L’arthrose ou ostéoarthrose (OA) est l’affection rhumatologique la plus fréquente au monde. Elle est caractérisée principalement par une perte du cartilage articulaire et l’inflammation de la membrane synoviale. L’interleukine (IL)-1ß, une cytokine pro-inflammatoire, joue un rôle très important dans la pathogenèse de l’OA. Elle exerce son action en induisant l’expression des enzymes cyclo-oxygénase 2 (COX-2), prostaglandine E synthétase microsomale 1 (mPGES-1) et l’oxyde nitrique synthétase inductible (iNOS) ainsi que la production de la prostaglandine E2 (PGE2) et de l’oxyde nitrique (NO). Ces derniers (PGE2 et NO) contribuent à la synovite et la destruction du cartilage articulaire par leurs effets pro-inflammatoires, pro-cataboliques, anti-anaboliques, pro-angiogéniques et pro-apoptotiques. Les modifications épigénétiques, telles que la méthylation de l’ADN, et l’acétylation et la méthylation des histones, jouent un rôle crucial dans la régulation de l’expression des gènes. Parmi ces modifications, l’acétylation des histones est la plus documentée. Ce processus est contrôlé par deux types d’enzymes : les histones acétyltransférases (HAT) qui favorisent la transcription et les histones déacétylases (HDAC) qui l’inhibent. L’objectif de ce travail est d’examiner le rôle des enzymes HDAC dans la régulation de l’expression de la COX-2, mPGES-1 et iNOS. Nous avons montré qu’au niveau des chondrocytes, les inhibiteurs des HDAC (iHDAC), trichostatine A (TSA) et butyrate de sodium (NaBu), suppriment l’expression de la COX-2 et iNOS au niveau de l’ARNm et protéique, ainsi que la production de la PGE2 et du NO, induites par l’IL-1ß. L’effet inhibiteur à lieu sans affecter l’activité de liaison à l’ADN du facteur de transcription NF-κB (nuclear factor κ B). La TSA et le NaBu inhibent également la dégradation induite par l’IL-1ß des protéoglycanes au niveau du cartilage. Nous avons également montré, qu’au niveau des fibroblastes synoviaux, les iHDAC, TSA, NaBu et acide valproïque (VA), suppriment l’expression de la mPGES-1 ainsi que la production de la PGE2 induites par l’IL-1ß. En utilisant diverses approches expérimentales, nous avons montré que HDAC4 est impliquée dans l’induction de l’expression de la mPGES-1 par l’IL-1ß. HDAC4 exerce son action, via son activité déacétylase, en augmentant l’activité transcriptionnelle de Egr-1 (early growth factor 1), facteur de transcription principal de l’expression de la mPGES-1. L’ensemble de ces résultats suggère que les inhibiteurs des HDAC pourraient être utilisés dans le traitement de l’OA. / Osteoarthritis (OA) is the most common form of arthritic diseases in the world. It is primarily characterized by the loss of articular cartilage and inflammation of the synovial membrane. Interleukin (IL)-1ß is a pro-inflammatory cytokine that plays a major role in the pathogenesis of OA. It induces the expression of cyclo-oxygenase 2 (COX-2), microsomal prostaglandin E synthase-1 (mPGES-1), inducible nitric oxide synthase (iNOS), as well as the production of prostaglandin E2 (PGE2) and nitric oxide (NO). The later (PGE2 and NO) contribute to articular cartilage destruction and synovitis through their pro-inflammatory, pro-catabolic, anti-anabolic, pro-angiogenic and pro-apoptotic effects. Epigenetic modifications such as DNA methylation, histone acetylation and methylation play a crucial role in gene expression. Among these modifications, histone acetylation is the most studied. Histone acetylation is determined by two types of enzymes: histone acetyltransferases (HAT) and histone deacetylases (HDAC) which activate and repress transcription, respectively. The purpose of these studies is to examine the role of HDAC enzymes in the regulation of COX-2, mPGES-1, and iNOS expression. We demonstrated that HDAC inhibitors (HDACi), trichostatin A (TSA) and sodium butyrate (NaBu), suppressed the Il-1ß-induced transcription and translation of COX-2 and iNOS, as well as the production of PGE2 and NO in chondrocytes. The inhibitory effect of HDACi on transcription does not affect the binding activity of NF-κB (nuclear factor κ B) to DNA. Treatment with TSA and NaBu also inhibited the Il-1ß-induced degradation of proteoglycan in cartilage explants. We also showed that HDACi, TSA, NaBu and valproic acid (VA), suppressed IL-1-induced-mPGES-1 expression and the production of PGE2 in synovial fibroblasts. Our data indicated that HDAC4 is involved in Il-1ß-induced expression of mPGES-1. HDAC4, through its deacetylase activity, up-regulated the transcriptional activity of Egr-1 (early growth factor-1), a principal transcription factor for the expression of mPGES-1. From our studies we propose that HDAC inhibitors can be used in the treatment of OA.

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Submitted by GABRIELLI BRIANEZI null (gabrielli.brianezi@hotmail.com) on 2016-02-26T15:36:13Z No. of bitstreams: 1 20160224 Tese Gabrielli Brianezi.pdf: 3073309 bytes, checksum: 8fd0793265926aa1a58aea12aad689a6 (MD5) / Approved for entry into archive by Ana Paula Grisoto (grisotoana@reitoria.unesp.br) on 2016-02-26T20:04:11Z (GMT) No. of bitstreams: 1 brianezi_g_dr_bot.pdf: 3073309 bytes, checksum: 8fd0793265926aa1a58aea12aad689a6 (MD5) / Made available in DSpace on 2016-02-26T20:04:11Z (GMT). No. of bitstreams: 1 brianezi_g_dr_bot.pdf: 3073309 bytes, checksum: 8fd0793265926aa1a58aea12aad689a6 (MD5) Previous issue date: 2016-01-26 / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / A patogênese do melasma, especialmente o papel dos queratinócitos e fibroblastos no desenvolvimento e manutenção da doença não é bem compreendida. Alterações dérmicas como dano estrutural à zona de membrana basal, melanócitos em pêndulo, elastose solar, celularidade, proliferação vascular, além da expressão de mediadores inflamatórios, fatores de crescimento, expressão epitelial de melanocortina e receptores dos hormônios sexuais; sugerem interação entre a unidade epidermo-melânica e a derme na fisiopatologia do melasma. A pigmentação melânica da pele pode ser estimulada por diferentes vias de sinalização, sendo a radiação ultravioleta, citocinas dérmicas e inflamação epidérmica, os modelos mais usuais. Neste estudo, objetivamos comparar a morfologia nuclear e a textura da cromatina entre queratinócitos basais no melasma facial e pele adjacente, investigar a ativação das diferentes vias de estímulo à pigmentação, além do envolvimento da derme, com foco na zona de membrana basal e colágeno, no melasma facial. Para a sua execução, foram coletados pares de biópsias faciais (2mm) de mulheres adultas com melasma e de pele adjacente (<2 cm). Processaram-se para coloração de PAS e picrosirius red; imunofluorescência para p53, p38, IL- 1α, αMSH, MC1R e COX2; imunoistoquímica para Melan-Acontracorada com PAS; Microscopia Eletrônica de Transmissão, além de cultura primária de fibroblastos para real-timePCR array e marcação para SA-β-gal. Foram avaliados: núcleos de queratinócitos da camada basal quanto à morfometria nuclear e textura da cromatina; quantificada a intensidade de fluorescência nos compartimentos da epiderme e derme; avaliadas organelas citoplasmáticas e zona de membrana basal; além do colágeno dérmico e densidade de melanócitos: totais e em pêndulo. Em relação à pele adjacente sem melasma: núcleos de queratinócitos basais da epiderme com melasma facial apresentaram índices morfométricos e textura da cromatina alterados; houve aumento da expressão epitelial de αMSH e MC1R, sem diferença quanto ao p53, p38, IL1α e COX2; houve maior número de organelas citoplasmáticas e melanossomas em estágios de maturação maiores nos queratinócitos e melanócitos; áreas danificadas na zona de membrana basal com presença de microvesículas adjacentes à membrana basal; maior número de melanócitos em pêndulo; colágeno dérmico desestruturado. Entre os fibroblastos, houve maior marcação para SA-β-gal e expressão alterada dos genes COL4A1, IL6, ESR2, DKK3, CCL2, WIF1, WNT3A, HGF, IL1B, MMPs 1-7-9 no melasma. As alterações encontradas nos queratinócitos, na derme e zona de membrana basal, sugerem que o fenótipo do melasma pode resultar de alterações em toda unidade epidermo-melânica, não somente de uma hipertrofia dos melanócitos, as vias inflamatórias da epiderme e dependentes de p53 não se mostraram proeminentes, além de ser identificado um possível papel do processo de reparo/dano da derme e da senescência de fibroblastos na patogênese da doença. / The melasma pathogenesis, specially the role of keratinocytes and fibroblast in the disease development and maintenance are not completely understood. Dermal alterations such as basal membrane structural damage, pendulous melanocytes, solar elastosis, cellularity, vascular proliferation, in addition to the expression of inflammatory mediators, grow factors, epithelial melanocortin and sexual hormones receptors, suggest there is an interaction between the epidermal melanin unit and dermis in melasma physiopathology. The melanin skin pigmentation can be stimulated by different signaling pathways. UVR, dermal cytokines and epidermal inflammation are the most common models. These study aims to compare the nuclear morphology and chromatin texture in basal keratinocytes between melasma and adjacent skin, to investigate the activation of different pigmentation signaling pathways, and the dermal involvement, focusing on basal membrane zone and collagen. Therefore, facial skin biopsies (2 mm) from women were taken from melasma and normal skin (<2 cm apart) and processed for PAS and picrosirius red; immunofluorescence for p53, p38, IL-1α, αMSH, MC1R and COX2, immunohistochemistry for Melan-A counterstaining with PAS, and transmission electronic microscopy. Furthermore, primary fibroblast culture for real-timePCRarray and SA-β-gal staining. The nuclei of basal keratinocytes were evaluated as nuclear morphometry and chromatin texture; the fluorescence intensity was quantified in the epidermis and dermis; cytoplasm organelles and basal membrane zone were evaluated; in addition to dermal collagen and melanocytes density: total and pendulous. Regarding adjacent healthy skin, the melasma skin showed alterations in morphometric index and chromatin texture; there was greater epithelial expression of αMSH and MC1R, but without difference for p53, p38, IL1α and COX2; cytoplasm organelles and melanossomas in higher maturity were in greater number in keratinocytes and melanocytes; there were commoner damaged areas in basal membrane zone, presence of microvesicules adjacent to basal membrane; and higher number of pendulous melanocyte; dermal collagen was less structured. There were greater SA-β-gal staining and altered expression of COL4A1, IL6, ESR2, DKK3, CCL2, WIF1, WNT3A, HGF, IL1B, MMPs 1-7-9 genes in melasma fibroblasts.The alterations presented in keratinocytes, dermis and basal membrane zone suggest the melasma phenotype can result from alteration in entire epidermal melanin unit, not just hypertrophic melanocytes, the epidermal inflammatory pathways and p53 dependents do not show prominence, in addition to the possible role of the repair/ damage process identified at dermis and fibroblast senescence in the melasma pathogenesis. / FAPESP: 12/09233-5 / FAPESP: 12/05004-1

Modifying the metabolism of the body’s own endocannabinoids is a novel approach for analgesia. Two key catabolic enzymes are fatty acid amide hydrolase (FAAH) and inflammation-inducible cyclooxygenase 2 (COX-2). The cellular uptake of the key endocannabinoid anandamide (AEA) has been found to be regulated by its FAAH-catalysed intracellular degradation, but COX-2 has not been investigated in this respect. We aimed to find out whether or not COX-2 in an in vitro inflammation setting would be able to gate AEA uptake. To achieve this, C6 cells and Raw 264.7 cells were stimulated with LPS/INF-γ and lysates then analyzed by immunoblot in order to verify COX-2 expression. AEA cellular uptake was quantified using a radioassay with [3H]-AEA. It was found that COX-2 was not inducible in C6 cells using the LPS/INF-γ conditions studied, while it was inducible in Raw 264.7 cells. AEA uptake in the COX-2-induced Raw 264.7 cells was not reduced by inhibitors of this enzyme. FAAH appeared to be down-regulated in the stimulated Raw 264.7 cells, and this was reflected in an overall lower AEA uptake. Our interpretation of the data points to FAAH as gating AEA uptake. Additional experiments are required to validate our findings by verifying significance.