Clinico-pathological and gene features of 15 nemaline myopathy patients from a single Chinese neuromuscular center.

BACKGROUND: Nemaline myopathy, the most common of the congenital myopathies, is caused by various genetic mutations. In this study, we attempted to investigate the clinical features, muscle pathology and genetic features of 15 patients with nemaline myopathy. RESULTS: Among the 15 patients, there were 9 (60.00%) males and 6 (40.00%) females, and 9 (60.00%) of them came from three families respectively. The age of seeing a doctor ranged from 9 to 52 years old, the age of onset was from 5 to 23 years old, and the duration of disease ranged from 3 to 35 years. Ten out of the 15 patients had high arched palate and elongated face. Only one patient had mild respiratory muscle involvement and none had dysphagia. Muscle biopsies were performed in 9 out of the 15 patients. Pathologically, muscle fibers of different sizes, atrophic muscle fibers and compensatory hypertrophic fibers could be found, and occasionally degenerated and necrotic muscle fibers were observed. Different degrees of nemaline bodies aggregation could be seen in all 9 patients. The distribution of type I and type II muscle fibers were significantly abnormal in patients with nemaline myopathy caused by NEB gene, however, it was basically normal in patients with nemaline myopathy caused by TPM3 gene and ACTA1 gene. Electron microscopic analysis of 6 patients showed that nemaline bodies aggregated between myofibrils were found in 5(83.33%) cases, and most of them were located near the Z band, but no intranuclear rods were found. The gene analysis of 15 NM patients showed that three NM-related genes were harbored, including 11 (73.33%) patients with NEB, 3 (20.00%) patients with TPM3, and 1 (6.67%) patient with ACTA1, respectively. A total of 12 mutation sites were identified and included 10 (83.33%) mutations in exon and 2(16.67%) mutations in intron. CONCLUSIONS: The clinical phenotype of nemaline myopathy is highly heterogeneous. Muscle pathology shows that nemaline bodies aggregation is an important feature for the diagnosis of NM. NEB is the most frequent causative gene in this cohort. The splicing mutation, c.21522 + 3A > G may be the hotspot mutation of the NEB gene in Chinese NM patients.

Analysis of clinical, pathological and gene mutation characteristics in 11 cases of nemaline myopathy caused by NEB gene mutation / 中华神经科杂志

Objective:To investigate the characteristics of clinical, muscle pathology and gene mutation in patients with nemaline myopathy caused by NEB gene mutation.Methods:The clinical and pathological data of patients with nemaline myopathy caused by NEB gene were collected from Neuromuscular Center of Jiaozuo People′s Hospital from January 1997 to January 2020. The next generation sequencing was preformed to detect NEB gene in all patients, and characteristics of gene mutation were analyzed.Results:Among the 11 patients, there were 8 males and 3 females, and 6 of them came from 2 families. The age of seeing a doctor ranged from 11 to 52 years, the age of onset was from 6 to 23 years, and the course of disease ranged from 5 to 35 years. Neurological examination showed that among the 11 patients, 8 patients had high palatal arch and long face. The muscle tone of both upperlimbs was normal, the tendon reflex was depressed, the proximal muscle strength was grade Ⅲ-Ⅴ, and the distal muscle strength was grade Ⅴ. The muscle tone of both lower extremities was reduced and the tendon reflex was absent. The proximal muscle strength was grade Ⅱ-Ⅳ and the distal muscle strength was grade Ⅲ-Ⅴ. No dysphagia or respiratory muscle involvement was found. Muscle biopsies were performed in 7 of the 11 patients, the pathological changes were muscle fibers of different sizes, circular atrophic muscle fibers and compensatory hypertrophic fibers, and occasionally denatured and necrotic muscle fibers were found. Different degrees of rod aggregation could be seen in all the 7 patients. Electron microscopic examination of 5 patients showed that there was rod aggregation between myofibrils, and most of them were located near the Z band, but no intranuclear rod was found. NEB gene was found in all 11 patients, and a total of 9 different mutation sites were detected, including 8 in exon region and 1 in intron region. Among them, c.21522+3A>G was found in 10 cases, c.1623delT was found in 3 cases and c.17611C>T was found in 3 cases. There was 1 case of c.4417C>T, c.2549delA, c.21065dupA, c.3520G>A, c.20943G>A, c.192G>A respectively.Conclusions:The clinical phenotype of nemaline myopathy caused by NEB gene has great heterogeneity. Muscle pathology shows that rod aggregation is an important basis for the diagnosis of this disease. Mutation c.21522+3A>G in intron is the most common mutation in this group of NEB gene. And the novel mutation sites of NEB gene are respectively c.17611C>T, c.2549delA, c.3520G>A, c.21065dupA, c.20943G>A and c.192G>A.

Upregulated ox40l Can Be Inhibited by miR-146a-5p in Condylar Chondrocytes Induced by IL-1ß and TNF-α: A Possible Regulatory Mechanism in Osteoarthritis.

INTRODUCTION: Osteoarthritis (OA) is a common musculoskeletal disease characterized by pain, stiffness, limited activity, occasional effusion, and local inflammation. MiR-146 is one of the noncoding RNA closely related to OA, but the role of miR-146 in OA remains controversial. The tumour necrosis factor receptor OX40 is activated by its cognate ligand OX40L (TNFSF4) and functions as a T-cell costimulatory molecule. The T-cell functions, including cytokine production, expansion, and survival, are enhanced by the OX40 costimulatory signals. METHODS: We established an inflammatory model of condylar chondrocytes induced by IL-1ß and TNF-α and detected the expression of miRNA by miRNA sequencing. Then, cell transfection was used to study the role of miR146a-5p in OA. The Kyoto Encyclopedia of Genes and Genomes (KEGG) and database analysis were used to screen out potential target genes of miR-146a-5p. A dual luciferase activity assay tested whether ox40l is the target gene of miR-146a-5p. RESULTS: MiR-146a-5p and OX40L was upregulated after induced by IL-1ß and TNF-α, miR-146a-5p reduced the production of inflammatory factors but had no effect on chondrophenotypic factors, and ox40l was targeted by miR-146a-5p. CONCLUSION: OX40L and miR-146a-5p of condylar chondrocytes in the inflammatory environment (induced by IL-1ß and TNF-α) were significantly increased, miR-146a-5p is a protective factor in the inflammatory response, which can reduce the production of inflammatory factors, and miR-146a-5p may regulate T-cell-mediated immunity through targeting of ox40l in OA.