Ce travail de thèse a eu pour thème principal le protéoglycane syndecan-1 au cours du myélome multiple, une hémopathie maligne caractérisée par la présence d'un clone de plasmocytes tumoraux au sein de la moelle osseuse. Syndecan-1 est un élément majeur de la physiopathologie du myélome multiple, ce protéoglycane étant au coeur d'un réseau complexe d'interactions moléculaires conditionnant le devenir des cellules plasmocytaires tumorales.Les chaînes de glycosaminoglycanes présentes sur le core protéique de syndecan-1sont responsables d'une grande partie de son activité. Nous avons ainsi caractérisé, par une approche transcriptomique, 100 gènes codant les protéines impliquées dans la synthèse et la modification de ces chaînes. Nous avons de cette manière identifié des cibles moléculairesen vue de moduler, voire d'inhiber leur activité.Dans le but d'identifier les métalloprotéinases des familles ADAM et ADAMTS susceptibles d'interagir avec syndecan-1, nous avons réalisé l'étude du profil d'expression des gènes codant ces reprolysines et leurs inhibiteurs dans les cellules de la différentiation lymphocytaire B, les cellules plasmocytaires normales et tumorales ainsi que dans l'environnement médullaire.Dans une dernière partie, nous avons évalué l'efficacité d'une approche d'inhibitiondes chaînes héparanes sulfates via l'utilisation de l'héparine. Nous observons que certaines lignées myélomateuses sont inhibées par l'héparine et ses dérivés et que ces mêmes lignées sont stimulées par l'antidote de l'héparine, le sulfate de protamine. Les mécanismes mis enjeu sont en relation avec la modulation de la biodisponibilité des facteurs permettant la croissance des cellules. / Multiple myeloma is a hematological malignancy characterized by the expansion of aclone of malignant plasma cells in the bone marrow compartment. Syndecan-1 is a majorproteoglycan involved in a complex network of molecular interactions in multiple myelomaphysiopathology. As heparan sulfate and chondroitin sulfate chains are the bioactive components ofsyndecan-1, we first analysed the signature of genes encoding 100 proteins involved in thesynthesis of these chains, from precursor uptake to post-translational modifications, usingAffymetrix microarrays.In order to identify the metalloproteinases belonging to ADAM and ADAMTS familiespotentially implicated in the interactions with syndecan-1, we performed a gene expressionprofile focused on the genes encoding these reprolysines and their inhibitors.In a last part, we evaluated the efficacy of an inhibitory approach based on theutilization of heparin in human myeloma cell lines in vitro, inhibitory effects being in relationwith a modulation of the biodisponibility of heparin-binding factors.This work led us to identify targets of interest in relation with syndecan-1 biology inmultiple myeloma. They could be used to design new therapeutic strategies.

A cartilagem articular da cabeça da mandíbula (CAM) é constituída por uma cartilagem secundária recoberta por tecido conjuntivo fibroso e, portanto, definida como fibrocartilagínea. Ela é constantemente submetida a forças de compressão e cisalhamento decorrentes da mastigação necessitando de lubrificação e capacidade de reparo. O envelhecimento é considerado um dos principais fatores para o aparecimento de alterações degenerativas nas articulações sinoviais. A lubricina é reconhecidamente um proteoglicano encontrado nas cartilagens articulares cuja função primordial é a lubrificação limítrofe. A via SMAD2, tem sido associada à capacidade de manutenção e reparo da cartilagem, e a sua fosforilação na cadeia de ligação (p-SMAD2L) foi relacionada ao aumento no tempo de fosforilação na cadeia C-terminal (p-SMAD2) e da transcrição gênica. Objetivo: Estudar as alterações morfológicas da CAM e as expressões da lubricina, p-SMAD2L e do colágeno tipo I no envelhecimento. Métodos: cortes coronais da CAM de ratos wistar com 2, 12 e 24 meses de vida foram corados pelas técnicas da hematoxilina e eosina, azul de toluidina e safranina-O. A imuno-histoquímica foi usada para detectar a localização da lubricina, p-SMAD2L e colágeno tipo I. Resultados: Notou-se modificações estruturais atribuídas ao processo natural do envelhecimento da CAM. Ainda, se verificou um aumento do colágeno tipo I nas camadas mais profundas e cartilaginificação da matriz extracelular (MEC) nas camadas superficiais. No grupo idoso, houve redução na concentração de proteoglicanos, na expressão da lubricina e na densidade e porcentagem de células p-SMAD2L. Conclusões: a CAM sofre modificações com o envelhecimento, inclusive degenerativas, e diminui sua capacidade de lubrificação e reparo em virtude da menor expressão da lubricina e p-SMAD2L. Sugere-se que a p-SMAD2L está envolvida na produção e acúmulo da lubricina na CAM / The mandibular condylar cartilage (MCC) consists of a secondary cartilage covered by fibrous connective tissue and, therefore, defined as fibrocartilage. It is constantly subjected to compression and shear forces resulting from chewing requiring lubrication and repair capability. Aging is considered one of the main factors for the appearance of degenerative changes in synovial joints. Lubricin is a proteoglycan found in articular cartilages whose primary function is boundary lubrication. SMAD2 signaling pathway has been associated with cartilage maintenance and repair, and its phosphorylation in the linker region (p-SMAD2L) was related to the increase in half-life of C-terminal phospho-SMAD2 (p-SMAD2) and gene transcription. Objective: To study the morphological alterations of MCC and the expressions of the lubricin, p-SMAD2L and type I collagen in aging. Methods: Coronal sections of the MCC from wistar rats with 2, 12 and 24 months old were stained with hematoxylin and eosin, toluidine blue and safranin-O. Immunohistochemistry were used for detection of lubricin, p-SMAD2L and type I collagen. Also, the total cell density, p-SMAD2L cells density and percentage were determined. Results: Structural modifications of the MCC related with natural aging process were observed. An increase in the expression of type I collagen in the deeper layers and \"cartilaginification\" of the extracellular matrix (ECM) in the superficial layers were detected. In the old group, it was observed a reduction in proteoglycan content, in the expression of the lubricin and in the density and percentage of positive cells for the p-SMAD2L. Conclusion: MCC undergoes structural and degenerative modifications with aging and decreases its lubrication and repair capacity due to the lower expression of the lubricin and p-SMAD2L. This study suggests that p-SMAD2L is involved in the production and accumulation of the lubricin in MCC

<p>Heparan sulfate (HS) is a ubiquitous polysaccharide on the cell surface and in the extracellular matrix. HS is an important actor in the regulation of cell signaling, especially in the developing embryo. In combination with cell culture and biochemical experiments, <i>in vivo</i> studies of genetically modified animals have pointed out the sulfation pattern of HS as highly important for binding of ligands, their receptors and other signaling modulators.</p><p>The sulfation pattern of an HS chain is gained by several modifying steps, performed by multiple enzymes during biosynthesis in the Golgi apparatus. By alterations of sulfation pattern, and the amount of sulfate groups, a cell can regulate the binding properties of its HS to different molecules. The most highly sulfated form of HS is called heparin, and can only be found intracellularly in mast cells.</p><p>This thesis describes the phenotypes and the alterations in HS/heparin biosynthesis of two genetically modified mouse strains deficient in N-deacetylase/N-sulfotransferase-1 (NDST1) and -2 (NDST2) respectively. We have found NDST1 to be important for correct sulfation of HS and that NDST2 is crucial in heparin biosynthesis. NDST2 deficient mice completely lack heparin and therefore have a severe mast cell phenotype. NDST1 deficient mice produce undersulfated HS and show several developmental disturbances. Some NDST1 embryos die in utero while the rest die neonatally due to breathing difficulties. Defect brain, eye and skeletal development has also been observed while some organs, such as the liver, appear to be largely unaffected. Several phenotypes are similar to defects seen in other mouse strains with impaired fibroblast growth factor and bone morphogenetic protein signaling, among others. This suggests the phenotypes of NDST1 deficient embryos to be of a multi factorial origin, in complete accordance to the many signaling pathways HS is suggested to modulate.</p>

<p>Heparan sulfate (HS) proteoglycans consist of sulfated HS chains covalently bound to core proteins. They are ubiquitously expressed, on the cell surface and in the extracellular matrix, throughout the body. During biosynthesis the HS chain is modified to generate a highly variable pattern of sulfated residues, able to interact with a wide variety of ligands, such as growth factors, morphogens and extracellular matrix molecules. The presence of HS proteoglycans is crucial during various developmental processes as they are involved in generation of morphogen gradients and influence the function of several growth factor pathways essential for tissue assembly and differentiation.</p><p>In this thesis the phenotypes of two mouse strains, deficient in different isoforms of the HS biosynthetic enzyme N-deacetylase/N-sulfotransferase (NDST) have been analyzed. In addition, NDST deficient embryonic stem (ES) cells have been analyzed with regard to HS structure and differentiation capacity. Mice deficient in NDST1 die peri-natally. The embryos display an overall low-sulfated HS and several developmental defects, with a lung phenotype as the predominant cause of death. Mice deficient in NDST2 lack sulfated heparin in connective tissue type mast cells while HS structure is unaltered. These results indicate that NDST1 is the isoform mainly responsible for HS biosynthesis during development. However, NDST1/2 deficient embryos do not survive beyond E5.5 and have a greatly disturbed morphology, suggesting that NDST2 has an essential role during early embryonic development. HS synthesized by NDST1/2 deficient ES cells had a total lack of N-sulfate groups while, interestingly, about half of the 6-O-sulfate groups remained. This result was unexpected since 6-O-sulfotransferases have been thought to be strictly dependent on N-sulfate groups for substrate recognition. Further characterization of the NDST1/2 deficient ES cells during in vitro differentiation demonstrated that the expression pattern of markers for all three germ layers was disturbed. In addition, it was demonstrated that NDST1 is not needed for mast cell development, that lack of NDST2 results in abnormal mast cells and that no mast cells is formed from NDST1/2 deficient ES cells.</p>

Heparan sulfate (HS) is a ubiquitous polysaccharide on the cell surface and in the extracellular matrix. HS is an important actor in the regulation of cell signaling, especially in the developing embryo. In combination with cell culture and biochemical experiments, in vivo studies of genetically modified animals have pointed out the sulfation pattern of HS as highly important for binding of ligands, their receptors and other signaling modulators. The sulfation pattern of an HS chain is gained by several modifying steps, performed by multiple enzymes during biosynthesis in the Golgi apparatus. By alterations of sulfation pattern, and the amount of sulfate groups, a cell can regulate the binding properties of its HS to different molecules. The most highly sulfated form of HS is called heparin, and can only be found intracellularly in mast cells. This thesis describes the phenotypes and the alterations in HS/heparin biosynthesis of two genetically modified mouse strains deficient in N-deacetylase/N-sulfotransferase-1 (NDST1) and -2 (NDST2) respectively. We have found NDST1 to be important for correct sulfation of HS and that NDST2 is crucial in heparin biosynthesis. NDST2 deficient mice completely lack heparin and therefore have a severe mast cell phenotype. NDST1 deficient mice produce undersulfated HS and show several developmental disturbances. Some NDST1 embryos die in utero while the rest die neonatally due to breathing difficulties. Defect brain, eye and skeletal development has also been observed while some organs, such as the liver, appear to be largely unaffected. Several phenotypes are similar to defects seen in other mouse strains with impaired fibroblast growth factor and bone morphogenetic protein signaling, among others. This suggests the phenotypes of NDST1 deficient embryos to be of a multi factorial origin, in complete accordance to the many signaling pathways HS is suggested to modulate.

Chondroitin sulfate proteoglycans (CSPGs) are one major class of axon growth inhibitors that are upregulated and accumulated around the lesion site after spinal cord injury (SCI), and result in regenerative failure. To overcome CSPG-mediated inhibition, digestion of CSPGs with chondroitinase ABC (chABC) has been explored and it has shown promising results. chABC digests glycosaminoglycan chains on CSPGs and can thereby enhance axonal regeneration and promote functional recovery when delivered at the site of injury. However, chABC has a crucial limitation; it is thermally unstable and loses its enzymatic activity rapidly at 37 ºC. Therefore, it necessitates the use of repeated injections or local infusions with a pump for days to weeks to provide fresh chABC to retain its enzymatic activity. Maintaining these infusion systems is invasive and clinically problematic. In this dissertation, three studies are reported that demonstrate our strategy to overcome current limitations of using chABC and develop a delivery system for facilitating chABC treatment after SCI: First, we enhanced the thermostability of chABC by adding trehalose, a protein stabilizer, and developed a system for its sustained local delivery in vivo. Enzymatic activity was assayed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and dimethylmethylene blue (DMMB), and conformational change of the enzyme was measured via circular dichroism (CD) with and without trehalose. When stabilized with trehalose, chABC remained enzymatically active at 37 ºC for up to 4 weeks in vitro. We developed a lipid microtube-agarose hydrogel delivery system for a sustained release and showed that chABC released from the delivery system is still functionally active and slowly released over 2 weeks in vitro. Second, the hydrogel-microtube system was used to locally deliver chABC over two weeks at the lesion site following a dorsal over hemisection injury at T10. The scaffold consisting of hydrogel and chABC loaded lipid microtubes was implanted at the top of the lesion site immediately following injury. To determine effectiveness of topical delivery of thermostabilized chABC, animal groups treated with single injection or gel scaffold implantation of chABC and penicillinase (P'ase) were included as controls. Two weeks after surgery, the functionality of released chABC and the cellular responses were examined by immunohistological analysis with 3B3, CS-56, GFAP and Wisteria floribunda agglutinin (WFA). The results demonstrated that thermostabilized chABC was successfully delivered slowly and locally without the need for an indwelling catheter by using the hydrogel-microtube delivery system in vivo. The results demonstrated that released chABC from the gel scaffold effectively digested CSPGs, and therefore, there were significant differences in CSPG digestion at the lesion site between groups treated with chABC loaded microtube-hydrogel scaffolds and controls. Third, a long term in vivo study (45 days) was conducted to examine axonal sprouting/regeneration and functional recovery with both a single treatment each of microtube loaded chABC or Neurotrophin-3 (NT-3), and a combination of them by using the hydrogel-microtube delivery system. Over the long term study period, the treated animals showed significant improvement in locomotor function and more sprouting of cholera toxin B subunit (CTB)-positive ascending dorsal column fibers and 5-HT serotonergic fibers around the lesion site. We demonstrated that this significant improvement of chABC thermostability facilitates the development of a minimally invasive method for sustained, local delivery of chABC that is potentially a useful and effective approach for treating SCI. In addition to that, we demonstrated that combinatorial therapy with chABC and neurotrophic factors could provide a synergistic effect on axonal regrowth and functional recovery after SCI.

Heparan sulfate (HS) proteoglycans consist of sulfated HS chains covalently bound to core proteins. They are ubiquitously expressed, on the cell surface and in the extracellular matrix, throughout the body. During biosynthesis the HS chain is modified to generate a highly variable pattern of sulfated residues, able to interact with a wide variety of ligands, such as growth factors, morphogens and extracellular matrix molecules. The presence of HS proteoglycans is crucial during various developmental processes as they are involved in generation of morphogen gradients and influence the function of several growth factor pathways essential for tissue assembly and differentiation. In this thesis the phenotypes of two mouse strains, deficient in different isoforms of the HS biosynthetic enzyme N-deacetylase/N-sulfotransferase (NDST) have been analyzed. In addition, NDST deficient embryonic stem (ES) cells have been analyzed with regard to HS structure and differentiation capacity. Mice deficient in NDST1 die peri-natally. The embryos display an overall low-sulfated HS and several developmental defects, with a lung phenotype as the predominant cause of death. Mice deficient in NDST2 lack sulfated heparin in connective tissue type mast cells while HS structure is unaltered. These results indicate that NDST1 is the isoform mainly responsible for HS biosynthesis during development. However, NDST1/2 deficient embryos do not survive beyond E5.5 and have a greatly disturbed morphology, suggesting that NDST2 has an essential role during early embryonic development. HS synthesized by NDST1/2 deficient ES cells had a total lack of N-sulfate groups while, interestingly, about half of the 6-O-sulfate groups remained. This result was unexpected since 6-O-sulfotransferases have been thought to be strictly dependent on N-sulfate groups for substrate recognition. Further characterization of the NDST1/2 deficient ES cells during in vitro differentiation demonstrated that the expression pattern of markers for all three germ layers was disturbed. In addition, it was demonstrated that NDST1 is not needed for mast cell development, that lack of NDST2 results in abnormal mast cells and that no mast cells is formed from NDST1/2 deficient ES cells.

Η σεργλυκίνη (SG) είναι η κύρια πρωτεογλυκάνη που εκφράζεται από τα αιμοποιητικά κύτταρα και συμμετέχει στη ρύθμιση διαφόρων παραγόντων που εμπλέκονται στις αντιδράσεις φλεγμονής. Επιπλέον, φαίνεται ότι διαδραματίζει σημαντικό ρόλο στη βιολογία του πολλαπλού μυελώματος αφού αναστέλλει τη δραστικότητα της κλασικής οδού και της λεκτινικής οδού του συμπληρώματος και προάγει την προσκόλληση των μυελωματικών κυττάρων στο κολλαγόνο τύπου Ι. Παράλληλα, η αυξημένη έκφρασή της σχετίζεται με τον επιθετικό φαινότυπο των κυττάρων καρκίνου του ρινοφάρυγγα. Στην παρούσα διατριβή μελετήθηκε η έκφραση της SG σε κακοήθειες. Τα αποτελέσματά μας αναδεικνύουν την έντονη παρουσία της σε συμπαγείς όγκους λόγω της αυξημένης έκφρασή της είτε από τα καρκινικά κύτταρα είτε από τα κύτταρα φλεγμονής και τα κύτταρα του στρώματος τα οποία επιστρατεύονται κατά την ανάπτυξη του όγκου. Επιπλέον, η αυξημένη έκφρασή της και η έκκρισή της σχετίσθηκαν με το μεταστατικό δυναμικό των κυτταρικών σειρών διαφόρων τύπων καρκίνου. Παράλληλα, ταυτοποιήθηκε η έκφραση του μεταγράφου της SG που προκύπτει από εναλλακτικό μάτισμα με απαλοιφή του εξωνίου 2. Επιπροσθέτως, μελετήθηκε ο βιολογικός ρόλος της SG σε επιθετικά καρκινικά κύτταρα μαστού. Βρέθηκε ότι η SG αλληλεπιδρά με πρωτεΐνες που διαδραματίζουν σημαντικό ρόλο σε κυτταρικές λειτουργίες όπως η αναδιοργάνωση του κυτταροσκελετού, η μεταφορά και ανακύκλωση μορίων από και προς την κυτταρική επιφάνεια και η γονιδιακή ρύθμιση. Η ίδια πρωτεογλυκάνη εκκρίνεται ιδιοσυστατικά από αυτά τα κύτταρα. Τόσο η γλυκοζαμινογλυκανική της σύσταση όσο και η ανασταλτική της δράση έναντι της ενεργοποίησης του συστήματος του συμπληρώματος είναι παρόμοιες με τη SG που εκκρίνεται από τα μυελωματικά κύτταρα. Η συμβολή της SG στον επιθετικό φαινότυπο των καρκινικών κυττάρων επιβεβαιώθηκε με την υπερέκφρασή της σε χαμηλής επιθετικότητας κύτταρα καρκίνου του μαστού. Λειτουργίες όπως ο κυτταρικός πολλαπλασιασμός, η μετανάστευση και η διήθηση των καρκινικών κυττάρων σχετίσθηκαν θετικά με την αυξημένη έκφραση και έκκριση της SG από αυτά τα κύτταρα. Οι επαγωγικές της ιδιότητες καταργήθηκαν με την απαλοιφή των θέσεων πρόσδεσης των γλυκοζαμινογλυκανών από τον πρωτεϊνικό της κορμό. Επιπλέον, διερευνήθηκε το πρωτεολυτικό δυναμικό αυτών των κυττάρων με τη μελέτη της έκφρασης πρωτεολυτικών ενζύμων του εξωκυττάριου χώρου, όπως οι tPA, uPA, MMP-1, MMP-2, MMP-3, MMP-9, MT1-MMP και του αναστολέα των μεταλλοπρωτεϊνασών TIMP-1. Παρουσιάσθηκε ότι η υπερέκφραση του πλήρους μορίου της SG αλλά και της μη γλυκοζυλιωμένης της μορφής οδηγούν στη διαφοροποίηση της έκφρασης και της ενεργότητας των μορίων αυτών με τρόπο που ποικίλει ανάλογα με την κυτταρική πυκνότητα. Παρόλα αυτά, τα δεδομένα που προέκυψαν από τη μελέτη της έκφρασης του uPA και της MT1-MMP συσχέτισαν την αυξημένη τους ενεργότητα με την υπερέκφραση της γλυκοζυλιωμένης μορφής της SG και ανέδειξαν την πιθανή συμβολή τους στην επιθετικότητα των καρκινικών κυττάρων μαστού. Συμπερασματικά, η παρουσία της SG είναι έντονη σε πληθώρα συμπαγών όγκων και καρκινικών κυτταρικών σειρών και φαίνεται να σχετίζεται με το μεταστατικό δυναμικό των κυττάρων. Η συμβολή της στον επιθετικό φαινότυπο των καρκινικών κυττάρων περιλαμβάνει τόσο ενδοκυττάριες όσο και εξωκυττάριες δράσεις που μεσολαβούνται από τη γλυκοζυλιωμένη της μορφή. / Serglycin (SG) is the major proteoglycan of hematopoietic origin cells and contributes to the regulation of several inflammatory proteins. Moreover, SG has a significant role in the biology of Multiple Myeloma; It inhibits the activation of the classical and the lectin pathway of complement system. Enhanced SG expression is correlated with the aggressive phenotype of nasopharyngeal cancer cells. In the present study, the expression of SG in several malignancies was investigated. The strong presence of SG in solid tumors due to its elevated expression either by cancer cells or by inflammatory and stomal cells was revealed. Furthermore, SG elevated expression and secretion was correlated with the high metastatic potential of several cancer cell lines. The expression of the alternatively spliced SG mRNA (variant 2) was identified. This variant lacks exon 2. The role of SG in the biology of aggressive breast cancer cells was studied. SG interacts with significant mediators of actin cytoskeleton reorganization, protein transport and regulation of gene expression. This proteoglycan is constitutively secreted by aggressive breast cancer cells and shares the same glycosaminoglycan (GAG) moieties and inhibitory effects torward complement system activation as the secreted SG by myeloma cells. SG contribution in the aggressive phenotype of cancer cells was studied via the overexpression of the moleclule in the low aggressive breast cancer cells. Cellular functions such as proliferation, migration and invasion of cancer cells were positively correlated with the elevated expression and secretion of SG. These properties were abolished by the deletion of GAG binding sites from SG core protein. Moreover, the proteolytic potential of the overexpressing cells was examined via the expression of ECM degrading molecules, such as tPA, uPA, MMP-1, MMP-2, MMP-3, MMP-9, MT1-MMP, and TIMP-1 MMP inhibitor. Altered expression and activity rates of these enzymes correlated with the overexpression of either the full length or the truncated form of SG in a manner which depends on the cellular density. Interestingly, enhanced MT1-MMP activity followed only the overexpression of the full length molecule indicating the contribution of this MMP in breast cancer cell aggressiveness. The data above revealed the intense presence of SG in several solid tumors and cancer cell lines and the correlation of SG expression with the metastatic potential of cancer cells. Its contribution to cancer cells aggressive phenotype includes both intracellular and extracellular functions which are mediated by the glycanated form of SG.

No description available.

Funcionalmente, a cartilagem da articulação têmporo-mandibular assemelha-se à cartilagem da articulação do joelho por possuírem lubrificação para resistir à fricção e fornecerem proteção às forças mecânicas externas. Entretanto, o efeito das forças de tensão sobre as cartilagens dessas duas articulações ainda permanece obscura. O objetivo desse estudo foi avaliar, in vitro, as alterações metabólicas nos condrócitos extraídos do tecido cartilaginoso do côndilo mandibular e do joelho de suínos, decorrentes da aplicação de forças mecânicas, em relação à síntese de DNA e de proteoglicanos (PTG). Além disso, foi verificada a expressão de colágeno tipo II e de agrecanos no RNAm dos condrócitos dessas duas articulações, tempo-dependente do cultivo celular, utilizando-se a análise quantitativa de PCR em tempo real. Os condrócitos foram submetidos às forças mecânicas de tração de 2 kPa (3% de alongamento), 5 kPa (7% de alongamento) e 10 kPa (12% de alongamento), em uma freqüência de 30 ciclos/min. durante 12 e 24 horas. Os resultados demonstraram que os condrócitos do côndilo mandibular quando submetidos às forças de 2 kPa e de 5 kPa, apresentaram um aumento estatisticamente significativo da síntese de DNA e de PTG, em 12 h. (p < 0,01) e em 24 h. (p < 0,05). Exceto o aumento da síntese de DNA do grupo submetido à força de 5 kPa que durante 24h. não foi estatisticamente significativo (p > 0,05). A força de 10 kPa causou uma diminuição estatisticamente significativa na síntese de DNA e de PTG nos condrócitos do côndilo mandibular, em ambos os tempos de ensaio mecânico (p < 0,01). Por outro lado, os condrócitos do joelho apresentaram um aumento na síntese de DNA e de PTG quando submetidos à todas as magnitudes de força de tração. A força de 5 kPa estimulou um aumento estatisticamente significante das sínteses de DNA e PTG, em 12 h. e 24 h. (p < 0,01). Em 10 kPa, foi observado um incremento estatisticamente significante de DNA em 12 h. (p < 0,01) e em 24 h. (p < 0,05) e de PTG em 24h. (p < 0,01). Foi verificado que os condrócitos do joelho apresentaram uma maior expressão de colágeno tipo II e de agrecanos do que os condrócitos do côndilo mandibular estatisticamente significativo (p < 0,05). A expressão de colágeno tipo II e de agrecanos nos condrócitos do côndilo mandibular foram altamente evidenciados na fase proliferativa e diminuíram progressivamente com a formação de matriz extracelular. Contrariamente, os condrócitos do joelho apresentaram um aumento da expressão de agrecanos no RNAm conforme o amadurecimento do cultivo celular e um aumento expressivo de colágeno tipo II na fase proliferativa, seguida de discreta queda durante a fase da matriz celular. Os condrócitos dos tecidos cartilaginosos do côndilo mandibular e do joelho de suínos demonstraram diferentes mecanismos de resposta às forças mecânicas e de metabolismo celular. / Functionally, the mandibular condylar cartilage is similar to the ankle articular cartilage, both provides lubrication to resist friction and offers protection against external mechanical loading. However, the effect of tension loadings on these two articular cartilages remains unclear. The purpose of this study was to evaluate in vitro, the metabolism of the chondrocytes isolated from the cartilage tissues of porcine mandibular condyle and ankle, in response to the tension mechanical forces, related to the syntheses of DNA and proteoglycan (PTG). It was also verified the expression of mRNA type II collagen and aggrecan on the condrocytes of these two joints on culture time-dependent, using a quantitative real-time PCR analysis. The chondrocytes were submitted to tensile mechanical strains of 2 kPa (3% elongation), 5 kPa (7% elongation) and 10 kPa (12% elongation), with a frequency of 30 cycles/min for 12 and 24 hours. The results showed that the condrocytes from mandibular condyle, when submitted to tension forces of 2 kPa and 5 kPa, demonstrated a statistically significant enhancement of DNA and PTG, in 12 h. (p < 0.01) and in 24 h. (p < 0.05). Except the increase of DNA synthesis of the group submitted to the force of 5 kPa during 24 h. that was not statistically significant (p > 0.05). The force of 10 kPa caused a statistically significant decrease of DNA and PTG syntheses on the condrocytes of mandibular condyle, in both periods of mechanical stimulation (p < 0.01). On the other side, the condrocytes of ankle showed an increase of DNA and PTG syntheses when subjected to all the magnitudes of tension forces. The force of 5 kPa stimulated statistically significant the syntheses of DNA and PTG, in 12 h. and 24 h. (p < 0.01). In 10 kPa, it was observed a statistically significant increment of DNA in 12 h. (p < 0.01) and in 24 h. (p < 0.05) and PTG synthesis in 24 h. (p < 0.01). The condrocytes of ankle showed a statistically significant higher (p < 0.05) expression of collagen type II and aggrecan than the condrocytes of mandibular condyle. The type II collagen and aggrecan mRNA in mandibular condyle were highly expressed in proliferating chondrocytes and decreased progressively in matrix-forming chondrocytes. Conversely, the condrocytes from ankle showed an increase of aggrecan expression on mRNAs with the cell culture maturation, and an increase of type II collagen during the proliferating phase, followed by a slight decrease of this protein during the matrix-forming phase. The chondrocytes from the cartilage tissues of mandibular condyle and ankle showed different mechanisms of response to the mechanical loadings and distinct chondrocytes metabolism.