A gain-of-function HCN4 mutant in the HCN domain is responsible for inappropriate sinus tachycardia in a Spanish family.

In a family with inappropriate sinus tachycardia (IST), we identified a mutation (p.V240M) of the hyperpolarization-activated cyclic nucleotide-gated type 4 (HCN4) channel, which contributes to the pacemaker current (If) in human sinoatrial node cells. Here, we clinically study fifteen family members and functionally analyze the p.V240M variant. Macroscopic (IHCN4) and single-channel currents were recorded using patch-clamp in cells expressing human native (WT) and/or p.V240M HCN4 channels. All p.V240M mutation carriers exhibited IST that was accompanied by cardiomyopathy in adults. IHCN4 generated by p.V240M channels either alone or in combination with WT was significantly greater than that generated by WT channels alone. The variant, which lies in the N-terminal HCN domain, increased the single-channel conductance and opening frequency and probability of HCN4 channels. Conversely, it did not modify the channel sensitivity for cAMP and ivabradine or the level of expression at the membrane. Treatment with ivabradine based on functional data reversed the IST and the cardiomyopathy of the carriers. In computer simulations, the p.V240M gain-of-function variant increases If and beating rate and thus explains the IST of the carriers. The results demonstrate the importance of the unique HCN domain in HCN4, which stabilizes the channels in the closed state.

Understanding different dominance patterns in western Amazonian forests.

Dominance of neotropical tree communities by a few species is widely documented, but dominant trees show a variety of distributional patterns still poorly understood. Here, we used 503 forest inventory plots (93,719 individuals ≥2.5 cm diameter, 2609 species) to explore the relationships between local abundance, regional frequency and spatial aggregation of dominant species in four main habitat types in western Amazonia. Although the abundance-occupancy relationship is positive for the full dataset, we found that among dominant Amazonian tree species, there is a strong negative relationship between local abundance and regional frequency and/or spatial aggregation across habitat types. Our findings suggest an ecological trade-off whereby dominant species can be locally abundant (local dominants) or regionally widespread (widespread dominants), but rarely both (oligarchs). Given the importance of dominant species as drivers of diversity and ecosystem functioning, unravelling different dominance patterns is a research priority to direct conservation efforts in Amazonian forests.

Probabilistic coverage of the frontal aslant tract in young adults: Insights into individual variability, lateralization, and language functions.

The frontal aslant tract (FAT) is a crucial neural pathway of language and speech, but little is known about its connectivity and segmentation differences across populations. In this study, we investigate the probabilistic coverage of the FAT in a large sample of 1065 young adults. Our primary goal was to reveal individual variability and lateralization of FAT and its structure-function correlations in language processing. The study utilized diffusion MRI data from 1065 subjects obtained from the Human Connectome Project. Automated tractography using DSI Studio software was employed to map white matter bundles, and the results were examined to study the population variation of the FAT. Additionally, anatomical dissections were performed to validate the fiber tracking results. The tract-to-region connectome, based on Human Connectome Project-MMP parcellations, was utilized to provide population probability of the tract-to-region connections. Our results showed that the left anterior FAT exhibited the most substantial individual differences, particularly in the superior and middle frontal gyrus, with greater variability in the superior than the inferior region. Furthermore, we found left lateralization in FAT, with a greater difference in coverage in the inferior and posterior portions. Additionally, our analysis revealed a significant positive correlation between the left FAT inferior coverage area and the performance on the oral reading recognition (p = .016) and picture vocabulary (p = .0026) tests. In comparison, fractional anisotropy of the right FAT exhibited marginal significance in its correlation (p = .056) with Picture Vocabulary Test. Our findings, combined with the connectivity patterns of the FAT, allowed us to segment its structure into anterior and posterior segments. We found significant variability in FAT coverage among individuals, with left lateralization observed in both macroscopic shape measures and microscopic diffusion metrics. Our findings also suggested a potential link between the size of the left FAT's inferior coverage area and language function tests. These results enhance our understanding of the FAT's role in brain connectivity and its potential implications for language and executive functions.

Comprehensive Genomic Analysis of Cemento-Ossifying Fibroma.

Cemento-ossifying fibroma (COF) of the jaws is currently classified as a benign mesenchymal odontogenic tumor, and only targeted approaches have been used to assess its genetic alterations. A minimal proportion of COFs harbor CDC73 somatic mutations, and copy number alterations (CNAs) involving chromosomes 7 and 12 have recently been reported in a small proportion of cases. However, the genetic background of COFs remains obscure. We used a combination of whole-exome sequencing and RNA sequencing to assess somatic mutations, fusion transcripts, and CNAs in a cohort of 12 freshly collected COFs. No recurrent fusions have been identified among the 5 cases successfully analyzed by RNA sequencing, with in-frame fusions being detected in 2 cases (MARS1::GOLT1B and PARG::BMS1 in one case and NCLN::FZR1 and NFIC::SAMD1 in the other case) and no candidate fusions identified for the remaining 3 cases. No recurrent pathogenic mutations were detected in the 11 cases that had undergone whole-exome sequencing. A KRAS p.L19F missense variant was detected in one case, and 2 CDC73 deletions were detected in another case. The other variants were of uncertain significance and included variants in PC, ACTB, DOK6, HACE1, and COL1A2 and previously unreported variants in PTPN14, ATP5F1C, APOBEC1, HDAC5, ATF7IP, PARP2, and ACTR3B. The affected genes do not clearly converge on any signaling pathway. CNAs were detected in 5/11 cases (45%), with copy gains involving chromosome 12 occurring in 3/11 cases (27%). In conclusion, no recurrent fusions or pathogenic variants have been detected in the present COF cohort, with copy gains involving chromosome 12 occurring in 27% of cases.

Targeted therapies in ameloblastomas and amelobastic carcinoma-A systematic review.

Targeted therapy has the potential to be used in the neoadjuvant setting for odontogenic tumors, reducing the morbidities associated with major surgery. In this regard, the aim of this study was to summarize the current evidence on the different forms of targeted therapy, effectiveness, and drawbacks of this course of treatment. Four databases were searched electronically without regard to publication date or language. Grey literature searches and manual searches were also undertaken. Publications with sufficient clinical data on targeted therapy for odontogenic tumors were required to meet the criteria for eligibility. The analysis of the data was descriptive. A total of 15 papers comprising 17 cases (15 ameloblastomas and 2 ameloblastic carcinomas) were included. Numerous mutations were found, with BRAF V600E being most common. Dabrafenib was the most utilized drug in targeted therapy. Except for one case, the treatment reduced the size of the lesion (16/17 cases), showing promise. Most of the adverse events recorded were mild, such as skin issues, voice changes, abnormal hair texture, dry eyes, and systemic symptoms (e.g., fatigue, joint pain, and nausea). It is possible to reach the conclusion that targeted therapy for ameloblastoma and ameloblastic carcinoma may be a useful treatment strategy, based on the findings of the included studies.

NMDA receptor-BK channel coupling regulates synaptic plasticity in the barrel cortex.

Postsynaptic N-methyl-D-aspartate receptors (NMDARs) are crucial mediators of synaptic plasticity due to their ability to act as coincidence detectors of presynaptic and postsynaptic neuronal activity. However, NMDARs exist within the molecular context of a variety of postsynaptic signaling proteins, which can fine-tune their function. Here, we describe a form of NMDAR suppression by large-conductance Ca2+- and voltage-gated K+ (BK) channels in the basal dendrites of a subset of barrel cortex layer 5 pyramidal neurons. We show that NMDAR activation increases intracellular Ca2+ in the vicinity of BK channels, thus activating K+ efflux and strong negative feedback inhibition. We further show that neurons exhibiting such NMDAR-BK coupling serve as high-pass filters for incoming synaptic inputs, precluding the induction of spike timing-dependent plasticity. Together, these data suggest that NMDAR-localized BK channels regulate synaptic integration and provide input-specific synaptic diversity to a thalamocortical circuit.

Clinical, immunological, and microbiological analysis of the association between periodontitis and COVID-19: a case-control study.

PURPOSE: Periodontitis and coronavirus disease (COVID-19) share risk factors and activate similar immunopathological pathways, intensifying systemic inflammation. This study investigated the clinical, immunological and microbiological parameters in individuals with COVID-19 and controls, exploring whether periodontitis-driven inflammation contributes to worsening COVID-19 endpoints. METHODS: Case (positive RT-PCR for SARS-CoV-2) and control (negative RT-PCR) individuals underwent clinical and periodontal assessments. Salivary levels of TNF-α, IL-6, IL-1ß, IL-10, OPG, RANKL, neutrophil extracellular traps, and subgingival biofilm were analyzed at two timepoints. Data on COVID-19-related outcomes and comorbidity information were evaluated from medical records. RESULTS: Ninety-nine cases of COVID-19 and 182 controls were included for analysis. Periodontitis was associated with more hospitalization (p = 0.009), more days in the intensive care unit (ICU) (p = 0.042), admission to the semi-ICU (p = 0.047), and greater need for oxygen therapy (p = 0.042). After adjustment for confounders, periodontitis resulted in a 1.13-fold increase in the chance of hospitalization. Salivary IL-6 levels (p = 0.010) were increased in individuals with COVID-19 and periodontitis. Periodontitis was associated with increased RANKL and IL-1ß after COVID-19. No significant changes were observed in the bacterial loads of the periodontopathogens Porphyromona gingivalis, Aggregatibacter actinomycetemcomitans, Tanerella forsythia, and Treponema denticola. CONCLUSIONS: Periodontitis was associated with worse COVID-19 outcomes, suggesting the relevance of periodontal care to reduce the burden of overall inflammation. Understanding the crosstalk between SARS-CoV-2 infection and chronic conditions such as periodontitis that can influence disease outcome is important to potentially prevent complications of COVID-19.

Levels of Small Extracellular Vesicles Containing hERG-1 and Hsp47 as Potential Biomarkers for Cardiovascular Diseases.

The diagnosis of cardiovascular disease (CVD) is still limited. Therefore, this study demonstrates the presence of human ether-a-go-go-related gene 1 (hERG1) and heat shock protein 47 (Hsp47) on the surface of small extracellular vesicles (sEVs) in human peripheral blood and their association with CVD. In this research, 20 individuals with heart failure and 26 participants subjected to cardiac stress tests were enrolled. The associations between hERG1 and/or Hsp47 in sEVs and CVD were established using Western blot, flow cytometry, electron microscopy, ELISA, and nanoparticle tracking analysis. The results show that hERG1 and Hsp47 were present in sEV membranes, extravesicularly exposing the sequences 430AFLLKETEEGPPATE445 for hERG1 and 169ALQSINEWAAQTT- DGKLPEVTKDVERTD196 for Hsp47. In addition, upon exposure to hypoxia, rat primary cardiomyocytes released sEVs into the media, and human cardiomyocytes in culture also released sEVs containing hERG1 (EV-hERG1) and/or Hsp47 (EV-Hsp47). Moreover, the levels of sEVs increased in the blood when cardiac ischemia was induced during the stress test, as well as the concentrations of EV-hERG1 and EV-Hsp47. Additionally, the plasma levels of EV-hERG1 and EV-Hsp47 decreased in patients with decompensated heart failure (DHF). Our data provide the first evidence that hERG1 and Hsp47 are present in the membranes of sEVs derived from the human cardiomyocyte cell line, and also in those isolated from human peripheral blood. Total sEVs, EV-hERG1, and EV-Hsp47 may be explored as biomarkers for heart diseases such as heart failure and cardiac ischemia.

Fusion genes aiding the diagnosis of soft tissue tumours of the oral cavity: From bench to bedside.

Soft tissue tumours (STT) are a heterogeneous group of benign, malignant, and intermediate/borderline mesenchymal tumours. In the oral and maxillofacial region, less than 3% of all lesions correspond to benign STT and <1% are sarcomas. Overlapping microscopic features may lead to quite challenging diagnostic processes. Translocations and fusion genes are frequent, and type-specific genetic alterations are detected in these tumours. The detection of such alterations by classic cytogenetic, FISH, RT-PCR or NGS can help to define the diagnosis. This narrative review aims to review fusion genes reported for STT that affect the oral cavity and their use in diagnostic molecular pathology. Basic concepts regarding mechanisms of fusion genes formation are presented to clarify this information for surgical pathologists. The chromosomal rearrangements and fusion genes of adipocytic, fibroblastic and myofibroblastic, vascular, pericytic, smooth muscle, skeletal muscle, chondro-osseous, and uncertain origin STT are summarised. The advance in molecular pathology techniques has led not only to a better understanding of the molecular pathogenesis of STT, but also to the development of helpful diagnostic tools. Therefore, it is important for the oral and head and neck pathologists to familiarise with the signature rearrangements and fusion genes for each tumour.

Beyond the hype: A critical appraisal of the limitations and misconceptions of systematic reviews in the Oral pathology and medicine field.

BACKGROUND: Systematic reviews (SRs) have become a popular approach for evidence-based practice, being considered a lens through which evidence is viewed and applied. However, several published studies have been identified as scoping reviews rather than SRs. This methodological error can negatively impact clinical decision-making or new research conceptualization. AIM: This letter focuses on the increasing number of SRs in oral pathology and medicine, highlighting the most frequent methodological mistakes. RESULTS: We providing general guidance to help researchers conceptualize better their SRs and for the critical evaluation of SRs by scientific journal reviewers. CONCLUSION: Clinicians, pathologists, and reviewers, must ensure the quality of the published information.

Evolution tumour models paving the way for understanding oral carcinogenesis.

Throughout the centuries, the world's outstanding scientists and research groups have gathered their efforts to characterise the initiation and progression of malignant neoplasms. The temporal dissection of tumourigenesis provided by phylogenetic studies is one of the milestones in understanding cancer; however, some black boxes are still unsolved. Currently, there is no consensus regarding the development of oral squamous cell carcinoma (OSCC), the leading cancer of the head and neck region. Oral epithelial dysplasia (OED) may precede oral cancer and, occasionally, be clinically evident as white, red or mixed mucosal lesions, called oral potentially malignant disorders (OPMD). In a stepwise view of oral carcinogenesis, OED and OPMD have been considered harbingers of oral cancer. Nevertheless, the malignant transformation of OPMD is a rare event. Most of these disorders remain benign and can even regress, making it challenging to formulate evolutionary hypotheses for OSCC initiation. Deciphering OED evolution is vital to highlight the potential drivers of oral carcinogenesis and molecular targets for OSCC preventative and therapeutic strategies. This narrative review synthesises the main concepts of evolutionary theories and discusses which of them better explains OED development and malignant transformation.

A conservative approach for unicystic ameloblastoma: Retrospective clinic-pathologic analysis of 12 cases.

BACKGROUND: Unicystic ameloblastoma is an encapsulated odontogenic neoplasm with a single cyst cavity. The conservative or aggressive surgical approaches used to treat the tumor directly affect recurrence rates. However, there is a lack of a standard protocol that can guide its management. STUDY DESIGN: We retrospectively reviewed the clinicopathological findings and therapeutical procedures of 12 unicystic ameloblastoma cases treated by the same surgeon during the past 20 years. METHODS: All cases of unicystic ameloblastoma diagnosed by biopsy and treated by the same surgeon between 2002 and 2022 were reviewed. Eligibility criteria were patients with completely filled-out charts containing the follow-up period and confirmation of the diagnoses based on the microscopic findings of the whole excised specimens. Data collected were categorized into clinical, radiographic, histological, surgical, and recurrence aspects. RESULTS: There was a female predilection (2:1), and ages ranged between 18 and 61 years (mean: 27.25, ±12.45). Almost all (92%) affected the posterior mandible. Radiographically, the mean length of the lesions was 46.14 mm ± 14.28 mm which 92% were unilocular and 8.3% multilocular. Root resorption (n = 7, 58%), tooth displacement (n = 9, 75%), and cortical perforation (n = 5, 42%) were also observed. The mural histological subtype corresponded to 9 (75%) of the cases. The same conservative protocol was performed in all cases. The follow-up period ranged between 12 and 240 months (~62 ± 65) and recurrence occurred in only one patient (8%). CONCLUSION: Our findings suggest a conservative approach should be the first option for unicystic ameloblastoma treatment, even for those with mural proliferation.

Interrogation of TERT promoter hotspot mutations in ameloblastoma and ameloblastic carcinoma.

BACKGROUND: TERT promoter mutations increase telomerase activity, conferring cell immortality. The coexistence of TERT promoter mutations with BRAFV600E is associated with aggressiveness. Ameloblastoma and ameloblastic carcinoma are infiltrative neoplasms that harbor BRAFV600E; however, it remains unknown if these odontogenic tumors also show TERT promoter mutations. METHODS: Genomic DNA of paraffin-embedded ameloblastomas (n = 6) and ameloblastic carcinomas (n = 3) were Sanger-sequenced to assess the hotspot TERT promoter mutations C228T and C250T. BRAFV600E status was screened by TaqMan allele-specific quantitative polymerase chain reaction. RESULTS: None of the samples harbored TERT promoter mutations. The BRAFV600E mutation was positive in 3 of 6 of ameloblastomas and in 1 of 3 of ameloblastic carcinomas. CONCLUSION: The absence of TERT promoter mutation in the samples indicates that this molecular event is not relevant to the tumors' pathogenesis. Further studies are necessary to explore undefined genetic or epigenetic mechanisms related to TERT-upregulation in ameloblastoma, and the telomerase activity in ameloblastic carcinoma.

Chronic rhinosinusitis with nasal polyps does not harbor KRAS, BRAF, and EGFR mutations.

BACKGROUND: Chronic rhinosinusitis is a chronic inflammation of the nasal mucosa and nasal polyps are present in ~25%-30% of cases (chronic rhinosinusitis with nasal polyps [CRSwNP]). CRSwNP is associated with significant morbidity and decreased quality of life, making it clinically important. Inflammation leads to DNA damage and DNA mutations occur in some inflammatory diseases. Notably, mutations in KRAS, BRAF, and EGFR have been reported in different human benign and malignant neoplastic lesions. In addition, KRAS mutations have also been reported in non-neoplastic tissues under chronic inflammatory conditions. Importantly, KRAS mutations have been reported in oncocytic sinonasal papillomas and sinonasal squamous cell carcinoma associated with oncocytic sinonasal papilloma and EGFR mutations have been reported in sinonasal adenocarcinoma, inverted sinonasal papilloma, and sinonasal squamous cell carcinoma associated with inverted sinonasal papilloma. The molecular pathogenesis of nasal polyps remains unclear. Therefore, the present study aimed to investigate the presence of KRAS, BRAF, and EGFR pathogenic mutations in CRSwNP. METHODS: Fourteen chronic rhinosinusitis-associated nasal polyp samples were direct sequenced, targeting KRAS exons 2, 3, and 4 (encompassing important hotspot mutations, including codons 12, 13, 61 and 146), BRAF exons 11 and 15, and EGFR exons 19 and 20. RESULTS: No pathogenic mutations were detected in the sequenced regions of KRAS, BRAF, and EGFR genes. CONCLUSION: This finding suggests that mutations in these genes are not a frequent event in CRSwNP, and, if they occur, they might represent marginal events at best.

Oral melanoacanthoma: Clinicopathological and immunohistochemical features of a case series and a scoping review.

BACKGROUND: This study presents a case series and scoping review of oral melanoacanthoma to examine its clinical, histopathological, and immunohistochemical characteristics. METHODS: Nine cases of oral melanoacanthoma were included in the case series. Clinical data were collected from biopsy charts. Hematoxylin-eosin and immunohistochemistry for TRP2, CD3, and CD20 were done. For the scoping review, MEDLINE/PubMed, Web of Science, EMBASE, and Scopus were searched. RESULTS: Case series: The mean age was 46.8 years (female-to-male ratio 2:1). Lesion's mean size was 11.0 mm (±9.3). Lesions were mainly macular (77.8%) with brown or black coloration (88.9%) and often affected multiple sites (44.4%). The evolution time ranged from 15 days to 96 months. Lesions commonly showed epithelial acanthosis (66.7%), spongiosis (55.6%), exocytosis (77.8%), melanin incontinence (88.9%), and inflammatory infiltrate in the lamina propria (77.8%), from which all showed lymphocytes. TRP2-positive melanocytes were identified in the basal and spinous layer of all cases, and in the superficial layer of three cases. CD3-positive cells predominate over the CD20-positive. Scoping review: 85 cases of oral melanoacanthoma were retrieved from 55 studies. Patients were primarily female (female-to-male ratio 2.2:1), black-skinned (64.1%), with a mean age of 36.13 (± 17.24). Lesions were flat (81.9%), often brown (62.4%). Buccal mucosa was the preferred site (32.9%), followed by multiple sites (28.2%). CONCLUSION: Oral melanoacanthoma mainly affects women across a wide age range, with lesions commonly appearing as brown/black macules, particularly on the buccal mucosa. TRP2-positive melanocytes and T-lymphocytes were consistently found and could participate in oral melanoacanthoma pathogenesis.

Can SARS-CoV-2 screening in oral biopsies aid epidemiological surveillance?

BACKGROUND: Three years after the first confirmed COVID-19 case in Brazil, the outcomes of Federal government omissions in managing the crisis and anti-science stance heading into the pandemic have become even more evident. With over 36 million confirmed cases and nearly 700 000 deaths up to January 2023, the country is one of the hardest-hit places in the world. The lack of mass-testing programs was a critical broken pillar responsible for the quick and uncontrolled SARS-CoV-2 spread throughout the Brazilian population. Faced with this situation, we aimed to perform the routine SARS-CoV-2 screening through RT-qPCR of oral biopsies samples to aid in the asymptomatic epidemiological surveillance during the principal outbreak periods. METHODS: We analyzed 649 formalin-fixed paraffin-embedded oral tissue samples from five important oral and maxillofacial pathology laboratories from the north, northeast, and southeast geographic regions of Brazil. We also sequenced the whole viral genome of positive cases to investigate SARS-CoV-2 variants. RESULTS: The virus was detected in 9/649 analyzed samples, of which three harbored the Variant of Concern Alpha (B.1.1.7). CONCLUSION: Although our approach did not value aiding asymptomatic epidemiological surveillance, we could successfully identify a using FFPE tissue samples. Therefore, we suggest using FFPE tissue samples from patients who have confirmed diagnosis of SARS-CoV-2 infection for phylogenetic reconstruction and contraindicate the routine laboratory screening of these samples as a tool for asymptomatic epidemiological surveillance.

De novo TRPV4 Leu619Pro variant causes a new channelopathy characterised by giant cell lesions of the jaws and skull, skeletal abnormalities and polyneuropathy.

BACKGROUND: Pathogenic germline variants in Transient Receptor Potential Vanilloid 4 Cation Channel (TRPV4) lead to channelopathies, which are phenotypically diverse and heterogeneous disorders grossly divided in neuromuscular disorders and skeletal dysplasia. We recently reported in sporadic giant cell lesions of the jaws (GCLJs) novel, somatic, heterozygous, gain-of-function mutations in TRPV4, at Met713. METHODS: Here we report two unrelated women with a de novo germline p.Leu619Pro TRPV4 variant and an overlapping systemic disorder affecting all organs individually described in TRPV4 channelopathies. RESULTS: From an early age, both patients had several lesions of the nervous system including progressive polyneuropathy, and multiple aggressive giant cell-rich lesions of the jaws and craniofacial/skull bones, and other skeletal lesions. One patient had a relatively milder disease phenotype possibly due to postzygotic somatic mosaicism. Indeed, the TRPV4 p.Leu619Pro variant was present at a lower frequency (variant allele frequency (VAF)=21.6%) than expected for a heterozygous variant as seen in the other proband, and showed variable regional frequency in the GCLJ (VAF ranging from 42% to 10%). In silico structural analysis suggests that the gain-of-function p.Leu619Pro alters the ion channel activity leading to constitutive ion leakage. CONCLUSION: Our findings define a novel polysystemic syndrome due to germline TRPV4 p.Leu619Pro and further extend the spectrum of TRPV4 channelopathies. They further highlight the convergence of TRPV4 mutations on different organ systems leading to complex phenotypes which are further mitigated by possible post-zygotic mosaicism. Treatment of this disorder is challenging, and surgical intervention of the GCLJ worsens the lesions, suggesting the future use of MEK inhibitors and TRPV4 antagonists as therapeutic modalities for unmet clinical needs.

Revisiting the human dental follicle: From tooth development to its association with unerupted or impacted teeth and pathological changes.

Dental follicles are involved in odontogenesis, periodontogenesis, and tooth eruption. Dental follicles are unique structures, considering that their remnants can persist within the jawbones after odontogenesis throughout life if the tooth does not erupt. Pathological changes may occur in these tissues as individuals age. The changes range from benign to life threatening. Thus, the assessment of age-related changes in dental follicles associated with unerupted teeth is of paramount importance. In this review, we summarize the physiological roles and changes in dental follicles in odontogenesis, tooth eruption, and aging, in addition to the pathological changes associated with these structures. We encourage investigators to consider this peculiar tissue as a unique model and explore its potential to clarify its importance from the viewpoints of developmental biology, tissue physiology, and pathology.

Promyelocytic leukemia protein is a restriction factor for Junín virus independently of Z matrix protein.

The New World (NW) mammarenavirus Junín (JUNV) is the etiological agent of Argentine hemorrhagic fever, a human endemic disease of Argentina. Promyelocytic leukemia protein (PML) has been reported as a restriction factor for several viruses although the mechanism/s behind PML-mediated antiviral effect may be diverse and are a matter of debate. Previous studies have reported a nuclear to cytoplasm translocation of PML during the murine Old World mammarenavirus lymphocytic choriomeningitis virus (LCMV) infection. This translocation was found to be mediated by the viral Z protein. Here, we show that PML restricts JUNV infection in human A549 cells. However, in contrast to LCVM, JUNV infection enhances PML expression and PML is not translocated to the cytoplasm neither it colocalizes with JUNV Z protein. Our study demonstrates that a NW mammarenavirus as JUNV interacts differently with the antiviral protein PML than LCMV.

Adenoid ameloblastoma harbors beta-catenin mutations.

Adenoid ameloblastoma is a very rare benign epithelial odontogenic tumor characterized microscopically by epithelium resembling conventional ameloblastoma, with additional duct-like structures, epithelial whorls, and cribriform architecture. Dentinoid deposits, clusters of clear cells, and ghost-cell keratinization may also be present. These tumors do not harbor BRAF or KRAS mutations and their molecular basis appears distinct from conventional ameloblastoma but remains unknown. We assessed CTNNB1 (beta-catenin) exon 3 mutations in a cohort of 11 samples of adenoid ameloblastomas from 9 patients. Two of the 9 patients were female and 7 male and in 7/9 patients the tumors occurred in the maxilla. Tumors of 4 of these 9 patients harbored CTNNB1 mutations, specifically p.Ser33Cys, p.Gly34Arg, and p.Ser37Phe. Notably, for one patient 3 samples were analyzed including the primary tumour and two consecutive recurrences, and results were positive for the mutation in all three tumors. Therefore, 6/11 samples tested positive for the mutation. In the 6 mutation-positive samples, ghost cells were present in only 2/6, indicating beta-catenin mutations are not always revealed by ghost cell formation. Dentinoid matrix deposition was observed in 5/6 mutation-positive samples and clear cells in all 6 cases. None of the cases harbored either BRAF or KRAS mutations. Beta-catenin immunoexpression was assessed in the samples of 8 patients. Except for one wild-type case, all cases showed focal nuclear expression irrespective of the mutational status. Together with the absence of BRAF mutation, the detection of beta-catenin mutation in adenoid ameloblastomas supports its classification as a separate entity, and not as a subtype of ameloblastoma. The presence of this mutation may help in the diagnosis of challenging cases.