In several cases, current therapies available to treat a large number of musculoskeletal system diseases are unsatisfactory as they provide only temporary or partial restoration of the damaged or degenerated site. In an attempt to maintain a high standard of life quality and minimise the economic losses due to the treatments of these frequently occurring ailments and subsequent lost working days, alternative therapies are being explored. Contrary to the current treatments, tissue engineering aims to regenerate the impaired tissue rather than repair and alleviate the symptoms; thus offering a definitive solution. The annulus fibrosus (AF) of the intervertebral disc (IVD) is a musculoskeletal system component frequently subjected to degeneration and rupture, characterised by predominance of anisotropically arranged collagen fibres. In the present thesis, electrospinning technology is used to fabricate polycaprolactone (PCL) scaffolds intended to replicate the anisotropic structure of the AF.

Mesenchymal stem cells are the stem cells that replace the bone, fat and cartilage tissues of the human body. In addition, these cells can form muscles, ligaments and neurons. This wide multipotency has made mesenchymal stem cells of particular interest in the fields of tissue engineering and regenerative medicine. Furthermore, mesenchymal stem cells can modulate the immune system by reducing factors that increase inflammation and immune recognition. This immune recognition suppression has resulted in their application as part of bone marrow transplantation in the prevention of 'graft versus host‘ disease. There are hundreds of on-going clinical trials using these cells for the treatment of autoimmune diseases such as type I diabetes, arthritis and multiple sclerosis. The increasing importance of these cells has brought in to focus the culture methods used to for their expansion and manipulation. Currently, animal derived components are used as surfaces for their growth and as components in the culture media. This exposes these cells to animal pathogens and antigens that can be passed to the recipients of these cells. In the first part of this thesis, polymer microarrays were employed to identify alternatives to the biological surfaces currently used for mesenchymal stem cell culture. This platform allowed hundreds of polyacrylates/acrylamides and polyurethanes to be simultaneously scrutinised to identify surfaces that could support their growth and maintain their stem cell characteristics. Identified polymer surfaces were monitored in long-term culture (10 passages) and were shown to retain the cell phenotype and capacity to differentiate, thus providing chemically defined substrates for long-term mesenchymal stem cell culture. In the second part of this thesis, a 'smart‘ polymer microarray of hydrophilic cross-linked polymers (hydrogels) were used to remove another key biological component of culture, trypsin. These 'smart‘ hydrogels modulated their properties depending on the temperature. Hydrogels that could trigger mesenchymal stem cell release after a reduction in temperature were identified. A unique passaging system using a modest temperature reduction for 1h was developed as a passaging method. Cells were maintained and monitored for 10 passages using this novel enzyme free passaging method. Analysis of the mesenchymal stem cell phenotype and differentiation capacity revealed this method superior than conventional culturing methods. In the final part of this thesis, a 'knowledge-based‘ small molecule library was designed, which could potentially yield small molecules to manipulate/enhance the mesenchymal stem cell state without the use of biological components. The key protein pathways that control the stem cell state were examine with the bioinformatics tool GeneGo was used to identify compounds that affected these pathways, resulting in selection of 200 small molecules. The effect of the small molecules on the mesenchymal phenotype was examined and 5 small molecules were identified that enhanced the phenotype of these cells. The anti-inflammatory properties associated with the hit compounds led to the investigation of their effects on key surface proteins associated with the immune-modulatory state of the cells. In this preliminary study, two of the small molecules, estriol and spermine, increased the expression of a key mesenchymal stem cell marker STRO-1 and down regulated ICAM-1, a critical component of the immune modulation capacity of this cell type.

Objetivo: O objetivo do presente estudo foi avaliar morfologicamente os tecidos pulpar e periapical de molares de ratos com a polpa vital e expostos ao meio bucal durante o desenvolvimento radicular, além de detectar a localização do STRO-1 e do BMP4 nos mesmos. Métodos: Foram utilizados 24 ratos machos da linhagem Wistar com quatro semanas de idade. A fim de induzir a necrose, foi realizada a exposição pulpar dos primeiros molares inferiores esquerdos em condições não-assépticas e deixando a polpa exposta ao ambiente oral (grupo teste). Os molares inferiores do lado direito não sofreram intervenção e serviram como grupo controle. A eutanásia dos animais foi realizada nos tempos de 7, 10, 13 e 16 semanas de vida (o equivalente a 3, 6, 9 e 12 semanas após a intervenção). Após, as mandíbulas foram dissecadas e processadas para a análise histológica através de Hematoxilina-Eosina e Imunohistoquímica. Foram comparadas, entre os grupos, em cada um dos períodos, a reação inflamatória periapical, as características do tecido pulpar (células inflamatórias, vascularização, odontoblastos, degeneração, destruição tecidual), fechamento do forame e presença de reabsorções. Resultados: Todos os dentes do grupo teste apresentaram necrose pulpar e a interrupção do desenvolvimento radicular. Enquanto isso, os dentes do grupo controle apresentaram o desenvolvimento normal dos tecidos dentários. Quanto à imunohistoquímica, foi constatada a marcação pelo BMP-4 no tecido pulpar dos dentes do grupo controle. Não houve, no entanto, marcação nos dentes do grupo teste. Para o STRO-1, a marcação foi mais evidente na região dos vasos sanguíneos, tanto no grupo controle, quanto no grupo teste. Para nenhum dos anticorpos, foi constatada marcação na região da papila apical. Conclusão: No presente estudo, a técnica imunohistoquímica não foi suficiente para a avaliação da presença de células-tronco na região da papila de dentes com rizogênese incompleta e necrose pulpar. É possível que a presença de infecção e a reação inflamatória tenham bloqueado a expressão do STRO-1 e do BMP-4. / Objective: the aim of this study was to characterize the features of live and necrotic dental pulps of molar teeth in rats with developing roots, and to assess the expression of STRO-1 and BMP-4. Methods: twenty-four 4-month-old male Wistar rats were used. To induce necrosis, the pulps of the first lower left molars were exposed to the oral environment. The lower right molars served as the control non-operated group. Euthanasia of animals was carried out at 7, 10, 13 and 16 weeks and the jaws were dissected and processed for histological analysis by hematoxylin-eosin and immunohistochemistry. The periapical inflammatory reaction, the characteristics of the pulp tissue (inflammatory cells, vascularity, odontoblasts, degeneration, tissue destruction), closure of the foramen and presence of resorptions were described at each period. Results: all teeth from the test group presented pulp necrosis, occurring discontinuation of root development. Meanwhile, the teeth of the control group showed normal development of dental tissues. BMP-4-positive cells were detected in the pulp of teeth from the control group. However, there was no expression in teeth of the test group. For STRO-1, expression was more evident in the blood vessels, both for the control group and for the test group. Apical papilla evidenced no BMP-4 nor STRO-1 expression. Conclusion: Immunohistochemistry was not sufficient to evaluate the presence of stem cells in the apical papilla region of nonvital immature teeth. It is possible that the inflammatory process has blocked the expression of STRO-1 and BMP-4., Probably, infection has negatively modulated this expression.

Proposição: este estudo busca avaliar, por resultado histológico, e por imagem, o reparo ósseo baseado na aplicação de células-tronco mesenquimais derivadas do tecido adiposo (CTAD), através do preenchimento das cavidades cirúrgicas com bloco de cimento de α-fosfato tricálcico (α-CFtC) e esponja de gelatina absorvível (EGA). Metodologia: foram utilizados 32 ratos da espécie Rattus novergicus albinus, linhagem SHR, isogênicos, divididos em quatro grupos, com sete, 14, 30 e 60 dias de pós-operatório. Na diáfise óssea de cada fêmur direito, houve a confecção de duas cavidades críticas ósseas, sendo designadas: Controle 1 (C1) ou Teste 1 (T1), localizados na porção proximal ou superior do fêmur, e Controle 2 (C2) ou Teste 2 (T2), localizado na porção central do fêmur. No leito T1 foi implantado o bloco de α-CFtC, pré-incubado com células-troncos mesenquimais derivadas do tecido adiposo (CTAD), e em T2, fragmento de EGA associada, no transcirúrgico, às célulastronco (CTAD). No leito C1, foi implantado o bloco de α-CFtC, e no leito C2, fragmento de EGA. Os leitos C1 e C2 não receberam as células-tronco. Avaliou-se o reparo ósseo, comparativamente entre os grupos estudados, através de análise visual por escores de exames por imagem (Radiografia e Tomografia Computadorizada de Feixe Cônico - TCFC) e através de análise histomorfométrica dos cortes histológicos. Resultados: A análise visual por escores dos exames por imagem, não revelou diferença estatística significante na Radiografia, porém, nas TCFC, observou-se melhores escores para reparo ósseo nos Grupos Testes, que receberam as células-tronco. Aos sete e 60 dias pós-operatórios, observou-se que no Grupo Teste, que utilizou o bloco de α-CFtC, houve uma aceleração no processo de reparo ósseo, com maior neoformação óssea e maior preenchimento da cavidade. O mesmo observou-se na cavidade do Grupo Teste que continha o EGA com associação de células-tronco, aos 14 dias pós-operatórios. No Grupo Controle que recebeu o EGA, de 14 e 30 dias, observou-se intensa fibroplasia, o que não foi verificado nos demais grupos. Conclusões: a radiografia que utiliza filme dental não revelou diferença entre os grupo estudados, porém os resultados da análise por escores (TCFC) mostraram uma aceleração no processo de reparo ósseo nos grupos testes. A utilização de células-tronco, associadas aos biomateriais (α-CFtC e EGA), mostrou aceleração do processo de reparo ósseo, em ratos, quando comparadas às cavidades sem células. As cavidades preenchidas com EGA, que não receberam células-tronco, quando comparadas com as cavidades que receberam as CTAD, aos 14 e 30 dias, apresentaram intensa fibroplasia e conseqüente atraso na ossificação endóstea. / Aims: this research aims to describe, through a histological analysis and imaging study, the quality of bone healing under adipose mesenchymal stem cells application (CTAD), with α-CFtC implant and absorbable gelatin sponge (EGA). Methodology: were studied 32 strain rats Rattus novergicus albinus, SHR (spontaneously hypertensive rats), isogenics, divided into four groups: seven, 14, 30 and 60 postoperative days. In the right femoral diaphysis, two drilled cavities were created: Control 1 (C1) or Test 1 (T1), in the proximal portion of the femur, and Control 2 (C2) or Test 2 (T2), in the central portion of the femur. T1 was filled with α-CFtC block incubated with mesenchymal stem cells, and T2 was filled with EGA associated to the cells (CTAD). C1 was filled with α-CFtC block and C2 with EGA, both without cell engeneering. Results of bone repair were analysed by imaging study (X-Ray and TCFC) and histomorphometry. Results: The visual X-ray test does not show any statistical difference between experimental groups. However, visual TCFC test showed better results in Tests Groups. Seven and 60 days: Test Group – in T1 (α-CFtC) was observed bone healing acceleration, with a statistical difference between experimental groups. The same was observed in 14 days, in Test Group – T2 (EGA). Contrasting with this, the Groups with EGA (C2) - 14 and 30 postoperative days - showed intense fibroplasy. Conclusions: the X-ray does not show any statistical difference between experimental groups, but TCFC images showed bone healing acceleration in Tests Groups. The mesenchymal cell application, associated to biomaterials (α-CFtC and EGA) showed acceleration in the bone healing process, in rats, when compared with cavities from the Control Groups. The cavities C2 (EGA - without cell therapy), in 14 and 30 postoperative days, developed an intense fibroplasy and showed delay bone healing process.

O desenvolvimento e a progressão do câncer bucal envolvem processos complexos de múltiplas etapas levando a modificações fenotípicas nas células epiteliais, aumento da proliferação e invasão dos tecidos subjacentes. Diversos fatores vem sendo associados à carcinogênese, dentre eles os mecanismos epigenéticos como a acetilação de histonas, que promovem mudanças na expressão de genes independente de mutações. O objetivo do presente estudo observacional transversal foi analisar a relação entre acetilação da histona 3 (acetil Histona H3) com proliferação celular e transição epitélio-mesênquima na mucosa bucal normal (MBN), leucoplasias bucais (LB) e carcinomas espinocelulares (CEC) de boca, bem como correlacioná-los com dados clínico-demográficos, graduação histopatológica e o comportamento das lesões. Foram analisados 10 casos de mucosa bucal normal (MBN), 20 casos de LB e 75 casos de CEC de boca. Todos os casos foram submetidas a análise imunoistoquímica utilizando anticorpos anti-acetil Histona H3, Ki67, vimentina e TGF-β1. A imunomarcação da acetil histona H3 foi significativamente menor nos casos de CEC quando comparados a LB (p=0.03). Não foi encontrado diferença entre os casos de MBN e LB. Paralelamente, foi observado um aumento estatisticamente significativo na proliferação durante o processo de carcinogênese (p<0.00) e o mesmo foi observado quando avaliados os marcadores da transição epitélio-mesênquima, vimentina (p=0.03) e TGF-β1 (p<0.00). A análise da associação dos marcadores com fatores clínicos-demográficos não mostrou diferença significativa. Entretanto, maior média de acetil histona H3 foi associada ao bom prognóstico (p=0.01) e também, foi observado uma tendência de uma melhor taxa de sobrevida (p=0.06). Conclui-se que os CEC de boca são hipoacetilados, exibem maior perfil proliferativo e de transição epitélio-mesênquima. Além disso, a acetil histona H3 pode ser considerada um marcador prognostico nestas lesões. / The development and progression of oral cancer involve multi-step processes leading phenotypic changes in epithelial cells, proliferation increase and invasion of adjacent tissue. Several factors have been associated with carcinogenesis, including epigenetic mechanisms such as histone acetylation, which promote changes in the expression independent of gene mutations. The aim of the present study was to analyze the association of acetylation of histone 3 (acetyl-histone H3) with cell proliferation and epithelial-mesenchymal transition in oral leukoplakia (OL) and oral squamous cell carcinoma (OSCC) and correlate them with data clinic-demographic, histopathological grading and the behavior of these lesions. We analyzed 10 cases of normal oral mucosa (NOM), 20 cases of OL and 75 cases of OSCC. All samples were submitted to immunohistochemical analysis using anti-acetyl histone H3, Ki67, vimentin and TGF-β1. Acetyl-histone H3 labeling was significantly lower in cases of OSCC compared to LB (p=0.03). It was not found difference between NOM and OL. In parallel, the proliferation analysis revealed a gradual increase on Ki67 labeling (p<0.00) during oral carcinogenesis with highest value detected in OSCC Also, an increase on EMT markers, vimentin (p=0.03) and TGF-β1 (p<0.00) were noted. A higher mean acetyl-histone H3 was associated with good prognosis (p= 0.01) and similarly a tendency to improved survival rate was observed (p=0.06). As conclusion, OSCC are hypoacetylated, exhibit higher proliferative profile and epithelial-mesenchymal transition characteristics. Furthermore, acetyl histone H3 can be considered a prognostic marker in OSCC.

hCLCA2 and hCLCA4 are chloride channel regulators that are expressed in normal breast epithelial cells and frequently downregulated in breast cancers. Recent investigations revealed that these two proteins may have a role in suppressing breast cancer progression. In this thesis, I will address their role in maintaining epithelial differentiating and inhibiting cell proliferation of breast epithelial cells. The epithelial to mesenchymal transition (EMT) is a developmental program in which epithelial cells downregulate their cell-cell junctions, acquire spindle cell morphology and exhibit cellular motility. In breast cancer, EMT facilitates invasion of surrounding tissues and correlates closely with cancer metastasis and relapse. We found previously that the candidate tumor suppressor hCLCA2 is a p53-inducible proliferation-inhibitor that is frequently lost in breast cancer. We show here that another member of the CLCA gene family, hCLCA4, is expressed in mammary epithelial cells and is similarly downregulated in breast tumors and in breast cancer cell lines. Like CLCA2, the gene is stress-inducible, and ectopic expression inhibits colony formation. Transcriptional profiling studies revealed that hCLCA4 and hCLCA2 together are markers for mammary epithelial differentiation, and both are downregulated by TGF beta. Moreover, knockdown of either on in immortalized cells by shRNAs caused downregulation of epithelial marker E-cadherin, while mesenchymal markers N-cadherin, vimentin, and fibronectin were upregulated, indicating an EMT program. Double knockdown of hCLCA2 and hCLCA4 enhanced the mesenchymal profile. These findings suggest that hCLCA4 and hCLCA2 play complementary but distinct roles in epithelial differentiation. Clinically, low expression of hCLCA2 and hCLCA4 signaled lower relapse-free survival in breast cancers. Cellular senescence is a program of irreversible cell cycle arrest in response to stressors such as DNA damage, ROS, telomere erosion, or oncogene activation. It is one of the primary tumor suppression mechanisms mediated by p53 and is often disabled in cancer cells. However, the downstream signaling pathway whereby p53 induces cellular senescence remains incomplete. We reported previously that hCLCA2 was a p53 inducible gene that is downregulated with breast cancer progression. We and other group noticed that hCLCA2 was induced in parallel with several types of senescence. Lentiviral transduction of CLCA2 into MCF7 cells inhibited cell proliferation and cells showed senescence phenotype. To investigate the mechanism biochemically, we used pAd-Easy to express hCLCA2 in the model breast cancer cell line CA1d. A protein expression profile of these cells over a 6 day period revealed induction of p21, p53, and the DNA damage-response pathway. To test whether hCLCA2 is required for the cellular senescence process, hCLCA2 was knocked down in HMLE. The knockdown cells (KD) and negative control were treated with a low concentration of doxorubicin, and cell proliferation was measured. The KD cells were more resistant to growth inhibition by doxorubicin. Moreover, a time course experiment showed that induction of SA beta-galactosidase, DNA damage response, and lysosomal markers IFI30 and CTSS was delayed in the knockdown cells. These results suggest that hCLCA2 plays an important role in DNA damage response and the senescence program.

La glycylation, une modification post-traductionnelle des microtubules, est cruciale dans le maintien des cils primaires. Notre groupe a précédemment identifié un rôle inattendu de la tubuline glycylase TTLL3 dans la régulation de l'homéostasie du colon et de la tumorigénèse. Plus précisément, une diminution du nombre de cils primaires a été observée chez les souris déficientes pour la glycylase TTLL3, qui est la seule glycylase exprimée dans le côlon. Les souris TTLL3 - / - ne présentent pas d'anomalie évidente à l'état stationnaire. Cependant, lorsqu'elles sont exposées à une carcinogenèse du côlon chimiquement induite, les souris TTLL3 - / - sont plus sensibles à la formation de tumeurs. Il est important de noter que les niveaux d'expression de TTLL3 sont significativement réduits dans les carcinomes primaires et métastases colorectales chez l'homme comparativement au tissu de côlon sain, ce qui suggère un lien entre la régulation des cils primaires par TTLL3 et le développement du cancer colorectal.L'objectif de mon projet de thèse était d'explorer l’effet de la modulation des cils primaires sur la carcinogenèse du côlon. J’ai ainsi démontré que le nombre de cils primaires diminue lors de la carcinogenèse du côlon chimiquement induite chez la souris. Notamment, j'ai découvert que les cils primaires du côlon sont principalement exprimés par les cellules mésenchymateuses. Pour mieux caractériser le rôle des cils primaires dans le côlon murin, j'ai étudié les conséquences de leur perte dans les cellules mésenchymateuses intestinaux. Pour cela, j'ai utilisé deux modèles de souris KO conditionnelles, pour la kinesin-3A (Kif3A) et le transport intra-flagellaire 88 (Ift88), deux molécules essentielles pour la formation des cils. Leur délétion spécifique dans les cellules mésenchymateuses intestinaux est obtenue par croisement des souches de souris Kif3Afl/fl et Ift88fl/fl des souris transgéniques collagène VI-cre. Bien que le promoteur colllagène VI ne soit actif que dans un sous-ensemble de cellules mésenchymateuses coliques, j'ai constaté que la diminution du nombre de cils primaires dans ces derniers favorise la colite chimiquement induite et la carcinogenèse. L'analyse par séquençage ARN des cellules mésenchymateuses coliques isolés de souris mutantes suggère un déclenchement de la signalisation Wnt et Notch chez les souris ColVIcre-Kif3Afl/fl. Nous confirmons actuellement ces résultats par qPCR et immunohistochimie. / Glycylation, a posttranslational modification of microtubules, is crucial in the maintenance of PC. Our group previously identified an unexpected role of the tubulin glycylase TTLL3 in the regulation of colon homeostasis and tumorigenesis. Specifically, a decreased number of primary cilia (PC) was observed in mice deficient for the glycylase TTLL3, which is the only glycyclase expressed in the colon. TTLL3-/- mice display no obvious abnormalities in the steady state. However, when exposed to chemically induced colon carcinogenesis, TTLL3-/- mice are more susceptible to tumor formation. Importantly, TTLL3 expression levels were significantly downregulated in human primary colorectal carcinomas and metastases as compared to healthy colon tissue, suggesting a link between TTLL3 regulation of PC and colorectal cancer development.The aim of my thesis project was to explore the relation of PC and colon carcinogenesis. In fact, I could demonstrate that the number of PC decreases during chemically induced colon carcinogenesis in mice. Notably, I discovered that PC in the colon are mostly expressed by fibroblasts. To better characterize the role of PC in murine colon, I studied the consequences of a loss of PC in intestinal fibroblasts. For this, I used two independent ciliary conditional knockout mice, kinesin-3A (Kif3A) and intraflagellar transport 88 (Ift88), both essential for cilia formation. Specific deletion in intestinal fibroblasts is obtained by crossing with colVI-cre transgenic mice. Though the colVI promoter is only active in a subset of colonic mesenchymal cells I found that the decreased number of PC in colonic mesenchymal cells promotes chemically induced colitis and carcinogenesis. RNAseq on isolated colonic mesenchymal cells of mutant mice suggests a triggering of Wnt and Notch signaling in ColVIcre-Kif3aflx/flx mice. We are presently validating these findings by qPCR and immunohistochemistryTaken together, I discovered that PC are expressed by at least a subset of colonic mesenchymal cells, which has not been described before. Decreased numbers of those PC renders mice more susceptible to colitis and colitis associated carcinogenesis.

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Centro de Pesquisas Gonçalo Moniz. Salvador, BA, Brasil / O diabetes é uma doença de alta prevalência que, frequentemente, induz o comprometimento do sistema nervoso periférico. Na neuropatia diabética periférica, os sintomas mais encontrados são os sensitivos, no qual a dor neuropática, condição crônica caracterizada por alodinia e hiperalgesia, é a mais debilitante. Esta, prejudica a qualidade de vida do paciente, sendo muitas vezes não responsiva aos métodos farmacológicos convencionais de tratamento. Diante desse panorama, o desenvolvimento de novas abordagens terapêuticas que possuam ação efetiva neste tipo de dor é de grande relevância. O uso da terapia celular no tratamento de lesões do sistema nervoso tem demonstrado resultados promissores e o potencial terapêutico de células-tronco na neuropatia experimental tem sido proposto. Neste estudo, avaliou-se o efeito de células-tronco mesenquimais derivadas da medula óssea (CMsMO) na neuropatia diabética periférica estabelecida em modelo experimental de diabetes induzido por estreptozotocina (ETZ). Quatro semanas após a indução do modelo por ETZ (80 mg/kg; ip; 3 dias consecutivos), os animais receberam uma administração endovenosa de CMsMO (1 x 106) ou veículo. O tratamento com gabapentina (30 mg/kg; v.o. a cada 12 horas durante seis dias consecutivos) foi usado como padrão ouro. Os limiares nociceptivos térmico e mecânico foram avaliados durante todo o período experimental (90 dias), pelos métodos de hargreaves e von Frey. A avaliação da função motora foi realizada pelo teste de rota-rod. Em diferentes tempos e para todos os grupos experimentais, foram realizadas coletas de segmentos da medula espinal (L4-L5) para dosagem de citocinas por ELISA e segmentos do nervo isquiático foram também coletados para avaliação de alterações morfológicas por microscopia óptica e eletrônica de transmissão. Os dados comportamentais demonstraram que o tratamento com CMsMO reduziu a mecanoalodinia e a hipoalgesia térmica, levando os limiares nociceptivos de animais neuropáticos a níveis similares aos de animais não neuropáticos. Do mesmo modo, a administração de CMsMO normalizou a função motora dos animais neuropáticos. Dados de microscopia mostraram que animais neuropáticos apresentaram atrofia axonal, redução do número de fibras mielínicas e aparente redução do numero de fibras amielínicas no nervo isquiático. Animais neuropáticos tratados com CMsMO tiveram menor ocorrência de atrofia axonal e não apresentaram redução do numero de fibras mielínicas ou amielínicas, em relação aos neuropáticos tratados com salina. Além disso, animais neuropáticos tratados com CMsMO apresentaram menores níveis espinais de IL-1β e TNF-α, e maiores de IL-10 e TGF-β, em relação aos animais neuropáticos não tratados. Esse conjunto de resultados indica que CMsMO produzem efeito antinociceptivo duradouro na neuropatia diabética, seguido de modificações no padrão fisiopatológico da doença, o que aponta a terapia celular como uma interessante alternativa para o controle da neuropatia diabética periférica dolorosa. / Diabetes is a highly prevalent disease which frequently compromises the peripheral nervous system. In peripheral diabetic neuropathy, the most frequent symptoms are sensitive, in which the neuropathic pain, chronic condition characterized by allodynia and hyperalgesia, is the most debilitating. Neuropathic pain affects the quality of patients’ lives, and is often not responsive to pharmacological conventional treatment methods. Against this background, the development of new therapeutic approaches that have an effective action in this type of pain is of great importance. The use of cell therapy in the treatment of lesions in the nervous system has shown promising results and the therapeutic potential of stem cells in experimental neuropathy has been proposed. In this study, we evaluated the effect of mesenchymal stem cells derived from bone marrow (CMsMO) in peripheral diabetic neuropathy established in experimental model of streptozotocin (STZ) induced diabetes in mice. Four weeks after the induction of the model by administration of STZ (80 mg/kg, ip; 3 days) the animals received an CMsMO by intravenous administration (1x106) or vehicle. The treatment with gabapentin (30 mg/kg, orally every 12 hours for six days) was used as the gold standard. The thermal and mechanical nociceptive thresholds were assessed throughout the entire experimental period (90 days), using Hargreaves and von Frey methods, respectively. Motor function evaluation of was conducted using the rotarod test. At different times, were analyzes conducted in spinal cord segments (L4-L5) to determine cytokines profile by ELISA. Sciatic nerve segments were also collected for evaluation of morphological changes by optical and electron transmission microscopy. According to the behavioral data, the CMsMO treatment reduced the mecanoalodinia and the thermal hypoalgesia, leading nociceptive thresholds of neuropathic animals to levels similar to those of non-neuropathic animals. Similarly, CMsMO administration normalized motor function of neuropathic animals. Microscopy data demonstrated that neuropathic animals had axonal atrophy and an apparent decrease of the number of myelinated fibers as well a reduction in the number of unmyelinated fibers in the sciatic nerve, but neuropathic animals treated with CMsMO had a lower incidence of axonal atrophy, showed no decrease in the number of myelinated fibers and no apparent decrease in the amount of unmyelinated fibers in relation to neuropathics treated with saline. Furthermore, neuropathic animals treated with CMsMO presented lower levels of spinal IL-1β and higher levels of TNF-α, and IL-10 and TGF-β compared to neuropathic animals that received saline. These data indicate that CMsMO produces a lasting analgesic effect in diabetic neuropathy, followed by changes in the pathophysiological disease pattern, which indicates cell therapy as an interesting alternative for the control of painful peripheral diabetic neuropathy.

L’arthrose est une maladie ostéoarticulaire fréquente et sans traitement curatif. Elle se manifeste par une dégénérescence du cartilage, associée à une altération des autres tissus de l’articulation. Dans ce contexte, les cellules souches mésenchymateuses (CSM) démontrent un effet thérapeutique. Afin d’identifier de nouveaux médiateurs de l’homéostasie articulaire, nous avons analysé le secrétome des CSM en nous focalisant sur les membres de la famille du facteur de croissance transformant β (TGFβ), une voie centrale dérégulée dans l’arthrose.Cette approche nous a permis d’identifier la protéine induite par le TGFβ (TGFβI ou βIGH3), pour laquelle nous avons évalué le rôle dans la différenciation des CSM et comparé l’expression dans les tissus articulaires de patients arthrosiques et de sujets sains.Nous montrons l’importance du TGFβI dans la régulation des processus de différenciation osseuse et chondrogénique des CSM. Nous mettons également en évidence une dérégulation au niveau transcriptionnel et protéique de ce facteur dans le cartilage, l’os sous-chondral ainsi que les CSM de patients arthrosiques. En testant son implication dans l’effet thérapeutique des CSM sur des modèles d’arthrose in vitro et in vivo, nous montrons que la diminution de son expression dans les CSM annule leur effet thérapeutique dans les modèles d’arthrose. Cet effet chondroprotecteur du TGFβI est associé à une inhibition du remodelage osseux et de la calcification des tissus mous articulaires.L’ensemble de nos résultats démontrent l’importance de la régulation de la voie TGFβ, et plus particulièrement du TGFβI, dans l’homéostasie articulaire. En parallèle, nos travaux illustrent le rôle de ce facteur dans l’effet thérapeutique des CSM, et suggèrent que l’altération de son expression dans les CSM de patients arthrosiques soit à l’origine d’une diminution de leur potentiel régénératif. / Osteoarthritis (OA) is the most common form of joint diseases without curative treatments. The disease is mainly characterized by the degradation of articular cartilage which is associated with other pathological changes in joint tissues. In this context, mesenchymal stem cells (MSC) have demonstrated a therapeutic effect. In order to identify new mediators involved in articular homeostasis, we analyzed MSC secretome, focusing on the transforming growth factor β (TGFβ) members, a central pathway dysregulated in OA.This approach allows us to identify the TGFβ induced protein (TGFβI or βIGH3). In the present study, we evaluated its role in the differentiation of MSC and compared its expression in articular tissues from OA patients and healthy donors.We highlight the importance of TGFβI in the regulation of differentiation of MSC towards bone and cartilage. We also demonstrate its dysregulation at both transcript and protein level in cartilage, bone and MSC from OA patients. We then evaluated its role in the therapeutic effect of MSC in vitro and in vivo and demonstrated that its decreased expression in MSC is associated with a loss of their therapeutic effect in OA models. The chondroprotective effect of TGFβI is associated with an inhibition of bone remodeling and calcification of soft articular tissues.Together, our results highlight the importance of the TGFβ pathway, and specially of TGFβI regulation, in joint homeostasis. Moreover, our work demonstrates its role in the therapeutic effect of MSC, suggesting that its dysregulation in OA MSC could lead to a decreased regenerative potential.

O diabetes mellitus tipo 1 é uma doença autoimune causada pela destruição das células β produtoras de insulina, presentes nas ilhotas pancreáticas, por células autorreativas do sistema imune. A opção de tratamento mais utilizada são injeções diárias de insulina exógena, o que configura um tratamento não curativo. Para alcançar a independência de insulina, alternativas como o transplante de ilhotas vêm sendo estudadas. Entretanto, a disponibilidade de pâncreas de doadores cadavéricos para o isolamento destas ilhotas é pequena e os métodos de isolamento, pouco eficazes, sendo necessários de 2 a 4 doadores para atingir o número adequado de ilhotas. Além disso, o transplante apresenta problemas relacionados à enxertia, devidos principalmente à baixa vascularização, o que leva à morte de células β nos primeiros dias pós-transplante. Desta forma, estudos explorando alternativas que aumentem a sobrevivência e a funcionalidade dos transplantes e diminuam o número de ilhotas exigido por receptor fazem-se muito necessários. As células-tronco mesenquimais apresentam propriedades interessantes para aplicação em terapia celular. Entre elas, destaca-se o efeito parácrino, que exerce diversas funções benéficas, como o aumento da vascularização, nos locais onde estas células estão presentes. Sendo assim, este trabalho explorou o co-transplante de ilhotas pancreáticas com células-tronco mesenquimais derivadas de tecido adiposo, para o tratamento do diabetes mellitus em modelo murino. Os resultados mostraram que a presença destas células no grupo que recebeu o co-transplante não aumentou a taxa de cura, em relação ao grupo que recebeu somente ilhotas. No entanto, o fenômeno de reversão do diabetes foi antecipado no grupo co-transplantado, o que sugere um possível efeito angiogênico das células-tronco adiposo-derivadas presentes neste grupo. Desta forma, conclui-se que estas células podem exercer atividades benéficas, quando co-transplantadas com ilhotas pancreáticas, para o tratamento do diabetes. / Type 1 diabetes mellitus is an autoimmune disease caused by destruction of insulin-producing β cells, present in pancreatic islets, by auto-reactive cells of the immune system. The most widely used treatment option are daily injections of insulin, which configures a non-curative treatment. To achieve insulin independence, alternatives such as islet transplantation have been studied. However, the availability of pancreas from cadaveric donors for the isolation of these islets is poor and the methods for isolation, ineffective, requiring 2 to 4 donors to achieve the appropriate number of islets. In addition, transplantation presents problems related to engraftment, mainly due to poor vascularization, which leads to β cell death in the first days after transplantation. Thus, studies exploring alternatives that increase the survival and function of transplants and reduce the number of islets required by the recipient are very necessary. Mesenchymal stem cells have interesting properties for application in cell therapy. Among them is the paracrine effect, which has several beneficial functions, such as promoting vascularization in the tissues where these cells are present. Thus, the present study explored the co-transplantation of pancreatic islets with mesenchymal stem cells derived from adipose tissue for the treatment of diabetes mellitus in mice. The results showed that the presence of these cells in the group that received co-transplantation did not increase the cure rate, compared to the group that received islets alone. However, the phenomenon of diabetes reversion was anticipated in co-transplanted animals, which suggests a possible angiogenic effect of adipose-derived stem cells present in this group. Thus, we conclude that these cells may exert beneficial functions when co-transplanted with pancreatic islets for the treatment of diabetes.