OBJECTIVE: To review the research progress of mitochondrial dynamics mediated by optic atrophy 1 (OPA1) in skeletal system diseases. METHODS: The literatures about OPA1-mediated mitochondrial dynamics in recent years were reviewed, and the bioactive ingredients and drugs for the treatment of skeletal system diseases were summarized, which provided a new idea for the treatment of osteoarthritis. RESULTS: OPA1 is a key factor involved in mitochondrial dynamics and energetics and in maintaining the stability of the mitochondrial genome. Accumulating evidence indicates that OPA1-mediated mitochondrial dynamics plays an important role in the regulation of skeletal system diseases such as osteoarthritis, osteoporosis, and osteosarcoma. CONCLUSION OPA1-mediated mitochondrial dynamics provides an important theoretical basis for the prevention and treatment of skeletal system diseases.
Humans ; GTP Phosphohydrolases/genetics* ; Mitochondrial Dynamics ; Osteoarthritis ; Osteoporosis

Objective This study aimed to assess the protective value of adiponectin (APN) in pancreatic islet injury induced by chronic intermittent hypoxia (CIH). Methods Sixty rats were randomly divided into three groups: normal control (NC) group, CIH group, and CIH with APN supplement (CIH+APN) group. After 5 weeks of CIH exposure, we conducted oral glucose tolerance tests (OGTT) and insulin released test (IRT), examined and compared the adenosine triphosphate (ATP) levels, mitochondrial membrane potential (MMP) levels, reactive oxygen species (ROS) levels, enzymes gene expression levels of
Adiponectin/genetics* ; Animals ; Hypoxia ; Islets of Langerhans ; Mitochondrial Dynamics ; Rats ; Rats, Wistar

Mitochondrial morphology is dynamically regulated by forming small, fragmented units or interconnected networks, and this is a pivotal process that is used to maintain mitochondrial homeostasis. Although dysregulation of mitochondrial dynamics is related to the pathogenesis of several human diseases, its molecular mechanism is not fully elucidated. In this study, we demonstrate the potential role of miR-27 in the regulation of mitochondrial dynamics. Mitochondrial fission factor (MFF) mRNA is a direct target of miR-27, whose ectopic expression decreases MFF expression through binding to its 3'-untranslated region. Expression of miR-27 results in the elongation of mitochondria as well as an increased mitochondrial membrane potential and mitochondrial ATP level. Our results suggest that miR-27 is a novel regulator affecting morphological mitochondrial changes by targeting MFF.
3' Untranslated Regions ; Cell Line ; Gene Expression Regulation ; Humans ; Membrane Potential, Mitochondrial ; Membrane Proteins/*genetics ; MicroRNAs/*metabolism ; Mitochondria/*genetics/*metabolism ; *Mitochondrial Dynamics ; Mitochondrial Proteins/*genetics ; *Protein Biosynthesis ; RNA, Messenger/genetics/metabolism

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

Objective To explore the effect of knocking down Rho-associated coiled-coil kinase (ROCK2) gene on the cognitive function of amyloid precursor protein/presenilin-1 (APP/PS1) double transgenic mice and its mechanism. Methods APP/PS1 double transgenic mice were randomly divided into AD model group (AD group), ROCK2 gene knock-down group (shROCK2 group), ROCK2 gene knock-down control group (shNCgroup), and wild-type C57BL/6 mice of the same age served as the wild-type control (WT group). Morris water maze and Y maze were employed to test the cognitive function of mice. Neuron morphology was detected by Nissl staining. Immunofluorescence histochemical staining was used to detect the expression of phosphorylated dynamin-related protein 1 (p-Drp1) and mitochondrial fusion 1 (Mfn1). Western blot analysis was used to detect the expression ROCK2, cleaved-caspase-3 (c-caspase-3), B-cell lymphoma 2 (Bcl2), Bcl2-related protein X (BAX), p-Drp1, mitochondrial fission 1 (Fis1), optic atrophy 1 (OPA1), Mfn1 and Mfn2. Results Compared with AD group mice, the expression of ROCK2 in shROCK2 group mice was significantly reduced; the cognitive function was significantly improved with the number of neurons in the hippocampal CA3 and DG areas increasing, and nissl bodies were deeply stained; the expression of c-caspase-3 and BAX was decreased, while the expression of Bcl2 was increased; the expression of mitochondrial division related proteins p-Drp1 and Fis1 were decreased, while the expression of mitochondrial fusion-related proteins OPA1, Mfn1 and Mfn2 were increased. Conclusion Knock-down of ROCK2 gene can significantly improve the cognitive function and inhibit the apoptosis of nerve cells of APP/PS1 mice. The mechanism may be related to promoting mitochondrial fusion and inhibiting its division.
Animals ; Mice ; Alzheimer Disease/pathology* ; Amyloid beta-Peptides/metabolism* ; Amyloid beta-Protein Precursor ; Apoptosis/genetics* ; bcl-2-Associated X Protein ; Caspase 3 ; Cognition ; Disease Models, Animal ; Mice, Inbred C57BL ; Mice, Transgenic ; Mitochondrial Dynamics/genetics*

OBJECTIVETo investigate the changes of mitochondrial distribution in axon/soma and the expression of mitochondrial fission 1 (Fis1) protein in the cortical neurons of rats with chronic fluorosis.

METHODSSixty SD rats were divided into 3 groups (20 each) according to weight hierarchy and fed with different concentrations of fluoride in drinking water (0, 10 and 50 mg/L, respectively) for 6 months. Images of mitochondria and tubulin labeled by immunofluorescence COXIV and tubulin-α were captured with fluorescence microscope. Fis1 protein expression in cortical neurons was analyzed with immunohistochemistry and Western blot. The expression of Fis1 mRNA was detected with real-time PCR.

RESULTSVarying degrees of dental fluorosis and increased fluoride contents in urine were observed in the rats receiving additional fluoride in drinking water. In the cortical neurons of rats fed with 10 mg/L and 50 mg/L fluoride, the numbers of neuronal soma stained with COXIV(34.8 ± 4.7 and 39.3 ± 3.0, respectively), and the expression of Fis1 protein (immunohistochemistry: 54.0 ± 3.6 and 51.3 ± 4.1, respectively; Western blot: 2.9 ± 0.4 and 2.6 ± 0.6, respectively) and mRNA (3773 ± 1292 and 1274 ± 162, respectively) was markedly increased as compared with controls (4.4 ± 2.3, 25.2 ± 2.5, 1.8 ± 0.2 and 277 ± 73) over the experimental period of 6 months.

CONCLUSIONSExcessive intake of fluoride results in an altered mitochondrial distribution in axon and soma in cortical neurons (i.e., the increase in soma and the decrease in axon), increased expression of Fis1 gene and enhanced mitochondrial fission. The altered mitochondrial distribution may be related to the high expression level of Fis1 and a functional disorder of mitochondria.

Animals ; Axons ; pathology ; Cerebral Cortex ; metabolism ; Drinking Water ; adverse effects ; chemistry ; Electron Transport Complex IV ; metabolism ; Female ; Fluorides ; adverse effects ; urine ; Fluorosis, Dental ; etiology ; metabolism ; pathology ; Male ; Mitochondria ; pathology ; Mitochondrial Dynamics ; drug effects ; Mitochondrial Proteins ; genetics ; metabolism ; Neurons ; metabolism ; RNA, Messenger ; metabolism ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Tubulin ; metabolism

Autophagy dysregulation, mitochondrial dynamic abnormality and cell cycle re-entry are implicated in the vulnerable neurons of patients with Alzheimer's disease. This study was designed to testify the association among autophagy, mitochondrial dynamics and cell cycle in dividing neuroblastoma (N2a) cells. The N2a cells were cultured in vitro and treated with different concentrations of 3-methyladenine (3-MA). The cell viability was detected by methyl thiazolyl tetrazolium (MTT) assay. They were randomly divided into control group (cells cultured in normal culture medium) and 3-MA group (cells treated with 10 mmol/L 3-MA). The cell cycle was analyzed in the two groups 3, 6, 12, and 24 h after treatment by flow cytometry. Western blotting was used to evaluate the expression levels of mitofission 1 (Fis1), mitofusin 2 (Mfn2), microtubule-associated protein 1 light chain 3 (LC3), cell cycle-dependent kinase 4 (CDK4) and cdc2. The flow cytometry revealed that the proportion of cells in G(2)/M was significantly increased, and that in G0/G1 was significantly reduced in the 3-MA group as compared with the control group. Western blotting showed that the expression levels of Fis1, LC3, and CDK4 were significantly up-regulated in the 3-MA group at the four indicated time points as compared with the control group. Mfn2 was initially decreased in the 3-MA group, and then significantly increased at 6 h or 12 h. Cdc2 was significantly increased in the 3-MA group at 3 h and 6 h, and then dropped significantly at 12 h and 24 h. Our data indicated that 3-MA-induced suppressed autophagy may interfere with the cell cycle progression and mitochondrial dynamics, and cause cell death. There are interactions among cell cycle, mitochondrial dynamics and autophagy in neurons.
Adenine ; administration & dosage ; analogs & derivatives ; Apoptosis ; drug effects ; Autophagy ; drug effects ; genetics ; CDC2 Protein Kinase ; Cell Cycle ; drug effects ; genetics ; Cell Division ; drug effects ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Cell Survival ; drug effects ; Cyclin B ; biosynthesis ; Cyclin-Dependent Kinases ; Gene Expression Regulation ; drug effects ; Humans ; Membrane Proteins ; biosynthesis ; Microtubule-Associated Proteins ; biosynthesis ; Mitochondrial Dynamics ; drug effects ; genetics ; Mitochondrial Proteins ; biosynthesis ; Neuroblastoma ; Signal Transduction ; drug effects