The development of bone in human body and the maintenance of bone mass in adulthood are regulated by a variety of biological factors. Myocyte enhancer factor 2C (MEF2C), as one of the many factors regulating bone tissue development and balance, has been shown to play a key role in bone development and metabolism. However, there is limited systematic analysis on the effects of MEF2C on bone tissue. This article reviews the role of MEF2C in bone development and metabolism. During bone development, MEF2C promotes the development of neural crest cells (NC) into craniofacial cartilage and directly promotes cartilage hypertrophy. In terms of bone metabolism, MEF2C exhibits a differentiated regulatory model across different types of osteocytes, demonstrating both promoting and other potential regulatory effects on bone formation, with its stimulating effect on osteoclasts being determined. In view of the complex roles of MEF2C in bone tissue, this paper also discusses its effects on some bone diseases, providing valuable insights for the physiological study of bone tissue and strategies for the prevention of bone diseases.
Humans ; MEF2 Transcription Factors/physiology* ; Bone and Bones/metabolism* ; Animals ; Bone Development/physiology* ; Osteogenesis/physiology* ; Myogenic Regulatory Factors/physiology*

OBJECTIVE: To explore the clinical characteristics and genetic etiology for two children with Neurodevelopmental disorder with hypotonia, stereotypic hand movements, and impaired language (MEDHSIL). METHODS: Two children who had visited the Ningbo Women and Children's Hospital on October 15, 2021 were selected as the study subjects. Whole exome sequencing (WES) was carried out for both patients. Candidate variants were verified by Sanger sequencing of their family members. RESULTS: The two children were respectively found to harbor a heterozygous c.138delC (p.Ile47Serfs*42) variant and a c.833del (p.L278*) variant of the MEF2C gene. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), both variants were predicted to be pathogenic (PVS1+PS2+PM2_Supporting). CONCLUSION The c.138delC and c.833del variants of the MEF2C gene probably underlay the pathogenesis of MEDHSIL in the two children. Above findings have enriched the mutational spectrum of the MEF2C gene and enabled genetic counseling for their families.
Child ; Humans ; Family ; Genetic Counseling ; Language ; MEF2 Transcription Factors/genetics* ; Muscle Hypotonia/genetics* ; Neurodevelopmental Disorders

Animals ; Calcium-Calmodulin-Dependent Protein Kinase Type 2/metabolism* ; MEF2 Transcription Factors/metabolism* ; Muscle Fibers, Skeletal/metabolism* ; Muscle, Skeletal/metabolism* ; Myogenic Regulatory Factors/metabolism* ; Physical Conditioning, Animal/methods* ; Rats ; Signal Transduction

OBJECTIVE: To explore the genetic basis for a child with febrile seizures. METHODS: Peripheral venous blood samples were taken from the child and his parents for the analysis of chromosomal karyotype and dynamic variant of the FMR1 gene. The family trio was also subjected to target capture and next generation sequencing (NGS) with a gene panel related to developmental retardation, mental retardation, language retardation, epilepsy and special facial features. RESULTS: The child was found to have a normal karyotype by conventional cytogenetic analysis (400 bands). No abnormal expansion was found with the CGG repeats of the FMR1 gene. NGS revealed that the child has carried a heterozygous c.864+1 delG variant of the MEF2C gene, which may lead to abnormal splicing and affect its protein function. The same variant was found in neither parent, suggesting that it has a de novo origin. Based on the American College of Medical Genetics and Genomics standards and guidelines, c.864+1delG variant of MEF2C gene was predicted to be pathogenic (PVS1+PS2+PM2). CONCLUSION MEF2C, as the key gene for chromosome 5q14.3 deletion syndrome which was speculated as a cause for febrile seizures, has an autosomal dominant effect. The c.864+1delG variant of the MEF2C gene may account for the febrile seizures in this patient.
Child ; Chromosome Deletion ; Chromosome Disorders ; Epilepsy ; Fragile X Mental Retardation Protein ; Humans ; Intellectual Disability/genetics* ; Karyotyping ; MEF2 Transcription Factors/genetics*

BACKGROUND: Breast cancer treatment with selective estrogen receptor modulators (SERMs) increases the incidence of uterine malignant mixed Müllerian tumors (uMMMTs). We examine clinicopathologic characteristics and prognosis of SERM-associated uMMMTs (S-uMMMTs) and discuss possible pathogenetic mechanisms. METHODS: Among 28,104 patients with breast cancer, clinicopathologic features and incidence of uMMMT were compared between patients who underwent SERM treatment and those who did not. Of 92 uMMMT cases that occurred during the same period, incidence, dose, and duration of SERM treatment, as well as overall survival rate, were compared for patients with breast cancer who underwent SERM treatment and those who did not (S-uMMMT vs NS-uMMMT) and for patients without breast cancer (de novo-uMMMT). Histopathological findings and immunophenotypes for myogenin, desmin, p53, WT-1, estrogen receptor (ER) α, ERβ, progesterone receptor, and GATA-3 were compared between S-uMMMT and de novo-uMMMT. RESULTS: The incidence of S-uMMMT was significantly higher than that of NS-uMMMT (6.35-fold). All patients with SERM were postmenopausal and received daily 20–40 mg SERM. Cumulative SERM dose ranged from 21.9 to 73.0 g (mean, 46.0) over 39–192 months (mean, 107). Clinicopathologic features, such as International Federation of Gynecology and Obstetrics stage and overall survival, were not significantly different between patients with S-uMMMT and NS-uMMMT or between patients with S-uMMMT and de novo-uMMMT. All 11 S-uMMMT cases available for immunostaining exhibited strong overexpression/null expression of p53 protein and significantly increased ERβ expression in carcinomatous and sarcomatous components. CONCLUSIONS: SERM therapy seemingly increases risk of S-uMMMT development; however, clinicopathologic features were similar in all uMMMTs from different backgrounds. p53 mutation and increased ERβ expression might be involved in the etiology of S-uMMMT.
Breast Neoplasms ; Breast ; Desmin ; Estrogens ; Gynecology ; Humans ; Incidence ; Myogenin ; Obstetrics ; Prognosis ; Receptors, Progesterone ; Selective Estrogen Receptor Modulators ; Survival Rate ; Tamoxifen

OBJECTIVE: To investigate the effect of Xiaozhong Zhitong Ointment(XZZTO) on remodeling and repair of skeletal muscle injury in rats based on the expression mechanism of microRNA. METHODS: The rat gastrocnemius injury model was established by blunt contusion model. The expression of MEF2 gene and protein in gastrocnemius muscle was detected by quantitative PCR at 4, 7, 14 and 21 days after injury with XZZTO. The mechanism of the effect of XZZTO on the muscle remodeling and repair of rat gastrocnemius contusion model was discussed. RESULTS: The expression level of MEF2 in the treatment group was significantly higher than that of the control group and model group, which further confirmed the important role of MEF2 in inducing skeletal muscle remodeling and repair process in the topical drugs. The expression of MEF2 increased at 7 days after injury and remained at a high level until 21 days after injury. Compared with the model group, the peak expression period was about 14 days, and then returned to the general state. CONCLUSIONS The expression level of MEF2 shows an upward trend. Even 21 days after injury, the expression of MEF2 dose not show a significant downward trend. It can be seen that XZZTO can promote the expression of MEF2. At the same time, XZZTO can regulate the regeneration and repair of skeletal muscle. Therefore, XZZTO can play a regeneration and repair role after skeletal muscle injury through gene regulation.
Animals ; Contusions ; Gastrointestinal Tract ; Gene Expression Regulation ; MEF2 Transcription Factors ; genetics ; Muscle, Skeletal ; Ointments ; Proteins ; RNA, Messenger ; Rats

BACKGROUND: Primary breast sarcoma (PBS) is rare, comprising approximately 1% of breast malignancies. Rhabdomyosarcoma (RMS) accounts for an extremely small proportion of PBSs, often leading to delayed histologic confirmation. METHODS: Upon reviewing Asan Medical Center’s pathology database between 2000 and 2018, 41 PBS cases were retrieved, including three cases of primary RMS of the breast. Their clinicopathological features were analyzed, and the literature related to PBS and primary RMS of the breast was reviewed. RESULTS: We identified three primary breast RMS cases from our institution database, comprising 7.3% of PBS: one case each of spindle cell/sclerosing RMS (ssRMS), alveolar RMS (aRMS), and embryonal RMS (eRMS). All cases involved adolescents or young adults (14, 16, and 25 years, respectively) who underwent mastectomy or radiotherapy and were confirmed using immunohistochemical testing for myogenin, desmin, and myogenic differentiation. The ssRMS patient experienced recurrence at the operation site 4 months post-surgery despite undergoing concurrent chemoradiotherapy. The aRMS patient had multiple metastases at diagnosis and showed FAX3-FOXO1 fusion transcripts; she died 22 months after the diagnosis. The eRMS patient had enlarged axillary lymph nodes; post-radiotherapy, the lesion recurred as multiple metastases to the bone and lung. She died 18 months post-diagnosis. CONCLUSIONS: Our experience on RMS cases suggests that spindle cell or small round cell malignancy in breasts of young female should raise suspicion for the possibility of primary or secondary RMS. To our knowledge, this is the second report of primary breast ssRMS and it may help clinicians who encounter this rare disease in the future.
Adolescent ; Arm ; Breast ; Chemoradiotherapy ; Chungcheongnam-do ; Desmin ; Diagnosis ; Female ; Humans ; Lung ; Lymph Nodes ; Mastectomy ; Myogenin ; Neoplasm Metastasis ; Pathology ; Radiotherapy ; Rare Diseases ; Recurrence ; Rhabdomyosarcoma ; Sarcoma ; Young Adult

This paper reported a case of cervical intraspinal metastasis of alveolar rhabdomyosarcoma (ARMS). The clinicopathological features, surgical treatment, chemotherapy and prognosis were introduced and the current literature was reviewed. The diagnosis, differential diagnosis, treatment, molecular features and prognosis of the disease were comprehensively analyzed to improve clinicians' knowledge of this rare disease. The primary lesion appeared about 1 year ago which was painless mass of left hand whose size was about 2 cm×2 cm. After conservative treatment, the mass gradually enlarged and the mass was resected. Postoperative pathology revealed embryonic rhabdomyosarcoma. Postoperative chemotherapy with recombinant human endostatin, liposomal doxorubicin and ifosfamide was performed. The left neck mass was found about 3 months ago, and then the left neck mass was resected under general anesthesia. Postoperative pathological examination showed small round cell malignant tumors. Severe left upper extremity pain began about 2 weeks ago with nocturnal pain and supine pain. Non-steroidal anti-inflammatory drugs were needed to relieve pain which was accompanied by numbness and weakness of the left upper extremity. MRI showed a intraspinal tumor at C5. The left thumb and index finger were absent. Hypoesthesia, muscle atrophy and hypotonia of the left upper limb were confirmed. The muscle strength of biceps brachii and deltoid muscle of the left upper limb was grade 0, the muscle strength of extensor carpus and interphalangeal muscle was grade II, the muscle strength of intrinsic muscles of hands was grade I. The tendon reflex of the left upper limb disappeared. Intraspinal mass was removed and the pain was relieved. But there was no significant change in the muscle strength of the left upper limb. Pathological examination revealed small cell malignancies which were poorly differentiated with diffuse patchy distribution and disordered arrangement. The tumor cells had round, oval or irregular nuclei, and few cytoplasms were positive for Myogenin and MyoD1. FISH test of FOXO1 gene was positive. More than 50% of nuclei showed redgreen signal separation, and the distance between redgreen signals was larger than double diameter of the signal points, which supported ARMS. Total resection of intraspinal tumors was achieved and postoperative chemotherapy was admitted. But intraspinal disseminated metastasis occurred rapidly. ARMS was rare, aggressive tumor with poor prognosis. Subdural metastasis was rare. Correct diagnosis and classification can be made only with help of modern molecular diagnostic methods, which is effective to guide the treatment.
Humans ; Ifosfamide ; Muscle, Skeletal ; Myogenin ; Prognosis ; Rhabdomyosarcoma, Alveolar ; Spinal Neoplasms

OBJECTIVES: Rheumatoid arthritis (RA) is characterized by chronic inflammation of the synovium, progressive erosion of the articular cartilage, and joint destruction. RA also causes secondary osteoporosis and muscle wasting. We investigated the effects of ibandronate (IBN), a bisphosphonate; eldecalcitol (ELD), an active vitamin D3 derivative; and combination treatment with both agents on secondary osteoporosis and muscle wasting using adjuvant-induced arthritis rats. METHODS: Arthritis was induced in 8-week-old male Lewis rats. Rats were randomized into 4 treatment groups and an untreated normal control group: IBN (subcutaneously, once every 2 weeks, 10 µg/kg), ELD (orally, once daily, 30 ng/kg/day), IBN + ELD, vehicle, and control. Paw thickness measurements were performed for evaluation of arthritis. The femur was scanned using dual-energy X-ray absorptiometry. Cross-sectional areas of left tibialis and anterior muscle fibers and the expression of MuRF1, atrogin-1, MyoD, and myogenin in the gastrocnemius muscle were measured to evaluate muscle wasting. RESULTS: IBN and/or ELD increased bone mineral density (BMD) in the femur. In addition, there was an additive effect of combination treatment compared with single treatments for BMD. However, IBN and/or ELD did not inhibit muscle wasting in adjuvant-induced arthritis rats. CONCLUSIONS: Combination treatment with IBN and ELD may be effective for secondary osteoporosis associated with RA. Other treatments are necessary for muscle wasting associated with RA. Studies in humans are needed to confirm these findings.
Absorptiometry, Photon ; Animals ; Arthritis ; Arthritis, Rheumatoid ; Bone Density ; Cartilage, Articular ; Cholecalciferol ; Femur ; Humans ; Inflammation ; Joints ; Male ; Muscle, Skeletal ; Myogenin ; Osteoporosis ; Rats ; Synovial Membrane ; Vitamin D

Bone marrow-derived mesenchymal stem cells (BMSCs) for repairing damaged heart tissue are a new kind of important treatment options because of their potential to differentiate into cardiomyocytes. We in this experiment investigated the effect of different electrical stimulation time on the expression of myocardial specificity gene and protein in rat bone marrow mesenchymal stem cells (rBMSCs) in vitro. The rBMSCs of second or third generation were randomly divided into three groups, i.e, electrical stimulation (ES) group, 5-Azacytidine (5-Aza) group and the control group. The rBMSCs in the ES groups with complete medium were exposed to 2 V, 2 Hz, 5 ms electrical stimulation for 0. 5 h, 2 h, 4 h, and 6 h respectively every day for 10 days. Those in the 5-Aza group were induced by 5-Aza (10 μmol/L) for 24 h, and then cultured with complete medium for 10 days. Those in the control group were only cultured with complete medium, without any treatment, for 10 days. The rBMSCs' morphological feature in each group was observed with inverted phase microscope. The mRNA expression of myocyte-specific enhancer factor 2C (MEF-2C) and connexin 43 (Cx43) were examined with Real-Time quantitative PCR and the protein expression of MEF-2C, Cx43 were detected with Western Blot method. The results showed that the mRNA expression level of the MEF-2C, Cx43 and the protein expression level of MEF-2C, Cx43 were significantly higher in the ES group and 5-Aza group than those in the relative control group (P < 0.05). It suggests that electrical stimulation could play a part of role in the induction of the rBMSCs to differentiate into the cariomyocyte-like cells in vitro and the effectiveness of the electrical stimulation with 2 h/d had the best in our experiment. But the mechanism how electrical stimulation promotes the differentiation of rBMSC into cardiomyocyte is still unclear.
Animals ; Biomarkers ; metabolism ; Cell Differentiation ; Cells, Cultured ; Connexin 43 ; metabolism ; Electric Stimulation ; MEF2 Transcription Factors ; metabolism ; Mesenchymal Stromal Cells ; cytology ; metabolism ; Myocytes, Cardiac ; cytology ; RNA, Messenger ; metabolism ; Rats ; Rats, Sprague-Dawley