Overexpression of Desmoglein 2 in a mouse model of Gorlin syndrome enhances spontaneous basal cell carcinoma formation through STAT3-mediated Gli1 expression

Activation of the Hedgehog (Hh) pathway is causative of virtually all sporadic and Gorlin syndrome-related basal cell carcinomas (BCC), with loss of function of Patched1 (Ptc1) being the most common genomic lesion. Sporadic BCCs also overexpress desmoglein-2 (Dsg2), a desmosomal cadherin normally found in the basal layer. Using a mouse model of Gorlin syndrome (Ptc1+/lacZ mice), we found that overexpressing Dsg2 in the basal layer (K14-Dsg2/Ptc1+/lacZ) or the superficial epidermis (Inv-Dsg2/Ptc1+/lacZ mice) resulted in increased spontaneous BCC formation at 3 and 6 months, respectively. The tumors did not show loss of heterozygosity of Ptc1, despite high levels of Gli1 and phosphorylated Stat3. A panel of sporadic human BCCs showed increased staining of both Dsg2 and P-Stat3 in 9/9 samples. Overexpression of Dsg2 in ASZ001 cells, a Ptc1-/- BCC cell line, induced Stat3 phosphorylation and further increased Gli1 levels, both in an autocrine and paracrine manner. Three different Stat3 inhibitors reduced viability and Gli1 expression in ASZ001 cells, but not in HaCaT cells. Conversely, stimulation of Stat3 in ASZ001 cells with IL-6 increased Gli1 expression. Our results indicate that Dsg2 enhances canonical Hh signaling downstream of Ptc1 to promote BCC development through the activation of P-Stat3 and regulation of Gli1 expression

Antibiotic resistance patterns in Escherichia coli from gulls in nine European countries

Background: The prevalence of antibiotic resistant faecal indicator bacteria from humans and food production animals has increased over the last decades. In Europe, resistance levels in Escherichia coli from these sources show a south-to-north gradient, with more widespread resistance in the Mediterranean region compared to northern Europe. Recent studies show that resistance levels can be high also in wildlife, but it is unknown to what extent resistance levels in nature conform to the patterns observed in human-associated bacteria. Methods: To test this, we collected 3,158 faecal samples from breeding gulls (Larus sp.) from nine European countries and tested 2,210 randomly isolated E. coli for resistance against 10 antibiotics commonly used in human and veterinary medicine. Results: Overall, 31.5% of the gull E. coli isolates were resistant to ]1 antibiotic, but with considerable variation between countries: highest levels of isolates resistant to ]1 antibiotic were observed in Spain (61.2%) and lowest levels in Denmark (8.3%). For each tested antibiotic, the Iberian countries were either the countries with the highest levels or in the upper range in between-country comparisons, while northern countries generally had a lower proportion of resistant E. coli isolates, thereby resembling the gradient of resistance seen in human and food animal sources. Conclusion: We propose that gulls may serve as a sentinel of environmental levels of antibiotic resistant E. coli to complement studies of human-associated microbiota.Swedish Research Council FORMASThe Karin Korsner’s FoundationThe Olle Engkvist Byggma¨stare FoundationAD 22/01/201

Quantitative models of in vitro bacteriophage-host dynamics and their application to phage therapy

Phage therapy is the use of bacteriophages as antimicrobial agents for the control of pathogenic and other problem bacteria. It has previously been argued that successful application of phage therapy requires a good understanding of the non-linear kinetics of phage-bacteria interactions. Here we combine experimental and modelling approaches to make a detailed examination of such kinetics for the important food-borne pathogen Campylobacter jejuni and a suitable virulent phage in an in vitro system. Phage-insensitive populations of C. jejuni arise readily, and as far as we are aware this is the first phage therapy study to test, against in vitro data, models for phage-bacteria interactions incorporating phage-insensitive or resistant bacteria. We find that even an apparently simplistic model fits the data surprisingly well, and we confirm that the so-called inundation and proliferation thresholds are likely to be of considerable practical importance to phage therapy. We fit the model to time series data in order to estimate thresholds and rate constants directly. A comparison of the fit for each culture reveals density-dependent features of phage infectivity that are worthy of further investigation. Our results illustrate how insight from empirical studies can be greatly enhanced by the use of kinetic models: such combined studies of in vitro systems are likely to be an essential precursor to building a meaningful picture of the kinetic properties of in vivo phage therapy

A three-dimensional model of human lung development and disease from pluripotent stem cells

Author ManuscriptRecapitulation of lung development from human pluripotent stem cells (hPSCs) in three dimensions (3D) would allow deeper insight into human development, as well as the development of innovative strategies for disease modelling, drug discovery and regenerative medicine. We report here the generation from hPSCs of lung bud organoids (LBOs) that contain mesoderm and pulmonary endoderm and develop into branching airway and early alveolar structures after xenotransplantation and in Matrigel 3D culture. Expression analysis and structural features indicated that the branching structures reached the second trimester of human gestation. Infection in vitro with respiratory syncytial virus, which causes small airway obstruction and bronchiolitis in infants, led to swelling, detachment and shedding of infected cells into the organoid lumens, similar to what has been observed in human lungs. Introduction of mutation in HPS1, which causes an early-onset form of intractable pulmonary fibrosis, led to accumulation of extracellular matrix and mesenchymal cells, suggesting the potential use of this model to recapitulate fibrotic lung disease in vitro. LBOs therefore recapitulate lung development and may provide a useful tool to model lung disease.NIH HL120046-01 (H.-W.S.), 1U01HL134760-01 (H.-W.S.) RO1 AI031971 (A.M.), and RO1 AI114736 (A.M.), as well as a sponsored research and agreement from Northern Biologics Inc. (H.-W.S.), and funding from the Thomas R Kully IPF Research Fund (H.-W.S.). RUES2-HPS1 cells were generated by the Columbia Stem Cell Core Facility. We thank NYULMC OCS Microscopy core C. Petzold and K. Dancel for their assistance with transmission electron microscopy. We thank M. Peeples (Ohio State University) for providing the original recombinant RSV. Flow cytometry was performed in the CCTI Flow Cytometry Core, supported in part by the Office of the Director, National Institutes of Health under awards S10RR027050 and S10OD02005