Acute cold stress induces transient MuRF1 upregulation in the skeletal muscle of zebrafish

Utilizing zebrafish models to elucidate mechanisms and develop therapies for skeletal muscle atrophy

Skeletal muscle atrophy, resulting from an imbalance in muscle protein synthesis and degradation, compromises muscle quality and function, imposing significant burdens on movement and metabolic stability. Animal models are crucial for understanding the mechanisms of skeletal muscle atrophy and developing clinical prevention and treatment strategies. Zebrafish, as small aquatic vertebrates, exhibit high genetic homology with humans and offer advantages such as rapid reproduction, development, and transparent embryos. Their physiological and anatomical similarities to mammals, including a substantial proportion of skeletal muscle and observable swimming behavior reflecting body dysfunction, make zebrafish an ideal model for studying skeletal muscle-related diseases. This review outlines the development of zebrafish skeletal muscle and highlights key pathways regulating muscle proteins, emphasizing their anatomical and genetic consistency with humans. Various zebrafish models of skeletal muscle atrophy created through physical, chemical, and gene-editing methods are systematically summarized. Current challenges and proposed improvement strategies are also discussed to enhance the reliability and applicability of zebrafish models, providing a comprehensive reference for advancing research on skeletal muscle atrophy.

Cold water immersion regulates NLRP3 inflammasome pathway in the rat skeletal muscle after eccentric exercise by regulating the ubiquitin proteasome related proteins

BACKGROUND

Eccentric exercise (ECC) can induce NLRP3-related inflammation in skeletal muscle tissue. Limited available data have shown that Cold water immersion (CWI) after ECC can suppress skeletal muscle inflammation. This study aims to investigate the effect of CWI after ECC on the NLRP3 inflammasome pathway, and the expression of ubiquitin-proteasome-related proteins (UPPs) in the skeletal muscle of rats.

METHODS

Twenty-five male Wistar rats were randomly divided into control, ECC, ECC + CWI, ECC + NWI (normal water immersion), and ECC + AR (active recovery) groups. The Eccentric exercise consisted of 90 min of downhill running on a treadmill with a speed of 16 m/min and -16° incline. Animals in the NWI and CWI groups were immersed in water at 25 °C and 10 °C after ECC. Eventually, The soleus muscle was isolated and the expression of NLRP3, caspase-1, FBXL2, TRIM31, and PARKIN was evaluated by western blot. Tissue levels of IL-1β and IL-18 were measured by ELISA assay.

RESULTS

ECC significantly increased the expression of NLRP3, caspase-1, and the tissue levels of IL-1β and IL-18 compared to the control group. After ECC, FBXL2, and PARKIN were downregulated, whereas TRIM31 was up-regulated (P < 0.05). CWI after ECC suppressed the NLRP3 inflammasome components and increased the protein levels of FBXL2 and TRIM31 at higher levels than other recovery methods (P < 0.05). CWI and AR had the same increase in PARKIN expression and the same decrease in CK level compared to the ECC group (P < 0.05).

CONCLUSION

Our results indicated that CWI increased the expression of NLRP3-related UPPs in concomitant with suppression of NLRP3 in the soleus muscle of rats after ECC. As a result the beneficial effects of CWI on the attenuation of skeletal muscle inflammation may contribute to an alteration of UPPs expression.

Integrated cellular response of the zebrafish (Danio rerio) heart to temperature change

A decrease in environmental temperature represents a challenge to the cardiovascular system of ectotherms. To gain insight into the cellular changes that occur during cold exposure and cold acclimation we characterized the cardiac phosphoproteome and proteome of zebrafish following 24 h or 1 week exposure to 20°C from 27°C; or at multiple points during 6 weeks of acclimation to 20°C from 27°C. Our results indicate that cold exposure causes an increase in mitogen-activated protein kinase signalling, the activation of stretch-sensitive pathways, cellular remodelling via ubiquitin-dependent pathways and changes to the phosphorylation state of proteins that regulate myofilament structure and function including desmin and troponin T. Cold acclimation (2-6 weeks) led to a decrease in multiple components of the electron transport chain through time, but an increase in proteins for lipid transport, lipid metabolism, the incorporation of polyunsaturated fatty acids into membranes and protein turnover. For example, there was an increase in the levels of apolipoprotein C, prostaglandin reductase-3 and surfeit locus protein 4, involved in lipid transport, lipid metabolism and lipid membrane remodelling. Gill opercular movements suggest that oxygen utilization during cold acclimation is reduced. Neither the amount of food consumed relative to body mass nor body condition was affected by acclimation. These results suggest that while oxygen uptake was reduced, energy homeostasis was maintained. This study highlights that the response of zebrafish to a decrease in temperature is dynamic through time and that investment in the proteomic response increases with the duration of exposure.

Zebrafish as an Emerging Model for Sarcopenia: Considerations, Current Insights, and Future Directions

Sarcopenia poses a significant challenge to public health and can severely impact the quality of life of aging populations. Despite extensive efforts to study muscle degeneration using traditional animal models, there is still a lack of effective diagnostic tools, precise biomarkers, and treatments for sarcopenia. Zebrafish models have emerged as powerful tools in biomedical research, providing unique insights into age-related muscle disorders like sarcopenia. The advantages of using zebrafish models include their rapid growth outside of the embryo, optical transparency during early developmental stages, high reproductive potential, ease of husbandry, compact size, and genetic tractability. By deepening our understanding of the molecular processes underlying sarcopenia, we may develop novel diagnostic tools and effective treatments that can improve the lives of aging individuals affected by this condition. This review aims to explore the unique advantages of zebrafish as a model for sarcopenia research, highlight recent breakthroughs, outline potential avenues for future investigations, and emphasize the distinctive contributions that zebrafish models offer. Our research endeavors to contribute significantly to address the urgent need for practical solutions to reduce the impact of sarcopenia on aging populations, ultimately striving to enhance the quality of life for individuals affected by this condition.

Characterization of pig skeletal muscle transcriptomes in response to low temperature

OBJECTIVES

The response of mammals to cold environment is a complex physiological activity, and its underlying mechanism must be analyzed from multiple perspectives. Skeletal muscle is an important thermogenic tissue that maintains body temperature in mammals. We dissected the molecular mechanism of pig skeletal muscle response to a cold environment by performing comparative transcriptome analysis in the Enshi black pig.

METHODS

Three pigs were subjected to acute cold stress (3 days), three pigs were subjected to cold acclimation (58 days), and three pigs were used as controls. RNA-seq was used to screen the differentially expressed genes (DEGs) of skeletal muscle.

RESULTS

Using RNA-seq methods, we identified 1241 DEGs within the acute cold stress group and 1886 DEGs within the cold acclimation group. Prolonged cold exposure induced more gene expression changes. A total of 540 key cold-responsive DEGs were found, and their trends were consistent within the acute cold stress group and cold acclimation group. Gene expression pattern analysis showed that there were significant differences between the low-temperature treatment groups and the control group, and there were also differences between individuals after long-term low-temperature treatment. Analysis of DEGs revealed that 134 pathways were significantly enriched in the cold adaptation group, 98 pathways were significantly enriched in the acute cold stress group, and 71 pathways were shared between the two groups. The 71 shared pathways were mainly related to lipid, amino acid, and carbohydrate metabolism; signal transduction; endocrine, immune, and nervous system; cardiovascular disease; infectious diseases caused by bacteria or viruses; and neurodegenerative disease.

CONCLUSIONS

In conclusion, this study provides insights into the molecular mechanism of porcine skeletal muscle response under low-temperature environment. The data may assist further research on the mechanism of pig response to cold exposure.

High expression of Sam68 contributes to metastasis by regulating vimentin expression and a motile phenotype in oral squamous cell carcinoma

The present study aimed to investigate the clinical and biological significance of Src-associated in mitosis 68 kDa (Sam68) in oral squamous cell carcinoma (OSCC). Immunohistochemical analysis was performed on tissue samples obtained from 77 patients with OSCC. Univariate analysis revealed that the high expression of Sam68 was significantly correlated with advanced pathological T stage (P=0.01), positive lymphovascular invasion (P=0.01), and pathological cervical lymph node metastasis (P<0.01). Moreover, multivariate analysis demonstrated that the high expression of Sam68 was an independent predictive factor for cervical lymph node metastasis (odds ratio, 4.39; 95% confidence interval, 1.49-14.23; P<0.01). These results indicated that high Sam68 expression contributed to tumor progression, especially cervical lymph node metastasis, in OSCC. mRNA sequencing was also performed to assess the changes in the transcriptome between OSCC cells with Sam68 knockdown and control cells with the aim of elucidating the biological roles of Sam68. Gene Ontology enrichment analysis revealed that downregulated differentially expressed genes (DEGs) were concentrated in some biological processes related to epithelial-mesenchymal transition. Among these DEGs, it was established that vimentin was particularly downregulated in these cells. It was also confirmed that Sam68 knockdown reduced the motility of OSCC cells. Furthermore, the immunohistochemical study of vimentin identified the association between vimentin expression and Sam68 expression as well as cervical lymph node metastasis. In conclusion, the present study suggested that the high expression of Sam68 may contribute to metastasis by regulating vimentin expression and a motile mesenchymal phenotype in OSCC.