No description available.

Angiopoietin-1 (Ang-1), the main ligand for the endothelial cell (EC)-selective Tie-2 receptors, promotes survival, proliferation, migration and differentiation of these cells. Despite its importance in various aspects of vascular biology, the mechanisms of action of the Ang-1/Tie-2 receptor pathway have not been fully explored. / To identify the downstream modulators of Ang-1, we evaluated changes in the transcriptome of human umbilical vein endothelial cells (HUVECs) treated with Ang-1 protein for four hours by employing the oligonucleotide rnicroarray technology. Eighty-six genes were significantly upregulated by this treatment and forty-nine genes were significantly downregulated. These genes are involved in the regulation of cell cycle, proliferation, apoptosis, transcription and differentiation. Furthermore, we found that the Erk1/2, PI3-Kinase and mTOR pathways are implicated in promoting gene expression in HUVECs in response to Ang-1. Analysis of the microarray data employing the Ingenuity Pathways analysis software to place the regulated genes in the context of biological networks revealed several highly connected nodes including the chemokine Interleukin-8 (IL-8) and the transcription factor Early growth response-1 (Egr-1). Due to the importance of these genes in promoting angiogenesis, we decided to evaluate their roles in Ang-1/Tie-2 receptor signaling and biological effects. / Ang-1 induced IL-8 expression in a time- and dose-dependent manner in ECs through both transcriptional and post-transcriptional mechanisms. To study the functional role of Ang-1-induced IL-8, we generated HUVECs that overexpress Ang-1. In these cells, neutralizing IL-8 significantly reduced EC proliferation and migration. IL-8 promoter activity experiments and gel shift assays revealed the involvement of the transcription factor AP-1 in Ang-1-induced IL-8. Ang-1 stimulated the phosphorylation of c-Jun through activation of Erk1/2, JNK and PI-3 kinase pathways. Similarly, Ang-1 provoked the expression and DNA binding of Egr-1 in HUVECs. Employing siRNA and DNAzyme to specifically knock-down Egr-1, we found that Ang-1-induced Egr-1 also promotes EC proliferation and migration. / We conclude that Ang-1 provokes a coordinated response intended to promote EC survival, proliferation, and angiogenesis and to inhibit EC apoptosis. Ang-1 induces EC proliferation and migration in part through the secretion of the soluble mediator Interleukin-8 and through induction of the transcription factor Egr-1.

Circulating lactate levels are a critical biomarker for sepsis and are positively correlated with sepsis-associated mortality. We investigated whether lactate plays a biological role in causing endothelial barrier dysfunction in sepsis. We showed that lactate causes vascular permeability and worsens organ dysfunction in CLP sepsis. Mechanistically, lactate induces ERK-dependent activation of calpain1/2 for VE-cadherin proteolytic cleavage, leading to the enhanced endocytosis of VE-cadherin in endothelial cells. In addition, we found that ERK2 interacts with VE-cadherin and stabilizes VE-cadherin complex in resting endothelial cells. Lactate-induced ERK2 phosphorylation promotes ERK2 disassociation from VE-cadherin. In vivo suppression of lactate production or genetic depletion of lactate receptor GPR81 mitigates vascular permeability and multiple organ injury and improves survival outcome in polymicrobial sepsis. Our study reveals that metabolic cross-talk between glycolysis-derived lactate and the endothelium plays a critical role in the pathophysiology of sepsis.

No description available.

Cellular defense and metabolism are important biological processes in living cells. In this study, these two biological processes were investigated in two selected disease models: diabetes mellitus (DM) and severe acute respiratory syndrome associated coronavirus (SARS-CoV) infection by two-dimensional gel electrophoresis (2DE) coupled with Matrix-Assisted Laser Desorption Ionisation Time-Of-Flight Mass Spectrometry (MALDI-TOF MS)-based proteomic approaches. The major findings are summarized as follows: / Our results on DM investigation can help to better understand the pathophysiological changes in patients with DM and the pathogenesis of hyperglycemia-caused complications. Data obtained from SARS-CoV studies provided novel insights into the molecular basis of the host cell response upon viral infection. / Protein profile of streptozotocin (STZ)-induced diabetic animal tissues, including mice liver, kidney and eye, and rats sera, indicated that DM has an impaired cellular defense system. These include the impairment in reactive oxygen species scavenging and the impairment in activation of complement system and innate immunity, and the enhancement in blood coagulation reaction. Our results also demonstrated that glycolysis and gluconeogenesis did not alter significantly in the liver of STZ-diabetic mice, while fatty acid oxidation and TCA cycle were attenuated under the same conditions. Moreover, we also detected other abnormal metabolism in aldehyde and amino acid, especially glutamate metabolism and the urea cycle. Abnormalities were also detected in lipid transport and metabolism. Besides, protein profile of mouse liver c37 cells indicated that high glucose may induce apoptosis in these cells, and this apoptotic effect may be mediated via the mitochondrial pathway. Furthermore, the proteomic results from the in vivo and in vitro diabetic models have prompted us to look for glucose responsive element on the promoters of these up-regulated hepatic genes. We found that the mouse aldolase 2 gene has glucose responsiveness in c37 cells treated with high glucose by semi-quantitative RT-PCR and promoter transfection assay. Finally, protein profile of Vero E6 cells strongly implicated that SARS-CoV can induce anti-apoptosis. This effect may be mediated via the mitochondrial pathway. Our data also suggested that the anti-apoptotic activity may be required for viral replication at the early stage of infection. While under the condition of long-term infection, this may be needed for viral survival. / Zhong Mingqi. / "October 2005." / Advisers: Sai Ming Ngai; Hon Ki Cheng. / Source: Dissertation Abstracts International, Volume: 67-11, Section: B, page: 6217. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (p. 223-248). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.

Wong, Wai Yin. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (leaves 92-108). / Abstracts in English and Chinese. / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Atherosclerosis --- p.1 / Chapter 1.1.1 --- Pathogenesis of Atherosclerosis --- p.2 / Chapter 1.1.2 --- Atherosclerosis and Cardiovascular Disease --- p.4 / Chapter 1.2 --- Cardiovascular Disease (CVD) --- p.5 / Chapter 1.2.1 --- Term Definition --- p.5 / Chapter 1.2.2 --- Risk Factors --- p.6 / Chapter 1.2.3 --- Current Western Medications --- p.7 / Chapter 1.3 --- Reactive Oxygen Species (ROS) --- p.8 / Chapter 1.3.1 --- Impact of ROS --- p.8 / Chapter 1.3.2 --- "Superoxide Anion Radical, Hydrogen Peroxide, Hydroxyl Radical, Nitric Oxide" --- p.9 / Chapter 1.3.3 --- ROS Production by NAD(P)H Oxidases --- p.11 / Chapter 1.3.4 --- ROS Production by Mitochondria --- p.12 / Chapter 1.3.5 --- Lipid Peroxidation --- p.13 / Chapter 1.3.6 --- Other Sources of ROS --- p.15 / Chapter 1.4 --- Antioxidants --- p.16 / Chapter 1.4.1 --- Superoxide Dismutase (SOD) --- p.16 / Chapter 1.4.2 --- Catalase (CAT) --- p.17 / Chapter 1.4.3 --- Glutathinoe Peroxidase (GPx) --- p.17 / Chapter 1.4.4 --- Glutathione-S-Transferase (GST) --- p.18 / Chapter 1.4.5 --- Vitamin E --- p.18 / Chapter 1.4.6 --- Vitamin C --- p.19 / Chapter 1.5 --- Ageing --- p.19 / Chapter 1.6 --- Antioxidants and CVD --- p.21 / Chapter 1.7 --- Traditional Chinese Medicine (TCM) --- p.22 / Chapter 1.7.1 --- Danshen --- p.23 / Chapter 1.7.2 --- Gegen --- p.25 / Chapter 1.7.3 --- Danshen-Gegen Compound Formula (DG) --- p.26 / Chapter 1.8 --- Aim of Study --- p.27 / Chapter Chapter 2 --- In vitro Foam Cells Formation --- p.29 / Chapter 2.1 --- Materials and Methods --- p.29 / Chapter 2.1.1 --- Materials --- p.29 / Chapter 2.1.2 --- Methods --- p.30 / Chapter 2.1.2.1 --- Herbal Preparation by Hot Water Extraction --- p.30 / Chapter 2.1.2.2 --- Resident Peritoneal Macrophages Preparation --- p.31 / Chapter 2.1.2.3 --- "Colorimetric 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl Tetrazolium Bromide (MTT) Assay" --- p.31 / Chapter 2.1.2.4 --- DG Effect on in vitro Foam Cells Formation --- p.32 / Chapter 2.2 --- Results and Discussion --- p.32 / Chapter 2.3 --- Summary --- p.39 / Chapter Chapter 3 --- In vivo Antioxidant Level --- p.40 / Chapter 3.1 --- DG Effect on in vivo Antioxidant Levels on Young-adult Wistar Rats --- p.40 / Chapter 3.1.1 --- Materials and Methods --- p.40 / Chapter 3.1.1.1 --- Herbal Preparation by Hot Water Extraction --- p.40 / Chapter 3.1.1.2 --- Assay Kits --- p.41 / Chapter 3.1.1.3 --- Antibodies for Protein Expression Determination in Organs --- p.41 / Chapter 3.1.1.4 --- Animals and Experimental Design --- p.41 / Chapter 3.1.1.5 --- Plasma Antioxidants --- p.42 / Chapter 3.1.1.6 --- Lipid Peroxidation and Protein Expression in Organs --- p.46 / Chapter 3.1.1.7 --- Statistics --- p.52 / Chapter 3.1.2 --- Results and Discussion --- p.53 / Chapter 3.2 --- DG Effect on in vivo Antioxidant Levels on Middle-aged Wistar Rats --- p.74 / Chapter 3.2.1 --- Materials and Methods --- p.75 / Chapter 3.2.2 --- Results and Discussion --- p.75 / Chapter 3.3 --- Summary --- p.87 / Chapter Chapter 4 --- Conclusion and Future Work --- p.90 / Chapter 4.1 --- Conclusion --- p.90 / Chapter 4.2 --- Future work --- p.90 / Reference --- p.92 / Related Publication --- p.109

Neste trabalho são apresentados os ensaios realizados para a caracterização da cultura de Rauvolfia sellowii Müll. Arg. (Apocynaceae). Foram determinados os parâmetros: pH, peso fresco, peso seco, produção de alcalóides, e consumo de açúcares. A curva de crescimento foi similar às observadas para as culturas de células de outras espécies, estendendo-se até o dia 14. As culturas de R. sellowii não converteram a sacarose em glicose e frutose no meio de cultura. A sacarose foi absorvida diretamente do meio. A absorção completou-se no dia 22. Não houve mudança significativa no pH do meio durante o desenvolvimento celular. A vomilenina foi identificada como o alcalóide majoritário. As alterações na produção deste alcalóide foram avaliadas pela modificações nas condições de cultivo, supressão de auxinas, aumento da concentração de sacarose e mio-inositol, adição de extrato de levedura (eliciador biótico), e adição dos precursores triptofano e triptamina. Em todos os casos houve a supressão da produção de vomilenina. Com exceção da adição de precursores, os tratamentos provocaram o acúmulo de substâncias desconhecidas, possivelmente outros alcalóides. / This work aimed to characterize the growth parameters of a Rauvolfia sellowii Müll. Arg. (Apocynaceae) cell suspension culture. The parameters analyzed were pH variation, biomass accumulation (fresh weight and dry weight), production of alkaloids and sugars uptake. The growth curve was similar to that observed for other plant cells, the culture cycle lasted for 14 days. R. sellowii cultures did not converted sucrose into glucose and fructose in the culture medium. Sucrose was directly taken up from the medium. The complete uptake occurred at day 22. There were no significant changes in the medium pH during the cell development. The major alkaloid accumulated in the cultures was characterized as the vomilenine. The regulation of vomilenine production was also evaluated by changing the culture conditions: depletion of auxins, increase of sucrose and myo-inositol concentration, addition elicitor (yeast extract) and precursor feeding (tryptophan and tryptamine). In all the conditions tested, vomilenine production was suppressed. Moreover, with the exception of precursor feeding, all treatments caused the accumulation of unknown substances, possibly alkaloids.

Neste trabalho são apresentados os ensaios realizados para a caracterização da cultura de Rauvolfia sellowii Müll. Arg. (Apocynaceae). Foram determinados os parâmetros: pH, peso fresco, peso seco, produção de alcalóides, e consumo de açúcares. A curva de crescimento foi similar às observadas para as culturas de células de outras espécies, estendendo-se até o dia 14. As culturas de R. sellowii não converteram a sacarose em glicose e frutose no meio de cultura. A sacarose foi absorvida diretamente do meio. A absorção completou-se no dia 22. Não houve mudança significativa no pH do meio durante o desenvolvimento celular. A vomilenina foi identificada como o alcalóide majoritário. As alterações na produção deste alcalóide foram avaliadas pela modificações nas condições de cultivo, supressão de auxinas, aumento da concentração de sacarose e mio-inositol, adição de extrato de levedura (eliciador biótico), e adição dos precursores triptofano e triptamina. Em todos os casos houve a supressão da produção de vomilenina. Com exceção da adição de precursores, os tratamentos provocaram o acúmulo de substâncias desconhecidas, possivelmente outros alcalóides. / This work aimed to characterize the growth parameters of a Rauvolfia sellowii Müll. Arg. (Apocynaceae) cell suspension culture. The parameters analyzed were pH variation, biomass accumulation (fresh weight and dry weight), production of alkaloids and sugars uptake. The growth curve was similar to that observed for other plant cells, the culture cycle lasted for 14 days. R. sellowii cultures did not converted sucrose into glucose and fructose in the culture medium. Sucrose was directly taken up from the medium. The complete uptake occurred at day 22. There were no significant changes in the medium pH during the cell development. The major alkaloid accumulated in the cultures was characterized as the vomilenine. The regulation of vomilenine production was also evaluated by changing the culture conditions: depletion of auxins, increase of sucrose and myo-inositol concentration, addition elicitor (yeast extract) and precursor feeding (tryptophan and tryptamine). In all the conditions tested, vomilenine production was suppressed. Moreover, with the exception of precursor feeding, all treatments caused the accumulation of unknown substances, possibly alkaloids.

Coronavirus disease 2019 (COVID-19), an infectious respiratory disease propagated by a new virus known as Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2), has resulted in global healthcare crises. Emerging evidence from patients with COVID-19 suggests that endothelial cell damage plays a central role in COVID-19 pathogenesis and could be a major contributor to the severity and mortality of COVID-19. Like other infectious diseases, the pathogenesis of COVID-19 is closely associated with metabolic processes. Lactate, a potential biomarker in COVID-19, has recently been shown to mediate endothelial barrier dysfunction. In this review, we provide an overview of cardiovascular injuries and metabolic alterations caused by SARS-CoV-2 infection. We also propose that lactate plays a potential role in COVID-19-driven endothelial cell injury.

Thymic epithelial cells (TECs) are the main component of the thymic stroma, which supports T-cell proliferation and repertoire selection. Here, we demonstrate that Cbx4, a Polycomb protein that is highly expressed in the thymic epithelium, has an essential and non-redundant role in thymic organogenesis. Targeted disruption of Cbx4 causes severe hypoplasia of the fetal thymus as a result of reduced thymocyte proliferation. Cell-specific deletion of Cbx4 shows that the compromised thymopoiesis is rooted in a defective epithelial compartment. Cbx4-deficient TECs exhibit impaired proliferative capacity, and the limited thymic epithelial architecture quickly deteriorates in postnatal mutant mice, leading to an almost complete blockade of T-cell development shortly after birth and markedly reduced peripheral T-cell populations in adult mice. Furthermore, we show that Cbx4 physically interacts and functionally correlates with p63, which is a transcriptional regulator that is proposed to be important for the maintenance of the stemness of epithelial progenitors. Together, these data establish Cbx4 as a crucial regulator for the generation and maintenance of the thymic epithelium and, hence, for thymocyte development.