Orientador: Mary Luci de Souza Queiroz / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-14T08:29:05Z (GMT). No. of bitstreams: 1 Torello_CristianeOkuda.pdf: 8596128 bytes, checksum: e07457446c814c5f191e0c629491876d (MD5) Previous issue date: 2009 / Resumo: Neste trabalho, investigamos os efeitos do extrato padronizado de Rhodiola rosea L. (ERR) sobre a resposta imunohematopoética de camundongos infectados com Listeria monocytogenes. Os resultados demonstram que o ERR aumenta a resistência dos animais frente uma dose letal de Listeria quando administrado profilaticamente nas doses de 100 e 250 mg/kg por sete dias consecutivos anteriores à inoculação. Paralelamente, reversão da mielossupressão induzida pela infecção, concomitante ao aumento na atividade de células natural killers (NK) e na produção das citocinas TNF-a, IFN-? e fatores estimuladores de colônias foram observados. Os resultados obtidos demonstram que o ERR compartilha da habilidade de regular positivamente os desequilíbrios hematopoiéticos e imunológicos envolvidos nos estágios iniciais da infecção com L. monocytogenes. Estes efeitos podem ser atribuídos à recuperação no equilíbrio da resposta hematopoiética através da produção de IL-1a e IL-6 pelas células estromais no microambiente medular e também da produção de fatores estimuladores de colônias a partir das 24 horas de infecção, promovendo aumento no número de progenitores de macrófagos e granulócitos na medula óssea. Além disso, a eficácia do ERR também depende do aumento na produção das citocinas TNF-a e IFN-?, do aumento na atividade funcional das células NK e polarização da resposta celular para Th1. Juntos, estes efeitos contribuem para o aumento na resistência a L. monocytogenes. / Abstract: In this work, we have investigated the effects of Rhodiola rosea L. extract (ERR) in Listeria monocytogenes infected mice. Our results demonstrated that ERR protects mice from a lethal dose of L. monocytogenes, when administered prophylactically at 100 and 250 mg/kg, for seven consecutive days prior to the infection. In addition, prevention of myelosuppression induced by infection, concomitant to increasing natural killers (NK) cells activity and production of TNF-a, IFN-? and colony-stimulating factors were observed. The results showed that ERR share the ability of regulating positively the hematopoietic and immunological unbalance involved in the initial stages of infection with this pathogen. These effects could be attributed to recovering of the hematopoietic response through the production of IL-1a and IL-6 by stromal cells in the bone marrow microenvironment and the production of colony-stimulating factors at 24 hours of infection, promoting an increase in the number of granulocytes and macrophages progenitors in the bone marrow microenvironment. Moreover, the efficacy of ERR depends on high levels of TNF-a and IFN- ?, increased NK cells activity and polarization to Th1 response. Together, these effects contribute to increasing resistance to L. monocytogenes. / Universidade Estadual de Campi / Farmacologia / Doutor em Farmacologia

INTRODUÇÃO: As células-tronco mesenquimais são capazes de regenerar diferentes tipos de tecidos, no entanto, a maioria dos métodos para sua obtenção são invasivos. Recentemente, foi descoberta a existência destas células no sangue menstrual. OBJETIVO: Padronizar as técnicas de coleta e transporte do fluido menstrual, bem como a caracterização, isolamento, expansão e criopreservação de células-tronco do fluido menstrual e avaliar a disponibilidade de células tronco mesenquimais no fluido menstrual. MÉTODOS: No período de agosto de 2011 a março de 2012 foram selecionadas 20 voluntárias com ciclo menstrual regular, sem doença ginecológica. O fluido menstrual foi coletado no dia de maior fluxo e submetido a imunofenotipagem e cultivo celular. Foram realizadas duas passagens em meio de cultura até atingir semi-confluência das células-tronco, as quais foram, em seguida, criopreservadas. RESULTADOS: Os parâmetros analisados apresentaram os seguintes valores médios: volume de fluido menstrual 6,90±5,60mL; tempo de transporte 17,20±5,50h; número de células totais 3,95 x106±3,88 x106 com 76,05%±24,57 de células viáveis. Após a cultura, as células mesenquimais aumentaram de 0,14%±0,26 para 96,19%±2,14. Na primeira passagem de cultura, após 15 a 21 dias, as colônias formaram grupos que atingiram a confluência, que a partir da segunda passagem ocorreu em cerca de 3 dias. As células-tronco mesenquimais criopreservadas eram viáveis. CONCLUSÃO: As células-tronco do fluido menstrual podem ser obtidas sem métodos invasivos. O fluido menstrual pode ser transportado em condições ideais de temperatura até 24 horas após a coleta. As células tronco mesenquimais podem ser caracterizadas por imunofenotipagem, isoladas, cultivadas e expandidas e, em seguida, criopreservadas. O fluido menstrual contém células tronco mesenquimais viáveis e apropriadas para cultivo / INTRODUCTION: Mesenchymal stem cells may renovate different tissues, but techniques to obtain these cells are invasive. Recently, those cells were detected in menstrual blood. OBJECTIVE: Patterning techniques of collection, transportation, characterization, isolation, expansion and cryopreservation of stem cells in menstrual fluid. METHODS: From August 2011 to March 2012 twenty volunteers were selected with regular menstrual cycle without gynecological diseases. They collected menstrual fluid on the most intense flux day to analysis by immunophenotyping and cellular culture. Culture was made in 2 stages until reached semi-confluence of stem cells and these cells were cryopreserved. RESULTS: Average of menstrual fluid volume was 6,90±5,60mL, transportation time was 17,20±5,50h, and total number of cells was 3,95 x106±3,88 x106 witch 76,05%±24,57 were viables. After culture, mesenchymal stem cells increased from 0,14%±0,26 to 96,19%±2,14. After 15 to 21 days of culture in first passage, colonies formed clusters that reached confluence. In second passage, it happens after 3 days of culture and stem cells were cryopreserved. CONCLUSION: Stem cells of menstrual fluid may be easily obtained without invasive methods. Menstrual fluid can be transported in good conditions of temperature up to 24 hours of collection. Mesenchymal stem cells of menstrual fluid may be characterized by immunophenotyping, as well as it is possible to isolated, cultivate and cryopreserved them. Menstrual fluid has viable and proper for culture mesenchymal stem cells

Orientador: Sara Teresinha Olalla Saad / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-18T22:22:55Z (GMT). No. of bitstreams: 1 Baratti_MarianaOzello_D.pdf: 9890862 bytes, checksum: f7eb8503519cc264f616a79dc48baf4f (MD5) Previous issue date: 2011 / Resumo: As síndromes mielodisplásicas (SMDs) constituem um grupo heterogêneo de desordens hematopoéticas, caracterizadas por exibirem hematopoese ineficaz com evidências de displasia da medula óssea resultando em citopenias no sangue periférico. Tecnologia de microarranjo tem permitido o refinado mapeamento da atividade transcricional do genoma humano. RNAs não codificadores (ncRNAs) transcritos de regiões intrônicas de genes conhecidos estão envolvidos em vários processos relacionados com controle transcricional e pós-transcricional da expressão gênica, interações com cromatinas, modificação de histonas e também estão se tornando evidentes em vários tipos de cânceres. Caracterização de ncRNAs em células progenitoras e células estromais de pacientes com SMD representa uma estratégia aparentemente importante para o entendimento da regulação gênica nesta doença. Neste estudo, o perfil de expressão gênica de células CD34+ e estromais de pacientes com SMD do subgrupo anemia refratária com sideroblastos em anel (ARSA) foi comparado com o de indivíduos saudáveis, usando oligoarranjos de 44 kilobases contendo íntrons e éxons, o qual incluiu sequências para genes codificadores, RNAs sense e antisense totalmente e parcialmente intrônicos. Em células CD34+ de pacientes com SMD-ARSA, 216 genes foram diferencialmente expressos (q-value ? 0,01) em comparação com indivíduos saudáveis, dos quais 65 (30%) eram transcritos não codificadores. O gene DMT1, um transportador de ferro, foi encontrado hiperexpresso em células CD34+ de SMD-ARSA. Em medula óssea total de 34 pacientes, a expressão foi mais evidente no subgrupo de pacientes com SMD de baixo risco/INT-1. Ensaios de imuno-histoquímica corroboram os dados encontrados na análise de expressão gênica e demonstram que DMT1 se encontra mais expresso nas células eritroblásticas. A hiperexpressão de DMT1 pode estar relacionada com o homeostase do ferro anormal nas SMDs. Em células estromais de SMD-ARSA, 12 genes foram diferencialmente expressos (q-value ? 0,05) em comparação com indivíduos saudáveis, dos quais 3 (25%) eram transcritos não codificadores. O gene SEMA3A, um membro secretado da família das semaforinas, foi encontrado hiperexpresso em células estromais de SMD-ARSA e na medula óssea total de 34 pacientes; sua hiperexpressão foi mais evidente em pacientes com SMD de alto risco/INT-2 e em pacientes com leucemia mieloide aguda (n=19). Ensaios funcionais demonstraram que SEMA3A está envolvido com aumento da adesão, diminuição da diferenciação e apoptose de células leucêmicas cocultivadas com células estromais HS27 hiperexpressando SEMA3A e age de maneira parácrina sobre as células precursoras. Pela primeira vez, o perfil diferencial de ncRNA em células CD34+ e células estromais entre SMD-ARSA e indivíduos saudáveis foi demonstrado, sugerindo que ncRNA pode ter um importante papel durante o desenvolvimento das síndromes mielodisplásicas / Abstract: Myelodysplastic syndromes (MDS) are a group heterogeneous of hematological disorders characterized by ineffective hematopoiesis with morphological evidence of marrow cell dysplasia resulting in peripheral blood cytopenia. Microarray technology has permitted a refined high-throughput mapping of the transcriptional activity in the human genome. Noncoding-RNAs (ncRNAs) transcribed from intronic regions of genes are involved in a number of processes related to post-transcriptional control of gene expression, and chromatins interaction, and histone modification and they are becoming evident in several cancers. Characterization of ncRNAs in progenitor cells and stromal cells of MDS patients could be strategic for understanding gene expression regulation in this disease. In this study, gene expression profiles of CD34+ and stromal cells of MDS patients with refractory anemia with ringed sideroblasts (RARS) subgroup were compared those of healthy individuals, using 44 kilobases combined introns and exons oligoarrays, which included probes for protein-coding genes, for sense and antisense strands of totally and partially intronic noncoding RNAs. In CD34+ cells of MDS-RARS patients, 216 genes were significantly differentially expressed (q-value ? 0.01) in comparison to healthy individuals, of which 65 (30%) were noncoding transcripts. The DMT1 gene, an iron-transporter, was found up-regulated in CD34+ cells of MDS-RARS. In the total bone marrow of 34 patients, the expression of DMT1 was more evident in the subgroup of low risk/INT-1 MDS patients. The immunohistochemistry assay confirms the data obtained in the gene expression assay and show that DMT1 is more expressed in erythroid cells. The higher expression of DMT1 can be related with abnormal iron homeostasis in MDS. In stromal cells of MDS-RARS, 12 genes were significantly differentially expressed (q-value ? 0.05) in comparison to healthy individuals, of which 3 (25%) were noncoding transcripts. The SEMA3A gene, a secreted member of the semaphorins family, was found up-regulated in stromal cells of MDS-RARS and in the total bone marrow of 34 patients; further, the higher expression was more evident in high risk/ INT-2 subgroup of MDS patients and acute myeloid leukemia patients (n = 19). Functional assays demonstrated that SEMA3A is related to adhesion increase, differentiation decrease, and apoptosis of leukemia cells cocultivated with HS27 stromal cells higher expressing SEMA3A, also acting in a paracrine fashion in the precursors cells. These results demonstrated, for the first time, in CD34+ cells and stromal cells the differential ncRNA expression profile between MDSRARS and healthy individuals, suggesting that ncRNAs may play an important role during the development of myelodysplastic syndromes / Doutorado / Medicina Experimental / Doutor em Fisiopatologia Medica

Le tissu osseux a la capacité de se régénérer suite à une fracture. Cependant, des consolidations incomplètes concernent aujourd’hui environ un million de personnes par an. L’approche d’ingénierie tissulaire associant des cellules stromales mésenchymateuses (CSM) à des biomatériaux émerge comme une stratégie prometteuse pour réparer ces défauts. Par ailleurs, l’efficacité de la régénération osseuse semble varier en fonction du donneur mais aussi du support associé. L’objectif de mon travail de thèse a été de comprendre les mécanismes à l’origine de ces variabilités. Pour cela, nous nous sommes intéressés à deux mécanismes : (i) l’impact des biomatériaux sur le devenir et les fonctions des CSM et (ii) l’impact de l’hétérogénéité inter-donneur des CSM sur les mécanismes moléculaires in vitro et in vivo, à l’origine des différences du potentiel ostéoformateur de ces cellules.Dans un premier temps, deux types de biomatériaux largement utilisés en clinique ont été comparés dans un modèle murin de greffe ectopique : une céramique biphasique d’hydroxyapatite/béta-tricalcium-phosphate (HA/bTCP) et une matrice osseuse humaine gamma-irradiée (Tutoplast® process Bone [TPB]). Nos résultats ont montré une meilleure formation osseuse lorsque les CSM sont combinées au TPB par rapport au HA/bTCP. Ceci est associé à une meilleure adhésion des CSM in vitro et in vivo ainsi qu’à une différentiation ostéoblastique supérieure sur le TPB. La contribution directe des CSM à former l’os est associée à un effet paracrine sur la chémoattraction et/ou la différentiation ostéogénique des cellules de l’hôte. Cet effet est indépendant des chimiokines PDGF et SDF-1 mais semble être régulé par la voie d’IGF-1. Un autre effet paracrine des CSM est observé sur l’activité ostéoclastique, qui est plus importante sur la céramique HA/bTCP et qui semble être régulée par le facteur RANKL. L’augmentation de l’activité ostéoclastique pourrait être à l’origine d’un déséquilibre de la balance résorption/formation osseuse sur le HA/bTCP.Ainsi, nos résultats montrent que le support impacte la persistance des CSM au niveau du site de la greffe ainsi que leur rôles directs et paracrines, l’ensemble étant à l’origine d’une variabilité de la formation osseuse.Cette formation osseuse a été observée avec seulement 70% des donneurs de CSM. Nous avons donc décidé dans la deuxième partie de ce projet d’évaluer les différences entre ces deux groupes de donneurs. In vitro aucune différence de prolifération, de différentiation ou de phénotypie des CSM n’a été observée. De plus, les analyses transcriptomique et sécrétomique réalisées in vitro n’ont montré aucune variabilité entre les deux groupes. In vivo, la persistance des CSM sur le site de la greffe est donneur dépendante et n’est pas liée à un défaut de vascularisation ou à une mort cellulaire par apoptose augmentée. Par ailleurs, nos résultats soutiennent l’existence d’une corrélation entre la formation osseuse et la capacité des CSM greffées à adhérer au support, survivre ainsi qu’à participer à la formation osseuse via une action directe et un effet paracrine.En conclusion, ce travail montre que l’efficacité de la formation osseuse dépend du devenir et des fonctions des CSM greffées. L’origine (donneur) ainsi que le microenvironnement (support associé) impactent l’adhésion, la survie et les mécanismes d’action de ces cellules au cours de la régénération osseuse. De plus, nous avons constaté que le potentiel ostéogénique des CSM est dû à leur participation directe à former l’os qui est synergique à un effet paracrine de chémoattraction et/ou de différentiation ostéogénique des cellules de l’hôte. / Despite bone capacity to regenerate after injury, incomplete consolidation concerns 1 million persons per year. Bone tissue engineering involving human bone marrow mesenchymal stromal cells (hBMSCs) loaded on biomaterials emerges as a new strategy to repair large bone defects. Nevertheless, efficacy of bone regeneration seems variable depending on the donor as well as on the associated scaffold. The aim of my PhD work was to understand mechanisms responsible for these variabilities. To this end, we focused on two objectives: (i) the impact of biomaterials on hBMSCs behavior and (ii) the impact of hBMSCs heterogeneities on molecular mechanisms in vitro and in vivo, resulting in variable bone-forming potential of these cells.First, two scaffolds widely used clinically were compared in an ectopic mouse model: the synthetic hydroxyapatite/beta-tricalcium-phosphate bioceramic (HA/βTCP) and the gamma-irradiated-processed human bone allograft (Tutoplast® Process Bone [TPB]). Our results showed that bone formation is higher when hBMSCs are loaded on TPB compared to HA/bTCP. This was correlated to a better hBMSCs adhesion in vitro as well as in vivo and to their higher osteoblastic differentiation on TPB. The direct participation of hBMSCs to form bone was associated to a paracrine effect of hBMSCs by inducing host cell chemoattraction and/or osteogenic differentiation, mediated probably by the IGF-1 pathway but independently from PDGF or SDF-1. Another paracrine effect was also observed on osteoclastic activity which was more important on HA/bTCP and could be RANKL dependent. This may impact the bone resorption/formation balance. Taken together, our results show that the associated scaffold impact MSCs persistence on the graft site, as well as their direct and paracrine effects leading to a variability in new bone amount.As bone formation was observed with only 70% of our donors, we then evaluated differences between the two groups. In vitro, no differences in cell proliferation, differentiation or phenotype were detected. Furthermore, transcriptomic and secretomic analysis in vitro did not identify any variability. The assessment of cell behavior in vivo showed that persistence of grafted cells was donor dependent and was not linked to a vascularization failure or a higher apoptosis. However, our results highlighted a correlation between bone formation and the ability of hBMSCs to attach and survive on the biomaterial as well as to contribute to bone formation by direct and paracrine effects.In conclusion, this work show that the efficacy of bone formation depend on the behavior of grafted hBMSCs. The origin (donor) and the microenvironment (associated scaffold) will impact their adhesion, survival and mechanisms of action during bone regeneration. Moreover, we identified that the osteogenic potential of hBMSCs act through a direct contribution that is synergic to a paracrine effect for host cell chemoattraction and differentiation.

Respiratory syncytial virus (RSV) is the most common cause of acute lower respiratory tract infection in young children worldwide, accounting for an estimated 33.8 million cases of respiratory disease, over 3 million of which require hospitalization, and between 66,000 and 199,000 deaths in this susceptible population. Additionally, severe RSV infection early in life is associated with an increased risk of wheeze and other airway disorders later in life. Despite this, there is currently no vaccine or economically reasonable prophylactic regimen to prevent infection. While disease is typically more severe in infancy RSV can infect throughout the lifespan repeatedly as the body does not develop protective immunity during primary or subsequent infection. The mechanisms behind this incomplete immunity are unclear. RSV has been reported to infect numerous extra-epithelial cell types. Interestingly, viral infection in human mesenchymal stem cells (MSCs) has been reported, but the consequences are poorly understood. MSCs are an immune regulatory cell population present in nearly every organ including the nasal mucosa and the lung. They play a role in regulating immune responses and mediating tissue repair. In the following studies we sought to determine whether RSV infection of MSCs enhances their immune regulatory functions and contributes to RSV-associated lung disease. RSV was shown to replicate in human MSCs by fluorescence microscopy, plaque assay, and expression of RSV transcripts. RSV-infected MSCs showed differentially altered expression of cytokines and chemokines such as IL-1β, IL-6, IL-8 and SDF-1 compared to normal human bronchial epithelial cells. Notably, RSV-infected MSCs exhibited significantly increased expression of IFN-β (~100-fold) and indoleamine-2,3-dioxygenase (IDO) (~70-fold) compared with mock-infected MSCs. IDO was identified in cytosolic protein of infected cells by Western blots and enzymatic activity was detected by tryptophan catabolism assay. Treatment of PBMCs with culture supernatants from RSV-infected MSCs reduced their proliferation in a dose dependent manner. This effect on PBMC activation was reversed by treatment of MSCs with the IDO inhibitors 1-methyltryptophan and vitamin K3 during RSV infection. We also demonstrated the pathway leading to IDO expression in RSV infected MSCs. Neutralizing IFN-β prevented IDO expression and activity indicating its role as a viral response factor perhaps “high jacked” by the virus in immune escape. Treatment of MSCs with an endosomal TLR, but not a RIG-I, inhibitor prevented IFN-β and IDO expression. Additionally, TLR3/dsRNA complex inhibitor was able to block IFN-β stimulation, while a TLR7/8/9 inhibitory ODN did not, suggesting that endosomal TLR3 detection of RSV dsRNA was leading to IFN-β and IDO expression. Together, these findings indicate that RSV infection of MSCs triggers their immune regulatory function via TLR3 recognition of dsRNA, upregulating IFN-β expression and IDO activity, ultimately affecting immune cell proliferation. This finding may account for the lack of protective RSV immunity and consequent repeated infections throughout one's lifetime.

Grâce à leurs propriétés de différenciation, les cellules stromales mésenchymateuses (CSM) constituent aujourd’hui un outil en médecine régénérative. La moelle osseuse reste une des plus utilisées. Une diminution de la capacité de prolifération et de différenciation des CSM-MO, au cours des passages, a été montrée. En parallèle, certaines études montrent que l'impact de l'âge du donneur sur les propriétés de CSM-MO reste encore controversé. Le but de notre étude était de mieux comprendre l'effet de l'âge du donneur mais aussi des passages en culture sur la capacité de prolifération et de différenciation des CSM de moelle osseuse. Les échantillons ont été séparés en 4 groupes en fonction de l’âge des donneurs (<20 ans; 20-40 ans; 40-60 ans; >60 ans) et les analyses ont été réalisés lors de la culture de cellules pendant 5 passages. Les résultats obtenus montrent que la capacité de prolifération de CSM-MO obtenues à partir de donneurs jeunes est supérieure à celle de cellules des donneurs âgés. De plus, cette capacité de prolifération diminue en fonction des passages en culture. En parallèle, la capacité des cellules à former des colonies, mesurée par le test CFU-F, diminue légèrement en fonction de l’âge des donneurs mais de façon importante en fonction du passage. Enfin, la capacité de différenciation des CSM-MO vers les trois types cellulaires étudiés, diminue en fonction des passages de cellules mais également en fonction de l’âge des donneurs. Notre étude montre que les propriétés des CSM issues de moelle osseuse sont modifiées lors de l’amplification in vitro mais aussi en fonction de l’âge des donneurs / Today with their properties of differentiation into specific cells types, mesenchymal stromal cells (MSC) can be used in regenerative medicine. Bone marrow (BM) is the better characterized one. The researchers have proven that with increasing passage number in culture the proliferation and differentiation potential of MSC decrease. In parallel many researchers have showed the impact of donor age on MSC properties remains controversial. The aim of our study was to better understand the effect of donor age but also culture passages on the proliferation and differentiation ability of bone marrow mesenchymal stromal cells. The samples were separated into 4 groups depending on the donor age (<20 years; 20-40 years; 40-60 years; > 60 years) and The samples were cultured for 5 passages. The results obtained show that the MSC proliferative capacity obtained from young donors is greater than that of cells from older donors. In addition, the proliferative capacity decreases with increasing passage number in culture. In parallel, the ability of colony-forming unit-fibroblast, measured by the CFU-F assay, decreases slightly depending on the age of the donors but significantly depending on the passage. Finally, the MSC differentiation ability decreases according to the passage of the cells but also depending on the donor age. Our study shows that the properties of bone marrow derived MSC are modified not only during amplification in vitro but also in terms of donor age

Diese Arbeit verdeutlicht die Wirkung von Chondroitinsulfat auf die Synthese von Prostaglandin E2 in humanen mesenchymalen Stromazellen in Abhängigkeit ihres Sulfatierungsgrades. MSC zeichnen sich durch ihre antiinflammatorischen Eigenschaften aus und haben damit einen modulierenden Effekt auf Wundheilungsprozesse. Als Vorläuferzellen von Osteoblasten sind sie direkt an der Knochenneubildung beteiligt. Eine persistierende Entzündung hat eine kontinuierliche Freisetzung von Zytokinen, wie IL-1 zur Folge. Es konnte gezeigt werden, dass IL-1 in hMSC zu einer Freisetzung von PGE2 führt. Unter kurzzeitiger Wirkung stimuliert PGE2 die Knochenneubildung. Eine langanhaltende Präsenz leitet dagegen die Bildung des Faktors RANKL, einen die Osteoklastogenese stimulierenden Faktor, ein. Seit langem ist der positive Effekt von Chondroitinsulfat in chronischen Entzündungsprozessen, wie Rheumatoider Arthritis, bekannt. Zudem werden sie in aktuellen Studien als Beschichtungsbestandteile von Knochenimplantaten verwendet. Sie führten hier zu einer besseren Bioinduktivität und Biokonduktivität. Bisher ist dennoch der molekulare Wirkmechanismus nicht genau beschrieben. Die Schwierigkeit besteht darin, dass die molekularen Signalkaskaden für die einzelnen Kulturmoldelle Unterschiede aufweisen und kein ubiquitärer Mechanismus dargestellt wird. In hMSC führte die Stimulation mit IL-1 unter vorheriger Zugabe von Chondroitinsulfat zu einer Reduktion der PGE2 Freisetzung. Der Effekt des hochsulfatierten sCS3 war gegenüber dem nativen C4S verstärkt. Die reduzierende Wirkung von C4S setzte verzögert ein. Es ist bereits bekannt, dass die negative Ladung der CS zu einer Bindung von Zytokinen führt. Dadurch wird eventuell die Konzentration der Zytokine, wie IL-1 im Bereich der Zellrezeptoren erniedrigt und führt zu einer verringerten Stimulation der Zelle. Denkbar ist auch die Beeinflussung der intrazellulären Signaltransduktionskaskade durch die Bindung der CS an einen speziellen, bisher unbekannten, Membranrezeptor. Die entscheidenden Enzyme der PGE2 Synthese sind die Cyclooxygenase-2 (Cox-2) und die mikrosomale Prostaglandin E Synthase 1 (mPGES1). Die mRNA beider Enzyme war unabhängig vom Sulfatierungsgrad der CS reduziert. Dieser Effekt konnte auf Protein-ebene nicht belegt werden. Die produzierte Proteinmenge an mPGES1 wird durch IL-1 induziert, bleibt aber auch durch Zugabe von CS unverändert. Somit kann von einer erhöhten Translationseffizient und mRNA Stabilität der mPGES1 RNA ausgegangen werden. MAPK Kinasen sind entscheidende Schnittstellen bei der Regulation der mRNA Stabilität als auch der Aktivität von Transkriptionsfaktoren. In dieser Studie konnte die MAPK p38 als entscheidendes Enzym bei der Wirkung von CS auf die PGE2 Synthese ermittelt werden. Dabei führten sowohl das natürliche C4S als auch das hochsulfatierte sCS3 zu einer verringerten Aktivierung. Der Transkriptionsfaktor NfkB ist einer von mehreren, die an den Promotorbereichen der beiden induzierbaren PGE2 Enzyme, Cox-2 und mPGES1, binden. Es ist anzunehmen, dass die hier aufgezeigte verringerte Aktivität von NfkB als auch die verhinderte Translokation in den Zellkern eine reduzierte Transkription der jeweiligen mRNA bedingten. Abhängig vom untersuchten Modell und den verwendeten Kulturbedingungen können diese Prozesse moduliert sein. Die Erkenntnisse dieser experimentellen Arbeit liefern einen weiteren wichtigen Baustein zum Verständnis der molekularbiologischen Abläufe während entzündlicher Prozesse. Die Verwendung von Chondroitinsulfat, insbesondere hochsulfatiertes CS, in Kombination mit hMSC kann gezielt zu einer Verringerung der Entzündungsreaktion während der Implantateinheilung führen. Die durch PGE2 hervorgerufenen Symptome, wie erhöhte Gefäßpermeabilität, Schwellung und verstärktes Schmerzempfinden begründen diese positiven Effekte.

Au début de ma thèse, je me suis intéressé aux processus qui sous-tendent la communication cellulaire et plus spécifiquement les interactions cellule-cellule. Pourquoi une cellule établit-elle un contact spécifique avec une autre cellule ? Comment les cellules répondent-elles à cette interaction et quels en sont les effets ? J'ai utilisé comme modèle d'étude l'interaction entre les cellules souches/stromales mésenchymateuses (CSM) et des lignées de cancer du sein. L'objectif de mon travail a été d'analyser les mécanismes de ces interactions entre CSM et cellules cancéreuses et d'en évaluer les effets sur les fonctions des cellules cancéreuses. En effet, des mécanismes de recrutement des CSM aux sites tumoraux ont été décrits avec des effets sur la progression tumorale, ce qui ouvre par ailleurs des perspectives pour de nouvelles approches thérapeutiques. J'ai tout d'abord développé un système expérimental de microscopie confocale en temps réel pour observer le type d'interaction qui est produit entre les CSM humaines et les cellules de carcinomes mammaires MDA-MB-231 et MCF7. J'ai constaté la formation dynamique de structures tubulaires entre les deux types cellulaires et, de façon surprenante, le passage des mitochondries des CSM vers les cellules cancéreuses. En un deuxième temps, j'ai utilisé un système d'invasion dans une matrice 3D de collagène, que nous avons adapté à la coculture, afin d'observer les effets de l'interaction des MDA-MB-231 avec les CSM. En accord avec la littérature, nous avons constaté une augmentation du pouvoir invasif des cellules cancéreuses, effet qui pouvait être lié au transfert des mitochondries provenant des CSM. Pour répondre à cette question, j'ai mis au point un protocole pour transférer spécifiquement des mitochondries, isolées à partir de cellules, vers d'autres cellules. Ce protocole, exploité dans ce manuscrit pour le transfert de mitochondries de CSM vers les cellules cancéreuses MDA-MB-231, peut être transposé à d'autres types cellulaires et fait l'objet d'une demande de brevet. Nos données indiquent que l'acquisition de mitochondries de CSM par les cellules cancéreuses modifie leurs propriétés fonctionnelles et augmente leur capacité de prolifération et d'invasion. Concernant leur activité métabolique, on observe une augmentation de leur respiration mitochondriale et de leur production d'ATP. Nos données préliminaires suggèrent aussi une augmentation de l'expression transcriptionnelle d'enzymes impliquées dans la synthèse des lipides et l'oxydation des acides gras. Ces données, générées grâce au protocole de transfert artificiel de mitochondries mis au point, montrent pour la première fois que les mitochondries des CSM peuvent majorer certaines propriétés cellulaires liées à la progression tumorale, comme la prolifération et l'invasion, et contribuer à une reprogrammation métabolique des cellules cancéreuses. Elles s'intègrent au rôle proposé par la communauté scientifique pour les CSM dans le microenvironnement tumoral. La technique de transfert artificiel de mitochondries nous permettra de répondre à d'autres questions restées ouvertes, comme le rôle possible des mitochondries des CSM dans les résistances développées par les tumeurs vis-à-vis des agents anti-cancéreux. Le protocole de transfert de mitochondries développé au laboratoire constitue une technique de choix et offre de nombreux avantages comparativement à d'autres techniques comme la micro-injection et la génération des hybrides cytoplasmiques. Sa mise en œuvre est en effet simple et reproductible et permet de traiter une grande quantité de cellules. Cette méthode permet d'envisager de nombreuses perspectives et applications dans le domaine de la reprogrammation métabolique, comme par exemple de restaurer les capacités d'une cellule dysfonctionnelle par le transfert de mitochondries issues d'une cellule saine et « métaboliquement active ». / At the beginning of my thesis, I was interested in the process involved in cell communication, more specifically in cell-to-cell interactions. Why does a cell specifically establish contacts with another one, how do cells respond to these interactions and what are the effects? As a model to answer these questions, I studied the interactions between MSCs and two breast cancer cell lines. The study of the communications between MSCs and tumor cells is an alternative to explore and understand tumor progression. MSC recruitment to the tumor is shown to favor the progression of the disease. The mechanisms of this dialogue are multiple and are the object of a great number of studies that aim at finding new therapeutic approaches. The objective of this work was to analyze the interactions between MSCs and cancer cells and evaluate the potential effects of this communication in tumor progression. First, I developed an experimental system of real time confocal microscopy in order to observe the interaction produced between MSCs and the breast carcinoma MDA-MB-231 and MCF-7 cells. I noticed the dynamic formation of tubular structures between the two different cell types and, surprisingly, the passage of mitochondria from MSCs to the cancer cells. Second, we used a 3D system of cell invasion in a collagen matrix, which we adapted for the coculture, in order to observe the effects of the interactions between the MDA-MB-231 and MSCs. In agreement with the literature, we observed an increase in the migratory potential of the cancer cells, an effect that could be linked to the transfer of mitochondria from MSCs to the cancer cells. To answer this question, I set up a protocol to specifically transfer to the cancer cells mitochondria isolated from the MSCs and test directly the functional consequences for the cancer cells. This protocol can be used to transfer mitochondria, not only from MSCs but also from other cells. This method is currently submitted to a patent process. Our results show that the transfer of MSC mitochondria to the cancer cells modifies cancer cells functional properties and increase their invasive and proliferative capacities. Concerning the metabolic activity, we noticed an increase in mitochondrial respiration and ATP production. We also observed an increase in the transcription level of enzymes related to the lipid synthesis and fatty acid oxidation. The results generated with this new protocol of mitochondria transfer show, for the first time, that mitochondria originating from MSCs can improve cellular capacities linked to the tumor progression. The role proposed by the scientific community for the interactions of MSCs with the tumor cells fits with the data generated in our work. Several questions remain open. In particular, could the transfer of mitochondria from MSCs to the cancer cells contribute to the acquisition of resistance to anti-cancer agents observed in patients? The protocol of transfer of mitochondria that we developed in the laboratory is a technique of choice and offers many advantages over other techniques such as microinjection and cytoplasmic hybrids; its implementation is simple and reproducible and can target large numbers of cells. This method opens numerous perspectives and potential applications such as the study of metabolic reprogramming. Thus, we could consider restoring the activity of dysfunctional cells by transferring mitochondria from “metabolically active” or healthy cells. In the long term, one of the applications could be transferring healthy or genetically modified mitochondria to zygotes carrying mitochondrial DNA mutations, in order to treat pathologies like infertility, neuro-degenerative diseases, cancer and premature aging.

O sucesso no desenvolvimento de tumores não dependente somente de mutações, mas também é influenciado pelo microambiente do tumor; nele ocorre a interação entre as células tumorais e o estroma. Essa interação pode ser mediada por vesículas liberadas por essas células para o meio extracelular. Essas vesículas atuam na comunicação celular que pode influenciar a progressão tumoral. O objetivo deste estudo foi analisar as interações mediadas por vesículas entre células tumorais e fibroblastos normais. As células tumorais foram plaqueadas sobre a monocamada de fibroblastos e carregadas com diferentes corantes vitais. Nossos resultados evidenciaram a presença e a troca de vesículas entre as células em co-cultura. Vesículas isoladas mostraram tamanhos heterogêneos. Células tumorais possuem mais vesículas que as células normais. As vesículas são compostas pelas proteínas AHNAK e Anexinas. AHNAK foi detectada em vesículas trocadas e estava aumentada em tumores. AHNAK é molécula estrutural das vesículas extracelulares que pode influenciar a biologia dos tumores de mama. / The successful development of tumors is not only dependent on cell mutations, but also driven by the tissue microenvironment; relies on interaction of cells and their surrounding stroma. Some cell types release vesicular structures into the extracellular space that would be involved in cellular communication and tumor progression. The aim of this study was to analyze vesicle-mediated interactions between tumor cells and normal fibroblasts. Tumor cells were plated above fibroblasts monolayer and both loaded with different vital dyes. Our results evidenciated presence and exchange of vesicles between breast tumor cells and fibroblasts in co-culture. Vesicles isolated showed heterogeneous sizes. Tumor cell showed more vesicles than normal cells. These vesicles were composed of AHNAK and Annexins proteins. The protein AHNAK was detected in exchanged vesicles and was increased in tumors when compared to normal breast tissues. AHNAK could represent a vesicle structural molecule that would influence breast tumor biology.

Introduction It is well known that resident adipose stem/stromal cells (ASCs) are a heterogeneous population of multipotent cells characterized by (a) their ability to adhere to plastic; (b) immunophenotypic expression of certain cell surface markers, while lacking others; and (c) the capacity to differentiate into cells of mesodermal origin including osteocytes, chondrocytes and adipocytes. Adipose derived stromal cells offer great therapeutic potential in multiple medical fields, including, orthopedics, cardiology, oncology and degenerative diseases, to name a few. Combining different disciplines of medicine and engineering, organ and tissue repair can be achieved through tissue engineering and regenerative medicine. Adipose derived stromal cells (ASCs) can be utilized as biological vehicles for vector-based gene delivery systems, since they home to sites of inflammation and infection in vivo. In order to reach the long-term aim of clinical translation of cell-based therapy, preclinical safety and efficacy need to be shown in animal models. This has motivated the development of standardized isolation, characterization and differentiation operating procedures as well as an in vivo tracking system for ASCs and lentiviral vector transduction for a vector-based gene delivery system. Methodology Human ASCs were isolated from lipoaspirate, expanded in culture, immunophenotyped using flow cytometery and induced to differentiate into adipogenic, osteogenic and chondrogenic lineages. Tri-lineage differentiation was confirmed by microscopy. The ASCs were then transduced with green fluorescent protein (GFP)-expressing lentiviral vectors in vitro. The effect of the GFP lentiviral vector on ASCs was investigated by studying ASC immunophenotypic expression of surface markers as well as their capacity to differentiate into osteocytes, chondrocytes and adipocytes. Results The isolated and expanded cell population, from harvested lipoaspirate adhered to recommended ASC identity criteria. The heterogeneity of ASCs was confirmed by the presence of sub-populations. Transduction efficiency in ASC cultures of approximately 80% was observed after introducing a total of 300 μl of concentrated lentiviral vector suspension per 4.8 x 104 cells. No immunophenotypic differences were observed between GFP positive and GFP negative cultures. Flow cytometric analysis revealed a progressive increase in GFP expression following in vitro expansion of transduced ASCs. Both non-transduced and transduced cultures successfully differentiated into osteocytes, chondrocytes and adipocytes. Conclusion The isolated and expanded cell population conformed to the recommended characterization criteria. Heterogeneity was demonstrated with the identification of immunophenotypic sub-populations and semi-quantification of adipogenesis was performed. ASCs were efficiently transduced using the GFP lentiviral vectors produced in our facility. In addition, transduced ASCs maintained adherence to plastic, ASC immunophenotype and were able to differentiate successfully into cells of the three lineages of mesodermal origin. This optimized GFP-ASC transduction technique offers a feasible tracking system as well as a vector-based gene delivery system for future preclinical studies. / Dissertation (MSc)--University of Pretoria, 2015. / tm2015 / Immunology / MSc / Unrestricted