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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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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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OBJECTIVE@#To review the research progress of mitochondrial dynamics mediated by optic atrophy 1 (OPA1) in skeletal system diseases.@*METHODS@#The literatures about OPA1-mediated mitochondrial dynamics in recent years were reviewed, and the bioactive ingredients and drugs for the treatment of skeletal system diseases were summarized, which provided a new idea for the treatment of osteoarthritis.@*RESULTS@#OPA1 is a key factor involved in mitochondrial dynamics and energetics and in maintaining the stability of the mitochondrial genome. Accumulating evidence indicates that OPA1-mediated mitochondrial dynamics plays an important role in the regulation of skeletal system diseases such as osteoarthritis, osteoporosis, and osteosarcoma.@*CONCLUSION@#OPA1-mediated mitochondrial dynamics provides an important theoretical basis for the prevention and treatment of skeletal system diseases.
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Humans , GTP Phosphohydrolases/genetics , Mitochondrial Dynamics , Osteoarthritis , OsteoporosisABSTRACT
OBJECTIVE@#To summarize the role of chondrocyte mitochondrial homeostasis imbalance in the pathogenesis of osteoarthritis (OA) and analyze its application prospects.@*METHODS@#The recent literature at home and abroad was reviewed to summarize the mechanism of mitochondrial homeostasis imbalance, the relationship between mitochondrial homeostasis imbalance and the pathogenesis of OA, and the application prospect in the treatment of OA.@*RESULTS@#Recent studies have shown that mitochondrial homeostasis imbalance, which is caused by abnormal mitochondrial biogenesis, the imbalance of mitochondrial redox, the imbalance of mitochondrial dynamics, and damaged mitochondrial autophagy of chondrocytes, plays an important role in the pathogenesis of OA. Abnormal mitochondrial biogenesis can accelerate the catabolic reaction of OA chondrocytes and aggravate cartilage damage. The imbalance of mitochondrial redox can lead to the accumulation of reactive oxygen species (ROS), inhibit the synthesis of extracellular matrix, induce ferroptosis and eventually leads to cartilage degradation. The imbalance of mitochondrial dynamics can lead to mitochondrial DNA mutation, decreased adenosine triphosphate production, ROS accumulation, and accelerated apoptosis of chondrocytes. When mitochondrial autophagy is damaged, dysfunctional mitochondria cannot be cleared in time, leading to ROS accumulation, which leads to chondrocyte apoptosis. It has been found that substances such as puerarin, safflower yellow, and astaxanthin can inhibit the development of OA by regulating mitochondrial homeostasis, which proves the potential to be used in the treatment of OA.@*CONCLUSION@#The mitochondrial homeostasis imbalance in chondrocytes is one of the most important pathogeneses of OA, and further exploration of the mechanisms of mitochondrial homeostasis imbalance is of great significance for the prevention and treatment of OA.
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Humans , Reactive Oxygen Species/metabolism , Chondrocytes/metabolism , Osteoarthritis/metabolism , Homeostasis , Mitochondria/metabolism , Cartilage, Articular/metabolismABSTRACT
According to the traditional Chinese medicine(TCM) theory, Qi is the essential component maintaining life. Mitochondria are the cellular organelles that generate energy. Qi exhibits abundant common characteristics in bioenergetics compared with mitochondria which control the cellular energy through fusion and fission. Studies have proven that the qi-tonifying function of Chinese medicinal plants and their components facilitates mitochondrial fusion, therefore enhancing ATP synthesis. These studies provide a framework for deciphering the pharmacological mechanisms of Qi-tonifying herbs. This article introduces the common source and function shared by Qi and mitochondria and the regulatory effects of herbal remedies on energy from mitochondria dynamics. This review aims to interpret the connotation of tonifying qi in TCM theory based on the modern biomedical theory.
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Medicine, Chinese Traditional , Drugs, Chinese Herbal/pharmacology , Qi , Mitochondrial Dynamics , Plants, MedicinalABSTRACT
AIM: To investigate the effects of modified Zhujing Pill on the mitochondrion structure and dynamin-related protein of retinal pigment epithelial cells(RPEs)in mice with form deprivation myopia.METHODS: 3-week-old C57BL/6J mice were randomly divided into control group, model group and Chinese medicine group, with 10 mice in each group. Myopia model of the right eye of mice was established by means of form deprivation in model and Chinese medicine groups. After 4wk, the Chinese medicine group were given intragastric administration of modified Zhujing Pill suspension 0.546g/(kg·d)(0.2mL/d)for 4wk, and same amount of saline was given to mice in other groups at the same time of modeling. The axial length and diopter of the right eye of the mouse were measured before and after the experiment by A-ultrasound and a strip retinoscope respectively. At the end of the experiment, the mitochondrial ultrastructure of RPEs was observed by transmission electron microscope. Western blot, and real-time fluorescent quantitative PCR(q-PCR)were used to detect quantitative and gene expression of mitofusin 1(MFN1), optic atrophy 1(OPA1), and dynamin-related protein 1(DRP1)in retinal tissues respectively.RESULTS: At the beginning of the experiment, there was no statistically significant difference in axial length and diopter of the right eye of the mouse in control, model and Chinese medicine groups(P>0.05). At the end of the experiment, compared with the control group, the mice in the model group and the Chinese medicine group had lower diopter and continuously prolonged axial length(all P<0.05), while the mice in the Chinese medicine group had significantly shorter axial length and higher diopter than the model group(all P<0.05). Western blot and q-PCR results showed that the relative expression of MFN1 and OPA1 decreased and DRP1 increased in both the model group and the Chinese medicine group compared with the control group(all P<0.05), and the relative expression of MFN1 and OPA1 increased in the Chinese medicine group compared with the model group(all P<0.05). The electron microscopic results showed that the mitochondria in the right retina of the mice were only mildly swollen in the Chinese medicine group, while the mitochondria in the model group were obviously swollen and disordered and empty.CONCLUSION: Modified Zhujing Pill could protect the retinal mitochondria by regulating the key proteins of mitochondrial dynamics(MFN1, OPA1, and DRP1), and it has a protective effect on the retina of axial myopic mice.
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Isoliquiritigenin (ISL) is a flavonoid compound isolated from licorice. It possesses excellent antioxidant and anti-diabetic activities. This study aims to investigate the molecular mechanism underlying the alleviatory effect of ISL on energy metabolism imbalance caused by type 2 diabetes mellitus (T2DM). 8-week-old male C57BL/6J mice were used in in vivo experiments. The high-fat-high-glucose diet combined with intraperitoneal injection of streptozotocin was applied to establish T2DM animal model. All animal experiments were performed in accordance with the Institutional Guidelines of Laboratory Animal Administration issued by the Committee of Ethics at Beijing University of Chinese Medicine. HepG2 cells were used in in vitro experiments. Enzyme-linked immunosorbent assay (ELISA) and real-time quantitative polymerase chain reaction (RT-qPCR) were used to examine the protein and mRNA levels of mitochondrial function-related targets. The levels of reactive oxygen species (ROS) and mitochondrial membrane potential (MMP) in HepG2 cells were measured by the flow cytometry. Additionally, the molecular docking of ISL and key target proteins was analyzed. It was found that ISL significantly inhibited the activity of mitochondrial respiratory chain complex I and increased the protein levels of uncoupling protein 2 (UCP2) in the livers of mice and HepG2 cells. It also obviously decreased the ROS levels and increased the MMP levels in cultured HepG2 cells. In addition, ISL promoted mitochondrial biogenesis by activating proliferator-activated receptor gamma co-activator 1α (PGC-1α) and enhanced mitophagy by upregulating Parkin. It also improved mitochondrial fusion by increasing the mRNA and protein levels of mitofusin 2 (MFN2). In conclusion, ISL alleviates energy metabolism imbalance caused by T2DM through suppression of excessive mitochondrial oxidative phosphorylation and promotion of mitochondrial biogenesis, mitophagy, and fusion.
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The aim of this study was to investigate the role and mechanism of terpinen-4-ol (T4O) on high glucose (HG) -induced calcification in vascular smooth muscle cell (VSMC). To investigate the role of T4O on HG-induced calcium deposition, osteogenic phenotypic transformation and mitochondrial dynamics in VSMC, Mdivi-1, a mitochondrial dynamin-related protein 1 (Drp-1) inhibitor, was used to analyze the correlation between mitochondrial dynamics and VSMC calcification and the role of T4O. Alizarin red S staining was used to observe calcium salt deposition and flow cytometry to detect intracellular Ca2+ content; Western blot and immunofluorescence were used to detect the expression of phenotypic switching-related markers α-smooth muscle actin (α-SMA), bone morphogenetic protein 2 (BMP2) and Runt related transcription factor 2 (Runx2), and mitochondrial dynamics-related markers mitofusin 1 (MFN1), mitofusin 2 (MFN2) and Drp-1. The results showed that low and high doses of T4O could inhibit HG-induced down-regulation of α-SMA, MFN1 and MFN2 expression levels, and up-regulation of BMP2, Runx2 and Drp-1 expression levels, reduce intracellular Ca2+ content and calcium salt deposition, and effectively inhibit HG-induced VSMC calcification and mitochondrial dynamics disorders. The T4O group, Mdivi-1 group and T4O+Mdivi-1 group were able to up-regulate the expression levels of HG-induced α-SMA, MFN1 and MFN2, down-regulate the protein expression levels of BMP2, Runx2 and Drp-1, and inhibit calcium salt deposition, and there was no significant difference between the above indexes in the T4O and T4O+Mdivi-1 groups. The above findings suggest that T4O can inhibit the expression level of Drp-1, regulate the disturbance of mitochondrial dynamics, and suppress HG-induced VSMC calcification.
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Objective:To evaluate the relationship between mitochondrial calcium uniporter protein (MCU)-mediated mitochondrial dynamics and intestinal ischemia-reperfusion (I/R) injury in mice.Methods:Twenty-four wild-type adult male C57BL/6J mice, aged 6-8 weeks, weighing 18-20 g, were divided into 4 groups ( n=6 each) using a random number table method: sham operation group (S group), intestinal I/R group (IIR group), sham operation+ MCU inhibitor Ru360 group (S+ Ru360 group) and intestinal I/R + Ru360 group (IIR+ Ru360 group). The mouse model of intestinal I/R injury was prepared by clamping the root of the superior mesenteric artery for 45 min followed by 2 h of reperfusion in anesthetized animals. Small intestinal tissues were obtained at the end of reperfusion for examination of the intestinal mucosal injury which was scored according to Chiu and for determination of the content of malondialdehyde (MDA) (TBA method), activity of superoxide dismutase (SOD) (WST-8 method), content of lactic dehydrogenase (LDH) (colorimetric method), and expression of MCU, dynamin-related protein 1 (Drp1), recombinant human mitochondrial fission 1 protein (Fis1), mitofusin-1 (Mfn1) and Mfn2 (by Western blot). Results:Compared with S and S+ Ru360 groups, the Chiu′s score and contents of MDA and LDH were significantly increased, the activity of SOD was decreased, the expression of MCU, Drp1 and Fis1 was up-regulated, and the expression of Mfn1 and Mfn2 was down-regulated in IIR and IIR+ Ru360 groups ( P<0.05). Compared with IIR group, the Chiu′s score and contents of MDA and LDH were significantly decreased, the activity of SOD was increased, the expression of MCU, Drp1 and Fis1 was down-regulated, and the expression of Mfn1 and Mfn2 was up-regulated in IIR+ Ru360 group ( P<0.05). Conclusions:The mechanism underlying intestinal I/R injury may be related to MCU-induced promotion of mitochondrial fission, reduction of mitochondrial fusion and mediation of imbalance in mitochondrial dynamics in mice.
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Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease affecting both upper and lower motor neurons (MNs) with large unmet medical needs. Multiple pathological mechanisms are considered to contribute to the progression of ALS, including neuronal oxidative stress and mitochondrial dysfunction. Honokiol (HNK) has been reported to exert therapeutic effects in several neurologic disease models including ischemia stroke, Alzheimer's disease and Parkinson's disease. Here we found that honokiol also exhibited protective effects in ALS disease models both in vitro and in vivo. Honokiol improved the viability of NSC-34 motor neuron-like cells that expressed the mutant G93A SOD1 proteins (SOD1-G93A cells for short). Mechanistical studies revealed that honokiol alleviated cellular oxidative stress by enhancing glutathione (GSH) synthesis and activating the nuclear factor erythroid 2-related factor 2 (NRF2)-antioxidant response element (ARE) pathway. Also, honokiol improved both mitochondrial function and morphology via fine-tuning mitochondrial dynamics in SOD1-G93A cells. Importantly, honokiol extended the lifespan of the SOD1-G93A transgenic mice and improved the motor function. The improvement of antioxidant capacity and mitochondrial function was further confirmed in the spinal cord and gastrocnemius muscle in mice. Overall, honokiol showed promising preclinical potential as a multiple target drug for ALS treatment.
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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.
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Naringin (Nar) has been reported to exert potential hepatoprotective effects against acetaminophen (APAP)-induced injury. Mitochondrial dysfunction plays an important role in APAP-induced liver injury. However, the protective mechanism of Nar against mitochondrial damage has not been elucidated. Therefore, the aim of this study was to investigate the hepatoprotective effects of Nar against APAP and the possible mechanisms of actions. Primary rat hepatocytes and HepG2 cells were utilized to establish an in vitro model of APAP-induced hepatotoxicity. The effect of APAP and Nar on cell viability was evaluated by a CCK8 assay and detection of the concentrations of alanine aminotransferase, aspartate aminotransferase, and lactate dehydrogenase. The cellular concentrations of biomarkers of oxidative stress were measured by ELISA. The mRNA expression levels of APAP-related phase II enzymes were determined by real-time PCR. The protein levels of Nrf2, phospho (p)-AMPK/AMPK, and biomarkers of mitochondrial dynamics were determined by western blot analysis. The mitochondrial membrane potential (MMP) was measured by high-content analysis and confocal microscopy. JC-1 staining was performed to evaluate mitochondrial depolarization. Nar pretreatment notably prevented the marked APAP-induced hepatocyte injury, increases in oxidative stress marker expression, reductions in the expression of phase II enzymes, significant loss of MMP, mitochondrial depolarization, and mitochondrial fission in vitro. In conclusion, Nar alleviated APAP-induced hepatocyte and mitochondrial injury by activating the AMPK/Nrf2 pathway to reduce oxidative stress in vitro. Applying Nar for the treatment of APAP-induced liver injury might be promising.
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Mitochondrial dynamics regulates mitochondrial morphology and functions.Imbalance in mitochondrial dynamics with aging leads to mitochondrial dysfunction, accelerates the aging process and is closely related to the occurrence and progression of age-related diseases.However, the specifics of the relationship between aging and altered mitochondrial dynamics are still not fully understood.Here, we review the link between mitochondrial dynamics and aging, and discuss mechanisms underlying age-related diseases associated with altered mitochondrial dynamics, aiming to identify novel therapeutic targets and strategies for the management of age-related diseases.
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This study aims to explore the effect of icariin(ICA) on mitochondrial dynamics in a rat model of chronic renal failure(CRF) and to investigate the molecular mechanism of ICA against renal interstitial fibrosis(RIF). CRF was induced in male Sprague-Dawley(SD) rats with 5/6(ablation and infarction, A/I) surgery(right kidney ablation and 2/3 infarction of the left kidney). Four weeks after surgery, the model rats were randomized into the following groups: 5/6(A/I) group, 5/6(A/I)+low-dose ICA group, and 5/6(A/I)+high-dose ICA group. Another 12 rats that received sham operation were randomly classified into 2 groups: sham group and sham+ICAH group. Eight weeks after treatment, the expression of collagen-Ⅰ(Col-Ⅰ), collagen-Ⅲ(Col-Ⅲ), mitochondrial dynamics-related proteins(p-Drp1 S616, p-Drp1 S637, Mfn1, Mfn2), and mitochondrial function-related proteins(TFAM, ATP6) in the remnant kidney tissues was detected by Western blot. The expression of α-smooth muscle actin(α-SMA) was examined by immunohistochemical(IHC) staining. The NRK-52 E cells, a rat proximal renal tubular epithelial cell line, were cultured in vitro and treated with ICA of different concentration. Cell viability was detected by CCK-8 assay. In NRK-52 E cells stimulated with 20 ng·mL~(-1) TGF-β1 for 24 h, the effect of ICA on fibronectin(Fn), connective tissue growth factor(CTGF), p-Drp1 S616, p-Drp1 S637, Mfn1, Mfn2, TFAM, and ATP6 was detected by Western blot, and the ATP content and the mitochondrial morphology were determined. The 20 ng·mL~(-1) TGF-β1-stimulated NRK-52 E cells were treated with or without 5 μmol·L~(-1) ICA+10 μmol·L~(-1) mitochondrial fusion promoter M1(MFP-M1) for 24 h and the expression of fibrosis markers Fn and CTGF was detected by Western blot. Western blot result showed that the levels of Col-Ⅰ, Col-Ⅲ, and p-Drp1 S616 were increased and the levels of p-Drp1 S637, Mfn1, Mfn2, TFAM, and ATP6 were decreased in 5/6(A/I) group compared with those in the sham group. The levels of Col-Ⅰ, Col-Ⅲ, and p-Drp1 S616 were significantly lower and the levels of p-Drp1 S637, Mfn1, Mfn2, TFAM, and ATP6 were significantly higher in ICA groups than that in 5/6(A/I) group. IHC staining demonstrated that for the expression of α-SMA in the renal interstitium was higher in the 5/6(A/I) group than in the sham group and that the expression in the ICA groups was significantly lower than that in the 5/6(A/I) group. Furthermore, the improvement in the fibrosis, mitochondrial dynamics, and mitochondrial function were particularly prominent in rats receiving the high dose of ICA. The in vitro experiment revealed that ICA dose-dependently inhibited the increase of Fn, CTGF, and p-Drp1 S616, increased p-Drp1 S637, Mfn1, Mfn2, TFAM, and ATP6, elevated ATP content, and improved mitochondrial morphology of NRK-52 E cells stimulated by TGF-β1. ICA combined with MFP-M1 further down-regulated the expression of Fn and CTGF in NRK-52 E cells stimulated by TGF-β1 compared with ICA alone. In conclusion, ICA attenuated RIF of CRF by improving mitochondrial dynamics.
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Animals , Female , Humans , Male , Rats , Adenosine Triphosphate/pharmacology , Fibrosis , Flavonoids , Infarction/pathology , Kidney , Kidney Failure, Chronic , Mitochondrial Dynamics , Rats, Sprague-Dawley , Renal Insufficiency, Chronic , Transforming Growth Factor beta1/metabolismABSTRACT
Objective:To observe the expression of sirtuin 3 (Sirt3) and mitochondrial damage-associated proteins in lipopolysaccharide (LPS)-induced acute kidney injury mouse model and renal tubular epithelial cells, and to explore the role of Sirt3 in LPS-induced abnormal mitochondrial dynamics in renal tubular epithelial cells.Methods:Eighteen specific pathogen free (SPF) male C57BL/6 mice were randomly assigned to control group, LPS 24 h group and LPS 48 h group. The control group was intraperitoneally injected with physiological saline (0.1 ml/10 g), and LPS 24 h group and LPS 48 h group were intraperitoneally injected with LPS (10 mg/kg) solution. Renal functional indexes of mice were analyzed by automatic biochemical analyzer. The pathological change of the kidney was observed by HE staining, and the expressions of dynamin-related protein-1 (Drp1), optic atrophy type 1 (Opa1) and Sirt3 were evaluated by Western blotting. Expression and distribution of Sirt3 in kidney was assessed by immunohistochemistry. Human renal tubular epithelial cells (HK-2) were exposed to 10 μg/ml LPS for 24 h, and the expression of Drp1, Opa1 and Sirt3 were detected by Western blotting. Cell apoptosis was assessed by Hoechst-33342 staining. After transfection to HK-2 cells with pcDNA3.1-Sirt3 recombinant plasmid, the expressions of Sirt3, Drp1, Opa1 and cell apoptosis were detected by the same methods as above.Results:(1) The levels of blood urea nitrogen and serum creatinine in LPS group were significantly higher than those in control group (both P<0.05), and the pathological changes of kidney were obvious. (2) Compared with the control group, the expression of mitochondrial fission-associated protein Drp1 in renal tissue of LPS group was significantly higher ( P<0.05), and the expression of mitochondrial fusion associated protein Opa1 was significantly lower ( P<0.05). (3) Compared with the control group, the expression of Sirt3 in LPS group was significantly lower ( P<0.05), and immunohistochemistry results showed that Sirt3 was mainly expressed in glomerular vascular endothelial cells and renal tubular epithelial cells. (4) In vitro, LPS stimulation induced increased Drp1 expression in HK-2 cells ( P<0.05), decreased Opa1 and Sirt3 expression (both P<0.05), and increased apoptosis ( P<0.05). (5) LPS-induced mitochondrial dynamics disturbance and apoptosis were alleviated by pcDNA3.1-Sirt3 recombinant plasmid transfection. Conclusions:LPS can induce down-regulation of Sirt3 expression and disturbance of mitochondrial dynamics, and Sirt3 may play a protective role in LPS-induced acute kidney injury by regulating mitochondrial dynamics.
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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 D<sub>3</sub> （VitD<sub>3</sub>） at 300 000 U·kg<sup>-1</sup> and then at 200 000 U·kg<sup>-1</sup> 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<sup>-1</sup>） 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.
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Mitochondria are high dynamic organelles in living cells that maintain cellular metabolic processes and therefore mitochondrial quality control, which play an important role in the maintenance of intracellular homeostasis, is crucial for cell survival. It was reported that mitochondrial dynamics and mitophagy are two main mechanisms in the regulation of mitochondrial quality control. In the central nervous system, maintenance of mitochondrial function and morphology requires fission and fusion of these dynamic organelles. Mitophagy, a selective form of autophagy, which removes abnormal and dysfunctional mitochondria, plays an indispensable role in regulating mitochondrial homeostasis in neurons. Once these systems are disrupted, dysfunctional mitochondria accumulate and potentiate neuronal death, which is associated with reduced levels of ATP and excessive production of reactive oxygen species (ROS). In recent years, there has been increasing evidence suggesting that mitochondrial dynamics imbalance and mitophagy disorders are involved in the pathophysiology of neurodegenerative diseases. In this review, the most recent progress on the molecular mechanisms of mitochondrial dynamics and mitophagy was discussed their roles on the pathological process of neurodegenerative diseases was focused. Elucidation of the regulation of mitochondrial dynamics and mitophagy may become new targets for the treatment of neurodegenerative diseases.
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Objective: To investigate the inhibitory effect of mitochondrial dynamics changes on the tumor growth of transplanted melanoma in the APP/PS1 the mice and its mechanism. Methods: The male C57BL/6J (C57) and APP/PS1 mice were divided into C57 transplantation tumor group (n = 7) and APP/PS1 transplantation tumor group (n = 7). The tumor appearance time was observed and the tumor volume of the mice in two groups were calculated and the growth curves of the mice in two groups were drawn. The morphology of tumor tissue of the mice in two groups was observed under light microscope, the expression levels of mitofusion 2 (Mfn2), dynamin related protein (Drpl), fission 1 (Fis1), ubiquitin and polyubiquitin, LC3- II, PTEN induced putative kinase 1 (PINK1) and Parkin proteins in tumor tissue of the mice in two groups were detected by Western blotting method. Results: The tumor tissue under the skin of the mice in C57 transplantation tumor group and APP/PS1 transplantation tumor group was found with the melanoma granules in the tumor cells. Compared with C57 transplantation tumor group, the tumor appearance time of the mice in APP/PS1 transplantation tumor group was late, and the tumor volume was decreased (P < 0. 0 5); the expression level of Mfn2 protein in tumor tissue of the mice was decreased (P < 0. 0 5); the expression levels of Drpl and Fisl proteins were increased (P < 0. 0 5), and the expression levels of ubiquitin and polyubiqitin, LC3- II, PINK1 and Parkin proteins in tumor tissue of the mice in APP/PS1 transplantation tumor group were all increased (P < 0. 0 5). Conclusion: The growth of tumor in the APP/PS1 mice with transplanted melanoma is slow, and its mechanism may be related to PINK1/Parkin pathway involved in the mitochondrial autophagy.
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OBJECTIVE: To observe the effects of electroacupuncture (EA) at "Zusanli" (ST36) on the ultrastructure and mitochondrial dynamics of skeletal muscle tissue in spleen qi deficiency rats, so as to explore the partial action mechanism of EA at ST36 for spleen deficiency syndrome. METHODS: Twenty-four male SD rats were randomly divided into 4 groups: normal group, model group, ST36 group and non-acupoint group (n＝6 in each group). The model of spleen qi deficiency syndrome was established by improper diet and exhaustive swimming. EA (2 Hz/15 Hz, 0.5 mA) was applied to bilateral ST36 in the ST36 group and non-acupoint in the non-acupoint group for 20 min, once daily for 7 days. The colorimetric method was used to detect the ATP content in skeletal muscle tissue. The ultrastructure changes of skeletal muscle tissue were observed by transmission electron microscopy. The expression levels of optic atrophy 1 (Opa1) and dynamin-related protein 1 (Drp1) mRNA and proteins in the skeletal muscle tissue were determined by fluorescence quantitative real-time PCR and Western blot, respectively. RESULTS: The ATP content in skeletal muscle tissue of model group was significantly lower than that in the normal group (P<0.05), while significantly higher in the ST36 group than that in the model group and non-acupoint group (P<0.05). Transmission electron microscopy showed that a large number of muscle fibers that were ruptured, damaged, and disorganized; moreover, many vacuoles with different sizes, and abnormally shaped or swollen mitochondria were observed in the model group. ST36 treatment improved the disor-dered fiber arrangement, and reduced the population of damaged mitochondria; thus, fused and elongated mitochondria were readily observed. Compared with the model group, there were no obvious improvements in the non-acupoint group. Compared with the normal group, the expression levels of Opa1 and Drp1 mRNAs and proteins in the skeletal muscle tissue were significantly lower in the model group (P<0.05). After the treatment, the expression levels of Opa1 and Drp1 mRNAs and proteins were up-regulated in the ST36 group (P<0.05), and the expression of Drp1 protein was up-regulated in the non-acupoint group (P<0.05)．. CONCLUSION: EA at ST36 can correct the imbalance of mitochondrial fission and fusion in skeletal muscle of rats with spleen qi deficiency, thereby improving the damage of mitochondrial structure and function, and leading to an increase of energy metabolism.
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Objective::To observe the intervention effect of Yiqi Huoxue recipe (YQHX) on ventricular remodeling in rats with chronic heart failure, in order to explore its mechanism. Method::Among 40 male SD rats, 10 were randomly selected as the sham operation group. The left anterior descending coronary artery ligation was performed to construct the chronic heart failure(CHF) rat model. After modeling, they were randomly divided into model group, captopril group(13.5 mg·kg-1·d-1) and YQHX group (20 g·kg-1·d-1), and orally given the corresponding drugs. After 8 weeks of intervention, cardiac tissues were collected, body mass and heart mass were weighed, and echocardiography were performed to detect the changes in cardiac structure. Masson staining was performed to determine the myocardial interstitial collagen volume fraction. Western blot was used to detect the expression levels of mitochondrial fusion protein optic atrophy 1 (Opa1) and cleavage protein dynamic-related protein 1 (Drpl). The quantitative real-time fluorescence polymerase chain reaction(Real-time PCR)was applied to detect the expressions of Wnt/β-catenin pathway-related factors such as lipoprotein receptor-related protein 6 (LRP6), glycogen synthase kinase-3β (GSK-3β) and β-catenin. Result::Compared with the sham group, the left ventricular wall of the model group was significantly thickened (P<0.05), the cardiac cavity was significantly enlarged, and the content of collagen in the myocardial interstitium was increased (P<0.01). The expression level of Opal decreased, the expression level of Drp1 increased (P<0.05), the mRNA expression level of LRP6, GSK-3, and β-catenin increased (P<0.01). Compared with the model group, YQHX group can reduce ventricular wall thickening, heart chamber enlargement, myocardial interstitial collagen content, up-regulate the low expression of Opa1, but down-regulate the high expressions of Drpl, LRP6, GSK-3β, β-catenin(P<0.05, P<0.01). Conclusion::YQHX can effectively alleviate ventricular remodeling and improve mitochondrial energy metabolism in rats with CHF. The mechanism may be related to the inhibition of Wnt/β-catenin related factors.