Thesis (M.S.)--University of Missouri--Columbia, 2004. / Typescript. Includes bibliographical references (leaves 97-111). Also issued on the Internet.

Thesis (M.Sc.)--Memorial University of Newfoundland, Faculty of Medicine, 1999. / Typescript. Bibliography: leaves 113-124.

Knowledge of the dissociation constants of the ionizable protons of weak acids in aqueous media is of fundamental importance in many areas of chemistry and biochemistry. The pKa value, or equilibrium dissociation constant, of a molecule determines the relative concentration of its protonated and deprotonated forms at a specified pH and is therefore an important descriptor of its chemical reactivity. Considerable efforts have been devoted to the determination of pKa values by different experimental techniques. Although in most cases the determination of pKa values from experimental is straightforward, there are situations where interpretation is difficult and the results ambiguous. It is, therefore, not surprising that the capability to provide accurate estimates of the pKa value has been a central goal in theoretical chemistry and there has been a large effort in developing methodologies for predicting pKa values for a variety of chemical systems by differing quantum chemical techniques. A prediction accuracy within 0.5 pKa units of experiment is the desirable level of accuracy. This is a non-trivial exercise, for an error of 1 kcal/mol in estimates of the free energy value would result in an error of 0.74 pKa units. In this thesis ab initio Car-Parrinello molecular dynamics (CPMD) has been used for investigating the Brϕnsted acid-base chemistry of weak acids in aqueous solution. A key issue in any dissociation event is how the solvating water molecules arrange themselves spatially and dynamically around the neutral and dissociated acid molecule. Ab initio methods have the advantage that all solvent water molecules can, in principle, be con- sidered explicitly. One of the factors that has inhibited the widespread use of ab initio MD methods to study the dissociation reaction is that dissociation of weak acids are rare events that require extremely long simulation times before one is observed. The metady- namics formalism provides a solution to this conundrum by preventing the system from revisiting regions of configuration space where it has been in the past. The formalism allows the system to escape the free-energy minima by biasing the dynamics with a history dependent potential (or force) that acts on select degrees of freedom, referred to as collective variables. The bias potentials, modeled by repulsive inverted Gaussians that are dropped during propagation, drive the system out of any free-energy minima and allow it to explore the configurational space by a relatively quick and efficient sampling. The the- sis deals with a detailed investigation of the Brϕnsted acid-base chemistry of weak acids in aqueous solutions by the CPMD-metadynamics procedure. In Chapter 1, current approaches for the theoretical estimation of pKa values are summarized while in Chapter 2 the simulation methodology and the metadynamics sampling techniques used in this study are described. The potential of the CPMD-metadynamics procedure to provide estimates of the acid dissociation constant (pKa) is explored in Chapter 3, using acetic acid as a test sys- tem. Using the bond-distance dependent coordination number of protons bound to the dissociating carboxylic groups as the collective variable, the free-energy profile for the dissociation reaction of acetic acid in water was computed. Convergence of the free-energy profiles and barriers for the simulations parameters is demonstrated. The free-energy profiles exhibit two distinct minima corresponding to the dissociated and neutral states of the acid and the deterrence in their values provides the estimate for pKa. The estimated value of pKa for acetic acid from the simulations, 4.80, is in good agreement with the experiment at value of 4.76. It is shown that the good agreement with experiment is a consequence of the cancellation of errors, as the pKa values are computed as the divergence in the free energy values at the minima corresponding to the neutral and dissociated state. The chapter further explores the critical factors required for obtaining accurate estimates of the pKa values by the CPMD-metadynamics procedure. It is shown that having water molecules sufficient to complete three hydration shells as well as maintaining water density in the simulation cell as close to unity is important. In Chapter 4, the CPMD-metadynamics procedure described in Chapter-3 has been used to investigate the dissociation of a series of weak organic acids in aqueous solutions. The acids studied were chosen to highlight some of the major factors that influence the dissociation constant. These include the influence of the inductive effect, the stabilization of the dissociated anion by H-bonding as well as the presence of multiple ionizable groups. The acids investigated were aliphatic carboxylic acids, chlorine-substituted carboxylic acids, cis- and trans-butenedioic, the isomers of hydroxybenzoic acid and ophthalmic acids and its isomers. It was found that in each of these examples the CPMD-metadynamics procedure correctly estimates the pKa values, indicating that the formulism is capable of capturing these influences and equally importantly indicating that the cancellation of errors is indeed universal. Further, it is shown that the procedure can provide accurate estimates of the successive pKa values of polypro tic acids as well as the subtle difference in their values for different isomers of the acid molecule. Changes in protonation-deprotonation of amino acid residues in proteins play a key role in many biological processes and pathways. It is shown that CPMD simulations in conjunction with metadynamics calculations of the free energy profile of the protonation- deprotonation reaction can provide estimates of the multiple pKa values of the 20 canonical α-amino acids in aqueous solutions in good agreement with experiment (Chapter 5). The distance-dependent coordination number of the protons bound to the hydroxyl oxygen of the carboxylic and the amine groups is used as the collective variable to explore the free energy profiles of the Brϕnsted acid-base chemistry of amino acids in aqueous solutions. Water molecules, sufficient to complete three hydration shells surrounding the acid molecule were included explicitly in the computation procedure. The method works equally well for amino acids with neutral, acidic and basic side chains and provides estimates of the multiple pKa values with a mean relative error with respect to experimental results, of 0.2 pKa units. The tripeptide Glutathione (GSH) is one of the most abundant peptides and the major repository for non-protein sulfur in both animal and plant cells. It plays a critical role in intracellular oxidative stress management by the reversible formation of glutathione disulfide with the thioldisulfide pair acting as a redox buffer. The state of charge of the ionizable groups of GSH can influences the redox couple and hence the pKa value of the cysteine residue of GSH is critical to its functioning. In Chapter 6, it has been reported that ab initio Car-Parrinello Molecular Dynamics simulations of glutathione solvated by 200 water molecules, all of which are considered in the simulation. It is shown that the free-energy landscape for the protonation - deprotonation reaction of the cysteine residue of GSH computed using metadynamics sampling provides accurate estimates of the pKa and correctly predicts the shift in the dissociation constant values as compared to the isolated cysteine amino acid. The dissociation constants of weak acids are commonly determined from pH-titration curves. For simple acids the determination of the pKa from the titration curves using the Henderson-Hasselbalch equation is relatively straightforward. There are situations, however, especially in polyprotic acids with closely spaced dissociation constants, where titration curves do not exhibit clear inflexion and equivalence stages and consequently the estimation of multiple pKa values from a single titration curve is no longer straightfor- ward resulting in uncertainties in the determined pKa values. In Chapter 7, the multiple dissociation constant of the hexapeptide glutathione disulfide (GSSG) with six ionizable groups and six associated dissociation constants has been investigated. The six pKa values of GSSG were estimated using the CPMD-metadynamics procedure from the free-energy profiles for each dissociation reaction computed using the appropriate collective variable. The six pKa values of GSSG were estimated and the theoretical pH-titration curve was then compared with the experimentally measured pH-titration curve and found to be in excellent agreement. The object of the exercise was to establish whether interpretation of pH-titration curves of complex molecules with multiple ionizable groups could be facilitated using results of ab initio molecular dynamics simulations.

Besides the molecular mechanisms regulating activation of FLS mentioned above, we also investigated anti-inflammatory activities of Chinese herbal medicine sinomenine and Liang Miao San on activated human FLS in RA. Sinomenine, an alkaloid isolated from the root of Sinomenium acutum, has been used to alleviate the symptoms of rheumatic diseases. Liang Miao San (LMS), composed of the herbs Rhizoma Atractylodis (Cangzhu) and Cotex Phellodendri (Huangbai), is another traditional Chinese medicine formula for RA treatment. Since the potential anti-inflammatory activities of sinomenine and LMS have been demonstrated, we investigated the in vitro anti-inflammatory effects of sinomenine and LMS on inflammatory cytokine TNF-alpha activation of human normal and RA-FLS and the underlying intracellular mechanisms. In the present study, sinomenine was found to significantly inhibit TNF-alpha induced cell surface expression of VCAM-1 and release of inflammatory cytokine and chemokine IL-6, CCL2 and CXCL8 from both normal and RA-FLS (all p < 0.05). Our results provide a new insight into the differential anti-inflammatory activities of sinomenine and LMS through the suppression of TNF-alpha activated FLS by modulating distinct intracellular signaling pathways in RA, and help to provide a biochemical basis for the development of a cost-effective human synoviocyte model for the future screening of traditional Chinese medicine (TCM) possessing potential anti-rheumatic activities. (Abstract shortened by UMI.) / IL-27, a novel member of the IL-12 family that is produced early by antigen-presenting cells (APCs), can promote T cell proliferation as well as the production of interferon-gamma by naive T lymphocytes. Recent studies have found that elevated expression of IL-27 has been detected in the synovial membranes and fluid of RA. Herein we investigated the in vitro effects of IL-27, alone or in combination with inflammatory cytokine TNF-alpha or IL-Ibeta on the pro-inflammatory activation of human primary FLS isolated from RA patients and normal control subjects, and the underlying intracellular signaling molecules were also studied. We found that the plasma concentration of IL-27 in RA patients (n=112) was significantly higher than that in control subjects (n=46). Both normal and RA-FLS constitutively express functional IL-27 receptor heterodimer, gp130 and WSX-1, with more potent IL-27-mediated activation of signal transducers and activators of transcription (STAT)1 in RA-FLS. IL-27 was found to induce significantly higher cell surface expression of intercellular adhesion molecule (ICAM)-1 and vascular cell adhesion molecule (VCAM)-1 and release of inflammatory cytokine IL-6, chemokine CCL2, CXCL9, CXCL10 and matrix metalloproteinase (MMP)-1 of RA-FLS than that of normal FLS (all p < 0.05). The above findings therefore provide a new insight into the IL-27-activated immunopathological mechanisms mediated by distinct intracellular signal transductions in joint inflammation of RA and may have important therapeutic implications. / In the present study, we have investigated the mechanisms of the activation of human fibroblast-like synoviocytes (FLS) induced by various stimuli including interleukin (IL)-27, tumor necrosis factor (TNF)-alpha and IL-beta. The activation of human FLS was studied in terms of the release of cytokines and chemokines and the expression of adhesion molecules. / We investigated the in vitro effects of uric acid crystals, alone or in combination with inflammatory cytokine TNF-alpha or IL-beta on the pro-inflammatory activation of human FLS from RA patients and normal control subjects, and the underlying intracellular signaling molecules were also determined. In the present study, uric acid crystals were found to result in a significant increase of inflammatory cytokine IL-6, chemokine CXCL8 and MMP-1 from both normal and RA-FLS (all p < 0.05). Moreover, additive or synergistic effect was observed in the combined treatment of uric acid crystals and TNF-alpha or IL-1beta on the release of IL-6, CXCL8 and MMP-1 from both normal and RA-FLS. Further investigations showed that the release of inflammatory cytokine, chemokine and matrix metalloproteinase stimulated by uric acid crystals was differentially regulated by intracellular activation of extracellular signal-regulated kinase (ERK) and JNK pathways. Our results therefore provide a new insight into the endogenous danger signal uric acid crystals-activated immunopathological mechanisms mediated by distinct intracellular signal transductions in joint inflammation, and also provide biochemical basis for the development of new modality for inflammatory rheumatic diseases. / Chen, Dapeng. / Adviser: Wong Chun Kwok. / Source: Dissertation Abstracts International, Volume: 73-04, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 203-240). / 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, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

Li Qing. / "July 2004." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (p. 161-192). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

Airway bronchial epithelial cells play important roles in host defense, inflammation and regulation of immune responses. Activated bronchial epithelial cells are potent sources of a wide variety of soluble and cell-surface molecules that can alter the biological functions of inflammatory cells in the airways. Molecular mechanisms regulating the production of inflammatory mediators from bronchial epithelial cells remain to be fully elucidated. / All of the above findings suggest that human bronchial epithelial cells could be activated by a variety of stimuli in airway inflammatory reactions. Besides, different intracellular signaling pathways could regulate the activation of human bronchial epithelial cells in response to different stimuli. Our results therefore provide new insight into the molecular mechanisms involved in airway inflammatory diseases and may have important therapeutic implications. / Basophils are the accessory cell type required for T helper (Th)2 induction and initiators in IgE-mediated chronic allergic inflammation in response to allergens. Number of basophils and Th17 cells increases at the sites of allergic inflammation in the airways of allergic asthmatic patients. To elucidate the interaction among the activation of human bronchial epithelial cells, Th17 cells, and basophils, we investigated the activation effects of Th17 hallmark cytokine IL-17A on the human primary bronchial epithelial cells/BEAS-2B bronchial epithelial cells and human primary basophils/ KU812 basophilic cells. Human bronchial epithelial cells and basophils were cultured either together or separately in the presence or absence of IL-17A stimulation. Co-culture of human bronchial epithelial cells and basophils could significantly increase the release of inflammatory cytokine IL-6 and mononuclear chemoattractant protein-1 (MCP-1/CCL2), a chemokine for basophils, eosinophils and monocytes, while human bronchial epithelial cells were the main source for releasing IL-6 and CCL2. Such induction was synergistically enhanced upon the activation of IL-17A. The use of transwell inserts in the co-culture system demonstrated that the direct interaction between these two cell types was necessary for IL-6 and CCL2 release induced by IL-17A. Surface expression of intercellular adhesion molecule-1 (ICAM-1) on the human bronchial epithelial cells was also up-regulated upon their interaction. The interaction of human bronchial epithelial cells and basophils under IL-17A stimulation was differentially regulated by extracellular signal-regulated kinase (ERK), c-Jun N-terminal protein kinase (JNK), p38 mitogen activated protein kinase (MAPK) and nuclear factor (NF)-kappaB pathways. Our findings therefore suggest a novel immunopathological role of human Th17 cells and basophils in allergic asthma through the activation of granulocytes-mediated inflammation initiated by the direct interaction between human basophils and bronchial epithelial cells. / IL-27 is a novel member of the IL-6/IL-12 family cytokines that are produced early by antigen-presenting cells (APCs) during immune responses. IL-27 can drive the commitment of naive T cells to a Th1 phenotype and inhibit inflammation in later phases of infection. Recent evidence has suggested that human bronchial epithelial cells with the expression of IL-27 receptor complex are potential target cells of IL-27. Here we investigated the in vitro effects of IL-27, alone or in combination with inflammatory cytokine TNF-alpha on the pro-inflammatory activation of human bronchial epithelial cells, and the underlying intracellular signaling molecules were also studied. IL-27 was found to up-regulate ICAM-1 expression on the surface of human bronchial epithelial cells, and a synergistic effect was observed in the combined treatment of IL-27 and TNF-alpha on the surface expression of ICAM-1. Although IL-27 did not alter the basal IL-6 secretion from human bronchial epithelial cells, it could significantly enhance TNF-alpha-induced IL-6 production. The synergistic effects on the induction of ICAM-1 and IL-6 were partially due to the up-regulated expression of TNF-alpha receptor (p55TNFR) on the surface of human bronchial epithelial cells induced by IL-27. Further investigations showed that the enhanced production of ICAM-1 and IL-6 in human bronchial epithelial cells activated by IL-27 and TNF-alpha was differentially regulated by phosphatidylinositol 3-OH kinase (PI3K)-Akt, p38 MAPK and NF-kappaB pathways. Our study therefore suggests a potential role of IL-27 and TNF-alpha in the pathogenesis of airway infection or inflammatory diseases. / In the present study, we investigated the mechanisms of the activation of human bronchial epithelial cells induced by various stimuli including interleukin (IL)-17A, IL-27, tumor necrosis factor (TNF)-alpha and human basophils. The activation of human bronchial epithelial cells was studied in terms of the expression of cytokines, chemokines and adhesion molecules. Using intracellular staining with flow cytometry and selective pharmacological inhibitors, we further investigated the underlying intracellular signaling mechanisms regulating the activation of human bronchial epithelial cells. / Cao, Ju. / Advisers: Chun K. Wong; Christopher W. K. Lam. / Source: Dissertation Abstracts International, Volume: 72-04, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 175-202). / 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 Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

L’interleukine (IL)-17 et le TNFa sont deux cytokines pro-inflammatoires jouant un rôle important dans diverses maladies inflammatoires systémiques et auto-immunes affectant différents organes et tissus comme le foie et les muscles. Cependant, les rôles de l’IL-17 et du TNFa restent encore mal compris dans les muscles et le foie, qui est impliqué dans la réponse en phase aiguë. En utilisant des cultures de myoblastes, d’hépatocytes et de cellules stellaires hépatiques humaines, nous avons trouvé que l’IL-17 et le TNFa augmentent en synergie la sécrétion de la cytokine pro-inflammatoire IL-6 et de plusieurs chimiokines. Dans les myoblastes, l’IL-17 et le TNFa induisent un stress oxydatif et une dérégulation de calcium montrant ainsi que les processus pathologiques immuns et non-immuns interagissent. Dans les hépatocytes, en augmentant en synergie les niveaux de la CRP et des transaminases, l’IL-17 et le TNFa participent à l’inflammation systémique et aux dommages cellulaires. Etant donné que des infiltrats de cellules immunitaires sont retrouvés lors d’atteintes inflammatoires, les interactions cellulaires contribuent certainement à la chronicité de l’inflammation. Des cellules mononuclées du sang périphérique activées ou non ont ainsi été placées en co-cultures avec les myoblastes, les hépatocytes et les cellules stellaires. Par comparaison aux monocultures, les productions de l’IL-6 et de la chimiokine IL-8 étaient augmentées dans les co-cultures. L’IL-17 et le TNFa contribuaient partiellement à ces effets. Les effets systémiques de l’IL-17 et du TNFa en font donc des cibles thérapeutiques attrayantes pour le traitement des nombreuses maladies inflammatoires systémiques / Interleukin-17A (IL-17) and tumor necrosis factor-a (TNFa) are two pro-inflammatory cytokines playing an important role in various systemic inflammatory and autoimmune disorders affecting different organs and tissues including the liver and the muscles. However, the roles of IL-17 and TNFa are not fully understood in the muscles and also in liver, which is crucial in the acute phase response. By using cultures of human myoblasts, primary human hepatocytes, human HepaRG cells and LX-2 hepatic stellate cells, we found that IL-17 and TNFa increase in synergy the production of the pro-inflammatory cytokine IL-6 and chemokines (IL-8, CCL20, MCP-1). In myoblasts, the IL-17 and TNFa stimulation induces endoplasmic reticulum stress and calcium dysregulation showing that immune and non-immune pathogenic mechanisms interplay. In hepatocytes, IL-17 and TNFa mediate systemic inflammation and cell damage by increasing in synergy the CRP acute-phase protein and transaminase levels through the induction of IL-6. Since active liver and muscle disorders are characterized by inflammatory infiltrates of immune cells, the cell interactions play certainly an important role in the chronicity of the inflammation. Peripheral blood mononuclear cells activated or not were therefore co-cultured with myoblasts, hepatocytes and/or hepatic stellate cells to assess the inflammatory role of the cell-cell interactions. Co-cultures enhance the production of IL-6 and IL-8 compared to monocultures. IL-17 and TNFa contribute partially to these inductions. The systemic effects of IL-17 and/or TNFa make them attractive therapeutic targets for the treatment of various systemic inflammatory disorders

Thesis (Ph.D. in Immunology) -- University of Colorado at Denver and Health Sciences Center, 2005. / Typescript. Includes bibliographical references (leaves 144-178). Free to UCDHSC affiliates. Online version available via ProQuest Digital Dissertations;

título de Ingeniería en Biotecnología Molecular / El virus Andes (ANDV) pertenece al género Orthohantavirus (familia Hantaviridae, orden Bunyavirales). En humanos la infección por ANDV produce el síndrome pulmonar asociado a hantavirus, el cual presenta una tasa de mortalidad de alrededor de un 35%. Estos virus se caracterizan por poseer una envoltura lipídica y un genoma de ARN de hebra simple tri-segmentado, de polaridad negativa que codifica para al menos 4 proteínas, entre ellas la proteína de nucleocápside (N) multifuncional y un precursor proteico denominado GPC, que tras ser procesado resulta en las glicoproteínas Gn y Gc que se encuentran ancladas en la envoltura viral. La apoptosis es una respuesta celular común frente a una infección viral. Sin embargo, en el ciclo replicativo de los hantavirus aún es controversial si inducen o inhiben apoptosis. La apoptosis celular puede ser inducida extrínsecamente mediante receptores de muerte específicos, que pueden ser activados por un ligando de la familia del factor de necrosis tumoral, como TRAIL (ligando inductor de apoptosis relacionado al factor de necrosis tumoral, por sus siglas en inglés) a través de una cascada de señalización, mediante un dominio de muerte. En este seminario de título, se buscó determinar si la expresión o localización del receptor de TRAIL, específicamente DR5 (receptor de muerte 5, por sus siglas en inglés) se ve alterada por la expresión de proteínas Gn, Gc y N de ANDV en células humanas, y si una posible variación podría afectar la tasa de apoptosis mediada por TRAIL. En primer lugar, se analizó la expresión de DR5 en distintos tipos celulares, y se determinó que éste receptor se expresa en mayor medida en células A549, por lo que para el resto de los análisis se continuó con esta línea celular. A continuación, se midió la expresión, tanto a nivel transcripcional como traduccional de DR5 en dependencia de ANDV Gn, Gc y N, frente a lo cual, no hubo una variación significativa en la expresión general de este receptor; sin embargo, en donde sí se encontró un incremento significativo fue en la localización de DR5 en la superficie de las células A549 en presencia de ANDV N. De todas formas, no se logró detectar inducción de apoptosis en células humanas transfectadas con ANDV N, lo cual no es posible interpretar debido a la carencia de un control positivo de apoptosis celular. En resumen, estos datos en conjunto muestran que a pesar de que la expresión de ANDV N indujo un aumento en la localización de DR5 en la superficie de células A549, sin embargo, queda por determinar si este aumento podría inducir apoptosis mediada por TRAIL. / Andes virus (ANDV) belongs to the Orthohantavirus genus (Hantaviridae family, Bunyavirales order). In humans ANDV infection causes hantavirus pulmonary syndrome, which has a fatality rate around 35%. These viruses are featured by a lipid envelope and a tri-segmented, single stranded, negative sense RNA genome, that encodes at least four proteins, among them, the multifunctional nucleocapsid protein (N) and a glycoprotein precursor termed GPC, which after being proteolytically cleaved, results in the mature glycoproteins Gn and Gc, which are anchored to the viral envelope. Apoptosis is a common cellular response against a viral infection. However, in the hantavirus replicative cycle, there is still controversy whether these viruses induce or rather block apoptosis. Apoptosis can be triggered extrinsically, through specific death receptors, that can be activated by a ligand belonging to the tumor necrosis factor family, such as TRAIL (tumor necrosis factor–related apoptosis inducing ligand), through a death domain mediated signaling cascade. During this degree seminary, we aimed to determine whether the expression or location of the TRAIL receptor DR5 (death receptor 5), is altered by ANDV Gc, Gn and N expression in human cells, and if any possible variation could affect TRAIL mediated apoptosis. First, we analyzed DR5 expression in different cell types and found that there is a higher extent of DR5 expression in A549 cells, that is why, for the rest of this seminary, we continued the work with this cell line. Next, we measured DR5 expression in these cells at a transcriptional and translational level, after being transfected with plasmids encoding ANDV Gc, Gn or N. We did not find any significant variation in the total amount of DR5 expression; nevertheless, we detected a significant increase in the location of DR5 on the surface of A549 cells in the presence of ANDV N. Although, we were unable to detect apoptosis in human cells transfected with ANDV N due to the lack of a positive control of apoptosis. Finally, all together, our results show that the expression of ANDV N induces an increase in DR5 on the surface of A549 cells, however, it has yet to be determined whether or not, this is enough to induce apoptosis mediated by TRAIL.

The redox state in the cell plays a major role in determining vital functions and its major imbalance can lead to severe cell injury or death. Redox active proteins and cytokines involved in this process includes thioredoxin (Trx), protein disulfide isomerase (PDI), and tumor necrosis factor (TNF) superfamilies. Trx is a multipotent protein and key regulator of cellular redox balance operating in synergy with Trx reductase and NADPH (the Trx system). Trx has gene regulatory activity of several transcription factors. It also controls in a fascinating way redox-sensitive “on-off” decisions for apoptotic or hypertrophic pathways. Trx protects against H2O2 and TNFmediated cytotoxicity, a pathway in which TNF receptor-binding generates ROS. TNF is an autocrine growth factor and survival factor in vitro and in vivo for B-type of chronic lymphocytic leukemia (B-CLL) cells. The overall aim of this study was to investigate the importance of redox active proteins and cytokines in inflammation and cancer. We focused on: i) the role of Trx, TrxR, and selenium in carcinogenesis and in resistant cancer cells. ii) the importance of Trx in cancer cells and the redox regulation of TNF and its receptors TNFR1 and TNFR2. iii) the potential role of Trx as a key regulator in cellular redox balance, in the pathogenesis of cardiac dysfunction; its relationship to stress response parameters. iv) whether unmutated CLL (UCLL) responses to PKC and ROS pathways were different from mutated CLL (M-CLL) responses. Our results demonstrate pronounced selective selenium-mediated apoptosis in therapy resistant cells and suggest that redox regulation through the Trx system is an important target for cancer therapy. Trx was strikingly elevated in heart failure cases compared with controls signifying an adaptive stress response that is higher the more severe the disease. TNF autocrine release was redox modulated and the TNF receptors interacted at the cell surface membrane with the redox-active PDI, which excerted a stringent redox-control of the TNFR signaling. The proliferative response as well as increase of autocrine TNF and Trx were higher in U-CLL than in M-CLL. The overall conclusion of the four papers included in this thesis is that redox-active proteins and cytokines plays an important role in control and regulation of cancer and inflammation. Furthermore, redox regulation via thioredoxin by selenium, may offer novel treatment possibilities for resistant tumors disease.