Novel RNAseq-informed cell-type markers and their regulation alter paradigms of Dictyostelium developmental control

Cell differentiation is traditionally monitored with a few marker genes, which may bias results. To understand the evolution and regulation of the spore, stalk, cup and basal disc cells in Dictyostelia, we previously performed RNAseq on purified cell-types of taxon-group representative dictyostelids. Using promoter-lacZ constructs in D. discoideum, we here investigate the spatio-temporal expression pattern of 29 cell-type specific genes. Genes selected for spore- or cup-specificity in RNAseq were validated as such by lacZ expression, but genes selected for stalk-specificity showed variable additional expression in basal disc, early cup or prestalk populations. We measured responses of 25 genes to 15 single or combined regimes of induction by stimuli known to regulate cell differentiation. The outcomes of these experiments were subjected to hierarchical clustering to identify whether common modes of regulation were correlated with specific expression patterns. The analysis identified a cluster combining the spore and cup genes, which shared upregulation by 8-bromo cyclic AMP and down-regulation by Differentiation Inducing Factor 1 (DIF-1). Most stalk-expressed genes combined into a single cluster and shared strong upregulation by cyclic di-guanylate (c-di-GMP), and synergistic upregulation by combined DIF-1 and c-di-GMP. There was no clustering of genes expressed in other soma besides the stalk, but two genes that were only expressed in the stalk did not respond to any stimuli. In contrast to current models, the study indicates the existence of a stem-cell like soma population in slugs, whose members only acquire ultimate cell fate after progressing to their terminal location during fruiting body morphogenesis.This research was funded by ERC advanced grant 742288. Z-HC. was additionally funded by Wellcome grant 100293/Z/12/Z and K.K. was additionally supported by EMBO long-term fellowship ALTF 295–2015 and by JSPS Overseas Research Fellowship H28–1002.Peer reviewe

Loss of Pikfyve causes Transdifferentiation of Dictyostelium Spores into Basal Disc Cells

The 1-phosphatidylinositol-3-phosphate 5-kinase PIKfyve generates PtdIns3,5P2 on late phagolysosomes, which by recruiting the scission protein Atg18, results in their fragmentation in the normal course of endosome processing. Loss of PIKfyve function causes cellular hypervacuolization in eukaryotes and organ failure in humans. We identified pikfyve as the defective gene in a Dictyostelium mutant that failed to form spores. The amoebas normally differentiated into prespore cells and initiated spore coat protein synthesis in Golgi-derived prespore vesicles. However, instead of exocytosing, the prespore vesicles fused into the single vacuole that typifies the stalk and basal disc cells that support the spores. This process was accompanied by stalk wall biosynthesis, loss of spore gene expression and overexpression of ecmB, a basal disc and stalk-specific gene, but not of the stalk-specific genes DDB_G0278745 and DDB_G0277757. Transdifferentiation of prespore into stalk-like cells was previously observed in mutants that lack early autophagy genes, like atg5, atg7, and atg9. However, while autophagy mutants specifically lacked cAMP induction of prespore gene expression, pikfyve(−) showed normal early autophagy and prespore induction, but increased in vitro induction of ecmB. Combined, the data suggest that the Dictyostelium endosomal system influences cell fate by acting on cell type specific gene expression

Factors influencing staff attitudes to COVID-19 vaccination in care homes in England: a qualitative study

BACKGROUND: The COVID-19 pandemic disproportionately affected people living and working in UK care homes causing high mortality rates. Vaccinating staff members and residents is considered the most effective intervention to reduce infection and its transmission rates. However, uptake of the first dose of the COVID-19 vaccine in care homes was variable. We sought to investigate factors influencing uptake of COVID-19 vaccination in care home staff to inform strategies to increase vaccination uptake and inform future preparedness. METHODS: Twenty care home staff including managerial and administrative staff, nurses, healthcare practitioners and support staff from nine care homes across England participated in semi-structured telephone interviews (March-June 2021) exploring attitudes towards the COVID-19 vaccine and factors influencing uptake. We used thematic analysis to generate themes which were subsequently deductively mapped to the Capability, Opportunity, Motivation-Behaviour (COM-B) model. The Behavioural Change Wheel (BCW) was used to identify potential intervention strategies to address identified influences. RESULTS: Enablers to vaccine uptake included the willingness to protect care home residents, staff and family/friends from infection and the belief that vaccination provided a way back to normality (reflective motivation); convenience of vaccination and access to accurate information (physical opportunity); and a supporting social environment around them favouring vaccination (social opportunity). Barriers included fears about side-effects (automatic motivation); a lack of trust due to the quick release of the vaccine (reflective motivation); and feeling pressurised to accept vaccination if mandatory (automatic motivation). CONCLUSIONS: We identified influences on COVID-19 vaccine uptake by care home staff that can inform the implementation of future vaccination programmes. Strategies likely to support uptake include information campaigns and facilitating communication between staff and managers to openly discuss concerns regarding possible vaccination side effects. Freedom of choice played an important role in the decision to be vaccinated suggesting that the decision to mandate vaccination may have unintended behavioural consequences

Factors influencing staff attitudes to COVID-19 vaccination in care homes in England:a qualitative study

Background: The COVID-19 pandemic disproportionately affected people living and working in UK care homes causing high mortality rates. Vaccinating staff members and residents is considered the most effective intervention to reduce infection and its transmission rates. However, uptake of the first dose of the COVID-19 vaccine in care homes was variable. We sought to investigate factors influencing uptake of COVID-19 vaccination in care home staff to inform strategies to increase vaccination uptake and inform future preparedness. Methods: Twenty care home staff including managerial and administrative staff, nurses, healthcare practitioners and support staff from nine care homes across England participated in semi-structured telephone interviews (March-June 2021) exploring attitudes towards the COVID-19 vaccine and factors influencing uptake. We used thematic analysis to generate themes which were subsequently deductively mapped to the Capability, Opportunity, Motivation-Behaviour (COM-B) model. The Behavioural Change Wheel (BCW) was used to identify potential intervention strategies to address identified influences. Results: Enablers to vaccine uptake included the willingness to protect care home residents, staff and family/friends from infection and the belief that vaccination provided a way back to normality (reflective motivation); convenience of vaccination and access to accurate information (physical opportunity); and a supporting social environment around them favouring vaccination (social opportunity). Barriers included fears about side-effects (automatic motivation); a lack of trust due to the quick release of the vaccine (reflective motivation); and feeling pressurised to accept vaccination if mandatory (automatic motivation). Conclusions: We identified influences on COVID-19 vaccine uptake by care home staff that can inform the implementation of future vaccination programmes. Strategies likely to support uptake include information campaigns and facilitating communication between staff and managers to openly discuss concerns regarding possible vaccination side effects. Freedom of choice played an important role in the decision to be vaccinated suggesting that the decision to mandate vaccination may have unintended behavioural consequences.</p

Exploration of the individual, social and environmental factors influencing dietary behaviour in shift workers with type 2 diabetes working in UK healthcare—The Shift-Diabetes Study:A qualitative study using the theoretical domains framework

Aim: To identify factors influencing dietary behaviour in shift workers with type 2 diabetes (T2D) working in UK healthcare settings. Methods: Semi-structured qualitative interviews based on the theoretical domains framework (TDF) were conducted with a convenience sample (n = 15) of shift workers (32–59 years) diagnosed with T2D who worked night shifts as part of a mixed shift schedule. The TDF was applied to analyse transcripts using a combined deductive framework and inductive thematic analysis approach. Identified influences were mapped to the behaviour change technique taxonomy to identify potential strategies to change dietary behaviour in this context. Results: Key barriers to healthy dietary behaviours were access and cost of food available during night work (TDF domain: Environment Context and Resources). Factors identified as both enablers and barriers included: availability of staff facilities and time to take a break, (Environment Context and Resources), the physical impact of night work (Beliefs About Consequences), eating in response to stress or tiredness (Emotion), advance planning of meals/food and taking own food to work (Behavioural Regulation). Potential techniques to address these influences and improve dietary behaviour in this context include: meal planning templates, self-monitoring and biofeedback, and increasing accessibility and availability of healthier food choices during night shifts. Conclusions: The dietary behaviour of shift workers with T2D is influenced by interacting individual, socio-cultural and environmental factors. Intervention should focus on environmental restructuring and strategies that enable monitoring and meal planning.</p

Exploration of the individual, social and environmental factors influencing dietary behaviour in shift workers with type 2 diabetes working in UK healthcare - the Shift-Diabetes Study: a qualitative study using the Theoretical Domains Framework

AIM: To identify factors influencing dietary behaviour in shift workers with type 2 diabetes (T2D) working in UK healthcare settings. METHODS: Semi-structured qualitative interviews based on the Theoretical Domains Framework (TDF) were conducted with a convenience sample (n=15) of shift-workers (32 - 59 years) diagnosed with T2D who worked night shifts as part of a mixed shift schedule. The TDF was applied to analyse transcripts using a combined deductive framework and inductive thematic analysis approach. Identified influences were mapped to the behaviour change technique taxonomy to identify potential strategies to change dietary behaviour in this context. RESULTS: Key barriers to healthy dietary behaviours were access and cost of food available during night work (TDF domain: Environment Context and Resources). Factors identified as both enablers and barriers included: availability of staff facilities and time to take a break, (Environment Context and Resources), the physical impact of night work (Beliefs About Consequences), eating in response to stress or tiredness (Emotion), advance planning of meals/food and taking own food to work (Behavioural Regulation). Potential techniques to address these influences and improve dietary behaviour in this context include: meal planning templates, self-monitoring, and biofeedback, and increasing accessibility and availability of healthier food choices during night shifts. CONCLUSIONS: The dietary behaviour of shift workers with T2D is influenced by interacting individual, socio-cultural and environmental factors. Intervention should focus on environmental restructuring and strategies that enable monitoring and meal planning

Interactome and evolutionary conservation of Dictyostelid small GTPases and their direct regulators

The GTP binding proteins known as small GTPases make up one of the largest groups of regulatory proteins and control almost all functions of living cells. Their activity is under respectively positive and negative regulation by guanine nucleotide exchange factors (GEFs) and GTPase activating proteins (GAPs), which together with their upstream regulators and the downstream targets of the small GTPases form formidable signaling networks. While genomics has revealed the large size of the GTPase, GEF and GAP repertoire, only a small fraction of their interactions and functions have yet been experimentally explored. Dictyostelid social amoebas have been particularly useful in unraveling the roles of many proteins in the Rac-Rho and Ras-Rap families of GTPases in directional cell migration and regulation of the actin cytoskeleton. Almost completely assembled genomes and cell-type specific and developmental transcriptomes are available for Dictyostelium species that span the 0.5 billion years of evolution of the group from their unicellular ancestor. In this work, we identified all GTPases, GEFs and GAP from genomes representative of the four major taxon groups and investigated their phylogenetic relationships and evolutionary conservation and change in their functional domain architecture and in their developmental and cell-type specific expression. We performed hierarchical cluster analysis of the expression profiles of the ~2000 analysed genes to identify putative interacting sets of GTPases, GEFs and GAPs, which highlighted sets known to interact experimentally and many novel combinations. The work represents a valuable resource for research into all fields of cellular regulation

Systematic review and network meta-analysis on the efficacy of evolocumab and other therapies for the management of lipid levels in hyperlipidemia

Background: The proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors evolocumab and alirocumab substantially reduce low‐density lipoprotein cholesterol (LDL‐C) when added to statin therapy in patients who need additional LDL‐C reduction. Methods and Results: We conducted a systematic review and network meta‐analysis of randomized trials of lipid‐lowering therapies from database inception through August 2016 (45 058 records retrieved). We found 69 trials of lipid‐lowering therapies that enrolled patients requiring further LDL‐C reduction while on maximally tolerated medium‐ or high‐intensity statin, of which 15 could be relevant for inclusion in LDL‐C reduction networks with evolocumab, alirocumab, ezetimibe, and placebo as treatment arms. PCSK9 inhibitors significantly reduced LDL‐C by 54% to 74% versus placebo and 26% to 46% versus ezetimibe. There were significant treatment differences for evolocumab 140 mg every 2 weeks at the mean of weeks 10 and 12 versus placebo (−74.1%; 95% credible interval −79.81% to −68.58%), alirocumab 75 mg (−20.03%; 95% credible interval −27.32% to −12.96%), and alirocumab 150 mg (−13.63%; 95% credible interval −22.43% to −5.33%) at ≥12 weeks. Treatment differences were similar in direction and magnitude for PCSK9 inhibitor monthly dosing. Adverse events were similar between PCSK9 inhibitors and control. Rates of adverse events were similar between PCSK9 inhibitors versus placebo or ezetimibe. Conclusions: PCSK9 inhibitors added to medium‐ to high‐intensity statin therapy significantly reduce LDL‐C in patients requiring further LDL‐C reduction. The network meta‐analysis showed a significant treatment difference in LDL‐C reduction for evolocumab versus alirocumab