No description available.

Proteases play a key role in the cascade of tumor-associated proteolysis leading to extracellular matrix degradation, stromal invasion and blood vessel recruitment and inroad. Protease systems are widely described as implicated in the formation of new blood vessels. Until now, only few datas are available concerning their role in lymphangiogenesis. We successfully transposed the aorta ring assay to a mouse lymphatic thoracic duct assay. By immunochemistry and transmission electron microscopy, we characterized the outgrowing cells as being lymphatic cells that organize into microvessels containing a lumen and that conserved lymphatic endothelial cell features. This quantifiable model responds to several well-known lymphangiogenic factors as the VEGF-C but not to specific angiogenic factors. This model is so suitable to screen growth factors and inhibitors as well as conditioned media. Plasminogen activator inhibitor-1 is a component of the plasminogen cascade and, though it was critical for angiogenesis, it comes out that it is dispensable for lymphatic outgrowth. In sharp contrast, synthetic and physiological inhibitors of matrix metalloproteases inhibit lymphangiogenesis, and thoracic duct rings derived from MMP-2- but not MMP-9-deficient mice showed an impaired lymphatic cell outgrowth. These data identify MMP2 as an important player in lymphangiogenesis and was confirmed by an in vivo experiments. Proteases are thus also implicated in lymphangiogenesis and the lymphatic ring assay seems to be helpful to discover novel genes and mechanisms that underly the lymphangiogenesis process, including by comparing with angiogenesis in a similar system.

Damage to cardiac contractile proteins such as myosin light chain 1 (MLC1), during oxidative stress is mediated by reactive oxygen species such as peroxynitrite (ONOO-), resulting in impairment of cardiac systolic function. The purpose of this study is to investigate the effects of the increased level of ONOO- on MLC1 degradation by the proteolytic enzyme matrix metalloproteinase-2 (MMP-2) during oxidative stress which ultimately decreases cardiac function.<p> In the present study two distinct models were utilized to demonstrate the mechanism by which MLC1 is modified by ONOO- and how these post-translational modifications lead to its increased degradation by MMP-2. In a model of newborn hypoxia-reoxygenation in piglets we demonstrated that ONOO--induced nitration and nitrosylation of tyrosine and cysteine residues of MLC1 increase its degradation by MMP-2. Furthermore, we found nitration of a tyrosine residue located adjacent to the cleavage site for MMP-2. We verified these results by using a model of isolated rat heart myocytes to determine that the same mechanism responsible for cardiac dysfunction in newborn piglets occurs in isolated myocytes and that the MMP-2 involved in degradation of MLC1 is located within the myocytes. Moreover, we were able to determine that this mechanism occurs during ischemia itself before the onset of reperfusion. Furthermore, we have found that pharmacological intervention aimed at inhibition of MLC1 nitration/nitrosylation during ischemia by the ONOO- scavenger FeTPPS (5,10,15,20-tetrakis-[4-sulfonatophenyl]-porphyrinato-iron[III]), or inhition of MMP-2 activity with phenanthroline, provides an effective protection of cardiomyocyte contractility. The work presented here provides new evidence on the mechanisms of regulation of contractile proteins during the development of contractile dysfunction.

Damage to cardiac contractile proteins such as myosin light chain 1 (MLC1), during oxidative stress is mediated by reactive oxygen species such as peroxynitrite (ONOO-), resulting in impairment of cardiac systolic function. The purpose of this study is to investigate the effects of the increased level of ONOO- on MLC1 degradation by the proteolytic enzyme matrix metalloproteinase-2 (MMP-2) during oxidative stress which ultimately decreases cardiac function.<p> In the present study two distinct models were utilized to demonstrate the mechanism by which MLC1 is modified by ONOO- and how these post-translational modifications lead to its increased degradation by MMP-2. In a model of newborn hypoxia-reoxygenation in piglets we demonstrated that ONOO--induced nitration and nitrosylation of tyrosine and cysteine residues of MLC1 increase its degradation by MMP-2. Furthermore, we found nitration of a tyrosine residue located adjacent to the cleavage site for MMP-2. We verified these results by using a model of isolated rat heart myocytes to determine that the same mechanism responsible for cardiac dysfunction in newborn piglets occurs in isolated myocytes and that the MMP-2 involved in degradation of MLC1 is located within the myocytes. Moreover, we were able to determine that this mechanism occurs during ischemia itself before the onset of reperfusion. Furthermore, we have found that pharmacological intervention aimed at inhibition of MLC1 nitration/nitrosylation during ischemia by the ONOO- scavenger FeTPPS (5,10,15,20-tetrakis-[4-sulfonatophenyl]-porphyrinato-iron[III]), or inhition of MMP-2 activity with phenanthroline, provides an effective protection of cardiomyocyte contractility. The work presented here provides new evidence on the mechanisms of regulation of contractile proteins during the development of contractile dysfunction.

No description available.

The objective of the presented research is to examine the relationship between the cellular microenvironment and biochemical response of metastatic cells. Clinically recognized as a trait of cancer progression, the cellular microenvironment can have variable and distinct mechanical properties that are processed via cellular mechanosensing, resulting in a cellular biochemical response. A range of studies investigating the interactions between the cellular micromechanical environment and the cell's molecular response during disease progression have been made, yet remain absent of quantitative characterization of many of these coordinated responses. The fundamental inquiry that drives the following research attempts to elucidate how a cell perceives the physical microenvironment and converts that signal to a biochemical response. With the goal of providing insight to such responses, the presented research seeks to elucidate the following questions: (1) What are the integrated effects of ECM stiffness, ECM architecture, and breast cancer cell metastatic potential on cell migration? (2) How does endogenous tissue transglutaminase (tTG) cross-linking of the ECM scaffold effect ECM mechanical properties? (3) How does the architecture and stiffness of the extracellular matrix (ECM) effect the systems-level cellular migration and signaling response? (4) What are the integrated effects of ECM architecture and the targeted knockdown of integrin [beta]1 and MT1-MMP on cellular metastatic potential? The presented research utilizes an interdisciplinary approach, integrating experimental mechanics, biochemical analysis, cellular biology techniques, covalent chemistry, and various microscopy techniques, to investigate these events. In short, cancerous cells are cultured atop or within synthetic collagen type I ECMs of varying mechanical stiffness and structure. These cells are subsequently analyzed by molecular analysis and immunoassays, including quantitative PCR, Western blotting, and gelatin zymography, to acquire measures of the cellular response to perturbations of micromechanical environment. Time-lapse microscopy experiments and subsequent image analyses enable observations of cellular migratory potential through synthetic ECMs. Results indicate that cooperative synergy between ECM properties, cell-matrix adhesion, and pericellular proteolysis drive cell migratory potential of highly invasive tumorigenic cell populations. Collectively, these findings contribute to the cancer biology and mechanobiology fields by systematically extending current insights of matrix mechanics, cellular signaling, and cellular migratory potential in cancer. / text

O osso é um tipo especializado de tecido com alto teor mineral e desempenha variadas funções no organismo, como a reserva de cálcio, proteção de estruturas vitais e alavanca para a movimentação dos musculos. Constantemente o osso passa por processos de remodelação, o que mantém sua estrutura funcional e repara pequenas fraturas que ocorrem normalmente devido ao estresse do uso contínuo. O sistema de reparo funciona em perfeita sincronia mediante células que produzem os componentes ésseos e células que os reabsorvem permitindo a organização do tecido. Esse sistema de manuteção depende da interação entre estas células bem como dos sinais enviados por mediadores e moduladores. Varias proteínas funcionam como indutores de formação óssea, mas também no sentido de facilitar essa reconstrução. Dentre estas proteínas se encontram as BMPs, que possuem grande potencial osteoindutor, e MMPs, que atuam em diversas fases da construção e manutenção deste tecido. Particularmente a BMP-2 tem mostrado um potencial significativo em termos de indução e sua forma recombinante a rhBMP-2, produzida por engenharia recombinante, foi liberada para comercialização e utilizacao clínica. Quanto às MMPs, há importante função das MMP-2 e MMP-9 neste tecido. A primeira estruturando a matriz e modulando o processo de reabsorção nos processos inflamatórios inerentes ao reparo; a segunda atuando desde fases iniciais às tardias, produzida principalmente por osteoclastos e utilizada na remodelação do osso novo. Porém, esta capacidade de reparo do osso é limitada e defeitos ósseos de grande extensão exigem muito do organismo, podendo levar a um reparo que não se estrutura devidamente. Assim, várias técnicas foram propostas para estimular o desenvolvimento ósseo e a utilizacao de enxertos se mostrou eficaz para fornecer um arcabouço de crescimento, facilitando a implantacao do osso neofomado e protegendo o leito do defeito durante todo o extenso período de recuperação. O presente estudo enfocou três diferentes tipos de enxerto ósseo (autólogo, homólogo e heterólogo) e suas associações com a proteína rhBMP-2, verificando sob o aspecto bioquímico a relação de cada um com a quantidade de MMP-2 e MMP-9 em dois tempos de reparo diferentes. De maneira geral, verificou-se que no primeiro momento há maior produção de MMP-2 e os níveis de MMP-9 se mantém de forma relativamente constante nos dois tempos cirúrgicos. O enxerto autólogo apresenta melhores resultados, seguido dos obtidos no enxerto homólogo e heterólogo respectivamente, entretanto a adição de rhBMP-2 a estes enxertos não parece influenciar nos níveis de MMP-2 e MMP-9 nos dois períodos. A dosagem de cálcio revelou que se apresentavam mais mineralizados os grupos de enxerto autólogo e homólogo, os demais grupos além de apresentar menores niveis de cálcio, ainda decresceram nestes níveis no segundo período do experimento. / Bone is a special tissue with a high mineral content and performs various functions in the body, such as calcium reserves, protection of vital structures and muscles lever during the movement. Bone constantly undergoes remodeling processes, which keeps its functional structure and repair small fractures that commonly occur due to the stress of continuous use. The repair system works perfectly synchronized by the cells that produce bone components and resorbing cells, allowing the perfect tissue organization. This maintenance system depends on the interaction between these cells and the signals sent by mediators and modulators. Several proteins operate to induce bone formation, but also to facilitate the reconstruction. Among these proteins are the BMPs, which have great osteoinductive potential, and MMPs that act at different stages of construction and maintenance of this tissue. Particularly BMP-2 has shown significant potential in terms of induction and its recombinant form, rhBMP-2, produced by recombinant engineering, has been released for clinical use and commercialization. In relation to MMPs, there are important functions of MMP-2 and MMP-9 in this tissue. First, structuring the matrix and modulating the resorption during inflammatory processes inherent to repair; second, acting at early to later stages, produced mainly by osteoclasts and used during bone remodeling. However, this repair capacity is limited and large bone defects require a lot of strength of the body, may leading to a bone repair not well structured. Thus, several proposed techniques to stimulate the development and use of bone grafts were effective to provide a framework for growth, facilitating the implementation of new bone and protecting the defect bed throughout the extended recovery period. This study focused on three different types of bone graft (autologous, homologous and heterologous) and their association with rhBMP-2 protein, evaluating the biochemical aspects according to the amount of MMP-2 and MMP-9 in two different periods of time. In general, it was found that firstly, there is an increased production of MMP-2, and MMP-9 levels remain relatively constant in both considered periods of time. The autologous graft presented the best results followed by homologous and heterologous, respectively; however the addition of rhBMP-2 in these grafts did not seem to influence the MMP-2 and MMP-9 levels, in both periods of time. The calcium dosage revealed more mineralization at the autologous and homologous groups, the other groups, besides having lower calcium levels, decreased these levels at the second period of this experiment.

Introdução: O câncer de próstata (CaP) é o tumor mais freqüente do homem no Brasil tendo sido estimados mais de 52.350 novos casos em 2010, sendo a segunda causa de óbito por câncer em homens. O prognóstico depende fundamentalmente dos níveis séricos de Prostatic Specific Antigen (PSA) estádio tumoral (TNM) e grau de diferenciação histológica (Gleason). Porém esses têm sido insuficientes na definição do prognóstico da neoplasia. Por isso pesquisas têm sido direcionadas para a identificação de alterações moleculares que possam prever o potencial de agressividade do câncer de próstata. Metaloproteinases da matriz (MMP) são proteínas pertencentes a uma família de aproximadamente 30 enzimas proteolíticas ou endoproteinases que degradam vários componentes da matriz extracelular. A detecção de sua expressão tem sido estudada como marcador sensível e específico de vários tumores, principalmente as MMP pertencentes ao grupo das gelatinases MMP-2 e MMP-9. Objetivo: o objetivo deste nosso trabalho foi avaliarmos pela técnica de qRT-PCR e imuno-histoquímica os níveis de expressão dos genes das MMP pertencentes ao grupo das gelatinases, MMP-2 e MMP-9, bem como outros sabidamente envolvidos em suas vias de ativação (MMP-14, IL-8) e inibição (TIMP-1, TIMP-2, RECK e TGF-) no câncer localizado de próstata. Material e Métodos: O estudo consistiu na análise de espécimes de 79 pacientes com câncer da próstata submetidos a prostatectomia radical entre setembro de 1997 e fevereiro de 2000. Esses oito genes foram então testados quanto a seu valor prognóstico no câncer da próstata através da técnica de reação em cadeia da polimerase quantitativa com transcriptase reversa (qRT-PCR). Análise proteica foi feita a partir de 40 pacientes deste pool. O grupo controle foi composto de tecido de 11 pacientes com hiperplasia benigna da próstata (HPB) tratados cirurgicamente com prostatectomia retropúbica. Resultados: MMP-9 esteve superexpressa e MMP-2, TIMP-1, TIMP-2, MMP 14, IL-8, TGF- e RECK se mostraram subexpressos em tecido representativo de CaP quando comparado com HPB. A análise dos níveis de expressão dos genes com o escore de Gleason, mostrou que MMP-2 e TIMP-2 mesmo mantendo-se subexpressos, tiveram uma expressão maior entre os pacientes que apresentavam Gleason 7 (p=0,04 e p=0,02 respectivamente). De acordo com o valor de PSA préoperatório, encontramos diferenças na expressão de MMP-9. Pacientes que apresentavam um PSA pré-operatório 10 ng/mL possuíam uma mediana de expressão maior que aqueles cujo PSA pré-operatório <10 ng/mL com medianas de expressão de 5,62 e 2,76 respectivamente (p=0,033). Não encontramos diferenças estatísticas entre pacientes que apresentavam ou não recidiva bioquímica quanto a expressão dos 8 genes estudados. Porém o gene da MMP-9 apresentou uma diferença estatística marginal apresentando uma mediana de expressão de 6,29x nos pacientes que apresentaram recidiva bioquímica e de 3,25 nos pacientes que não apresentaram recidiva bioquímica (p=0,090). De acordo com a expressão proteica, encontramos uma maior positividade em MMP-9, MMP-2, TGF-, IL-8 e MMP-14. De acordo com os fatores prognósticos encontramos associação de TIMP-1 com recidiva bioquímica. Conclusão: Encontramos uma superexpressão de MMP-9 e uma subexpressão de MMP-2, TIMP-1, TIMP-2, MMP-14, RECK, IL-8 e TGF- no CaP. Considerando os fatores prognósticos encontramos que aumentados níveis de expressão do gene da MMP-9 associou-se a aumentados níveis de PSA, e mostrou uma tendência de associação com recidiva bioquímica. De acordo com a expressão proteica encontramos que a ausência de TIMP-1 pode ser um indicativo de recidiva bioquímica / Introduction: Currently, Prostate cancer (PCa) is the most common tumor in men in Brazil. It was estimated that more than 52,350 new cases were diagnosed in 2010, being the second cause of death by cancer in man. The prognosis depends mainly on Prostate Specific Antigen (PSA) serum levels, tumor stage (TNM) and histological grade (Gleason), but these parameters, even combined, are insufficient to define the correct prognosis of PCa. Therefore research has been directed towards the identification of molecular alterations that may predict potential aggressiveness of PCa. Matrix metalloproteinases (MMPs) are proteins that belong to a family of about 30 proteolytic enzymes that degrade various components of the extracellular matrix. The analysis of MMPs expression has been studied as a sensitive and specific marker of prognosis of several tumors, and special attention was focused in the group of gelatinases, MMP-2 and MMP-9.Objective: The aim of this study was to evaluate the expression levels of MMP-2 and MMP-9 genes and proteins by quantitative real-time polymerase chain reaction (qRT-PCR) and immunohistochemistry in localized PCa. We also evaluated the expression of genes that are involved in the control of MMP-2 and MMP as activators (MMP- 14, IL-8) or inhibitors (TIMP-1, TIMP-2, RECK and TGF-).Materials and Methods: The casuistic consisted of 79 surgical specimens from patients with localized PCa who underwent radical prostatectomy between September 1997 and February 2000. The control group was composed of specimens from 11 patients with benign prostatic hyperplasia (BPH) treated surgically with retropubic prostatectomy. The results of the 8 genes expression, through qRTPCR and immunohistochemistry, were correlated to the diagnosis and prognosis of PCa. The protein expression analysis was carried out in 40 patients of the casuistic. Results: The MMP-9 was overexpressed, while MMP-2, TIMP-1, TIMP-2, MMP-14, RECK, IL-8, and TGF- were underexpressed in malignant prostate tissue compared to BPH. Patients with Gleason7 had higher expression of MMP-2 and TIMP-2 (p=0.04, p=0.02 respectively). According to the preoperative PSA value, we found that patients with preoperative PSA10 ng/mL had a median of expression of 5.62 compared to 2.76 when PSA<10 ng/mL (p=0.033). There were no statistical differences between expression of the eight genes and biochemical recurrence during follow up. However, the higher MMP-9 expression was marginally associated with recurrence, the median was of 6.29 in recurrence patients compared to 3.25 in those without recurrence (p=0.090). Regarding the protein expression, we found a higher positivity of MMP-9, MMP-2, TGF-, IL-8 e MMP-14 expression in PCa, and a correlation between the lack of TIMP-1 and tumor recurrence. Conclusion: MMP-9 is overexpressed while MMP-2, TIMP-1, TIMP-2, MMP-14, RECK, TGF- and IL-8 are underexpressed in CaP. According to the prognostic factors, we observed that increased level of MMP-9 was associated with pre-surgical PSA10 ng/mL. Also there was a tendency of association between higher MMP- 9 expression and biochemical recurrence. Overexpression of MMP-9 can be explained by the underexpression of their major inhibitors TIMP-1 and RECK. According to protein expression we found that absence of TIMP-1 is correlated with biochemical recurrence in the PCa

Arsenic (As) exposure is associated with cancer, lung and cardiovascular disease, yet the mechanisms involved are not clearly understood. Elevated matrix metalloproteinase-9 (MMP-9) levels are also associated with these diseases, as well as with exposure to water As. Our objective was to evaluate the effects of dietary components of inorganic As (iAs) intake on serum MMP-9 concentration at differing levels of tap water As. In a cross-sectional study of 214 adults, dietary iAs intake was estimated from 24-h dietary recall interviews using published iAs residue data; drinking and cooking water As intake from water samples and consumption data. Aggregate iAs intake (food plus water) was associated with elevated serum MMP-9 in mixed model regression, with and without adjustment for covariates. In models stratified by tap water As, aggregate intake was a significant positive predictor of serum MMP-9 in subjects exposed to water As≤10 μg/l. Inorganic As from food alone was associated with serum MMP-9 in subjects exposed to tap water As≤3 μg/l. Exposure to iAs from food and water combined, in areas where tap water As concentration is ≤10 μg/l, may contribute to As-induced changes in a biomarker associated with toxicity.

No description available.