Emery–Dreifuss muscular dystrophy (EDMD) is caused by mutations in EMD, LMNA, SYNE1, SYNE2, and other related genes. The disease is characterized by joint contractures, muscle weakening and wasting, and heart conduction defects associated with dilated cardiomyopathy. Previous studies demonstrated the activation of fibrogenic molecules such as TGFbeta 2 and CTGF in preclinical models of EDMD2 and increased secretion of TGFbeta 2 in patient serum. A wide screening of patient cells suggested fibrosis, metabolism, and myogenic signaling as the most affected pathways in various EDMD forms. In this study, we show that alpha-smooth muscle actin-positive myofibroblasts are overrepresented in patient fibroblast cultures carrying EMD, LMNA, or SYNE2 mutations, and profibrotic miRNA-21 is upregulated. Upon CRISPR/Cas correction of the mutated EMD or LMNA sequence in EDMD1 or EDMD2 fibroblasts, respectively, we observe a reduced expression of fibrogenic molecules. However, in patient myoblasts, neither fibrogenic proteins nor miRNA-21 were upregulated; instead, miRNA-21-5p was downregulated along with muscle-specific miRNA-133b and miRNA-206, which have a crucial role in muscle cell homeostasis. These observations suggest that the conversion of laminopathic fibroblasts into a profibrotic phenotype is a determinant of EDMD-associated muscle fibrosis, while miRNA-206-dependent defects of laminopathic myoblasts, including altered regulation of VEGF levels, contribute to muscle cell deterioration. Notably, our study provides a proof-of-principle for the application of gene correction to EDMD1 and EDMD2 and presents EDMD1 isogenic cells that exhibit an almost complete rescue of a disease-specific miRNA signature. These cells can be used as experimental models for studying muscular laminopathies.

Limb-Girdle Muscular Dystrophies (LGMDs) are genetically heterogeneous disorders primarily affecting proximal limb muscles. The most common form, LGMDR1, results from biallelic CAPN3 mutations encoding calpain-3, a muscle-specific protease. Recently, growing evidence implicates heterozygous CAPN3 variants in autosomal dominant disease (LGMDD4), with pathogenic mechanisms still incompletely understood. In a retrospective multicenter Italian study of patients harboring monoallelic CAPN3 variants (ClinicalTrials.gov NCT05956132), the p.Asp753Asn substitution was the most frequent change, detected in eight unrelated individuals. These patients, aged 6–80 years, exhibited a spectrum of presentations ranging from asymptomatic hyperCKemia and exertional myalgia to mild proximal weakness. Muscle biopsies showed mild, nonspecific myopathic changes, while calpain-3 expression was variably reduced. Structural modeling suggested that Asp753 may stabilize the Ca²⁺-bound conformation, with substitution potentially disrupting inter-domain interactions. Literature review identified 31 additional reports worldwide, confirming recurrence while highlighting marked phenotypic heterogeneity and limited clinical annotation. The aggregated evidence supports a pathogenic role for p.Asp753Asn, though the precise mechanism, potentially involving a dominant-negative effect, remains to be validated. These findings emphasize diagnostic challenges posed by single CAPN3 variants and underscore the need for integrated clinical, segregation, and functional studies to clarify pathogenic mechanisms, refine counseling, and guide patient-specific rehabilitation and therapeutic strategies.

Background/Objectives: Serum calprotectin is a promising biomarker of inflammation in rheumatoid arthritis (RA), yet real-world longitudinal comparisons across different targeted therapies remain limited. We aimed to evaluate the dynamics and remission-predictive ability of serum calprotectin and C-reactive protein (CRP) in RA patients treated with adalimumab, upadacitinib, or tocilizumab. Methods: In this retrospective cohort study, patients with RA initiating one of the above therapies were included. Serum calprotectin and CRP were measured at baseline, month 3, and month 6. Disease activity was assessed by DAS28 and Clinical Disease Activity Index (CDAI). Linear mixed-effects models adjusted for cumulative prednisone dose were used to assess biomarker trends over time. ROC curve analyses based on CDAI remission (≤2.8) evaluated the discriminative performance of calprotectin and CRP, stratified by treatment subgroups. Results: Sixty patients were enrolled (20 receiving tocilizumab, 20 adalimumab and 20 upadacitinib). Significant reductions in serum calprotectin, CRP, and DAS28 were observed over time (p < 0.001 for all), independent of treatment group. In the overall cohort including baseline, CRP outperformed calprotectin (AUC 0.739 vs. 0.636; p = 0.044). Among patients treated with adalimumab or upadacitinib, calprotectin significantly outperformed CRP (AUC 0.929 vs. 0.857; p = 0.049). In the tocilizumab group, both biomarkers showed similar AUCs (p = 0.888). Conclusions: Serum calprotectin declined significantly after treatment initiation and outperformed CRP in identifying remission under TNFα and JAK inhibition. It also retained a good performance under IL-6 blockade. These findings support its role as a treatment-sensitive biomarker suggesting a complementary role alongside CRP in RA monitoring, particularly in settings where CRP reliability is pharmacologically suppressed.