Signaling by the integrated stress response kinase PKR is fine-tuned by dynamic clustering.

The double-stranded RNA sensor kinase PKR is one of four integrated stress response (ISR) sensor kinases that phosphorylate the α subunit of eukaryotic initiation factor 2 (eIF2α) in response to stress. The current model of PKR activation considers the formation of back-to-back PKR dimers as a prerequisite for signal propagation. Here we show that PKR signaling involves the assembly of dynamic PKR clusters. PKR clustering is driven by ligand binding to PKR's sensor domain and by front-to-front interfaces between PKR's kinase domains. PKR clusters are discrete, heterogeneous, autonomous coalescences that share some protein components with processing bodies. Strikingly, eIF2α is not recruited to PKR clusters, and PKR cluster disruption enhances eIF2α phosphorylation. Together, these results support a model in which PKR clustering may limit encounters between PKR and eIF2α to buffer downstream signaling and prevent the ISR from misfiring.

Hepatitis A outbreak associated with a food handler in Bizkaia, 2017. / Brote de hepatitis A asociado a un manipulador de alimentos en Bizkaia, 2017.

INTRODUCTION: The reporting of one case of hepatitis A in a food handler at a bakery and five cases in employees of a company after consuming products from the same bakery prompted an outbreak investigation. METHODS: Outbreak cases were defined as individuals with laboratory-confirmed hepatitis A (HAV) infection, with symptoms which started in June and who, during the incubation period, worked with the food handler and/or had close contact with him and/or consumed products from the bakery. Epidemiologic questionnaires were performed and blood samples were obtained to be tested for the presence of anti-hepatitis A antibodies. Molecular characterisation was carried out by PCR, sequencing of the VP1/2A region and phylogenetic analysis with the maximum likelihood estimation method, bootstrap 1000 (MEGA 7.0 software). RESULTS: A total of 14 primary hepatitis A cases were identified: eleven cases related to the consumption of products from the bakery, two cases among co-workers of the food handler, and one case was a household contact. All 12 sequenced viruses were genotype IA, matching one of the strains (RIVM-HAV16-090) responsible for the outbreaks occurring at that time in Europe, mostly affecting men who have sex with men. CONCLUSIONS: HAV vaccination of at-risk groups should be reinforced in order to prevent future outbreaks. Increasing the use of molecular typing in hepatitis A cases could improve the investigation of outbreaks, which can be expected to increase in the future because of decreasing immunity in the population.

Exposure to substances in the workplace and new-onset asthma: an international prospective population-based study (ECRHS-II).

BACKGROUND: The role of exposure to substances in the workplace in new-onset asthma is not well characterised in population-based studies. We therefore aimed to estimate the relative and attributable risks of new-onset asthma in relation to occupations, work-related exposures, and inhalation accidents. METHODS: We studied prospectively 6837 participants from 13 countries who previously took part in the European Community Respiratory Health Survey (1990-95) and did not report respiratory symptoms or a history of asthma at the time of the first study. Asthma was assessed by methacholine challenge test and by questionnaire data on asthma symptoms. Exposures were defined by high-risk occupations, an asthma-specific job exposure matrix with additional expert judgment, and through self-report of acute inhalation events. Relative risks for new onset asthma were calculated with log-binomial models adjusted for age, sex, smoking, and study centre. FINDINGS: A significant excess asthma risk was seen after exposure to substances known to cause occupational asthma (Relative risk=1.6, 95% CI 1.1-2.3, p=0.017). Risks were highest for asthma defined by bronchial hyper-reactivity in addition to symptoms (2.4, 1.3-4.6, p=0.008). Of common occupations, a significant excess risk of asthma was seen for nursing (2.2, 1.3-4.0, p=0.007). Asthma risk was also increased in participants who reported an acute symptomatic inhalation event such as fire, mixing cleaning products, or chemical spills (RR=3.3, 95% CI 1.0-11.1, p=0.051). The population-attributable risk for adult asthma due to occupational exposures ranged from 10% to 25%, equivalent to an incidence of new-onset occupational asthma of 250-300 cases per million people per year. INTERPRETATION: Occupational exposures account for a substantial proportion of adult asthma incidence. The increased risk of asthma after inhalation accidents suggests that workers who have such accidents should be monitored closely.

[Changes in the prevalence of asthma in the Spanish cohort of the European Community Respiratory Health Survey (ECRHS-II)]. / Cambios en la prevalencia de asma en la población española del Estudio de Salud Respiratoria de la Comunidad Europea (ECRHS-II).

OBJECTIVE: The rise in the prevalence of asthma in the second half of the 20th century has not been evenly distributed according to recent surveys. We assessed changes in the prevalence of asthma after a period of 9 to 10 years in a cohort of young adults in the Spanish arm of the European Community Respiratory Health Survey (ECRHS). MATERIAL AND METHODS: The ECRHS-II is a multicenter cohort study taking place in 27 centers around Europe, with Spanish centers located in Albacete, Barcelona, Galdakao, Huelva, and Oviedo. The ECRHS questionnaire was administered to individuals who had participated in the first phase of the survey; spirometry and methacholine challenge tests were also performed according to the published protocol. RESULTS: Among new smokers, the prevalence of wheezing in the last 12 months increased from 10% to 33%, while the frequency of phlegm production rose from 8% to 22% (P< .05). In ex-smokers, the prevalences of wheezing and phlegm production decreased from 21% to 12% and from 15% to 8%, respectively (P< .05). Symptom prevalences remained similar for never smokers, although the frequency of diagnosed asthma rose from 4% to 7% (P< .05). After adjusting for smoking, age, sex, and center, we found no significant differences in the frequency of symptoms or asthma, even when the phrase bronchial hyperreactivity was included in the definition. However, the rate of reported asthma rose annually by 0.34% (95% confidence interval [CI], 0.20%-0.48%), while diagnosed asthma rose by 0.26% (95% CI, 0.13%-0.39%) and treated asthma by 0.16% (95% CI, 0.07%-0.25%). CONCLUSIONS: Increased prevalence rates of asthma diagnosis and treatment have been detected, but the rates of reported symptoms have remained similar, consistent with the assumption that more persons are being classified as asthmatics.

Mitochondrial respiration links TOR complex 2 signaling to calcium regulation and autophagy.

The target of rapamycin (TOR) kinase is a conserved regulator of cell growth and functions within 2 different protein complexes, TORC1 and TORC2, where TORC2 positively controls macroautophagy/autophagy during amino acid starvation. Under these conditions, TORC2 signaling inhibits the activity of the calcium-regulated phosphatase calcineurin and promotes the general amino acid control (GAAC) response and autophagy. Here we demonstrate that TORC2 regulates calcineurin by controlling the respiratory activity of mitochondria. In particular, we find that mitochondrial oxidative stress affects the calcium channel regulatory protein Mid1, which we show is an essential upstream activator of calcineurin. Thus, these findings describe a novel regulation for autophagy that involves TORC2 signaling, mitochondrial respiration, and calcium homeostasis.

Stress-response transcription factors Msn2 and Msn4 couple TORC2-Ypk1 signaling and mitochondrial respiration to ATG8 gene expression and autophagy.

Macroautophagy/autophagy is a starvation and stress-induced catabolic process critical for cellular homeostasis and adaptation. Several Atg proteins are involved in the formation of the autophagosome and subsequent degradation of cytoplasmic components, a process termed autophagy flux. Additionally, the expression of several Atg proteins, in particular Atg8, is modulated transcriptionally, yet the regulatory mechanisms involved remain poorly understood. Here we demonstrate that the AGC kinase Ypk1, target of the rapamycin-insensitive TORC2 signaling pathway, controls ATG8 expression by repressing the heterodimeric Zinc-finger transcription factors Msn2 and Msn4. We find that Msn2 and Msn4 promote ATG8 expression downstream of the histone deacetylase complex (HDAC) subunit Ume6, a previously identified negative regulator of ATG8 expression. Moreover, we demonstrate that TORC2-Ypk1 signaling is functionally linked to distinct mitochondrial respiratory complexes. Surprisingly, we find that autophagy flux during amino acid starvation is also dependent upon Msn2-Msn4 activity, revealing a broad role for these transcription factors in the autophagy response.

Calcium channel regulator Mid1 links TORC2-mediated changes in mitochondrial respiration to autophagy.

Autophagy is a catabolic process that recycles cytoplasmic contents and is crucial for cell survival during stress. The target of rapamycin (TOR) kinase regulates autophagy as part of two distinct protein complexes, TORC1 and TORC2. TORC1 negatively regulates autophagy according to nitrogen availability. In contrast, TORC2 functions as a positive regulator of autophagy during amino acid starvation, via its target kinase Ypk1, by repressing the activity of the calcium-dependent phosphatase calcineurin and promoting the general amino acid control (GAAC) response. Precisely how TORC2-Ypk1 signaling regulates calcineurin within this pathway remains unknown. Here we demonstrate that activation of calcineurin requires Mid1, an endoplasmic reticulum-localized calcium channel regulatory protein implicated in the oxidative stress response. We find that normal mitochondrial respiration is perturbed in TORC2-Ypk1-deficient cells, which results in the accumulation of mitochondrial-derived reactive oxygen species that signal to Mid1 to activate calcineurin, thereby inhibiting the GAAC response and autophagy. These findings describe a novel pathway involving TORC2, mitochondrial oxidative stress, and calcium homeostasis for autophagy regulation.

[Epidemiology of accidents in a cohort of adults over 64 years old in the Autonomous Community of the Basque Country]. / Epidemiología de los accidentes en una cohorte de adultos mayores de 64 años de la Comunidad Autónoma del País Vasco.

INTRODUCTION: Accidents represent a significant health problem for elderly people. The objective of this study was to assess the incidence of accidents in over-64-year-olds in the Basque Country population, and to describe the clinical-epidemiological features leading to them. MATERIAL AND METHODS: This was a prospective cohort study of 15,192 non-institutionalised individuals over 64 years of age, conducted under the auspices of the Basque Sentinel Practice Network (Red Vigía) over one year. A questionnaire was completed for each accident. The rates and risks of accidents were calculated by sex and age group of the individuals who had the accidents. RESULTS: The rates of accidents were 46.52 and 81.87 per 1000 men and women, respectively. The most common type of accident was a fall (92%), and the most severe injuries were fractures (17%), with the risk of an accident being significantly higher in women and in the over-75-year-olds. CONCLUSIONS: These data reflect the scale of accidents in over-64-year-olds in the Basque Country. The most frequent accident was the fall, which represents a dramatic event among the elderly, being one of the main causes of injury, disability and institutionalisation among this population group.

Q Fever Outbreak among Workers at a Waste-Sorting Plant.

An outbreak of Q fever occurred in February-April 2014 among workers at a waste-sorting plant in Bilbao (Spain). The outbreak affected 58.5% of investigated employees, 47.2% as confirmed cases (PCR and/or serology) and 11.3% as probable cases (symptoms without laboratory confirmation). Only employees who had no-access to the waste processing areas of the plant were not affected and incidence of infection was significantly higher among workers not using respiratory protection masks. Detection by qPCR of Coxiella burnetii in dust collected from surfaces of the plant facilities confirmed exposure of workers inside the plant. Animal remains sporadically detected among the residues received for waste-sorting were the most probable source of infection. After cleaning and disinfection, all environmental samples tested negative. Personal protection measures were reinforced and made compulsory for the staff and actions were taken to raise farmers' awareness of the biological risk of discharging animal carcasses as urban waste.

Evaluation of specific occupational asthma risks in a community-based study with special reference to single and multiple exposures.

OBJECTIVES: To compare two job exposure matrices (JEMs) for the evaluation of asthma risks related to specific occupational exposures in a community-based study. METHODS: A questionnaire on self-reported asthma, respiratory symptoms and current occupation was sent to the participants of the European Community Respiratory Health Survey in five areas in Spain. Both an asthma-specific JEM, including expert judgment steps and a general JEM, were applied to occupational codes. Risks of current asthma symptoms and wheeze in the last year associated with the obtained exposure estimates were evaluated. Correlations between specific exposures were investigated using explanatory factor analysis. RESULTS: Occupational exposures to the high-molecular-weight (MW) agents flour dust, enzymes, mites and animal-derived proteins as obtained by the asthma-specific JEM were positively associated with asthma outcomes. The effect of additional expert judgment steps was limited. High exposures to biological dust assessed by the general JEM without expert judgment was also associated with asthma. Many of the exposed individuals worked in environments with multiple exposures. CONCLUSIONS: Asthma risks associated with occupational exposures to specific high-MW agents could be identified from a population-based study using an asthma-specific JEM. Application of JEMs can be a useful tool to estimate asthma risks attributable to specific occupational exposures in the general population. However, these specific exposure risks should be interpreted in connection with the whole of concomitant exposures constituting the work environment.

Smoking habit, respiratory symptoms and lung function in young adults.

BACKGROUND: Smoking is the primary cause of deterioration in forced expiratory volume (FEV(1)) and the development of chronic obstructive lung disease. This study assessed the independent association of smoking with respiratory symptoms and lung function in young adults who took part in the European Community Respiratory Health Survey (ECRHS-I). METHODS: Cross-sectional multi-centre survey of a general population of young adults aged 20(44 years in the ECRHS(I conducted in five Spanish centres. Several groups were created in an exclusive and descendent manner from the subjects who completed the questionnaire in accordance with how they had answered the questions: asthma-related symptoms; chronic bronchitis symptoms; minor respiratory symptoms; chronic cough; and no respiratory symptoms. Among a subset of the population, forced spirometry tests were performed. Linear and logistical regression models were used to assess the relationship of smoking in the presence of symptoms and its impact on lung function, adjusted by other important variables. RESULTS: The prevalence of respiratory symptoms was higher among smokers. After adjusting for geographical area, total IgE, age, sex, and FEV(1), smoking was associated with an increased risk of chronic bronchitis and other respiratory symptoms. These risks increased with increasing number of cigarettes smoked per day. A deterioration of FEV(1) and the FEV(1)/FVC ratio was also directly associated with the number of cigarettes smoked per day. CONCLUSION: Even among young adults, smoking confers a high risk of developing a number of respiratory symptoms and the deterioration of the ventilatory function.