Objective To explore the feasibility of identifying clonal origin of hepatocellular carcinoma (HCC) by analyzing the mitochondrial DNA D-Loop region variations. Methods Forty-two patients with a total of 112 HCC nodules consequentially hospitalized for radical resection of HCC in the department of hepatobiliary surgery of the First Affiliated Hospital of Guangxi Medical University from April 2004 to August 2007 were included for study group (multinodular HCCs). Control group included 20 cases of HCC (40 samples) hospitalized in the same period that consisted of two sub-groups: control groupⅠconsisted of 16 cases of single nodular HCC that each had two pieces of inconsecutive tumor tissues and control groupⅡconsisted of 4 cases of HCC with portal vein tumor embolus whose tumor tissues and portal vein tumor embolus were collected simultaneously. Normal control included 5 patients who were donors for liver transplantation or underwent liver trauma without any liver disease. Polymerase chain reaction (PCR) and direct sequencing were applied to study the mtDNA D-Loop region. The sequences of multinodular lesions were compared among different groups. Results For all the 42 cases of the study group, basic group variations appeared in 131 sites (131/1 122, 11.7%, the number 1 122 was the length of mtDNA D-Loop) with point mutation in 15 sites, insert in 9 sites, and deletion in 16 sites. And of all the variations in the study group, 98 were polymorphism. In study group, 20 cases were categorized as multicentric occurrence (MO) based on their variant mtDNA D-Loop sequences in each nodule from the same patient. And 22 cases were characterized as intrahepatic metastasis (IM) based on the identical mtDNA D-Loop sequences found in each nodule from the same patient. In all 20 cases in the control group, the inconsecutive tumor tissues or the portal vein tumor embolus and original tumors shared identical mtDNA D-Loop sequences. For the normal control group, basic group variations appeared in 14 sites, and they were all polymorphism including a new polymorphism (NT 479 Agt;G). Conclusions There is a high rate of changes in mtDNA D-Loop region. And our study speculates a novel discrimination of MO and IM origins among multinodular HCCs using PCR and direct sequencing of the mtDNA D-Loop sequences.
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.
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.
Leber hereditary optic neuropathy (LHON) is a blinding disease caused by mutations in mitochondrial DNA. It is a classic disease model for studying mitochondrial abnormalities. Its main mutation sites are m11778G.A, m.3460G.A and m.14484T.C. LHON cell models are mainly produced by lymphoblasts, fibroblasts, cell hybrids and induced pluripotent stem cells, while LHON animal models are mainly mice, which are produced by rotenone and ND4 mutants. Although the research on the LHON model has achieved good results, there are still many difficulties in constructing an ideal experimental model, which severely limit the exploring to the pathogenesis and therapeutic drugs of LHON. A detailed understanding of the application and characteristics of existing models in LHON will help improve experimental design and construct new models.
Diabetic retinopathy (DR) is one of the most common microvascular complications of diabetes, characterized by high blindness rates and a severe impact on patients' quality of life. Despite adequate glycemic control, some patients exhibit persistent progression of retinal microvascular damage, known as the "metabolic memory" phenomenon. Studies have revealed that the essence of this phenomenon is the sustained expression of epigenetic reprogramming induced by metabolic stress, in which abnormal mitochondrial DNA (mtDNA) methylation plays a pivotal role. Metabolic abnormalities such as hyperglycemia, hyperhomocysteinemia, and hyperlipidemia can alter mtDNA methylation patterns, triggering cascading pathological processes including oxidative stress, chronic inflammation, and neurovascular network disorders, remodeling mitochondrial energy metabolism, and promoting the evolution of DR from subclinical compensatory stage to irreversible structural damage. Abnormal mtDNA methylation serves as a hallmark of metabolic memory and a core driver of microvascular lesions, providing an important theoretical basis for in-depth analysis of metabolic memory mechanisms and exploration of DR intervention strategies. Current research needs to further elucidate its role in DR. Future efforts require integration of multi-dimensional epigenetic biomarkers, precise intervention approaches, and clinical translational research to advance the early diagnosis and individualized treatment of DR.
Mitochondrial quality control includes mechanisms such as mitochondria-derived vesicles, fusion / fission and autophagy. These processes rely on the collaboration of a variety of key proteins in the inner and outer membranes of mitochondria to jointly regulate the morphological structure and functional integrity of mitochondria, repair mitochondrial damage, and maintain the homeostasis of their internal environment. The imbalance of mitochondrial quality control is associated with leukemia. Therefore, by exploring the mechanisms related to mitochondrial quality control of various leukemia cells and their interactions with immune cells and immune microenvironment, this article sought possible targets in the treatment of leukemia, providing new ideas for the immunotherapy of leukemia.
Nuclear factor-erythroid 2-related factor 2 (Nrf2) is an important factor for cells to resist oxidative stress and electrophilic attack. It is involved in the formation and control of oxidative stress defense pathways. It is associated with oxidative stress-related diseases, including cancer, neurodegenerative diseases, cardiovascular diseases and aging, and is a potential pharmacological target for the treatment of chronic diseases. This article will review the important role of Nrf2 in the regulation of cell proliferation, including direct regulation of cell proliferation, regulation of reactive oxygen species, intracellular metabolism, regulation of mitochondrial function, cell lifespan and inflammatory response. The aim is to provide a theoretical basis for further research on how to use Nrf2 to regulate cell proliferation.
【Abstract】 Objective To analyze the correlations between the mt5351G and mt6680C genotypes in mitochondrial DNA ( mtDNA) haplogroup M and susceptibility to high altitude pulmonary edema ( HAPE)among the Hans. Methods Specimens from206 Hans cases of HAPE and 144 matched Hans controls were collected. Then PCR-RFLP method was used to determine haplogroup M and N of mtDNA, and PCR-LDR was used to genotype mt5351G and mt6680C in the haplogroup M in these samples. Results The frequencies of haplogroup Mand N were 49. 0% and 51.0% in the HAPE patients, and 47. 2% and 52. 8% in the controls, respectively, with no significant difference between the HAPE patients and the controls. In the haplogroup M, the genotype of mt6680C and mt5351G frequencies in the HAPE patients were both significantly higher than the controls ( both 12. 0% vs. 1. 5% , P = 0. 016) . Conclusion The existence of mt5351G and mt6680C genotypes in the haplogroup Mis a risk factor for HAPE among the Hans.
Objective To investigate the preventive and therapeutic effects and the mechanisms of pyrrol idine dithiocarbamate (PDTC) on the atrophy of denervated skeletal muscle. Methods Thirty adult Wistar rats of either gender, weighing (200 ± 10) g were randomly divided into 3 groups: group A (n=6, control group), group B (n=12, denervation group), and group C (n=12, PDTC treatment group). The sciatic nerves of the rats were only exposed without cutting off in group A, and the rats were made denervated gastrocnemius models in groups B and C. PDTC of 100 mg/(kg?d) was injected peritoneally in group C and an intraperitoneal injection of the same amount normal sal ine was given in group B. After 14 and 28 days, the gastrocnemius was harvested to measure the ratio of muscle wet weight; the levels of nuclear factor of κB (NF-κB)p65 protein and the opening of the mitochondrial permeabil ity transition pore (MPTP) in the gastrocnemius were detectedrespectively by Western blot and laser confocal scanning microscope; and the apoptotic cells in atrophic muscle were measured with TUNEL. Results The ratio of muscle wet weight in group A was 1.039 ± 0.115, and it significantly decreased in groups B and C (P lt; 0.05); after 14 and 28 days of operation, the ratio of muscle wet weight in group C significantly increased when compared with those in group B (P lt; 0.05). The expression of NF-κB p65 protein in group A was 0.224 ± 0.041; the expressions of NF-κB p65 in groups B and C significantly increased when compared with that in group A (P lt; 0.05); however, the expression of NF-κB p65 in group C was significantly lower than that in group B (P lt; 0.05). The MPTP fluorescence intensity in group A was 31.582 ± 1.754; the MPTP fluorescence intensity was significantly lower in groups B and C than in group A (P lt; 0.05), and the MPTP fluorescence intensity in group C was significantly higher than that in group B (P lt; 0.05). The rate of apoptosis in group A was 4.542% ± 0.722%; after 14 and 28 days of operation, the rates of apoptosis significantly increased when compared groups B and C with group A, and signiticantly decreased when compared group C with group B (P lt; 0.05). Conclusion PDTC can retard denervated skeletal muscle atrophy, and the effect may have a relationship with its inhibition on NF-κB, the opening of the MPTP, and the ratio of apoptosis.
ObjectiveTo observe the effects of p21 activated kinase 4 (PAK4) on the mitochondrial function and biological behavior in retinal vascular endothelial cells. MethodsThe experimental study was divided into two parts: in vivo animal experiment and in vitro cell experiment. In vivo animal experiments: 12 healthy C57BL/6J male mice were randomly divided into normal control group and diabetes group, with 6 mice in each group. Diabetes mice were induced by streptozotocin to establish diabetes model. Eight weeks after modeling, quantitative real-time polymerase chain reaction and Western blots were performed to detect the expression of PAK4 in diabetic retinas. In vitro cell experiments: the human retinal microvascular endothelial cells (hRMEC) were divided into three groups: conventional cultured cells group (N group), empty vector transfected (Vector group); pcDNA-PAK4 eukaryotic expression plasmid transfected group (PAK4 group). WB and qPCR were used to detect transfection efficiency, while scratching assay, cell scratch test was used to detect cell migration in hRMEC of each group. In vitro white blood cell adhesion experiment combined with 4 ', 6-diamino-2-phenylindole staining was used to detect the number of white blood cells adhering to hRMEC in each group. The Seahorse XFe96 cell energy metabolism analyzer measures intracellular mitochondrial basal respiration, adenosine triphosphate (ATP) production, maximum respiration, and reserve respiration capacity. The t-test was used for comparison between the two groups. Single factor analysis of variance was used for comparison among the three groups. ResultsIn vivo animal experiments: compared with normal control group, the relative expression levels of PAK4 mRNA and protein in retina of diabetic mice were significantly increased, with statistical significance (t=25.372, 22.419, 25.372; P＜0.05). In vitro cell experiment: compared with the N group and Vector group, the PAK4 protein, mRNA relative expression and cell mobility in the hRMEC of PAK4 group were significantly increased, with statistical significance (F=36.821, 38.692, 29.421; P＜0.05). Flow cytometry showed that the adhesion number of leukocytes on hRMEC in PAK4 group was significantly increased, and the difference was statistically significant (F=39.649, P＜0.01). Mitochondrial pressure measurement results showed that the capacity of mitochondrial basic respiration, ATP production, maximum respiration and reserve respiration in hRMEC in PAK4 group was significantly decreased, with statistical significance (F=27.472, 22.315, 31.147, 27.472; P＜0.05). ConclusionOver-expression of PAK4 impairs mitochondrial function and significantly promotes leukocyte adhesion and migration in retinal vascular endothelial cells.
