Regulation of nuclear INF2 promotes actin polymerization and modulates MRTF-A subcellular localization and activity

Actin filaments are a fundamental component of the cytoskeleton. In eukaryotes, dynamic actin rearrangement plays a crucial part in cellular processes such as morphogenesis, adhesion, cell motility, cytokinesis and intracellular vesicle transport. Numerous aspects of actin dynamics in the cytoplasm of eukaryotic cells have been studied intensely over the past decades. Those studies revealed a very detailed knowledge about the structure and function of actin filaments as well as about the underlying mechanisms of F-actin formation. Though actin and proteins involved in actin assembly or disassembly have also been detected in the nuclei of many different eukaryotic cells lines, the detailed regulation and function of actin in the nuclear compartment is poorly defined. Monomeric nuclear actin was identified to participate in specific events such as transcriptional regulation or chromatin remodeling. Nevertheless, the existence and role of filamentous actin inside the nucleus has been controversially debated for years. Quite recently, specific actin probes have been described which enabled credible visualization of nuclear F-actin structures and provided a first insight into the regulation and function of actin polymerization in the nucleus. For example, a role for nuclear F-actin in response to DNA damage and efficient DNA repair as well as in the regulation of the SRF coactivator MRTF-A has been reported. Both events were shown to involve the assembly of nuclear actin filaments mediated by members of the formin family of actin nucleators. In this work, we provide evidence of a nuclear function of the disease associated formin INF2. We identified that activation of endogenous INF2 in the nucleus by means of INF2-DID-NLS or INF2-DAD-NLS expression mediated release of autoinhibition promotes the assembly of a nuclear F-actin network. We further observed that INF2 mediated nuclear actin rearrangement efficiently regulates the translocation and activity of MRTF-A. Moreover, by deletion of INF2 using the CRISPR/Cas9 system as well as by siRNA mediated INF2 knockdown we could show that INF2-DAD-NLS driven nuclear F-actin formation is primarily dependent on the presence of endogenous INF2. However, our data suggest concomitant modulation of nuclear mDia activity upon the release of INF2 autoinhibition in the nucleus. This study provides evidence for a role of the formin INF2 in the promotion and the formation of a nuclear actin network and thereby regulating the subcellular localization of MRTF-A and subsequent alteration of MRTF/SRF transcriptional activity

Differential effects of TbSec24 isoforms on Golgi protein localization

Trotz intensiver Erforschung des Golgi Apparates konnte der genaue Mechanismus für dessen Biogenese und Duplizierung sowie für dessen Vererbung an die Tochterzellen noch nicht vollständig entschlüsselt werden. Bisherige Untersuchungen am einzelligen Parasiten Trypanosoma brucei haben ergeben, daß in diesem Organismus die Komponenten des neuen Golgi sowohl vom bereits bestehenden Golgi, als auch von der neu gebildeten ER Austrittsstelle abstammen. Die einzelnen Golgi-Bestandteile lagern sich dabei geordnet an jener Stelle zusammen, an welcher der neue Golgi gebildet werden soll. Die vorliegende Arbeit soll weitere Aspekte der Synthese und Vererbung des Golgi Apparates in der prozyklischen Form von T. brucei aufzeigen. Im Speziellen wird hier untersucht, ob verschiedene Golgi-Komponenten selektiv für ihren Transport zum Golgi ausgewählt werden. Der Transport vom Endoplasmatischen Retikulum zum Golgi erfolgt mittels COPII Transportvesikel. Ein wesentlicher Bestandteil dieser Vesikel ist das Protein Sec24, von dem T. brucei zwei Isoformen, nämlich TbSec24.1 und TbSec24.2, besitzt. In dieser Studie wird jeweils eine der beiden TbSec24 Isoformen mittels RNA-Interferenz ausgeschaltet. Es zeigt sich, daß sowohl das Fehlen von TbSec24.1, als auch von TbSec24.2, zu einer verlangsamten Zellteilung, bis hin zu einem kompletten Arrest des Zellzyklus führt. Dabei kommt es jedoch zu keinerlei Abnormitäten in Bezug auf die einzelnen Stadien des Zellzyklus. Mittels Immunfluoreszenz-Mikroskopie wird klar, daß beide TbSec24 Isoformen einen selektiven Einfluß auf die Rekrutierung der Golgi Proteine TbGRIP70, Tbε-COP und TbGRASP zum Golgi Komplex ausüben. Eine Abnahme von TbSec24.1 in der Zelle führt dazu, daß TbGRASP nicht mehr am Golgi Apparat detektiert werden kann. Umgekehrt jedoch zeigt eine verminderte Expression von TbSec24.2 keinerlei derartigen Auswirkungen. Die Untersuchung des Aufenthaltsortes der Golgi Marker TbGRIP70 und Tbε-COP ergibt keine Veränderung, weder nach beeinträchtigter Expression von TbSec24.1, noch von TbSec24.2. Eine Detektion von TbGRIP70 ist nach verminderter TbSec24.1 Expression allerdings nur noch an jenen Golgi Apparaten möglich, welche mit einer kürzlich entdecken ‚Bilobe‘-förmigen Struktur assoziiert vorliegen. Zusätzlich zeigen wir noch die Reversibilität sämtlicher aufgetretener Phänotypen nach dem Abschalten der RNA-Interferenz.Despite intense research, the precise mechanisms of Golgi biogenesis are still unclear. In the simple eukaryote Trypanosoma brucei, Golgi biogenesis was suggested to require a coordinated supply of components from both the old Golgi and the new ER exit site. These components are then delivered to the site of the new Golgi. For studying further aspects of building a new Golgi in T. brucei, it is crucial to know how Golgi resident proteins are selected for transport to the Golgi. ER-to-Golgi transport is mediated by COPII vesicles. T. brucei has two different isoforms of the COPII component TbSec24 (TbSec24.1 and TbSec24.2). In this study RNA interference (RNAi) is used to silence expression of either TbSec24 isoform in the procyclic form of T. brucei. Cells show decelerated cell growth after depletion of either TbSec24.1 or TbSec24.2, but reveal no obvious abnormalities in terms of cell cycle progression. It is shown by immunofluorescence microscopy that TbSec24.1 depletion leads to a particularly striking mislocalization of the Golgi marker TbGRASP, whereas the localization of TbGRASP after depletion of TbSec24.2 remains unaffected. TbGRIP70 and Tbε-COP maintain their distinct Golgi localization after induction of RNAi to either TbSec24.1 or TbSec24.2, though TbGRIP70 is lost from non-bilobe Golgi upon depletion of TbSec24.1. The bilobe is a novel structure thought to be involved in Golgi biogenesis. The observed phenotypic effects are fully reversible upon relaxation of the RNAi silencing. These data provide evidence for a TbSec24 isoform-specific selective mechanism of sorting Golgi resident proteins in the early secretory pathway

Active trachoma and community use of sanitation, Ethiopia.

OBJECTIVE: To investigate, in Amhara, Ethiopia, the association between prevalence of active trachoma among children aged 1-9 years and community sanitation usage. METHODS: Between 2011 and 2014, prevalence of trachoma and household pit latrine usage were measured in five population-based cross-sectional surveys. Data on observed indicators of latrine use were aggregated into a measure of community sanitation usage calculated as the proportion of households with a latrine in use. All household members were examined for clinical signs, i.e. trachomatous inflammation, follicular and/or intense, indicative of active trachoma. Multilevel logistic regression was used to estimate prevalence odds ratios (OR) and 95% confidence intervals (CI), adjusting for community, household and individual factors, and to evaluate modification by household latrine use and water access. FINDINGS: In surveyed areas, prevalence of active trachoma among children was estimated to be 29% (95% CI: 28-30) and mean community sanitation usage was 47% (95% CI: 45-48). Despite significant modification (p < 0.0001), no pattern in stratified ORs was detected. Summarizing across strata, community sanitation usage values of 60 to < 80% and ≥ 80% were associated with lower prevalence odds of active trachoma, compared with community sanitation usage of < 20% (OR: 0.76; 95% CI: 0.57-1.03 and OR: 0.67; 95% CI: 0.48-0.95, respectively). CONCLUSION: In Amhara, Ethiopia, a negative correlation was observed between community sanitation usage and prevalence of active trachoma among children, highlighting the need for continued efforts to encourage higher levels of sanitation usage and to support sustained use throughout the community, not simply at the household level

Association of community sanitation usage with soil-transmitted helminth infections among school-aged children in Amhara Region, Ethiopia.

BACKGROUND: Globally, in 2010, approximately 1.5 billion people were infected with at least one species of soil-transmitted helminth (STH), Ascaris lumbricoides, Trichuris trichiura, hookworm (Ancylostoma duodenale and Necator americanus). Infection occurs through ingestion or contact (hookworm) with eggs or larvae in the environment from fecal contamination. To control these infections, the World Health Organization recommends periodic mass treatment of at-risk populations with deworming drugs. Prevention of these infections typically relies on improved excreta containment and disposal. Most evidence of the relationship between sanitation and STH has focused on household-level access or usage, rather than community-level sanitation usage. We examined the association between the proportion of households in a community with latrines in use and prevalence of STH infections among school-aged children. METHODS: Data on STH prevalence and household latrine usage were obtained during four population-based, cross-sectional surveys conducted between 2011 and 2014 in Amhara, Ethiopia. Multilevel regression was used to estimate the association between the proportion of households in the community with latrines in use and presence of STH infection, indicated by > 0 eggs in stool samples from children 6-15 years old. RESULTS: Prevalence of STH infection was estimated as 22% (95% CI: 20-24%), 14% (95% CI: 13-16%), and 4% (95% CI: 4-5%) for hookworm, A. lumbricoides, and T. trichiura, respectively. Adjusting for individual, household, and community characteristics, hookworm prevalence was not associated with community sanitation usage. Trichuris trichuria prevalence was higher in communities with sanitation usage ≥ 60% versus sanitation usage < 20%. Association of community sanitation usage with A. lumbricoides prevalence depended on household sanitation. Community sanitation usage was not associated with A. lumbricoides prevalence among households with latrines in use. Among households without latrines in use, A. lumbricoides prevalence was higher comparing communities with sanitation usage ≥ 60% versus < 20%. Households with a latrine in use had lower prevalence of A. lumbricoides compared to households without latrines in use only in communities where sanitation usage was ≥ 80%. CONCLUSIONS: We found no evidence of a protective association between community sanitation usage and STH infection. The relationship between STH infection and community sanitation usage may be complex and requires further study

A smooth tubercle bacillus from Ethiopia phylogenetically close to the Mycobacterium tuberculosis complex

The Mycobacterium tuberculosis complex (MTBC) includes several human- and animal-adapted pathogens. It is thought to have originated in East Africa from a recombinogenic Mycobacterium canettii-like ancestral pool. Here, we describe the discovery of a clinical tuberculosis strain isolated in Ethiopia that shares archetypal phenotypic and genomic features of M. canettii strains, but represents a phylogenetic branch much closer to the MTBC clade than to the M. canettii strains. Analysis of genomic traces of horizontal gene transfer in this isolate and previously identified M. canettii strains indicates a persistent albeit decreased recombinogenic lifestyle near the emergence of the MTBC. Our findings support that the MTBC emergence from its putative free-living M. canettii-like progenitor is evolutionarily very recent, and suggest the existence of a continuum of further extant derivatives from ancestral stages, close to the root of the MTBC, along the Great Rift Valley

Mapping local patterns of childhood overweight and wasting in low- and middle-income countries between 2000 and 2017

A double burden of malnutrition occurs when individuals, household members or communities experience both undernutrition and overweight. Here, we show geospatial estimates of overweight and wasting prevalence among children under 5 years of age in 105 low- and middle-income countries (LMICs) from 2000 to 2017 and aggregate these to policy-relevant administrative units. Wasting decreased overall across LMICs between 2000 and 2017, from 8.4% (62.3 (55.1–70.8) million) to 6.4% (58.3 (47.6–70.7) million), but is predicted to remain above the World Health Organization’s Global Nutrition Target of <5% in over half of LMICs by 2025. Prevalence of overweight increased from 5.2% (30 (22.8–38.5) million) in 2000 to 6.0% (55.5 (44.8–67.9) million) children aged under 5 years in 2017. Areas most affected by double burden of malnutrition were located in Indonesia, Thailand, southeastern China, Botswana, Cameroon and central Nigeria. Our estimates provide a new perspective to researchers, policy makers and public health agencies in their efforts to address this global childhood syndemic

Mapping 123 million neonatal, infant and child deaths between 2000 and 2017

Since 2000, many countries have achieved considerable success in improving child survival, but localized progress remains unclear. To inform efforts towards United Nations Sustainable Development Goal 3.2—to end preventable child deaths by 2030—we need consistently estimated data at the subnational level regarding child mortality rates and trends. Here we quantified, for the period 2000–2017, the subnational variation in mortality rates and number of deaths of neonates, infants and children under 5 years of age within 99 low- and middle-income countries using a geostatistical survival model. We estimated that 32% of children under 5 in these countries lived in districts that had attained rates of 25 or fewer child deaths per 1,000 live births by 2017, and that 58% of child deaths between 2000 and 2017 in these countries could have been averted in the absence of geographical inequality. This study enables the identification of high-mortality clusters, patterns of progress and geographical inequalities to inform appropriate investments and implementations that will help to improve the health of all populations

Global injury morbidity and mortality from 1990 to 2017 : results from the Global Burden of Disease Study 2017

Correction:Background Past research in population health trends has shown that injuries form a substantial burden of population health loss. Regular updates to injury burden assessments are critical. We report Global Burden of Disease (GBD) 2017 Study estimates on morbidity and mortality for all injuries. Methods We reviewed results for injuries from the GBD 2017 study. GBD 2017 measured injury-specific mortality and years of life lost (YLLs) using the Cause of Death Ensemble model. To measure non-fatal injuries, GBD 2017 modelled injury-specific incidence and converted this to prevalence and years lived with disability (YLDs). YLLs and YLDs were summed to calculate disability-adjusted life years (DALYs). Findings In 1990, there were 4 260 493 (4 085 700 to 4 396 138) injury deaths, which increased to 4 484 722 (4 332 010 to 4 585 554) deaths in 2017, while age-standardised mortality decreased from 1079 (1073 to 1086) to 738 (730 to 745) per 100 000. In 1990, there were 354 064 302 (95% uncertainty interval: 338 174 876 to 371 610 802) new cases of injury globally, which increased to 520 710 288 (493 430 247 to 547 988 635) new cases in 2017. During this time, age-standardised incidence decreased non-significantly from 6824 (6534 to 7147) to 6763 (6412 to 7118) per 100 000. Between 1990 and 2017, age-standardised DALYs decreased from 4947 (4655 to 5233) per 100 000 to 3267 (3058 to 3505). Interpretation Injuries are an important cause of health loss globally, though mortality has declined between 1990 and 2017. Future research in injury burden should focus on prevention in high-burden populations, improving data collection and ensuring access to medical care.Peer reviewe

Mapping local patterns of childhood overweight and wasting in low- and middle-income countries between 2000 and 2017

A double burden of malnutrition occurs when individuals, household members or communities experience both undernutrition and overweight. Here, we show geospatial estimates of overweight and wasting prevalence among children under 5 years of age in 105 low- and middle-income countries (LMICs) from 2000 to 2017 and aggregate these to policy-relevant administrative units. Wasting decreased overall across LMICs between 2000 and 2017, from 8.4% (62.3 (55.1–70.8) million) to 6.4% (58.3 (47.6–70.7) million), but is predicted to remain above the World Health Organization’s Global Nutrition Target of <5% in over half of LMICs by 2025. Prevalence of overweight increased from 5.2% (30 (22.8–38.5) million) in 2000 to 6.0% (55.5 (44.8–67.9) million) children aged under 5 years in 2017. Areas most affected by double burden of malnutrition were located in Indonesia, Thailand, southeastern China, Botswana, Cameroon and central Nigeria. Our estimates provide a new perspective to researchers, policy makers and public health agencies in their efforts to address this global childhood syndemic