Centronuclear myopathy (CNM) is a rare congenital myopathy that is pathologically characterized by the centrally locatednuclei in most of the muscle fibers. On clinical examination, dynamin 2 (DNM2)-related CNM typically shows distaldominant muscle atrophy, ptosis, ophthalmoplegia, and contracture. The reported cases of CNM in Caucasian studies showa high prevalence rate of early-onset ptosis and ophthalmoplegia and correlated with the severity of the disease. However,Asian reports show a low prevalence and late-onset ocular symptoms in DNM2-related CNM patients. p.R465W is one ofthe most commonly found mutations in Western countries, and all the cases showed ocular symptoms. The proband and hisdaughter had no ocular symptoms despite harboring the same p.R465W mutation. This family makes us speculate that ocularsymptoms in DNM2-related CNM are influenced by ethnic background. In addition, this is the first familial case of DNM2-related CNM in Korea.
Contracture ; Dynamin II ; Dynamins* ; Humans ; Korea ; Muscular Atrophy ; Muscular Diseases ; Myopathies, Structural, Congenital* ; Ophthalmoplegia ; Prevalence

OBJECTIVE: To explore the clinical features and disease-causing variants of a pediatric patient with fatal encephalopathy caused by mitochondrial peroxidase division deficiency, to identify the possible genetic causes of the disease and provide a basis for clinical diagnosis. METHODS: A child with fatal encephalopathy caused by mitochondrial peroxidase division deficiency in West China Second Hospital of Sichuan University was selected. The clinical manifestations, laboratory findings and disease-causing variant were analyzed. RESULTS: The main clinical symptoms of the patient were fever, headache and vomiting, followed by drug refractory epilepsy and progressive disturbance of consciousness. MRI showed deepening of sulcus, dilatation of bilateral ventricles, and multiple patch-like abnormal signals in paraventricular white matter, semioval center and subcortical white matter of bilateral frontal lobe. Gene detection showed a heterozygous missense variant c.1207C>T(p.Arg403Cys) in DNM1L, according to the American College of Medical Genetics and Genomics classification standards and guidelines for genetic variants, this variant was predicted to be pathogenic(PS1+PS2+PM2+PP3). After treated with gamma globulin, glucocorticoid, "mitochondrial cocktail therapy" and anti-epilepsy drugs, the condition of the patient was getting better, seizure attacks reduced and consciousness level improved. CONCLUSION The c.1207C>T variant in DNM1L gene may be the disease-causing variant for the patient, and the result of genetic testing provides a basis for the clinical diagnosis in this case.
Child ; Drug Resistant Epilepsy ; Dynamins ; Genomics ; Humans ; Mitochondria ; Mutation ; Peroxidase ; Seizures

OBJECTIVETo investigate the expression of Dynamin subtypes in inner hair cell (IHC) of mice, and to discuss their possible roles in age-related hearing loss.

METHODSAuditory brainstem response (ABR) was recorded from the Kunming mice on postnatal 3 weeks (young), 10 weeks (adult), and 16 months (aged), 10 mice in each group. The expression of each Dynamin isoforms in the hair cells of the cochlea was observed by immunofluorescence staining and confocal microscope, and the transcription level of Dynamin subtypes mRNA was detected in qRT-PCR. Data analysis using SPSS 18 software.

RESULTSABR threshold showed no significant difference between the group of young and adult (t = -5.273, P = 0.076), but the threshold of the aged group increased comparing with young group (t = -8.365, P = 0.000), and adult group (t = -6.191, P = 0.000). All subtypes expressed in the inner hair cell of mice, of which Dynamin-1 and 2 expressed in the whole inner hair cell in the group of young and adult. In the aged group, Dynamin-1 was lost beneath the nucleus, and Dynamin-2 only be found near the nucleus. In addition, Dynamin-3 was scattered in the region of the basal part of the cells beneath the nucleus and near the spiral ganglion. The qRT-PCR revealed that mRNA of Dynamin-1 reduced with age (F = 10.410, P = 0.011), mRNA of Dynamin-2 increased to a peak in the adult group and then reduced with age (F = 24.575, P = 0.000). Meanwhile, mRNA of Dynamin-3 was not be detected.

CONCLUSIONSAll subtypes of Dynamin express in IHC. The expression of Dynamin-1 and 2 is up-regulated during maturity, which might alter the endocytosis of IHC; and the disorder of endocytosis might modulate the synaptic transmission of IHC. Whether Dynamin-3 plays a role in inner hair cells remains unclear because of the low expression.

Aging ; metabolism ; Animals ; Cochlea ; metabolism ; Dynamins ; metabolism ; Evoked Potentials, Auditory, Brain Stem ; Hair Cells, Auditory, Inner ; metabolism ; Mice

As the basic physiological function of synapses, vesicle cycling involves in many aspects of process. Among them, vesicle recycling is the basis of synaptic vesicle cycling. Studies show that clathrin mediated endocytosis is a major pathway of vesicle recycling, in which Dynamin plays an important role. Dynamin is a GTPases with molecular weight of 100 kD, which acts as "scissors" in the endocytosis, separating the clathrin coated pits from membrane. It has been found that Dynamin is associated with epilepsy, Alzheimer's disease, centronuclear myopathy, and several other neurological diseases. In this paper, we discussed the structure, function and regulation of Dynamin, and reviewed recent advance in the studies on Dynamin related diseases.
Clathrin ; physiology ; Coated Pits, Cell-Membrane ; physiology ; Dynamins ; physiology ; Endocytosis ; Humans ; Synapses ; physiology ; Synaptic Transmission ; Synaptic Vesicles ; physiology

Mitochondrial functions are essential for the survival and function of neurons. Recently, it has been demonstrated that mitochondrial functions are highly associated with mitochondrial morphology, which is dynamically changed by the balance between fusion and fission. Mitochondrial morphology is primarily controlled by the activation of dynamin-related proteins including dynamin-related protein 1 (Drp1), which promotes mitochondrial fission. Drp1 activity is regulated by several post-translational modifications, thereby modifying mitochondrial morphology. Here, we found that phosphorylation of Drp1 at serine 616 (S616) is mediated by cyclin-dependent kinase 5 (CDK5) in post-mitotic rat neurons. Perturbation of CDK5 activity modified the level of Drp1S616 phosphorylation and mitochondrial morphology in neurons. In addition, phosphorylated Drp1S616 preferentially localized as a cytosolic monomer compared with total Drp1. Furthermore, roscovitine, a chemical inhibitor of CDKs, increased oligomerization and mitochondrial translocation of Drp1, suggesting that CDK5-dependent phosphorylation of Drp1 serves to reduce Drp1's fission-promoting activity. Taken together, we propose that CDK5 has a significant role in the regulation of mitochondrial morphology via inhibitory phosphorylation of Drp1S616 in post-mitotic neurons.
Animals ; Cells, Cultured ; Cyclin-Dependent Kinase 5/*metabolism ; Dynamins/analysis/*metabolism ; HeLa Cells ; Humans ; Mitochondria/metabolism ; Mitosis ; Neurons/*cytology/*metabolism ; Phosphorylation ; Rats

OBJECTIVETo detect the levels of miR-499 and relative proteins in hearts of mice after exercise training, and investigate the mechanism of exercise-regulative apoptosis.

METHODSMale C57BL/6 mice were randomly divided into 3 groups( n = 14): sedentary (SE), exercise training 1 (ET1) and exercise training 2 (ET2) group. SE did not do any exercise. ET1 performed swimming training for 8 weeks. ET2 performed the same work as ET1 until the 5th week. Then, mice trained twice a day until the end of training. TUNEL assay was applied to test myocardial apoptosis, RT-PCR and Western blot were used to detect miR-499 and proteins levels respectively.

RESULTSCompared with SE, stress in ET1 failed to affect apoptotic index (AI) and miR-499-CaN-Drp-1 pathway (P > 0.05). In contrast, exercise load in ET2 increased miR-499 level, decreased Drp-1 level and AI with statistical significance respectively (P < 0.05), but neither CaN expression nor CaN activity was changed significantly (P > 0.05).

CONCLUSIONSwimming training can inhibit myocardial apoptosis, and the decrease in Drp-l may be responsible for the reduced myocardial apoptosis. CaN, the upstream protein, does not participate in exercise-regulative apoptosis.

Animals ; Apoptosis ; Dynamins ; metabolism ; Heart ; Male ; Mice ; Mice, Inbred C57BL ; MicroRNAs ; metabolism ; Mitochondria, Heart ; physiology ; Myocardium ; pathology ; Physical Conditioning, Animal ; Swimming

OBJECTIVETo explore the changes of protein expression of mitochondrial fission gene dynamin-related 1(Drp 1) in the cortical neurons of rats with chronic fluorosis.

METHODSA total of 120 one-month-old SD rats (each weighing approximately 100-120 g at the beginning of the experiment) were randomly divided into three groups, and fed with the different doses of fluoride containing in drinking water (untreated control containing 0 mg/L fluoride, and low-fluoride & high-fluoride supplemented with 10 and 50 mg/L fluoride,respectively). After 3 or 6 months exposure, 20 rats from each group were killed. Then the protein expression of mitochondrial fission gene, Drp1, was detected by immunohistochemistry and western-blotting method.

RESULTSDental fluorosis and urinary fluorosis were obviously found in the rats exposed to fluoride. At the experiment period of 3 months, the numbers of positive cells of Drp1 detected by immunohistochemistry changed. Compared with the control group (36.3 ± 5.8), the changes in low-fluoride group (34.7 ± 4.1) showed no significant difference (t = 1.5, P > 0.05),but the increase in high-fluoride group (45.0 ± 4.7) had statistical significance (t = 8.8, P < 0.05). The western-blotting method had consistent results. Compared with the control group (0.59 ± 0.03), a significant increase of the average topical density in low- fluoride (0.62 ± 0.03) and high-fluoride (0.71 ± 0.02) groups were found (t = 0.02,0.11, P < 0.05). At the experiment period of 6 months, the numbers of positive cells of Drp1 detected by immunohistochemistry significantly changed. Compared with the control group (33.2 ± 4.4), the number in low- fluoride and high-fluoride groups were separately (36.6 ± 3.8) and (39.4 ± 4.2),both increased significantly (t = 3.5,6.3, P < 0.05). Same results could be found in western-blotting method,compared with the control group (0.65 ± 0.06), the average topical density in low- fluoride (0.80 ± 0.09) and high-fluoride (0.76 ± 0.08) groups both increased significantly (t = 0.1,0.1, P < 0.05).

CONCLUSIONSTaking excessive amount of fluoride might result in the changes of expression of Drp1, and the neurons damage from the chronic fluorosis might be associated with the hyperfunction of mitochondrial fusion.

Animals ; Drinking Water ; chemistry ; Dynamins ; genetics ; metabolism ; Fluoride Poisoning ; metabolism ; Fluorides ; urine ; Fluorosis, Dental ; metabolism ; Male ; Mitochondrial Dynamics ; Neurons ; metabolism ; pathology ; Rats ; Rats, Sprague-Dawley

The aim of this study was to investigate the effect of edaravone (Eda) on the balance of mitochondrial fusion and fission in Parkinson's disease (PD) cell model. A cell model of PD was established by treating PC12 cells with 500 μmol/L 1-methyl-4-phenylpyridinium (MPP). Thiazole blue colorimetry (MTT) was used to detect the effect of different concentrations of Eda on the survival rate of PC12 cells exposed to MPP. The mitochondrial morphology was determined by laser confocal microscope. Western blot was used to measure the protein expression levels of mitochondrial fusion- and fission-related proteins, including OPA1, MFN2, DRP1 and Fis1. The results showed that pretreatment with different concentrations of Eda antagonized MPP-induced PC12 cell damage in a dose-dependent manner. The PC12 cells treated with MPP showed mitochondrial fragmentation, up-regulated DRP1 and Fis1 protein expression levels, and down-regulated MFN2 and OPA1 protein expression levels. Eda could reverse the above changes in the MPP-treated PC12 cells, but did not affect Fis1 protein expression. These results suggest that Eda has a protective effect on the mitochondrial fusion disruption induced by MPP in PC12 cells. The mechanism may be related to the up-regulation of OPA1/MFN2 and down-regulation of DRP1.
1-Methyl-4-phenylpyridinium ; Animals ; Dynamins ; Edaravone ; pharmacology ; GTP Phosphohydrolases ; Mitochondria ; drug effects ; Mitochondrial Dynamics ; Mitochondrial Proteins ; PC12 Cells ; Parkinson Disease ; Rats ; Up-Regulation

Viperin is an IFN-stimulated gene (ISG)-encoded protein that was identified in human primary macrophages treated with IFN-γ and in human primary fibroblasts infected with cytomegalovirus (CMV). This protein plays multiple roles in various cell types. It inhibits viral replication, mediates signaling pathways, and regulates cellular metabolism. Recent studies have shown that viperin inhibits IFN expression in macrophages, while it enhances TLR7 and TLR9-mediated IFN production in plasmacytoid dendritic cells, suggesting that viperin can play different roles in activation of the same pathway in different cell types. Viperin also controls induction of ISGs in macrophages. However, the effect of viperin on induction of ISGs in cell types other than macrophages is unknown. Here, we show that viperin differentially induces ISGs in 2 distinct cell types, macrophages and fibroblasts isolated from wild type and viperin knockout mice. Unlike in bone marrow-derived macrophages (BMDMs), viperin downregulates the expression levels of ISGs such as bone marrow stromal cell antigen-2, Isg15, Isg54, myxovirus resistance dynamin like GTPase 2, and guanylate binding protein 2 in murine embryonic fibroblasts (MEFs) treated with type I or II IFN. However, viperin upregulates expression of these ISGs in both BMDMs and MEFs stimulated with polyinosinic-polycytidylic acid or CpG DNA and infected with murine CMV. The efficiency of viral entry is inversely proportional to the expression levels of ISGs in both cell types. The data indicate that viperin differentially regulates induction of ISGs in a cell type-dependent manner, which might provide different innate immune responses in distinct cell types against infections.
Animals ; Carrier Proteins ; Cytomegalovirus ; Dendritic Cells ; DNA ; Dynamins ; Fibroblasts ; GTP Phosphohydrolases ; Humans ; Immunity, Innate ; Interferons ; Macrophages ; Mesenchymal Stromal Cells ; Metabolism ; Mice ; Mice, Knockout ; Orthomyxoviridae ; Poly I-C

Nitric oxide synthases (NOSs) play complex roles in the regulation of cardiac excitation contraction coupling under basal and stressed conditions. Herein, using the recording approach for intracellular calcium transient and synchronous myocyte contraction, the potential mechanism for NOSs-mediated cardiomyocyte contraction was explored. We found that selective inhibition of neuronal NOS (nNOS) with 100 µmol/L spermidine markedly enhanced the cardiomyocyte twitch [control: (10.5 ± 0.21)%; nNOS inhibition: (12.4 ± 0.18)%] and calcium transient [control: (0.27 ± 0.03)%; nNOS inhibition: (0.42 ± 0.01)%], but slowed the relengthening of twitch [control: (25.2 ± 1.3) ms; nNOS inhibition: (53 ± 2.8) ms] and the calcium transient decay [control: (129 ± 4.3) ms; nNOS inhibition: (176 ± 7.1) ms], which was similar to that by dynamin inhibition with 30 µmol/L dynasore. The nNOS inhibition- or dynasore-mediated effects could be rescued by an NO donor, S-Nitroso-N-acetylpenicillamine (SNAP). Our data suggest that the selective nNOS-mediated regulation of cardiac contractile activity may partly involve the dynamin-mediated endocytic mechanism.
Animals ; Biological Transport ; Calcium Signaling ; Dynamins ; antagonists & inhibitors ; physiology ; Endocytosis ; physiology ; Female ; Hydrazones ; pharmacology ; Male ; Myocardial Contraction ; physiology ; Nitric Oxide Synthase Type I ; physiology ; Rats ; Rats, Sprague-Dawley ; Spermidine ; pharmacology ; Transport Vesicles ; physiology