Increased serum visfatin level is associated with fat deposition of the lumbar spine in ankylosing spondylitis patients.

Objectives: To assess the serum visfatin levels in patients with ankylosing spondylitis (AS), as well as its correlation with fat deposition of the lumbar spine. Methods: Serum visfatin levels were detected by enzyme-linked immunosorbent assay (ELISA) in 50 AS patients and 75 sex-and age-matched healthy controls. The clinical and laboratory indexes of AS patients were recorded, and the lumbar spine magnetic resonance scan was performed to evaluate the lumbar spine fat deposition in AS patients. The level of serum visfatin and its correlation with lumbar fat deposition were analyzed, and the risk factors of AS lumbar MRI fat deposition were evaluated by Logistic regression. Results: Serum visfatin levels in AS patients were elevated compared with that in healthy controls (p < 0.001), and were more significant in patients with fat deposition and syndesmophyte formation (p = 0.017 and p = 0.014, respectively). Serum visfatin levels were positively correlated with CRP, BASDAI, mSASSS and fat deposition (all p < 0.05). Age (OR = 1.085, 95% CI: 1.005-1.173, p = 0.038), disease duration (OR = 1.267, 95% CI: 1.017-1.578, p = 0.035), and visfatin (OR = 1.846, 95% CI: 1.004-3.393, p = 0.048) were risk factors for fat deposition in AS patients. Conclusions: The level of serum visfatin in AS patients is significantly increased, which is associated with fat deposition on lumbar MRI. Elevated visfatin level is an independent risk factor for AS lumbar fat deposition.

Antibiotics and microplastics in manure and surrounding soil of farms in the Loess Plateau: Occurrence and correlation.

The wide use of animal manure in farmland operations is a source of soil nutrients. However, the return of manure affected antibiotics and microplastics in the soil, thus the potential ecological risks cannot be overlooked. This study investigated the distribution of different antibiotics and microplastics and their correlation. It was found that multiple classes of veterinary antibiotics and microplastics could be detected simultaneously in most manure and soil. In manure, the average concentration of tetracycline antibiotics was higher than fluoroquinolones and sulfonamides. A much lower concentration of antibiotics was found in the soil samples relative to manure. The abundance of microplastics ranged from 21,333 to 88,333 n/kg in manure, and the average abundance was 50,583 ± 24,318 n/kg. The average abundance was 3056 ± 1746 n/kg in the soil. It confirmed that applying organic fertilizer to agricultural soil and the application of plastic mulch in farmlands introduced microplastics. Moreover, microplastics were found to be significantly correlated with antibiotics (r = 0.698, p < 0.001). The correlation between microplastics and antibiotics in soil was significantly weaker than that in manure. Farms could be the hotspot for the co-spread of microplastics and antibiotics. These findings highlighted the co-occurrence of antibiotics and microplastics in agricultural environments.

Synergistic Effects of Multiple Environmental Factors on Degradation of Silicone Rubber Seals under Marine Atmosphere.

In this research, the degradation behavior and failure mechanism of silicone rubber seal rings under the synergistic effects of multiple factors in the marine atmosphere are fully investigated. Firstly, four aging factors of air, temperature, compressive stress, and chemical medium were determined by analyzing the service environment profile of silicone rubber seal under a marine atmosphere environment. Secondly, to better simulate the actual service environment of silicone rubber and shorten the test period, an artificially accelerated aging test was designed and carried out in the laboratory. In this paper, temperature is utilized as the accelerating stress. According to the results of the pre-test, the accelerating stress level is finally determined to be 110-150 ∘C. In addition, the compression set applied is consistent with the constant compression permanent deformation value of 28% of the silicone rubber in the actual service process. Finally, through the macroscopic physical properties and microstructure analysis of the samples before and after aging, the corresponding test results are given, and the failure mechanism is analyzed and discussed in detail. Through the above test results and discussion, it can be concluded that the aging process of multi-factor coupling on the lower silicone rubber seal ring is uneven, and its aging process is not a simple superposition of multiple environmental factors. More importantly, the above test data and results are of great significance for evaluating the service life of silicone rubber seals, which can be utilized in the future to improve the reliability and durability of related equipment in the marine environment.

The effect of study-abroad experience on lexical translation among interpreting students.

This study investigates the impact of study-abroad experience (SAE) on lexical translation among 50 Chinese (L1)-English (L2) interpreting students. Participants were divided into two groups based on their experience abroad. Both groups consisted of 25 unbalanced L2 learners who were matched in age, working memory, length of interpreting training, and L2 proficiency. Bidirectional word translation recognition tasks, from L1 to L2 and L2 to L1, highlighted several key findings: (1) both groups were significantly more accurate and faster from L2 to L1 than in the reverse direction; (2) the study abroad (SA) group was more inclined to respond quickly at the risk of making errors, whereas the non-study abroad (NSA) group tended to be more cautious, prioritising accuracy over speed; (3) the SA group were more balanced and consistent in their performance across lexical translations in both directions than the NSA group. These results emphasise the potent effect of SAE in resolving bilinguals' language competition, especially in streamlining language switching, a cognitive process critical for interpreting students engaging daily with dual languages.

Effect of Aerobic Exercise in Chinese Adult Individuals at Risk for Type 2 Diabetes Mellitus (T2DM) with Low Salivary Amylase Gene (AMY1) Copy Number Variation.

Purpose: Type 2 Diabetes mellitus (T2DM) has become a life-threatening health problem around the world. Studies have confirmed that aerobic exercise can prevent the risk of T2DM. Furthermore, recent research showed that salivary amylase gene (AMY1) copy number variation (CNV) could be one of the genetic factors that increased the risk of T2DM. To provide more evidence on how AMY1 CNV and exercise is correlated with the risk of T2DM, we designed this study to show the differences in postprandial carbohydrate metabolism between people with different AMY1 copy numbers, and how aerobic exercise can influence this process. Participants and Methods: Sixteen participants without cardiovascular disease were chosen, 8 with AMY1 CNV≥6 (High CNV group, HCNV), and 8 with AMY1 CNV ≤ 2 (Low CNV group, LCNV). All participants were Chinese, Han nationality, 18 to 40 years old, with fasting blood glucose lower than 6.1 mmol/L and normal blood pressure levels. They were asked to visit the laboratory in fasting state and drink a cup of solution with 75 grams of edible carbohydrate (glucose or starch). After carbohydrate intake, blood samples were taken at certain times at rest or after aerobic exercise. Blood glucose levels were tested with a portable blood glucose monitor, and insulin levels were tested with the enzyme-linked immunosorbent assay (ELISA). Results: The LCNV group had significantly higher resting insulin levels and homeostatic model assessment of insulin resistance (HOMA-IR) than the HCNV group. Compared to the HCNV group, postprandial blood glucose levels and insulin levels were insensitive to starch intake in the LCNV group. However, this difference disappeared after aerobic exercise was added as an intervention. Conclusion: Lower AMY1 CNV could be associated with higher risk of T2DM and complex carbohydrate metabolism disorder, while aerobic exercise can reduce the risk by increasing the carbohydrate utilization rate.

Salivary amylase gene (AMY1) copy number variation has only a minor correlation with body composition in Chinese adults.

BACKGROUND: According to the WHO, about 39% of the global adult population were overweight or obese in 2016. Obesity has high heritability, with more than 1000 variants so far identified. There have been reports indicating that salivary amylase gene (AMY1) copy number was one of these variants, yet its association with obesity remains controversial. OBJECTIVE: Our research aimed to provide more evidence on the relationship of AMY1 copy number variation (CNV) with body mass index (BMI) and body composition. METHODS: We recruited 133 Chinese adults (65 males, 68 females, 18-25 years old) with normal fasting blood glucose and blood pressure levels. 19 males were selected for a 10-week intervention to change body composition. After anthropometric measurements, BMI was calculated, and body composition was measured using dual energy X-ray absorptiometry (DEXA). For the 19 selected participants, we collected their height, weight, and body composition data one more time after intervention. All participants were required to leave their saliva samples and their AMY1 copy number was determined by real-time fluorescence quantitative PCR. RESULTS: We failed to find any significant difference in BMI and body composition between different copy number groups. Only a weak correlation was found between body muscle mass and body fat mass. After adjusted for height and weight, AMY1 CNV explained 4.83% of the variance and one single increase in AMY1 CNV can increase 0.214 kg of the body muscle mass, while one single increase in AMY1 CNV can decrease 0.217 kg of the body fat mass and explained 4.69% of the variance. CONCLUSIONS: As a genetic factor, the AMY1 gene copy number variation has only a minor correlation with BMI and body composition, and its effect can easily be hidden by other factors such as individual diet and exercise habit.

Downhill running induced DNA damage enhances mitochondrial membrane permeability by facilitating ER-mitochondria signaling.

To observe whether downhill running can lead to DNA damage in skeletal muscle cells and changes in mitochondrial membrane permeability and to explore whether the DNA damage caused by downhill running can lead to changes in mitochondrial membrane permeability by regulating the components of the endoplasmic reticulum mitochondrial coupling structure (MAM). A total of 48 male adult Sprague-Dawley rats were randomly divided into a control group (C, n = 8) and a motor group (E, n = 40). Rats in Group E were further divided into 0 h (E0), 12 h (E12), 24 h (E24), 48 h (E48) and 72 h (E72) after prescribed exercise, with 8 rats in each group. At each time point, flounder muscle was collected under general anaesthesia. The DNA oxidative damage marker 8-hydroxydeoxyguanosine (8-OHdG) was detected by immunofluorescence. The expression levels of the DNA damage-related protein p53 in the nucleus and the EI24 protein and reep1 protein in whole cells were detected by Western blot. The colocalization coefficients of the endoplasmic reticulum protein EI24 and the mitochondrial protein Vdac2 were determined by immunofluorescence double staining, and the concentration of Ca2+ in skeletal muscle mitochondria was detected by a fluorescent probe. Finally, the opening of the mitochondrial membrane permeability transition pore (mPTP) was detected by immunofluorescence. Twelve hours after downhill running, the mitochondrial membrane permeability of the mPTP opened the most (P < 0.05), the content of 8-OHdG in skeletal muscle peaked (P < 0.05), and the levels of the regulatory protein p53, mitochondrial Ca2+, and the EI24 and reep1 proteins peaked (P < 0.01). Moreover, the colocalization coefficients of EI24 and Vdac2 and the Mandes coefficients of the two proteins increased first and then recovered 72 h after exercise (P < 0.05). (1) Downhill running can lead to DNA damage in skeletal muscle cells, overload of mitochondrial Ca2+ and large opening of membrane permeability transformation pores. (2) The DNA damage caused by downhill running may result in p53 promoting the transcriptional activation of reep1 and EI24, enhancing the interaction between EI24 and Vdac2, and then leading to an increase in Ca2+ in skeletal muscle mitochondria and the opening of membrane permeability transition pores.

Hypochlorous Acid-Activated Multifunctional Fluorescence Platform for Depression Therapy and Antidepressant Efficacy Evaluation.

Current diagnosis of depression rests on the symptoms, so it still lacks objective criteria. Meanwhile, existing treatment of depression is dominated by antidepressants, which produce troublesome side effects and usually require months to achieve effect. Therefore, more reliable diagnostic criteria and effective therapy are urgently needed. Some core hallmarks in the etiology of depression have been established, including declined neurotransmitters and inflammatory responses, manifesting in oxidative stress. Thus, we fabricated a HClO-triggered multifunctional fluorescence platform (MB-Rs) for simultaneous neurotransmitter/antidepressant delivery and efficacy evaluation. In MB-Rs, although a urea linkage could be specifically cut off by HClO, methylene blue (MB) endowed with excellent anti-inflammatory and optical properties was covalently linked with neurotransmitters (dopamine or 5-hydroxytryptamine) or antidepressants (fluoxetine). Encountering excess HClO in the brain of mice with depression, MB-Rs released corresponding antidepressants and MB with anti-inflammatory and bright fluorescence. By relieving oxidative stress, inflammation, and coinstantaneous increasing neurotransmitters, MB-Rs elicited better antidepressant response and fewer side effects compared with clinical antidepressants. Furthermore, MB-Rs successfully evaluated the efficacy of antidepressants in mice based on HClO-induced fluorescence. Therefore, this work provides a promising platform for depression diagnosis and treatment.

FAM134B-mediated ER-phagy alleviates endoplasmic reticulum stress of rat soleus muscle in response to acute exercise.

ER-phagy is a selective endoplasmic reticulum (ER) autophagy mediated by ER-localized receptors, which ensures proper cellular homeostasis under stress. However, it remains unclear whether ER-phagy is involved in skeletal muscle response to exercise stress. Male 8-week-old Sprague-Dawley rats were subjected to an exercise protocol comprising a 90-min downhill run with a slope of -16° and a speed of 16 m/min. The soleus of the rats was sampled at 0, 12, 24, 48, and 72 h after exercise. After exercise, the sarcoplasmic/ER calcium ATPase (SERCA) content decreased, the protein disulphide isomerase (PDI) content increased, and ER stress (GRP78 and CRT) and autophagy (FAM134B and LC3)-related protein expression increased in the soleus muscle of rats, and gradually recovered with time. We also used pharmacological methods to simulate the effects of exercise stress on skeletal muscle cells to further explore the mechanism of ER-phagy in skeletal muscle cells. Thapsigargin was used to inhibit the SERCA pump of L6 myoblasts and successfully induce ER stress and activate ER-phagy. During this process, the ER-phagy receptor FAM134B anchors and fragments ER, and then binds with LC3 to form autophagosomes. These results suggest that ER-phagy is involved in the skeletal muscle cell response to exercise stress, which helps to maintain cellular ER homeostasis during exercise.

[Effects of heavy-load exercise on skeletal muscle cells apoptosis and mechanisms of mitochondrial apoptosis in rats].

OBJECTIVE: To analyze the molecular mechanisms of skeletal muscle cells apoptosis induced by heavy-load exercise with Omi as the entry point. METHODS: One hundred and twenty-six adult SD rats were randomly divided into five groups: control group(C), eccentric exercise group (E), simple blocking group (U), DMSO group (D) and exercise block group (EU). In addition to the C group, the other four groups were randomly divided into 0 h after experiment, 12 h after experiment, 24 h after experiment, 48 h after experiment and 72 h after experiment with 6 rats in each group. E and EU group were submitted to a heavy-load exercise on a treadmill down a 16° decline, 16 m/min for 90 minutes. U, D and EU group were one-time intervened with drugs. U and EU groups were intraperitoneally injected with 1.5 µmol/kg ucf-101, D group were intraperitoneally injected with 1.5 µmoL/kg 0.5% DMSO. The rats were sacrificed in batches at different time points after experiment, then the soleus were saved to detect the Caspase-3,-8,-9,-12 activities and protein expressions of Omi and XIAP. RESULTS: Compared with group C, the mitochondrial distribution and morphology appeared the typical ultrastructure pathological changes, the opening degree of MPTP was increased significantly (P＜0.01) or (P＜0.05), protein expressions of Omi and XIAP were increased significantly (P＜0.01 or P＜0.05), the activities of Caspase-9 and Caspase-3 were increased significantly (P＜0.01 or P＜0.05) in group E. Compared with group C, there was no significant difference in XIAP protein and caspase-9, - 3 activities in group U and Group D. The change trend of XIAP protein and Caspase-9, - 3 activities was the same as those between EU group and E group, but the change range of XIAP protein in EU group was significantly higher than that in E group (P＜0.01), and the change ranges of caspase-9, - 3 activities in EU group were significantly lower than those in E group (P＜0.01). CONCLUSION: A single heavy-load exercise can induce changes in the mitochondria morphology and structure in rats, open the high permeability of MPTP, and improve the expression of Omi protein, then through its downstream XIAP-Caspase pathway, start the mitochondrial apoptosis pathway mediated by caspase-9, and finally lead to myocyte apoptosis. The inhibition of Omi can reduce the cell apoptosis level of motor induced skeletal muscle cells.

Effects of a Low-Carbohydrate High-Fat Diet Combined with High-Intensity Interval Training on Body Composition and Maximal Oxygen Uptake: A Systematic Review and Meta-Analysis.

The low-carbohydrate high-fat (LCHF) diet has recently been subject to attention on account of its reported influences on body composition and physical performance. However, the combined effect of LCHF with high-intensity interval training (HIIT) is unclear. A systematic review and meta-analysis were conducted to explore the effect of the LCHF diet combined with HIIT on human body composition (i.e., body weight (BM), body mass index (BMI), fat mass (FM), body fat percentage (BFP), fat-free mass (FFM)) and maximal oxygen uptake (VO2max). Online libraries (PubMed, Web of Science, EMBASE, Cochrane Library, EBSCO, CNKI, Wan Fang) were used to search initial studies until July 2021, from which 10 out of 2440 studies were included. WMD served as the effect size with a confidence interval value of 95%. The results of meta-analysis showed a significant reduction in BM (WMD = -5.299; 95% CI: -7.223, -3.376, p = 0.000), BMI (WMD = -1.150; 95% CI: -2.225, -0.075, p = 0.036), BFP (WMD = -2.787; 95% CI: -4.738, -0.835, p = 0.005) and a significant increase in VO2max (WMD = 3.311; 95% CI: 1.705, 4.918, p = 0.000), while FM (WMD = -2.221; 95% CI: -4.582, 0.139, p = 0.065) and FFM (WMD = 0.487; 95% CI: -3.512, 4.469, p = 0.814) remained unchanged. In conclusion, the LCHF diet combined with HIIT can reduce weight and fat effectively. This combination is sufficient to prevent muscle mass loss during LCHF, and further enhance VO2max. Further research might be required to clarify the effect of other types of exercise on body composition and physical performance during LCHF.

X-CNV: genome-wide prediction of the pathogenicity of copy number variations.

BACKGROUND: Gene copy number variations (CNVs) contribute to genetic diversity and disease prevalence across populations. Substantial efforts have been made to decipher the relationship between CNVs and pathogenesis but with limited success. RESULTS: We have developed a novel computational framework X-CNV ( www.unimd.org/XCNV ), to predict the pathogenicity of CNVs by integrating more than 30 informative features such as allele frequency (AF), CNV length, CNV type, and some deleterious scores. Notably, over 14 million CNVs across various ethnic groups, covering nearly 93% of the human genome, were unified to calculate the AF. X-CNV, which yielded area under curve (AUC) values of 0.96 and 0.94 in training and validation sets, was demonstrated to outperform other available tools in terms of CNV pathogenicity prediction. A meta-voting prediction (MVP) score was developed to quantitively measure the pathogenic effect, which is based on the probabilistic value generated from the XGBoost algorithm. The proposed MVP score demonstrated a high discriminative power in determining pathogenetic CNVs for inherited traits/diseases in different ethnic groups. CONCLUSIONS: The ability of the X-CNV framework to quantitatively prioritize functional, deleterious, and disease-causing CNV on a genome-wide basis outperformed current CNV-annotation tools and will have broad utility in population genetics, disease-association studies, and diagnostic screening.

Downhill Running Decreases the Acetylation of Tubulins and Impairs Autophagosome Degradation in Rat Skeletal Muscle.

PURPOSE: This study was designed to probe the effect of downhill running on microtubule acetylation and autophagic flux in rat skeletal muscle. METHODS: Sprague-Dawley rats were subjected to an exercise protocol of a 90-min downhill run with a slope of -16° and a speed of 16 m·min-1, and then the soleus was sampled at 0, 12, 24, 48, and 72 h after exercise. Protein expression levels of microtubule-associated protein 1 light chain 3 (LC3), p62/sequestosome 1 (p62), α-tubulin, and acetylated α-tubulin (AcK40 α-tubulin) were detected by Western blotting. Alpha-tubulin was costained with AcK40 α-tubulin or cytoplasmic dynein intermediate chain in a single muscle fiber, and LC3 was costained with lysosomal-associated membrane protein 1 in cryosections. To assess autophagic flux in vivo, colchicine or vehicle was injected intraperitoneally 3 d before the exercise experiment, and the protein levels of LC3 and p62 were measured by Western blotting. RESULTS: Downhill running induced a significant increase in the protein levels of LC3-II and p62, whereas the level and proportion of AcK40 α-tubulin were markedly decreased. Furthermore, the amount of dynein on α-tubulin was decreased after downhill running, and autophagosomes accumulated in the middle of myofibrils. Importantly, LC3-II flux was decreased after downhill running compared with that in the control group. CONCLUSIONS: A bout of downhill running decreases microtubule acetylation, which may impair dynein recruitment and autophagosome transportation, causing blocked autophagic flux.

[TGF-ß1/ERK/CTGF pathway involved in effect of acupuncture on exercise-induced skeletal muscle fibrosis].

OBJECTIVE: To observe the changes of the skeletal muscle fibrosis and changes of transforming growth factor-ß1(TGF-ß1)/ extracellular signal-regulated kinase (ERK) / connective tissue growth factor (CTGF)pathway in rats after long-term eccentric exercise and acupuncture intervention, so as to explore the mechanism of acupuncture in regulating exercise-induced skeletal muscle fibrosis. METHODS: A total of 30 male SD rats were randomly divided into normal control, exercise and acupuncture group, with 10 rats in each group. The rat model of skeletal muscle fibrosis was established by eccentric exercise for 3 weeks. After exercise trained every time, the rats of the acupuncture group received acupuncture stimulation by holding the acupuncture needle to obliquely and longitudinally penetrate the ventral part of triceps of the lower leg along its lateral side, followed by retaining the needle for 2 min. Changes of the collagen fibers in each group was observed by scanning electron microscope. The expressions of Collagen Ⅰ, TGF-ß1, phosphated (p)-ERK/ERK and CTGF proteins were detected by Western blot. RESULTS: After 3 weeks of eccentric exercise and acupuncture, the fibrosis and deposition of collagen fibers in the exercise group were significantly higher than that in the normal control group,the degree of fibrosis in the acupuncture group was significantly lower than that in the exercise group. Compared with the normal control group, the expression levels of Collagen Ⅰ, TGF-ß1, CTGF and p-ERK/ERK in the exercise group was significantly higher (P<0.01，P<0.05). After EA interventions, the increased levels of the above indicators were significantly reversed (P<0.05，P<0.01) apart from p-ERK/ERK which had a downward trend, but the difference was not statistically significant. CONCLUSION: The accumulation of chronic sports injury can lead to the deposition of collagen fibers in skeletal muscle, which leads to the fibrosis of skeletal muscle. Acupuncture can inhibit skeletal muscle fibrosis via down-regulating TGF-ß1/ERK/CTGF signaling pathway.

A Review of the Role of Endo/Sarcoplasmic Reticulum-Mitochondria Ca2+ Transport in Diseases and Skeletal Muscle Function.

The physical contact site between a mitochondrion and endoplasmic reticulum (ER), named the mitochondria-associated membrane (MAM), has emerged as a fundamental platform for regulating the functions of the two organelles and several cellular processes. This includes Ca2+ transport from the ER to mitochondria, mitochondrial dynamics, autophagy, apoptosis signalling, ER stress signalling, redox reaction, and membrane structure maintenance. Consequently, the MAM is suggested to be involved in, and as a possible therapeutic target for, some common diseases and impairment in skeletal muscle function, such as insulin resistance and diabetes, obesity, neurodegenerative diseases, Duchenne muscular dystrophy, age-related muscle atrophy, and exercise-induced muscle damage. In the past decade, evidence suggests that alterations in Ca2+ transport from the ER to mitochondria, mediated by the macromolecular complex formed by IP3R, Grp75, and VDAC1, may be a universal mechanism for how ER-mitochondria cross-talk is involved in different physiological/pathological conditions mentioned above. A better understanding of the ER (or sarcoplasmic reticulum in muscle)-mitochondria Ca2+ transport system may provide a new perspective for exploring the mechanism of how the MAM is involved in the pathology of diseases and skeletal muscle dysfunction. This review provides a summary of recent research findings in this area.

Induction of mitophagy in C2C12 cells by electrical pulse stimulation involves increasing the level of the mitochondrial receptor FUNDC1 through the AMPK-ULK1 pathway.

The mitochondrial receptor protein FUN14 domain-containing-1 (FUNDC1) can induce mitophagy under hypoxic conditions, as well as playing important roles in normal metabolism and intracellular homeostasis. Exercise not only elevates mitochondrial biosynthesis, but also exerts a significant impact on mitochondrial fission, integration and mitophagy. However, it is still not clear whether FUNDC1 plays a regulatory role in this context. Electrical pulse stimulation (EPS) of cultured myotubes is widely used as an in vitro model of muscle contraction. We simulated the contraction of C2C12 myotubes by EPS (15 V, 1 Hz, 2 ms, 1 h) to examine the role of FUNDC1 in mitophagy. EPS was found to induce mitophagy by activating the AMPK-ULK1 pathway to an even greater extent than AICAR and FUNDC1 is involved in the associated mitophagy. However, when AMPK is inhibited, other pathways may regulate mitophagy. Our findings indicate that mitophagy helps maintain the normal functions of mitochondria. EPS of C2C12 myotubes results in contraction, induction of mitophagy and potential activation of the AMPK-ULK1 pathway that promotes the expression of FUNDC1.

[Effects of high-load exercise induced skeletal muscle injury on autophagy ultrastructure and Beclin1 and LC3-II / I in rats].

OBJECTIVE: To investigate the effects of high-load eccentric exercise on the ultrastructure of autophagy and the autophagy-related proteins Beclin1 and LC3II / I in rats. METHODS: Forty-eight SD male rats were randomly divided into control group (C, n=8) and high-load eccentric exercise group (E, n=40) after adaptive training. Group E was run downhill for 90 minutes on the running platform, and soleus muscles were collected at 0, 12, 24, 48 and 72 hours after exercise. Transmission electron microscopy was used to observe the ultrastructural changes of skeletal muscle autophagosomes. Western blot was used to detect the expressions of Beclin1 and LC3II / I protein. Immunofluorescence was used to observe the localization and content of LC3. RESULTS: The number of soleus muscle autophagosomes in group E was increased at 0, 12 and 24 hours after exercise, and LC3 autophagic fluorescence was significantly increased (P＜0.01), while autophagic fluorescence at 48 hours after exercise was still increased significantly (P＜0.05). Beclin1 and LC3II / I expression levels were increased after high-load centrifugal intervention (P＜0.05), and were peaked at 12 h～24 h after exercise (P＜0.01), and fully recovered at 72 h after exercise. CONCLUSION: High-load eccentric exercise can induce ultrastructural changes in skeletal muscle autophagy and increase the expression of autophagy protein. The peak value appears at 12 hours after exercise. The above may be one of the reasons for the decline in skeletal muscle function caused by sports injury.

[Effects of exercises with different durations and intensities on mitochondrial autophagy and FUNDC1 expression in rat skeletal muscles].

The aim of the present study was to investigate the effects of exercises with different durations and intensities on mitochondrial autophagy and FUNDC1 in rat skeletal muscles. Sixty male Sprague-Dawley rats were randomly divided into 2- and 4-week control groups (Con), moderate-intensity exercise groups (M-ex groups, treadmill exercise, 16 m/min, 1 h/d, 6 d/week), and high-intensity exercise groups (Hi-ex groups, treadmill exercise, 35 m/min, 20 min/d, 6 d/week). The bilateral soleus muscles were separated after the intervention, and paraffin sections were prepared for transmission electron microscopy. ELISA method was used to detect the content of citrate synthase (CS). The co-localizations of microtubule-associated protein 1 light chain 3 (LC3)/cytochrome c oxidase IV (COX-IV), FUNDC1/COX-IV and LC3/FUNDC1 were observed by immunofluorescent staining in frozen sections. The skeletal muscle mitochondria were extracted, and the expression of autophagy-related proteins, including AMPKα, p-AMPKα, Unc-51 like kinase 1 (ULK1), FUNDC1, LC3 and p62, were detected by Western blot. The results showed that exercise increased mitochondrial function, i.e. peroxisome proliferator-activated receptor γ co-activator-1α (PGC-1α), COX-I protein expression levels and CS content. There was no difference of mitochondrial function parameters between 2-week M-ex and 2-week Hi-ex groups, while mitochondrial function of 4-weeks Hi-ex group was significantly lower than that of 4-week M-ex group. Under the same exercise intensity, mitochondrial autophagy activation in skeletal muscle of 4-week exercise was higher than that in 2-week exercise group; Under the same duration of exercise, mitochondrial autophagy activation of Hi-ex group was higher than that in M-ex group. Both 2- and 4-week exercise intervention increased LC3/COX-IV, COX-IV/FUNDC1, and FUNDC1/LC3 co-localizations. Exercise increased LC3-II/LC3-I ratio, down-regulated p62 protein expression level, up-regulated FUNDC1, ULK1 protein expression levels and AMPKα phosphorylation, and the changes of these proteins in 4-week Hi-ex group were significantly greater than those in 4-week M-ex group. These results suggest exercise induces mitochondrial autophagy in skeletal muscles, and the activity of autophagy is related to the duration and intensity of exercise. The induction mechanism of exercise may involve the mediation of FUNDC1 expression through AMPK-ULK1 pathway.

Increased miR-34c mediates synaptic deficits by targeting synaptotagmin 1 through ROS-JNK-p53 pathway in Alzheimer's Disease.

Alzheimer's disease (AD) and cancer have inverse relationship in many aspects. Some tumor suppressors, including miR-34c, are decreased in cancer but increased in AD. The upstream regulatory pathways and the downstream mechanisms of miR-34c in AD remain to be investigated. The expression of miR-34c was detected by RT-qPCR in oxidative stressed neurons, hippocampus of SAMP8 mice, or serum of patients with amnestic mild cognitive impairment (aMCI). Dual luciferase assay was performed to confirm the binding sites of miR-34c in its target mRNA. The Morris water maze (MWM) was used to evaluate learning and memory in SAMP8 mice administrated with miR-34c antagomir (AM34c). Golgi staining was used to evaluate the synaptic function and structure. The dramatically increased miR-34c was mediated by ROS-JNK-p53 pathway and negatively regulated synaptotagmin 1 (SYT1) expression by targeting the 3'-untranslated region (3'-UTR) of syt1 in AD. The expression of SYT1 protein was reduced by over expression of miR-34c in the HT-22 cells and vice versa. Administration of AM34c by the third ventricle injection or intranasal delivery markedly increased the brain levels of SYT1 and ameliorated the cognitive function in SAMP8 mice. The serum miR-34c was significantly increased in patients with aMCI and might be a predictive biomarker for diagnosis of aMCI. These results indicated that increased miR-34c mediated synaptic and memory deficits by targeting SYT1 through ROS-JNK-p53 pathway and the miR-34c/SYT1 pathway could be considered as a promising novel therapeutic target for patients with AD.

Downhill Running Acutely Elicits Mitophagy in Rat Soleus Muscle.

PURPOSE: This study aimed to investigate the effects of downhill treadmill running on mitochondrial structure/function and expression levels of mitophagy-related proteins in rat skeletal muscle. METHODS: A total of 48 male adult Sprague-Dawley rats were randomly divided into a control group (C, n = 8) and an exercise group (E, n = 40). Rats in the E group were exercised on a treadmill down a 16° decline at 16 m·min for 90 min and were further divided into 0 h (E0), 12 h (E12), 24 h (E24), 48 h (E48), and 72 h (E72) postexercise subgroups (n = 8 each). At each time point, the soleus muscle was collected under full anesthesia. Mitochondrial ultrastructural changes in skeletal muscle were observed by a transmission electron microscope. The content of quantitative enzyme citrate synthase and the activities of mitochondrial respiratory chain complex II and complex IV were measured by enzyme-linked immunosorbent assay. Protein expressions of skeletal muscle cytochrome c oxidase subunit 1 (COX1), PTEN-induced putative kinase 1 (PINK1), and mitochondrial Parkin microtubule-associated protein 1 light chain 3 (LC3) were determined by Western blot. Mitochondrial colocalizations with Parkin, ubiquitin (Ub), p62/sequestosome 1 (p62), and LC3 were measured by the immunofluorescence double labeling technique. RESULTS: After downhill treadmill running, the skeletal muscle mitochondrial structure changed dramatically, and a large amount of mitophagosomes were observed; the citrate synthase content and complex II activity were significantly lower (P < 0.05), whereas complex IV activity and COX1 protein level remained unchanged; the expression levels of PINK1, Parkin, Ub, p62, and LC3 were significantly higher than those in the C group (P < 0.05 or P < 0.01). CONCLUSION: A session of downhill treadmill running activated the PINK1/Parkin pathway and facilitated mitochondrial colocalizations with Ub, p62, and LC3, causing mitophagy and mitochondrial damage within the skeletal muscle.