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Objective To investigate the effects of harmine(HM)on the expression level of mitochondrion fusion related proteins and mitochondrial function injury in PC 12 cells.Methods PC 12 cells were divided into cell control group,HM group,mitochondrion mitosis inhibitor Mdivi-1 group,HM+Mdivi-1 group,mitochondrion fission agonist WY14643 group,HM+WY14643 group,with drug concentrations of 1,10,25,50,100 μmol·L-1.After 24 h treatment,the MTT method was used to detect the cell survival rate,and a microscope was used to observe the cell morphology,MitoTracker Red probe staining was used to observe the mitochondrial morphology and the length ratio of vertical and horizontal axes,JC-1 staining was used to detect the mitochondrial membrane potential,and a kit was used to detect ATP level and lactate dehydrogenase(LDH)activity.Immunofluorescence staining and Western blotting were used to assess the expression levels of caspase-3,apoptosis-promoting protein(Bax)cytochrome C(cyt-c),mitochondrial fusion protein(Mfn2)and mitochondrial mitotic protein(Drp-1).The interference sequence of Drp1 was transfected by electroporation,and the siRNA sequence with good transfection effect was screened.The related indicators were detected by fluorescence method,MTT method,and immunoblotting method in cooperation with drug intervention.Results MTT results showed that compared with the cell control group,the survival rate of HM group,Mdivi-1 group,HM+Mdivi-1 group,WY14643 group and HM+WY14643 group decreased significantly(P＜0.01),and the EC50 were(11.48±2.32),(12.35±1.67),(14.88±2.07),(39.14±3.25),(20.09±1.97),respectively.According to this,subsequent experiments selected 20 μmol·L-1for HM,WY 14643 and HM+WY14643 as working concentrations to construct PC 12 cell model.Microscopic observation and MitoTracker Red probe staining showed that the cell density in the drug group decreased in varying degrees,and a transition from branched to round morphology in the drug-treated groups was observed.The morphology of mitochondria tended to be round,and the ratio of the length of the longitudinal axis to transverse axis was(3.33±0.72)in the cell control group,(2.19±0.58)in the HM group,(2.45±0.44)in Mdivi-1 group,and(1.43±0.62)in HM+Mdivi-1 group,respectively.The results of JC-1 staining showed that compared with the cell control group,the mitochondrial mode potential of the HM group significantly decreased(P＜0.01).ROS significantly increased(P＜0.01)and ATP levels decreased(P＜0.01),and LDH enzyme activity increased(P＜0.01).Immunofluorescence staining and Western blotting results showed that compared with the cell control group,the expression levels of proapoptotic proteins Bax,cytochrome C,and caspase-3 in the HM group were significantly increased(all P＜0.01).Compared with the cell control group,the expression level of mitochondrial fission related protein Drp1 in HM group was significantly higher(P＜0.01).The expression level of mitochondrial fusion related protein Mfn2 significantly decreased(P＜0.01).After specific interference with Drp1 and synergistic intervention with HM,the survival rate of PC 12 cells in each interference group decreased compared to each drug intervention group.The expression of Drp1 and Mfn2 was downregulated,and the differences were statistically significant(P＜0.05 or P＜0.01).Conclusion HM can reduce the mitochoudrial membrane potential and ATP levels by accumulating ROS,there by activating the caspase-3 apoptosis pathway and promoting cell apoptosis.Mitochondrial fusion division may be involved in the damage of PC12 cells caused by HM,initiating apoptosis through the mitochondrial pathway.
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AIM:To investigate the therapeutic effect of mitochondrial fission inhibitor-1(Mdivi-1)on experi-mental autoimmune encephalomyelitis(EAE)in mice,and to explore its mechanism.METHODS:The mice immunized with myelin oligodendrocyte glycoprotein peptide fragment 35-55(MOG35-55)were randomly divided into DMSO model group and Mdivi-1 intervention group.All mice were sacrificed on the 28th day after the first immunization.The demyelination was analyzed by Luxol fast blue staining.The protective mechanism of Mdivi-1 in the spinal cord tissue was investigated by immunofluorescence staining,TUNEL staining and the in vitro experiment with MO3.13 oligodendrocytes treated with staurosporine.The mitochondrial depolarization was detected by JC-1 staining,the cell injury was checked by LDH leakage,and the viability of MO3.13 oligodendrocytes was determined by MTT assay.RESULTS:Compared with DMSO model group,the demyelinating injury was alleviated and the proportion of apoptotic CC1+ oligodendrocytes in Mdivi-1 group was decreased.The cleaved caspase-3,caspase-9,cytochrome C and Bax protein expression levels in the spinal cord of Mdivi-1-treated mice was also attenuated.The in vitro MO3.13 cell experiments suggested that Mdivi-1 inhibited MO3.13 cell mitochondrial depolarization,attenuated the cell damage and increased the cell viability.CONCLUSION:Mdivi-1 pro-tects against the myelin injury in EAE mice,which may be related to the suppression of oligodendrocyte apoptosis.
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BACKGROUND:Cardiac hypertrophy is an adaptive response of the heart to physiological and pathological stimuli such as pressure overload.It is of compensatory significance in the early stage,but if the stimulation continues,it can cause cardiomyopathy leading to heart failure.MicroRNAs are involved in the regulation of cardiac hypertrophy.However,the role of miR-20a in pressure overload-induced cardiac hypertrophy has not been reported. OBJECTIVE:To investigate the role of miR-20a in pressure overload-induced cardiac hypertrophy and the underlying mechanisms. METHODS:Transverse aortic constriction was used to induce cardiac hypertrophy in vivo and angiotensin Ⅱ was used to induce H9c2 cell models of cardiac hypertrophy in vitro.MiR-20a was overexpressed in vivo by intramyocardial injection of miR-20a overexpressing adenovirus and in vitro by transfecting miR-20a mimic into H9c2 cells.Cardiac hypertrophy was assessed by measuring heart weight/body weight ratio,cell surface area,and myocardial fibrosis.The expression levels of atrial natriuretic peptide,brain natriuretic peptide,β-myosin heavy chain and miR-20a were detected by real-time fluorescence quantitative PCR.Mitochondrial fission was detected by MitoTracker.The downstream target genes of miR-20a were predicted by RNAhybrid software. RESULTS AND CONCLUSION:(1)The expression level of miR-20a was significantly decreased in both hypertrophic cardiomyocytes and hearts(P<0.05).(2)At the animal level,overexpression of miR-20a significantly inhibited transverse aortic constriction-induced cardiac hypertrophy,including decreasing the upregulated expression level of hypertrophic marker genes(P<0.05),reduced the enlarged heart volume,reducing the increased heart weight/body weight ratio(P<0.01),reducing the increased myocardial cross-sectional area(P<0.05),and attenuating fibrosis(P<0.01).(3)At the cellular level,overexpression of miR-20a significantly inhibited angiotensin Ⅱ-induced cardiomyocyte hypertrophy,including decreasing the upregulated expression levels of atrial natriuretic peptide(P<0.05),brain natriuretic peptide(P<0.01)and β-myosin heavy chain(P<0.05),reducing the increased protein/DNA ratio(P<0.01),and suppressing the increased cell surface area(P<0.05).(4)Overexpression of miR-20a significantly inhibited angiotensin Ⅱ-induced mitochondrial fission(P<0.05).(5)The results of RNAhybrid software analysis showed that miR-20a and the mRNA 3'untranslated region of cAMP-dependent protein kinase inhibitor alpha were well complementary and the predicted binding sites were highly conserved.(6)In conclusion,miR-20a is significantly down-regulated in pressure overload-induced cardiac hypertrophy.Overexpression of miR-20a inhibits cardiac hypertrophy at both the cellular level and animal level and attenuates angiotensin Ⅱ-induced mitochondrial fission.
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BACKGROUND:Mitochondrial quality control is a complex process,which involves three aspects:mitochondrial biogenesis,mitochondrial dynamics change and mitochondrial autophagy,among which mitochondrial dynamics change is the intermediate link between mitochondrial biogenesis and mitochondrial autophagy.Mitochondria can improve their own quality control through dynamics change and then maintain their stable state. OBJECTIVE:To explore the molecular mechanism underlying the influence of exercise on mitochondrial dynamics,so as to provide theoretical basis for improving mitochondrial network homeostasis and promoting functional health. METHODS:Using the method of literature review,CNKI,Bailianyun Library,PubMed,Web of Science,EBCSO were searched for relevant literature with the keywords of"Exercise,Mitochondrial Steady State,Mitochondrial Quality Control,Mitochondrial Dynamics,Mitochondrial Fusion and Mitochondrial Division"in Chinese and English.The finally obtained literature was screened,read,and summarized. RESULTS AND CONCLUSION:Dynamin-related proteins 1/2 are responsible for mitochondrial fission,while mitofusins 1/2 and optic atrophy type 1 mediate the fusion of outer membrane and inner mitochondrial membranes respectively.Exercise training can improve the function of mitochondria by up-regulating the protein expression of mitofusins 1/2 and optic atrophy type 1 and down-regulating the protein expression level of dynamin-related protein 1,promoting mitochondrial fusion and inhibiting mitochondrial fission.The findings that a single acute exercise affects changes in mitochondrial dynamics are controversial.Furthermore,there is tissue variability in exercise-mediated changes in mitochondrial dynamics.
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ObjectiveTo investigate the effects of Linggui Zhugantang on mitochondrial fission and fusion and silencing information regulator 3（Sirt3）/adenosine monophosphate dependent protein kinase （AMPK） signaling pathway in chronic heart failure （CHF） rats after myocardial infarction （MI）. MethodSD rats randomly divide into sham operation group （normal saline ，thread only without ligature）， model group （normal saline， ligation of the left anterior descending coronary artery proximal to the heart）， Linggui Zhugantang group （4.8 g·kg-1） and Captopril group （0.002 57 g·kg-1）， with 10 rats in each group. Administere drug continuously for 28 days. Echocardiography detected cardiac function parameters. Hematoxylin eosin （HE） staining observed the pathological changes of the heart. Immunofluorescence detected the levels of reactive oxygen species （ROS）. JC-1 detect mitochondrial membrane potential. Colorimetry measure adenosine triphosphate （ATP）， superoxide dismutase （SOD）， malondialdehyde （MDA）， mitochondrial respiratory chain complex activity （Ⅰ-Ⅳ）. TdT-mediated dUTP nick end labeling （TUNEL） staining detected the apoptosis rate of myocardial tissue. Western blot detected protein expression levels of Sirt3， phosphorylated AMPK （p-AMPK）， phosphorylated dynamic-related protein 1（p-Drp1）， mitochondrial fission protein 1（Fis1）， mitochondrial fission factor （MFF）， optic atrophy protein 1（OPA1）. ResultCompared to the sham group， the left ventricular end diastolic diameter （LVIDd） and left ventricular end systolic diameter （LVIDs） were significantly increased in model group （P<0.01）， while the left ventricular short axis shortening rate （LVFS） and left ventricular ejection fraction （LVEF） were significantly decreased （P<0.01）. There were inflammatory cell infiltration and obvious pathological injury in myocardial tissue. ROS， MDA levels and myocardial cell apoptosis rate were significantly increased （P<0.01）， SOD level， ATP content， and membrane potential were significantly decreased （P<0.01）. The activity of mitochondrial respiratory chain complexes （Ⅰ-Ⅳ） was significantly decreased （P<0.01）. Levels of p-Drp1， Fis1， MFF proteins were significantly up-regulated （P<0.01）， while Sirt3， p-AMPK， OPA1 proteins level were significantly down-regulated （P<0.01）. Compared with model group， LVIDd and LVIDs were significantly decreased （P<0.01）， LVEF and LVFS were significantly increased （P<0.01）. Inflammatory cell infiltration and pathological damage of myocardial tissue were significantly relieved. ROS， MDA levels and myocardial cell apoptosis rate were significantly decreased in Linggui Zhugantang group and Captopril group （P<0.01）， SOD level， ATP content， and membrane potential significantly increased （P<0.01）. The activity of mitochondrial respiratory chain complexes （Ⅰ-Ⅳ） increased significantly （P<0.01），and p-Drp1， Fis1， MFF protein levels were significantly down-regulated （P<0.01）， Sirt3， p-AMPK， OPA1 protein were significantly up-regulated （P<0.01）. ConclusionLinggui Zhugantang can alleviate oxidative stress and apoptosis damage of myocardial cells， maintain mitochondrial function stability， and its effect may be related to mitochondrial mitosis fusion and Sirt3/AMPK signaling pathway.
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ObjectiveTo study the effect and mechanism of Yixintai on mitochondrial fission proteins in the rat model of chronic heart failure. MethodTen of 60 SD rats were randomly selected as the sham operation group， and the remaining 50 rats were subjected to ligation of the left anterior descending coronary artery for the modeling of heart failure post myocardial infarction. The successfully modeled rats were randomized into model， low-， medium-， and high-dose （1.4， 2.8， and 5.6 g·kg-1， respectively） Yixintai， and trimetazidine （10 mg·kg-1） groups. The rats were administrated with corresponding doses of drugs by gavage， and the rats in the model group and sham operation group were given an equal volume of normal saline by gavage for 28 consecutive days. Enzyme-linked immunosorbent assay （ELISA） was then employed to measure the levels of amino-terminal pro-B-type natriuretic peptide （NT-pro BNP）， B-type natriuretic peptide （BNP）， and adenosine triphosphate （ATP） in the serum. Color Doppler ultrasound imaging was conducted to examine the cardiac function indicators. Hematoxylin-eosin staining and Masson staining were conducted to observe the pathological changes in the heart， and Image J was used to calculate collagen volume fraction （CVF）. Transmission electron microscopy was employed to observe the ultrastructural changes of myocardial cells. Terminal-deoxynucleoitidyl transferase-mediated nick-end labeling （TUNEL） was employed to measure the apoptosis rate of myocardial cells. Western blot was employed to determine the protein levels of mitochondrial fission protein 1 （Fis1） and mitochondrial fission factor （Mff） in the outer mitochondrial membrane of the myocardial tissue. ResultCompared with the sham operation group， the model group showed elevated levels of NT-pro BNP and BNP in the serum， decreased ATP content， left ventricular ejection fraction （LVEF）， and left ventricular fraction shortening （LVFS）， increased left ventricular end-diastolic diameter （LVIDd） and left ventricular end-systolic diameter （LVIDs）， disarrangement of myocardial cells， inflammatory cell infiltration， increased collagen fibers and CVF， damaged myocardium and mitochondria， and increased apoptosis rate of myocardial cells， and up-regulated expression of Fis1 and Mff in the cardiac tissue （P<0.01）. Compared with the model group， different doses of Yixintai and trimetazidine lowered the serum levels of NT-pro BNP and BNP （P<0.05）， increased the ATP content （P<0.05）， increased LVEF and LVFS （P<0.01）， decreased LVIDd and LVIDs （P<0.01）. Moreover， the drugs alleviated the myocardial inflammatory damage and fibrosis， reduced CVF （P<0.01）， repaired the myocardial mitochondrial structure， and decreased the apoptosis rate of myocardial cells （P<0.01）. Medium- and high-dose Yixintai and trimetazidine down-regulated the expression of Fis1 and Mff in the myocardial tissue （P<0.05）. ConclusionYixintai can improve mitochondrial structure， reduce myocardial cell apoptosis， and improve cardiac function by inhibiting the expression of Fis1 and Mff in the myocardial tissue.
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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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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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Objective:To evaluate the effect of losartan on acute kidney injury (AKI) and the relationship with mitochondrial fusion-fission in septic mice.Methods:One hundred and twenty-eight SPF male C57BL/6J mice, aged 6-8 weeks, weighing 20-25 g, were divided into 4 groups ( n=32 each) using a random number table method: sham operation group (Sham group), sham operation+ losartan group (Sham+ LOS group), sepsis-associated AKI group (SA-AKI group), and sepsis-associated AKI+ losartan group (SA-AKI+ LOS group). Sepsis was induced by cecal ligation and puncture in anesthetized mice. Sham+ LOS group and SA-AKI+ LOS group received intraperitoneal injection of losartan 5 mg/kg, once a day, for 3 consecutive days, starting from 3 days before sham operation or developing the model. The equal volume of solvent was given instead in Sham group and SA-AKI group. Twenty mice were randomly selected to observe the survival 7 days after surgery. At 24 h after sham operation or establishing the model, serum blood urea nitrogen (BUN) and creatinine (Cr) concentrations were determined by the colorimetric method, and serum concentrations of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6) and high-mobility group box 1 protein (HMGB1) were measured using enzyme-linked immunosorbent assay. Renal tissues were obtained for microscopic examination of pathological changes which were scored and for determination of mitochondrial membrane potential (using JC-1 method) and expression of dynamin-related protein 1 (Drp1) and mitofusin-2 (Mfn2) (using Western blot). Results:Compared with Sham group, the survival rate was significantly decreased, the serum BUN, Cr, TNF-α, IL-6 and HMGB1 concentrations and renal tubular injury score were increased, the ATP content and MMP were decreased, the expression of Drp1 was up-regulated, the expression of Mfn2 was down-regulated ( P<0.05), and pathological changes were found in renal tissues in SA-AKI group and SA-AKI+ LOS group. Compared with SA-AKI group, the survival rate was significantly increased, serum concentrations of BUN, Cr, TNF-α, IL-6 and HMGB1 and renal tubular injury score were decreased, the ATP content and MMP were increased, the expression of Drp1 was down-regulated, the expression of Mfn2 was up-regulated ( P<0.05), and the pathological changes of renal tissues were significantly attenuated in SA-AKI+ LOS group. Conclusions:Losartan can alleviate AKI in septic mice, and the mechanism may be related to promoting mitochondrial fusion and inhibiting mitochondrial fission.
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ObjectiveTo observe the effects of Danggui Buxuetang on the mitochondrial fission and apoptosis of podocytes in the rat model of diabetic kidney disease （DKD） and to explore the protective effect and mechanism of Danggui Buxuetang on DKD rats. MethodSD rats were randomized into a modeling group （n=65， fed with a high-sugar and high-fat diet） and a normal group （n=10， fed with a normal diet）. After 6 weeks， the modeled rats were injected intraperitoneally with streptozotocin （STZ） for the modeling of type 2 diabetes mellitus （T2DM）. Sixty T2DM rats were randomized into model， irbesartan （0.014 g·kg-1）， and low-， medium-， and high-dose （0.36， 0.72， 1.44 g·kg-1， respectively） Danggui Buxuetang groups and administrated with corresponding drugs by gavage for 16 weeks. The levels of fasting blood glucose （FBG） and 24 h urinary protein （24 h UTP） were determined at the end of the 16th week. The pathological changes of the renal tissue were observed by hematoxylin-eosin and Masson staining. The mitochondrial ultrastructure of rat podocytes was observed by transmission electron microscopy. The level of reactive oxygen species （ROS） in the renal tissue of rats was measured by the fluorescent probe labeling of dihydroethidium （DHE）. The apoptosis of renal cells was detected by terminal-deoxynucleotidyl transferase-mediated dUTP nick end labeling （TUNEL）. The expression levels of Synaptopodin， Podocin， and cleaved caspase-3 in renal podocytes were detected by the immunohistochemical method （IHC）. Western blot was employed to determine the protein levels of A-kinase anchoring protein 1 （AKAP1）， phosphorylated dynamin-related protein 1 （p-Drp1）， mitofusin-2 （Mfn2）， B-cell lymphoma-2 （Bcl-2）， and Bcl-2-associated X protein （Bax）. ResultCompared with the control group， the model group showed elevated levels of FBG and 24 h UTP， mesangial hyperplasia， basement membrane thickening， mitochondrial swelling， mitochondrial crista breakage and disorder， and increased ROS and TUNEL-positive cells. In addition， the model group showcased down-regulated expression of Synaptopodin and Podocin， increased expression of cleaved Caspase-3， up-regulated protein levels of AKAP1 and p-Drp1 ， and down-regulated protein levels of Mfn2 and Bcl-2/Bax （P<0.01）. Compared with the model group， high-dose Danggui Buxuetang lowered the levels of FBG and 24 h UTP， alleviated the pathological injuries of the renal tissue and the mitochondrial injury of podocytes， decreased ROS and TUNEL-positive cells， promoted the expression of Synaptopodin and Podocin， inhibited the expression of cleaved Caspase-3， down-regulated the protein levels of AKAP1 and p-Drp1， and up-regulated the protein levels of Mfn2 and Bcl-2/Bax （P<0.05， P<0.01）. ConclusionDanggui Buxuetang may inhibit mitochondrial fission and apoptosis of podocytes and reduce urine protein by regulating the AKAP1/Drp1 pathway， thereby delaying the progression of DKD.
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@#BACKGROUND: Pulmonary fibrosis (PF) is one of the main causes of death in patients with paraquat (PQ) poisoning. This study aimed to evaluate the relationship between mitochondrial fission and oxidative stress in PQ-induced epithelial-mesenchymal transition (EMT) and PF. METHODS: C57BL/6 mice and MLE-12 cells were exposed to PQ to construct a PF model in vivo and in vitro. Histological changes in the lungs were examined by hematoxylin and eosin (H&E) staining. Mitochondrial morphology was detected by MitoTracker® Deep Red FM or transmission electron microscopy (TEM). Western blotting and immunofluorescence were used to determine the expression of protein. The migration ability of the cells was detected by the cell scratch test. Mitochondrial DNA (mtDNA) levels were assessed by real-time polymerase chain reaction (PCR). Enzyme-linked immunosorbent assay (ELISA) was applied to detect cytokine levels. Superoxide dismutase (SOD) activity and the levels of glutathione (GSH) and malondialdehyde (MDA) were detected by chemichromatometry. RESULTS: PQ exposure caused EMT and PF in vivo and in vitro. PQ destroyed mitochondrial structure and enhanced the expression of dynamin-related protein 1 (Drp1), which were accompanied by oxidative stress. Inhibiting mitochondrial fission using mitochondrial division inhibitor-1 (Mdivi-1), a selective inhibitor of Drp1, attenuated PQ-induced EMT and oxidative damage. Treatment with N-acetyl-L-cysteine (NAC), an antioxidant, reduced Drp1 expression, attenuated mitochondrial structure damage and inhibited PQ-induced EMT and PF. Both Mdivi-1 and NAC treatment markedly suppressed mtDNA release, the expression of Toll-like receptor 9 (TLR9) and phosphorylation (P)-NF-κB p65 as well as cytokines (interleukin 6 [IL-6], interleukin-1β [IL-1β], and tumor necrosis factor-α [TNF-α]) production. CONCLUSION: Mutual promotion of mitochondrial fission and oxidative stress contributes to EMT in PQ-induced PF, which is associated with the mtDNA/TLR9/NF-κB pathway.
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Divisions at the periphery and midzone of mitochondria are two fission signatures that determine the fate of mitochondria and cells.Pharmacological induction of excessively asymmetric mitofission-associated cell death(MFAD)by switching the scission position from the mitochondrial midzone to the periphery represents a promising strategy for anticancer therapy.By screening a series of pan-inhibitors,we identified pracinostat,a pan-histone deacetylase(HDAC)inhibitor,as a novel MFAD inducer,that exhibited a significant anticancer effect on colorectal cancer(CRC)in vivo and in vitro.Pracinostat increased the expression of cyclin-dependent kinase 5(CDK5)and induced its acetylation at residue lysine 33,accelerating the formation of complex CDK5/CDK5 regulatory subunit 1 and dynamin-related protein 1(Drp1)-mediated mitochondrial peripheral fission.CRC cells with high level of CDK5(CDK5-high)displayed midzone mitochondrial division that was associated with oncogenic phenotype,but treatment with pracinostat led to a lethal increase in the already-elevated level of CDK5 in the CRC cells.Mechanistically,pracinostat switched the scission position from the mitochondrial midzone to the periphery by improving the binding of Drp1 from mitochondrial fission factor(MFF)to mitochondrial fission 1 protein(FIS1).Thus,our results revealed the anticancer mechanism of HDACi pracinostat in CRC via activating CDK5-Drp1 signaling to cause selective MFAD of those CDK5-high tumor cells,which implicates a new paradigm to develop potential therapeutic strategies for CRC treatment.
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OBJECTIVE@#To investigate the growth-inhibitory and pro-apoptotic effects of piroctone olamine (PO) on glioma cells and explore the underlying mechanism.@*METHODS@#Human glioma cell lines U251 and U373 were treated with PO and the changes in cell proliferation were detected using CCK-8 assay and EdU assay. Clone formation assay and flow cytometry were used to examine the changes in clone formation ability and apoptosis of the treated cells. Mitochondrial membrane potential of the cells and morphological changes of the mitochondria were detected using JC-1 staining and a fluorescence probe, respectively. The expressions of mitochondrial fission protein DRP1 and the fusion protein OPA1 were determined with Western blotting. Transcriptome sequencing and differential gene enrichment analysis was performed, and the expression levels of PI3K, AKT and p-AKT in the treated cells were verified using Western blotting.@*RESULTS@#CCK-8 assay showed that PO significantly inhibited the proliferation of U251 and U373 cells in a time- and dose-dependent manner (P < 0.001). EdU test showed that the proliferative activity of PO-treated cells was significantly decreased, and the number of cell colonies also decreased significantly (P < 0.01). PO treatment significantly increased apoptotic rates (P < 0.01), decreased mitochondrial membrane potential and caused obvious changes in mitochondrial morphology of the cells. Pathway enrichment analysis showed that the down-regulated genes were significantly enriched in the PI3K/AKT pathway, which was verified by Western blotting showing significantly down-regulated expression levels of PI3K, AKT and p-AKT in PO-treated cells (P < 0.05).@*CONCLUSION@#PO interferes with mitochondrial fusion and fission function through the PI3K/AKT pathway, thereby inhibiting the proliferation and increasing apoptosis of glioma cells.
Subject(s)
Humans , Glioma , Mitochondrial Dynamics , Phosphatidylinositol 3-Kinases , Proto-Oncogene Proteins c-aktABSTRACT
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 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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Objective:To investigate whether astaxanthin (AST) down-regulates dynamin-related protein 1 (Drp1) through activating the silent mating type information regulation 2 homolog-1 (SIRT1) signaling pathway, thereby attenuating contrast-induced acute kidney injury.Methods:Forty adult male Sprague-Dawley rats weighing 160-180 g were randomly divided into five groups: sham surgery group (Sham group), contrast medium injury group (CM group), astaxanthin-intervention group (AST+CM group), SIRT1 inhibitor Ex527 intervention group (Ex527+CM group), and astaxanthin combined with Ex527 intervention group (AST+Ex527+CM group). After 72 hours of modeling, heart blood was removed and kidney tissues were collected for follow-up testing. Serum creatinine (Scr), blood urea nitrogen (BUN), and oxidative stress-related indexes total superoxide dismutase (T-SOD) and malondialdehyde (MDA) were measured by biochemistry; hematoxylin and eosin staining was performed to observe the pathological changes in the kidney; mitochondrial morphology and number were observed by transmission electron microscopy; reactive oxygen species (ROS) levels were detected by ROS staining in frozen sections; TUNEL staining was performed to detect apoptosis level. The expression levels of SIRT1, p53, peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α), Drp1 and apoptosis-related proteins Bcl-2 and Bax were detected by Western blotting.Results:(1) Compared with the CM group, Scr and BUN level were significantly lower, T-SOD level was higher and MDA level was lower in the AST+CM group, while T-SOD level decreased and MDA level increased after the combination of Ex527 (all P<0.05). (2) ROS expression was lower in the AST+CM group compared to the CM group and higher after the combination of Ex527 (both P<0.05). (3) The number of apoptotic cells was significantly reduced in the AST+CM group compared to the CM group and increased after the combination of Ex527 (both P<0.05). (4) The protein expression levels of SIRT1, PGC-1α and Bcl-2 were increased and the protein expression levels of p53, Drp1 and Bax were decreased (all P<0.05) in the AST+CM group compared with the CM group, and the protein expression levels of SIRT1, PGC-1α and Bcl-2 were decreased and the protein expression levels of p53, Drp1 and Bax were increased when Ex527 was combined (all P<0.05). Conclusion:Astaxanthin can inhibit Drp1-mediated mitochondrial fission by activating the SIRT1 pathway, thereby reducing contrast-induced acute kidney injury in rats.
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ObjectiveTo investigate the effect of Zishen Huoxue prescription on promoting neurogenesis in hippocampal CA1 region of vascular dementia （VD） rats by regulating mitophagy. MethodThe 2-VO method was used to establish the VD rat model and 60 SD rats were randomly divided into sham operation group， model group， donepezil hydrochloride group， and Zishen Huoxue prescription low-dose（8.9 g·kg-1）， medium-dose（17.8 g·kg-1） and high-dose（35.6 g·kg-1） groups. Morris water maze test was performed to detect the escape latency and the number of crossing platform in each group. The expression of phosphatase and tensin homology-induced kinase 1 （PINK1） and Parkinson protein （Parkin） mRNA in hippocampal CA1 region was detected by Real-time fluorescent quantitative polymerase chain reaction（Real-time PCR）. Western blot was used to determine the expression of mitochondrial autophagy signaling pathway-related proteins Parkin， prohibitin 2 （PHB2）， mitofusin 2 （Mfn2） and dynamin-related protein 1 （Drp1） in hippocampal CA1 region. The neurogenesis in hippocampal CA1 region was tested by Brdu method. ResultCompared with the conditions in the sham operation group， the learning and spatial memory abilities of the model group were decreased （P<0.05）， with damaged mitochondrial structure and autolysosome formation in the hippocampal CA1 region. The expressions of Parkin， Pink1 mRNA and Parkin， PHB2， and Drp1 proteins were up-regulated （P<0.05）， while the expression of Mfn2 protein and the neuronal regeneration in hippocampal CA1 region were reduced （P<0.05， P<0.05）. Compared with the conditions in the model group， Zishen Huoxue prescription enhanced the learning and spatial memory abilities of VD rats （P<0.05）， increased the number of autophagosomes in hippocampal CA1 region and improved the mitochondrial structure. The expression of Parkin， Pink1 mRNA and Parkin， PHB2， and Drp1 proteins in hippocampal CA1 region was up-regulated （P<0.05， P<0.01）while the expression of Mfn2 protein was down-regulated（P<0.05， P<0.01）. The number of new neurons in hippocampal CA1 region was also increased（P<0.05， P<0.01）. ConclusionThe promoting effect of Zishen Huoxue prescription on the neurogenesis in hippocampal CA1 region of VD rats was related to the mitophagy mediated by Pink1/Parkin signaling pathway.
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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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Aim To investigate the effects of DNMT3A regulating Drp1 mediated mitochondrial fission on the proliferation and migration of active hepatic stellate cells. Methods HSC-T6 cells were activated by 5 μg·L-1 TGF-β1 for 24 h, and DNMT3A lentivirus infection model was established to silence DNMT3A. The experiment was divided into control group, TGF-β1 group, TGF-β1+LV5-NC group and TGF-β1+ LV5-DNMT3A group. The effects of DNMT3A on related mRNA and protein expression were detected by RT-qPCR and Western blot. The cell proliferation was detected by CCK-8. The effect of DNMT3A on the migration ability of HSCs cells was observed by Wound healing assay and Transwell migration assay. Results Lentivirus infection successfully constructed a DNMT3A silencing model. Compared with the control group, the level of DNMT3A significantly increased, the mRNA and protein levels of the fibrosis markers collagen and α-SMA in the TGF-β1 group significantly increased, and the mRNA and protein levels of the mitochondrial fission marker Drp1 significantly increased; At the same time, the proliferation and migration ability of HSCs cells was significantly improved. Compared with the NC group, the DNMT3A level of the DNMT3A silenced group was significantly reduced, the expressions of collagen I, α-SMA and Drp1 were significantly inhibited, and the proliferation and migration capabilities of HSCs were also significantly inhibited. Conclusions Silencing DNMT3A inhibits the level of Drp1 and inhibits the proliferation and migration of HSCs at the same time. It is suggested suggest that DNMT3A-mediated low level DNA methylation modification may inhibit the occurrence of mitochondrial fission by inhibiting the level of Drp1, thereby inhibiting the activation of HSCs and affecting the occurrence and development of liver fibrosis. ,,,,.
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Mitochondria are dynamic organelles that continuously divide and fuse. In recent years, in addition to the studies related to mitochondrial metabolism, the unique dynamics of mitochondria have gradually attracted researchers' attention. A growing body of research has revealed that mitochondrial dynamics are related to the biological behavior of tumor cells. Mitochondrial fission proteins (mitochondrial fission protein 1, FIS1) mediate the assembly of mitochondrial fission complexes and participate in the execution of mitochondrial fission. They are important proteins in the process of mitochondrial fusion and fission. However, few studies have revealed the expression and role of FIS1 in human cervical cancer. In this study, the expression level of FIS1 in human cervical cancer tissues and paracancer tissues were compared. The results showed that the level of FIS1 mRNA in human cervical cancer tissues was significantly lower than that in paracancer tissues (P<0. 01). Further KEGG pathway and GO Term-BP pathway analysis showed that the differential genes are mainly related to mitochondrial biological functions. Subsequently, HeLa cells with overexpressed FIS1 were investigated for their proliferation, migration, mitochondrial fission and ROS levels. The experimental results showed that FIS1 overexpression decreased HeLa cell proliferation and migration ability, enhanced mitochondrial fission and higher ROS levels. In conclusion, the expression of FIS1 in human cervical cancer cells was attenuated, while overexpression of FIS1 resulted in a series of abnormal biological functions in human cervical cancer cells. Further studies can be carried out to investigate the role of FIS1 in the treatment of human cervical cancer.