Progenitor identification and SARS-CoV-2 infection in human distal lung organoids.

The distal lung contains terminal bronchioles and alveoli that facilitate gas exchange. Three-dimensional in vitro human distal lung culture systems would strongly facilitate the investigation of pathologies such as interstitial lung disease, cancer and coronavirus disease 2019 (COVID-19) pneumonia caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Here we describe the development of a long-term feeder-free, chemically defined culture system for distal lung progenitors as organoids derived from single adult human alveolar epithelial type II (AT2) or KRT5+ basal cells. AT2 organoids were able to differentiate into AT1 cells, and basal cell organoids developed lumens lined with differentiated club and ciliated cells. Single-cell analysis of KRT5+ cells in basal organoids revealed a distinct population of ITGA6+ITGB4+ mitotic cells, whose offspring further segregated into a TNFRSF12Ahi subfraction that comprised about ten per cent of KRT5+ basal cells. This subpopulation formed clusters within terminal bronchioles and exhibited enriched clonogenic organoid growth activity. We created distal lung organoids with apical-out polarity to present ACE2 on the exposed external surface, facilitating infection of AT2 and basal cultures with SARS-CoV-2 and identifying club cells as a target population. This long-term, feeder-free culture of human distal lung organoids, coupled with single-cell analysis, identifies functional heterogeneity among basal cells and establishes a facile in vitro organoid model of human distal lung infections, including COVID-19-associated pneumonia.

The Diagnostic Value of sTWEAK in Acute Ischemic Stroke

Background: Considering the critical role of early diagnosis and management of acute ischemic stroke, biomarkers that can reliable assist in the diagnosis are still needed. These biomarkers should rapidly analyze, have high specificity for brain damage, and be available in the emergency settings for early diagnosis and exclusion of other conditions that mimic acute ischemic stroke. Soluble tumor necrosis factor-like weak inducer of apoptosis, a protein involved in the regulation of several biological functions, could be a potential acute ischemic stroke biomarker. Aims: To investigate the diagnostic value of soluble tumor necrosis factor-like weak inducer of apoptosis in patients with acute ischemic stroke and examine the relationship between ischemic area volume determined at diffusion-weighted magnetic resonance imaging and soluble tumor necrosis factor-like weak inducer of apoptosis. Study Design: A prospective, case-control study. Methods: This case-control prospective study included 36 patients with acute ischemic stroke and 36 healthy volunteers. Information on age, sex, presence of chronic disease, neurological examination findings, times of presentation to the emergency department after acute ischemic stroke, soluble tumor necrosis factor-like weak inducer of apoptosis levels, ischemic area volumes at diffusion-weighted magnetic resonance imaging, and 6-month mortality rates after stroke were recorded. The results were analyzed on SPSS 22.0 software (SPSS Inc., Chicago, IL, USA), and p<0.05 was considered statistically significant. Results: A soluble tumor necrosis factor-like weak inducer of apoptosis cut-off value of 995.5 pg/mL exhibited a sensitivity of 80.5% and a positive predictive value of 82.5% with an area under the curve of 0.84 (95% confidence interval: 0.74-0.94; p<0.001). The mean soluble tumor necrosis factor-like weak inducer of apoptosis levels in the acute ischemic stroke group (1968.08±1441.99 µg/L) were significantly higher than those in the control group (704.81±291.72 µg/L) (p<0.001). No correlation was observed between soluble tumor necrosis factor-like weak inducer of apoptosis levels and ischemic area volume measured at diffusion-weighted magnetic resonance imaging (r=-0.008; p=0.07). The mean ischemic area volume was 505.68±381.10 and 60.96±80.89 mm3 in the nonsurviving and surviving patients, respectively (p=0.002). Conclusion: Soluble tumor necrosis factor-like weak inducer of apoptosis can be used in the diagnosis of acute ischemic stroke. However, it is inconclusive in estimating ischemic area volume and early mortality following acute ischemic stroke. Ischemic area volume measured at diffusion-weighted magnetic resonance imaging is a marker of poor prognosis and can be used in predicting early mortality.

CD1d is a novel cell-surface marker for human monocytic myeloid-derived suppressor cells with T cell suppression activity in peripheral blood after allogeneic hematopoietic stem cell transplantation.

Myeloid-derived suppressor cells (MDSCs) are a heterogeneous population of cells that regulate immune responses in cancer and various pathological conditions. However, the phenotypic and functional heterogeneity of human MDSCs represents a major hurdle for the development of therapeutic strategies targeting or regulating MDSCs in tumor progression, inflammation, and graft-versus-host disease (GVHD). We previously shown that circulating HLA-DR-CD14+ monocytic MDSCs are a major contributor to clinical outcomes after allogeneic hematopoietic stem cell transplantation (allo-HSCT). In this study, we identified, using high-throughput screening, a set of surface markers that are strongly expressed in HLA-DR-CD14+ monocytic MDSCs isolated from the peripheral blood (PB) of patients receiving allo-HSCT. Subsequent experiments showed the consistent dominant expression of CD1d in monocytic MDSCs of allo-HSCT PB in comparison with granulocytic MDSCs. In addition, CD1d-expressing cells isolated from PB of allo-HSCT patients showed the suppressive activity of T cell proliferation and higher expression of MyD88 and IDO compared with CD1d- cells. Our results suggest that CD1d could be a valuable marker for further therapeutic evaluation of human monocytic MDSCs for immune-related diseases, including GVHD.