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This study aims to investigate the effect of salvianolic acid B (Sal B), the active ingredient of Salvia miltiorrhiza, on H9C2 cardiomyocytes injured by oxygen and glucose deprivation/reperfusion (OGD/R) through regulating mitochondrial fission and fusion. The process of myocardial ischemia-reperfusion injury was simulated by establishing OGD/R model. The cell proliferation and cytotoxicity detection kit (cell counting kit-8, CCK-8) was used to detect cell viability; the kit method was used to detect intracellular reactive oxygen species (ROS), total glutathione (t-GSH), nitric oxide (NO) content, protein expression levels of mitochondrial fission and fusion, apoptosis-related detection by Western blot. Mitochondrial permeability transition pore (MPTP) detection kit and Hoechst 33342 fluorescence was used to observe the opening level of MPTP, and molecular docking technology was used to determine the molecular target of Sal B. The results showed that relative to control group, OGD/R injury reduced cell viability, increased the content of ROS, decreased the content of t-GSH and NO. Furthermore, OGD/R injury increased the protein expression levels of dynamin-related protein 1 (Drp1), mitofusions 2 (Mfn2), Bcl-2 associated X protein (Bax) and cysteinyl aspartate specific proteinase 3 (caspase 3), and decreased the protein expression levels of Mfn1, increased MPTP opening level. Compared with the OGD/R group, it was observed that Sal B had a protective effect at concentrations ranging from 6.25 to 100 μmol·L-1. Sal B decreased the content of ROS, increased the content of t-GSH and NO, and Western blot showed that Sal B decreased the protein expression levels of Drp1, Mfn2, Bax and caspase 3, increased the protein expression level of Mfn1, and decreased the opening level of MPTP. In summary, Sal B may inhibit the opening of MPTP, reduce cell apoptosis and reduce OGD/R damage in H9C2 cells by regulating the balance of oxidation and anti-oxidation, mitochondrial fission and fusion, thereby providing a scientific basis for the use of Sal B in the treatment of myocardial ischemia reperfusion injury.
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ObjectiveTo explore whether the mechanism of Shuangshen Ningxin capsules （SSNX） in alleviating myocardial ischemia-reperfusion injury （MIRI） in rats is related to the regulation of mitochondrial fission and fusion. MethodThis study focused on Sprague Dawley （SD） rats and ligated the left anterior descending branch of the coronary artery to construct a rat model of MIRI. The rats were divided into the sham operation group， model group， SSNX group （90 mg·kg-1） and trimetazidine group （5.4 mg·kg-1）. The activity of superoxide dismutase （SOD） and the content of malondialdehyde （MDA） were detected by micro method. Changes in mitochondrial membrane potential （△Ψm） and the degree of mitochondrial permeability transition pore （mPTP） opening were detected by the chemical fluorescence method. The intracellular adenosine triphosphate （ATP） level was detected by the luciferase assay. The messenger ribonucleic acid （mRNA） and protein expression levels of mitochondrial fission and fusion related factors dynamin-related protein 1 （DRP1）， mitochondrial fission 1 protein （FIS1）， optic atrophy protein 1 （OPA1）， mitochondrial outer membrane fusion protein 1 （MFN1）， and MFN2 were detected by real-time polymerase chain reaction （real-time PCR） and Western blot. ResultCompared with the sham operation group， the model group showed a decrease in serum SOD activity and an increase in MDA content. The opening level of mPTP， the level of △Ψm and ATP content decreased， the protein expressions of mitochondrial fission factors DRP1 and FIS1 increased， and the protein expressions and mRNA transcription levels of fusion related factors OPA1 and MFN1 decreased. Compared with the model group，SSNX significantly increased serum SOD activity， reduced MDA content， increased intracellular ATP level and △Ψm， reduced the opening level of mPTP， downregulated the protein expressions of mitochondrial fission factors DRP1 and FIS1， and increased the mRNA transcription levels and protein expressions of fusion related factors OPA1 and MFN1. ConclusionSSNX inhibits the expressions of mitochondrial fission factors DRP1 and FIS1， and increases the expressions of fusion related factors OPA1 and MFN1， inhibiting mitochondrial fission and increasing mitochondrial fusion， thereby alleviating MIRI.
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Mitochondrial dynamics are a contraversal issue in hepatocellular carcinoma. The present study tries to illustrate the role of mitochondrial dynamics proteins (mitofusin-2 (Mfn2) and YME1L) in hepatocarcinogenesis. Five groups were used: the control group and three HCC groups (after 8, 16, and 24 weeks from DENA induction). The last group was treated with Sorafenib (SP) (10 mg/kg), via oral gavage for 4 weeks after cancer induction. This study revealed that Mfn-2 was downregulated and YME1l was overexpressed in different HCC groups. This dysregulation of mitochondrial dynamics proteins was associated with high hepatic levels of cyclin D1, MMP-9, and MDA and overexpression of ki67 as well as decreasing the hepatic expression of tissue inhibitor of matrix metalloproteinase-3 (Timp-3) and Bax. To confirm the possible role of Mfn2 and YME1L in HCC, we assessed the effect of sorafenib on these parameters and its related HCC characteristics. Sorafenib corrected the level of Mfn2 and YME1L and decreased tumor cell proliferation as well. We also elucidated that mitochondrial dynamics proteins (Mfn2 and YME1L) could be a good therapeutic target for HCC.
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Epidemiological and animal studies indicate that pre-existing diabetes increases the risk of Parkinson's disease(PD).However,the mechanisms underlying this association remain unclear.In the present study,we found that high glucose(HG)levels in the cerebrospinal fluid(CSF)of diabetic rats might enhance the effect of a subthreshold dose of the neurotoxin 6-hydroxydopamine(6-OHDA)on the development of motor disorders,and the damage to the nigrostriatal dopaminergic neuronal pathway.In vitro,HG promoted the 6-OHDA-induced apoptosis in PC12 cells differentiated to neurons with nerve growth factor(NGF)(NGF-PC12).Metabolomics showed that HG promoted hyperglycolysis in neurons and impaired tricarboxylic acid cycle(TCA cycle)activity,which was closely related to abnormal mito-chondrial fusion,thus resulting in mitochondrial loss.Interestingly,HG-induced upregulation of pyruvate kinase M2(PKM2)combined with 6-OHDA exposure not only mediated glycolysis but also promoted abnormal mitochondrial fusion by upregulating the expression of MFN2 in NGF-PC12 cells.In addition,we found that PKM2 knockdown rescued the abnormal mitochondrial fusion and cell apoptosis induced by HG+6-OHDA.Furthermore,we found that shikonin(SK),an inhibitor of PKM2,restored the mito-chondrial number,promoted TCA cycle activity,reversed hyperglycolysis,enhanced the tolerance of cultured neurons to 6-OHDA,and reduced the risk of PD in diabetic rats.Overall,our results indicate that diabetes promotes hyperglycolysis and abnormal mitochondrial fusion in neurons through the upre-gulation of PKM2,leading to an increase in the vulnerability of dopaminergic neurons to 6-OHDA.Thus,the inhibition of PKM2 and restoration of mitochondrial metabolic homeostasis/pathways may prevent the occurrence and development of diabetic PD.
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Objective To investigate the protective effect and mechanism of liraglutide on the paraquat (PQ)⁃ induced Parkinson's disease (PD) mouse model. Methods Totally 24 Kunming mice were randomly divided into control group, PQ group and PQ +liraglutide group, 8 mice in each group. PD model was established by intraperitoneal injection of PQ (10 mg/kg) for 5 consecutive days, and liraglutide (50 nmol/kg) was injected intraperitoneally for 7 consecutive days. The free⁃standing and locomotor activity of mice were measured by behavioral method. Immunofluorescence was used to observe the number of tyrosine hydroxylase (TH) and ionized calcium binding adaptor molecule 1 (Iba1) immunoreactive cells. Western blotting was used to detect the expression of protein TH, glial fibrillary acidic protein (GFAP), mitofusin⁃2 (Mfn2) and dynamin⁃related protein 1 (Drp1). Results The numbers of free⁃standing and locomotor activity numbers decreased significantly (P<0.01, P < 0.05) in PQ group compared with the control group, and the number of TH immunoreactive cells and TH protein expression in substantia nigra decreased significantly (P<0.01, P<0.01) compared with the control group, while the number of Iba1 immunoreactive cells and GFAP protein expression increased significantly (P<0.01, P<0.01) compared with the control group; the expression of Drp1 protein in PQ group was significantly higher than that in control group (P<0.05), while the Mfn2 protein expression decreased significantly (P<0.05) compared with the control group. After treatment with liraglutide, the number of TH positive cells in PQ + liraglutide group was significantly lower than that in control group (P<0.05); the numbers of free⁃standing and locomotor activity increased significantly (P<0.05, P<0.05) in PQ + liraglutide group compared with the PQ group, and the number of TH positive cells and expression of TH protein in PQ + liraglutide group were significantly higher than that in PQ group (P<0.01, P< 0.01); while the number of Iba1 positive cells and GFAP protein expression decreased significantly (P<0.01, P<0.05) compared with the PQ group; the Drp1 protein expression decreased significantly (P<0.01) compared with the PQ group, while the expression of Mfn2 protein in PQ + liraglutide group was significantly higher than that in PQ group (P<0.01). Conclusion Liraglutide has neuroprotective effect by reducing neuroinflammation in substantia nigra, regulating mitochondrial fusion and fission.
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Objective:To investigate the dynamic changes of mitochondrial fission and fusion in the heart of cardiac arrest (CA) rats after return of spontaneous circulation (ROSC), and to explore the role of mitochondrial fission and fusion in the myocardial injury after ROSC.Methods:Healthy male SD rats were randomly random number assigned into the post-resuscitation (PR) 4 h ( n=12), PR 24 h ( n=12), PR 72 h ( n=12), and sham groups ( n=6). The rat CA model was induced by asphyxia, and cardiopulmonary resuscitation (CPR) was performed 6 min after CA. The protein expressions of mitochondrial Drp1, Fis1, Mfn1, and Opa1 were determined by Western blot in each group at 4, 24 and 72 h after ROSC. The mRNA expressions of Drp1, Fis1, Mfn1, and Opa1 were determined by RT-PCR. Myocardial ATP content and mitochondrial respiratory function were measured. The histopathologic changes of myocardial tissue were observed under light microscope. One-way analysis of variance (ANOVA) was use to compare quantitative data, and LSD- t test was used for comparison between groups. Results:Compared with the sham group, the protein and mRNA expressions of Drp1 and Fis1 were increased (all P<0.05) and the protein and mRNA expressions of Mfn1 and Opa1 were decreased (all P<0.05) in the PR 4 h and PR 24 h groups. However, there were no statistical differences in the protein and mRNA expressions of Drp1, Fis1, Mfn1, and Opa1 in the PR 72 h group compared with the sham group (all P>0.05). Compared with the sham group, the levels of ATP content [(4.53±0.76) nmol/g protein vs. (8.57±0.44) nmol/g protein and (5.58±0.58) nmol/g protein vs. (8.57±0.44) nmol/g protein] and mitochondrial respiratory control rate [(2.47±0.38) vs. (3.45±0.32) and (2.97±0.24) vs. (3.45±0.32)] were obviously decreased in the PR 4 h and PR 24 h groups (all P<0.05). There were no statistically significant differences in the ATP content [(7.73±0.95) nmol/g protein vs. (8.57±0.44) nmol/g protein] and mitochondrial respiratory control ratio [(3.39±0.34) vs. (3.45±0.32)] between the PR 72 h group and the sham group (all P>0.05). The pathological damage of myocardial tissue was obvious in the PR 4 h group, and was improved significantly in the PR 72 h group. Conclusions:The imbalance of mitochondrial fission and fusion is probably involved in the pathological process of myocardial injury after ROSC, which may be related to mitochondrial dysfunction.
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Aim To investigate the damage degree of doxorubicin hydrochloride( DOX )on cardiac function in rats, and to explore its possible mechanism. Methods Experiment 1: SD rats( n=48 )were randomly divided into control group( normal saline ), DOX 1 group( DOX cumulative dose 12 mg·kg-1 ;intraperitoneal injection ), DOX 2 group( 15 mg·kg-1 ;)and DOX 3 group( 18 mg·kg-1 ;). Cardiac structure and cardiac function were detected by echocardiography. B-type natriuretic peptide( BNP )was detected by ELISA. The morphological changes of myocardium were observed by Hematoxylin-eosin( HE )staining. The optimal dose group( DOX 2 group )was selected comprehensively. Experiment 2: SD rats( n=36 )were randomly divided into control group( normal saline ), DOX 2 group(15 mg·kg-1)and DOX 2+Mdivi-1 group( 15 mg·kg-1+daily abdominal injection of Mdivi-1(1 mg ·kg-1 ;)). Western blot was used to detect the protein expression of myocardial mitochondrial dynamics. Results Compared with the control group, hearts in DOX groups were enlarged and the heart function was reduced. Under the microscope, hypertrophy of cardiac cells and loose arrangement of cardiac fibers were observed in DOX group, and the higher the cumulative dose of DOX in rats, the more severe the degree of heart failure and the higher the mortality rate of rats. Compared with control group, the expression of mitochondrial dynamin-related protein 1( DRP1 )and related signaling pathway protein FUN14 domain containing 1( FUNDC1 )in DOX 2 group increased. The expression of optic atrophy 1( OPA1 )decreased, the expression of FUNDC1 and DRP1 protein decreased, and the expression of OPA1 protein was enhanced after the use of mitochondrial dynamics inhibitor(Mdivi-1). Conclusions DOX can cause chronic heart failure, and the mechanism may be related to DRP1/FUNDC1 mediated mitochondrial fission and fusion.
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Mitochondria is one of the important organelles, which is composed of outer mitochondrial membrane and inner mitochondrial membrane. Mitochondrial structure and function are regulated by mitochondrial dynamics. Mitochondrial fusion- and fission-related proteins may participate in the process of mitochondrial fusion and fission, mediate mitochondrial dynamics, thereby regulating cell structure, function and energy metabolism. Mitofusin (MFN) 2, a protein located on the outer mitochondrial membrane of mammalian, has guanosine triphosphatase activity, which may mediate mitochondrial fusion, participate in mitophagy, formation of mitochondria-associated endoplasmic reticulum membrane and apoptosis, and significantly affect the incidence and development of ischemia-reperfusion injury (IRI). In this article, the structure, regulation, function of MFN2 and its role in IRI were reviewed, and the relationship between MFN2 and IRI and underlying mechanism were investigated, aiming to provide novel targets and ideas for the prevention and treatment of IRI.
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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.
Subject(s)
Animals , Rabbits , Hindlimb/metabolism , Mitochondria/metabolism , Mitochondrial Dynamics , Mitochondrial Proteins/pharmacology , Muscle, Skeletal , Vibration/adverse effectsABSTRACT
Ischemia-reperfusion injury (IRI) is one of the main causes of early graft dysfunction after renal transplantation. In China, organ transplantation has entered into the era of organ donation after citizen's death. The increased risk of cardiopulmonary resuscitation, prolonged hypoperfusion time and warm ischemia time of donors may lead to IRI of the graft, and affect the short- and long-term clinical prognosis of the recipient and graft. Under IRI and other stress conditions, the mechanism of mitochondrial dynamics, mainly manifested by dynamic regulation of mitochondrial division and fusion, exert critical effect upon the biological function of mitochondria. Cell apoptosis caused by mitochondrial injury is the key event leading to acute kidney injury, which is mainly manifested by the imbalance of the regulatory mechanism of mitochondrial dynamics. In this article, the research progress on the regulatory mechanism of mitochondrial dynamics on renal IRI was reviewed, aiming to provide reference for improving the clinical outcomes of renal transplantation.
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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
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Animals , Rats , Adiponectin/genetics , Hypoxia , Islets of Langerhans , Mitochondrial Dynamics , Rats, WistarABSTRACT
Objective::To analysis the effect of Huayu Qutan recipe on myocardial fibrosis in atherosclerotic rabbits based on mitochondrial fusion-lysis. Method::The 36 SPF healthy male rabbits were selected, and 6 rabbits were selected randomly as the normal group, and given normal pellet feed, another 30 rats were fed with high fat diet to establish atherosclerosis model.After successful replication of animal models, they were randomly divided into model group, Huayu Qutan recipe low-dose, medium-dose and high-dose group (4.0, 8.0, 16.0 g·kg-1) and simvastatin group (1.4 mg·kg-1), 6 rats each.Each group was given corresponding drugs according to the dosage, continuous administration for 4 weeks.The serum lipid levels in rabbits of each group were detectived by automatic biochemical analyzer, the degree of myocardial fibrosis was measured by Masson staining, and expression levels of mitochondrial fusion protein 1 (Mitofusin 1), mitochondrial fusion protein 2 (Mitofusin 2), optic atrophy protein 1 (Opa1), promoter protein 1 (Drp1), mitogen 1 (Fis1) in myocardial tissue were detected by immunohistochemistry. Result::Compared with normal group, the levels of total cholesterol (TC), triglyceride (TG), low density lipoprotein cholesterol (LDL-C) in model group were significantly increased, levels of density lipoprotein cholesterol (HDL-C) were significantly decreased, the expression levels of Mitofusin 1, Mitofusin 2 and Opa1 in myocardial tissue were significantly decreased, the expression levels of Drp1 and Fis1 were significantly increased(P<0.05, P<0.01), compared with model group, the levels of serum TC, TG, LDL-C in simvastatin group and Huayu Qutan recipe low-dose, medium and high-dose group were significantly decreased, levels of HDL-C were significantly increased, the expression levels of Mitofusin 1, Mitofusin 2 and Opa1 in myocardial tissue were significantly increased, the expression levels of Drp1 and Fis1 were significantly decreased (P<0.05, P<0.01), compared with the Huayu Qutan recipe high-dose group, the levels of serum TC, TG, LDL-C in simvastatin group and Huayu Qutan recipe low, medium-dose group were significantly increased, the expression levels of Mitofusin 1, Mitofusin 2 and Opa1 in myocardial tissue were significantly decreased, the expression levels of Drp1 and Fis1 were significantly increased(P<0.05, P<0.01). Conclusion::Huayu Qutan recipe can effectively regulate blood lipid and inhibit myocardial fibrosis in atherosclerotic rabbits, and the higher the dose of Huayu Qutan recipe, the more obvious the effect is, it is speculated that its effect may be related to the regulation of the expression of mitochondrial fusion-lysis related proteins such as Mitofusin1, Mitofusin2 and Opa1, Drp1 and Fis1 in myocardial cells.
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BACKGROUND: Excessive exercises cause a large accumulation of oxidative active substances in the body to damage skeletal muscle cells. Mitochondria play a key role in energy metabolism during exercise. Studies have shown that Rhodiola can reduce the level of lipid peroxidation in muscle tissue and protect damaged endothelial cells. OBJECTIVE: To explore the mechanism underlying Rhodiola improving skeletal muscle function of mice with high intensity exercise by regulating mitochondrial function. METHODS: The study protocol was approved by the Ethics Committee of Xi’an Shiyou University in China. Forty BALB/c mice were divided into blank control group, exercise group, Rhodiola control group and Rhodiola intervention group. Mice in the blank control had no exercise and intervention. Mice in exercise group were given intragastric administration of normal saline followed by high intensity exercise. Mice in Rhodiola intervention group and Rhodiola control group were given intragastric administration of the mixture of Rhodiola and normal saline, followed by exercise or not. The interventions were performed once a day for 28 consecutive days. Body mass, forearm grip strength and exhaustion time were observed. Western blot assay was used to detect expression of manganese superoxide dismutase protein, p53 protein, mitochondrial origin and autophagy-associated protein in the skeletal muscle. RT-qPCR was used to detect skeletal muscle Mfn-1, Mfn-2, Opa-1, Drp-1, and fis-1 mRNA expression. RESULTS AND CONCLUSION: (1) From the 2nd week, the grip strength of forelimbs in the exercise group was significantly lower than that in the other three groups (P 0.05). (2) At the 3rd and 4th weeks, the exhaustion time of weight-bearing swimming training was significantly shorter in the exercise group than the Rhodiola intervention group (P 0.05). Compared with the blank control group, the Rhodiola exercise intervention group also showed a downward trend in the expression of fusion gene and an upward trend in the expression of Drp-1 mRNA, but there was no significant difference between the two groups (P > 0.05). To conclude, Rhodiola can significantly improve the exercise endurance of mice with high intensity exercise, which may be related to the improvement of skeletal muscle mitochondrial autophagy, origin and fusion-division.
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OBJECTIVE@#To investigate the protective effects of dexmedetomidine (DEX) against cerebral ischemia/reperfusion (I/R) injury in mice and its relation with mitochondrial fusion and fission.@*METHODS@#Male ICR mice were randomly divided into sham-operated group, I/R group, I/R+DEX group and I/R+DEX+dorsomorphin group. Mouse models of cerebral I/R injury were established by modified thread occlusion of the middle cerebral artery. DEX (50 μg/kg) was injected intraperitoneally at 30 min before cerebral ischemia, which lasted for 1 h followed by reperfusion for 24 h. The neurobehavioral deficits of the mice were evaluated based on Longa's scores. The volume of cerebral infarction was detected by TTC staining. The changes in mitochondrial morphology of the brain cells were observed with transmission electron microscopy. Western blotting was performed to detect the expressions of phosphorylated AMP-activated protein kinase (p-AMPK), mitochondrial fusion protein (Mfn2) and mitochondrial fission protein (p-Drp1) in the brain tissues.@*RESULTS@#DEX pretreatment significantly reduced the neurobehavioral score and the percent volume of cerebral infarction in mice with cerebral I/R injury. Treatment with dorsomorphin (an AMPK inhibitor) in addition to DEX significantly increased the neurobehavioral score and the percent volume of cerebral infarction in the mouse models. Transmission electron microscopy showed that DEX obviously reduced mitochondrial damage caused by cerebral I/R injury and restored mitochondrial morphology of the brain cells, and such effects were abolished by dorsomorphin treatment. Western blotting showed that DEX pretreatment significantly increased the expressions of p-AMPK and Mfn2 protein and decreased the expression of p-Drp1 protein in the brain tissue of the mice, and these changes were also reversed by dorsomorphin treatment.@*CONCLUSIONS@#Preconditioning with DEX produces protective effects against cerebral I/R injury in mice possibly by activating AMPK signaling to regulate mitochondrial fusion and fission in the brain cells.
Subject(s)
Animals , Male , Mice , Brain Ischemia , Dexmedetomidine , Mice, Inbred ICR , Mitochondrial Dynamics , Reperfusion InjuryABSTRACT
Objective Melanoma is a malignant tumor with high clinical malignancy, rapid progression, poor prognosis and high mortality. It is of great clinical significance to explore the molecular mechanism of high metastasis of melanoma and find new tumor markers and therapeutic targets. The expression of mitochondrial fusion protein-2 (MFN2) in cutaneous melanoma tissues and peritumoral tissues was studied, and its correlation with clinical parameters was analyzed. The correlation between MFN2 and the biological behavior of melanoma was also discussed. Methods Immunohistochemistry was used to detect the expression of Med19 protein in cutaneous melanoma tissues and peritumoral tissues, and to analyze the correlation between MFN2 expression and clinical factors in patients. The lentiviral vector containing MFN2 coding sequence (Lenti-MFN2) infected with melanoma cell B16 was set up as the study group, and the lentivirus with green fluorescent protein gene (Lenti-GFP) as the control group. The mRNA and protein expressions of MFN2 and Ras-Raf1-ERK1/2 signaling pathways in transfected cells were detected by real-time quantitative PCR (qRT-PCR) and Western blot. Flow cytometry was used to detect changes in cell cycle and apoptosis. MTT assay and colony formation assay were used to detect changes in cell viability and proliferation capacity. Results The positive expression rate of MFN2 in peritumoral tissues was significantly higher than that in the skin melanoma tissues (83.9% vs 30.6%, P<0.05). MFN2 expression was associated with both lymph node metastasis and TNM staging (P<0.05). Compared with the control group, the proliferation activity and colony forming ability of B16 cells in the study group were significantly inhibited (P<0.05); the proportion of G0/G1 phase cells in B16 cells in the study group significantly increased [(46.3±10.3)% vs (67.9±12.6)%], and the apoptosis rate significantly increased [(12.5±1.6)% vs (57.4±12.6)%], with statistically significant differences (P<0.05). In comparison with the control group, the expression of Ras, Raf, ERK1/2 mRNA and protein in the study group significantly decreased (P<0.05). Conclusion MFN2 is down-regulated in melanoma tissues. Up-regulation of MFN2 expression can inhibit melanoma proliferation and promote cell apoptosis, which may be related to the inhibition of Ras-MAPK signaling pathway activity.
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Objective To evaluate the role of protein kinase Cα (PKCoα)/heme oxygenase-1 (HO-1) signaling pathway in lipopolysaccharide (LPS)-caused damage to type Ⅱ alveolar epithelial cells of rats and the relationship with mitochondrial fusion.Methods Type Ⅱ alveolar epithelial cells were seeded in 96-well plates at a density of 2× 105 cells/ml and divided into 5 groups (n =40 each) using a random number table method:control group (group C),Go6976 group (group G),LPS group (group L),LPS plus PKCα inhibitor Go6976 group (group LG) and LPS plus dimethyl sulfoxide (DMSO) group (group LD).Group LG and group LD were pretreated with 5 μmol/L Go6976 and the equal volume of 0.1％ DMSO,respectively,for 30 min,lipopolysaccharide (LPS) 10 μg/ml was then given to establish the model of type Ⅱ alveolar epithelial cell damage in L,LG and LD groups,Go6976 5 μmol/L was added in group G,and the equal volume of phosphate buffer solution was added in group C.The cells were collected after 24 h of incubation for measurement of malondialdehyde (MDA) and reactive oxygen species (ROS) contents,superoxide dismutase (SOD) activity and expression of PKCα,HO-1,mitochondrial fusion-related proteins 1 and 2 (Mfn1,Mfn2),optic atrophy 1 (OPA1) protein and mRNA (by fluorescent quantitative polymerase chain reaction or Western blot).Results Compared with group C,MDA and ROS contents were significantly increased,the SOD activity was decreased,the expression of PKCα and HO-1 protein and mRNA was up-regulated,and the expression of Mfn1,Mfn2 and OPA1 protein and mRNA was downregulated in L,LG and LD groups (P＜0.05),and no significant change was found in the parameters mentioned above in group G (P＞0.05).Compared with group L,MDA and ROS contents were significantly increased,the SOD activity was decreased,and the expression of PKCα,HO-1,Mfn1,Mfn2 and OPA1 protein and mRNA was down-regulated in group LG (P＜0.05),and no significant change was found in the parameters mentioned above in group LD (P＞0.05).Conclusion Activation of PKCα/HO-1 signaling pathway is the endogenous protective mechanism of LPS-caused damage to type Ⅱ alveolar epithelial cells,which may be related to promoting mitochondrial fusion in rats.
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Hypertonia is a neurological dysfunction associated with a number of central nervous system disorders, including cerebral palsy, Parkinson's disease, dystonia, and epilepsy. Genetic studies have identified a homozygous truncation mutation in Trak1 that causes hypertonia in mice. Moreover, elevated Trak1 protein expression is associated with several types of cancers and variants in Trak1 are linked to childhood absence epilepsy in humans. Despite the importance of Trak1 in health and disease, the mechanisms of Trak1 action remain unclear and the pathogenic effects of Trak1 mutation are unknown. Here we report that Trak1 has a crucial function in regulation of mitochondrial fusion. Depletion of Trak1 inhibits mitochondrial fusion, resulting in mitochondrial fragmentation, whereas overexpression of Trak1 elongates and enlarges mitochondria. Our analyses revealed that Trak1 interacts and colocalizes with mitofusins on the outer mitochondrial membrane and functions with mitofusins to promote mitochondrial tethering and fusion. Furthermore, Trak1 is required for stress-induced mitochondrial hyperfusion and pro-survival response. We found that hypertonia-associated mutation impairs Trak1 mitochondrial localization and its ability to facilitate mitochondrial tethering and fusion. Our findings uncover a novel function of Trak1 as a regulator of mitochondrial fusion and provide evidence linking dysregulated mitochondrial dynamics to hypertonia pathogenesis.
Subject(s)
Animals , Humans , Mice , Adaptor Proteins, Vesicular Transport , Metabolism , HeLa Cells , Membrane Fusion , Mitochondria , Metabolism , Mitochondrial Proteins , Metabolism , Muscle Proteins , Metabolism , Tumor Cells, CulturedABSTRACT
Objective To investigate the role of silent mating type information regulation 2 homolog 1(SIRT-1) in lipopolysaccharide (LPS)-induced mitochondrial injury on INS-1(insulinoma cell lines-1)cells. Methods INS-1 cells were divided into 5 groups: control group, 1 mg/L LPS group, LPS group with 10 μmol/L RSV (resveratrol) pretreatment for 1 h, LPS group with 20 μmol/L EX527 pretreatment for 1 h, LPS group together with EX527 pretreatment for 1 h, then incubated these INS-1 cells with RSV and LPS for 24 h. The cell viability and ATP generation were detected, then total, cytoplasmic and mitochondrial protein were isolated from INS-1 cells. The protein expression of SIRT1, TLR4, acetylated FoxO1, and cytochrome C (CytC), Mfn1 (mitofusion1), Mfn2 (mitofusion2), and Fis1 (fission1) were tested by Western-blot. Mfn1, Mfn2, and Fis1 genes expression were detected by real-time PCR. The comparison of multiple groups was performed by one-way ANOVA. LSD-t method was used to compare between every two groups. Results After 1 mg/L LPS stimulation for 24 h, there was decreased cell viability (n=4, F=13.98, P<0.01) and ATP generation (n=4, F=27.92, P<0.05) in INS-1 cells. RSV pretreatment could maintain ATP production, but it could not reverse the EX527-induced ATP decrease (P>0.05). Furthermore, RSV upregulated gene and protein expression of SIRT1, Mfn1 and Mfn2, whereas decreased TLR4 and Fis1 expression. LPS-induced CytC released to cytoplasm was alleviated by RSV (P<0.01), but there was no significant change about FoxO1 protein expression (P>0.05). Conclusions RSV may regulate FoxO1 acetylation followed by its effects on SIRT1 activity, which may be partly the mechanism of mitochondrial damage induced by LPS on INS-1 cells.
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Objective To evaluate the effect of electroacupuncture (EA) on mitochondrial fusionfission during endotoxin-induced acute lung injury (ALI) in rabbits.Methods Sixty clean-grade New Zealand white rabbits,aged 2 months,weighing 1.5-2.0 kg,were divided into 4 groups (n=15 each) using a random number table:control group (group C),ALI group,EA at non-acupoint plus ALI group (group SEAM+ALI) and EA at acupoint plus ALI group (group EAM+ALI).Endotoxin-induced ALI was induced by injecting lipopolysaccharide 5 mg/kg (in 2 ml of 0.9％ normal saline) via the auricular vein in ALI,SEAM+ALI and EAM+ALI groups.At 4,3,2 and 1 days and 30 min before lipopolysaccharide injection,bilateral Zusanli (ST36) and Feishu (BL13) acupoints were stimulated with an electric stimulator for 30 min in group EAM+ALI,and EA was performed for 30 min at the points 1 cm lateral to the acupoints of Zusanli and Feishu in group SEAM+ALI.The animals were sacrificed at 6 h after lipopolysaccharide injection and the lungs were removed for microscopic examination of the pathological changes (with a light microscope) and mitochondrial ultrastructure (with an electron microscope) and for determination of ROS and ATP contents and expression of Mfn1,Mfn2,optic atrophy 1 (OPA1) and dynamin-related protein 1 (Drp1) protein and mRNA in lung tissues (by real-time polymerase chain reaction or Western blot).Results Compared with group C,ATP content was significantly decreased,ROS content was increased,the expression of Mfn1,Mfn2 and OPA1 protein and mRNA was down-regulated,and the expression of Drp1 protein and mRNA was up-regulated in ALI,SEAM +ALI and EAM +ALI groups (P＜ 0.05).Compared with group ALI,ATP content was significantly increased,the expression of Mfn1,Mfn2 and OPA1 protein and mRNA was up-regulated,and the expression of Drp1 protein and mRNA was down-regulated in SEAM+ ALI and EAM+ALI groups,and ROS content was decreased in group EAM+ALI (P＜0.05).Compared with group SEAM+ALI,ATP content was significantly increased,ROS content was decreased,the expression of Mfn1,Mfn2 and OPA1 protein and mRNA was up-regulated,and the expression of Drp1 protein and mRNA was down-regulated in group EAM+ALI (P＜0.05).Conclusion The mechanism by which EA mitigates endotoxin-induced ALI may be related to promoting mitochondrial fusion and inhibiting mitochondrial fission in rabbits.
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Objective To investigate the effects of heme oxygenase-1/carbon monoxide (HO-1/CO) pathway on mitochondrial fusion in rat alveolar epithelial type Ⅱ cells (AECⅡ) stimulated by lipopolysaccharide (LPS). Methods Once the cultured in vitro rat AECⅡcells line RLE-6TN reached confluency of 85%, they were subcultured and randomly divided into seven groups (n = 5 each). RLE-6TN cells were routinely cultured in control group. The cells in LPS group was stimulated with 10 mg/L LPS to reproduce the model of endotoxin challenge in AECⅡ cells. The cells in carbon monoxide-releasing molecule-2 (CORM-2, in vitro CO release agent) + LPS group (CL group) and Hemin (HO-1 inducer) + LPS group (HL group) were pretreated with 100 μmol/L CORM-2 or 20 μmol/L Hemin for 1 hour, respectively, followed by 10 mg/L LPS stimulation. The cells in zinc protoporphyrin-Ⅸ (ZnPP-Ⅸ, HO-1 inhibitor) + LPS group (ZL group) was pretreated with 10 μmol/L ZnPP-Ⅸ for 0.5 hour followed by 10 mg/L LPS stimulation. The cells in CORM-2 + ZnPP-Ⅸ + LPS group (CZL group) and Hemin + ZnPP-Ⅸ + LPS group (HZL group) were pretreated with 100 μmol/L CORM-2 or 20 μmol/L Hemin respectively for 1 hour, and other treatments were similar to those previously described in ZL group. At 24 hours after LPS stimulation, interleukin-6 (IL-6)and tumor necrosis factor-α (TNF-α) in the supernatant were determined by enzyme linked immunosorbent assay (ELISA), the protein expressions of HO-1, mitochondrial fusion related proteins 1 and 2 (Mfn1, Mfn2) and optic atrophy 1 (OPA1) were determined by Western Blot. Results Compared with control group, IL-6 and TNF-α contents in the supernatant were increased, HO-1 protein expression was up-regulated, Mfn1, Mfn2 and OPA1 protein expressions were down-regulated in all treatment groups. Compared with LPS group, IL-6 and TNF-α contents were significantly decreased after CORM-2 or Hemin pretreatment [IL-6 (ng/L): 48.6±3.7, 48.4±3.1 vs. 58.7±2.5; TNF-α (ng/L):40.7±5.3, 39.4±4.3 vs. 51.8±5.1], the protein expressions of HO-1, Mfn1, Mfn2 and OPA1 were significantly up-regulated (HO-1 protein: 0.873±0.051, 0.839±0.061 vs. 0.671±0.044; Mfn1 protein: 0.673±0.037, 0.654±0.025 vs. 0.568±0.021; Mfn2 protein: 0.676±0.044, 0.683±0.035 vs. 0.571±0.043; OPA1 protein: 0.648±0.031, 0.632±0.031 vs. 0.554±0.032; all P < 0.05); while opposite effects were found after ZnPP-Ⅸ preincubation, and there were significant differences in IL-6 and TNF-α contents and protein expressions of HO-1, Mfn1, Mfn2 and OPA1 as compared with those of LPS group [IL-6 (ng/L): 69.8±5.1 vs. 58.7±2.5, TNF-α (ng/L): 61.9±3.3 vs. 51.8±5.1, HO-1 protein: 0.545±0.023 vs. 0.671±0.044, Mfn1 protein: 0.406±0.051 vs. 0.568±0.021, Mfn2 protein:0.393±0.051 vs. 0.571±0.043, OPA1 protein: 0.372±0.050 vs. 0.554±0.032; all P < 0.05]. There were no significant differences in the parameters mentioned above between HL group and CL group, as well as among LPS, CZL and HZL groups. Conclusion HO-1/CO pathway promotes mitochondrial fusion and alleviates inflammatory response in LPS-induced rat AECⅡ cells.