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.

Quantitative analysis of ß1,6GlcNAc-branched N-glycans on ß4 integrin in cutaneous squamous cell carcinoma.

α6ß4 integrin plays pivotal roles in cancer progression in several types of cancers. Our previous study using N-glycan-manipulated cell lines demonstrated that defects in N-glycans or decreased ß1,6GlcNAc-branched N-glycans on ß4 integrin suppress ß4 integrin-mediated cancer cell adhesion, migration, invasion, and tumorigenesis. Furthermore, immunohistochemical analysis has shown that colocalization of ß1,6GlcNAc-branched N-glycans with ß4 integrin was observed in cutaneous squamous cell carcinoma (SCC) tissue. However, until now there has been no direct evidence that ß1,6GlcNAc-branched N-glycans are upregulated on ß4 integrin in cutaneous SCC. In the present study, we performed an ELISA analysis of ß1,6GlcNAc-branched N-glycans on ß4 integrins as well as ß4 integrins in cell lysates from human normal skin and cutaneous SCC tissues. The SCC samples showed a 4.9- to 7.4-fold increase in the ratio of ß1,6GlcNAc-branched N-glycans to ß4 integrin compared with normal skin samples. These findings suggest that the addition of ß1,6GlcNAc-branched N-glycans onto ß4 integrin was markedly elevated in cutaneous SCC tissue compared to normal skin tissue. The value of ß1,6GlcNAc-branched N-glycans on ß4 integrin may be useful as a diagnostic marker associated with cutaneous SCC tumor progression.

Integrin ß4 Is an Effective and Efficient Marker in Synchronously Highlighting Lymphatic and Blood Vascular Invasion, and Perineural Aggression in Malignancy.

Lymphovascular invasion (LVI) and perineural invasion (PNI) are 2 important pathologic parameters and need to be accurately assessed in multiple malignancies. Integrin ß4, a member of the integrin family, has been reported to be positively expressed in vascular endothelia, peripheral nerves, and a collection of epithelia. However, little is known about the effectiveness of ß4 immunostaining on the recognition of LVI and PNI. Herein, we explored the applicability of ß4 immunostaining in stomach, thyroid, and breast cancers. Parallel immunostaining of D2-40, CD34, and S-100 was performed as controls for lymphatic endothelia, vascular endothelia, and neural fibers, respectively. The results demonstrated that ß4 concurrently stained the lymphatic and vascular endothelia, and the peripheral nerves. Both LVI and PNI were clearly and accurately outlined by ß4 immunostaining. ß4 was also expressed in the majority of tumor cells, enabling recognition of LVI and PNI encroached by small tumor clusters. In contrast to D2-40 and CD34, ß4 staining was not observed in stromal cells, and therefore it facilitated differentiation between the shrinkage cleft and LVI. According to our results, ß4 staining strikingly increased the diagnostic accuracy and interobserver concordance for LVI and PNI compared with hematoxylin and eosin staining alone. Finally, the applicability of ß4 was confirmed in 9 other types of malignancies, including cancers of the colon, prostate, esophagus, lung, kidney, uterus, tongue, bladder, and liver. Collectively, ß4 is a reliable marker for synchronous detection and diagnosis of LVI and PNI.

Cytotoxic tumour-infiltrating T lymphocytes influence outcome in resected pancreatic ductal adenocarcinoma.

BACKGROUND: We studied the prognostic effect of CD3-, CD8- and CD103-positive T lymphocytes in a cohort of 165 patients with resected pancreatic ductal adenocarcinomas (PDACs) of the treatment group (adjuvant gemcitabine) and the untreated control group of the CONKO-001 study. METHODS: Immunohistochemical stainings on tissue microarrays (TMAs) against CD3, CD8 and CD103 were performed according to standard procedures. RESULTS: A high number of CD8-positive lymphocytes were significantly and independently associated with longer disease-free survival (DFS) and overall survival (OS) in the overall study population. Median DFS/OS were 7.4/18.1 months for patients with a low number of CD8-positive intratumoural lymphocytes (≤42 per 1 mm tissue core) and 12.7/25.2 months for patients with high numbers (>42 per 1-mm tissue core; p = 0.008/0.020; HR 0.62/0.65). The ratio of intraepithelial to total CD103-positive lymphocytes, but not total numbers of CD103-positive lymphocytes or CD103-positive intraepithelial lymphocytes, was associated with significantly improved DFS and OS in the overall study population (p = 0.022/0.009). Median DFS/OS was 5.9/15.7 for patients with a ratio of intraepithelial to total CD103-positive intratumoural lymphocytes higher than 0.3 and 11.6/24.7 for patients with a lower ratio. CONCLUSION: T-lymphocyte subpopulations might be prognostic in resectable PDAC but need standardization and verification by further studies.

Efficiency and Specificity of Gene Deletion in Lung Epithelial Doxycycline-Inducible Cre Mice.

The transgenic mouse strains surfactant protein C-reverse tetracycline transactivator (SP-C-rtTA), club cell secretory protein (CCSP)-rtTA, and tetracycline operator (TetO)-Cre have been invaluable for spatiotemporally regulating gene deletion in the pulmonary epithelium. In this study, we measured the efficiency and specificity of gene deletion that can be achieved in these mice using the Rosa26-eYFP reporter. Triple-transgenic mice (tTg or rtTA/TetO-Cre/Rosa-eYFP) were bred and treated with various doxycycline (dox) regimens to induce gene deletion, which was then quantified in various cell populations by flow cytometry. In these crosses, we found that the TetO-Cre transgene must be transmitted through the female parent to avoid germline gene deletion. With dox exposure during lung development, SP-C-tTg mice deleted in ∼65-75% of alveolar epithelial type II (ATII) cells, but in only ∼45-50% of the integrin ß4+ population, which consisted of club cells and distal lung progenitor cells. In contrast, CCSP-tTg mice deleted in ∼50% of ATII cells and ∼80% of integrin ß4+ cells. Upon dox treatment of adults, deletion in ATII cells and integrin ß4+ cells in SP-C-tTg mice dropped significantly to ∼20% and ∼6%, respectively, whereas CCSP-tTg mice deleted in ∼57% of ATII and ∼40% of integrin ß4+ cells. Interestingly, untreated CCSP-tTg mice also deleted in ∼40% of integrin ß4+ cells, indicating significant leakiness of CCSP-tTg in ß4+ cells. In all mouse groups, minimal deletion occurred in mouse tracheal epithelial cells or in mesenchymal or hematopoietic cells. These data provide the first quantitative, side-by-side comparison of the deletion efficiency for these widely used transgenic mouse strains.

Elevated integrin α6ß4 expression is associated with venous invasion and decreased overall survival in non-small cell lung cancer.

Lung cancer carries a poor prognosis and is the most common cause of cancer-related death worldwide. The integrin α6ß4, a laminin receptor, promotes carcinoma progression in part by cooperating with various growth factor receptors to facilitate invasion and metastasis. In carcinoma cells with mutant TP53, the integrin α6ß4 promotes cell survival. TP53 mutations and integrin α6ß4 overexpression co-occur in many aggressive malignancies. Because of the high frequency of TP53 mutations in lung squamous cell carcinoma (SCC), we sought to investigate the association of integrin ß4 expression with clinicopathologic features and survival in non-small cell lung cancer (NSCLC). We constructed a lung cancer tissue microarray and stained sections for integrin ß4 subunit expression using immunohistochemistry. We found that integrin ß4 expression is elevated in SCC compared with adenocarcinoma (P<.0001), which was confirmed in external gene expression data sets (P<.0001). We also determined that integrin ß4 overexpression associates with the presence of venous invasion (P=.0048) and with reduced overall patient survival (hazard ratio, 1.46; 95% confidence interval, 1.01-2.09; P=.0422). Elevated integrin ß4 expression was also shown to associate with reduced overall survival in lung cancer gene expression data sets (hazard ratio, 1.49; 95% confidence interval, 1.31-1.69; P<.0001). Using cBioPortal, we generated a network map demonstrating the 50 most highly altered genes neighboring ITGB4 in SCC, which included laminins, collagens, CD151, genes in the EGFR and PI3K pathways, and other known signaling partners. In conclusion, we demonstrate that integrin ß4 is overexpressed in NSCLC where it is an adverse prognostic marker.

MUC5AC interactions with integrin ß4 enhances the migration of lung cancer cells through FAK signaling.

MUC5AC is a secretory mucin aberrantly expressed in various cancers. In lung cancer, MUC5AC is overexpressed in both primary and metastatic lesions; however, its functional role is not well understood. The present study was aimed at evaluating mechanistic role of MUC5AC on metastasis of lung cancer cells. Clinically, the overexpression of MUC5AC was observed in lung cancer patient tissues and was associated with poor survival. In addition, the overexpression of Muc5ac was also observed in genetically engineered mouse lung adenocarcinoma tissues (Kras(G12D); Trp53(R172H/+); AdCre) in comparison with normal lung tissues. Our functional studies showed that MUC5AC knockdown resulted in significantly decreased migration in two lung cancer cell lines (A549 and H1437) as compared with scramble cells. Expression of integrins (α5, ß1, ß3, ß4 and ß5) was decreased in MUC5AC knockdown cells. As both integrins and MUC5AC have a von Willebrand factor domain, we assessed for possible interaction of MUC5AC and integrins in lung cancer cells. MUC5AC strongly interacted only with integrin ß4. The co-localization of MUC5AC and integrin ß4 was observed both in A549 lung cancer cells as well as genetically engineered mouse adenocarcinoma tissues. Activated integrins recruit focal adhesion kinase (FAK) that mediates metastatic downstream signaling pathways. Phosphorylation of FAK (Y397) was decreased in MUC5AC knockdown cells. MUC5AC/integrin ß4/FAK-mediated lung cancer cell migration was confirmed through experiments utilizing a phosphorylation (Y397)-specific FAK inhibitor. In conclusion, overexpression of MUC5AC is a poor prognostic marker in lung cancer. MUC5AC interacts with integrin ß4 that mediates phosphorylation of FAK at Y397 leading to lung cancer cell migration.

Splicing abnormality of integrin ß4 gene (ITGB4) due to nucleotide substitutions far from splice site underlies pyloric atresia-junctional epidermolysis bullosa syndrome.

BACKGROUND: Pyloric atresia-junctional epidermolysis bullosa syndrome (PA-JEB) is a rare subgroup of epidermolysis bullosa, which is inherited disorder characterized by skin fragile. PA-JEB is caused by mutation of ITGB4 or ITGA6, which encodes integrin ß4 or α6, respectively. OBJECTIVE: To clarify the molecular basis of PA-JEB and to expand the mutational database, we carried out the mutational analysis of a 29-year-old Japanese PA-JEB patient. METHODS: Standard methods were used to prepare, PCR-amplify, and sequence DNA or mRNA in peripheral blood or skin samples, respectively. RESULTS: Sequence analysis revealed two novel mutations in ITGB4, c.264+2TtoA and c.1762-25TtoA. The paternal c.264+2TtoA resided within a splice site consensus region and generated two splice variants resulting in a premature termination codon (PTC). The maternal c.1762-25TtoA was a unique mutation because of its location, 25 bp away from the splice site, and resided in branch-point consensus sequence. This c.1762-25TtoA substitution resulted in generation of two abnormal transcripts each with a PTC. Genotype-phenotype correlation in this case was also unique because the proband showed a non-lethal phenotype regardless of both mutations resulted in only abnormal transcripts with a PTC. CONCLUSION: The present case expands the mutational database and further elucidates the genotype-phenotype correlation for this rare disease, PA-JEB.

Clonal culture of adult mouse lung epithelial stem/progenitor cells.

Clonal culture of stem cells is crucial for their identification, and the characterization of the cellular and molecular mechanisms that regulate their proliferation and differentiation. In the adult mouse lung, epithelial stem/progenitor cells are defined by the phenotype CD45(neg) CD31(neg) EpCAM(pos) CD104(pos) CD24(low). Here we describe a tissue dissociation and flow cytometry strategy for the detection and isolation of adult mouse lung epithelial stem/progenitor cells, and a three-dimensional colony-forming assay for their clonal culture in vitro.

The role of phosphoinositide 3-kinase in adhesion of oral epithelial cells to titanium.

BACKGROUND: Oral epithelial cells (OECs) adhesion to titanium may improve the success rate of implant restoration. PURPOSE: We investigated the mechanism by which OECs adhere to titanium dental implants. MATERIALS AND METHODS: (1) After culturing rat OECs on titanium plates (Ti) or culture dishes in the presence or absence of a phosphoinositide 3-kinase (PI3K) activator or inhibitors and/or growth factors, and OEC morphology under these conditions were analyzed. (2) Right maxillary first molars were extracted and replaced with experimental implants. The rats were treated with or without growth factors. RESULTS: (1) Cell adherence was lower of OECs on Ti than in those on culture dishes, as were the levels of integrin ß4 and the continuity of F-actin structures. After PI3K inhibition, markedly reducing adherence to both substrates. In contrast, PI3K activation with activator or insulin-like growth factor restored the OEC adherence and the expression of adhesion molecules on Ti to the levels seen in OECs cultured on dishes. Cell migration was inhibited by PI3K activation. (2) High expression of integrin ß4 was observed in the peri-implant epithelia of PI3K-activated rats. CONCLUSION: These findings suggest that PI3K plays an important role in the adhesion of OECs to Ti.