Objective To investigate the major types and clinical manifestations of mitochondrial DNA (mtDNA)mutations in Chinese patients with Leber′s hereditary optic neuropathy(LHON). Methods A total of 119 patients with bilateral optic neuropathy from 117 pedigrees, including 37 with determinate diagnosis of LHON(group A) and 82 with suspected LHON(group B),were tested for mtDNA mutations by using single-strand conformational polymorphism, mutation-specific primer polymerase chain reaction and sequencing. Pertinent clinical data and history of the patients with the 11778 mutation were collected. Results Nucleotide positions(np)11778 mutation and np 14484 mutation was found in 33 (89.2%) and 3 (8.1%) patients respectively in group A, while np 11778 mutation was obtained in 26（31.7%）in group B. No 3460 mutation was found in group A or B. The clinical manifestations of 59 patients with np 11778 mutation were as follows: acute or chronic visual loss，no ophthalmalgia, the age of onset of 10-25, and either a central or paracentral scotoma in perimetry. The visual recovery rate was 8.6%～11.6%. Conclusion Chinese patients with LHON have a very high incidence of np 11778 mutation and the clinical manifestations of the patients with np 11778 mutation are similar to those of Caucasian patients. (Chin J Ocul Fundus Dis，2004，20：78-80)
Purpose
To investigate mitochondrial DNA (mt-DNA) mutations in optic neuritis of unknow reason (ONUR) and to assess the pathogenic and differential diagnostic values of screening for mt-DNA mutations in ONUR.
Method
Thirty patients with ONUR were screened for mt-DNA mutations by using SSCP,mutation-specific primer PCR and sequencing.
Results
mt-DNA mutations were found in 12 out of the thirty patients.All of the mutations were at 11778 position,but no one at 3460 and 15257.
Conclusions
Quite a number of patients (12/30,40%) with ONUR were caused actually by mt-DNA mutation．Screening for mt-DNA mutation in these patients has a pathogenic and differential diagnostic significance.
(Chin J Ocul Fundus Dis,2000,16:78-79)
ObjectiveTo explore the effects and molecular mechanisms of histone methylase G9a inhibitor BIX-01294 on apoptosis in esophageal squamous cell carcinoma (ESCC).MethodsMTT assay and Colony-forming Units were adopted to determine the effects of BIX-01294 on the growth and proliferation of ESCC cell lines EC109 and KYSE150. Flow cytometry was used to analyze the apoptosis status of ESCC cells after the treatment of BIX-01294. The effects of BIX-01294 treatment on the expressions of G9a catalytic product H3K9me2, DNA double-strand break (DSB) markers, and apoptosis-related proteins were detected by Western blotting.ResultsBIX-01294 inhibited the growth of EC109 and KYSE150 cells in a dose-dependent manner (P<0.05), and BIX-01294 with the inhibitory concentration 50% (IC50) significantly inhibited the formation of colony (P<0.05). After 24 hours treatment of BIX-01294 (IC50), the apoptosis rate of EC109 cells increased from 11.5%±2.1% to 42.5%±5.4%, and KYSE150 cells from 7.5%±0.9% to 49.2%±5.2% (P<0.05). The expression level of the G9a catalytic product, H3K9me2, significantly decreased (P<0.05); while the expression of the DSB marker γH2AX was dramatically enhanced (P<0.05). We also found that the mitochondrial apoptosis pathway was activated and the expression levels of cleaved caspase3 and cleaved PARP were significantly elevated (P<0.05).ConclusionBIX-01294, the inhibitor of methyltransferase G9a, prompted apoptosis in ESCC cells by inducing DSB damage and activating mitochondrial apoptosis pathway.
ObjectiveTo observe the clinical features of patients over 30 years old with Leber hereditary optic neuropathy (LHON).
MethodsNine male LHON patients (18 eyes) were enrolled in this study. The patients aged from 34 to 56 years old, with an average age of (45.22±6.91) years. The course of the disease ranged from 7 days to 21 months, with a mean course of 5 months. Visual acuity, slit lamp microscope, chromoptometry, direct ophthalmoscope and fundus photography were measured for all patients, visual field examined for 6 patients (11 eyes). Mitochondrial DNA mutation was analyzed. The visual acuity was followed-up for 12 months.
ResultsSeven of the 9 patients (77.78%) had family history. Five patients (55.56%) had both eyes involved simultaneously, and 4 patients (44.44%) had the eyes involved at different time. Three patients (33.33%) had sudden visual loss, and 6 patients (66.67%) had gradual visual loss. The visual acuity was light perception in 1 eye (5.55%), finger counting in 3 eyes (16.67%), 0.01-0.1 in 7 eyes (38.89%), 0.12-0.3 in 3 eyes (16.67%), equal or greater than 0.4 in 4 eyes (22.22%). Sixteen eyes (88.88%) had normal light reflex, 1 eye (5.55%) had no light reflex, and 1 eye (5.55%) had relative afferent papillary defect. Eight eyes (44.44%) had normal optic disk, 3 eyes (16.67%) had blurred optic disc border and disc telangiectasia, 7 eyes (38.89%) had pale disc and clear boundary. Among 11 eyes underwent visual field examination, 9 eyes (81.82%) had central or paracentral scotoma and 2 eyes (18.18%) had visual field narrowing. Among 9 patients, there were 7 patients (77.78%) with G11778A mutation, 1 patient (11.11%) with G11696A mutation, and 1 patient (11.11%) with T14484C mutation. In the last follow-up, the visual acuity was light perception in 1 eye (5.55%), finger counting in 4 eyes (22.22%), 0.01-0.1 in 6 eyes (33.33%), 0.12-0.3 in 3 eyes (16.67%), equal or greater than 0.4 in 4 eyes (22.22%).The visual acuity was improved in 9 eyes (50.00%), stable in 7 eyes(38.89%), and decreased in 2 eyes (11.11%).
ConclusionLHON patients (older than 30 years) are more common in men, mostly with normal light reflex, central or paracentral scotoma and G11778A mutation.
Objective To investigate the effect of mitochondrial fission mediated by mitochondrial dynamics related protein 1 (DRP1) on glucose metabolism reprogramming in lung cancer cells, and the regulatory mechanism on phosphatidylinositol-3-kinases (PI3K)/protein kinase B (Akt) signaling pathway. Methods Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) was used to detect the mRNA expression of DRP1 in lung cancer tissue and lung cancer cells. Mitochondrial fission inhibitor (Mdivi-1) and Mdivi-1+PI3K/Akt signaling pathway activator 740Y-P were used to treat H1299 cells. Mitochondrial fission agonist (WY14643) + signal inhibitor LY294002 were used to intervene PC14 cells. The reagent kit was used to detect the glucose consumption, lactate release, and ATP production of each group of cells. 5-ethynyl-2-deoxyuridine (EdU) labeling experiment was used to detect the proliferation of cells in each group, and acridine orange/ethidium bromide (AO/EB) staining was used to detect the apoptosis of cells in each group. MitoTracker Red CMXRos was used to detect the mitochondrial morphology of each group of cells. Tetramethylrhodamine ethyl ester (TMRE) staining was used to detect the mitochondrial membrane potential of cells. Dihydroethidium (DHE) staining was used to detect the level of reactive oxygen species (ROS) in cells. Western blot was used to detect was used to detect the expression of pyruvate kinase M2 (PKM2), hexokinase 2 (HK2), phosphofructokinase-1 (PFK1), DRP1, phosphorylated DRP1 (p-DRP1), PI3K, Akt, phosphorylated PI3K (p-PI3K), and phosphorylated Ak t(p-Akt) in each group of cells. Results The mRNA expression of DRP1 was significantly increased in lung cancer tissue and lung cancer cells. Mdivi-1 promoted the development of lung cancer and exerts anticancer effects, while activating PI3K/Akt signaling could partially reverse the anticancer effects of Mdivi-1. WY14643 exerted a pro-cancer effect, and inhibiting PI3K/Akt signaling could partially reverse the pro-cancer effect of WY14643, and the differences were statistically significant (all P<0.05). Conclusions In lung cancer, the expression of DRP1 is significantly increased, and DRP1 affects the glycolysis process and proliferation performance of lung cancer cells by regulating the activation of PI3K/Akt signaling.
As the “power center” of the cell and the center of metabolic signaling, mitochondria play an important role before, during, and after cerebral ischemia. After ischemic stroke, molecules such as mitoNEET, optic atrophy 1, and mitochondrial division inhibitor 1 can play a neuroprotective role by regulating the state of the mitochondria. Mitochondria are not only energy-supplying organelles, but their biogenesis and movement also play an important role in neuronal growth, differentiation, synapse formation and neural circuit formation after ischemic stroke. Rehabilitation at all stages can play a therapeutic role by modulating mitochondrial function.
Objective To review the research progress of mitochondrial dynamics mediated by optic atrophy 1 (OPA1) in skeletal system diseases. MethodsThe 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.
Objective To observe the oxidative damage of mtDNA, apoptosis and expression of adhesion molecules in retinal capillary cells of diabetic rat with different disease courses. Methods One hundred Sprague-Dawley rats were randomly divided into the control group and the experimental group. The rats of experimental group were induced with streptozotocin (STZ) injection creating a diabetic model. Then they were divided into DR1m, DR2m DR3m group according to disease courses. The rats of control group were divided into NR1m, NR2m, NR3m group. Rat retinal capillaries were prepared, and then the contents of undamaged mtDNA were examined by Southern blot combined with Fpg. The expression of cyclooxygenase (COX)-1 encoded by mtDNA and transcription factors A (mtTFA) mRNA were detected by real-time quantitative polymerase chain reaction (RT-PCR). Apoptosis and expression of intercellular adhesion molecule-1 (ICAM-1) were detected by terminal dUT nick endlabeling (TUNEL) immuno-fluorescence and immunohistochemistry respectively. Results The contents of undamaged mtDNA in rats of DR1m, DR2m, DR3m were less than those of NR1m、NR2m、NR3m. The contents of undamaged mtDNA in diabetic rats decreased with the increase of disease courses. In addition, the mRNA levels of COX-1 and mtTFA were downregulated in diabetic rats. The positive cells of TUNEL and ICAM-1TUNEL and ICAM-1 in diabetic rats increased with the increase of disease courses. Conclusion With the increase of disease courses, mtDNA damage and apoptotic cells are increased, while the expression of mRNA encoded by mtDNA and ICAM-1 decreased in retinal capillary cells in diabetic rats.
Lung cancer is the leading cause of cancer-related deaths worldwide. Despite the development and use of several targeting drugs for lung cancer therapy, the five-year survival rate has remained as low as 15% for the past three decades. Cisplatin-based chemotherapy is considered the first-line therapeutic strategy for lung cancer. However, developments of chemoresistance is a major obstacle for the successful treatment. Therefore, the development of novel therapy against cisplatin-resistance lung cancer is imperative. Photodynamic therapy (PDT), which is a non-invasive combinatorial therapeutic modality using light, photosensitizer (PS) and oxygen, may provide an unprecedented tool to develop more effective treatments. To provide experimental basis for its application in cisplatin-resistance lung cancer, we will discuss the biological effects of MPPa-photodynamic therapy in human cisplatin-resistance lung cancer cells in this article. Human cisplatin-resistance lung cancer cells A549/DDP were co-cultured with MPPa (0, 1, 2, 4, 8, 16 μmol/L) and exposed to light (0, 0.6, 1.2, 2.4, 3.6, 4.8 J/cm2), and cell viability was determined with CCK-8 assay. Flow cytometry was used to detect apoptosis, DCFH-DA staining was employed to observe reactive oxygen species (ROS), and Western blot was used to detect the expressions of B-cell lymphoma-2 (Bcl-2) protein and Bcl-2 associated X protein (Bax). The proliferation of A549/DDP cells was suppressed by PDT. The apop-totic rate in the PDT group was significantly higher than that in the control, MPPa or light group (P < 0.05). The level of ROS was increased. The expression of Bax was increased, and that of Bcl-2 was decreased. MPPa-photodynamic therapy can significantly suppress cell viability, and induce apoptosis in human cisplatin-resistance lung cancer cells.
