Persistent ER Stress Induces the Spliced Leader RNA Silencing Pathway (SLS), Leading to Programmed Cell Death in Trypanosoma brucei

Trypanosomes are parasites that cycle between the insect host (procyclic form) and mammalian host (bloodstream form). These parasites lack conventional transcription regulation, including factors that induce the unfolded protein response (UPR). However, they possess a stress response mechanism, the spliced leader RNA silencing (SLS) pathway. SLS elicits shut-off of spliced leader RNA (SL RNA) transcription by perturbing the binding of the transcription factor tSNAP42 to its cognate promoter, thus eliminating trans-splicing of all mRNAs. Induction of endoplasmic reticulum (ER) stress in procyclic trypanosomes elicits changes in the transcriptome similar to those induced by conventional UPR found in other eukaryotes. The mechanism of up-regulation under ER stress is dependent on differential stabilization of mRNAs. The transcriptome changes are accompanied by ER dilation and elevation in the ER chaperone, BiP. Prolonged ER stress induces SLS pathway. RNAi silencing of SEC63, a factor that participates in protein translocation across the ER membrane, or SEC61, the translocation channel, also induces SLS. Silencing of these genes or prolonged ER stress led to programmed cell death (PCD), evident by exposure of phosphatidyl serine, DNA laddering, increase in reactive oxygen species (ROS) production, increase in cytoplasmic Ca2+, and decrease in mitochondrial membrane potential, as well as typical morphological changes observed by transmission electron microscopy (TEM). ER stress response is also induced in the bloodstream form and if the stress persists it leads to SLS. We propose that prolonged ER stress induces SLS, which serves as a unique death pathway, replacing the conventional caspase-mediated PCD observed in higher eukaryotes

Age-related testosterone declines can be detected in men’s fingernails

Testosterone plays multiple roles in the regulation of development, physiology, reproduction, and behavior. Age-related testosterone declines are expected in the population. However, measuring circulating testosterone is especially challenging since concentrations are labile, responding to social situations and challenges. Matrices that integrate long-term testosterone levels are therefore valuable as biomarkers of mean, as well as chronic exposures. Here we report on a simple method to extract and measure accumulated testosterone from human fingernails using commercial EIA kits. Further, we demonstrate known human testosterone sex and age trends. Our method is especially useful for quantifying testosterone in menâ s nails, where a small amount of matrix is required. Thus, this approach is a potential tool for biomonitoring endogenous as well as exogenous testosterone exposure. We suggest considering nails as an alternative matrix for quantifying other steroids as well.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Data from: Sex differences in the relationship between maternal and foetal glucocorticoids in a free-ranging large mammal

Description This registration contains the data and scripts used for the analysis in the manuscript "Sex differences in the relationship between maternal and neonate cortisol in a free-ranging large mammal" (https://doi.org/10.1101/2023.05.04.538920). All versions and additional material are posted on the OSF project page: https://osf.io/4ymc8/ Important to note: this is an updated registration from a previous version (www.osf.io/wynke). OSF currently does not allow to change the files that were uploaded previously, which is why we switched to Zenodo. Future updates to the dataset and scripts will take place here. Changes to previous version Following our review process at PCI Ecology, we made some changes (mostly additions) to the previous version. This includes the addition of more raw data. Changes to the previous version include: - We added the raw faecal data (“Raw_faecal_data.csv) along with a script (“Faecal exploration .R”), which loads the raw faecal datafile and does some minor investigations on it. These include checking whether the sampling time or day matter, and calculating a repeatability estimate. - In “Faecal exploration.R”, we highlight the outlier that we removed. - We have added the t-test reported in the manuscript to the script “Analysis.R”. - In “Analysis.R”, we now also run the analysis both with as well as without the outlier. We also have adapted our code to plot the outlier in the figure along with the other values. - We have updated the README file to include a description of both the data files and the scripts

Integrity of the N-terminal transcription domain of p53 is required for mutant p53 interference with drug-induced apoptosis

The present study examined whether the ability of mutant p53 to block apoptosis depended on its transcriptional activity. A core domain mutant p53 (143 Val to Ala), in which two N-terminal residues (22 and 23) essential for transactivation were also mutated (Leu to Glu and Trp to Ser, respectively), was examined. While p53 containing only the core mutation efficiently interfered with drug-induced apoptosis, further modification at the N-terminus abolished this blocking activity. Furthermore, expression of c-myc, a suggested target for core mutant p53 transactivation, was elevated in the core mutant p53-expressing cells, but was abolished in the presence of the transcription-deficient p53 core mutant. In addition, wild-type p53, mutated in the N-terminus (residues 22 and 23), was unable to induce apoptosis by itself. Nevertheless, it synergized with drugs in the induction of apoptosis. This suggests that the integrity of the N-terminus is essential for both the activity of wild-type p53 in apoptosis and for mutant p53-mediated block of drug-induced apoptosis. This supports the notion that core p53 mutants act via a gain of function mechanism

Data from: Towards the validation of endogenous steroid testing in wildlife hair

1. Hair is emerging as a popular tool to examine steroid hormone levels in wild mammals. The reliability of this approach, however, depends on an understanding of steroid hormone incorporation into hair as well as appropriate validations. 2. We reviewed studies that have examined steroid hormones in wildlife hair with the goal of summarizing the analytical, physiological, and biological evidence that this approach is meaningful. Accordingly, we differentiated among validations aimed at evaluating the reliability of the analytical method versus those designed to assess whether hormone levels in hair reflect physiologically meaningful processes in the target species. 3. Our literature survey revealed that endogenous steroids have been examined in hair from 42 species of non-human animals across 7 mammalian classes. Although the majority (85%) of 72 studies reported analytical validations of the method, physiological validations have only been reported for five species. Moreover, results of physiological validations were inconsistent among studies, highlighting the need for further research designed carefully to differentiate among the multiple purported models of steroid incorporation into hair in species with different types of hair and hair growth patterns. 4. To complement our review of published studies, we present new data supporting a positive relationship between levels of the steroid, cortisol, in hair and blood across eight mammalian species. In addition, we present novel results from a laboratory-based study showing variable hair growth in genetically identical laboratory mice that were kept under controlled conditions. 5. Synthesis and Applications: Collectively, this synthesis reveals substantial progress towards the validation of endocrine assays in hair from a variety of wildlife species. Further validations of other steroids, combined with appropriate physiological validations, would expand the potential applications of hair testing in wildlife research. As a key example, physiological data can provide mechanistic insight into species’ responses to change and may therefore contribute to conservation planning

Supplementary electronic data

Supplementary information describing LC-MS/MS conditions, blanks, and validation

Data from: Testosterone in ancient hair from an extinct species

Testosterone is a key regulator in vertebrate development, physiology, and behaviour. Whereas technology allows extraction of a wealth of genetic information from extant as well as extinct species, complimentary information on steroid hormone levels may add a social, sexual, and environmental context. Hair shafts have been previously used to sequence DNA from >50,000 14C years old Siberian woolly mammoths (Mammuthus primigenius). Hair-testing has also been used to measure endogenous steroids in multiple extant species. Here we use small quantities of woolly mammoth hair samples to measure testosterone, and a genomics-based approach to determine sex, in permafrost-preserved mammoths dated to circa 10-60 thousand 14C years. Our validated method opens up exciting opportunities to measure multiple steroids in keratinized tissues from extinct populations of mammals. This may be specifically applied to investigating life histories, including the extinct Quaternary megafauna populations whose remains are preserved in the permafrost throughout the northern hemisphere

Global variation in postoperative mortality and complications after cancer surgery: a multicentre, prospective cohort study in 82 countries

© 2021 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY-NC-ND 4.0 licenseBackground: 80% of individuals with cancer will require a surgical procedure, yet little comparative data exist on early outcomes in low-income and middle-income countries (LMICs). We compared postoperative outcomes in breast, colorectal, and gastric cancer surgery in hospitals worldwide, focusing on the effect of disease stage and complications on postoperative mortality. Methods: This was a multicentre, international prospective cohort study of consecutive adult patients undergoing surgery for primary breast, colorectal, or gastric cancer requiring a skin incision done under general or neuraxial anaesthesia. The primary outcome was death or major complication within 30 days of surgery. Multilevel logistic regression determined relationships within three-level nested models of patients within hospitals and countries. Hospital-level infrastructure effects were explored with three-way mediation analyses. This study was registered with ClinicalTrials.gov, NCT03471494. Findings: Between April 1, 2018, and Jan 31, 2019, we enrolled 15 958 patients from 428 hospitals in 82 countries (high income 9106 patients, 31 countries; upper-middle income 2721 patients, 23 countries; or lower-middle income 4131 patients, 28 countries). Patients in LMICs presented with more advanced disease compared with patients in high-income countries. 30-day mortality was higher for gastric cancer in low-income or lower-middle-income countries (adjusted odds ratio 3·72, 95% CI 1·70–8·16) and for colorectal cancer in low-income or lower-middle-income countries (4·59, 2·39–8·80) and upper-middle-income countries (2·06, 1·11–3·83). No difference in 30-day mortality was seen in breast cancer. The proportion of patients who died after a major complication was greatest in low-income or lower-middle-income countries (6·15, 3·26–11·59) and upper-middle-income countries (3·89, 2·08–7·29). Postoperative death after complications was partly explained by patient factors (60%) and partly by hospital or country (40%). The absence of consistently available postoperative care facilities was associated with seven to 10 more deaths per 100 major complications in LMICs. Cancer stage alone explained little of the early variation in mortality or postoperative complications. Interpretation: Higher levels of mortality after cancer surgery in LMICs was not fully explained by later presentation of disease. The capacity to rescue patients from surgical complications is a tangible opportunity for meaningful intervention. Early death after cancer surgery might be reduced by policies focusing on strengthening perioperative care systems to detect and intervene in common complications. Funding: National Institute for Health Research Global Health Research Unit