Background Dystrophinopathy, a common neuromuscular disorder caused by the absence of dystrophin, currently lacks effective treatments. Systemic transplantation of adipose-derived stem cells (ADSCs) is a promising treatment approach, but its low efficacy remains a challenge. Chemokine system-mediated stem cell homing plays a critical role in systemic transplantation. Here, we investigated whether overexpression of a specific chemokine receptor could improve muscle homing and therapeutic effects of ADSC systemic transplantation in dystrophic mice. Methods We analysed multiple microarray datasets from the Gene Expression Omnibus to identify a candidate chemokine receptor and then evaluated the protein expression of target ligands in different tissues and organs of dystrophic mice. The candidate chemokine receptor was overexpressed using the lentiviral system in mouse ADSCs, which were used for systemic transplantation into the dystrophic mice, followed by evaluation of motor function, stem cell muscle homing, dystrophin expression, and muscle pathology. Results Chemokine-profile analysis identified C–C chemokine receptor (CCR)2 as the potential target for improving ADSC homing. We found that the levels of its ligands C–C chemokine ligand (CCL)2 and CCL7 were higher in muscles than in other tissues and organs of dystrophic mice. Additionally, CCR2 overexpression improved ADSC migration ability and maintained their multilineage-differentiation potentials. Compared with control ADSCs, transplantation of those overexpressing CCR2 displayed better muscle homing and further improved motor function, dystrophin expression, and muscle pathology in dystrophic mice. Conclusions These results demonstrated that CCR2 improved ADSC muscle homing and therapeutic effects following systemic transplantation in dystrophic mice.

Background Dystrophinopathy, a common neuromuscular disorder, includes Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD). Many researches are currently ongoing to develop curative approaches, which results in an urgent need for biomarkers of disease progression and treatment response. This study investigated whether the serum creatinine (SCRN) level can be used as a biomarker of disease progression in dystrophinopathy. Methods We enrolled 377 male patients with dystrophinopathy and 520 male non-dystrophinopathy controls in a cross-sectional study. From this cohort, 113 follow-up patients were enrolled in a longitudinal study. Patients’ demographic information, motor function, muscle fatty infiltration, and muscle dystrophin levels were evaluated. We investigated correlations between these parameters and SCRN levels, and determined changes in SCRN levels with maturation and with motor function changes. Results Our results showed SCRN levels correlated with motor function (FDR < 0.001) and timed test results (FDR between < 0.001–0.012), as well as with muscle fatty infiltration (FDR < 0.001) and dystrophin levels (FDR = 0.015 and 0.001). SCRN levels increased with maturation in control individuals; it slowly increased with maturation in patients with BMD but decreased generally with maturation in patients with DMD. The longitudinal study further demonstrated that SCRN levels were associated with motor function. Conclusions These findings indicated that the SCRN level is a promising biomarker for assessing disease progression in dystrophinopathy and could be used as a potential outcome measure in clinical trials.

Background: Duchenne and Becker muscular dystrophy (DMD/BMD) are X-linked recessively inherited neuromuscular disorders caused by deletions, duplications, or small mutations in the DMD gene. With advances in prenatal diagnosis decreasing the number of affected offspring from carrier mothers, the frequency of de novo variants could increase. Therefore, determining the differences between the carrier and de novo variants of the DMD gene, which are rarely explored, is important for trial planning and genetic diagnosis in the future.Methods: A total of 440 patients, 349 of whom had DMD and 91 had BMD, diagnosed in our department between 2012 and 2019, along with their respective mothers, were included in this study. Multiplex ligation-dependent probe amplification was used to detected deletions and duplications in patients and their mothers. Small mutations were detected using next-generation sequencing in the patients, followed by Sanger sequencing in the mothers.Results: Deletions, duplications, and small mutations were identified in 204, 46, and 99 of the 349 patients with DMD and in 50, 10, and 31 of the 91 patients with BMD, respectively. De novo deletions were more concentrated in hotspot regions than carrier deletions of DMD/BMD. No clear bias was observed in the variant distribution between carriers, de novo duplications, and small mutations in DMD/BMD. The carrier frequency of DMD (61.6%) was lower than that of BMD (69.2%), but the difference was not statistically significant. The carrier frequency of deletions of the DMD gene (51.2%) was significantly lower than those of duplications (75%) and small mutations (81.5%).Conclusion: Compared to de novo deletions, deletions from carrier mothers had a wider distribution. Moreover, there was no significant difference between the carrier frequencies of DMD and BMD. Duplications and small mutations were more commonly inherited, while deletions were present de novo.

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