Extracellular vesicle characteristics and micro RNA content in cerebral palsy and typically developed individuals at rest and in response to aerobic exercise.

In this study, the properties of circulating extracellular vesicles (EVs) were examined in cerebral palsy (CP) and typically developed (TD) individuals at rest and after aerobic exercise, focusing on the size, concentration, and microRNA cargo of EVs. Nine adult individuals with CP performed a single exercise bout consisting of 45 min of Frame Running, and TD participants completed either 45 min of cycling (n = 10; TD EX) or were enrolled as controls with no exercise (n = 10; TD CON). Blood was drawn before and 30 min after exercise and analyzed for EV concentration, size, and microRNA content. The size of EVs was similar in CP vs. TD, and exercise had no effect. Individuals with CP had an overall lower concentration (~25%, p \u3c 0.05) of EVs. At baseline, let-7a, let-7b and let-7e were downregulated in individuals with CP compared to TD (p \u3c 0.05), while miR-100 expression was higher, and miR-877 and miR-4433 lower in CP compared to TD after exercise (p \u3c 0.05). Interestingly, miR-486 was upregulated ~2-fold in the EVs of CP vs. TD both at baseline and after exercise. We then performed an in silico analysis of miR-486 targets and identified the satellite cell stemness factor Pax7 as a target of miR-486. C2C12 myoblasts were cultured with a miR-486 mimetic and RNA-sequencing was performed. Gene enrichment analysis revealed that several genes involved in sarcomerogenesis and extracellular matrix (ECM) were downregulated. Our data suggest that circulating miR-486 transported by EVs is elevated in individuals with CP and that miR-486 alters the transcriptome of myoblasts affecting both ECM- and sarcomerogenesis-related genes, providing a link to the skeletal muscle alterations observed in individuals with C

Exceptional Larval Morphology of Nine Species of the Anastrepha mucronota Species Group (Diptera: Tephritidae)

Anastrepha is the most diverse and economically important genus of Tephritidae in the American tropics and subtropics. The striking morphology of the third instars of Anastrepha caballeroi Norrbom, Anastrepha crebra Stone, Anastrepha haplacantha Norrbom & Korytkowski, Anastrepha korytkowskii Norrbom, Anastrepha nolazcoae Norrbom & Korytkowski, and three newly discovered and as yet formally unnamed species (Anastrepha sp. Peru-82, Anastrepha sp. nr. protuberans, and Anastrepha sp. Sur-16), and the more typical morphology of Anastrepha aphelocentema Stone, are described using light and scanning electron microscopy. To contribute to a better understanding of the interspecific and intraspecific variation among species in the mucronota species group and facilitate phylogenetic studies, we integrate molecular and morphological techniques to confirm the identity and describe third instars. Larva-adult associations and the identification of described larvae were confirmed using DNA barcodes. We provide diagnostic characters to distinguish larvae among these nine species of the mucronota group and separate them from those of the 29 other Anastrepha species previously described. We introduce the vertical comb-like processes on the oral margin as a novel character, and the unusual character states, including position and shape of the preoral lobe, and dentate or fringed posterior margins of the oral ridges and accessory plates. Our comparative morphology concurs with most previously inferred phylogenetic relationships within the mucronota group

Humanin skeletal muscle protein levels increase after resistance training in men with impaired glucose metabolism

Humanin (HN) is a mitochondrially encoded and secreted peptide linked to glucose metabolism and tissue protecting mechanisms. Whether skeletal muscle HN gene or protein expression is influenced by exercise remains unknown. In this intervention study we show, for the first time, that HN protein levels increase in human skeletal muscle following 12 weeks of resistance training in persons with prediabetes. Male subjects (n = 55) with impaired glucose regulation (IGR) were recruited and randomly assigned to resistance training, Nordic walking or a control group. The exercise interventions were performed three times per week for 12 weeks with progressively increased intensity during the intervention period. Biopsies from the vastus lateralis muscle and venous blood samples were taken before and after the intervention. Skeletal muscle and serum protein levels of HN were analyzed as well as skeletal muscle gene expression of the mitochondrially encoded gene MT-RNR2, containing the open reading frame for HN. To elucidate mitochondrial training adaptation, mtDNA, and nuclear DNA as well as Citrate synthase were measured. Skeletal muscle HN protein levels increased by 35% after 12 weeks of resistance training. No change in humanin protein levels was seen in serum in any of the intervention groups. There was a significant correlation between humanin levels in serum and the improvements in the 2 h glucose loading test in the resistance training group. The increase in HN protein levels in skeletal muscle after regular resistance training in prediabetic males may suggest a role for HN in the regulation of glucose metabolism. Given the preventative effect of exercise on diabetes type 2, the role of HN as a mitochondrially derived peptide and an exercise-responsive mitokine warrants further investigation.</p

Exercise and regulation of mitochondrial biogenesis factors in human skeletal muscle

Regular physical activity has many positive implications on health and performance, such as lowered risk for premature death, improved glucose metabolism and cardiovascular function as well as endurance capacity. Even a single bout of exercise is enough stimulus to change expression of many skeletal muscle genes. When exercise is performed regularly, the added effects of many bouts lead to changes of muscle phenotype. One of the most profound changes in skeletal muscle is an increased mitochondrial density. This contributes to an improved oxidative capacity, enhanced aerobic and endurance performance as well as to the positive health effects associated with regular endurance training. The exercise-induced skeletal muscle adaptations have been suggested to be influenced by many stimuli, e.g. changes in calcium concentration, metabolic alterations and oxygen tension. The understanding of the regulatory pathways in vivo, especially in humans, is largely lacking. This thesis aimed to further explore the exercise-regulation of selected mitochondrial biogenesis factors in human skeletal muscle. The influence of a single bout of exercise, endurance training and activity level on the co-activators PGC-1alpha and -1beta and the mitochondrial transcription factors TFAM, TFB1M and TFB2M was studied. Additional aims were to explore the relative importance of signaling pathways suggested to regulate PGC-1 in exercising skeletal muscle and the role of enhanced metabolic perturbation. A one-legged knee extension model was used where blood flow is restricted and metabolic perturbation induced in a controlled fashion. Also, a comparison was made between elite athletes, moderately active and spinal cord injured. A single bout of exercise with enhanced metabolic perturbation induced both PGC-1alpha mRNA expression and AMPK activation (phosphorylation) more than exercise with normal blood flow. Even though the calcineurin and p38 signaling pathways were activated with exercise, there was no difference in the increase between exercise conditions why they do not seem to have dominant roles in the regulation of exercise-induced PGC-1alpha expression. PGC-1beta mRNA increased with normal blood flow exercise, suggesting differential regulation of the two coactivators. TFAM protein, but not mRNA, levels were increased after 4 weeks of endurance training. Also, elite athletes had a higher TFAM protein level compared to moderately active. TFB1M and TFB2M mRNA, but not protein, levels were higher in elite athletes than in moderately active, and increased with endurance training in the leg that exercised with restricted blood flow. It is concluded that exercise transcriptionally activates PGC-1alpha and -1beta but their regulation seems to be different. It is indicated that AMPK has a greater influence on exercise-induced PGC-1alpha mRNA compared to calcineurin and p38. The involvement of TFAM in exercise-induced mitochondrial biogenesis is supported and TFAM is most likely regulated through protein stabilization. Conversely, pre-translational changes occur for the TFB factors. Exercise-induced expression of PGC-1alpha most likely contributes to the increase in TFAM protein which in turn drives mitochondrial biogenesis. In the future, studies are needed to better establish the regulatory links between PGC-1alpha and mitochondrial regulatory factors, and to evaluate the temporal patterns between these factors. Such knowledge would further explain how exercise leads to mitochondrial biogenesis

Modelling in vivo creatine/phosphocreatine in vitro reveals divergent adaptations in human muscle mitochondrial respiratory control by ADP after acute and chronic exercise

International audienceMitochondrial respiratory control by ADP (Kmapp) is viewed as a critical regulator of muscle energy homeostasis. However, acute exercise increases, decreases or has no effect on Kmapp in human muscle, whereas chronic exercise surprisingly decreases sensitivity despite greater mitochondrial content. We hypothesized that modelling in vivo mitochondrial creatine kinase (mtCK)‐dependent phosphate‐shuttling conditions in vitro would reveal increased sensitivity (lower Kmapp) after acute and chronic exercise. The Kmapp was determined in vitro with 20 mm Cr (+Cr), 0 mm Cr (−Cr) or ‘in vivo exercising’ 20 mm Cr/2.4 mm PCr (Cr:PCr) on vastus lateralis biopsies sampled from 11 men before, immediately after and 3 h after exercise on the first, fifth and ninth sessions over 3 weeks. Dynamic responses to acute exercise occurred throughout training, whereby the first session did not change Kmapp with in vivo Cr:PCr despite increases in −Cr. The fifth session decreased sensitivity with Cr:PCr or +Cr despite no change in −Cr. Chronic exercise increased sensitivity ±Cr in association with increased electron transport chain content (+33–62% complexes I–V), supporting classic proposals that link increased sensitivity to oxidative capacity. However, in vivo Cr:PCr reveals a perplexing decreased sensitivity, contrasting the increases seen ±Cr. Functional responses occurred without changes in fibre type or proteins regulating mitochondrial–cytosolic energy exchange (mtCK, VDAC and ANT). Despite the dynamic responses seen with ±Cr, modelling in vivo phosphate‐shuttling conditions in vitro reveals that ADP sensitivity is unchanged after high‐intensity exercise and is decreased after training. These findings challenge our understanding of how exercise regulates skeletal muscle energy homeostasis

Expression profiling following local muscle inactivity in humans provides new perspective on diabetes-related genes

Physical activity enhances muscle mitochondrial gene expression, while inactivity and mitochondrial dysfunction are both risk factors for developing diabetes. Defective activation of the transcriptional coactivator PGC-1α may contribute to the gene expression pattern observed in diabetic and insulin-resistant skeletal muscle. We proposed that greater insight into the mitochondrial component of skeletal muscle “diabetes” would be possible if the clinical transcriptome data were contrasted with local muscle inactivity-induced modulation of mitochondrial genes in otherwise healthy subjects. We studied PPARGC1A (PGC-1α), PPARGC1B (PGC-1β), NRF1, and a variety of mitochondrial DNA (mtDNA) and nuclear-encoded mitochondrial genes critical for oxidative phosphorylation in soleus muscle biopsies obtained from six healthy men and women before and after 5 weeks of local muscle inactivity. Muscle inactivity resulted in a coordinated down-regulation of PGC-1α and genes involved with mitochondrial metabolism, including muscle substrate delivery genes. Decreased expression of the mtDNA helicase Twinkle was related to the decline in mitochondrial RNA polymerase ( r = 0.83, p < 0.04), suggesting that mtDNA transcription and replication are coregulated in human muscle tissue. In contrast to the situation in diabetes, PGC-1β expression was not significantly altered, while NRF1 expression was actually up-regulated following muscle inactivity. We can conclude that reduced PGC-1α expression described in Type 2 diabetes may be partly explained by muscle inactivity. Further, although diabetes patients are typically inactive, our analysis indicates that local muscle inactivity may not be expected to contribute to the decreased NRF1 and PGC-1β expression noted in insulin-resistant and Type 2 diabetes patients, suggesting these changes may be more disease specific

Extracellular vesicle characteristics and microRNA content in cerebral palsy and typically developed individuals at rest and in response to aerobic exercise

In this study, the properties of circulating extracellular vesicles (EVs) were examined in cerebral palsy (CP) and typically developed (TD) individuals at rest and after aerobic exercise, focusing on the size, concentration, and microRNA cargo of EVs. Nine adult individuals with CP performed a single exercise bout consisting of 45 min of Frame Running, and TD participants completed either 45 min of cycling (n = 10; TD EX) or were enrolled as controls with no exercise (n = 10; TD CON). Blood was drawn before and 30 min after exercise and analyzed for EV concentration, size, and microRNA content. The size of EVs was similar in CP vs. TD, and exercise had no effect. Individuals with CP had an overall lower concentration (similar to 25%, p &amp;lt; 0.05) of EVs. At baseline, let-7a, let-7b and let-7e were downregulated in individuals with CP compared to TD (p &amp;lt; 0.05), while miR-100 expression was higher, and miR-877 and miR-4433 lower in CP compared to TD after exercise (p &amp;lt; 0.05). Interestingly, miR-486 was upregulated similar to 2-fold in the EVs of CP vs. TD both at baseline and after exercise. We then performed an in silico analysis of miR-486 targets and identified the satellite cell stemness factor Pax7 as a target of miR-486. C2C12 myoblasts were cultured with a miR-486 mimetic and RNA-sequencing was performed. Gene enrichment analysis revealed that several genes involved in sarcomerogenesis and extracellular matrix (ECM) were downregulated. Our data suggest that circulating miR-486 transported by EVs is elevated in individuals with CP and that miR-486 alters the transcriptome of myoblasts affecting both ECM- and sarcomerogenesis-related genes, providing a link to the skeletal muscle alterations observed in individuals with CP.Funding Agencies|Futurum-the Academy for Health and Care, Region Jonkoping County, Sweden; Swedish Kidney Foundation [FUTURUM-937508, 870471]; NIH [F2019-0048]; H.K.H. Kronprinsessan Lovisas foerening foer barnasjukvard [P20GM104320-07]; Swedish Society of Medical Research; Sunnerdahls handikappstiftelse; Norrbacka Eugenia Stiftelsen; career grant from the Swedish National Space Agency; [2021-00159]</p