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Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is not always confined to the respiratory system, as it impacts people on a broad clinical spectrum from asymptomatic to severe systemic manifestations resulting in death. Further, accumulation of intra-host single nucleotide variants during prolonged SARS-CoV-2 infection may lead to emergence of variants of concern (VOCs). Still, information on virus infectivity and intra-host evolution across organs is sparse. We report a detailed virological analysis of thirteen postmortem coronavirus disease 2019 (COVID-19) cases that provides proof of viremia and presence of replication-competent SARS-CoV-2 in extrapulmonary organs of immunocompromised patients, including heart, kidney, liver, and spleen (NCT04366882). In parallel, we identify organ-specific SARS-CoV-2 genome diversity and mutations of concern N501Y, T1027I, and Y453F, while the patient had died long before reported emergence of VOCs. These mutations appear in multiple organs and replicate in Vero E6 cells, highlighting their infectivity. Finally, we show two stages of fatal disease evolution based on disease duration and viral loads in lungs and plasma. Our results provide insights about the pathogenesis and intra-host evolution of SARS-CoV-2 and show that COVID-19 treatment and hygiene measures need to be tailored to specific needs of immunocompromised patients, even when respiratory symptoms cease. Here the authors provide a detailed virological analysis of thirteen postmortem COVID-19 cases, including presence of replication-competent SARS-CoV-2 in extrapulmonary organs and tissue-specific patterns of SARS-CoV-2 genome diversity of an immunocompromised patient.

RNF43 is an important negative regulator of β-catenin signaling by removing Wnt-receptors from the membrane. It is often mutated in cancers, leading to aberrant Wnt-dependent nuclear translocation of β-catenin. RNF43 has also been suggested to regulate β-catenin signaling directly within the nucleus, among other proposed nuclear functions. Given the importance of RNF43 in regulating Wnt/β-catenin signaling and its potential therapeutic relevance, a proper understanding of RNF43 biology is required. However, the presumed nuclear location is mainly based on available antibodies. These same antibodies have also been used extensively for immunoblotting or immunohistochemical purposes. However, a proper evaluation of their quality to reliably detect endogenous RNF43 has not been performed. Here, using genome editing we have generated a cell line that entirely misses RNF43 exons 8 and 9, encoding the epitopes of commonly used RNF43 antibodies. Using this clone in addition to various other cell line tools, we show that four RNF43 antibodies only yield non-specific signals when applied in immunoblotting, immunofluorescence and immunohistochemical experiments. In other words, they cannot reliably detect endogenous RNF43. Our results suggest that the nuclear staining patterns are an antibody artifact and that RNF43 is unlikely to localize within the nucleus. More generally, reports using RNF43 antibodies should be interpreted with caution, at least for the RNF43 protein aspects described in these papers.

Abstract The expression of the matricellular protein periostin has been associated with glioma progression. In previous work we found an association of periostin with glioma angiogenesis. Here, we screen gliomas for POSTN expression and identify the cells that express periostin in human gliomas. In addition, we study the role of periostin in an in vitro model for angiogenesis. The expression of periostin was investigated by RT-PCR and by immunohistochemistry. In addition, we used double labeling and in situ RNA techniques to identify the expressing cells. To investigate the function of periostin, we silenced POSTN in a 3D in vitro angiogenesis model. Periostin expression was elevated in pilocytic astrocytoma and glioblastoma, but not in grade II/III astrocytomas and oligodendrogliomas. The expression of periostin colocalized with PDGFRβ+ cells, but not with OLIG2+/SOX2+ glioma stem cells. Silencing of periostin in pericytes in coculture experiments resulted in attenuation of the numbers and the length of the vessels formation and in a decrease in endothelial junction formation. We conclude that pericytes are the main source of periostin in human gliomas and that periostin plays an essential role in the growth and branching of blood vessels. Therefore, periostin should be explored as a novel target for developing anti-angiogenic therapy for glioma.

According to conventional views, colon cancer originates from stem cells. However, inflammation, a key risk factor for colon cancer, has been shown to suppress intestinal stemness. Here, we used Paneth cells as a model to assess the capacity of differentiated lineages to trigger tumorigenesis in the context of inflammation in mice. Upon inflammation, Paneth cell-specific Apc mutations led to intestinal tumors reminiscent not only of those arising in patients with inflammatory bowel disease, but also of a larger fraction of human sporadic colon cancers. The latter is possibly because of the inflammatory consequences of western-style dietary habits, a major colon cancer risk factor. Machine learning methods designed to predict the cell-of-origin of cancer from patient-derived tumor samples confirmed that, in a substantial fraction of sporadic cases, the origins of colon cancer reside in secretory lineages and not in stem cells. Upon inflammation and targeted gene mutation, some fully differentiated secretory and postmitotic intestinal epithelial lineages dedifferentiate to acquire stem-like features and promote tumor formation.

Kidney transplantation is the optimal treatment for patients with end-stage kidney disease. Donor-specific urinary extracellular vesicles (uEVs) hold potential as biomarkers for assessing allograft status. We aimed to develop a method for identifying donor-specific uEVs based on human leukocyte antigen (HLA) mismatching with the kidney transplant recipients (KTRs). Urine and plasma were obtained from HLA-A2+ donors and HLA-A2- KTRs pre-transplant. CD9 (tetraspanin, EV marker) and HLA-A2 double-positive (CD9+ HLA-A2+) EVs were quantified using isolation-free imaging flow cytometry (IFCM). Healthy individuals' urine was used to investigate CD9+ HLA-class-I+ uEV quantification using IFCM, time-resolved fluoroimmunoassay (TR-FIA), and immunogold staining cryo-electron microscopy (cryo-EM). Culture-derived CD9+ HLA-class-I+ EVs were spiked into the urine to investigate urine matrix effects on uEV HLA detection. Deceased donor kidneys and peritumoral kidney tissue were used for HLA class I detection with histochemistry. The concentrations of CD9+ HLA-A2+ EVs in both donor and recipient urine approached the negative (detergent-treated) control levels for IFCM and were significantly lower than those observed in donor plasma. In parallel, universal HLA class I+ uEVs were similarly undetectable in the urine and uEV isolates compared with plasma, as verified by IFCM, TR-FIA, and cryogenic electron microscopy. Culture supernatant containing HLA class I+ vesicles from B, T, and human proximal tubule cells were spiked into the urine, and these EVs remained stable at 37°C for 8 hours. Immunohistochemistry revealed that HLA class I was predominantly expressed on the basolateral side of renal tubules, with limited expression on their urine/apical side. The detection of donor-specific uEVs is hindered by the limited release of HLA class I+ EVs from the kidney into the urine, primarily due to the polarized HLA class I expression on renal tubules. Identifying donor-specific uEVs requires further advancements in recognizing transplant-specific uEVs and urine-associated markers.

Radiotherapy in the head-and-neck area is one of the main curative treatment options. However, this comes at the cost of varying levels of normal tissue toxicity, affecting up to 80% of patients. Mucositis can cause pain, weight loss and treatment delays, leading to worse outcomes and a decreased quality of life. Therefore, there is an urgent need for an approach to predicting normal mucosal responses in patients prior to treatment. We here describe an assay to detect irradiation responses in healthy oral mucosa tissue. Mucosa specimens from the oral cavity were obtained after surgical resection, cut into thin slices, irradiated and cultured for three days. Seven samples were irradiated with X-ray, and three additional samples were irradiated with both X-ray and protons. Healthy oral mucosa tissue slices maintained normal morphology and viability for three days. We measured a dose-dependent response to X-ray irradiation and compared X-ray and proton irradiation in the same mucosa sample using standardized automated image analysis. Furthermore, increased levels of inflammation-inducing factors—major drivers of mucositis development—could be detected after irradiation. This model can be utilized for investigating mechanistic aspects of mucositis development and can be developed into an assay to predict radiation-induced toxicity in normal mucosa.

Uveal melanoma is a lethal cancer with a strong propensity to metastasize. Limited therapeutic options are available once the disease has disseminated. A strong predictor for metastasis is the loss of chromosome 3. Inactivating mutations in BAP1 encoding the BRCA1-associated protein 1 and located on chromosome 3p21.1, have been described in uveal melanoma and other types of cancer. In this study, we determined the prevalence of somatic BAP1 mutations and examined whether these mutations correlate with the functional expression of BAP1 in uveal melanoma tissue and with other clinical, histopathological and chromosomal parameters. We screened a cohort of 74 uveal melanomas for BAP1 mutations, using different deep sequencing methods. The frequency of BAP1 mutations in our study group was 47%. The expression of BAP1 protein was studied using immunohistochemistry. BAP1 staining was absent in 43% of the cases. BAP1 mutation status was strongly associated with BAP1 protein expression (P<0.001), loss of chromosome 3 (P<0.001), and other aggressive prognostic factors. Patients with a BAP1 mutation and absent BAP1 expression had an almost eightfold higher chance of developing metastases compared with those without these changes (P=0.002). We found a strong correlation between the immunohistochemical and sequencing data and therefore propose that, immunohistochemical screening for BAP1 should become routine in the histopathological work-up of uveal melanoma. Furthermore, our analysis indicates that loss of BAP1 may be particularly involved in the progression of uveal melanoma to an aggressive, metastatic phenotype.

Granulomatous disease affects up to 20% of patients with Common Variable Immunodeficiency (CVID). Granulomas are comprised of highly activated immune cells, and emerge in response to antigenic triggers. In CVID granulomas however, the underlying pathophysiology is unclear and the specific trigger remains unknown. Granuloma formation in CVID is often compared to sarcoidosis, although clinical context and prognosis differ, suggesting a different pathogenesis. The aim of this study was to investigate if the cellular organization and proteomics of granulomas in CVID is different from other granulomatous diseases. Therefore, tissue slides from formaldehyde fixed paraffin embedded biopsies obtained from patients with CVID, sarcoidosis, tuberculosis and foreign-material induced pseudo-sarcoidosis were stained with hematoxylin and eosin and assessed for histopathological characteristics. Targeted spatial protein analysis was performed, and immune fluorescent multiplex assays were used to analyze the cellular organization. Histological analysis revealed that CVID granulomas were smaller, less circumscribed, with fewer multinucleated giant cells and minimal fibrosis compared to the other granulomatous diseases. Spatial protein analysis showed that granulomas in all diseases expressed CD68, CD11c, CD44, CD127, and PD-L1. However in CVID, reduced expression of the fibrosis-related protein fibronectin, but enrichment of CD163, CD3 and FAPα inside CVID granulomas was observed. Immunofluorescence analysis conformed a different cellular organization in CVID granulomas with increased influx of neutrophils, macrophages, T and B lymphocytes. In conclusion, granulomas in CVID display a different histological and cellular organization with increased influx of myeloid and lymphoid cells, compared to sarcoidosis, tuberculosis and pseudo-sarcoidosis, indicating a distinct pathogenesis underlying granuloma formation.

Background Kidney injury, typically accompanied by inflammation, is a driver for kidney fibrosis, which contributes to the development of kidney failure. Mesenchymal stromal cells (MSC) have been proposed to have anti-fibrotic potential, but challenges such as their short persistence after infusion and inability to cross the lung capillary system due to their large size hamper their use for treatment of kidney fibrosis. It is hypothesized that the effects of MSC are partially dependent on phagocytosis of fragments of MSC by target cells and inhibiting excessive immune activation response. To exploit this effect of MSC, we developed nanosized membrane particles (MP) from MSC and explored their anti-fibrotic activity and immunomodulation effect in mouse and human kidney fibrosis models. Methods MP were generated from culture-expanded MSC through extrusion of isolated membranes. Unilateral kidney ischemia reperfusion injury (IRI) in male Balb/c mice was used to induce kidney fibrosis. MP generated from 1 × 10 6 MSC were injected in the tail vein immediately after anesthesia recovery. In a second model, human induced pluripotent stem cell-derived kidney organoids were exposed to 1% O 2 for 48 h and 100 ng/mL IL-1β for 96 h to mimic IRI in vitro for inducing fibrosis. MP generated from 0.5 × 10 6 MSC were added to the medium for 4 consecutive days. Fibrosis and immune cell markers were subsequently measured. Results IRI induced the expression of transforming growth factor beta (TGFβ) and collagen type I alpha 1(COL1A1) in mouse kidneys. MP treatment significantly reduced TGF-β mRNA at day 3 while COL1A1 mRNA and protein were downregulated at day 7. We found no evidence for an immunomodulatory effect of MP, as the number and activity of infiltrating T cells and macrophages did not change. In kidney organoids, a rise in COL1A1 and TGF-β demonstrated successful fibrosis induction by hypoxia and IL-1β. MP significantly decreased these fibrosis markers. Additionally, immunohistochemistry revealed a reduction in the myofibroblast marker alpha smooth muscle actin. Conclusions Our results demonstrate that MP have anti-fibrotic properties in mouse kidney IRI and human kidney organoid models. These results indicate that MP have potential for the development of kidney fibrosis-inhibiting therapy.

Introduction Accessory cavitated uterine malformation (ACUM) is a relatively recent term used to describe a noncommunicating, accessory uterine cavity. ACUM have been published under different terms ranging from juvenile cystic adenomyosis to “uterus‐like mass”. The objective of this study was to systematically identify all cases of ACUM and definitions described in the literature, regardless of label, and identify morphological, epidemiological, and clinical characteristics as well as management, while also highlighting knowledge gaps. Material and methods A systematic literature search of three databases was performed, reviewing all records of cystic myometrial lesions. Cases that fitted common definitions for ACUM were included and clinical and imaging characteristics were documented in detail. This work was registered to PROSPERO and reporting followed PRISMA guidelines for scoping reviews. Results A total of 53 articles were included, comprising 115 cases that met the minimal criteria for ACUM. The median age at onset of symptoms was 17 years, presenting with dysmenorrhea soon after menarche. A total of 19 women were parous. On ultrasound, ACUM appears as unilocular myometrial cysts, usually with ground‐glass content. Hemorrhagic content is also observed on magnetic resonance imaging (MRI), with high signal intensity on both T2 and T1‐weighted images. Ninety‐five (83%) cases were managed surgically, with a trend towards primary nonsurgical options. Although no adverse outcomes were reported, long‐term follow‐up on subsequent fertility and pregnancy was rare. Conclusions Despite its increasing recognition as a clinical entity, ACUM often remains underdiagnosed as it shares similarities with other myometrial masses. We propose a unified terminology and definition for ACUM based on the data in this review. ACUM presents as a cavitated lesion, surrounded by a myometrial mantle, in continuity with the anterolateral uterine wall and located beneath the insertion of the round ligament and the interstitial portion of the fallopian tube. In contrast to other uterine abnormalities, a normal uterine cavity is visualized. Future studies are needed, using a clear definition for ACUM, and prospectively investigating management strategies, including long‐term follow‐up of patient‐reported symptoms, fertility, and pregnancy outcomes. Accessory cavitated uterine malformation is a distinct, yet unclassified uterine anomaly. This systematic review summarizes diagnostic and clinical findings as well as management strategies from all described cases in the literature and suggests unified diagnostic criteria and definitions.