Changfa Tang

Type 2 diabetes mellitus (T2DM) is characterized by skeletal muscle insulin resistance, which contributes to systemic metabolic dysregulation and diabetic myopathy (DM), a complication involving the loss of muscle mass and contractile function. Although hypoxic exercise has demonstrated metabolic benefits in chronic diseases, its efficacy against DM remains unclear. We hypothesized that hypoxic exercise would be more effective than normoxic exercise in ameliorating diabetic myopathy-associated skeletal muscle abnormalities. Accordingly, adult zebrafish underwent an 8-week high-glucose intervention combining high-glucose feeding and glucose immersion to establish a T2DM-associated diabetic myopathy model and were subsequently subjected to 5 weeks of normoxic or hypoxic exercise (28.8 cm/s, corresponding to 70% of critical swimming speed (Ucrit) determined under normoxic conditions, 2 h/day, 5 days/week) to compare their effects on skeletal muscle outcomes. Hypoxic exercise produced greater improvements in glucose tolerance and locomotor performance than normoxic exercise, while the effects on skeletal muscle morphological and atrophy-related indices varied across outcomes. Both normoxic exercise and intermittent hypoxic exposure altered the abundance of mitochondrial quality-control-related proteins in the skeletal muscle of zebrafish with diabetic myopathy, whereas hypoxic exercise produced more pronounced changes in several of these proteins. Moreover, hypoxic exercise more markedly increased the abundance of mitochondrial respiratory-chain proteins than aerobic exercise or intermittent hypoxic exposure alone. Marked reactive oxygen species (ROS) accumulation was observed in the skeletal muscle of zebrafish with diabetic myopathy. Both aerobic and hypoxic exercise effectively reduced excessive ROS production, with hypoxic exercise producing the greater effect. Analysis of Foxo3a and its phosphorylation showed that p-Foxo3a expression decreased most prominently in the T2DM hypoxia exercise (DHE) group, indicating that hypoxic exercise is associated with modulation of Hif1a/Foxo3a-related signaling. Hypoxic exercise was associated with greater Hif1a protein abundance and lower Foxo3a Ser253 phosphorylation than normoxic exercise, accompanied by improved mitochondrial quality control and reduced ROS accumulation. In conclusion, hypoxic exercise ameliorated diabetic skeletal myopathy and was accompanied by modulation of Hif1a/Foxo3a-related signaling, more favorable mitochondrial morphology, altered abundance of mitochondrial quality-control-related and respiratory-chain proteins, and reduced dihydroethidium-detectable oxidative signals.

Currently, effective disease-modifying treatments for Parkinson’s disease (PD) remain lacking. Although exercise has been confirmed to exert neuroprotective effects against PD, its specific molecular mechanisms remain unclear. In particular, the causal role of the Nuclear Factor E2-related Factor 2 (Nrf2)–antioxidant response element (ARE) signaling axis in this process has not been clearly elucidated. This study aimed to provide direct causal evidence that regular treadmill exercise protects the substantia nigra pars compacta (SNc)–striatal dopaminergic system by activating the Nrf2-ARE pathway. The results showed that exercise significantly improved motor function deficits in PD mice, preserved the number of TH-positive neurons, and restored striatal dopamine homeostasis. Mechanistically, exercise activated the Nrf2-ARE pathway, thereby inhibiting the accumulation of mitochondrial ROS (mtROS) and the activation of pro-inflammatory amoeboid microglia in the substantia nigra. Crucially, the improvements in behavioral, neuropathological, and neurochemical indicators induced by exercise were completely reversed, returning to levels comparable to those in the sedentary model group. In conclusion, this study provides clear pharmacological evidence that the neuroprotective effect of regular treadmill exercise against chronic PD strictly depends on the Nrf2-ARE pathway. These findings indicate that Nrf2 is a key mechanistic node linking exercise and neuroprotection, providing reliable preclinical evidence for Nrf2-targeted disease-modifying strategies in PD rehabilitation.

Objectives: In the wake of the COVID-19 pandemic, declines in physical fitness and psychological resilience among adolescents with overweight/obesity have underscored the need for effective and feasible school-based behavioural interventions. This study compared the effects of High-Intensity Functional Training (HIFT) and Moderate-Intensity Continuous Training (MICT) on body composition, physical fitness, and multidimensional mental health in overweight/obese adolescents. Methods: In this randomized controlled trial, adolescents aged 11–12 years with overweight/obesity were assigned to an 8-week school-based intervention of HIFT, rhythm-/music-accompanied MICT, or a control condition (three sessions per week). Body composition, physical fitness, mood states, and mental health were assessed before and after the intervention. Dietary intake was monitored to ensure stability throughout the study period. Results: Both HIFT and rhythm-based MICT improved body composition, physical fitness, and psychological outcomes compared with the control group. MICT showed stronger effects in reducing overall adiposity and attenuating negative mood and internalizing symptoms such as anxiety and depressive mood. In contrast, HIFT produced greater improvements in cardiorespiratory fitness, muscular fitness and power, and positive mood dimensions including vigor and self-esteem, and showed additional benefits for interpersonal sensitivity. Discussion: Under real-world school conditions, both HIFT and rhythm-based MICT improved body composition, fitness, and mental wellbeing in adolescents with overweight/obesity, but with differential response profiles. These findings support a more tailored (“precision-oriented”) selection of school-feasible exercise modalities based on prioritized physical and psychological targets. Clinical Trial Registration: https://www.chictr.org.cn/showproj.html?proj=61446 , identifier ChiCTR2100048737.

The coronavirus disease 2019 (COVID-19) pandemic has exacerbated physical inactivity and emotional disorders among adolescents, creating an urgent public h

Physiological cardiac hypertrophy represents an adaptive response of the heart to chronic physiological stimuli, including sustained exercise, and is characterized by cardiomyocyte enlargement and structural optimization to enhance pumping efficiency. While several studies on cardiac physiological adaptation have been published recently, a systematic integration of information on exercise-regulated hormonal and growth factor networks remains lacking. To address this limitation, toward the systematization of a ‘multi-dimensional mechanism’ model, here we review the molecular mechanisms underlying exercise-induced physiological cardiac hypertrophy, with particular focus on how physical activity regulates hormones and growth factors including insulin-like growth factor-1, vascular endothelial growth factor, neuregulin-1, and norepinephrine. These mediators activate intricate signaling pathway networks that promote protein synthesis in cardiomyocytes, strengthen myocardial contractility, and induce angiogenesis. The highlighted findings not only provide novel insights into the cardioprotective mechanisms of exercise but also identify potential biomarkers that enable the development of precision exercise prescriptions tailored to individuals with cardiovascular diseases.

There is a growing body of research showing that Alzheimer’s disease (AD) is related to enteric dysbacteriosis. Exercise can be effective in alleviating AD, but the effects that exercise has on the gut microbiota in AD patients needs to be further studied. Through this study, we aimed to investigate the differences in the diversity of gut microorganisms between AD model mice and wild-type mice and the effect that treadmill exercise has on the composition of the gut microbiota in both types of mice. C57BL/6 wild-type mice were randomly divided into a sedentary control group (WTC) and an exercise group (WTE); APP/PS1 double transgenic mice were also randomly divided into a sedentary control group (ADC) and an exercise group (ADE). After the control group remained sedentary for 12 weeks and a 12-week treadmill exercise intervention was adopted for the exercise group, the rectal contents were collected so that they could undergo V3-V4 16S rDNA sequencing, and a comparative analysis of the microbial composition and diversity was also performed. The alpha diversity of the gut microbiota in AD mice was lower than that in wild-type mice, but exercise increased the gut microbial diversity in both types of mice. At the phylum level, the dominant microorganisms in all four groups of mice were Bacteroidetes and Firmicutes. There was an increase in the Bacteroidetes phylum in AD mice. Treadmill exercise reduced the abundance of Bacteroidetes in both groups of mice, whereas the abundance of Firmicutes increased. At the genus level, Muribaculaceae, the Lachnospiraceae_NK4A136_group, Alloprevotella, and Alistipes were in relatively high abundance. Muribaculaceae and Alloprevotella were in greater abundance in AD mice than in wild-type mice, but both decreased after treadmill exercise. Through performing linear discriminant analysis effect size (LEfSe), we found that the dominant strains in AD mice were Campilobacterota, Helicobacteraceae, Escherichia–Shigella, and other malignant bacteria, whereas exercise resulted in an increase in probiotics among the dominant strains in both types of mice. Although gut microbial diversity decreases and malignant bacteria increase in AD mice, treadmill exercise can increase gut microbial diversity and lead to the development of dominant strains of probiotics in both types of mice. These findings provide a basis for applying exercise as a treatment for AD.

Background: Diabetic cardiomyopathy (DCM) is characterized by progressive cardiac dysfunction, metabolic dysregulation, myocardial fibrosis, and mitochondrial impairment. Existing animal models, such as streptozotocin (STZ)-induced models, suffer from high mortality and fail to replicate chronic metabolic dysregulation induced by high-fat diets (HFD), whereas HFD or HFD/STZ-combined rodent models require high maintenance costs. This study aimed to establish a zebrafish HFD-DCM model to facilitate mechanistic exploration and drug discovery. Methods: Eighty wild-type female zebrafish were divided into normal diet (N, 6% fat) and HFD (H, 24% fat) groups and fed the diet for 8 weeks. Metabolic phenotypes were evaluated using intraperitoneal glucose tolerance tests and insulin level analysis. Cardiac function was assessed by using echocardiography (ejection fraction, E peak). Structural, metabolic, and oxidative stress alterations were analyzed by histopathology (H&E, Masson, and Oil Red O staining), molecular assays (RT-qPCR, Western blotting), and mitochondrial structure/function evaluations (respiratory chain activity, transmission electron microscopy, and DHE staining). Results: HFD-fed zebrafish developed obesity, insulin resistance, and impaired glucose tolerance. Echocardiography revealed cardiac hypertrophy, reduced ejection fraction, and diastolic dysfunction. Excessive lipid accumulation, upregulated fibrosis/inflammatory markers, impaired mitochondrial respiration, elevated reactive oxygen species levels, and a disrupted redox balance were observed. Conclusions: We established a female zebrafish HFD model that recapitulates human DCM features, including hypertrophy, metabolic dysregulation, fibrosis, inflammation, and mitochondrial dysfunction. This model offers novel insights into DCM pathogenesis and serves as a valuable platform for mechanistic studies and targeted drug screening.

Background: Growing evidence suggests that the prevalence of sarcopenic obesity (SOB) is on the rise across the globe. However, the key molecular mechanisms behind this disease have not been clarified. Methods: In this experiment, we fed zebrafish a high-fat diet (HFD) for 16 weeks to induce sarcopenic obesity. Results: After a dietary trial, HFD zebrafish exhibited an obese phenotype with skeletal muscle atrophy and decreased swimming capacity. We demonstrated that mitochondrial content and function were abnormal in SOB zebrafish skeletal muscle. These results may be associated with the impairment of mitophagy regulated by the PTEN-induced putative kinase 1 (PINK1)/Parkin (PRKN) pathway. In addition, we also found that NOD-like receptor protein 3 (NLRP3)/gasdermin D (GSDMD) signaling was activated with the upregulation of NLRP3, GSDMD-NT, and mature-IL1β, which indicated that pyroptosis was induced in SOB zebrafish skeletal muscle. Conclusions: Our study identified that impaired mitophagy and pyroptosis were associated with the pathogenesis of SOB. These results could potentially offer novel therapeutic objectives for the treatment of sarcopenic obesity.

Limb-girdle muscular dystrophy (LGMD) is a genetically heterogeneous group of muscle disorders characterized by progressive muscle atrophy and loss of motor function. Over 30 subtypes have been identified and classified into two main inheritance patterns: autosomal dominant and autosomal recessive. Besides primarily affecting skeletal muscle, certain subtypes also impact the cardiac and respiratory muscles, significantly influencing disease progression and patient survival. Substantial progress has been made in understanding the pathogenic genes and molecular mechanisms of LGMD; however, developing disease-modifying therapies remains challenging due to genetic heterogeneity, limitations in gene delivery technologies, and secondary pathological complications. Current treatments are primarily supportive, focusing on symptom management and improving quality of life rather than addressing the underlying cause. This paper summarizes recent advances in LGMD pathogenesis and emerging therapeutic strategies, highlighting progress and remaining challenges in the field.

Background: The Popeye domain containing 3 (POPDC3) protein is essential for the maintenance of skeletal muscle homeostasis. POPDC3 is a pathogenic variant gene of limb‐girdle muscular dystrophy (LGMD), and its variants lead to LGMDR26. At the animal level, zebrafish larvae with popdc3 mutations develop tail curls and muscle atrophy. However, the mechanism of skeletal muscle atrophy induced by POPDC3 variants/loss remains unclear. Methods: Eight‐month‐old male WT and popdc3 mKO zebrafish were used for this research. Loli Track (Denwmark) and Loligo Swimming Respirometer were used to observe the zebrafish's swimming ability. The zebrafish skeletal muscle structure and cross‐sectional area (CSA) were observed and counted by transmission electron microscopy (TEM), H&E and wheat germ agglutinin (WGA). Enriched genes and signalling pathways were analysed using RNA sequencing, and the effects of popdc3 mKO on zebrafish skeletal muscle mitochondrial respiration, biogenesis and dynamics were examined to investigate possible mechanisms. Results: The swimming ability of popdc3 mKO zebrafish was reduced, and as evidenced by the reluctance to move, fewer movement trajectories, the total distance travelled ( p < 0.001), the average velocity of movement ( p < 0.001), oxygen consumption (MO ₂ ) ( p < 0.01), maximum oxygen consumption (MO _2max ) ( p < 0.05), critical swimming speed (U _crit ) ( p < 0.01) and relative swimming speed (U _crit‐r ) ( p < 0.01) were significantly decreased and increased of the exhaustive swimming time ( p < 0.01). In addition, loss of popdc3 reduced zebrafish skeletal muscle weight ( p < 0.001), muscle/body weight ( p < 0.01), myofibre size and CSA ( p < 0.01), increased protein degradation (ubiquitination and autophagy) ( p < 0.05) and decreased protein synthesis ( p < 0.05), suggesting that popdc3 deficiency induces zebrafish skeletal muscle atrophy. Further, popdc3 mKO zebrafish mitochondrial function is reduced, as evidenced by impaired mitochondrial respiration, decreased biogenesis and kinetic imbalance ( p < 0.05). Conclusions: POPDC3, a Popeye protein, plays an important role in controlling mitochondrial function and skeletal muscle mass and strength. Loss of popdc3 decreases mitochondrial respiration and mitochondrial biogenesis, disrupting kinetic homeostasis, which induces mitochondrial dysfunction and impaired protein turnover (reduced synthesis and increased degradation), leading to zebrafish skeletal muscle atrophy.