Defined conditions for propagation and manipulation of mouse embryonic stem cells.

The power of mouse embryonic stem (ES) cells to colonise the developing embryo has revolutionised mammalian developmental genetics and stem cell research. This power is vulnerable, however, to the cell culture environment, deficiencies in which can lead to cellular heterogeneity, adaptive phenotypes, epigenetic aberrations and genetic abnormalities. Here, we provide detailed methodologies for derivation, propagation, genetic modification and primary differentiation of ES cells in 2i or 2i+LIF media without serum or undefined serum substitutes. Implemented diligently, these procedures minimise variability and deviation, thereby improving the efficiency, reproducibility and biological validity of ES cell experimentation.The funding statement is uploaded separately from the manuscript but the authors acknowledged Wellcome Trust, BBSRC and MRC. Austin Smith is an MRC Professor

Complementary Activity of ETV5, RBPJ, and TCF3 Drives Formative Transition from Naive Pluripotency.

The gene regulatory network (GRN) of naive mouse embryonic stem cells (ESCs) must be reconfigured to enable lineage commitment. TCF3 sanctions rewiring by suppressing components of the ESC transcription factor circuitry. However, TCF3 depletion only delays and does not prevent transition to formative pluripotency. Here, we delineate additional contributions of the ETS-family transcription factor ETV5 and the repressor RBPJ. In response to ERK signaling, ETV5 switches activity from supporting self-renewal and undergoes genome relocation linked to commissioning of enhancers activated in formative epiblast. Independent upregulation of RBPJ prevents re-expression of potent naive factors, TBX3 and NANOG, to secure exit from the naive state. Triple deletion of Etv5, Rbpj, and Tcf3 disables ESCs, such that they remain largely undifferentiated and locked in self-renewal, even in the presence of differentiation stimuli. Thus, genetic elimination of three complementary drivers of network transition stalls developmental progression, emulating environmental insulation by small-molecule inhibitors.This research was funded by the Wellcome Trust, the Biotechnology and Biological Sciences Research Council, European Commission (contract no. 200720, EuroSyStem) and the Louis Jeantet Foundation. The Cambridge Stem Cell Institute receives core support from the Wellcome Trust and the Medical Research Council. AS is a Medical Research Council Professor

A methodological approach for the identification of sulphate sources in the Portoscuso area (south-western Sardinia)

Several detrimental effects due to intense industrial activities affect the groundwater of the Portoscuso area (SW Sardinia, Italy) such that the Italian Government has designed the whole territory as a contaminated site of national interest (D.M., March 12, 2003). Groundwater pollution is a crucial environmental issue in this area, where a volcanic ignimbrite succession up to 500 m thick outcrops, locally covered by sand deposits of variable thickness. Groundwater upgradient to the industrial district shows sulphate concentrations exceeding the background value of 450 mg/L calculated for the area (Vecchio et al., 2011). In order to verify the origin of sulphate, multidisciplinary investigations were carried out on the geochemical features and stable isotope ratios in groundwater

Microfluidic platform for 3D cell culture with live imaging and clone retrieval.

Combining live imaging with the ability to retrieve individual cells of interest remains a technical challenge. Combining imaging with precise cell retrieval is of particular interest when studying highly dynamic or transient, asynchronous, or heterogeneous cell biological and developmental processes. Here, we present a method to encapsulate live cells in a 3D hydrogel matrix, via hydrogel bead compartmentalisation. Using a small-scale screen, we optimised matrix conditions for the culture and multilineage differentiation of mouse embryonic stem cells. Moreover, we designed a custom microfluidic platform that is compatible with live imaging. With this platform we can long-term culture and subsequently extract individual cells-in-beads by media flow only, obviating the need for enzymatic cell removal from the platform. Specific beads may be extracted from the platform in isolation, without disrupting the adjacent beads. We show that we can differentiate mouse embryonic stem cells, monitor reporter expression by live imaging, and retrieve individual beads for functional assays, correlating reporter expression with functional response. Overall, we present a highly flexible 3D cell encapsulation and microfluidic platform that enables both monitoring of cellular dynamics and retrieval for molecular and functional assays

Application of Phage Therapy in a Case of a Chronic Hip-Prosthetic Joint Infection due to Pseudomonas aeruginosa: An Italian Real-Life Experience and In Vitro Analysis

Background: Prosthetic joint infection (PJI) caused by Pseudomonas aeruginosa represents a severe complication in orthopedic surgery. We report the case of a patient with chronic PJI from P. aeruginosa successfully treated with personalized phage therapy (PT) in combination with meropenem. Methods: A 62-year-old woman was affected by a chronic right hip prosthesis infection caused by P. aeruginosa since 2016 . The patient was treated with phage Pa53 (I day 10 mL q8h, then 5 mL q8h via joint drainage for 2 weeks) in association with meropenem (2gr q12h iv) after a surgical procedure. A 2-year clinical follow up was performed. An in vitro bactericidal assay of the phage alone and in combination with meropenem against a 24-hour-old biofilm of bacterial isolate was also carried out. Results: No severe adverse events were observed during PT. Two years after suspension, there were no clinical signs of infection relapse, and a marked leukocyte scan showed no pathological uptake areas. In vitro studies showed that the minimum biofilm eradicating concentration of meropenem was 8 µg/mL. No biofilm eradication was observed at 24 hours incubation with phages alone (108 plaque-forming units [PFU]/mL). However, the addition of meropenem at suberadicating concentration (1 µg/mL) to phages at lower titer (103 PFU/mL) resulted in a synergistic eradication after 24 hours of incubation. Conclusions: Personalized PT, in combination with meropenem, was found to be safe and effective in eradicating P. aeruginosa infection. These data encourage the development of personalized clinical studies aimed at evaluating the efficacy of PT as an adjunct to antibiotic therapy for chronic persistent infections

The association between Major Depressive Disorder and premature death risk in hematologic and solid cancer: a longitudinal cohort study

Background: the aim was to verify the association between Major Depressive Disorders (MDD) and the risk of premature death in people with oncological diseases, and to collect evidence about the causality of a possible association from a longitudinal perspective.Design and Methods: it is a cohort study lasting 9 months, involving people with solid or hematologic cancers. The assessment was conducted by an ad hoc form to collect socio-demographic and clinical-oncological data, the PHQ-9 to screen MDD (cut-off ≥10) and the SF-12 to evaluate HRQoL. Relative Risk (RR) of early death between MDD exposed and not-exposed and Kaplan-Meier survival were carried out.Results: people exposed to MDD during the follow-up were 107/263 (40.7%). Among them, 36 deceased during the observation period. Overtime, having MDD and death’ occurrence showed a strong association (RR=2.15; 95% CI (1.10-4.20); χ²=5.224, p=0.0022), confirmed by Kaplan-Meier survival analysis (χ²=4.357, p=0.037). Among people who died, there was not any association between MDD, age, gender, HRQoL, cancer stage and site.Conclusions: the study confirms the association between MDD and early death in people with cancer. The absence of any association between the onset of MDD and advanced stage of cancer may suggest that it could be due to the consequences of MDD in worsening the clinical conditions related to cancer. The findings point out the relevance of MDD’ early detention among people with cancer

StemBond hydrogels control the mechanical microenvironment for pluripotent stem cells.

Studies of mechanical signalling are typically performed by comparing cells cultured on soft and stiff hydrogel-based substrates. However, it is challenging to independently and robustly control both substrate stiffness and extracellular matrix tethering to substrates, making matrix tethering a potentially confounding variable in mechanical signalling investigations. Moreover, unstable matrix tethering can lead to poor cell attachment and weak engagement of cell adhesions. To address this, we developed StemBond hydrogels, a hydrogel in which matrix tethering is robust and can be varied independently of stiffness. We validate StemBond hydrogels by showing that they provide an optimal system for culturing mouse and human pluripotent stem cells. We further show how soft StemBond hydrogels modulate stem cell function, partly through stiffness-sensitive ERK signalling. Our findings underline how substrate mechanics impact mechanosensitive signalling pathways regulating self-renewal and differentiation, indicating that optimising the complete mechanical microenvironment will offer greater control over stem cell fate specification

Long-Term Perfusion Culture of Monoclonal Embryonic Stem Cells in 3D Hydrogel Beads for Continuous Optical Analysis of Differentiation.

Developmental cell biology requires technologies in which the fate of single cells is followed over extended time periods, to monitor and understand the processes of self-renewal, differentiation, and reprogramming. A workflow is presented, in which single cells are encapsulated into droplets (Ø: 80 µm, volume: ≈270 pL) and the droplet compartment is later converted to a hydrogel bead. After on-chip de-emulsification by electrocoalescence, these 3D scaffolds are subsequently arrayed on a chip for long-term perfusion culture to facilitate continuous cell imaging over 68 h. Here, the response of murine embryonic stem cells to different growth media, 2i and N2B27, is studied, showing that the exit from pluripotency can be monitored by fluorescence time-lapse microscopy, by immunostaining and by reverse-transcription and quantitative PCR (RT-qPCR). The defined 3D environment emulates the natural context of cell growth (e.g., in tissue) and enables the study of cell development in various matrices. The large scale of cell cultivation (in 2000 beads in parallel) may reveal infrequent events that remain undetected in lower throughput or ensemble studies. This platform will help to gain qualitative and quantitative mechanistic insight into the role of external factors on cell behavior.Wellcome Trust WT108438/C/15/

Tracking the embryonic stem cell transition from ground state pluripotency

Mouse embryonic stem (ES) cells are locked into self-renewal by shielding from inductive cues. Release from this ground state in minimal conditions offers a system for delineating developmental progression from naive pluripotency. Here we examined the initial transition process. The ES cell population behaves asynchronously. We therefore exploited a short-half-life $\textit{Rex1::GFP}$ reporter to isolate cells either side of exit from naive status. Extinction of ES cell identity in single cells is acute. It occurs only after near-complete elimination of naïve pluripotency factors, but precedes appearance of lineage specification markers. Cells newly departed from the ES cell state display features of early post-implantation epiblast and are distinct from primed epiblast. They also exhibit a genome-wide increase in DNA methylation, intermediate between early and late epiblast. These findings are consistent with the proposition that naive cells transition to a distinct formative phase of pluripotency preparatory to lineage priming.This research was funded by the Wellcome Trust (091484/Z/10/Z and 095645/Z/11/Z), the Biotechnology and Biological Sciences Research Council (BB/M004023/1 and BB/K010867/1), a European Commission Framework 7 project EuroSyStem (HEALTH-F4-2007-200720 EUROSYSTEM), SysStemCell (ERC-2013-AdG 339431), the Medical Research Council (MRC) (G1100526/1) the Louis-Jeantet Foundation and the Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO-VIDI 864.12.007). The Cambridge Stem Cell Institute receives core funding from the Wellcome Trust and Medical Research Council (MRC). A.S. is an MRC Professor. Deposited in PMC for immediate release