Golgi Membranes Are Absorbed into and Reemerge from the ER during Mitosis

AbstractQuantitative imaging and photobleaching were used to measure ER/Golgi recycling of GFP-tagged Golgi proteins in interphase cells and to monitor the dissolution and reformation of the Golgi during mitosis. In interphase, recycling occurred every 1.5 hr, and blocking ER egress trapped cycling Golgi enzymes in the ER with loss of Golgi structure. In mitosis, when ER export stops, Golgi proteins redistributed into the ER as shown by quantitative imaging in vivo and immuno-EM. Comparison of the mobilities of Golgi proteins and lipids ruled out the persistence of a separate mitotic Golgi vesicle population and supported the idea that all Golgi components are absorbed into the ER. Moreover, reassembly of the Golgi complex after mitosis failed to occur when ER export was blocked. These results demonstrate that in mitosis the Golgi disperses and reforms through the intermediary of the ER, exploiting constitutive recycling pathways. They thus define a novel paradigm for Golgi genesis and inheritance

What are emergency ambulance services doing to meet the needs of people who call frequently? A national survey of current practice in the United Kingdom

Background Emergency ambulance services are integral to providing a service for those with unplanned urgent and life-threatening health conditions. However, high use of the service by a small minority of patients is a concern. Our objectives were to describe: service-wide and local policies or pathways for people classified as Frequent Caller; call volume; and results of any audit or evaluation. Method We conducted a national survey of current practice in ambulance services in relation to the management of people who call the emergency ambulance service frequently using a structured questionnaire for completion by email and telephone interview. We analysed responses using a descriptive and thematic approach. Results Twelve of 13 UK ambulance services responded. Most services used nationally agreed definitions for ‘Frequent Caller’, with 600–900 people meeting this classification each month. Service-wide policies were in place, with local variations. Models of care varied from within-service care where calls are flagged in the call centre; contact made with callers; and their General Practitioner (GP) with an aim of discouraging further calls, to case management through cross-service, multi-disciplinary team meetings aiming to resolve callers’ needs. Although data were available related to volume of calls and number of callers meeting the threshold for definition as Frequent Caller, no formal audits or evaluations were reported. Conclusions Ambulance services are under pressure to meet challenging response times for high acuity patients. Tensions are apparent in the provision of care to patients who have complex needs and call frequently. Multi-disciplinary case management approaches may help to provide appropriate care, and reduce demand on emergency services. However, there is currently inadequate evidence to inform commissioning, policy or practice development

Sialidases Affect the Host Cell Adherence and Epsilon Toxin-Induced Cytotoxicity of Clostridium perfringens Type D Strain CN3718

Clostridium perfringens type B or D isolates, which cause enterotoxemias or enteritis in livestock, produce epsilon toxin (ETX). ETX is exceptionally potent, earning it a listing as a CDC class B select toxin. Most C. perfringens strains also express up to three different sialidases, although the possible contributions of those enzymes to type B or D pathogenesis remain unclear. Type D isolate CN3718 was found to carry two genes (nanI and nanJ) encoding secreted sialidases and one gene (nanH) encoding a cytoplasmic sialidase. Construction in CN3718 of single nanI, nanJ and nanH null mutants, as well as a nanI/nanJ double null mutant and a triple sialidase null mutant, identified NanI as the major secreted sialidase of this strain. Pretreating MDCK cells with NanI sialidase, or with culture supernatants of BMC206 (an isogenic CN3718 etx null mutant that still produces sialidases) enhanced the subsequent binding and cytotoxic effects of purified ETX. Complementation of BMC207 (an etx/nanH/nanI/nanJ null mutant) showed this effect is mainly attributable to NanI production. Contact between BMC206 and certain mammalian cells (e.g., enterocyte-like Caco-2 cells) resulted in more rapid sialidase production and this effect involved increased transcription of BMC206 nanI gene. BMC206 was shown to adhere to some (e.g. Caco-2 cells), but not all mammalian cells, and this effect was dependent upon sialidase, particularly NanI, expression. Finally, the sialidase activity of NanI (but not NanJ or NanH) could be enhanced by trypsin. Collectively these in vitro findings suggest that, during type D disease originating in the intestines, trypsin may activate NanI, which (in turn) could contribute to intestinal colonization by C. perfringens type D isolates and also increase ETX action

Clinical experience in T cell deficient patients

T cell disorders have been poorly understood until recently. Lack of knowledge of underlying molecular mechanisms together with incomplete data on long term outcome have made it difficult to assess prognosis and give the most effective treatment. Rapid progress in defining molecular defects, improved supportive care and much improved results from hematopoietic stem cell transplantation (HSCT) now mean that curative treatment is possible for many patients. However, this depends on prompt recognition, accurate diagnosis and careful treatment planning

High-coverage genomes to elucidate the evolution of penguins

Background: Penguins (Sphenisciformes) are a remarkable order of flightless wing-propelled diving seabirds distributed widely across the southern hemisphere. They share a volant common ancestor with Procellariiformes close to the Cretaceous-Paleogene boundary (66 million years ago) and subsequently lost the ability to fly but enhanced their diving capabilities. With ∼20 species among 6 genera, penguins range from the tropical Galápagos Islands to the oceanic temperate forests of New Zealand, the rocky coastlines of the sub-Antarctic islands, and the sea ice around Antarctica. To inhabit such diverse and extreme environments, penguins evolved many physiological and morphological adaptations. However, they are also highly sensitive to climate change. Therefore, penguins provide an exciting target system for understanding the evolutionary processes of speciation, adaptation, and demography. Genomic data are an emerging resource for addressing questions about such processes. Results: Here we present a novel dataset of 19 high-coverage genomes that, together with 2 previously published genomes, encompass all extant penguin species. We also present a well-supported phylogeny to clarify the relationships among penguins. In contrast to recent studies, our results demonstrate that the genus Aptenodytes is basal and sister to all other extant penguin genera, providing intriguing new insights into the adaptation of penguins to Antarctica. As such, our dataset provides a novel resource for understanding the evolutionary history of penguins as a clade, as well as the fine-scale relationships of individual penguin lineages. Against this background, we introduce a major consortium of international scientists dedicated to studying these genomes. Moreover, we highlight emerging issues regarding ensuring legal and respectful indigenous consultation, particularly for genomic data originating from New Zealand Taonga species. Conclusions: We believe that our dataset and project will be important for understanding evolution, increasing cultural heritage and guiding the conservation of this iconic southern hemisphere species assemblage.Fil: Pan, Hailin. Bgi-shenzhen; ChinaFil: Cole, Theresa L. University Of Otago; CanadáFil: Bi, Xupeng. Bgi-shenzhen; ChinaFil: Fang, Miaoquan. Bgi-shenzhen; ChinaFil: Zhou, Chengran. Bgi-shenzhen; ChinaFil: Yang, Zhengtao. Bgi-shenzhen; ChinaFil: Ksepka, Daniel T. Bruce Museum; Estados UnidosFil: Hart, Tom. University of Oxford; Reino UnidoFil: Bouzat, Juan L.. Bowling Green State University; Estados UnidosFil: Boersma, P. Dee. University of Washington; Estados UnidosFil: Bost, Charles-André. Centre Detudes Biologiques de Chizé; FranciaFil: Cherel, Yves. Centre Detudes Biologiques de Chizé; FranciaFil: Dann, Peter. Phillip Island Nature Parks; AustraliaFil: Mattern, Thomas. University of Otago; Nueva ZelandaFil: Ellenberg, Ursula. Global Penguin Society; Estados Unidos. La Trobe University; AustraliaFil: Garcia Borboroglu, Jorge Pablo. University of Washington; Estados Unidos. Global Penguin Society; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; ArgentinaFil: Argilla, Lisa S.. Otago Polytechnic; Nueva ZelandaFil: Bertelsen, Mads F.. Copenhagen Zoo; Dinamarca. University of Copenhagen; DinamarcaFil: Fiddaman, Steven R.. University of Oxford; Reino UnidoFil: Howard, Pauline. Hornby Veterinary Centre; Nueva Zelanda. South Island Wildlife Hospital; Nueva ZelandaFil: Labuschagne, Kim. National Zoological Garden; SudáfricaFil: Miller, Gary. University of Western Australia; Australia. University of Tasmania; AustraliaFil: Parker, Patricia. University of Missouri St. Louis; Estados UnidosFil: Phillips, Richard A.. Natural Environment Research Council; Reino UnidoFil: Quillfeldt, Petra. Justus-Liebig-Universit ̈ at Giessen; AlemaniaFil: Ryan, Peter G.. University of Cape Town; SudáfricaFil: Taylor, Helen. Vet Services Hawkes Bay Ltd; Nueva Zelanda. Wairoa Farm Vets; Nueva ZelandaFil: Zhang, De-Xing. Chinese Academy of Sciences; República de ChinaFil: Zhang, Guojie. BGI-Shenzhen; China. Chinese Academy of Sciences; República de China. University of Copenhagen; DinamarcaFil: McKinlay, Bruce. Department of Conservation; Nueva Zeland

Activating PIK3CD mutations impair human cytotoxic lymphocyte differentiation and function and EBV immunity

Background Germline gain-of function (GOF) mutations in PIK3CD, encoding the catalytic p110δ subunit of phosphoinositide 3-kinase (PI3K), result in hyperactivation of the PI3K–AKT–mechanistic target of rapamycin pathway and underlie a novel inborn error of immunity. Affected subjects exhibit perturbed humoral and cellular immunity, manifesting as recurrent infections, autoimmunity, hepatosplenomegaly, uncontrolled EBV and/or cytomegalovirus infection, and increased incidence of B-cell lymphoproliferation, lymphoma, or both. Mechanisms underlying disease pathogenesis remain unknown. Objective Understanding the cellular and molecular mechanisms underpinning inefficient surveillance of EBV-infected B cells is required to understand disease in patients with PIK3CD GOF mutations, identify key molecules required for cell-mediated immunity against EBV, and develop immunotherapeutic interventions for the treatment of this and other EBV-opathies. Methods We studied the consequences of PIK3CD GOF mutations on the generation, differentiation, and function of CD8+ T cells and natural killer (NK) cells, which are implicated in host defense against infection with herpesviruses, including EBV. Results PIK3CD GOF total and EBV-specific CD8+ T cells were skewed toward an effector phenotype, with exaggerated expression of markers associated with premature immunosenescence/exhaustion and increased susceptibility to reactivation-induced cell death. These findings were recapitulated in a novel mouse model of PI3K GOF mutations. NK cells in patients with PIK3CD GOF mutations also exhibited perturbed expression of differentiation-associated molecules. Both CD8+ T and NK cells had reduced capacity to kill EBV-infected B cells. PIK3CD GOF B cells had increased expression of CD48, programmed death ligand 1/2, and CD70. Conclusions PIK3CD GOF mutations aberrantly induce exhaustion, senescence, or both and impair cytotoxicity of CD8+ T and NK cells. These defects might contribute to clinical features of affected subjects, such as impaired immunity to herpesviruses and tumor surveillance

Peripheral CD103+ dendritic cells form a unified subset developmentally related to CD8α+ conventional dendritic cells

Although CD103-expressing dendritic cells (DCs) are widely present in nonlymphoid tissues, the transcription factors controlling their development and their relationship to other DC subsets remain unclear. Mice lacking the transcription factor Batf3 have a defect in the development of CD8α(+) conventional DCs (cDCs) within lymphoid tissues. We demonstrate that Batf3(−/−) mice also lack CD103(+)CD11b(−) DCs in the lung, intestine, mesenteric lymph nodes (MLNs), dermis, and skin-draining lymph nodes. Notably, Batf3(−/−) mice displayed reduced priming of CD8 T cells after pulmonary Sendai virus infection, with increased pulmonary inflammation. In the MLNs and intestine, Batf3 deficiency resulted in the specific lack of CD103(+)CD11b(−) DCs, with the population of CD103(+)CD11b(+) DCs remaining intact. Batf3(−/−) mice showed no evidence of spontaneous gastrointestinal inflammation and had a normal contact hypersensitivity (CHS) response, despite previous suggestions that CD103(+) DCs were required for immune homeostasis in the gut and CHS. The relationship between CD8α(+) cDCs and nonlymphoid CD103(+) DCs implied by their shared dependence on Batf3 was further supported by similar patterns of gene expression and their shared developmental dependence on the transcription factor Irf8. These data provide evidence for a developmental relationship between lymphoid organ–resident CD8α(+) cDCs and nonlymphoid CD103(+) DCs

Interferon-Inducible CXC Chemokines Directly Contribute to Host Defense against Inhalational Anthrax in a Murine Model of Infection

Chemokines have been found to exert direct, defensin-like antimicrobial activity in vitro, suggesting that, in addition to orchestrating cellular accumulation and activation, chemokines may contribute directly to the innate host response against infection. No observations have been made, however, demonstrating direct chemokine-mediated promotion of host defense in vivo. Here, we show that the murine interferon-inducible CXC chemokines CXCL9, CXCL10, and CXCL11 each exert direct antimicrobial effects in vitro against Bacillus anthracis Sterne strain spores and bacilli including disruptions in spore germination and marked reductions in spore and bacilli viability as assessed using CFU determination and a fluorometric assay of metabolic activity. Similar chemokine-mediated antimicrobial activity was also observed against fully virulent Ames strain spores and encapsulated bacilli. Moreover, antibody-mediated neutralization of these CXC chemokines in vivo was found to significantly increase host susceptibility to pulmonary B. anthracis infection in a murine model of inhalational anthrax with disease progression characterized by systemic bacterial dissemination, toxemia, and host death. Neutralization of the shared chemokine receptor CXCR3, responsible for mediating cellular recruitment in response to CXCL9, CXCL10, and CXCL11, was not found to increase host susceptibility to inhalational anthrax. Taken together, our data demonstrate a novel, receptor-independent antimicrobial role for the interferon-inducible CXC chemokines in pulmonary innate immunity in vivo. These data also support an immunomodulatory approach for effectively treating and/or preventing pulmonary B. anthracis infection, as well as infections caused by pathogenic and potentially, multi-drug resistant bacteria including other spore-forming organisms

Hyperoxemia and excess oxygen use in early acute respiratory distress syndrome : Insights from the LUNG SAFE study

Publisher Copyright: © 2020 The Author(s). Copyright: Copyright 2020 Elsevier B.V., All rights reserved.Background: Concerns exist regarding the prevalence and impact of unnecessary oxygen use in patients with acute respiratory distress syndrome (ARDS). We examined this issue in patients with ARDS enrolled in the Large observational study to UNderstand the Global impact of Severe Acute respiratory FailurE (LUNG SAFE) study. Methods: In this secondary analysis of the LUNG SAFE study, we wished to determine the prevalence and the outcomes associated with hyperoxemia on day 1, sustained hyperoxemia, and excessive oxygen use in patients with early ARDS. Patients who fulfilled criteria of ARDS on day 1 and day 2 of acute hypoxemic respiratory failure were categorized based on the presence of hyperoxemia (PaO2 > 100 mmHg) on day 1, sustained (i.e., present on day 1 and day 2) hyperoxemia, or excessive oxygen use (FIO2 ≥ 0.60 during hyperoxemia). Results: Of 2005 patients that met the inclusion criteria, 131 (6.5%) were hypoxemic (PaO2 < 55 mmHg), 607 (30%) had hyperoxemia on day 1, and 250 (12%) had sustained hyperoxemia. Excess FIO2 use occurred in 400 (66%) out of 607 patients with hyperoxemia. Excess FIO2 use decreased from day 1 to day 2 of ARDS, with most hyperoxemic patients on day 2 receiving relatively low FIO2. Multivariate analyses found no independent relationship between day 1 hyperoxemia, sustained hyperoxemia, or excess FIO2 use and adverse clinical outcomes. Mortality was 42% in patients with excess FIO2 use, compared to 39% in a propensity-matched sample of normoxemic (PaO2 55-100 mmHg) patients (P = 0.47). Conclusions: Hyperoxemia and excess oxygen use are both prevalent in early ARDS but are most often non-sustained. No relationship was found between hyperoxemia or excessive oxygen use and patient outcome in this cohort. Trial registration: LUNG-SAFE is registered with ClinicalTrials.gov, NCT02010073publishersversionPeer reviewe