ObjectiveTo elucidate the metabolic characteristics of mitochondria in sepsis and review its cellular mechanism, so as to provide new ideas for the treatment of sepsis. MethodThe previous literatures and latest research results about mitochondrial metabolism during sepsis were reviewed. ResultsAt present, the researchers were not only concerned about the inflammatory response of sepsis, but also concerned about the systemic metabolic disorder caused by sepsis. It was believed that the damage of mitochondria caused by sepsis was one of the main reasons for the disorder of cell metabolism. During the sepsis, the patient’s metabolism had changed, for example, enhancement of aerobic glycolysis, lactic acid accumulation, elevated levels of fatty acids and triglycerides in blood, and so on. ConclusionMetabolic change during sepsis is related to mitochondria, which can provide some new methods for treatment of sepsis.
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.
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.
Optic atrophy,hereditary／diagnosis; Polymerase chain reaction; DNA,mitochondrial; Point mutation; Sequence analysis
Objective To investigate the role of mitochondrial autophagy mediated by PINK1 (homologous phosphatase tensin induced kinase 1) /Parkin (Parkinson’s protein) signaling pathway in severe pneumonia of rats. Methods Twenty rats were randomly divided into control group and model group (severe pneumonia model), with 10 rats in each group, to explore the effects of severe pneumonia on lung function and pathology in rats. Then, 30 rats were randomly divided into control group, model group and mdivi-1 (mitochondrial autophagy inhibitor) group, with 10 rats in each group, to further explore the effects of severe pneumonia on mitochondrial autophagy indicators of rats. ResultsCompared with the control group, the resting ventilation volume [(3.44±0.22) vs. (1.58±0.18) mL/min] and airway resistance ratio (77.48±3.84 vs. 47.76±5.54) in the model group were decreased (P<0.05). In the model group, the lung tissue was injured and a large number of inflammatory cells were infiltrated. The protein and mRNA expression levels of Parkin, PINK1 and microtubule-associated protein1 light chain 3 in lung tissues of model group were increased (P<0.05). Compared with model group, the ratio of resting ventilator-to-airway resistance in mdivi-1 group increased (P<0.05). The injury and inflammatory infiltration of lung tissue were improved in mdivi-1 group. The expression levels of Parkin, PINK1 and microtubule-associated protein1 light chain 3 protein and mRNA in lung tissues of mdivi-1 group were decreased (P<0.05). Conclusion Mdivi-1 can improve the abnormal lung function structure in rats with severe pneumonia, and the mechanism may be related to mitochondrial autophagy mediated by PINK1/Parkin signaling pathway.
Leber’s hereditary optic neuropathy (LHON) is a paradigm maternal hereditary eye disease, mainly involving the retinal and macular fibers of the optic disc in the anterior ethmoid plate of the sclera. LHON has the characteristics of sex bias among males and incomplete penetrance. Primary mitochondrial DNA mutations m.11778G>A, m. 14484T>C, m.3460G>A are the molecular basis of LHON. However, other risk factors, such as secondary mitochondrial DNA mutations, mitochondrial haplotypes, nuclear modification genes, estrogen, vitamin B12 and environmental factors, work together to affect its phenotypic expression. The clinical diagnosis of LHON mainly limited to the detection of the primary mutation site of mitochondrial DNA. Therefore, comprehensive analysis of multiple risk factors of LHON will facilitate to construct multi-dimensional model of prevention, diagnosis and treatment system, which provide accurate and individualized medical services for patients. These may alleviate the incidence in LHON families. It also provides new ideas and different angles for the in-depth study of the pathogenesis of LHON.
Mitochondrial DNA (mtDNA) is the circulating genome in mitochondria, and it is easy to accumulate oxidative damage, causing mitochondrial dysfunction, and then cell dysfunction, and even tissue and body pathological changes, leading to diseases. As a pro-inflammatory, inflammatory, and even predictive factor, mtDNA is directly involved in the inflammatory response and the pathogenesis of many diseases. This article aims to review the current pathogenesis of mtDNA damage and its pathogenic role in various human diseases.
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)
ObjectiveTo investigate the expression of circular RNA mitochondrial fusin 2 (circ-MFN2) in pancreatic cancer and analyze its correlation with clinicopathological features and prognosis.MethodsThe expressions of circ-MFN2 miRNA in 55 cases of pancreatic cancer tissues and serum were detected by qRT-PCR, and analyzed the correlation between circ-MFN2 and clinicopathological factors of pancreatic cancer and prognosis. The sensitivity, specificity and accuracy of expression of circ-MFN2 miRNA in the diagnosis of pancreatic cancer were statistically analyzed. ROC curve was used to analyze its efficacy as a biomarker for early diagnosis of pancreatic cancer.ResultsCompared with paracancerous tissues of pancreatic cancer and serum of healthy control group, circ-MFN2 miRNA was highly expressed in pancreatic cancer tissues and serum, and the difference were all statistically significant (all P<0.05). Chi square test showed that the expression of circ-MFN2 miRNA in pancreatic cancer tissues was not related to age, gender, tumor size, pathological type, and tumor site (P>0.05), but was significantly related to CA19-9 level, TNM stage, tumor differentiation and lymph node metastasis (P<0.05). The sensitivity, specificity and accuracy of expression of circ-MFN2 miRNA for pancreatic cancer were 72.7%, 70.9% and 83.6% respectively, which were all higher than that of CA19-9 (54.5%, 50.9% and 52.7%, P<0.05). Kaplan-Meier analysis showed that the median survival time of pancreatic cancer patients with high expression of circ-MFN2 miRNA was significantly shorter than that of patients with low expression (9.1 months vs 22.3 months, P<0.05). The area under ROC curve of circ-MFN2 miRNA as a serum biomarker for the diagnosis of pancreatic cancer was 0.861 [95%CI (0.775, 1.157), P=0.000]. Cox multivariate analysis showed that the expression of cirC-MFN2 miRNA and lymph node metastasis were independent risk factors for the prognosis of pancreatic cancer patients.ConclusionsCirc-MFN2 miRNA is highly expressed in pancreatic cancer tissues, and it is related to the clinical characteristics and prognosis of patients. It is expected to be a new molecular marker to predict the prognosis of pancreatic cancer.
Objective To summarize the role of chondrocytes mitochondrial biogenesis in the pathogenesis of osteoarthritis (OA), and analyze the applications in the treatment of OA. Methods A review of recent literature was conducted to summarize the changes in mitochondrial biogenesis in the course of OA, the role of major signaling molecules in OA chondrocytes, and the prospects for OA therapeutic applications. Results Recent studies reveales that mitochondria are significant energy metabolic centers in chondrocytes and its dysfunction has been considered as an essential mechanism in the pathogenesis of OA. Mitochondrial biogenesis is one of the key processes maintaining the normal quantity and function of mitochondria, and peroxisome proliferator-activated receptor-gamma coactivator 1 alpha (PGC-1α) is the central regulator of this process. A regulatory network of mitochondrial biogenesis with PGC-1α as the center, adenosine monophosphate-activated protein kinase, sirtuin1/3, and cyclic adenosine monophosphate response element-binding protein as the main upstream regulatory molecules, and nuclear respiratory factor 1, estrogen-related receptor α, and nuclear respiratory factor 2 as the main downstream regulatory molecules has been reported. However, the role of mitochondrial biogenesis in OA chondrocytes still needs further validation and in-depth exploration. It has been demonstrated that substances such as puerarin and omentin-1 can retard the development of OA by activating the damaged mitochondrial biogenesis in OA chondrocytes, which proves the potential to be used in the treatment OA. ConclusionMitochondrial biogenesis in chondrocytes plays an important role in the pathogenesis of OA, and further exploring the related mechanisms is of great clinical significance.