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In JoVE (1)
Other Publications (17)
- Molecular and Cellular Biology
- Journal of Bacteriology
- Journal of Bacteriology
- Free Radical Biology & Medicine
- Proceedings of the National Academy of Sciences of the United States of America
- Zhonghua Yu Fang Yi Xue Za Zhi [Chinese Journal of Preventive Medicine]
- Acta Crystallographica. Section E, Structure Reports Online
- Molecular and Cellular Biochemistry
- PloS One
- PloS One
- Atherosclerosis
- PloS One
- Drug Development and Industrial Pharmacy
- Journal of Industrial Microbiology & Biotechnology
- Bioscience Reports
- Population Health Management
- Cell Cycle (Georgetown, Tex.)
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Articles by Jie Liu in JoVE
JoVE Clinical and Translational Medicine
Contusive модели Односторонние шейки Травма спинного мозга с помощью бесконечного Ударный Horizon
1International Collaboration on Repair Discoveries (ICORD), University of British Columbia, 2Department of Orthopaedics, University of British Columbia
Надежные и повторяемые способ получения шейки одностороннего повреждения спинного мозга помощью бесконечного ударный Horizon описано. Метод использует специально разработанные рамы и зажим для стабилизации позвоночника. Стандартизированные процедуры и биомеханических параметров травмы приводят к достаточно и получили ранения.
Other articles by Jie Liu on PubMed
A Critical Role of Mitochondrial Phosphatase Ptpmt1 in Embryogenesis Reveals a Mitochondrial Metabolic Stress-induced Differentiation Checkpoint in Embryonic Stem Cells
Mitochondria are highly dynamic organelles that play multiple roles in cells. How mitochondria cooperatively modulate embryonic stem (ES) cell function during development is not fully understood. Global disruption of Ptpmt1, a mitochondrial Pten-like phosphatidylinositol phosphate (PIP) phosphatase, resulted in developmental arrest and postimplantation lethality. Ptpmt1(-/-) blastocysts failed to outgrow, and inner-cell-mass cells failed to thrive. Depletion of Ptpmt1 in conditional knockout ES cells decreased proliferation without affecting energy homeostasis or cell survival. Differentiation of Ptpmt1-depleted ES cells was essentially blocked. This was accompanied by upregulation of cyclin-dependent kinase inhibitors and a significant cell cycle delay. Reintroduction of wild-type but not of catalytically deficient Ptpmt1 C132S or truncated Ptpmt1 lacking the mitochondrial localization signal restored the differentiation capabilities of Ptpmt1 knockout ES cells. Intriguingly, Ptpmt1 is specifically important for stem cells, as ablation of Ptpmt1 in differentiated embryonic fibroblasts did not disturb cellular function. Further analyses demonstrated that oxygen consumption of Ptpmt1-depleted cells was decreased, while glycolysis was concomitantly enhanced. In addition, mitochondrial fusion/dynamics were compromised in Ptpmt1 knockout cells due to accumulation of PIPs. These studies, while establishing a crucial role for Ptpmt1 phosphatase in embryogenesis, reveal a mitochondrial metabolic stress-activated checkpoint in the control of ES cell differentiation.
Complete Genome Sequence of the Industrial Strain Ketogulonicigenium Vulgare WSH-001
Ketogulonicigenium vulgare is an industrial organism commonly used in the vitamin C industry. Here, we report the finished, annotated, and compared 3.28-Mbp high-quality genome sequence of Ketogulonicigenium vulgare WSH-001, a 2-keto-l-gulonic acid-producing industrial strain stocked in our laboratory.
Complete Genome Sequence of the Industrial Strain Bacillus Megaterium WSH-002
Bacillus megaterium, an industrial strain, has been widely used in protein production and the vitamin C industry. Here we reported a finished, annotated, and compared 4.14-Mbp high-quality genome sequence of B. megaterium WSH-002, which is the companion strain for Ketogulonicigenium vulgare in the vitamin C industry and is stocked in our laboratory.
Oxidants, Metabolism, and Stem Cell Biology
Adult stem cells persist throughout the lifetime of the organism and may therefore require specific mechanisms to limit the effects of chronic oxidative stress. Recently, several instructive genetic mouse models have demonstrated the unique susceptibility of stem cells to perturbations in metabolic or redox homeostasis. These results have implications not only for stem cell biology but also suggest a mechanistic link between intracellular oxidants and the decline in regenerative function that occurs as a normal consequence of aging.
Membrane Protein Complexes Catalyze Both 4- and 3-hydroxylation of Cinnamic Acid Derivatives in Monolignol Biosynthesis
The hydroxylation of 4- and 3-ring carbons of cinnamic acid derivatives during monolignol biosynthesis are key steps that determine the structure and properties of lignin. Individual enzymes have been thought to catalyze these reactions. In stem differentiating xylem (SDX) of Populus trichocarpa, two cinnamic acid 4-hydroxylases (PtrC4H1 and PtrC4H2) and a p-coumaroyl ester 3-hydroxylase (PtrC3H3) are the enzymes involved in these reactions. Here we present evidence that these hydroxylases interact, forming heterodimeric (PtrC4H1/C4H2, PtrC4H1/C3H3, and PtrC4H2/C3H3) and heterotrimeric (PtrC4H1/C4H2/C3H3) membrane protein complexes. Enzyme kinetics using yeast recombinant proteins demonstrated that the enzymatic efficiency (V(max)/k(m)) for any of the complexes is 70-6,500 times greater than that of the individual proteins. The highest increase in efficiency was found for the PtrC4H1/C4H2/C3H3-mediated p-coumaroyl ester 3-hydroxylation. Affinity purification-quantitative mass spectrometry, bimolecular fluorescence complementation, chemical cross-linking, and reciprocal coimmunoprecipitation provide further evidence for these multiprotein complexes. The activities of the recombinant and SDX plant proteins demonstrate two protein-complex-mediated 3-hydroxylation paths in monolignol biosynthesis in P. trichocarpa SDX; one converts p-coumaric acid to caffeic acid and the other converts p-coumaroyl shikimic acid to caffeoyl shikimic acid. Cinnamic acid 4-hydroxylation is also mediated by the same protein complexes. These results provide direct evidence for functional involvement of membrane protein complexes in monolignol biosynthesis.
[A Cost-benefit Analysis of the Influenza H1N1 Vaccination in the Primary and Junior School in Shanghai]
To evaluate the cost-benefit for the Influenza Type A H1N1 Virus (Influenze H1N1) vaccination in Shanghai primary and junior schools.
Catena-Poly[bis(dimethylazanium) [[chloridocopper(II)]-di-μ-chlorido-[chloridocopper(II)]-di-μ-azido-κN:N]]
The crystal structure of the title complex, {(C(2)H(8)N)[CuCl(2)(N(3))]}(n), exhibits inorganic chains consisting of Cu(II) cations as well azide and chloride anions. The chains, made up from Cu-Cl-Cu-N-Cu linkages, are aligned parallel to the c axis. This architecture is further stabilized by a number of N-H⋯Cl hydrogen bonds involving the protonated charge-compensating dimethyl-amine cations and chloride atoms.
An Essential Role for the Id1/PI3K/Akt/NFkB/survivin Signalling Pathway in Promoting the Proliferation of Endothelial Progenitor Cells in Vitro
The enhancement of re-endothelialisation is a critical therapeutic option for repairing injured blood vessels. Endothelial progenitor cells (EPCs) are the major source of cells that participate in endothelium repair and contribute to re-endothelialisation by reducing neointima formation after vascular injury. The over-expression of the inhibitor of differentiation or DNA binding 1 (Id1) significantly improved EPC proliferation. This study aimed to investigate the effects of Id1 on the phosphatidylinositol-3-kinase (PI3K)/Akt/nuclear factor kappa B (NFκB)/survivin signalling pathway and its significance in promoting EPC proliferation in vitro. Spleen-derived EPCs were cultured as previously described. Id1 was presented at low levels in EPCs, and was rapidly up-regulated by stimulation with vascular endothelial growth factor. We demonstrated that transient transfection of Id1 into EPCs activated the PI3K/Akt/NFκB/survivin signalling pathway and promoted EPC proliferation. The proliferation of EPCs was extensively inhibited by silencing of endogenous Id1, and knockdown of Id1 expression led to suppression of PI3K/Akt/NFκB/survivin signalling pathway in EPCs. In addition, blockade by the PI3K-specific inhibitor LY294002, Akt inhibitor, the NFκB inhibitor BAY 11-7082, the survivin inhibitor Curcumin, or the survivin inhibitor YM155 reduced the effects of Id1 transfection. These results suggest that the Id1/PI3K/Akt/NFκB/survivin signalling pathway plays a critical role in EPC proliferation. The Id1/PI3K/Akt/NFκB/survivin signalling pathway may represent a novel therapeutic target in the prevention of restenosis after vascular injury.
Sequential Alterations in Catabolic and Anabolic Gene Expression Parallel Pathological Changes During Progression of Monoiodoacetate-induced Arthritis
Chronic inflammation is one of the major causes of cartilage destruction in osteoarthritis. Here, we systematically analyzed the changes in gene expression associated with the progression of cartilage destruction in monoiodoacetate-induced arthritis (MIA) of the rat knee. Sprague Dawley female rats were given intra-articular injection of monoiodoacetate in the knee. The progression of MIA was monitored macroscopically, microscopically and by micro-computed tomography. Grade 1 damage was observed by day 5 post-monoiodoacetate injection, progressively increasing to Grade 2 by day 9, and to Grade 3-3.5 by day 21. Affymetrix GeneChip was utilized to analyze the transcriptome-wide changes in gene expression, and the expression of salient genes was confirmed by real-time-PCR. Functional networks generated by Ingenuity Pathways Analysis (IPA) from the microarray data correlated the macroscopic/histologic findings with molecular interactions of genes/gene products. Temporal changes in gene expression during the progression of MIA were categorized into five major gene clusters. IPA revealed that Grade 1 damage was associated with upregulation of acute/innate inflammatory responsive genes (Cluster I) and suppression of genes associated with musculoskeletal development and function (Cluster IV). Grade 2 damage was associated with upregulation of chronic inflammatory and immune trafficking genes (Cluster II) and downregulation of genes associated with musculoskeletal disorders (Cluster IV). The Grade 3 to 3.5 cartilage damage was associated with chronic inflammatory and immune adaptation genes (Cluster III). These findings suggest that temporal regulation of discrete gene clusters involving inflammatory mediators, receptors, and proteases may control the progression of cartilage destruction. In this process, IL-1β, TNF-α, IL-15, IL-12, chemokines, and NF-κB act as central nodes of the inflammatory networks, regulating catabolic processes. Simultaneously, upregulation of asporin, and downregulation of TGF-β complex, SOX-9, IGF and CTGF may be central to suppress matrix synthesis and chondrocytic anabolic activities, collectively contributing to the progression of cartilage destruction in MIA.
Over-expression of PDGFR-β Promotes PDGF-induced Proliferation, Migration, and Angiogenesis of EPCs Through PI3K/Akt Signaling Pathway
The proliferation, migration, and angiogenesis of endothelial progenitor cells (EPCs) play critical roles in postnatal neovascularization and re-endothelialization following vascular injury. Here we evaluated whether the over-expression of platelet-derived growth factor receptor-β (PDGFR-β) can enhance the PDGF-BB-stimulated biological functions of EPCs through the PDGFR-β/phosphoinositide 3-kinase (PI3K)/Akt signaling pathway. We first confirmed the expression of endogenous PDGFR-β and its plasma membrane localization in spleen-derived EPCs. We then demonstrated that the PDGFR-β over-expression in EPCs enhanced the PDGF-BB-induced proliferation, migration, and angiogenesis of EPCs. Using AG1295 (a PDGFR kinase inhibitor), LY294002 (a PI3K inhibitor), and sc-221226 (an Akt inhibitor), we further showed that the PI3K/Akt signaling pathway participates in the PDGF-BB-induced proliferation, migration, and angiogenesis of EPCs. In addition, the PI3K/Akt signaling pathway is required for PDGFR-β over-expression to enhance these PDGF-BB-induced phenotypes.
Hydrogen-rich Saline Prevents Neointima Formation After Carotid Balloon Injury by Suppressing ROS and the TNF-α/NF-κB Pathway
Reactive oxygen species (ROS) play a pivotal role in neointima hyperplasia after balloon injury. Molecular hydrogen has emerged as a novel antioxidant and has been proven effective in treating many diseases.
Preservation of Mouse Sperm by Convective Drying and Storing in 3-o-methyl-d-glucose
With the fast advancement in the genetics and bio-medical fields, the vast number of valuable transgenic and rare genetic mouse models need to be preserved. Preservation of mouse sperm by convective drying and subsequent storing at above freezing temperatures could dramatically reduce the cost and facilitate shipping. Mouse sperm were convectively dried under nitrogen gas in the Na-EGTA solution containing 100 mmol/L 3-O-methyl-D-glucose and stored in LiCl sorption jars (Relative Humidity, RH, 12%) at 4°C and 22°C for up to one year. The functionality of these sperm samples after storage was tested by intracytoplasmic injection into mouse oocytes. The percentages of blastocysts produced from sperm stored at 4°C for 1, 2, 3, 6, and 12 months were 62.6%, 53.4%, 39.6%, 33.3%, and 30.4%, respectively, while those stored at 22°C for 1, 2, and 3 months were 28.8%, 26.6%, and 12.2%, respectively. Transfer of 38 two- to four-cell embryos from sperm stored at 4°C for 1 year produced two live pups while 59 two- to four-cell embryos from sperm stored at 22°C for 3 months also produced two live pups. Although all the pups looked healthy at 3 weeks of age, normality of offspring produced using convectively dried sperm needs further investigation. The percentages of blastocyst from sperm stored in the higher relative humidity conditions of NaBr and MgCl(2) jars and driest condition of P(2)O(5) jars at 4°C and 22°C were all lower. A simple method of mouse sperm preservation is demonstrated. Three-O-methyl-D-glucose, a metabolically inactive derivative of glucose, offers significant protection for dried mouse sperm at above freezing temperatures without the need for poration of cell membrane.
Silicone Adhesive, a Better Matrix for Tolterodine Patches-a Research Based on in Vitro/in Vivo Studies
To design and optimize a drug-in-adhesive (DIA) type transdermal patch for tolterodine (TOL) based on acrylic and silicone matrixes.
Optimization of Glucose Feeding Approaches for Enhanced Glucosamine and N-acetylglucosamine Production by an Engineered Escherichia Coli
In this work, a recombinant Escherichia coli was constructed by overexpressing glucosamine (GlcN) synthase and GlcN-6-P N-acetyltransferase for highly efficient production of GlcN and N-acetylglucosamine (GlcNAc). For further enhancement of GlcN and GlcNAc production, the effects of different glucose feeding strategies including constant-rate feeding, interval feeding, and exponential feeding on GlcN and GlcNAc production were investigated. The results indicated that exponential feeding resulted in relatively high cell growth rate and low acetate formation rate, while constant feeding contributed to the highest specific GlcN and GlcNAc production rate. Based on this, a multistage glucose supply approach was proposed to enhance GlcN and GlcNAc production. In the first stage (0-2 h), batch culture with initial glucose concentration of 27 g/l was conducted, whereas the second culture stage (2-10 h) was performed with exponential feeding at μ (set) = 0.20 h⁻¹, followed by feeding concentrated glucose (300 g/l) at constant rate of 32 ml/h in the third stage (10-16 h). With this time-variant glucose feeding strategy, the total GlcN and GlcNAc yield reached 69.66 g/l, which was enhanced by 1.59-fold in comparison with that of batch culture with the same total glucose concentration. The time-dependent glucose feeding approach developed here may be useful for production of other fine chemicals by recombinant E. coli.
Silencing of the DEK Gene Induces Apoptosis and Senescence in CaSki Cervical Carcinoma Cells Via the Up-regulation of NF-κB P65
The human DEK proto-oncogene has been found to play an important role in autoimmune disease, viral infection and human carcinogenesis. Although it is transcriptionally up-regulated in cervical cancer, its intracellular function and regulation is still unexplored. In the present study, DEK and IκBα [inhibitor of NF-κB (nuclear factor κB) α] shRNAs (short hairpin RNAs) were constructed and transfected into CaSki cells using Lipofectamine™. The stable cell line CaSki-DEK was obtained after G418 selection. CaSki-IκB cells were observed at 48 h after psiRNA-IκB transfection. The inhibitory efficiency of shRNAs were detected by RT (reverse transcription)-PCR and Western blot analysis. The proliferation activity of cells were measured using an MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide] assay, cell apoptosis was measured using an Annexin V/PI (propidium iodide) kit, the cell cycle was analysed by flow cytometry and cell senescence was detected using senescence β-galactosidase staining. The intracellular expression of NF-κB p65 protein was studied by cytochemistry. The expression levels of NF-κB p65, p50, c-Rel, IκBα and phospho-IκBα protein were analysed by immunoblotting in whole-cell lysates, cytosolic fractions and nuclear extracts. The protein expression and activity of p38 and JNK (c-Jun N-terminal kinase) were also assayed. In addition, the NF-κB p65 DNA-binding activity was measured by ELISA. Following the silencing of DEK and IκBα, cell proliferation was inhibited, apoptosis was increased, the cell cycle was blocked in the G0/G1-phase with a corresponding decrease in the G2/M-phase, and cell senescence was induced. All of these effects may be related to the up-regulation of NF-κB p65 expression and its nuclear translocation.
Analysis of the Current Situation Regarding the Aging Rural Population in China and Proposed Countermeasures
Abstract China has become a country with an aging population. Compared with the aged in urban areas, the aged in rural areas have low income and are subject to social security deficiencies; the oldest among them are the most vulnerable group. If an effective mechanism for handling health risk is not available, the poor health of the rural elderly will cause an increase in their poverty level, which in turn will cause their health to become worse. Therefore, it is essential to analyze the current situation regarding rural population aging in China and to develop countermeasures. Data from 4 national health services surveys were used to analyze the differences between urban and rural populations. The results of the analysis revealed that the aged population in rural areas has poor health; economic security for the aged population is insufficient; and resources for the aged are lacking in rural areas. The Chinese government should improve medicare for the aged in rural areas, and establish a medical treatment subsidy system and a medical support system for the aged in rural areas. (Population Health Management 2012;15:xx-xx).
Oncogene-induced Senescence Results in Marked Metabolic and Bioenergetic Alterations
Oncogene-induced senescence (OIS) is characterized by permanent growth arrest and the acquisition of a secretory, pro-inflammatory state. Increasingly, OIS is viewed as an important barrier to tumorgenesis. Surprisingly, relatively little is known about the metabolic changes that accompany and therefore may contribute to OIS. Here, we have performed a metabolomic and bioenergetic analysis of Ras-induced senescence. Profiling approximately 300 different intracellular metabolites reveals that cells that have undergone OIS develop a unique metabolic signature that differs markedly from cells undergoing replicative senescence. A number of lipid metabolites appear uniquely increased in OIS cells, including a marked increase in the level of certain intracellular long chain fatty acids. Functional studies reveal that this alteration in the metabolome reflects substantial changes in overall lipid metabolism. In particular, Ras-induced senescent cells manifest a decline in lipid synthesis and a significant increase in fatty acid oxidation. Increased fatty acid oxidation results in an unexpectedly high rate of basal oxygen consumption in cells that have undergone OIS. Pharmacological or genetic inhibition of carnitine palmitoyltransferase 1, the rate-limiting step in mitochondrial fatty acid oxidation, restores a pre-senescent metabolic rate and, surprisingly, selectively inhibits the secretory, pro-inflammatory state that accompanies OIS. Thus, Ras-induced senescent cells demonstrate profound alterations in their metabolic and bioenergetic profiles, particularly with regards to the levels, synthesis and oxidation of free fatty acids. Furthermore, the inflammatory phenotype that accompanies OIS appears to be related to these underlying changes in cellular metabolism.
