E2/E3-independent ubiquitin-like protein conjugation by Urm1 is directly coupled to cysteine persulfidation.

Post-translational modifications by ubiquitin-like proteins (UBLs) are essential for nearly all cellular processes. Ubiquitin-related modifier 1 (Urm1) is a unique UBL, which plays a key role in tRNA anticodon thiolation as a sulfur carrier protein (SCP) and is linked to the noncanonical E1 enzyme Uba4 (ubiquitin-like protein activator 4). While Urm1 has also been observed to conjugate to target proteins like other UBLs, the molecular mechanism of its attachment remains unknown. Here, we reconstitute the covalent attachment of thiocarboxylated Urm1 to various cellular target proteins in vitro, revealing that, unlike other known UBLs, this process is E2/E3-independent and requires oxidative stress. Furthermore, we present the crystal structures of the peroxiredoxin Ahp1 before and after the covalent attachment of Urm1. Surprisingly, we show that urmylation is accompanied by the transfer of sulfur to cysteine residues in the target proteins, also known as cysteine persulfidation. Our results illustrate the role of the Uba4-Urm1 system as a key evolutionary link between prokaryotic SCPs and the UBL modifications observed in modern eukaryotes.

Does sex modify the effect of pre-pandemic body mass index on the risk of Long COVID? Evidence from the longitudinal analysis of the Survey of Health, Ageing and Retirement in Europe.

BACKGROUND: Research on Long COVID risk factors is ongoing. High body mass index (BMI) may increase Long COVID risk, yet no evidence has been established regarding sex differences in the relationship between BMI and the risk of Long COVID. Investigating the nature of this relationship was the main objective of this study. METHODS: A population-based prospective study involving a sample of respondents aged 50 years and older (n = 4004) from 27 European countries that participated in the 2020 and 2021 Survey of Health, Ageing and Retirement in Europe's (SHARE) Corona Surveys and in Waves 7 and 8 of the main SHARE survey. Logistic regression models were estimated to produce unadjusted and adjusted estimates of the sex differences in the relationship between BMI and Long COVID. RESULTS: Linear relationship for females, with probability of Long COVID increasing with BMI (68% at BMI = 18, 93% at BMI = 45). Non-linear relationship for males, with probability of Long COVID of 27% at BMI = 18, 68% at BMI = 33, and 40% at BMI = 45. Relationships remained significant after adjusting for known Long COVID risk factors (age and COVID-19 hospitalization), presence of chronic diseases, and respondents' place of residence. CONCLUSION: Sex differences appear to play an important role in the relationship between BMI and risk of Long COVID. Overall, females were more likely to have Long COVID, regardless of their BMI. Males at the higher end of the BMI spectrum had a lower risk of Long COVID as opposed to their female counterparts. Sex-specific research is recommended for better understanding of Long COVID risk factors.

Association of outdoor air and noise pollution with unprovoked seizures and new onset epilepsy: A systematic review and meta-analysis.

Research has indicated that certain environmental exposures may increase the risk of unprovoked seizures and new onset epilepsy. This study aimed to synthesize the literature that has estimated the associations between short- and long-term exposure to outdoor air and noise pollution and the risk of unprovoked seizures and new onset epilepsy. We searched Embase, MEDLINE, Scopus, Web of Science, BIOSIS Previews, Latin American and Caribbean Health Sciences Literature, Proquest Dissertations and Theses, conference abstracts, and the gray literature and conducted citation tracing in June 2023. Observational and ecological studies assessing the associations of air and noise pollution with unprovoked seizures or new onset epilepsy were eligible. One reviewer extracted summary data. Using fixed and random effects models, we calculated the pooled risk ratios (RRs) for the studies assessing the associations between short-term exposure to air pollution and unprovoked seizures. Seventeen studies were included, 16 assessing the association of air pollution with seizures and one with epilepsy. Eight studies were pooled quantitatively. Ozone (O3; RR = .99, 95% confidence interval [CI] = .99-.99) and nitrogen dioxide (NO2) exposure adjusted for particulate matter (RR = 1.02, 95% CI = 1.01-1.02) on the same day, and carbon monoxide (CO) exposure 2 days prior (RR = 1.12, 95% CI = 1.02-1.22), were associated with seizure risk. A single study of air pollution and epilepsy did not report a significant association. The risk of bias and heterogeneity across studies was moderate or high. Short-term exposure to O3, NO2, and CO may affect the risk of seizures; however, the effect estimates for O3 and NO2 were minimal. Additional research should continue to explore these and the associations between outdoor air pollution and epilepsy and between noise pollution and seizures and epilepsy.

Incidence of First-Episode Status Epilepticus and Risk Factors in Ontario, Canada.

BACKGROUND: Status epilepticus (SE) is a neurological emergency characterized by prolonged seizures. However, the incidence of first-episode SE is unclear, as estimates vary greatly among studies. Additionally, SE risk factors have been insufficiently explored. Therefore, the objectives of this study were to estimate the incidence of first-episode SE in Ontario, Canada, and estimate the associations between potential sociodemographic and health-related risk factors and first-episode SE. METHODS: We conducted a population-based retrospective cohort study using linked health administrative datasets. We included individuals who completed Canada's 2006 Census long-form questionnaire, lived in Ontario, were between 18 and 105, and had no history of SE. A Cox proportional hazards regression model was used to estimate the hazard ratios for SE within three years associated with each potential risk factor. RESULTS: The final sample included 1,301,700 participants, 140 of whom were hospitalized or had an emergency department visit for first-episode SE during follow-up (3.5 per 100,000 person-years). Older age was the only significant sociodemographic SE risk factor (HR = 1.35, 95% CI = 1.33, 1.37), while health-related risk factors included alcohol or drug abuse (HR = 1.05, 95% CI = 1.02, 1.08), brain tumour or cancer (HR = 1.14, 95% CI = 1.12, 1.15), chronic kidney disease (HR = 1.32, 95% CI = 1.29, 1.36), dementia (HR = 1.42, 95% CI = 1.36, 1.48), diabetes (HR = 1.11, 95% CI = 1.09, 1.12), epilepsy or seizures (HR = 1.05, 95% CI = 1.01, 1.09) and stroke (HR = 1.08, 95% CI = 1.05, 1.11). CONCLUSION: The estimated incidence of SE in a sample of Ontario residents was 3.5 per 100,000 person-years. Older age and several comorbid conditions were associated with higher first-episode SE risk.

Relationship between multimorbidity, functional limitation, and quality of life among middle-aged and older adults: findings from the longitudinal analysis of the 2013-2020 Survey of Health, Ageing, and Retirement in Europe (SHARE).

PURPOSE: The increased burden of multimorbidity is restricting individuals' ability to live autonomously, leading to a poorer quality of life. This study estimated trajectories of functional limitation and quality of life among middle-aged (ages 50 to 64 years) and older (aged 65 years and older) individuals with and without multimorbidity. We also assessed differences in the relationship between these two trajectories by multimorbidity status and separately for each age cohort. METHODS: Data originated from the Survey of Health, Ageing, and Retirement in Europe (SHARE). In Luxembourg, data were obtained between 2013 and 2020, involving 1,585 respondents ≥ 50 years of age. Multimorbidity was defined as a self-reported diagnosis of two or more out of 16 chronic conditions; functional limitation was assessed by a combined (Instrumental) Activities of Daily Living (ADL/IADLI) scale; and to measure quality of life, we used the Control, Autonomy, Self-Realization, and Pleasure (CASP-12) scale. Latent growth curve modelling techniques were used to conduct the analysis where repeated measures of quality of life and functional limitation were treated as continuous and zero-inflated count variables, respectively. The model was assessed separately in each age cohort, controlling for the baseline covariates, and the estimates from the two cohorts were presented as components of a synthetic cohort covering the life course from the age of 50. RESULTS: Middle-aged and older adults living with multimorbidity experienced poorer quality of life throughout the life course and were at a higher risk of functional limitation than those without multimorbidity. At baseline, functional limitation had a negative impact on quality of life. Furthermore, among middle-aged adults without multimorbidity and older adults with multimorbidity, an increase in the number of functional limitations led to a decline in quality of life. These results imply that the impact of multimorbidity on functional limitation and quality of life may vary across the life course. CONCLUSION: Using novel methodological techniques, this study contributes to a better understanding of the longitudinal relationship between functional limitation and quality of life among individuals with and without multimorbidity and how this relationship changes across the life course. Our findings suggest that lowering the risk of having multimorbidity can decrease functional limitation and increase quality of life.

The effect modification of extreme temperatures on mental and behavior disorders by environmental factors and individual-level characteristics in Canada.

OBJECTIVE: Ambient extreme temperatures have been associated with mental and behavior disorders (MBDs). However, few studies have assesed whether vulnerability factors such as ambient air pollution, pre-existing mental health conditions and residential environmental factors increase susceptibility. This study aims to evaluate the associations between short-term variations in outdoor ambient extreme temperatures and MBD-related emergency department (ED) visits and how these associations are modified by vulnerability factors. METHODS: We conducted a case-crossover study of 9,958,759 MBD ED visits in Alberta and Ontario, Canada made between March 1st, 2004 and December 31st, 2020. Daily average temperature was assigned to individual cases with ED visits for MBD using gridded data at a 1 km × 1 km spatial resolution. Conditional logistic regression was used to estimate associations between extreme temperatures (i.e., risk of ED visit at the 2.5th percentile temperature for cold and 97.5th percentile temperature for heat for each health region compared to the minimal temperature risk) and MBD ED visits. Age, sex, pre-existing mental health conditions, ambient air pollution (i.e. PM2.5, NO2 and O3) and residential environmental factors (neighborhood deprivation, residential green space exposure and urbanization) were evaluated as potential effect modifiers. RESULTS: Cumulative exposure to extreme heat over 0-5 days (odds ratio [OR] = 1.145; 95% CI: 1.121-1.171) was associated with ED visits for any MBD. However, cumulative exposure to extreme cold was associated with lower risk of ED visits for any MBD (OR = 0.981; 95% CI: 0.976-0.987). We also found heat to be associated with ED visits for specific MBDs such as substance use disorders, dementia, neurotic disorders, schizophrenia and personality behavior disorder. Individuals with pre-existing mental health conditions, those exposed to higher daily concentrations of NO2 and O3 and those residing in neighborhoods with greater material and social deprivation were at higher risk of heat-related MBD ED visits. Increasing tree canopy coverage appeared to mitigate risks of the effect of heat on MBD ED visits. CONCLUSIONS: Findings provide evidence that the impacts of heat on MBD ED visits may vary across different vulnerability factors.

The role of multimorbidity and socio-economic characteristics as potential risk factors for Long Covid: evidence from the multilevel analysis of the Survey of Health, Ageing and Retirement in Europe's corona surveys (2020-2021).

BACKGROUND: A substantial proportion of individuals continue experiencing persistent symptoms following the acute stage of their Covid-19 illness. However, there is a shortage of population-based studies on Long Covid risk factors. OBJECTIVE: To estimate the prevalence of Long Covid in the population of middle-aged and older Europeans having contracted Covid-19 and to assess the role of multimorbidity and socio-economic characteristics as potential risk factors of Long Covid. METHODS: A population-based longitudinal prospective study involving a sample of respondents 50 years and older (n = 4,004) from 27 countries who participated in the 2020 and 2021 Survey of Health, Ageing and Retirement in Europe (SHARE), in particular the Corona Surveys. Analyses were conducted by a multilevel (random intercept) hurdle negative binomial model. RESULTS: Overall, 71.6% (95% confidence interval = 70.2-73.0%) of the individuals who contracted Covid-19 had at least one symptom of Long Covid up to 12 months after the infection, with an average of 3.06 (standard deviation = 1.88) symptoms. There were significant cross-country differences in the prevalence of Long Covid and number of symptoms. Higher education and being a man were associated with a lower risk of Long Covid, whilst being employed was associated with a higher risk of having Long Covid. Multimorbidity was associated with a higher number of symptoms and older age was associated with a lower number of symptoms. CONCLUSION: Our results provide evidence on the substantial burden of Long Covid in Europe. Individuals who contracted Covid-19 may require long-term support or further medical intervention, putting additional pressure on national health care systems.

Association between accuracy of weight perception and life satisfaction among adults with and without anxiety and mood disorders: a cross-sectional study of the 2015-2018 Canadian Community Health Survey.

BACKGROUND: Weight status and weight perception have a significant impact on life satisfaction. As overweight prevalence increases in Canada, it is important to understand how accuracy of weight perception (AWP) is associated with life satisfaction. This study explored the association between AWP and life satisfaction among Canadian adults with and without anxiety and/or mood disorders. METHODS: Using data from the 2015-2018 cycles of the Canadian Community Health Survey, an indicator of AWP was created to capture concordance between perceived weight and actual weight status. Univariate and multivariate Gaussian generalized linear models were assessed while stratifying by sex and presence of anxiety and/or mood disorders. RESULTS: Our sample included 88 814 males and 106 717 females. For both sexes, perceiving oneself as overweight or underweight, regardless of actual weight status, was associated with lower life satisfaction (ß = -0.93 to -0.30), compared to those who accurately perceived their weight as 'just about right'. Perceiving oneself as overweight or underweight was associated with more pronounced differences in life satisfaction scores in those with anxiety and/or mood disorders (ß = -1.49 to -0.26) than in those without these disorders (ß = -0.76 to -0.25). CONCLUSION: Weight perception is more indicative of life satisfaction than actual weight status, especially in those with anxiety and/or mood disorders.

HUG Domain Is Responsible for Active Dimer Stabilization in an NrdJd Ribonucleotide Reductase.

Ribonucleotide reductases (RNRs) catalyze the reduction of ribonucleotides to the corresponding deoxyribonucleotides. The catalytic activity of most RNRs depends on the formation of a dimer of the catalytic subunits. The active site is located at the interface, and part of the substrate binding site and regulatory mechanisms work across the subunit in the dimer. In this study, we describe and characterize a novel domain responsible for forming the catalytic dimer in several class II RNRs. The 3D structure of the class II RNR from Rhodobacter sphaeroides reveals a so far undescribed α-helical domain in the dimer interface, which is embracing the other subunit. Genetic removal of this HUG domain leads to a severe reduction of activity paired with reduced dimerization capability. In comparison with other described RNRs, the enzyme with this domain is less dependent on the presence of nucleotides to act as allosteric effectors in the formation of dimers. The HUG domain appears to serve as an interlock to keep the dimer intact and functional even at low enzyme and/or effector concentrations.

Trends in basal insulin prescribing in older adults with chronic kidney disease in Ontario, Canada: A population-based analysis from 2010 to 2020.

AIM: To examine trends in basal insulin prescribing in older adults with chronic kidney disease (CKD). MATERIALS AND METHODS: We conducted a population-based study of adults aged 66 years or older with treated diabetes from 1 January 2010 to 30 September 2020 in Ontario, Canada. We examined prevalent and incident prescriptions for human NPH, Levemir, glargine-100, Basaglar, glargine-300, and degludec insulin over 43 study intervals. We present trends in those with CKD, and in a subgroup, by estimated glomerular filtration rate (eGFR). To provide context for prescribing, we provide demographics, co-morbidities, and the healthcare utilization of included patients. RESULTS: In CKD, use of basal insulin was about 2-fold higher than in the general treated diabetes cohort. Prescriptions for NPH declined over time, while prescriptions for Levemir and glargine-100 increased until 2018 then decreased. Following drug formulary approval (September 2018), prescriptions for glargine-300 and degludec increased substantially. Incident prescriptions for basal insulin in CKD declined over time; however, in those with an eGFR of less than 30 ml/min/1.73m2 , rates remained stable. In recent years, rates of degludec and glargine-300 have rivalled glargine-100. CONCLUSIONS: In an era of new oral and injectable diabetes medications, the use of basal insulin has declined in older adults with CKD. However, in those with more advanced CKD, basal insulin, particularly newer analogues, remain a mainstay treatment.

Examining the prevalence and correlates of multimorbidity among community-dwelling older adults: cross-sectional evidence from the Canadian Longitudinal Study on Aging (CLSA) first-follow-up data.

INTRODUCTION: multimorbidity has become an increasingly important issue for many populations around the world, including Canada. The objectives of this study were to estimate the prevalence of multimorbidity at first follow-up and to identify factors associated with multimorbidity using data from the Canadian Longitudinal Study on Aging (CLSA). METHODS: this study included 27,701 community-dwelling participants in the first follow-up of the CLSA. Multimorbidity was operationalised using two definitions (Public Health and Primary Care), as well as the cut-points of two or more chronic conditions (MM2+) and three or more chronic conditions (MM3+). The prevalence of multimorbidity was calculated at first follow-up and multivariable regression models were used to identify correlates of multimorbidity occurrence. RESULTS: the prevalence of multimorbidity at first follow-up was 32.3% among males and 39.3% among females when using the MM2+ Public Health definition, whereas the prevalence was 67.2% among males and 75.8% among females when using the MM2+ Primary Care definition. Older age, lower alcohol consumption, lower physical activity levels, dissatisfaction with sleep quality, dissatisfaction with life and experiencing social limitations due to health conditions were significantly associated with increased odds of multimorbidity for both males and females, regardless of the definition of multimorbidity used. CONCLUSION: various sociodemographic, behavioural and psychosocial factors are associated with multimorbidity. Future research should continue to examine how the prevalence of multimorbidity changes with time and how these changes may be related to specific risk factors. This future research should be supplemented with studies examining the longitudinal impacts of multimorbidity over time.

Geographic inequalities in paediatric emergency department visits in Ontario and Alberta: a multilevel analysis of 2.5 million visits.

BACKGROUND: Research on intra- and inter-regional variations in emergency department (ED) visits among children can provide a better understanding of the patterns of ED utilization and further insight into how contextual features of the urban environment may be associated with these health events. Our objectives were to assess intra-urban and inter-urban variation in paediatric emergency department (PED) visits in census metropolitan areas (CMAs) in Ontario and Alberta, Canada and explore if contextual factors related to material and social deprivation, proximity to healthcare facilities, and supply of family physicians explain this variation. METHODS: A retrospective, population-based analysis of data on PED visits recorded between April 1, 2015 and March 31, 2017 was conducted. Random intercept multilevel regression models were constructed to quantify the intra- (between forward sortation areas [FSAs]) and inter- (between CMAs) variations in the rates of PED visits. RESULTS: In total, 2,537,442 PED visits were included in the study. The overall crude FSA-level rate of PED visits was 415.4 per 1,000 children population. Across CMAs, the crude rate of PED visits was highest in Thunder Bay, Ontario (771.6) and lowest in Windsor, Ontario (237.2). There was evidence of substantial intra- and inter-urban variation in the rates of PED visits. More socially deprived FSAs, FSAs with decreased proximity to healthcare facilities, and CMAs with a higher rate of family physicians per 1,000 children population had higher rates of PED visits. CONCLUSIONS: The variation in rates of PED visits across CMAs and FSAs cannot be fully accounted for by age and sex distributions, material and social deprivation, proximity to healthcare facilities, or supply of family physicians. There is a need to explore additional contextual factors to better understand why some metropolitan areas have higher rates of PED visits.

Associations between Major Health Behaviors and Sleep Problems: Results from the 2015, 2016, 2017 Canadian Community Health Survey.

BACKGROUND AND OBJECTIVES: Key health behaviors including cigarette smoking, alcohol consumption, fruit and vegetable (FV) consumption, and physical activity have been associated with sleep-related problems. This cross-sectional study describes sleep quality and duration by gender in a large adult population and examines whether health behavioral factors are associated with short/long sleep duration and sleep problems (difficulty initiating/maintaining sleep [DIMS], daytime sleepiness, and finding sleep refreshing). METHODS: Using Canadian Community Health Survey data from cycles 2015, 2016, and 2017, binary and multinomial logistic regression models were computed. RESULTS: Of the 44,911 respondents included, only half of respondents met the recommended sleep duration. Fifty-five percent of females and forty-one percent of males reported DIMS. Binge drinking was associated with increased DIMS, with the strongest relationship being among females reporting weekly binge drinking (odds ratio (OR) 2.03 [1.59,2.60]). Binge drinking was also associated with decreased odds of finding sleep refreshing among females only (OR 0.73 [0.56,0.96] in weekly binge drinkers). Compared to respondents who had never smoked, daily smokers had higher odds of short sleep (OR 1.50 [1.30,1.74] and OR 1.39 [1.21,1.60]; females and males, respectively). Similarly, former smokers had higher odds of DIMS (OR 1.18 [1.06,1.31]) and not finding sleep refreshing (OR 0.85 [0.77,0.95]), among females; similar OR among males. Increased FV consumption was associated with increased odds of finding sleep refreshing (OR 1.05 [1.03,1.07] and OR 1.06 [1.04,1.08] in females and males, respectively). CONCLUSION: There is a high prevalence of sleep problems among Canadians. Potential gender differences in the relationships between health behaviors and sleep problems warrant further research.

Underlying molecular alterations in human dihydrolipoamide dehydrogenase deficiency revealed by structural analyses of disease-causing enzyme variants.

Human dihydrolipoamide dehydrogenase (hLADH, hE3) deficiency (OMIM# 246900) is an often prematurely lethal genetic disease usually caused by inactive or partially inactive hE3 variants. Here we report the crystal structure of wild-type hE3 at an unprecedented high resolution of 1.75 Å and the structures of six disease-causing hE3 variants at resolutions ranging from 1.44 to 2.34 Å. P453L proved to be the most deleterious substitution in structure as aberrations extensively compromised the active site. The most prevalent G194C-hE3 variant primarily exhibited structural alterations close to the substitution site, whereas the nearby cofactor-binding residues were left unperturbed. The G426E substitution mainly interfered with the local charge distribution introducing dynamics to the substitution site in the dimer interface; G194C and G426E both led to minor structural changes. The R460G, R447G and I445M substitutions all perturbed a solvent accessible channel, the so-called H+/H2O channel, leading to the active site. Molecular pathomechanisms of enhanced reactive oxygen species (ROS) generation and impaired binding to multienzyme complexes were also addressed according to the structural data for the relevant mutations. In summary, we present here for the first time a comprehensive study that links three-dimensional structures of disease-causing hE3 variants to residual hLADH activities, altered capacities for ROS generation, compromised affinities for multienzyme complexes and eventually clinical symptoms. Our results may serve as useful starting points for future therapeutic intervention approaches.

Molecular Mechanism of Thymidylate Synthase Inhibition by N4-Hydroxy-dCMP in View of Spectrophotometric and Crystallographic Studies.

Novel evidence is presented allowing further clarification of the mechanism of the slow-binding thymidylate synthase (TS) inhibition by N4-hydroxy-dCMP (N4-OH-dCMP). Spectrophotometric monitoring documented time- and temperature-, and N4-OH-dCMP-dependent TS-catalyzed dihydrofolate production, accompanying the mouse enzyme incubation with N4-OH-dCMP and N5,10-methylenetetrahydrofolate, known to inactivate the enzyme by the covalent binding of the inhibitor, suggesting the demonstrated reaction to be uncoupled from the pyrimidine C(5) methylation. The latter was in accord with the hypothesis based on the previously presented structure of mouse TS (cf. PDB ID: 4EZ8), and with conclusions based on the present structure of the parasitic nematode Trichinella spiralis, both co-crystallized with N4-OH-dCMP and N5,10-methylenetetrahdrofolate. The crystal structure of the mouse TS-N4-OH-dCMP complex soaked with N5,10-methylenetetrahydrofolate revealed the reaction to run via a unique imidazolidine ring opening, leaving the one-carbon group bound to the N(10) atom, thus too distant from the pyrimidine C(5) atom to enable the electrophilic attack and methylene group transfer.

Interplay between DsbA1, DsbA2 and C8J_1298 Periplasmic Oxidoreductases of Campylobacter jejuni and Their Impact on Bacterial Physiology and Pathogenesis.

The bacterial proteins of the Dsb family catalyze the formation of disulfide bridges between cysteine residues that stabilize protein structures and ensure their proper functioning. Here, we report the detailed analysis of the Dsb pathway of Campylobacter jejuni. The oxidizing Dsb system of this pathogen is unique because it consists of two monomeric DsbAs (DsbA1 and DsbA2) and one dimeric bifunctional protein (C8J_1298). Previously, we showed that DsbA1 and C8J_1298 are redundant. Here, we unraveled the interaction between the two monomeric DsbAs by in vitro and in vivo experiments and by solving their structures and found that both monomeric DsbAs are dispensable proteins. Their structures confirmed that they are homologs of EcDsbL. The slight differences seen in the surface charge of the proteins do not affect the interaction with their redox partner. Comparative proteomics showed that several respiratory proteins, as well as periplasmic transport proteins, are targets of the Dsb system. Some of these, both donors and electron acceptors, are essential elements of the C. jejuni respiratory process under oxygen-limiting conditions in the host intestine. The data presented provide detailed information on the function of the C. jejuni Dsb system, identifying it as a potential target for novel antibacterial molecules.

Structural analysis of new compound heterozygous variants in PEPD gene identified in a patient with Prolidase Deficiency diagnosed by exome sequencing.

Prolidase Deficiency (PD) is an autosomal recessive rare disorder caused by loss or reduction of prolidase enzymatic activity due to variants in the PEPD gene. PD clinical features vary among affected individuals: skin ulcerations, recurrent infections, and developmental delay are common. In this study, we describe a 16-year-old boy with a mild PD phenotype comprising chronic eczema, recurrent infections and elevated IgE. Whole exome sequencing analysis revealed three PEPD variants: c.575T>C p.(Leu192Pro) inherited from the mother, and c.692_694del p.(Tyr231del) and c.1409G>A p.(Arg470His), both inherited from the father. The variant p.(Tyr231del) has been previously characterized by high-resolution X-ray structure analysis as altering protein dynamics/flexibility. In order to study the effects of the other two prolidase variants, we performed site directed mutagenesis purification and crystallization studies. A high-resolution X-ray structure could only be obtained for the p.(Arg470His) variant, which showed no significant structural differences in comparison to WT prolidase. On the other hand, the p.(Leu192Pro) variant led to significant protein destabilization. Hence, we conclude that the maternal p.(Leu192Pro) variant was likely causally associated with the proband´s disease, together with the known pathogenic paternal variant p.(Tyr231del). Our results demonstrated the utility of exome sequencing to perform diagnosis in PD cases with mild phenotype.

Extreme heat and paediatric emergency department visits in Southwestern Ontario.

OBJECTIVE: The risk of adverse health events is expected to increase with hotter temperatures, particularly among the most vulnerable groups such as elderly persons and children. The objective of this study was to assess the association between extreme heat and daily emergency department visits among children (0 to 17 years) in Southwestern Ontario. METHODS: We examined the average maximum temperature, relative humidity, and daily paediatric emergency department visits in June through August of 2002 to 2019. We reviewed emergency department visits from two academic hospitals. Daily meteorological data from the local weather station were obtained from Environment and Climate Change Canada. RESULTS: Extreme heat, defined as the 99th percentile of the maximum temperature distribution, occurred at 33.1°C and was associated with an overall 22% increase in emergency department visits, compared to the reference temperature of 21°C. This association was mostly found between the second and fifth day after the exposure, suggesting a slightly delayed effect. The results of the sub-group analysis indicate that the risk of an emergency department visit due to infectious disease increases by 35% and the most pronounced association was noted in children aged 1 to 12 years. CONCLUSIONS: Extreme heat is associated with an increased incidence of emergency department visits in children. As temperatures continue to increase, strategies to mitigate heat-related health risks among children should be developed.

Fatigue in young people with Duchenne muscular dystrophy.

AIM: To describe fatigue in Duchenne muscular dystrophy (DMD) from patients' and parents' perspectives and to explore risk factors for fatigue in children and adolescents with DMD. METHOD: A multicentre, cross-sectional study design was used. Seventy-one patients (all males; median age 12y, age range 5-17y) identified via the Canadian Neuromuscular Disease Registry, and their parents completed questionnaires. Subjective fatigue was assessed using the Pediatric Quality of Life Inventory Multidimensional Fatigue Scale by child self-report and parent proxy-report. RESULTS: Patients with DMD across ages and disease stages experienced greater fatigue compared to typically developing controls from published data. Sleep disturbance symptoms were associated with greater fatigue by child self-report (ρ=-0.42; p=0.003) and parent proxy-report (ρ=-0.51; p<0.001). Depressive symptoms were associated with greater fatigue by child self-report (ρ=-0.46; p<0.001) and parent proxy-report (ρ=-0.45; p<0.001). Lower functional ability was associated with greater fatigue by parent proxy-report (ρ=0.26; p=0.03). Physical activity level, and musculoskeletal, respiratory, and cardiac function were not associated with fatigue. INTERPRETATION: In paediatric DMD, sleep disturbance symptoms and depressive symptoms are potentially modifiable factors associated with fatigue, warranting additional investigation to facilitate the development of therapeutic strategies to reduce fatigue. WHAT THIS PAPER ADDS: Fatigue is a major issue in paediatric Duchenne muscular dystrophy (DMD) across ages and disease stages. Sleep disturbance and depressive symptoms are significantly associated with fatigue in paediatric DMD.

Structural Characterization of Glycerol Kinase from the Thermophilic Fungus Chaetomium thermophilum.

Glycerol is an organic compound that can be utilized as an alternative source of carbon by various organisms. One of the ways to assimilate glycerol by the cell is the phosphorylative catabolic pathway in which its activation is catalyzed by glycerol kinase (GK) and glycerol-3-phosphate (G3P) is formed. To date, several GK crystal structures from bacteria, archaea, and unicellular eukaryotic parasites have been solved. Herein, we present a series of crystal structures of GK from Chaetomium thermophilum (CtGK) in apo and glycerol-bound forms. In addition, we show the feasibility of an ADP-dependent glucokinase (ADPGK)-coupled enzymatic assay to measure the CtGK activity. New structures described in our work provide structural insights into the GK catalyzed reaction in the filamentous fungus and set the foundation for understanding the glycerol metabolism in eukaryotes.