1.Porphyromonas gingivalis infection promotes mitochondrial dysfunction through Drp1-dependent mitochondrial fission in endothelial cells.
Tong XU ; Qin DONG ; Yuxiao LUO ; Yanqing LIU ; Liang GAO ; Yaping PAN ; Dongmei ZHANG
International Journal of Oral Science 2021;13(1):28-28
Porphyromonas gingivalis (P. gingivalis), a key pathogen in periodontitis, has been shown to accelerate the progression of atherosclerosis (AS). However, the definite mechanisms remain elusive. Emerging evidence supports an association between mitochondrial dysfunction and AS. In our study, the impact of P. gingivalis on mitochondrial dysfunction and the potential mechanism were investigated. The mitochondrial morphology of EA.hy926 cells infected with P. gingivalis was assessed by transmission electron microscopy, mitochondrial staining, and quantitative analysis of the mitochondrial network. Fluorescence staining and flow cytometry analysis were performed to determine mitochondrial reactive oxygen species (mtROS) and mitochondrial membrane potential (MMP) levels. Cellular ATP production was examined by a luminescence assay kit. The expression of key fusion and fission proteins was evaluated by western blot and immunofluorescence. Mdivi-1, a specific Drp1 inhibitor, was used to elucidate the role of Drp1 in mitochondrial dysfunction. Our findings showed that P. gingivalis infection induced mitochondrial fragmentation, increased the mtROS levels, and decreased the MMP and ATP concentration in vascular endothelial cells. We observed upregulation of Drp1 (Ser616) phosphorylation and translocation of Drp1 to mitochondria. Mdivi-1 blocked the mitochondrial fragmentation and dysfunction induced by P. gingivalis. Collectively, these results revealed that P. gingivalis infection promoted mitochondrial fragmentation and dysfunction, which was dependent on Drp1. Mitochondrial dysfunction may represent the mechanism by which P. gingivalis exacerbates atherosclerotic lesions.
Endothelial Cells
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Mitochondria
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Mitochondrial Dynamics
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Porphyromonas gingivalis
2.Progress in regulation of mitochondrial dynamics and mitochondrial autophagy.
Jing CHENG ; Lin WEI ; Miao LI
Acta Physiologica Sinica 2020;72(4):475-487
The abnormality of mitochondrial morphology and function is closely related to the pathogenesis of many diseases. Mitochondrial fusion-fission dynamics are critical to maintain normal morphology, distribution and quantity of mitochondria, and ensure the normal activity of cells. In addition, mitochondrial autophagy (mitophagy) plays an important role in maintaining mitochondrial quality by degrading aging or damaged mitochondria. Many previous studies showed that mitochondrial dynamics and mitophagy can regulate each other to sustain mitochondrial network homeostasis. Clarifying regulatory mechanisms of mitochondrial dynamics and mitophagy is of great significance for revealing the molecular mechanism of various diseases and for the development of new drugs targeting mitochondrial dynamics proteins or mitophagy regulatory proteins. This review focuses on the role of mitochondrial dynamics and mitophagy in mitochondrial quality control, regulatory mechanism, the interplay between those two processes, and their roles in human-related diseases.
Autophagy
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Humans
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Mitochondria
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Mitochondrial Dynamics
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Mitochondrial Proteins
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Mitophagy
3.Physiological and Pathological Significance of Dynamin-Related Protein 1 (Drp1)-Dependent Mitochondrial Fission in the Nervous System.
Bongki CHO ; So Yoen CHOI ; Hyo Min CHO ; Hyun Jung KIM ; Woong SUN
Experimental Neurobiology 2013;22(3):149-157
Mitochondria are essential for proper neuronal morphogenesis and functions, as they are the major source of energy for neural development. The dynamic morphology of mitochondria determines the key functions of mitochondria. Several regulatory proteins such as dynamin-related protein 1 (Drp1) are required to maintain mitochondrial morphology via a balance between continuous fusion and fission. Activity of Drp1, a key regulator in mitochondrial fission, is modulated by multiple post-translation modifications and receptor interactions. In addition, numerous researches have revealed that the regulation of Drp1 activity and mitochondrial dynamics is closely associated with several neurodegenerative diseases such as Alzheimer's and Parkinson's diseases. In this article, we concisely review the recent findings about the biological importance of Drp1-mediated mitochondrial fission in neurons under physiological and pathological conditions.
Mitochondria
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Mitochondrial Dynamics
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Morphogenesis
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Nervous System
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Neurodegenerative Diseases
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Neurons
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Proteins
4.Research progress of optic atrophy 1-mediated mitochondrial dynamics in skeletal system diseases.
Kaibo SUN ; Yuangang WU ; Yi ZENG ; Mingyang LI ; Limin WU ; Bin SHEN
Chinese Journal of Reparative and Reconstructive Surgery 2023;37(6):758-763
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
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GTP Phosphohydrolases/genetics*
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Mitochondrial Dynamics
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Osteoarthritis
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Osteoporosis
5.Research advances in relationship between mitochondrial dynamics and cellular energy metabolism and exercise intervention.
Acta Physiologica Sinica 2019;71(4):625-636
Mitochondrial dynamics, involving mitochondrial fusion, fission and autophagy, plays an important role in maintaining cellular physiological function and homeostasis. Mitochondria are the "energy plant" of human body, so the changes of mitochondrial fusion, division and autophagy are important for cell respiration and energy production. On the other hand, energy metabolism influences mitochondrial dynamics in turn. This paper reviewed the recent advances in studies on the relationship between energy metabolism and the proteins regulating mitochondrial fusion, fission and autophagy. The association of mitochondrial dynamics with electron chain complex expression, oxidative phosphorylation and ATP synthesis upon exercise intervention will provide theoretical references for the further studies in sports training and disease intervention.
Adenosine Triphosphate
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biosynthesis
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Autophagy
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Energy Metabolism
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Exercise
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Humans
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Mitochondria
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physiology
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Mitochondrial Dynamics
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Mitochondrial Proteins
;
metabolism
6.Gene knockout technology and its application in the study of the relationship between mitochondrial dynamics and insulin resistance.
Jia XU ; Yueqi GUAN ; Zhiyi YU ; Chengshuai ZHANG ; Fengying GUAN ; Fen LIU
Chinese Journal of Biotechnology 2019;35(8):1382-1390
Mitochondrial dynamics, the processes of mitochondrial fusion and fission maintain homeostasis, are precisely regulated by fusion/fission-related proteins, and play an important physiological role in mitochondrial metabolism, quality and function. The aberrant changes of these proteins can trigger mitochondrial dynamics imbalance, which cause mitochondrial dysfunctions and result various disease states. This article focuses on gene knockout technology, and reviews the role and application progress of genes encoding for fusion and fission knockout mice in insulin resistance researches, in order to lay a foundation for future studies on signal transduction mechanism of mitochondrial dynamics imbalance in insulin resistance.
Animals
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Gene Knockout Techniques
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Insulin Resistance
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Mice
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Mitochondria
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Mitochondrial Dynamics
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Mitochondrial Proteins
7.Effects of vibration on the expression of mitochondrial fusion and fission genes and ultrastructure of skeletal muscle in rabbits.
Jia Xuan LI ; Shuang Yan XIE ; Zhao Qiang ZHANG ; Chun Zhi ZHANG ; Li LIN
Chinese Journal of Industrial Hygiene and Occupational Diseases 2022;40(1):18-23
Objective: To study the effects of vibration on the expression of mitochondrial fusion and fission genes and ultrastructure of skeletal muscle in rabbits. Methods: Thirty-two 3.5-month-old New Zealand rabbits were randomly divided into low-intensity group, medium-intensity group, high-intensity group and control group, with 8 rabbits in each group. The rabbits in the experimental group were subjected to hind limb vibration load test for 45 days. The vibration intensity of the high intensity group was 12.26 m/s(2), the medium intensity group was 6.13 m/s(2), and the low intensity group was 3.02 m/s(2) according to the effective value of weighted acceleration[a(hw (4))] for 4 hours of equal energy frequency. The control group was exposed to noise only in the same experimental environment as the medium-intensity group. The noise levels of each group were measured during the vibration load experiment. After the test, the mRNA expression of mitochondrial fusion gene (Mfn1/Mfn2) and fission gene (Fis1, Drp1) by RT-PCR in the skeletal muscles were measured and the ultrastructure of the skeletal muscles were observed in high intensity group. Results: The mRNA expression of mitochondrial in the skeletal muscle tissues of control group, low intensity group, medium intensity group and high intensity group were Mfn1: 3.25±1.36, 3.85±1.90, 4.53±2.31 and 11.63±7.68; Mfn2: 0.68±0.25, 1.02±0.40, 0.94±0.33 and 1.40±0.45; Fis1: 1.05±0.62, 1.15±0.59, 1.53±1.06 and 2.46±1.51 and Drp1: 3.72±1.76, 2.91±1.63, 3.27±2.01 and 4.21±2.46, respectively. Compared with the control group, the expressions of Mfn1 mRNA, Mfn2 mRNA and Fis1 mRNA in the high-intensity group increased significantly (P<0.05) , and the expressions of Mfn2 mRNA in the medium-intensity group and the low-intensity group increased significantly (P<0.05) . Compared with the control group, the ultrastructure of skeletal muscle of high intensity group showed mitochondrial focal accumulation, cristae membrane damage, vacuole-like changes; Z-line irregularity of muscle fibers, and deficiency of sarcomere. Conclusion: Vibration must be lead to the abnormal mitochondrial morphology and structure and the disorder of energy metabolism due to the expression imbalance of mitochondrial fusion and fission genes in skeletal muscles of rabbits, which may be an important target of vibration-induced skeletal muscle injury.
Animals
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Hindlimb/metabolism*
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Mitochondria/metabolism*
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Mitochondrial Dynamics
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Mitochondrial Proteins/pharmacology*
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Muscle, Skeletal
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Rabbits
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Vibration/adverse effects*
8.Clinical and Genetic Characteristics in Patients of Charcot-Marie-Tooth type 2A with Mitofusin 2 (MFN2) Mutations.
Byung Ok CHOI ; Sang Beom KIM ; Kee Duk PARK ; Kyoung Gyu CHOI ; Jeeyoung OH ; Bum Chun SUH ; Se Hoon KIM ; Dae Seong KIM ; Jeong Geun LIM ; In Soo JOO ; Seung Min KIM ; Il Nam SUNWOO ; Eun Kyoung YUN ; Chan Goo CHUNG ; Chung Choo LEE ; Yongseong KIM ; Min Chul LEE ; Ki Wha CHUNG
Journal of the Korean Neurological Association 2006;24(2):131-140
BACKGROUND: Mitofusin 2 (MFN2) is a membrane protein and is an essential component of mitochondrial fusion machinery. Mitochondrial fusion is essential for various biological functions in mammalian cells. Thus mutations in MFN2 are the underlying cause of Charcot-Marie-Tooth neuropathy type 2A (CMT2A). However, there has been no reports investigating the MFN2 genes in Korean CMT patients. Therefore, we investigated to find the clinical and genetic characteristics in Korean patients with the MFN2 gene mutation. METHODS: We examined the mutations of the MFN2 gene in 137 Korean CMT families. According to criteria from the European CMT consortium, CMT2 was 45 families. Mutations were confirmed by both strands sequencing. Nerve conduction studies were carried out in CMT patients having each mutation. RESULTS: Eight pathogenic mutations were found in 10 families. Six mutations (Leu92Pro, Gly127Asp, His165Arg, Ser263Pro, Arg364Trp, Met376Thr) were determined to be novel, and those were not detected in the 100 healthy controls. A de novo missense mutation was found in three CMT families (30%). The frequency of the MFN2 mutation was 22.2%, which was higher than those found in the Cx32 mutation. In CMT2A, the frequencies with early age at onset (<10 years) and flat feet were 46.2%. CONCLUSIONS: We found MFN2 mutations in patients with sporadic or dominantly inherited CMT. In the majority of cases with CMT type 2, the axonal neuropathy, may be due to MFN2 mutations.
Axons
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Charcot-Marie-Tooth Disease
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Flatfoot
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Humans
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Membrane Proteins
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Mitochondrial Dynamics
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Mutation, Missense
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Neural Conduction
9.Control of Mitochondrial Dynamics by Fas-induced Caspase-8 Activation in Hippocampal Neurons.
Experimental Neurobiology 2015;24(3):219-225
Cells undergo apoptosis mainly via two pathways-the mitochondrial pathway and the cytosolic pathway. It has been well documented that activation of the mitochondrial pathway promotes mitochondrial fragmentation and inhibition of mitochondrial fragmentation partly represses cell death. However, the mitochondrial events following activation of the cytosolic pathway are less understood. In this study, we treated Fas-activating antibody and found mitochondrial fragmentation without cell death in hippocampal primary neurons and HT-22 cell lines. Fas antibody treatment, in fact, promoted rapid activation of caspase-8, while executioner caspase-3 activation was not observed. Furthermore, blockage of caspase-8 efficiently prevented Fas antibody-induced mitochondrial fragmentation. These results suggest that the cytosolic pathway induced by death receptor activation promotes caspase-8-dependent mitochondrial fission.
Apoptosis
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Caspase 3
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Caspase 8*
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Cell Death
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Cell Line
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Cytosol
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Mitochondrial Dynamics*
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Neurons*
10.Mitochondrial Dynamics in the Heart as a Novel Therapeutic Target for Cardioprotection
Chonnam Medical Journal 2013;49(3):101-107
Traditionally, mitochondria have been regarded solely as energy generators for cells; however, accumulating data have demonstrated that these complex organelles play a variety of roles within the cardiomyocyte that extend beyond this classic function. Mitochondrial dynamics involves mitochondrial movements and morphologic alterations by tethering, fusion, and fission, which depend on cellular energy requirements and metabolic status. Many studies have indicated that mitochondrial dynamics may be a fundamental component of the maintenance of normal cellular homeostasis and cardiac function. Mitochondrial dynamics is controlled by the protein machinery responsible for mitochondrial fusion and fission, but cardiomyocytes are densely packed as part of an intricate cytoarchitecture for efficient and imbalanced contraction; thus, mitochondrial dynamics in the adult heart are restricted and occur more slowly than in other organs. Cardiac mitochondrial dynamics is important for cardiac physiology in diseased conditions such as ischemia-reperfusion (IR) injury. Changes in mitochondrial morphology through modulation of the expression of proteins regulating mitochondrial dynamics demonstrates the beneficial effects on cardiac performance after IR injury. Thus, accurately defining the roles of mitochondrial dynamics in the adult heart can guide the identification and development of novel therapeutic targets for cardioprotection. Further studies should be performed to establish the exact mechanisms of mitochondrial dynamics.
Adult
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Heart
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Homeostasis
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Humans
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Mitochondria
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Mitochondrial Dynamics
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Myocardial Reperfusion Injury
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Myocytes, Cardiac
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Organelles
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Physiology