPLICATIONS: HPV16 genotype is a potential biomarker that could be easily adopted to guide therapeutic decision-making related to deescalation therapy.

Early expression of IL-10, IL-12, ARG1, and NOS2 genes in peripheral blood mononuclear cells synergistically correlate with patient outcome after burn injury.

BACKGROUND: No methods exist to rapidly and accurately quantify the immune insult created by burn injuries. The development of a rapid, noninvasive clinical biomarker assay that evaluates a burn patient's underlying immune dysfunction and predicts clinical outcomes could transform burn care. We aimed to determine a set of peripheral biomarkers that correlates with clinical outcomes of burn patients. METHODS: This prospective observational study enrolled two patient cohorts within a single burn center into an institutionally approved institutional review board study. Blood draws were performed <48 hours after injury. Initial unbiased immune gene expression analysis compared 23 burn patients and 6 healthy controls using multiplex immune gene expression analysis of RNA from peripheral blood mononuclear cells. We then performed confirmatory outcomes analysis in 109 burn patients and 19 healthy controls using a targeted rapid quantitative polymerase chain reaction. Findings were validated and modeled associations with clinical outcomes using a regression model. RESULTS: A total of 149 genes with a significant difference in expression from burn patients compared with controls were identified. Pathway analysis identified pathways related to interleukin (IL)-10 and inducible nitric oxide synthase signaling to have significant z scores. quantitative polymerase chain reaction analysis of IL-10, IL-12, arginase 1 (ARG1), and inducible nitric oxide synthase demonstrated that burn injury was associated with increased expression of ARG1 and IL-10, and decreased expression of nitric oxide synthase 2 (NOS2) and IL-12. Burn severity, acute lung injury, development of infection, failure of skin autograft, and mortality significantly correlated with expression of one or more of these genes. Ratios of IL-10/IL-12, ARG1/NOS2, and (ARG1-IL-10)/(NOS2-IL-12) transcript levels further improved the correlation with outcomes. Using a multivariate regression model, adjusting for patient confounders demonstrated that (ARG1-IL-10)/(NOS2-IL-12) significantly correlated with burn severity and development of acute lung injury. CONCLUSION: We present a means to predict patient outcomes early after burn injury using peripheral blood, allowing early identification of underlying immune dysfunction. LEVEL OF EVIDENCE: Prognostic/Epidemiological; Level II.

Anatomic Optical Coherence Tomography (aOCT) for Evaluation of the Internal Nasal Valve.

OBJECTIVES/HYPOTHESIS: To establish the utility of anatomic optical coherence tomography (aOCT) in evaluating internal nasal valve (INV). STUDY DESIGN: Anatomic specimen imaging study. METHODS: Fresh-harvested human specimen heads were evaluated using both computed tomography (CT) imaging as well as using aOCT. Scans were performed at three time points: 1) After septoplasty for cartilage harvest, 2) after placement of butterfly graft (BFG), and 3) after placement of bilateral spreader grafts (SG). Imaging data were then converted into 3D models of the nasal airway. CT- and aOCT-generated models were compared by both static volumetric analysis and computational fluid dynamics (CFD) to predict nasal resistance and pressure. RESULTS: Scans using aOCT showed comparable results to CT in terms of volumetric parameters both before and after intervention. Analysis of aOCT data by CFD demonstrated decrease in pressure after SG or BFG intervention. No statistically significant difference was observed when comparing CT- and aOCT-generated calculations of pressure or resistance. CONCLUSION: The INV can be imaged in a static fashion using aOCT technology. Advantages over traditional CT imaging include lack of exposure to radiation and rapid scan time. In addition, in-office use is possible as aOCT technology develops. Further investigation will be necessary to define the role of aOCT in the dynamic evaluation of this vital component of the nasal airway. LEVEL OF EVIDENCE: 3 Laryngoscope, 132:2148-2156, 2022.

HPV in the malignant transformation of sinonasal inverted papillomas: A meta-analysis.

OBJECTIVES: To date, there is still a significant debate on the role of human papilloma virus (HPV) infection in transformation of inverted papillomas (IPs) to squamous cell carcinoma (SCC). This study was designed to determine if the presence of HPV in a sinonasal IP increases the risk of malignant transformation to IPSCC. METHODS: Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, 19 high-quality case-control and cohort studies with tissue-diagnosed IP or IPSCC and HPV diagnosis were analyzed. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using the Mantel-Haenszel method with correction for random effects. Subgroup, publication bias and a sensitivity analyses were also performed. RESULTS: Nineteen studies with minimal bias met the inclusion criteria for quality and identified HPV infection in an IP. The pooled data revealed a strong association with progression to malignancy with an unweighted, pooled OR of 2.38 (CI95 1.47 to 3.83) and a weighted OR of 2.80 (CI95 1.42 to 5.51). Sensitivity analysis revealed that no single study contributed significantly to our pooled OR calculations (ORs 2.52 to 3.57). Subgroup analyses stratified by publication date, nucleic acid target, HPV detection method and type, sample size, and region all demonstrated a positive association of HPV with IPSCC. CONCLUSIONS: There appears to be a significant association between HPV infection and malignant transformation of IPs. While HPV testing is not currently the standard of care for IPs, these data suggest a link between the two and suggest further studies should be performed to identify a link between the virus and malignant transformation.

High-Throughput NanoString Analysis of Oncogenic Human Papillomavirus and Tumor Microenvironment Transcription in Head and Neck Squamous Cell Carcinoma.

Human papillomaviruses (HPVs), specifically high-risk HPVs, are responsible for up to 3% of all cancers in women and up to 2% of all cancers in men. They have been identified as the etiological agent of cervical cancer and have been increasingly found to be the driver behind head and neck cancers of the oropharynx. A system in which we can simultaneously observe transcriptional changes to both a host's tumor microenvironment and its associated oncogenic driver (e.g., HPV) would be highly valuable for understanding HPV's role in tumorigenesis. This article describes a detailed methodology for utilizing high-throughput RNA analysis to study viral transcription in formalin-fixed, paraffin-embedded clinical tumor samples. Although our lab utilizes these methods for the study of head and neck cancer, the principles contained within are widely applicable to all fields of HPV study. © 2021 Wiley Periodicals LLC. Basic Protocol: HPV16 transcript analysis using NanoString Support Protocol 1: Preparation of RNA from formalin-fixed, paraffin-embedded slides Support Protocol 2: Preparation of RNA from cell lysates Support Protocol 3: Fluorometric RNA concentration and RNA integrity analysis Support Protocol 4: Determination of input RNA based on DV300 calculation.

A Comparison of Sphenoid Sinus Osteoneogenesis in Aspirin-Exacerbated Respiratory Disease.

BACKGROUND: Aspirin-exacerbated respiratory disease (AERD) is characterized by excessive leukotriene production, diffuse polyp burden and osteitic bone changes. These bony changes have not been previously characterized. OBJECTIVE: The aim of this radiographic study is to characterize the bony changes noted on computed tomography (CT) scans of the sphenoid sinus in patients with AERD compared to other diseased sinonasal inflammatory states and non-diseased controls. METHODS: A retrospective review of 43 patients with clinically confirmed AERD were included and compared to 22 non-diseased, 9 allergic fungal sinusitis, and 43 chronic rhinosinusitis controls (23 without polyps and 18 with polyps). Comparative measurements were performed using fine-cut CT scans. Sites of comparison were the intersinus septum, the left and right lateral sphenoid wall, the roof, and left and right floor of the sphenoid sinus. Standardized measurements were averaged by two separate rhinologists. RESULTS: Patients with AERD had an average statistically significant increase in bone thickness compared to healthy and diseased controls in nearly every site with the most pronounced changes in the intersinus septum (p < 0.05). CONCLUSION: Patients with AERD have significantly increased thickness of the sphenoid bone compared to control groups with the most pronounced difference in the intersinus septum. These findings may help clinicians increase suspicion for a diagnosis of AERD who clinically have diffuse nasal polyposis.

Nasopharyngeal Hyalinizing Clear Cell Carcinoma: A Case Report and Review of the Literature.

BACKGROUND: Hyalinizing clear cell carcinomas (HCCCs) are rare, low-grade, malignant tumors which most often arise from the minor salivary glands primarily in palate and tongue but can arise in any location with minor salivary glands including the nasopharynx. METHODS: A case report of primary nasopharyngeal HCCC is presented. Because of the rarity of this tumor and location, a literature search was conducted to determine the most common presenting symptoms, treatment strategies, and outcomes. RESULTS: A 48-year-old man underwent biopsy of a 4.5 cm mass of the right nasopharynx with pathology suggesting an intermediate grade mucoepidermoid carcinoma. After discussing management with the patient, an endoscopic resection was performed. Final pathology revealed an HCCC which was confirmed after negative Mastermind-like 2 (MAML2) and positive Ewing sarcoma breakpoint region 1 (ESWR1) gene rearrangements on fluorescence in situ hybridization (FISH) studies. Literature review of other nasopharyngeal HCCC cases shows diverse presentation and overall excellent prognosis through surgical and radiation therapy. CONCLUSION: HCCCs are rare, low-grade malignant tumors of the minor salivary glands and can present as a nasopharyngeal mass. Presenting symptoms are diverse but frequently involve otologic and sinonasal disturbances. HCCC is an indolent tumor with an excellent prognostic outcome when treated appropriately with surgical resection and adjuvant radiotherapy.

Clinical characteristics of CNS metastases from primary gynecologic cancers.

The development of brain and central nervous system (CNS) metastases from primary gynecologic cancers is an extremely uncommon but deadly process. Through this retrospective case series of patients treated at a single institution from 2004 to 2018, we aim to explore potential clinical patterns of this phenomenon with respect to primary tumor type, histology, and symptomatology. A total of 42 patients were identified with CNS metastases, with 24 patients having endometrial cancer, 9 patients with ovarian cancer, 5 patients with cervical cancer, and 4 patients with gestational trophoblastic neoplasia (GTN). The two most common presenting complaints were headache and ataxia. Most patients (67%) presented with more than one lesion on imaging and the frontal lobe was most likely to be involved. The median age of diagnosis for both primary cancer and CNS metastasis were significantly younger in the GTN group when compared to other cancers. Meningeal involvement was more prevalent in patients with cervical cancer. Over 83% of endometrial cancer patients in this cohort had type II histologies, a significantly higher percentage than that in the general population. While the rarity of CNS metastases in primary gynecologic malignancies precludes routine screening, patients diagnosed with more aggressive histologic subtypes of endometrial and uterine cancers may benefit from a lowered threshold of brain imaging in the context of new onset neurological symptoms.

RNA Oncoimmune Phenotyping of HPV-Positive p16-Positive Oropharyngeal Squamous Cell Carcinomas by Nodal Status.

Importance: Clinical trials that deintensify treatment for patients with suspected human papillomavirus (HPV)-positive oropharyngeal squamous cell carcinoma (OPSCC) use p16 expression to identify HPV-mediated tumors and guide treatment. While p16 staining has a strong correlation with good outcomes, approximately 12% of p16-positive patients have recurrent disease. Biomarkers that reveal tumor-specific characteristics, such as nodal involvement, may change therapy decisions. Objective: To assess whether if a tumor-specific genetic signature exists for node-negative vs node-positive HPV 16-positive/p16-positive OPSCCs. Design, Setting, and Participants: This was a retrospective cohort study with randomized case selection for p16 OPSCCs undertaken at a university-based, tertiary care cancer center. Samples were collected from patients with p16-positive OPSCC. A total of 21 HPV 16/p16-positive tumors were used in this study. Main Outcomes and Measures: Gene expression profiles of node-negative vs node-positive tumor samples were evaluated using a differential expression analysis approach and the sensitivity and specificity of a molecular signature was determined. Results: Among the 21 patients in the study (3 women, 18 men; mean [SD] age, 54.6 [9.6] years), 6 had node-negative disease and 15 had node-positive disease. Using differential expression analysis, we found 146 genes that were significantly different in patients with node-negative disease vs those with node-positive disease, of which 15 genes were used to create a genetic signature that could distinguish node-negative-like from node-positive-like disease. The resultant molecular signature has a sensitivity of 88.2% (95% CI, 63.6%-98.5%) and specificity of 85.7% (95% CI, 42.1%-99.6%). The positive likelihood ratio of this signature was 6.1 (95% CI, 1.0-38.2) and the negative likelihood ratio was 0.1 (95% CI, 0.04-0.5). Given this population's prevalence of node-positive disease of 70.8%, the positive- and negative-predicative values for this gene signature were 93.7% (95% CI, 70.8%-98.9%) and 75.0% (95% CI, 44.1%-92.0%), respectively. In addition, we developed a gene signature using agnostic, machine learning software that identified a 40-gene profile that predicts node-negative disease from node-positive disease (area under the curve, 0.93; 95% CI, 0.63-1.00). Conclusions and Relevance: Many HPV-16 and p16-positive tumors are treated as "lower-risk," but they do not have similar genetic compositions at the biological level. The identification of subgroups with unique expression patterns, such as those with nodal metastases, may guide physicians toward alternative or more aggressive therapies. In our study, unguided clustering suggested that that the larger biological characteristics of a tumor could be a better prognostic biomarker.

Blocking CXCL1-dependent neutrophil recruitment prevents immune damage and reduces pulmonary bacterial infection after inhalation injury.

Smoke inhalation associated with structural fires, wildfires, or explosions leads to lung injury, for which innovative and clinically relevant animal models are needed to develop effective therapeutics. We have previously reported that damage-associated molecular patterns (DAMPs) and anti-inflammatory cytokines correlate with infectious complications in patients diagnosed with inhalational injury. In this study, we describe a novel and translational murine model of acute inhalational injury characterized by an accumulation of protein and neutrophils in the bronchoalveolar space, as well as histological evidence of tissue damage. Mice were anesthetized, and a cannula was placed in the trachea and exposed to smoldering plywood smoke three times for 2-min intervals in a smoke chamber. Here we demonstrate that this model recapitulates clinically relevant phenotypes, including early release of double-stranded DNA (dsDNA), IL-10, monocyte chemoattractant protein (MCP)-1, and CXCL1 along with neutrophilia early after injury, accompanied by subsequent susceptibility to opportunistic infection with Pseudomonas aeruginosa. Further investigation of the model, and in turn a reanalysis of patient samples, revealed a late release of the DAMP hyaluronic acid (HA) from the lung. Using nitric oxide synthase-deficient mice, we found that Nos2 was required for increases in IL-10, MCP-1, and HA following injury but not release of dsDNA, CXCL1 expression, early neutrophilia, or susceptibility to opportunistic infection. Depletion of CXCL1 attenuated early neutrophil recruitment, leading to decreased histopathology scores and improved bacterial clearance in this model of smoke inhalation. Together, these data highlight the potential therapeutic benefit of attenuating neutrophil recruitment in the first 24 h after injury in patients.

Sp100 colocalizes with HPV replication foci and restricts the productive stage of the infectious cycle.

We have shown previously that Sp100 (a component of the ND10 nuclear body) represses transcription, replication and establishment of incoming human papillomavirus (HPV) DNA in the early stages of infection. In this follow up study, we show that Sp100 does not substantially regulate viral infection in the maintenance phase, however at late stages of infection Sp100 interacts with amplifying viral genomes to repress viral processes. We find that Sp100 localizes to HPV16 replication foci generated in primary keratinocytes, to HPV31 replication foci that form in differentiated cells, and to HPV16 replication foci in CIN 1 cervical biopsies. To analyze this further, Sp100 was down regulated by siRNA treatment of differentiating HPV31 containing cells and levels of viral transcription and replication were assessed. This revealed that Sp100 represses viral transcription and replication in differentiated cells. Analysis of Sp100 binding to viral chromatin showed that Sp100 bound across the viral genome, and that binding increased at late stages of infection. Therefore, Sp100 represses the HPV life cycle at both early and late stages of infection.

Host cell restriction factors that limit transcription and replication of human papillomavirus.

The life cycle of human papillomaviruses (HPV) is tightly regulated by the differentiation state of mucosal and cutaneous keratinocytes. To counteract viral infection, constitutively expressed cellular factors, which are defined herein as restriction factors, directly mitigate viral gene expression and replication. In turn, some HPV gene products target these restriction factors and abrogate their anti-viral effects to establish efficient gene expression and replication programs. Ironically, in certain circumstances, this delicate counterbalance between viral gene products and restriction factors facilitates persistent infection by HPVs. This review serves to recapitulate the current knowledge of nuclear restriction factors that directly affect the HPV infectious cycle.

Novel recombinant papillomavirus genomes expressing selectable genes.

Papillomaviruses infect and replicate in keratinocytes, but viral proteins are initially expressed at low levels and there is no effective and quantitative method to determine the efficiency of infection on a cell-to-cell basis. Here we describe human papillomavirus (HPV) genomes that express marker proteins (antibiotic resistance genes and Green Fluorescent Protein), and can be used to elucidate early stages in HPV infection of primary keratinocytes. To generate these recombinant genomes, the late region of the oncogenic HPV18 genome was replaced by CpG free marker genes. Insertion of these exogenous genes did not affect early replication, and had only minimal effects on early viral transcription. When introduced into primary keratinocytes, the recombinant marker genomes gave rise to drug-resistant keratinocyte colonies and cell lines, which maintained the extrachromosomal recombinant genome long-term. Furthermore, the HPV18 "marker" genomes could be packaged into viral particles (quasivirions) and used to infect primary human keratinocytes in culture. This resulted in the outgrowth of drug-resistant keratinocyte colonies containing replicating HPV18 genomes. In summary, we describe HPV18 marker genomes that can be used to quantitatively investigate many aspects of the viral life cycle.

Sp100 provides intrinsic immunity against human papillomavirus infection.

UNLABELLED: Most DNA viruses associate with, and reorganize, nuclear domain 10 (ND10) bodies upon entry into the host nucleus. In this study, we examine the roles of the ND10 components PML, Sp100, and Daxx in the establishment of human papillomavirus type 18 (HPV18) infection of primary human keratinocytes. HPV18 DNA or HPV18 quasivirus was introduced into primary human keratinocytes depleted of each ND10 protein by small interfering RNA technology, and genome establishment was determined by using a quantitative immortalization assay and measurements of viral transcription and DNA replication. Keratinocyte depletion of Sp100 resulted in a substantial increase in the number of HPV18-immortalized colonies and a corresponding increase in viral transcription and DNA replication. However, Sp100 repressed viral transcription and replication only during the initial stages of viral establishment, suggesting that Sp100 acts as a repressor of incoming HPV DNA. IMPORTANCE: The intrinsic immune system provides a first-line defense against invading pathogens. Host cells contain nuclear bodies (ND10) that are important for antiviral defense, yet many DNA viruses localize here upon cell entry. However, viruses also disrupt, reorganize, and modify individual components of the bodies. In this study, we show that one of the ND10 components, Sp100, limits the infection of human skin cells by human papillomavirus (HPV). HPVs are important pathogens that cause many types of infection of the cutaneous and mucosal epithelium and are the causative agents of several human cancers. Understanding how host cells counteract HPV infection could provide insight into antimicrobial therapies that could limit initial infection.

Hitchhiking on host chromatin: how papillomaviruses persist.

Persistent viruses need mechanisms to protect their genomes from cellular defenses and to ensure that they are efficiently propagated to daughter host cells. One mechanism by which papillomaviruses achieve this is through the association of viral genomes with host chromatin, mediated by the viral E2 tethering protein. Association of viral DNA with regions of active host chromatin ensures that the virus remains transcriptionally active and is not relegated to repressed heterochromatin. In addition, viral genomes are tethered to specific regions of host mitotic chromosomes to efficiently partition their DNA to daughter cells. Vegetative viral DNA replication also initiates at specific regions of host chromatin, where the viral E1 and E2 proteins initiate a DNA damage response that recruits cellular DNA damage and repair proteins to viral replication foci for efficient viral DNA synthesis. Thus, these small viruses have capitalized on interactions with chromatin to efficiently target their genomes to beneficial regions of the host nucleus. This article is part of a Special Issue entitled: Chromatin in time and space.