Functional and Crystal Structure Analysis of Active Site Adaptations of a Potent Anti-Angiogenic Human tRNA Synthetase

SummaryHigher eukaryote tRNA synthetases have expanded functions that come from enlarged, more differentiated structures that were adapted to fit aminoacylation function. How those adaptations affect catalytic mechanisms is not known. Presented here is the structure of a catalytically active natural splice variant of human tryptophanyl-tRNA synthetase (TrpRS) that is a potent angiostatic factor. This and related structures suggest that a eukaryote-specific N-terminal extension of the core enzyme changed substrate recognition by forming an active site cap. At the junction of the extension and core catalytic unit, an arginine is recruited to replace a missing landmark lysine almost 200 residues away. Mutagenesis, rapid kinetic, and substrate binding studies support the functional significance of the cap and arginine recruitment. Thus, the enzyme function of human TrpRS has switched more to the N terminus of the sequence. This switch has the effect of creating selective pressure to retain the N-terminal extension for functional expansion

Structural insights into the extracellular recognition of the human serotonin 2B receptor by an antibody

Highly selective monoclonal antibodies recognizing the extracellular 3D epitope of G protein-coupled receptors represent valuable tools for elucidating receptor function and localization in the cell and show promise for a range of therapeutic applications. Here we present the structure of a complex between the human serotonin 2B receptor, captured in an active-like state, and an antibody Fab fragment, bound to the extracellular side of the receptor. The structure uncovers the mechanisms of receptor activation and of extracellular receptor recognition by antibodies

Marked T cell activation, senescence, exhaustion and skewing towards TH17 in patients with Covid-19 pneumonia.

We provide an in-depth investigation of the T cell compartment and functionality, cytokine production and plasma levels in a total of 39 patients affected by Covid-19 pneumonia. At admission, patients were lymphopenic; for all, SARS-CoV-2 was detected in a nasopharyngeal swab specimen by real-time RT-PCR, and pneumonia was subsequently confirmed by X-rays. Detailed 18-parameter flow cytometry coupled with unsupervised data analysis revealed that patients showed similar percentages of CD4+ and CD8+ T cells, but a decreased absolute number in both populations. For CD4+ T lymphocytes, we found a significant decrease in the number of na\uefve, central and effector memory cells and an increased percentage of terminally differentiated cells, regulatory T cells, and of those that were activated or that were expressing PD1 and CD57 markers. Studies on chemokine receptors and lineage-specifying transcription factors revealed that, among CD4+ T cells, patients displayed a lower percentage of cells expressing CCR6 or CXCR3, and of those co-expressing CCR6 and CD161, but higher percentages of 62 CXCR4+ or CCR4+ cells. No differences were noted in the expression of T-bet or GATA-3. Analyses of patients' CD8+ T cells showed decreased numbers of na\uefve and central memory and increased amounts of activated cells, accompanied by increased percentages of activated cells and of lymphocytes expressing CD57, PD1, or both. CD8+ T cells expressed lower percentages of CCR6+, CXCR3+ or T-bet+ cells and of CXCR3+,T-bet+ or CCR6+,CD161+ lymphocytes. We also found higher percentages of cells expressing CCR4+, CXCR4 or GATA-3. Analyses of lymphocyte proliferation revealed that terminally differentiated CD4+ and CD8+ T cell from patients had a lower proliferative index than controls, whereas cellular bioenergetics, measured by the quantification of mitochondrial oxygen consumption and extracellular acidification rate, was similar in CD4+ T cells from both groups. We measured plasma level of 31 cytokines linked to inflammation, including T helper (TH)type-1 and TH2 cytokines, chemokines, galectins, pro- and anti-inflammatory mediators, finding that most were dramatically increased in Covid-19 patients, confirming the presence of a massive cytokine storm. Analysis of the production of different cytokines after stimulation by anti-CD3/CD28 monoclonal antibodies revealed that patients not only had a high capacity to produce tumour necrosis factor (TNF)-\u3b1, interferon (IFN)-\u3b3 and interleukin (IL)-2, but also showed a significant skewing of CD4+ T cells towards the TH17 phenotype. A therapeutic approach now exists based on the administration of drugs that block IL-6pathway, and seems to improve the disease. IL-17 is crucial in recruiting and activating neutrophils, cells that can migrate to the lung and are heavily involved in the pathogenesis of Covid-19. We show here that a skewing of activated T cells towards the TH17 functional phenotype exists in Covid-19 patients. We therefore suggest that blocking the IL-17 pathway by biological drugs that are already used to treat different pathologies could provide a novel, additional strategy to improve the health of patients infected by SARS-CoV-2

Mapping cropland in Ethiopia using crowdsourcing

The spatial distribution of cropland is an important input to many applications including food security monitoring and economic land use modeling. Global land cover maps derived from remote sensing are one source of cropland but they are currently not accurate enough in the cropland domain to meet the needs of the user community. Moreover, when compared with one another, these land cover products show large areas of spatial disagreement, which makes the choice very difficult regarding which land cover product to use. This paper takes an entirely different approach to mapping cropland, using crowdsourcing of Google Earth imagery via tools in Geo-Wiki. Using sample data generated by a crowdsourcing campaign for the collection of the degree of cultivation and settlement in Ethiopia, a cropland map was created using simple inverse distance weighted interpolation. The map was validated using data from the GOFC-GOLD validation portal and an independent crowdsourced dataset from Geo-Wiki. The results show that the crowdsourced cropland map for Ethiopia has a higher overall accuracy than the individual global land cover products for this country. Such an approach has great potential for mapping cropland in other countries where such data do not currently exist. Not only is the approach inexpensive but the data can be collected over a very short period of time using an existing network of volunteers

Power system dynamic state estimation: motivations, definitions, methodologies, and future work

This paper summarizes the technical activities of the Task Force on Power System Dynamic State and Parameter Estimation. This Task Force was established by the IEEE Working Group on State Estimation Algorithms to investigate the added benefits of dynamic state and parameter estimation for the enhancement of the reliability, security, and resilience of electric power systems. The motivations and engineering values of dynamic state estimation (DSE) are discussed in detail. Then, a set of potential applications that will rely on DSE is presented and discussed. Furthermore, a unified framework is proposed to clarify the important concepts related to DSE, forecasting-aided state estimation, tracking state estimation, and static state estimation. An overview of the current progress in DSE and dynamic parameter estimation is provided. The paper also provides future research needs and directions for the power engineering community

Simulation for training in sinus floor elevation : new surgical bench model

Objectives: to describe a bench model (workshop of abilities) for sinus floor elevation (SFE) training that simulates the surgical environment and to assess its effectiveness in terms of trainees? perception. Study design: thirty-six randomly selected postgraduate students entered this cross-sectional pilot study and asked to fill in an anonymous, self-applied, 12-item questionnaire about a SFE workshop that included a study guide containing the workshop?s details, supervised practice on a simulated surgical environment, and assessment by means of specific check-lists. Results: Thirtiy-six fresh sheep heads were prepared to allow access to the buccal vestible. Using the facial tuber, third premolar and a 3D-CT study as landmarks for trepanation, the sinus membrane was lifted, the space filled with ceramic material and closed with a resorbable membrane. The participants agreed on their ability to perform SFE in a simulated situation (median score= 4.5; range 2-5) and felt capable to teach the technique to other clinicians or to undertake the procedure for a patient under supervision of an expert surgeon (median= 4; range 1-5 ). There were no differences on their perceived ability to undertake the technique on a model or on a real patient under supervision of an expert surgeon (p=0.36). Conclusions: Clinical abilities workshops for SFE teaching are an essential educational tool but supervised clinical practice should always precede autonomous SFE on real patients. Simulation procedures (workshop of abilities) are perceived by the partakers as useful for the surgical practice. However, more studies are needed to validate the procedure and to address cognitive and communication skills, that are clearly integral parts of surgical performance

Do parents of children with congenital malformations have a higher cancer risk? A nationwide study in Denmark

To investigate whether parents of children with congenital malformations more often developed cancer after birth of the child, a population-based case-control study in Denmark was undertaken. By linking the Cancer Registry with the Central Population Registry, we identified 8783 cancer patients having their first child born between 1977 and 1995 before the cancer was diagnosed. Parents of 41 206 firstborn children of a 10% random sample of newborns from the Birth Registry between 1980 and 1995 were identified as controls. We obtained malformation diagnoses of children of cases and controls by linking to the Hospital Discharge Registry. We estimated the association between malformation and cancer by using logistic regression, adjusting for maternal age at birth and sex of child. We found no increased risk of cancer in parents having children with malformations in general, but a higher cancer risk in parents of children born with cleft lip/palate, odds ratio (OR) for all cancer=1.8 (95% confidence interval 1.0–3.2), OR for lymphomas=4.2 (1.3–13.5) and OR for leukaemia=8.1 (2.0–33.7). This association was not restricted to cancer cases diagnosed shortly after birth of the child. Our results suggest a common genetic association between these diseases, but further studies are needed

Prevalence of congenital heart defects in neuroblastoma patients: a cohort study and systematic review of literature

Data on the prevalence of congenital heart defects (CHD) in neuroblastoma patients are inconsistent. If CHD are more common in neuroblastoma patients than in the general population, cardiac screening might be warranted. In this study we used echocardiography to determine the prevalence of CHD in a single centre cohort of surviving neuroblastoma patients. In addition, we performed a systematic review of the literature. Echocardiography was performed in 119 of 133 patients (89.5%). Only two patients (1.7%) had CHD. The prevalence of CHD was not significantly different from a previously published control group of 192 leukaemia patients examined by echocardiography (P = 0.49). Literature search revealed 17 studies, showing prevalence rates of CHD in neuroblastoma patients ranging from 0 to 20%. Prevalence was less than 3.6% in the majority of studies. Most studies lacked information on validity. We conclude that current evidence does not support standard cardiac screening in all patients with neuroblastoma