Antioxidant effects of LEDT in dystrophic muscle cells: involvement of PGC-1α and UCP-3 pathways

A novel role of PvUCP4 in Penaeus vannamei in response to Vibrio alginolyticus challenge

Mitochondria are the energy production and metabolic centers of cells. About 90 % of reactive oxygen species come from mitochondria. Uncoupling proteins (UCPs) have a protective effect against oxidative stress in mitochondria. But this regulatory mechanism remains poorly understood in crustaceans. Here, we investigated the mechanism of PvUCP4 under vibrio alginolyticus challenge. Transcriptome analysis revealed that energy metabolism is a key pathway in the shrimp's immune response. Interestingly, PvUCP4, a mitochondrial uncoupling protein, was found to be inhibited, indicating its potential involvement in the shrimp's resistance to V. alginolyticus. Silencing PvUCP4 upregulates antioxidant enzyme gene expression, including SOD, CAT, and GPX. However, pretreatment with the ROS scavenger N-acetylcysteine revealed that silencing PvUCP4 had no effect on the expression of antioxidant genes. Pretreatment with LPS, a bacterial cell wall component, can rescue partial inhibition of DJ-1/NF-κB signaling pathway related genes caused by overexpression of PvUCP4. In addition, inhibiting PvUCP4 increased the expression of apoptosis-related genes and induced apoptosis. Ultimately, silencing PvUCP4 reduced the survival rate of shrimp under V. alginolyticus stress. Collectively, these findings suggest that PvUCP4 is neither dependent on the antioxidant enzyme system for its antioxidant effects nor on the negative feedback regulation of the DJ-1 pathway.

LED therapy modulates M1/M2 macrophage phenotypes and mitigates dystrophic features in treadmill-trained mdx mice

The mdx mouse phenotype, aggravated by chronic exercise on a treadmill, makes this murine model more reliable for the study of Duchenne muscular dystrophy (DMD) and allows the efficacy of therapeutic interventions to be evaluated. This study aims to investigate the effects of photobiomodulation by light-emitting diode (LED) therapy on functional, biochemical and morphological parameters in treadmill-trained adult mdx animals. Mdx mice were trained for 30 min of treadmill running at a speed of 12 m/min, twice a week for 4 weeks. The LED therapy (850 nm) was applied twice a week to the quadriceps muscle throughout the treadmill running period. LED therapy improved behavioral activity (open field) and muscle function (grip strength and four limb hanging test). Functional benefits correlated with reduced muscle damage; a decrease in the inflammatory process; modulation of the regenerative muscular process and calcium signalling pathways; and a decrease in oxidative stress markers. The striking finding of this work is that LED therapy leads to a shift from the M1 to M2 macrophage phenotype in the treadmill-trained mdx mice, enhancing tissue repair and mitigating the dystrophic features. Our data also imply that the beneficial effects of LED therapy in the dystrophic muscle correlate with the interplay between calcium, oxidative stress and inflammation signalling pathways. Together, these results suggest that photobiomodulation could be a potential adjuvant therapy for dystrophinopathies.

AMONDYS 45 (Casimersen), a Novel Antisense Phosphorodiamidate Morpholino Oligomer: Clinical Considerations for Treatment in Duchenne Muscular Dystrophy

AMONDYS 45 (casimersen) is an antisense oligonucleotide therapy used to treat Duchenne muscular dystrophy (DMD), a rare genetic disorder characterized by a mutation in the DMD gene. Symptoms include progressive muscle weakness, respiratory and cardiac complications, and premature death. Casimersen targets a specific mutation in the DMD gene that results in the absence of dystrophin protein, a key structural component of muscle fibers. While there is currently no cure for DMD, exon-skipping therapy works by restoring the reading frame of the mutated gene, allowing the production of a partially functional dystrophin protein. Clinical trials of casimersen have shown promising results in increasing dystrophin production, as measured by polymerase chain reaction (PCR) droplets when compared to placebo. In a randomized double-blind trial, patients who received casimersen had significantly higher dystrophin levels when compared to those who received placebo. Casimersen therapy is administered through repeated intravenous infusions, although the optimal dosage and duration of treatment are still under investigation. Based on the completed and ongoing clinical trials, casimersen has been well tolerated, with most adverse events being mild and unrelated to casimersen. In 2021, AMONDYS 45 (casimersen) received approval from the US Food and Drug Administration (FDA) for the treatment of Duchene muscular dystrophy in patients with a mutation of the DMD gene that is amenable to exon 45 skipping. These collective findings indicate that casimersen has the potential to elicit functional changes in individuals with DMD, although further studies are necessary to comprehensively evaluate the specific functional improvements. Regardless, the FDA approval and ongoing clinic trials mark a significant milestone in the development of DMD treatments and offer hope for those affected by this debilitating disease.