Cloning and gene functional analysis study of dynamin-related protein GeDRP1E gene in Gastrodia elata / 药学学报

The gene GeDRP1E encoding dynamin-related protein 1E in Gastrodia elata was cloned by specific primers which were designed based on the transcriptome data of G. elata. Bioinformatics analysis on GeDRP1E gene was carried out by using ExPASy, ClustalW, MEGA, etc. Positive transgenic Arabidopsis plant and potato minituber were obtained with the genetic transformation system of Arabidopsis and potato. The plant height and seed setting rate of transgenic Arabidopsis, and agronomic characters, such as size, weight and starch content of potato minituber of transgenic potato were tested and analyzed. And GeDRP1E gene function was preliminarily investigated. The results showed that the open reading frame of GeDRP1E gene was 1 899 bp in length and 632 amino acids residues were encoded, with a relative molecular weight of 69.90 kDa and a molecular formula of C3079H4973N883O933S19. It was predicted that the theoretical isoelectric point was 7.27, the instability coefficient was 43.34, and the average hydrophilicity index was -0.259, which was indicative of an unstable hydrophilic protein. GeDRP1E has no transmembrane structure and signal peptide, and was localized in the cytoplasm. The phylogenetic tree showed that GeDRP1E was highly homologous with DRP1E proteins of other plant species, among which GeDRP1E had the highest homology with DcDRP1E (XP_020689662.1) in Dendrobium candidum, reaching 90.05%. GeDRP1E plant expression vector pCambia1300-35Spro-GeDRP1E was constructed by double digests, and Arabidopsis complementary mutant and potato overexpression strain of GeDRP1E gene were obtained by Agrobacterium-mediated gene transformation. Compared with the Arabidopsis AtDRP1E mutant, the height and seed setting rate of the GeDRP1E complementation mutant were rescued. The minituber of GeDRP1E overexpression potato had larger size, heavier weight and higher starch content, comparing to wild-type potato. It was preliminarily induced that GeDRP1E was involved in mitochondrial morphology regulation, which related to the growth and development of Arabidopsis plants and potato miniature. The research results laid a foundation for further elucidating the molecular mechanisms underlying the growth and development of G. elata tuber development.

Mechanism of action of formononetin in alleviating allergic asthma through DRP1-NLRP3 signaling pathway / 中国药理学通报

Aim To investigate the mechanism by which formononetin (FN) inhibits mitochondrial dynamic-related protein 1 (DRP1) -NLRP3 axis via intervening the generation of ROS to reduce allergic airway inflammation. Methods In order to establish allergic asthma mouse model, 50 BALB/c mice aged 8 weeks were divided into the control group, model group, FN treatment group and dexamethasone group after ovalbumin (OVA) induction. Airway inflammation and collagen deposition were detected by HampE and Masson staining. Th2 cytokines and superoxide dismutase (SOD), catalase (CAT), malondialdehyde (MDA), and IgE levels in bronchoalveolar lavage fluid (BALF) were measured by ELISA, ROS in BEAS-2B cells was assessed by DCFH-DA staining, DRP1 expression in lung tissue and BEAS-2B cells was detected by immunohistochemistry and immunofluorescence, and the DRP1-NLRP3 pathway was analyzed by immunoblotting. Results FN treatment could effectively ameliorate the symptoms of asthmatic mouse model, including reducing eosinophil accumulation, airway collagen deposition, decreasing Th2 cytokine and IgE levels, reducing ROS and MDA production, increasing SOD and CAT activities, and regulating DRP1-NLRP3 pathway-related protein expression, thereby relieving inflammation. Conclusion FN ameliorates airway inflammation in asthma by regulating DRP1-NLRP3 pathway.

Panax notoginseng saponin Rl attenuates allergic rhinitis through AMPK/DRP1 mediated mitochondrial fission / 中国药理学通报

Aim To investigate whether notoginsenoside Rl (PNS-R1) alleviates allergic rhinitis (AR) through AMP-activated protein kinase (AMPK)/mitochondrial fission critical protein (DRP1) -mediated mitochondrial fission. Methods Different doses of PNSRl were used to treat ovalbumin (OVA) -induced AR model mice,and the inhibitory effect of PNS-R1 on AR was investigated by observing allergic symptoms such as nasal rubbing and sneezing, as well as HE staining of nasal tissues. Serum IgE levels and nasal lavage fluid (NLF) inflammatory cytokine levels were detected by enzyme-linked immunosorbent assay (ELISA) and apoptosis-related proteins were detected by Western blot. In vitro human nasal epithelial cells (HNEpC) were stimulated with IL-13 to observe apoptosis, mitochondrial membrane potential, cellular ROS and mitochondrial ROS production, as well as the expression levels of AMPK/DRP1, expression levels of the TXNIP/NLRP3 inflammasomes and the translocation of DRP1. Results PNS-R1 attenuated allergic symptoms in AR mice, HE staining reduced inflammatory cells and reduced the levels of OVA-specific IgE in serum, and the levels of IL-4, IL-6, and IL-8 in NLF. PNS-R1 attenuated the apoptosis and ROS production of nasal epithelial cells in AR. In vitro PNS-R1 could up-regulate mitochondrial membrane potential after IL-13 stimulation, reduce ROS and mtROS production, the proportion of apoptotic positive cells, and reduce cleaved caspase-3, Bax, and up-regulate Bcl-2 expression, down-regulate DRP1 phosphorylation (Ser 616) and DRP1 translocation at the mitochondrial membrane in an AMPK-dependent manner, reducing TXNIP/NLRP3 expression. Conclusions PNS-R1 can protect mitochondrial integrity by inhibiting the AMPK/DRP1 signaling axis and its subsequent TXNIP/NLRP3 signaling axis,thereby alleviating rhinitis in AR mice.

JTE-013 mediates RhoA/ROCKl/Drpl signaling axis regulating mitochondrial damage and apoptosis to alleviate allergic rhinitis / 中国药理学通报

Aim To investigate the protective effect and mechanism of JTE-013 on allergic rhinitis (AR) by regulating mitochondrial injury and apoptosis through RhoA/ROCKl/Drpl pathway. Methods AR model was established by ovalbumin (OVA) in mice. Nasal tissue sections were then stained with HE, TUNEL and DHE. Western blot assay. In vitro, human nasal epithelial cells (HNEpCs) were stimulated with human recombinant interleukin-13 (IL-13), and the effects of JTE-013 and Y27632-related protein expression were detected by Western blot. Immunofluorescence was used to observe the effects of JTE-013 and Y 27632 on total ROS, mitochondrial membrane potential and mitochondrial ROS generation, Drpl translocation and Cyt-c expression in cells. Results JTE-013 reduced the frequency of nose rubbing and sneezing, reduced nasal mucosal thickening and decreased eosinophil infiltration in AR mice. TUNEL and DHE staining results suggested that JTE-013 could inhibit apoptosis and reduce ROS expression in mouse nasal epithelial cells. Western blot showed that both JTE-013 and Y 27632 could significantly reduce RhoA, ROCK1, Drpl and p-Drpl(616), inhibit the expression of apoptotic proteins Bax, cleaved-caspase-3, Cyt-c, cleavedcaspase-9 and up-regulate the expression of p-Drpl (637) and Bcl-2. Immunofluorescence showed that inhibitors of JTE-013 or ROCK1 almost blocked IL-13mediated increase in ROS and mtROS production, inhibited decrease in mitochondrial membrane potential, and blocked Cyt-c expression and Drpl translocation in nasal mucosal epithelial cells. Conclusion JTE-013 can regulate the morphology and function of mitochondria by inhibiting RhoA/ROCKl/Drpl signaling axis, thereby alleviating nasal epithelial cell inflammation in mice with allergic rhinitis.

Berberine alleviates myocardial diastolic dysfunction by modulating Drp1-mediated mitochondrial fission and Ca2+ homeostasis in a murine model of HFpEF / 医学前沿

Heart failure with preserved ejection fraction (HFpEF) displays normal or near-normal left ventricular ejection fraction, diastolic dysfunction, cardiac hypertrophy, and poor exercise capacity. Berberine, an isoquinoline alkaloid, possesses cardiovascular benefits. Adult male mice were assigned to chow or high-fat diet with L-NAME ("two-hit" model) for 15 weeks. Diastolic function was assessed using echocardiography and noninvasive Doppler technique. Myocardial morphology, mitochondrial ultrastructure, and cardiomyocyte mechanical properties were evaluated. Proteomics analysis, autophagic flux, and intracellular Ca2+ were also assessed in chow and HFpEF mice. The results show exercise intolerance and cardiac diastolic dysfunction in "two-hit"-induced HFpEF model, in which unfavorable geometric changes such as increased cell size, interstitial fibrosis, and mitochondrial swelling occurred in the myocardium. Diastolic dysfunction was indicated by the elevated E value, mitral E/A ratio, and E/e' ratio, decreased e' value and maximal velocity of re-lengthening (-dL/dt), and prolonged re-lengthening in HFpEF mice. The effects of these processes were alleviated by berberine. Moreover, berberine ameliorated autophagic flux, alleviated Drp1 mitochondrial localization, mitochondrial Ca2+ overload and fragmentation, and promoted intracellular Ca2+ reuptake into sarcoplasmic reticulum by regulating phospholamban and SERCA2a. Finally, berberine alleviated diastolic dysfunction in "two-hit" diet-induced HFpEF model possibly because of the promotion of autophagic flux, inhibition of mitochondrial fragmentation, and cytosolic Ca2+ overload.

The role of Drp1 mediated mitochondrial dynamics balance in sepsis induced cardiomyopathy / 中华急诊医学杂志

Objective:To analyze the effect of inhibiting excessive mitochondrial fission mediated by dynamic related protein 1 (Drp1) on the function of injured cells and mitochondria in the septic myocardium, and to explore the protective effect of maintaining mitochondrial dynamic balance in the pathogenesis of sepsis induced cardiomyopathy(SIC).Methods:Rat H9C2 cardiomyocytes were cultured and stimulated with lipopolysaccharide (LPS) to establish a model of SIC. Mitochondrial division inhibitor 1 (Mdivi-1) was given 30 min before LPS stimulation. They were divided into the control group, LPS stimulated group (LPS), Mdivi-1 control group (Mdivi-1), and LPS+Mdivi-1 intervention group (LPS+Mdivi-1). CCK-8 was used to detect the cell viability, and lactate dehydrogenase (LDH) was used to detect cellular damage. A MitoTracker probe was used to observe mitochondrial morphology by laser scanning confocal microscopy, JC-1 staining was used to detect mitochondrial membrane potential level, a DCFH-DA probe was used to detect total ROS level, and an AnnexinV-FITC/PI probe was used to detect the cell apoptosis ratio. The expression levels of mitochondrial fission protein Drp1 and fusion proteins Optic Atrophy 1(Opa1) and Mitofusin2 (Mfn2) were detected by real-time PCR and Western blot. One-way ANOVA was used to compare the differences between groups, and the LSD- t test was used for pairwise comparisons between groups. Results:Compared with the control group, cell viability, the average length of mitochondria and the mitochondrial membrane potential were decreased, and ROS production, the cell apoptosis rate and LDH were increased in the LPS group (all P<0.05). After Mdivi-1 intervention, compared with the LPS-stimulated group, the cell viability was increased, myocardial cell damage was reduced, the average length of mitochondria was prolonged, mitochondrial dysfunction was alleviated, and the cell apoptosis rate was inhibited in the LPS+Mdivi-1 group (all P<0.05). Conclusions:Mdivi-1 might inhibit mitochondrial fission mediated by Drp1, maintain mitochondrial dynamic balance, alleviate mitochondrial dysfunction and protect myocardial cells from LPS-induced injury.

Effects of DNMT3A regulating Drp1 on proliferation and migration of activated hepatic stellate cells / 中国药理学通报

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. ,,,,.

Effect of the regulation of mitochondrial dynamics on renal ischemia-reperfusion injury / 器官移植

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.

Mitochondrial Dynamics Mediates Myocardial Energy Metabolism in Coronary Heart Disease due to Blood Stasis / 中国实验方剂学杂志

Objective:To explore the mechanism of energy changes in the three stages of the formation of coronary heart disease due to blood stasis in rat model from the perspective of mitochondrial fusion-fission dynamic changes. Method:Thirty healthy male rats were divided into the blank control group （<italic>n</italic>=6） and model group （<italic>n</italic>=24） using SPSS 21.0 simple random sampling method. The rats in the blank control group were fed an ordinary diet， while those in the model group a high-fat diet. After seven days of adaptive feeding， the rats were treated with intragastric administration of vitamin D₃ （VitD₃） at 300 000 U·kg^-1 and then at 200 000 U·kg^-1 14 d later. The high-fat diet continued for 21 d， and six rats were randomly selected as samples for the pre-stage blood stasis syndrome group， followed by model verification and sampling. The remaining rats continued to receive the high-fat diet for 30 d， and six were randomly selected and categorized into the sub-stage blood stasis syndrome group， followed by model verification and sampling. The rest of rats were classified into the heart blood stasis syndrome group. While continuing the high-fat diet， they were also treated with multipoint subcutaneous injection of isoproterenol （ISO，5 mg·kg^-1） for three consecutive days. One week later， the electrocardiogram （ECG） was recorded for determining whether the modeling was successful and the samples were taken at the same time. The changes in mitochondrial morphology and quantity were observed under a transmission electron microscope. The expression of mitochondrial dynamics-related proteins was measured by Western blot and the cellular localization of related proteins by immunofluorescence assay. Result:The levels of total cholesterol and low-density lipoprotein cholesterol in the pre-stage and sub-stage blood stasis syndrome groups were significantly increased as compared with those in the blank control group （<italic>P</italic><0.05）. The blood rheology index in the pre-stage blood stasis syndrome group was significantly elevated in contrast to that in the blank control group （<italic>P</italic><0.05）. The three-layered membrane of the aorta in the blank group was intact. However， the tunica media of the pre-stage blood stasis syndrome group began to show obvious calcification， with a small number of inflammatory cells adhering to the intima. The subintima and media smooth muscles in the sub-stage blood stasis syndrome group exhibited cavity structures. The three-layered structure of the arterial wall in the heart blood stasis syndrome group was severely damaged. The ECG of the blank control group revealed the regular appearance of P wave，regular QRS waveform （no broadening or deformity）， and no obvious ST-segment depression or elevation. The ECG of the pre-stage blood stasis syndrome group showed no obvious abnormalities as compared with that of the blank control group. In the sub-stage blood stasis syndrome group， the ECG showed an upward trend of the J point and slight ST-segment elevation， with the elevation≤0.1 mV. The ECG in the heart blood stasis syndrome group displayed significant ST-segment depression （>0.1 mV） and J point depression >0.1 mV. The mitochondria in the blank control group were normal in size and morphology， with clear and dense cristae， whereas those in the pre-stage blood stasis syndrome group were fusiform with sparse cristae. Some mitochondria in the sub-stage blood stasis syndrome group were significantly elongated， and even vacuole-like changes were present. In the heart blood stasis syndrome group， the mitochondria were ruptured. As demonstrated by comparison with the blank control group， the expression levels of mitofusin 2 （Mfn2）， dynamin-related protein 1 （Drp1）， and fission protein 1 （Fis1） in the model group were significantly up-regulated （<italic>P</italic><0.05，<italic>P</italic><0.01）. Compared with the pre-stage blood stasis syndrome group， the heart blood stasis syndrome group exhibited down-regulated Mfn2 （<italic>P<</italic>0.05）. Compared with the blank control group and the pre-stage blood stasis syndrome group， the sub-stage blood stasis syndrome group and the heart blood stasis syndrome group displayed down-regulated optic atrophy 1（OPA1） （<italic>P</italic><0.05，<italic>P</italic><0.01）. The Drp1 and Fis1 protein expression declined significantly in the sub-stage blood stasis syndrome group in comparison with that in the pre-stage blood stasis syndrome group （<italic>P</italic><0.05，<italic>P</italic><0.01）. The expression levels of Mfn2 and Drp1 in the heart blood stasis syndrome group were lower than those in the sub-stage blood stasis syndrome group （<italic>P<</italic>0.01）. The comparison with the blank control group showed that Mfn2 and OPA1 were extensively accumulated in mitochondria of both the pre-stage and sub-stage blood stasis syndrome groups， while the red-stained Mfn2 was significantly reduced in the heart blood stasis syndrome group. The Drp1/Fis1 fluorescence was weak in the blank group and the pre-stage blood stasis syndrome group but strong in the sub-stage blood stasis syndrome group and heart blood stasis syndrome group. Conclusion:The cardiomyocyte mitochondria dynamics changes with the change in energy demand of cardiomyocytes. Mfn2 is dominated by fusion effect in the early stage of the formation of coronary heart disease due to blood stasis. With the gradual development of this disease， Mfn2 begins to mediate mitochondrial autophagy. OPA1 plays a role in intimal fusion and cristae integrity. The decreased OPA1 expression is closely related to the accelerated progression of coronary heart disease differentiated into blood stasis syndrome. The process by which Drp1 and Fis1 separate damaged mitochondria to prepare for mitochondrial autophagy contributes to alleviating the imbalance between the energy demand and supply of human body.

Acrolein Aggravates Secondary Brain Injury After Intracerebral Hemorrhage Through Drp1-Mediated Mitochondrial Oxidative Damage in Mice / 神经科学通报·英文版

Clinical advances in the treatment of intracranial hemorrhage (ICH) are restricted by the incomplete understanding of the molecular mechanisms contributing to secondary brain injury. Acrolein is a highly active unsaturated aldehyde which has been implicated in many nervous system diseases. Our results indicated a significant increase in the level of acrolein after ICH in mouse brain. In primary neurons, acrolein induced an increase in mitochondrial fragmentation, loss of mitochondrial membrane potential, generation of reactive oxidative species, and release of mitochondrial cytochrome c. Mechanistically, acrolein facilitated the translocation of dynamin-related protein1 (Drp1) from the cytoplasm onto the mitochondrial membrane and led to excessive mitochondrial fission. Further studies found that treatment with hydralazine (an acrolein scavenger) significantly reversed Drp1 translocation and the morphological damage of mitochondria after ICH. In parallel, the neural apoptosis, brain edema, and neurological functional deficits induced by ICH were also remarkably alleviated. In conclusion, our results identify acrolein as an important contributor to the secondary brain injury following ICH. Meanwhile, we uncovered a novel mechanism by which Drp1-mediated mitochondrial oxidative damage is involved in acrolein-induced brain injury.

Acrolein Aggravates Secondary Brain Injury After Intracerebral Hemorrhage Through Drp1-Mediated Mitochondrial Oxidative Damage in Mice / 神经科学通报·英文版

Clinical advances in the treatment of intracranial hemorrhage (ICH) are restricted by the incomplete understanding of the molecular mechanisms contributing to secondary brain injury. Acrolein is a highly active unsaturated aldehyde which has been implicated in many nervous system diseases. Our results indicated a significant increase in the level of acrolein after ICH in mouse brain. In primary neurons, acrolein induced an increase in mitochondrial fragmentation, loss of mitochondrial membrane potential, generation of reactive oxidative species, and release of mitochondrial cytochrome c. Mechanistically, acrolein facilitated the translocation of dynamin-related protein1 (Drp1) from the cytoplasm onto the mitochondrial membrane and led to excessive mitochondrial fission. Further studies found that treatment with hydralazine (an acrolein scavenger) significantly reversed Drp1 translocation and the morphological damage of mitochondria after ICH. In parallel, the neural apoptosis, brain edema, and neurological functional deficits induced by ICH were also remarkably alleviated. In conclusion, our results identify acrolein as an important contributor to the secondary brain injury following ICH. Meanwhile, we uncovered a novel mechanism by which Drp1-mediated mitochondrial oxidative damage is involved in acrolein-induced brain injury.

LRRK2 Kinase Activity Induces Mitochondrial Fission in Microglia via Drp1 and Modulates Neuroinflammation

Leucine-rich repeat kinase 2 (LRRK2) mutations are the most common genetic cause of Parkinson's disease (PD). LRRK2 contains a functional kinase domain and G2019S, the most prevalent LRRK2 pathogenic mutation, increases its kinase activity. LRRK2 regulates mitochondria morphology and autophagy in neurons. LPS treatment increases LRRK2 protein level and mitochondrial fission in microglia, and down-regulation of LRRK2 expression or inhibition of its kinase activity attenuates microglia activation. Here, we evaluated the direct role of LRRK2 G2019S in mitochondrial dynamics in microglia. Initial observation of microglia in G2019S transgenic mice revealed a decrease in mitochondrial area and shortage of microglial processes compared with their littermates. Next, we elucidated the molecular mechanisms of these phenotypes. Treatment of BV2 cells and primary microglia with LPS enhanced mitochondrial fission and increased Drp1, a mitochondrial fission marker, as previously reported. Importantly, both phenotypes were rescued by treatment with GSK2578215A, a LRRK2 kinase inhibitor. Finally, the protein levels of CD68, an active microglia marker, Drp1 and TNF-α were significantly higher in brain lysates of G2019S transgenic mice compared with the levels in their littermates. Taken together, our data suggest that LRRK2 could promote microglial mitochondrial alteration via Drp1 in a kinase-dependent manner, resulting in stimulation of pro-inflammatory responses. This mechanism in microglia might be a potential target to develop PD therapy since neuroinflammation by active microglia is a major symptom of PD.

Effect of extraction of saffron crocus on mitochondrial dynamics in ischemia/reperfusion rats / 中国药理学通报

Aim To investigate the protection mecha-nism of the extraction of the saffron crocus in ischemia/reperfusion rats. Methods Hematoxylin-eosin stai-ning, electron microscopy, and neurological assess-ments were performed in a transient middle cerebral ar-tery occlusion ( tMCAO ) rat model. The role of dy-namin-related protein 1 ( Drp1 ) and optic atrophy 1 ( Opa1 ) , the two key regulators of mitochondrial fis-sion and fusion in ischemic brain damage in vivo were observed. Results In ischemia/reperfusion rats, the extraction of the saffron crocus increased the level of protein Opa1 and decreased the level of protein Drp1 . Conclusions Inhibition of Drp1 and promotion of Opa1 , which means to maintain balancing mitochondri-al dynamics, is proposed as an efficient strategy for neuroprotection against ischemic brain damage.

Hypoxia-dependent mitochondrial fission regulates endothelial progenitor cell migration, invasion, and tube formation

Tumor undergo uncontrolled, excessive proliferation leads to hypoxic microenvironment. To fulfill their demand for nutrient, and oxygen, tumor angiogenesis is required. Endothelial progenitor cells (EPCs) have been known to the main source of angiogenesis because of their potential to differentiation into endothelial cells. Therefore, understanding the mechanism of EPC-mediated angiogenesis in hypoxia is critical for development of cancer therapy. Recently, mitochondrial dynamics has emerged as a critical mechanism for cellular function and differentiation under hypoxic conditions. However, the role of mitochondrial dynamics in hypoxia-induced angiogenesis remains to be elucidated. In this study, we demonstrated that hypoxia-induced mitochondrial fission accelerates EPCs bioactivities. We first investigated the effect of hypoxia on EPC-mediated angiogenesis. Cell migration, invasion, and tube formation was significantly increased under hypoxic conditions; expression of EPC surface markers was unchanged. And mitochondrial fission was induced by hypoxia time-dependent manner. We found that hypoxia-induced mitochondrial fission was triggered by dynamin-related protein Drp1, specifically, phosphorylated DRP1 at Ser637, a suppression marker for mitochondrial fission, was impaired in hypoxia time-dependent manner. To confirm the role of DRP1 in EPC-mediated angiogenesis, we analyzed cell bioactivities using Mdivi-1, a selective DRP1 inhibitor, and DRP1 siRNA. DRP1 silencing or Mdivi-1 treatment dramatically reduced cell migration, invasion, and tube formation in EPCs, but the expression of EPC surface markers was unchanged. In conclusion, we uncovered a novel role of mitochondrial fission in hypoxia-induced angiogenesis. Therefore, we suggest that specific modulation of DRP1-mediated mitochondrial dynamics may be a potential therapeutic strategy in EPC-mediated tumor angiogenesis.

Effect of butylphthalide combine edaravone on the dynamic change of Drp1 and Mfn2 in rats with focal cerebral ischemia and its protection mechanism / 医学研究生学报

Objective Apoptosis was induced by oxidative stress in nerve cells after cerebral ischemia. It further breaks the dy-namic balance of mitochondrial division of fusion. This study aimed to investigate the effect of butylphthalide combined with edaravone treat-ment on the dynamic change of Drp1 and Mfn2 in rats with focal cere-bral ischemia cells and its protection mechanism. Methods 96 rats were divided into 4 groups according to random number table. The 4 groups were ischemia group,butylphthalide group,edaravone group and butylphthalide combined with edaravone groups(combine group),each group divided into three subgroups(3 d,7 d,14 d). Longa-Zea suppository method is adopted to establish the middle cerebral artery occlusion(MCAO)model.Butylphthalide group,edar-avone group and combine group were injected butylphthalide(0.4 g/kg)and/or edaravone(10 mL/kg)peritoneally 2 hours before surgery and 1 day after surgery. The same volume of isotonic saline was given at the same time of the other 3 groups in ischemia group. The cerebral cortex of the left ischemic region was obtained at the day 3,7,14. The evaluation of the curative effect was evaluated with neurological function score.HE staining was used to observe the cerebral cortex neuron morphological structure,protein and mRNA lev-el of Drp1 and Mfn2 was measured by western blot and RT-PCR. Results At the day 3,7,and 14,the neurological function score was higher in ischemia group than the other 3 groups(P<0.05). Compared with the combine group at day 3,7,and 14[(1.06± 0.18),(0.82±0.13),(0.57±0.10)],the neurological function score was elevated in butylphthalide group[(2.02±0.18),(1.23± 0.13),(0.86±0.10)]and edaravone group[(2.08±0.17),(1.23±0.13),(0.85±0.12)](P<0.05). At the same time point,com-pared with the ischemia group,Drp1 protein and mRNA levels were lower in the other 3 groups(P < 0.05)while Mfn2 protein and mRNA levels were elevated(P<0.05). Compared with the butylphthalide group and edaravone group,Drp1 protein and mRNA levels were lower in combine group(P<0.05)while Mfn2 protein and mRNA levels were elevated(P<0.05). Conclusion The protective effect of edaravone combined with butylphthalide is better than single use. Its mechanism may be related to the removing of oxygen free radicals and reducing oxidative stress by edaravone,and the protection of the mitochondria by butylphthalide.

Effects of carbon monoxide on lipopolysaccharide induced damage in rat alveolar macrophages / 天津医药

Objective To evaluate effects of carbon monoxide (CO) on lipopolysaccharide (LPS) induced damage and possible mechanism in rat alveolar macrophages. Methods Rat alveolar macrophages were cultured in DMEM containing 10%fetal bovine serum with 5%CO2 at 37℃in Heraeus sepatech. The cells were divided into four groups using random number table (n=10): control group (group C),CO group, LPS group and LPS+CO group. The CO release molecule-2 (CORM-2) 100 μmol/L was added into CO group,LPS 10 mg/L was added into LPS group, cells were pretreated with CORM-2 100μmol/L for 1 h then LPS 10 mg/L was added into LPS+CO group, the same amount of PBS was added to group C. Proliferation was measured by MTT assay. Apoptosis and mitochondrial membrane potential were detected with flow cytometer. The content of ATP was tested by ATP content kit. Drp1 mRNA was measured by RT-PCR, and Drp1 expression was determined by Western blot assay. Results Compared with group C, the cell vitality, content of ATP and mitochondrial membrane potential were decreased in LPS group and LPS+CO group,and cell apoptosis rate, Drp1 mRNA and protein expression were increased (P<0.05). There were no significant changes were found in CO group. Compared with LPS group, the cell vitality, content of ATP and mitochondrial membrane potential were increased in LPS+CO group,and the cell apoptosis rate, Drp1 mRNA and protein expression were decreased (P<0.05). Conclusion Carbon monoxide can alleviate LPS-induced damage in rat alveolar macrophages, which is related with down-regulation of Drp1 and amelioration of mitochondrial function.

Effects of mitochondrial fission in proliferation, apoptosis and invasion of thyroid squamous carcinoma cell line SW579 / 天津医药

Objective To detect the expression of mitochondrial dynamics proteins (Mfn2 and Drp1) in thyroid squa?mous carcinoma cell line SW579 and the effects of Mitochondrial division inhibitor, Mdivi-1, on proliferation, apoptosis and invasion of SW579. Methods In SW579 and Nthy-ori 3-1 cell lines, the expression levels of Mfn2 and Drp1 were deter?mined by western blot while the transcription level of Mfn2 and Drp1 mRNA were measured by RT-PCR. Then, SW579 cells were divided into control group (DMSO, 0.1%) and Mdivi-1 low, medium and high dose groups (Mdivi-1 of 15,30 and 45μmol/L were incubated with cells for 16 hours respectively). Then the ability of cell proliferation was detected using MTT assay, the mitochondrial membrane potential was determined by fluorescence spectrophotometer, the expression levels of cy?tochrome C and Caspase-3 were quantified by Western blot and the transcription level of the Cyt C and Caspase-3 mRNA were determined by RT-PCR. The ability of invasion in each group was measured with Transwell assays. Results Com?pared with Nthy-ori 3-1, the mRNA transcription and protein expression levels of the Mfn2 was remarkably decreased, while the mRNA transcription and protein expression of the Drp1 was significantly increased in SW579 cells (P<0.01). Compared with control group, the cell survival rates and mitochondrial membrane potential of SW579 were decreased dramat?ically (P<0.01). The mRNA transcription and protein expression of the cytochrome C and Caspase-3 were increased dra?matically (P<0.01) and the capability of invasion was markedly decreased in all the Mdivi-1 groups in a dosage dependent manner compared with those in control groups (P<0.01). Conclusion Abnormal mitochondrial dynamics may be involved in thyroid squamous cell carcinoma SW579 cells;Mdivi-1 can inhibit the cell proliferation and invasion as well as induce apoptosis.

CDK5-dependent inhibitory phosphorylation of Drp1 during neuronal maturation

Mitochondrial functions are essential for the survival and function of neurons. Recently, it has been demonstrated that mitochondrial functions are highly associated with mitochondrial morphology, which is dynamically changed by the balance between fusion and fission. Mitochondrial morphology is primarily controlled by the activation of dynamin-related proteins including dynamin-related protein 1 (Drp1), which promotes mitochondrial fission. Drp1 activity is regulated by several post-translational modifications, thereby modifying mitochondrial morphology. Here, we found that phosphorylation of Drp1 at serine 616 (S616) is mediated by cyclin-dependent kinase 5 (CDK5) in post-mitotic rat neurons. Perturbation of CDK5 activity modified the level of Drp1S616 phosphorylation and mitochondrial morphology in neurons. In addition, phosphorylated Drp1S616 preferentially localized as a cytosolic monomer compared with total Drp1. Furthermore, roscovitine, a chemical inhibitor of CDKs, increased oligomerization and mitochondrial translocation of Drp1, suggesting that CDK5-dependent phosphorylation of Drp1 serves to reduce Drp1's fission-promoting activity. Taken together, we propose that CDK5 has a significant role in the regulation of mitochondrial morphology via inhibitory phosphorylation of Drp1S616 in post-mitotic neurons.

Physiological and Pathological Significance of Dynamin-Related Protein 1 (Drp1)-Dependent Mitochondrial Fission in the Nervous System

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.