Dp71 depleted HBE cells displayed increased DNA damage and apoptosis induced by H2O2

Duchenne muscular dystrophy gene product expression is associated with survival in head and neck squamous cell carcinoma

Mutation of the Duchenne muscular dystrophy (DMD) gene causes neuromuscular disorders, but increasing evidence has implicated DMD in the development and progression of several major cancer types. This study investigates the prognostic and biological significance of DMD expression in head and neck squamous cell carcinoma (HNSCC). Analysis of The Cancer Genome Atlas (TCGA) data revealed that high DMD expression correlates with improved overall (median survival difference: 22 months, p = 0.0083) and progression-free (p = 0.0237) survival. The Dp71ab transcript is most strongly associated with better outcomes (median overall survival: 42 months, p = 0.0007). Notably, DMD expression levels stratify HPV-positive patients, identifying a DMD low/HPV-positive subgroup with poor outcomes. Immunohistochemical analysis of 50 HNSCC tissue cases confirmed dystrophin localisation in the nucleus and cytoplasm, with high nuclear expression linked to longer overall survival (mean difference: 31 months, p = 0.0497). Functional assays in HNSCC cells showed that Dp71ab overexpression disrupts nuclear morphology and reduces proliferation. Differential gene expression analysis additionally identified 388 upregulated and 30 downregulated genes, with pathways linked to muscle processes, ribosome biogenesis and non-coding RNA regulation. These findings highlight DMD as a potential biomarker and/or therapeutic target in HNSCC, warranting further mechanistic studies of Dp71 isoforms.

Oxidative stress as a key modulator of cell fate decision in osteoarthritis and osteoporosis: a narrative review

During aging and after traumatic injuries, cartilage and bone cells are exposed to various pathophysiologic mediators, including reactive oxygen species (ROS), damage-associated molecular patterns, and proinflammatory cytokines. This detrimental environment triggers cellular stress and subsequent dysfunction, which not only contributes to the development of associated diseases, that is, osteoporosis and osteoarthritis, but also impairs regenerative processes. To counter ROS-mediated stress and reduce the overall tissue damage, cells possess diverse defense mechanisms. However, cellular antioxidative capacities are limited and thus ROS accumulation can lead to aberrant cell fate decisions, which have adverse effects on cartilage and bone homeostasis. In this narrative review, we address oxidative stress as a major driver of pathophysiologic processes in cartilage and bone, including senescence, misdirected differentiation, cell death, mitochondrial dysfunction, and impaired mitophagy by illustrating the consequences on tissue homeostasis and regeneration. Moreover, we elaborate cellular defense mechanisms, with a particular focus on oxidative stress response and mitophagy, and briefly discuss respective therapeutic strategies to improve cell and tissue protection.

Dystrophin Dp71 and the Neuropathophysiology of Duchenne Muscular Dystrophy

Duchenne muscular dystrophy (DMD) is caused by frameshift mutations in the DMD gene that prevent the body-wide translation of its protein product, dystrophin. Besides a severe muscle phenotype, cognitive impairment and neuropsychiatric symptoms are prevalent. Dystrophin protein 71 (Dp71) is the major DMD gene product expressed in the brain and mutations affecting its expression are associated with the DMD neuropsychiatric syndrome. As with dystrophin in muscle, Dp71 localises to dystrophin-associated protein complexes in the brain. However, unlike in skeletal muscle; in the brain, Dp71 is alternatively spliced to produce many isoforms with differential subcellular localisations and diverse cellular functions. These include neuronal differentiation, adhesion, cell division and excitatory synapse organisation as well as nuclear functions such as nuclear scaffolding and DNA repair. In this review, we first describe brain involvement in DMD and the abnormalities observed in the DMD brain. We then review the gene expression, RNA processing and functions of Dp71. We review genotype-phenotype correlations and discuss emerging cellular/tissue evidence for the involvement of Dp71 in the neuropathophysiology of DMD. The literature suggests changes observed in the DMD brain are neurodevelopmental in origin and that their risk and severity is associated with a cumulative loss of distal DMD gene products such as Dp71. The high risk of neuropsychiatric syndromes in Duchenne patients warrants early intervention to achieve the best possible quality of life. Unravelling the function and pathophysiological significance of dystrophin in the brain has become a high research priority to inform the development of brain-targeting treatments for Duchenne.