No description available.

O treinamento por natação leva a uma sobrecarga de volume no coração, que induz a hipertrofia cardíaca (HC) excêntrica, com aumento da massa e do diâmetro cardíaco. Neste trabalho foram investigadas as adaptações no sistema cardiovascular e na expressão de genes relacionados à HC patológica, na gênese da HC por treinamento de natação. 42 ratas wistar foram divididas em grupos: sedentário controle (SC) treinado protocolo 1 (P1) e treinado protocolo 2 (P2). O treinamento de P1 foi de 1x60min/dia, 5x/semana, por 10 semanas. O de P2 foi igual ao P1 até a 8ª semana. Na 9ª semana 2x/dia e na 10ª semana 3x/dia. Os grupos treinados, em relação ao SC, apresentaram bradicardia de repouso, melhora no desempenho físico do teste máximo e do consumo máximo de oxigênio e HC, sem alterar a pressão arterial média e a expressão dos genes do fator natriurético atrial e da alfa actina esquelética. O grupo P2 apresentou aumento no diâmetro cardíaco e redução da expressão do gene da beta miosina de cadeia pesada. Este último resultado é contrário à literatura para a HC patológica, que mostra o aumento não só da expressão deste gene como a dos outros genes estudados. Os resultados de HC de P2 assemelham-se aos encontrados em estudos recentes com atletas de modalidades de maior componente aeróbio, sendo este um bom modelo para investigação dos mecanismos envolvidos na HC destes atleta / Swimming training leads to a cardiac volume overload that induces excentric cardiac hypertrophy (CH) with an increase in cardiac mass and diameter. Cardiovascular system adaptations and expression of genes relatated with pathological CH were investigated in swimming training CH. We studied 42 wistar females, divided in sedentary control (SC) group, protocol 1 trained group (P1) and protocol 2 trained group (P2). The P1 training program was once a day for 5 times/week for 10 weeks. P2 was the same as P1 until 8th week. In 9th week it was twice a day and in 10th week 3 times a day. Trained groups, in contrast with SC, showed rest bradycardia, improvement in physical performance, maximum oxygen uptake and CH, with no alteration in the medium arterial pressure and in the expression of atrial natriuretic factor and skeletal alpha actin genes. Moreover, P2 showed an increase in cardiac diameter and decrease in the expression of beta myosin heavy chain gene. This expression result is different of patological CH literature wich shows an increase of this gene expression and also in the others genes we had investigated. P2 CH results were similar to those recently found in endurance-type athletes, sugesting this is a good model to investigate mechanisms involved in endurance-type athletes CH

Die ersten identifizierten Krankheitsgene der dilatativen Kardiomyopathie (DCM) kodierten alle für Proteine des Zytoskeletts. Deshalb wurde DCM als Erkrankung des Zytoskeletts bezeichnet. Bei der hypertrophen Kardiomyopathie (HCM) wurden bisher mehr als 250 Mutationen in neun Sarkomerprotein-Genen beschrieben. Deshalb wurde HCM als Erkrankung des Sarkomers bezeichnet. In den letzten Jahren wurde dieses Konzept durch Entdeckung von Mutationen in Sarkomerprotein-Genen bei DCM jedoch in Frage gestellt. Vor diesem Hintergrund haben wir die Sarkomerprotein-Gene beta-MHC und Troponin T bei 46 nicht verwandten DCM-Patienten untersucht. Das systematische Mutationsscreening wurde mit Hilfe von SSCP-Analyse und DNA-Sequenzierung durchgeführt. Im beta-MHC-Gen konnten wir die zwei Missense-Mutationen Ala223Thr und Ser642Leu bei zwei jungen Patienten identifizieren. Beide Mutationen wurden weder bei 136 HCM-Patienten noch bei 88 Kontrollen gefunden. Mit dem Editor for Structural Alignment of Proteins (STRAP) wurden die Mutationen auf die Proteinstruktur des Myosins projiziert. Hier ist erkennbar, dass Ala223Thr in der oberen 50 kDa Domäne und Ser642Leu in der Aktin-Myosin-Bindungsregion liegt. Der Austausch von Alanin zu Threonin könnte die Raumstruktur des Proteins verändern, Thermostabilität verringern und die Proteinfaltung und somit die Proteinmotilität beeinträchtigen. In der Aktin-Myosin-Bindungsregion liegt neben Ser642Leu die bereits bekannte DCM-assoziierte Mutation Ser532Pro. Durch eine Verminderung der Krafterzeugung könnten die beiden Mutationen zu DCM führen. Ferner wurden die zwei stummen Mutationen IVS11+23A>T und Asp376Asp und sechs Polymorphismen identifiziert. Im Troponin T-Gen wurden keine Mutationen, jedoch sechs Polymorphismen beobachtet. Es ergab sich kein Anhaltspunkt auf eine funktionelle Relevanz der stummen Mutationen oder Polymorphismen. Wir konnten also bestätigen, dass Mutationen in Sarkomerprotein-Genen sowohl zu HCM als auch zu DCM führen können. / All of the initially identified disease-causing genes in dilated cardiomyopathy (DCM) encoded proteins of the cytoskeleton. Therefore DCM has been termed a disease of the cytoskeleton. In hypertrophic cardiomyopathy (HCM) more than 250 mutations in nine sarcomeric protein genes have been identified so far. Therefore HCM has been termed a disease of the sarcomere. However, in the last few years this concept has been queried by findings of mutations in sarcomeric protein genes in DCM. According to this consideration we screened the sarcomeric protein genes beta-MHC and troponin T in 46 patients with DCM. Systematic mutation screening was done using SSCP analysis and DNA sequencing. In the beta-MHC gene we identified the two missense mutations Ala223Thr and Ser642Leu in two young patients. Both mutations were neither found in 136 HCM patients nor in 88 controls. Using the Editor for Structural Alignment of Proteins (STRAP) the mutations were projected onto the protein structure of myosin. Ala223Thr turned out to be localized in the upper 50 kDa domain and Ser642Leu in the actin-myosin-interface region. The exchange from alanine to threonine might alter the spatial structure of the protein, decrease its thermostability and affect the protein folding and thus the protein motility. Closely to Ser642Leu the DCM-associated mutation Ser532Pro is located in the actin-myosin-interface region. By a decrease in force production both mutations might cause DCM. Furthermore we identified the two silent mutations IVS11+23A>T and Asp376Asp and six polymorphisms. In the troponin T gene no mutations but six polymorphisms were detected. No evidence was found for functional relevance of the silent variants or polymorphisms. Thus, we could confirm that mutations in sarcomeric protein genes can lead to both HCM and DCM.

No description available.

The cytokine TRAIL is a promising cancer therapeutic candidate as it induces apoptosis selectively in transformed cells. TRAIL-induced clustering of its receptors (DR) is essential for the DISC complex formation, which induces cell death. The mechanism for TRAIL's tumour selective effect is largely unknown. We identified the cytoskeleton proteins non-muscle myosin heavy chain IIa, IIb (NMHCIIa, NMHCIIb), myosin regulatory light chain (MLC2) and ß-actin as novel DR-interactors. An initially weak and TRAIL-induced abrogation of NMHCII/DR interaction correlated with efficient DISC formation in tumour cells. In contrast, a robust NMHCII/DR interaction that was sustained upon TRAIL stimulus was accompanied by incomplete DISC arrangement. Weakening the NMHCII/DR interaction in normal cells using chemical inhibitors enhanced TRAIL-induced apoptosis. Intriguingly, siRNA-mediated NMHCIIa- but not NMHCIIb depletion potently released TRAIL resistance in normal cells and influenced DISC composition. Reduced NMHCII/DR interaction in transformed cells was characterised by diminished MLC2 phosphorylation and altered protein expression of upstream regulatory kinases. Our results suggest that normal cell resistance to TRAIL-apoptosis is based on the interaction of cytoskeleton components with DR that is impaired upon transformation. Since NMHCII function in cell adhesion and migration, it will be interesting to study possible roles of the interaction in cell detachment and altered TRAIL sensitivity; moreover this link may provide clues as to the cause of TRAIL resistance in some cancers.

O treinamento por natação leva a uma sobrecarga de volume no coração, que induz a hipertrofia cardíaca (HC) excêntrica, com aumento da massa e do diâmetro cardíaco. Neste trabalho foram investigadas as adaptações no sistema cardiovascular e na expressão de genes relacionados à HC patológica, na gênese da HC por treinamento de natação. 42 ratas wistar foram divididas em grupos: sedentário controle (SC) treinado protocolo 1 (P1) e treinado protocolo 2 (P2). O treinamento de P1 foi de 1x60min/dia, 5x/semana, por 10 semanas. O de P2 foi igual ao P1 até a 8ª semana. Na 9ª semana 2x/dia e na 10ª semana 3x/dia. Os grupos treinados, em relação ao SC, apresentaram bradicardia de repouso, melhora no desempenho físico do teste máximo e do consumo máximo de oxigênio e HC, sem alterar a pressão arterial média e a expressão dos genes do fator natriurético atrial e da alfa actina esquelética. O grupo P2 apresentou aumento no diâmetro cardíaco e redução da expressão do gene da beta miosina de cadeia pesada. Este último resultado é contrário à literatura para a HC patológica, que mostra o aumento não só da expressão deste gene como a dos outros genes estudados. Os resultados de HC de P2 assemelham-se aos encontrados em estudos recentes com atletas de modalidades de maior componente aeróbio, sendo este um bom modelo para investigação dos mecanismos envolvidos na HC destes atleta / Swimming training leads to a cardiac volume overload that induces excentric cardiac hypertrophy (CH) with an increase in cardiac mass and diameter. Cardiovascular system adaptations and expression of genes relatated with pathological CH were investigated in swimming training CH. We studied 42 wistar females, divided in sedentary control (SC) group, protocol 1 trained group (P1) and protocol 2 trained group (P2). The P1 training program was once a day for 5 times/week for 10 weeks. P2 was the same as P1 until 8th week. In 9th week it was twice a day and in 10th week 3 times a day. Trained groups, in contrast with SC, showed rest bradycardia, improvement in physical performance, maximum oxygen uptake and CH, with no alteration in the medium arterial pressure and in the expression of atrial natriuretic factor and skeletal alpha actin genes. Moreover, P2 showed an increase in cardiac diameter and decrease in the expression of beta myosin heavy chain gene. This expression result is different of patological CH literature wich shows an increase of this gene expression and also in the others genes we had investigated. P2 CH results were similar to those recently found in endurance-type athletes, sugesting this is a good model to investigate mechanisms involved in endurance-type athletes CH

No description available.

<p>Monoclonal antibodies (mAbs) as therapeutic proteins have shown great potential in treatment of various human diseases because of their highly specific nature. This has attracted worldwide attention leading to increased demand for such mAb products. To meet this demand large scale manufacturing is carried out using recombinant mammalian cell culture techniques for high yields and faster production. mAb products are worth the investment if produced in their native state. The quantity of mAb present in such cell cultures is very less and therefore special care is needed while handling them. Purifying antibody molecules from heterogeneous cell culture impurities and maintaining their native functional state is a critical task mainly because these antibodies are labile in nature. Care also need to be exercised during processing because mAbs have inherent tendancy to aggregate which is undesirable since such aggregates in antibody formulation produces immunogenic reaction when injected in humans. The other important factor in mAb purification is the processing cost involved since majority of the total production cost is utilized for purification of mAb. Protein-A chromatography is the first choice for purifying antibodies and is widely adopted. However failure in distinguishing between monomer and aggregate antibody molecules along with harsh acidic processing conditions necessitates the use of further purification steps.</p> <p>In this work various techniques for mAb processing are discussed and are outlined below:</p> <p>Removal of impurities from mAbs is a major challenge and this thesis discusses various processing options available to purify these mAbs. Impurities in mAb products are usually the aggregate byproducts formed due to unfolded monomer antibody molecules. These molecules are naturally hydrophobic in nature and display great differences in hydrophobicity on aggregation. Hydrophobic interaction membrane chromatography (HIMC) makes use of this hydrophobicity difference and helps in removal of aggregate impurities from monomer antibody.</p> <p>Heavy chain mAbs (hcmAbs) are promising new developments in the area of biopharmaceuticals because of their unique structural composition. Similar to conventional mAbs these hcmAbs are also rapidly finding their way into therapeutic markets. Purifying hcmAbs will be an important step in their development and for this purpose we use HIMC technique for removing impurities and obtain pure product.</p> <p>Antibody molecules are almost always lost as aggregates which leads to great economic losses and the ability to disaggregate these mAb oligomers would be of significant practical and scientific interest. In this work a novel thermalcycling technique is discussed to disaggregate such mAb oligomers and potentially recover functional monomer mAb molecules.</p> / Master of Applied Science (MASc)

Cardiovascular diseases are among the leading causes of death worldwide and particularly in the developed World. The search for new therapeutic approaches for improving the functions of the damaged heart is therefore a critical endeavour. Myocardial infarction, which can lead to heart failure, is associated with irreversible loss of functional cardiomyocytes. The loss of cardiomyocytes poses a major difficulty for treating the damaged heart since terminally differentiated cardiomyocytes have very limited regeneration potential. Currently, the only effective treatment for severe heart failure is heart transplantation but this option is limited by the acute shortage of donor hearts. The high incidence of heart diseases and the scarcity donor hearts underline the urgent need to find alternative therapeutic approaches for treating cardiovascular diseases. Pluripotent embryonic stem (ES) cells can differentiate into functional cardiomyocytes. Therefore the engraftment of ES cell-derived functional cardiomyocytes or cardiac progenitor cells into the damaged heart to regenerate healthy myocardial tissues may be used to treat damaged hearts. Stem cell-based therapy therefore holds a great potential as a very attractive alternative to heart transplant for treating heart failure and other cardiovascular diseases. A major obstacle to the realisation of stem cell-based therapy is the lack of donor cells and this in turn is due to the fact that, currently, the molecular mechanisms or the regulatory signal transduction mechanisms that are responsible for mediating ES cell differentiation into cardiomyocytes are not well understood. Overcoming this huge scientific challenge is absolutely necessary before the use of stem cell-derived cardiomyocytes to treat the damaged heart can become a reality. Therefore the aim of this thesis was to investigate the signal transduction pathways that are involved in the differentiation of stem cells into cardiomyocytes. The first objective was the establishment and use of cardiomyocyte differentiation models using H9c2 cells and P19 stem cells to accomplish the specific objectives of the thesis. The specific objectives of the thesis were, the investigation of the roles of (i) nitric oxide (ii) protein kinase C (PKC), (iii) p38 mitogen-activated protein kinase (p38 MAPK) (vi) phosphoinositide 3-kinase (PI3K) and (vi) nuclear factor-kappa B (NF-kB) signalling pathways in the differentiation of stem cells to cardiomyocytes and, more importantly, to identify where possible any points of convergence and potential cross-talk between pathways that may be critical for differentiation to occur. P19 cells were routinely cultured in alpha minimal essential medium (α-MEM) supplemented with 100 units/ml penicillin /100 μg/ml streptomycin and 10% foetal bovine serum (FBS). P19 cell differentiation was initiated by culturing the cells in microbiological plates in medium containing 0.8 % DMSO to form embryoid bodies (EB). This was followed by transfer of EBs to cell culture grade dishes after four days. H9c2 cells were cultured in Dulbecco’s Modified Eagle’s medium (DMEM) supplemented with 10% FBS. Differentiation was initiated by incubating the cells in medium containing 1% FBS. In both models, when drugs were employed, they were added to cells for one hour prior to initiating differentiation. Cell monolayers were monitored daily over a period of 12 or 14 days. H9c2 cells were monitored for morphological changes and P19 cells were monitored for beating cardiomyocytes. Lysates were generated in parallel for western blot analysis of changes in cardiac myosin heavy chain (MHC), ventricular myosin chain light chain 1(MLC-1v) or troponin I (cTnI) using specific monoclonal antibodies. H9c2 cells cultured in 1% serum underwent differentiation as shown by the timedependent formation of myotubes, accompanied by a parallel increase in expression of both MHC and MLC-1v. These changes were however not apparent until 4 to 6 days after growth arrest and increased with time, reaching a peak at day 12 to 14. P19 stem cells cultured in DMSO containing medium differentiated as shown by the timedependent appearance of beating cardiomyocytes and this was accompanied by the expression of cTnI. The differentiation of both P19 stem cells and H9c2 into cardiomyocytes was blocked by the PI3K inhibitor LY294002, PKC inhibitor BIM-I and the p38 MAPK inhibitor SB2035800. However when LY294002, BIM-I or SB2035800 were added after the initiation of DMSO-induced P19 stem cell differentiation, each inhibitor failed to block the cell differentiation into beating cardiomyocytes. The NF-kB activation inhibitor, CAPE, blocked H9c2 cell differentiation into cardiomyocytes. Fast nitric oxide releasing donors (SIN-1 and NOC-5) markedly delayed the onset of differentiation of H9c2 cells into cardiomyocytes while slow nitric oxide releasing donors (SNAP and NOC-18) were less effective in delaying the onset of differentiation or long term differentiation of H9c2 cells into cardiomyocytes. Akt (protein kinase B) is the key downstream target of PI3K. Our cross-talk data also showed that PKC inhibition and p38 MAPK inhibition respectively enhanced and reduced the activation of Akt, as determined by the phosphorylation of Akt at serine residue 473. In conclusion, PKC, PI3K, p38 MAPK and NF-kB are relevant for the differentiation of stem cells into cardiomyocytes. Our data also show that the PKC, PI3K and p38 MAPK signalling pathways are activated as very early events during the differentiation of stem cells into cardiomyocytes. Our data also suggest that PKC may negatively regulate Akt activation while p38 MAPK inhibition inhibits Akt activation. Our fast NO releasing donor data suggest that nitric oxide may negatively regulate H9c2 cell differentiation.