Muscle fibrosis is a major driver of progression in diverse myopathies, yet the conserved molecular mediators of this process in humans remain poorly defined. Here, we identify collagen VI as a common regeneration-impairing extracellular matrix (ECM) component across three distinct human myopathies: Duchenne Muscular Dystrophy (DMD), Oculopharyngeal Muscular Dystrophy (OPMD), and Inclusion Body Myositis (IBM). Proteomic profiling of fibrotic biopsies reveals consistent upregulation of collagen VI and laminin γ1, alongside disease-specific alterations. Fibroadipogenic progenitors (FAPs) are the predominant source of these ECM components, including collagen VI and laminin γ1. Functionally, xenotransplantation of patient-derived FAPs into regenerating mouse muscle induces localized collagen deposition, myofiber atrophy, and depletion of Pax7⁺ muscle stem cells. Mechanistic assays demonstrate that FAP-derived collagen VI is sufficient to impair myogenic fusion, while silencing COL6 in patient FAPs restores fusion capacity, directly linking pathological collagen VI deposition to regeneration failure. Our findings uncover collagen VI as a conserved effector of fibrosis and stem cell niche disruption in human myopathies, positioning it as a potential therapeutic target across genetically and clinically distinct muscle diseases.

LDB1 encodes transcriptional regulator protein LIM domain-binding protein 1, which plays an important role in neurogenesis. Few C-terminal likely gene-disrupting (LGD) variants have been reported in the literature in individuals with congenital ventriculomegaly. Through international collaboration, we now assembled a cohort of 16 individuals with de novo variants affecting various regions of LDB1. Eleven variants affect either the whole gene or the N-terminal dimerization domain (including gene deletions, as well as nonsense-mediated mRNA decay (NMD)-sensitive LGD and missense variants), and five variants (missense or NMD-escaping LGD variants) affect only the C terminus of LDB1 containing the LIM interaction domain. All individuals showed variable neurodevelopmental phenotypes, including developmental delay and behavioral anomalies. In line with literature reports, individuals harboring C-terminal variants additionally presented with ventriculomegaly, which suggests a potential genotype-phenotype correlation. In accordance, we found diverging pathomechanisms in vitro: N-terminal missense variants disrupt homodimerization of LDB1, likely leading to a loss of function, while C-terminal variants impair interaction with the essential partner LHX2 in a dominant-negative manner. These findings were confirmed in vivo in Drosophila melanogaster. Toxicity of overexpressed human LDB1 in Drosophila was not observed with N-terminal missense variants but was exacerbated by C-terminal variants. Similarly, phenotypes associated with LDB1/chi loss were rescued by overexpression of wild-type LDB1 but not by LDB1 harboring N-terminal missense variants or by C-terminal variants that even worsened phenotypes. In summary, our findings indicate that de novo variants in LDB1 are linked to two overlapping but distinct neurodevelopmental phenotypes based on variant location and propose two separate pathomechanisms underlying LDB1-related neurodevelopmental disorders.

Janus kinase (JAK) inhibitors have emerged as a transformative therapeutic class across autoimmune diseases by targeting multiple cytokine networks implicated in inflammation and fibrosis. Beyond inflammatory arthritis, increasing evidence supports their potential efficacy in connective tissue diseases such as idiopathic inflammatory myopathies, systemic sclerosis, primary Sjögren's disease, and systemic lupus erythematosus. Through modulation of type I/II interferon and interleukin signaling, JAK inhibition exerts broad anti-inflammatory and antifibrotic effects, translating into clinical improvements in cutaneous, articular, and pulmonary domains. Early clinical trials and real-world data confirm meaningful responses in refractory disease, though randomized evidence remains limited. Overall, JAK inhibitors represent a promising, mechanistically grounded option for systemic autoimmune diseases, with ongoing studies expected to refine selectivity, indications, and long-term safety profiles.

Statin intolerance and side effects such as low-level myopathy limit statin use and the dose for optimal cholesterol lowering. We found that priming the NLRP3 inflammasome with bacterial components like lipopolysaccharide lowered the dose of statins that caused side effects in muscle cells. We then built models of low-level statin myopathy and found that muscle cell-autonomous statin-induced myopathy occurs through the NLRP3 inflammasome in vitro and in mice. Statin-induced muscle cell death and higher Atrogin-1 were prevented by blocking NLRP3 or restoring isoprenoids but not cholesterol. Statins reduced glycolysis in muscle cells, which required lower protein prenylation. Statins lowered YAP effector genes and promoted nuclear accumulation of FOXO. Activating YAP, restoring isoprenoids, or blocking NLRP3 mitigated nuclear FOXO accumulation, statin-induced muscle atrophy, and statin-mediated lowering of protein synthesis. These results define a statin-induced myopathy pathway where metabolic danger engages the NLRP3 inflammasome and YAP via lower prenylation independent of cholesterol.

Neurogenic bladder (NB) is a debilitating urological disorder characterized by progressive bladder remodeling, fibrosis, and functional deterioration, yet effective mechanism-based therapies remain limited. The AKT/mTOR signaling pathway is a central regulator of cellular growth, inflammation, and tissue remodeling, but its contribution to NB pathogenesis remains incompletely understood. In this study, we established an NB rat model by bilateral L6-S1 spinal nerve transection and evaluated the therapeutic effects of resveratrol. Urodynamic and histological analyses showed that resveratrol reduced residual volume and pressure change, improved bladder compliance, attenuated bladder enlargement and fibrosis, and alleviated secondary renal injury. In addition, resveratrol partially restored β III Tubulin immunoreactivity and reduced pathological remodeling in both mucosal and muscular compartments of the bladder. Mechanistically, resveratrol suppressed epithelial-mesenchymal transition (EMT)-like changes, apoptosis, and pyroptosis, as reflected by restoration of E-cadherin, reduction of α-SMA, Bax, cleaved caspase-3, NLRP3, IL-1β, and Caspase-1, and decreased inflammatory cytokine production. These effects were accompanied by marked inhibition of AKT/mTOR/S6K signaling activation in vivo. Consistently, in vitro experiments showed that resveratrol protected urothelial cells from TGF-β1-induced injury, whereas pharmacological re-activation of mTOR with MHY1485 partially reversed its anti-fibrotic and anti-pyroptotic effects. Collectively, these findings indicate that resveratrol alleviates NB-associated bladder injury and fibrosis by inhibiting the AKT/mTOR/S6K signaling pathway, highlighting this pathway as a potential therapeutic target for NB.

Joint effusion (JE) refers to the presence of a pathological collection of fluid in the joint space, and JE is one of the symptoms of the inflammatory process in the temporomandibular joint (TMJ) and it is associated with the presence of TMJ pain. The authors of this study focused on the ultrasonographic evaluation of TMJ capsular distension, capsular width in patients with unilateral anterior disc dislocation. The cohort included 200 patients, 169 women and 31 men, with a mean age of 34.3 years (range 11-82 years). All patients were diagnosed with disc dislocation with reduction. 102 patients were completely pain free, 98 patients reported pain localized to the TMJ area. 28 patients perceived their pain as persistent in the last week before the examination, 70 patients perceived their pain as irregular. The results showed that capsular distension was demonstrably greater in patients with pain than in patients without pain. The increase in capsular distension is not affected by whether the pain is persistent or irregular. Capsular distension is enhanced in patients with TMJ palpation pain and painful dynamic testing. The authors confirm the use of ultrasonography as an ideal method for diagnosing JE. Also an association between the presence of JE and pain in patients with disc dislocation has been demonstrated. Painful lateral palpation and painful dynamic test are clinical signs of JE and thus signs of an intra articular inflammatory process in patients with TMJ pain.

Thymidine kinase 2 deficiency (TK2d) (MIM 609560) is an ultra-rare, autosomal recessive mitochondrial myopathy caused by TK2 variants, leading to mitochondrial DNA depletion and/or multiple deletions. People with thymidine kinase 2 deficiency experience progressive myopathy, bulbar weakness and respiratory insufficiency, often losing the ability to walk, eat and breathe independently. Doxecitine and doxribtimine represents the first approved treatment for patients with thymidine kinase 2 deficiency with age of symptom onset ≤12 years by the US Food and Drug Administration and the European Medicines Agency; previously, disease management was limited to supportive care. We investigated the efficacy and safety of pyrimidine nucleos(t)ide therapy in thymidine kinase 2 deficiency. Patients treated with pyrimidine nucleos(t)ides were pooled from retrospective (NCT03701568, NCT05017818) and prospective (NCT03845712) studies and company-supported Expanded Access Programs. Untreated patients were pooled from literature reviews and a retrospective chart review study (NCT05017818). Patient subgroups were stratified by age of thymidine kinase 2 deficiency symptom onset (≤12 years and >12 years). The primary outcome was survival in 50th-percentile matched pairs of treated and untreated patients. Other outcomes included status of developmental motor milestones, ventilatory and feeding tube support, and safety. In total, 218 patients were included (treated: 104; untreated: 114). Baseline demographics and characteristics were comparable between subgroups. Most patients had an age of symptom onset ≤12 years [treated: 82/104 (78.8%); untreated: 93/114 (81.6%)]. In the age-of-symptom-onset-≤12-years subgroup, restricted mean survival time (95% confidence interval) was 29.2 (28.2, 30.3) years over the 30 years after symptom onset for treated patients and 14.4 (11.1, 17.6) years for untreated patients. Loss of ≥1 acquired motor milestone was more frequent before treatment start than after. Substantially more patients regained ≥1 lost motor milestone after treatment start than before. Ventilatory and feeding support were used across all age-of-symptom-onset subgroups, but some patients reduced or discontinued support after starting treatment and fewer patients initiated support after treatment start than before. Most treatment-emergent adverse events (TEAEs) did not lead to discontinuation. The most frequent TEAE was diarrhoea [43/50 patients (86.0%)], which was generally mild or moderate and resolved with dose reduction. Serious TEAEs occurred in 28/50 patients (56.0%); few were considered to be drug related [4/50 (8.0%)]. In total, 3/67 patients (4.5%) experienced a fatal serious TEAE, which were not considered to be drug related. These findings indicate that pyrimidine nucleos(t)ide therapy improves survival and functional outcomes in people with thymidine kinase 2 deficiency, especially those with age of symptom onset ≤12 years, and has an acceptable safety profile.

Thymidine kinase 2 deficiency (MIM 609560) is an ultra-rare, autosomal recessive mitochondrial disease, resulting in progressive myopathy, respiratory insufficiency and increased risk of early death. Doxecitine and doxribtimine represents the first approved treatment for thymidine kinase 2 deficiency in the USA and the EU; previously, management was restricted to supportive care. The overall understanding of the natural history of thymidine kinase 2 deficiency is limited. Our study describes the baseline characteristics, survival and disease progression of untreated patients with thymidine kinase 2 deficiency as part of one of the largest international datasets to date. Data from individuals with thymidine kinase 2 deficiency identified through the review of published literature and a retrospective chart review study (NCT05017818) were pooled with pretreatment data from patients later treated with pyrimidine nucleos(t)ides (NCT03701568; NCT03845712; NCT05017818; company-supported Expanded Access Programs). Subgroups were stratified by age of thymidine kinase 2 deficiency symptom onset (≤12 years and >12 years). Key outcomes measured included survival, developmental motor milestone attainment, loss, regain and use of ventilatory and feeding support. In total, 257 patients were included in the study. Most patients [n = 199 (77.4%)] had an age of symptom onset ≤12 years, while 49 (19.1%) had an age of symptom onset >12 years; age of onset was missing for 9 (3.5%). Kaplan-Meier survival analyses estimated that the median time (95% confidence interval) from symptom onset to death was 2.6 (1.3, 6.4) years with age of symptom onset ≤12 years and 24.0 (16.0, not applicable) years with age of symptom onset >12 years. Loss of previously acquired motor milestones was observed across both subgroups, though most frequently in those with age of symptom onset ≤12 years [61/75 patients (81.3%) lost ≥1 motor milestone]. Spontaneous regain of lost motor milestones was rare [3/71 patients (4.2%), all with age of symptom onset ≤12 years]. Use of ventilatory support was observed for both subgroups [81/199 patients (40.7%) with age of symptom onset ≤12 years (missing data, n = 73); 23/49 patients (46.9%) with age of symptom onset >12 years (missing data, n = 11)]. Use of feeding tube support was also reported [28/199 patients (14.1%) with age of symptom onset ≤12 years (missing data, n = 121); 4/49 patients (8.2%) with age of symptom onset >12 years (missing data, n = 21)]. This study confirms the severe disease burden and high mortality associated with thymidine kinase 2 deficiency, underscoring the devastating impact on quality of life. This comprehensive dataset provides a valuable resource for informing clinical management and future therapeutic strategies.