The social and organisational factors shaping acceptability of a self-management education and exercise intervention for people with hip or knee osteoarthritis in Greenland.

This study aimed to explore the experiences and perspectives of people with osteoarthritis attending the "Osteoarthritis School" (OA School) in Nuuk, Greenland to generate insights and lessons that can inform the development of self-management education and exercise interventions for people with other lifestyle conditions in a Greenland context. We conducted a qualitative interpretive description (ID) study based on ten semi-structured interviews with people with hip or knee osteoarthritis. Interviews were audio-recorded, transcribed, and coded. Using ID, we identified three themes: 1) perceptions and experiences of how the OA School intervention was organised (time and place); 2) perspectives and experiences of the education and exercise components (social factors, motivation, and education); and 3) significant change stories (physical and mental improvements and increased knowledge of OA). Social and organisational factors, such as working out with peers and the time and place of the intervention, influenced the participants' acceptance of the OA School intervention. Knowledge from this study will help us gain insight into what to address when developing future self-management education and exercise interventions in the Greenlandic healthcare system.

Quality of care among patients diagnosed with atrial fibrillation in Greenland.

This cross-sectional study sought to assess the prevalence of atrial fibrillation (AF) diagnosis in Greenland among various age groups and examine the corresponding quality of care. We collected data from Greenland's electronic medical records and evaluated the quality of care using six internationally recommended indicators, which are: percentage of AF patients with an assessment of smoking status within the previous year, an assessment of body mass index within the previous year, assessment of blood pressure within the previous year, measurement of thyroid stimulating hormone (TSH), treatment with an anticoagulant and percentage of patients with a measurement of serum-creatinine. We found the prevalence of AF among patients aged 20 years or older in Greenland to be 1.75% (95% CI 1.62-1.88). We found an increasing prevalence of AF with age and a greater proportion of men than women until the age of 74 years. Our study suggests that the associated quality of care could be higher as the requirement of only one of the six quality indicators was met. A lack of registration may partly explain this, and initiatives to improve the quality of care are recommended.

Living with chronic obstructive pulmonary disease or type 2 diabetes in Greenland - a qualitative interpretive description study.

Non-communicable diseases such as chronic obstructive pulmonary disease (COPD) and type 2 diabetes mellitus (T2D) represent major challenges for health systems all over the world. In an interview study, we explored patient experiences and perspectives of being diagnosed and living with COPD or T2D in Greenland. Participants (n = 24) were selected by purposeful sampling and recruited by phone. We conducted individual semi-structured interviews at the National Hospital in Nuuk and the four regional hospitals. Interviews were audio-recorded, transcribed verbatim, and analysed using interpretive description. Three themes emerged: shock and shame on receiving the diagnosis, coping with a changed life, and varying needs for care and communication. We found that being diagnosed with COPD or T2D required a rapid change in the participants' everyday lives and lifestyle behaviours. Some self-managed their disease well and were able to transfer their knowledge and integrate it into their daily lives, while others struggled to make lifestyle changes. Additionally, living with COPD or T2D could be related to silence and shame. The findings contribute to a better understanding of living with COPD or T2D in the Arctic region and the development of future, culturally-adapted patient education initiatives.

Low skeletal muscle mass and liver fibrosis in children with cerebral palsy.

The purpose of the study was to conduct a nutritional and metabolic assessment of children with cerebral palsy, including an investigation of liver status, body composition, and bone mineral density. In this cross-sectional study we included 22 children with cerebral palsy. By using ultrasound, transient elastography, dual x-ray absorptiometry (DXA) scan, blood samples, anthropometric measurements, and a three-day diet registration, the nutritional and metabolic status was evaluated. Liver fibrosis and steatosis were found in four patients (18.2%), all with severe motor impairments, low skeletal muscle mass, and epilepsy. All patients with liver involvement had normal liver-related blood samples. Decreased bone mineral density was found in 26.3%, and 91.0% had low skeletal muscle mass. Fat mass and muscle mass were significantly lower in the patients with severe motor impairments compared to the patients with less severe motor impairments. Within the children classified as 'underweight' or 'normal' according to body mass index, body fat determined by DXA scan was normal or high in 50% of these patients. CONCLUSIONS: This study is the first to report liver fibrosis and steatosis in children with cerebral palsy. Possible causes of liver fibrosis and/or steatosis are altered body composition with low skeletal muscle mass, decreased mobility and medical drug intake. Further investigations of liver involvement and risk factors are needed. WHAT IS KNOWN: • Children and adolescents with cerebral palsy are at risk of malnutrition and altered body composition, both of which can lead to fatty liver disease. • It is unknown whether children with cerebral palsy are at increased risk of metabolic disturbances such as fatty liver disease. WHAT IS NEW: • Altered body composition and low skeletal muscle mass, regardless of ambulation is present in 91% of the children with cerebral palsy. • Liver fibrosis and/or steatosis were found in 18.2% of the patients. Possible causes are altered body composition, decreased mobility and medical drug intake.

Can a modified ketogenic diet be a nutritional strategy for patients with McArdle disease? Results from a randomized, single-blind, placebo-controlled, cross-over study.

BACKGROUND: McArdle disease is caused by myophosphorylase deficiency leading to blocked glycogenolysis in skeletal muscle. Consequently, individuals with McArdle disease have intolerance to physical activity, muscle fatigue, and pain. These symptoms vary according to the availability of alternative fuels for muscle contraction. In theory, a modified ketogenic diet (mKD) can provide alternative fuels in the form of ketone bodies and potentially boost fat oxidation. METHODS: This randomized, single-blind, placebo-controlled, cross-over study aimed to investigate if a mKD improves exercise capacity in individuals with McArdle disease. Participants were randomized to follow a mKD (75-80% fat, 15% protein, 5-10% carbohydrates) or placebo diet (PD) first for three weeks, followed by a wash-out period, and then the opposite diet. The primary outcome was change in heart rate during constant-load cycling. Secondary outcomes included change in plasma metabolites, perceived exertion, indirect calorimetry measures, maximal exercise capacity, and patient-reported outcomes. RESULTS: Fifteen out of 20 patients with genetically verified McArdle disease completed all study visits, and 14 were included in the data analyses. We found that the mKD induced a metabolic shift towards increased fat oxidation (∼60% increase), and a 19-fold increase in plasma ß-hydroxybutyrate (p < 0.05). The mKD did not improve heart rate responses during constant-load cycling but did improve patient-reported outcomes and maximal exercise capacity (∼20% increase) compared to the PD. CONCLUSION: The mKD did not alleviate all McArdle disease-related symptoms but did induce some positive changes. To date, no satisfactory treatment options exist other than exercise training. To that end, a mKD can be a possible nutritional strategy for some individuals with McArdle disease who are motivated to undertake a restrictive diet. CLINICAL TRIAL REGISTRATION: clinical trials.gov: NCT04044508.

High burden of symptoms reported among patients diagnosed with chronic obstructive pulmonary disease (COPD) in Greenland after introducing the COPD Assessment Test in clinical practice.

The aim was to test the internal consistency of the Greenlandic version of the COPD Assessment Test (CAT) questionnaire and to estimate the symptom burden in patients with chronic obstructive pulmonary disease (COPD) in Greenland using the CAT questionnaire. A Greenlandic version of the CAT questionnaire was developed including forward translation, reconciliation, backwards translation, and pilot test. Afterwards, a cross-sectional study of patients with COPD was conducted. The internal consistency assessed by the Cronbach α coefficient was 0.823 for the Greenlandic version of the questionnaire (n = 103). The CAT was negatively correlated to spirometry values and current smoking. In the cross-sectional study (n = 250), 81.1% of the patients experienced a high symptom burden (≥10). The main CAT score was 17 (range 0-38). The CAT was used in 9 out of 17 towns in Greenland. The Greenlandic version of the CAT questionnaire demonstrated a good internal consistency. We observed a high burden of symptoms associated with reduced lung function and active smoking status among patient diagnosed with COPD in Greenland. The questionnaire can be used in clinical practice for assessment of symptom burden in patients with COPD in Greenland and may help to increase focus on symptom control and quality of care.

Low Prevalence of Chronic Obstructive Pulmonary Disease in Greenland-A Call for Increased Focus on the Importance of Diagnosis Coding.

The aim of this study was to estimate the prevalence of patients diagnosed with chronic obstructive pulmonary disease (COPD) according to age, gender, and residence in Greenland and to investigate the associated quality of care. The study was performed as an observational cross-sectional study using data on patients diagnosed with COPD, extracted from the electronical medical record (EMR) in Greenland. The total prevalence of patients aged 20-79 years diagnosed with COPD in Greenland in 2022 was 2.2%. The prevalence was significantly higher in the capital Nuuk compared to the remaining parts of Greenland (2.4% vs. 2.0%, respectively). Significantly more women than men were diagnosed with COPD, but the lung function of men was found to be significantly reduced/impaired compared to women. The prevalence of patients aged 40 years or above was 3.8%. The quality of care was significantly higher among patients living in Nuuk compared to the remaining parts of Greenland for eight out of ten quality indicators. The prevalence of COPD in Greenland is lower than in other comparable populations and might be underestimated. Continued focus on early detection of new cases and initiatives to improve and expand monitoring of quality-of-care measurements, including both additional clinical and patient reported outcomes, are recommended.

Low prevalence of diagnosed asthma in Greenland - a call for increased focus on diagnosing.

The aim of this study was to estimate prevalence of patients with asthma in Greenland according to age, gender and residence and to investigate the associated quality of care. The study was performed as a cross-sectional study with data extracted from the Greenlandic electronical medical record. A total of 870 patients aged 12 years or above were diagnosed with asthma at the end of 2022, corresponding to a prevalence of 1.9%. In 2020, the total prevalence was 0.2%. The prevalence of patients aged 12 years or above with asthma was highest among patients in Nuuk (3.3%) compared with patients in the remaining parts of Greenland (1.1%). More women than men were diagnosed with asthma, and the prevalence increased with age from 20 to 59 years. The prevalence of current smokers was high among the asthma population. The quality of care was significantly higher among patients living in Nuuk for all process indicators compared with patients from the remaining parts of Greenland. The prevalence of asthma in Greenland is low compared to other comparable populations and might be underestimated. Initiatives supporting increased focus on diagnosing asthma are thus warranted.

The impact of phenylalanine levels during pregnancy on birth weight and later development in children born to women with phenylketonuria.

Strict metabolic control with dietary treatment during pregnancy is essential for women with phenylketonuria (PKU), as elevated levels of phenylalanine (Phe) are toxic to the developing fetus. Maternal delay in achievement of the recommended Phe level during pregnancy is associated with delayed development of the child. However, the extent to which risk is changed by later or less stringently performed dietary treatment is unclear. The aim of this study was to investigate the impact of Phe levels and time of initiation of a Phe-restricted diet in pregnant women with PKU on birth weight, head circumference and later development of their children. Birth data were obtained from the medical records of women with PKU giving birth in the period 1980-2020. Later development was investigated by interviewing the mothers about their children's development and health. We included 79 children of 41 women with PKU. The women showed good adherence with the diet and had mean blood Phe levels within target range (248 ± 62 µmol/L). The children's development was not affected by fluctuations in the women's Phe levels, that occurred especially in first trimester. Despite maternal Phe levels being within target range, 19 children (26.8%) had low birth weight below 10th percentile. This study indicates that with dietary treatment, the children are born with the same prospect for normal development and health as children born to non-PKU mothers. This is despite maternal fluctuations in the Phe levels during first trimester.

Prevalence of patients using antihypertensive medication in Greenland, and an assessment of the importance of diagnosis for the associated quality of care - a cross-sectional study.

This study aimed to estimate the age- and sex specific prevalence of patients using antihypertensive medication in Greenland, and compared the quality of care between patients with and without a diagnosis for hypertension. The study was a cross-sectional study comparing patients using antihypertensive medication in 2020 (6,629 patients) and 2021 (7,008 patients), respectively. For data from 2021, patients with a medical diagnosis code were identified. Data was obtained from the Greenlandic electronic medical record. The population of Greenland was used as background population. Quality of care was evaluated based on suggested indicators by international guidelines and goals from Steno Diabetes Centre Greenland. The prevalence of patients aged ≥20 years using antihypertensive medication had increased from 16.7% in 2020 to 17.5% in 2021. The prevalence increased by age and was higher among women compared to men. In 2021, the prevalence of patients aged ≥20 years with a medical diagnosis code for hypertension was 7.9%. The use of antihypertensive medication in Greenland is common. The associated quality of care was low. However, process indicators were significantly improved when patients had a medical diagnosis code. Future focus must be on initiating initiatives ensuring that more patients are registered with a medical diagnosis code.

Intraabdominal and retroperitoneal soft-tissue sarcomas - Surgical treatment and outcomes.

BACKGROUND: Intraabdominal and retroperitoneal sarcomas (IaRS) are malignant connective tissue tumors. Surgical resection is often the only curative treatment. The primary objective was to report the mid-term outcomes following contemporary treatment protocols and identify prognostic factors. METHODS: A retrospective review of consecutive patients (n = 107) with IaRS treated at single center from 2013 until 2018 was conducted. Histological diagnosis, tumor grade, perioperative complications, mortality, and long-time survival were registered and retrieved from patient records. Primary and recurrent tumors were analyzed separately. RESULTS: A total of 107 patients were identified. Median follow-up time was 3.5 years. Thirty-day mortality was 3.4% and 90-day mortality was 5.6% for all tumors. The major complication rate was 18%. The 5-year estimated survival for primary and recurrent tumors was 55.4% and 48.4%, respectively. Multifocal disease was evident in 32% of the patient cohort, and 58% of patients in the recurrent group. Multivariate analysis for survival revealed a hazard ratio (HR) of 3.1 (95% CI 1.68-8.41) for multifocality, HR 2.9 (95% CI 1.28-6.98) for Clavien-Dindo grade, HR 2.3 (95% CI 1.21-4.31) for tumor grades 2 or 3, and HR 1.002 (95% CI 1.001-1.004) for surgical margins. CONCLUSIONS: Our study found overall acceptable morbidity and mortality, and identified prognostic markers for overall survival. Recurrent tumors were not associated with worse survival. Multifocality is associated with a worse overall survival. The prognostic factors identified were; tumor grade, multifocality, intralesional margins and postoperative complications.

Linoleic acid in adipose tissue and the risk of myocardial infarction: a case-cohort study.

PURPOSE: We investigated risk of myocardial infarction (MI) associated with the content of linoleic acid (LA) in adipose tissue, a biomarker of long-term dietary intake of LA and a marker of endogenous LA exposure. METHODS: Between 1993 and 1997, 57,053 middle-aged subjects were included in the Danish Diet, Cancer and Health cohort. We performed a case-cohort study that included a random sample of the full cohort (n = 3167) and all incident MI cases appearing during 16 years of follow-up (n = 2819). Information on incident MI cases was obtained by linkage with Danish nationwide registries. Adipose tissue biopsies were taken from the buttocks of the participants, and their fatty acid composition was determined using gas chromatography. HRs (hazard ratios) with 95% confidence intervals (CIs) were used to describe the associations between content of LA in adipose tissue and the risk of MI. HRs were calculated using weighted Cox proportional hazards regression with robust variance. RESULTS: After adjustment for established risk factors of MI, adipose tissue content of LA was not associated with the risk of MI in men and women combined (quintiles 5 versus 1, HR, 1.03 (95% CI, 0.85-1.25), P-trend = 0.970) or in men and women separately (quintiles 5 versus 1, HR, 1.05 (95% CI, 0.83-1.33), P-trend = 0.871 and quintiles 5 versus 1, HR, 0.99 (95% CI 0.72-1.37), P-trend = 0.928, respectively). Investigating the association between LA and MI with a shorter, 5- or 10-year duration of follow-up provided similar results. CONCLUSION: Content of LA in adipose tissue was not associated with the risk of MI.

Structural Basis for Toxin Inhibition in the VapXD Toxin-Antitoxin System.

Bacterial type II toxin-antitoxin (TA) modules encode a toxic protein that downregulates metabolism and a specific antitoxin that binds and inhibits the toxin during normal growth. In non-typeable Haemophilus influenzae, a common cause of infections in humans, the vapXD locus was found to constitute a functional TA module and contribute to pathogenicity; however, the mode of action of VapD and the mechanism of inhibition by the VapX antitoxin remain unknown. Here, we report the structure of the intact H. influenzae VapXD complex, revealing an unusual 2:1 TA molecular stoichiometry where a Cas2-like homodimer of VapD binds a single VapX antitoxin. VapX consists of an oligonucleotide/oligosaccharide-binding domain that docks into an asymmetrical cavity on the toxin dimer. Structures of isolated VapD further reveal how a symmetrical toxin homodimer adapts to interacting with an asymmetrical antitoxin and suggest how a primordial TA system evolved to become part of CRISPR-Cas immunity systems.

Small temperature differences can improve the performance of mesophilic sludge-based digesters.

OBJECTIVE: To assess the effect of small temperature increases in mesophilic sludge-based digesters in order to develop and evaluate strategies for improving the biogas production in full-scale digesters. RESULTS: Methane production was strongly affected by small temperature differences, and this result was consistent across samples from 15 full-scale digesters. The specific methane yield varied between 42 and 97.5 ml g VS-1 after 15 days of incubation at 35 °C, and improved when increasing the digester temperature to 39 °C. Only a limited quantity of additional gas was required to balance out the cost of heating and a positive energy balance was obtained. Further increases in temperature, in some cases, negatively affected the production when operated at 42 °C compared to 39 °C. CONCLUSIONS: Small temperature increases should be applied to mesophilic sludge-based digesters to optimize the biogas production and is applicable to digesters operated in the lower mesophilic temperature range.

Structural analysis of ribosomal RACK1 and its role in translational control.

Receptor for Activated C-Kinase 1 (RACK1) belongs to the WD40 family of proteins, known to act as scaffolding proteins in interaction networks. Accordingly, RACK1 is found to have numerous interacting partners ranging from kinases and signaling proteins to membrane bound receptors and ion channels. Interestingly, RACK1 has also been identified as a ribosomal protein present in all eukaryotic ribosomes. Structures of eukaryotic ribosomes have shown RACK1 to be located at the back of the head of the small ribosomal subunit. This suggests that RACK1 could act as a ribosomal scaffolding protein recruiting regulators of translation to the ribosome, and several studies have in fact found RACK1 to play a role in regulation of translation. To fully understand the role of RACK1 we need to understand whether the many reported interaction partners of RACK1 bind to free or ribosomal RACK1. In this review we provide a structural analysis of ribosome-bound RACK1 to provide a basis for answering this fundamental question. Our analysis shows that RACK1 is tightly bound to the ribosome through highly conserved and specific interactions confirming RACK1 as an integral ribosomal protein. Furthermore, we have analyzed whether reported binding sites for RACK1 interacting partners with a proposed role in translational control are accessible on ribosomal RACK1. Our analysis shows that most of the interaction partners with putative regulatory functions have binding sites that are available on ribosomal RACK1, supporting the role of RACK1 as a ribosomal signaling hub. We also discuss the possible role for RACK1 in recruitment of ribosomes to focal adhesion sites and regulation of local translation during cell spreading and migration.

Human Serum Metabolites Associate With Severity and Patient Outcomes in Traumatic Brain Injury.

Traumatic brain injury (TBI) is a major cause of death and disability worldwide, especially in children and young adults. TBI is an example of a medical condition where there are still major lacks in diagnostics and outcome prediction. Here we apply comprehensive metabolic profiling of serum samples from TBI patients and controls in two independent cohorts. The discovery study included 144 TBI patients, with the samples taken at the time of hospitalization. The patients were diagnosed as severe (sTBI; n=22), moderate (moTBI; n=14) or mild TBI (mTBI; n=108) according to Glasgow Coma Scale. The control group (n=28) comprised of acute orthopedic non-brain injuries. The validation study included sTBI (n=23), moTBI (n=7), mTBI (n=37) patients and controls (n=27). We show that two medium-chain fatty acids (decanoic and octanoic acids) and sugar derivatives including 2,3-bisphosphoglyceric acid are strongly associated with severity of TBI, and most of them are also detected at high concentrations in brain microdialysates of TBI patients. Based on metabolite concentrations from TBI patients at the time of hospitalization, an algorithm was developed that accurately predicted the patient outcomes (AUC=0.84 in validation cohort). Addition of the metabolites to the established clinical model (CRASH), comprising clinical and computed tomography data, significantly improved prediction of patient outcomes. The identified 'TBI metabotype' in serum, that may be indicative of disrupted blood-brain barrier, of protective physiological response and altered metabolism due to head trauma, offers a new avenue for the development of diagnostic and prognostic markers of broad spectrum of TBIs.

Air Medical Evacuations From the German North Sea Wind Farm Bard Offshore 1: Traumatic Injuries, Acute Diseases, and Rescue Process Times (2011-2013).

OBJECTIVE: Our purpose was 2-fold: 1) to show emergency-related traumatic injury and acute disease patterns and 2) to evaluate air rescue process times in a remotely located German offshore wind farm. Optimally, this will support methodologies to reduce offshore help time (time from the incoming emergency call until offshore arrival of the helicopter). METHODS: The type and severity of traumatic injuries and acute diseases were retrospectively analyzed for 39 air medevacs from August 2011 to December 2013, and the process times of air rescue missions were evaluated in detail. RESULTS: Forty-nine percent of the medevacs were related to traumatic injuries, whereas 41% were associated with acute diseases and 10% remained unclear. Cardiovascular and gastrointestinal disorders accounted for 90% of internal medical cases. About 69% of the trauma was related to contusions, lacerations, and cuts. The main body regions injured were limbs (∼59%) and head (∼32%). The total rescue time until arrival at the destination facility averaged 175.3 minutes (standard deviation = 54.4 minutes). The mean helicopter offshore arrival time was 106.9 minutes (standard deviation = 57.4 minutes) after the incoming emergency call. In 64% of the medevacs, the helicopter arrived on scene within a help time of 90 minutes. CONCLUSION: A reduction of help time (≤ 60 minutes) for time-critical severe trauma and acute diseases may be anticipated through rapid and focused medical and logistic decision-making processes by the onshore dispatch center combined with professional, qualified, and well-trained flight and rescue personnel.

Nano-Self-Assemblies Based on Synthetic Analogues of Mycobacterial Monomycoloyl Glycerol and DDA: Supramolecular Structure and Adjuvant Efficacy.

The mycobacterial cell-wall lipid monomycoloyl glycerol (MMG) is a potent immunostimulator, and cationic liposomes composed of a shorter synthetic analogue (MMG-1) and dimethyldioctadecylammonium (DDA) bromide represent a promising adjuvant that induces strong antigen-specific Th1 and Th17 responses. In the present study, we investigated the supramolecular structure and in vivo adjuvant activity of dispersions based on binary mixtures of DDA and an array of synthetic MMG-1 analogues (MMG-2/3/5/6) displaying longer (MMG-2) or shorter (MMG-3) alkyl chain lengths, or variations in stereochemistry of the polar headgroup (MMG-5) or of the hydrophobic moiety (MMG-6). Synchrotron small-angle X-ray scattering experiments and cryo transmission electron microscopy revealed that DDA:MMG-1/2/5/6 dispersions consisted of unilamellar and multilamellar vesicles (ULVs/MLVs), whereas a coexistence of both ULVs and hexosomes was observed for DDA:MMG-3, depending on the DDA:MMG molar ratio. The studies also showed that ULVs were formed, regardless of the structural characteristics of the neat MMG analogues in excess buffer [lamellar (MMG-1/2/5) or inverse hexagonal (MMG-3/6) phases]. Immunization of mice with a chlamydia antigen surface-adsorbed to DDA:MMG-1/3/6 dispersions revealed that all tested adjuvants were immunoactive and induced strong Th1 and Th17 responses with a potential for a central effector memory profile. The MMG-1 and MMG-6 analogues were equally immunoactive in vivo upon incorporation into DDA liposomes, despite the reported highly different immunostimulatory properties of the neat analogues in vitro, which were attributed to the different nanostructural characteristics. This clearly demonstrates that optimal formulation and delivery of MMG analogues to the immune system is of major importance and challenges the use of in vitro screening assays with nondispersed compounds to identify potential new vaccine adjuvants.

Structure of TSA2 reveals novel features of the active-site loop of peroxiredoxins.

Saccharomyces cerevisiae TSA2 belongs to the family of typical 2-Cys peroxiredoxins, a ubiquitously expressed family of redox-active enzymes that utilize a conserved peroxidatic cysteine to reduce peroxides. Typical 2-Cys peroxiredoxins have been shown to be involved in protection against oxidative stress and in hydrogen peroxide signalling. Furthermore, several 2-Cys peroxiredoxins, including S. cerevisiae TSA1 and TSA2, are able to switch to chaperone activity upon hyperoxidation of their peroxidatic cysteine. This makes the sensitivity to hyperoxidation of the peroxidatic cysteine a very important determinant for the cellular function of a peroxiredoxin under different cellular conditions. Typical 2-Cys peroxiredoxins exist as dimers, and in the course of the reaction the peroxidatic cysteine forms a disulfide with a resolving cysteine located in the C-terminus of its dimeric partner. This requires a local unfolding of the active site and the C-terminus. The balance between the fully folded and locally unfolded conformations is of key importance for the reactivity and sensitivity to hyperoxidation of the different peroxiredoxins. Here, the structure of a C48S mutant of TSA2 from S. cerevisiae that mimics the reduced state of the peroxidatic cysteine has been determined. The structure reveals a novel conformation for the strictly conserved Pro41, which is likely to affect the delicate balance between the fully folded and locally unfolded conformations of the active site, and therefore the reactivity and the sensitivity to hyperoxidation. Furthermore, the structure also explains the observed difference in the pKa values of the peroxidatic cysteines of S. cerevisiae TSA1 and TSA2 despite their very high sequence identity.

PGC-1α promotes exercise-induced autophagy in mouse skeletal muscle.

Recent evidence suggests that exercise stimulates the degradation of cellular components in skeletal muscle through activation of autophagy, but the time course of the autophagy response during recovery from exercise has not been determined. Furthermore, the regulatory mechanisms behind exercise-induced autophagy remain unclear, although the muscle oxidative phenotype has been linked with basal autophagy levels. Therefore, the aim of this study was to investigate the role of the key regulator of muscle oxidative capacity, PGC-1α, in exercise-induced autophagy at several time points during recovery. Mice with transgenic muscle-specific overexpression (TG) or knockout (MKO) of PGC-1α and their respective littermate controls were subjected to a single 1 h bout of treadmill running and euthanized immediately (0 h), 2, 6, and 10 h after exercise. In the PGC-1α MKO strain, quadriceps protein content of the autophagy marker LC3II was increased from 2 h into recovery in lox/lox control, but not in MKO mice. In the PGC-1α TG strain, quadriceps protein content of LC3II was increased from 2 h after exercise in TG, but not in WT. Although AMPK and ACC phosphorylation was increased immediately following exercise, the observed exercise-induced autophagy response was not associated with phosphorylation of the AMPK-target ULK1. However, lower protein carbonyl content was observed in lox/lox and TG mice after exercise coinciding with the increased LC3 lipidation. In conclusion, the present results suggest a role of skeletal muscle PGC-1α in coordinating several exercise-induced adaptive responses including autophagic removal of damaged cellular components.