In periodontitis, there is a disruption in the homeostasis of the oral microbiome by peridontopathogenic bacteria. However, while bacteria is essential for periodontitis to occur, the severity, pattern and progression of the disease is not solely determined by the microbial burden, and in fact has a lot to do with the overwhelming host inflammatory response. The response can vary even in two individuals with similar periodontopathogenic profiles. The host response leads to extracellular matrix (ECM) destruction, loss of attachment, alveolar bone resorption and eventually, edentulism. The host's reaction is orchestrated by proinflammatory cytokines and chemokines and matrix metalloproteinases (MMPs). MMPs are proteolytic enzymes capable of degrading collagen fibers from the extracellular matrix and are the main responsible for tissue damage and gingival recession in periodontitis. As a response to the limitations of the traditional therapies, new agents have been used in preclinical and clinical studies, namely host-modulatory agents, including anti-proteinase agents, anti-inflammatory agents and anti-resorptive agents. Focusing on changing the inflammatory process, as opposed to the microbial insult, can slow down the disease progression, improve clinical outcomes and even prevent tooth loss in severely compromised patients. This work examines the role of pro-inflammatory markers homocysteine in chronic inflammation and periodontitis. Homocysteine (Hcy) is a non-protein amino acid derived from the metabolism of the essential amino acid methionine via methyl group metabolism. Controlling Homocysteine as a potential inductor of MMPs, and hence of tissue destruction, can lead to new adjuvant therapies to improve clinical outcomes and prevent activation of the disease

Thesis (Ph. D.)--Virginia Commonwealth University, 2009. / Prepared for: Dept. of Physiology. Bibliography: leaves 171-206. Also available online via the Internet.

Soft tissue sarcomas (STS) are rare human malignant neoplasms, arising mostly from stem cells within non-skeletal connective tissues. They account for approximately 1% of all human malignancies. Matrix metalloproteinases (MMPs) are enzymes involved in degradation of the extracellular matrix and their expression by cancer cells allows the cells to penetrate basement membranes and tissue matrix, thereby invading and metastasising. The most studied malignant tumours from the perspective of MMP expression and its relationship to malignant behaviour are epithelial-derived carcinomas. MMPs role in invasion and metastasis of sarcomas has been very little investigated. This is in part because of the difficulty in accumulating sufficient tumour tissue to enable statistically relevant analysis of sufficient tumours. The purpose of this thesis was to examine the expression of key MMPs - MMP-2, MMP-7, MMP-9, and MMP-14 and their inhibitors (TIMP-1 and TIMP-2) at the invasive/subcapsular edge of human malignant and benign connective tissue tumours using immunohistochemistry, a technique that allows a very high level of reaction product localisation within tumours. In three different STS types and appropriate benign equivalents, the expression of MMPs -2, -7, -9, and -14 and their inhibitors (TIMPs -1 and -2) were measured using intensity of staining and the percentage area of staining by image analysis. The results were compared between tumour types and against histological grading that is widely used as a prognostic factor. The findings from this research indicated that metalloproteinases were commonly expressed in STS and benign equivalents. There were differences in expression of some benign versus malignant neoplasms of the same group. No uniform pattern of expression of any of MMPs was observed across the tumours, but some of the data, most notably that for expression of MMP-2 and -9 indicate, a role for MMPs in malignant behaviour and some showed (e.g. MMPs -7 and -14) change in expression with the grade of malignant tumours in the same broad category. There is some evidence of an inverse relationship between MMP and appropriate TIMP expression suggesting that a failure of inhibition, as much as increased expression, is a feature of malignancy.

Matrix Metalloproteinase-28 (MMP-28) is the newest and least characterized member of MMP family. To date several potential substrate candidates for MMP-28 have been proposed but no in vivo substrates for this enzyme were confirmed. In the central nervous system (CNS) MMP-28 is believed to be important factor during myelination of the developing nervous system as well as during remyelination that follows neuronal injury. On the other hand, MMP-28 has been found in actively demyelinating lesions in both experimental autoimmune encephalopathy (EAE) and multiple sclerosis patients suggesting its possible role in pathological events associated with autoimmune neurodegenerative processes. In addition, MMP-28 has been linked to modulation of immune response and activation of macrophages which presents another role of this enzyme in autoimmune pathologies. In the study described herein, MMP-28 has been shown to affect myelin composition and appearance, mitochondrial protein content, and vesicular transport proteins. Moreover, the decrease in myelin basic protein quantity observed in healthy MMP-28KO animals affected the myelin staining intensity in various brain regions including corpus callous. Cellular energetic studies did not reveal differences in mitochondrial function in MMP-28KO animals and no difference in reactive oxygen species was observed. In the EAE model, MMP-28 deletion increased the occurrence of atypical form of EAE characterized by increased inflammation of arbor vitae of the brain. In addition, MMP-28 deletion decreased the inflammatory infiltrates present in brains obtained from EAE animals. Lastly, MMP-28 has been shown to affect cellular energetics and activation of bone marrow derived macrophages during the initial stages and after 24 h activation. In addition, MMP-28 deletion increased proinflammatory cytokines and receptors CD86 and iNOS found in M1 polarized macrophages. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2020. / FAU Electronic Theses and Dissertations Collection

No description available.

Matrix metalloproteinases (MMPs) play a significant role in degrading the extracellular matrix in cancer development and metastasis. Overexpression of matrix metalloproteinases in tumour tissues relative to normal tissues has been exploited as a target for peptide-based therapeutics, to improve therapeutic index of currently used agents. The stability of MMP-activated prodrugs in normal tissue or organs is a significant challenge for their success in the clinic. In an in vitro study, the stability of twenty six prodrugs was studied in mouse liver, kidney, lung and tumour homogenates using HPLC and LC/MS. Selected agents were studied in vivo. Each prodrug has a characteristic amino acid sequence with dominant FITC N-terminal end cap. All prodrugs were conjugated to a colchicine derivative (ICT 2552) which is a vascular disrupting agent causing tumour vasculature shutdown and consequently, tumour necrosis. ICT 3146, ICT 3019, ICT 3120 and ICT 3115 prodrugs showed significant stability in normal tissues and considerable activation in certain tumour tissues compared to the lead compound ICT 2588. Also, the selectivity of promising prodrugs to the MMP family was confirmed by using leupeptin (serine, cysteine and threonine protease inhibitor), pepstatin A (aspartate protease inhibitor), phosphoramidon (nepralysin inhibitor), ilomastat (metalloproteinase inhibitor) and BML-P115 (matrix metalloproteinase inhibitor). Moreover, members of the MMP family responsible for cleaving the selected prodrugs were identified using recombinant MMP enzymes. Furthermore, a LC/MS-MS method was developed to specifically detect and quantify MMP-16 protein expression in H460 tumour. MMP- 16 was responsible for the cleavage of ICT 3146 and ICT 3115. Therefore, MMPactivated prodrugs could be a useful therapeutic approach to avoid off-site toxicities of currently used anti-tumour agents.

Diss. (sammanfattning) Stockholm : Karol. inst., 2006. / Härtill 4 uppsatser.

Matrix metalloproteinases (MMPs) play a significant role in degrading the extra- cellular matrix in cancer development and metastasis. Overexpression of matrix metalloproteinases in tumour tissues relative to normal tissues has been exploited as a target for peptide-based therapeutics, to improve therapeutic index of currently used agents. The stability of MMP-activated prodrugs in normal tissue or organs is a significant challenge for their success in the clinic. In an in vitro study, the stability of twenty six prodrugs was studied in mouse liver, kidney, lung and tumour homogenates using HPLC and LC/MS. Selected agents were studied in vivo. Each prodrug has a characteristic amino acid sequence with dominant FITC N-terminal end cap. All prodrugs were conjugated to a colchicine derivative (ICT 2552) which is a vascular disrupting agent causing tumour vasculature shutdown and consequently, tumour necrosis. ICT 3146, ICT 3019, ICT 3120 and ICT 3115 prodrugs showed significant stability in normal tissues and considerable activation in certain tumour tissues compared to the lead compound ICT 2588. Also, the selectivity of promising prodrugs to the MMP family was confirmed by using leupeptin (serine, cysteine and threonine protease inhibitor), pepstatin A (aspartate protease inhibitor), phosphoramidon (nepralysin inhibitor), ilomastat (metalloproteinase inhibitor) and BML-P115 (matrix metalloproteinase inhibitor). Moreover, members of the MMP family responsible for cleaving the selected prodrugs were identified using recombinant MMP enzymes. Furthermore, a LC/MS-MS method was developed to specifically detect and quantify MMP-16 protein expression in H460 tumour. MMP- 16 was responsible for the cleavage of ICT 3146 and ICT 3115. Therefore, MMP-activated prodrugs could be a useful therapeutic approach to avoid off-site toxicities of currently used anti-tumour agents. / The full text will be available at the end of the extended embargo: 5th March 2027

Orientador: Sandra Helena Penha de Oliveira / Banca: Marília Afonso Rabelo Buzalaf / Banca: Carlos Ferreira dos Santos / Resumo: O declínio mundial da cárie dentária é atribuído ao uso abrangente do flúor. Embora esse elemento seja capaz de proteger os dentes, seu uso excessivo pode levar a uma ação citotóxica causando a inibição do crescimento celular, da síntese de proteínas e até mesmo a morte celular. O primeiro objetivo deste estudo foi investigar a concentração ideal do NaF (NaF) capaz de ativar os fibroblastos gengivais de camundongos sem induzir morte celular. Observou-se que, nesses fibroblastos, a concentração de 40 μg F/mL induziu morte celular de 62,6 %. Na concentração de 20 μg F/mL a morte celular foi de apenas 22,1%. Com base nesses resultados, optou-se por utilizar a concentração de 20 μg F/mL como dose máxima para investigar os mecanismos envolvidos na ativação dos fibroblastos gengivais. Dessa forma, avaliou-se a capacidade do NaF induzir a expressão de MMP-2 e MMP-9 pelos fibroblastos gengivais de camundongos na presença ou ausência de LPS, assim como a produção da quimiocina CCL-3/MIP-1α e óxido nítrico. Avaliou-se também a participação das vias de sinalização intracelular p44/42, p38, PI3K e NF-кB envolvidas durante essa ativação, por meio da utilização dos respectivos inibidores PD98059 (50 μM), SB202190 (10 μM), LY294002 (30 μM) e dexametasona (10 μM). Observou-se que o NaF foi capaz de estimular os fibroblastos gengivais a expressarem MMP-9, mas não MMP-2, na concentração de 20 μg F/mL com pico máximo 6 horas após, retornando aos níveis normais 24 horas após. A produção da quimiocina CCL3/MIP-1α pelos fibroblastos estimulados pelo NaF também foi observada com a concentração de 20 μg F/mL com pico máximo 6 horas após estímulo. Na presença de LPS, observou-se uma potenciação da expressão de MMP-9 e produção de CCL3/MIP-1α na concentração de 20 μg F/mL, 6 horas após. / Abstract: The worldwide decline of the dental caries is attributed to the widespread use of fluoride. Although this element is capable of protecting the teeth, its excessive use, can lead to a cytotoxic action, causing an inhibition of the cell growth, of the protein synthesis and even the cellular death. Based on these results, we have chosen to use a concentration of 20 μ g F/mL as maximum concentration to investigate the mechanisms involved in the activation of the gingival fibroblasts. It was observed that, on those fibroblasts, the concentration of 40 μg F/mL has resulted in a death cellular index of 62.6%. In the concentration of 20 μg F/mL the cellular death was of 22.1% only. Based on these results, the concentration of 20 μg F/mL has been chosen as maximum concentration to investigate the mechanisms involved in the activation of the gingival fibroblasts. Later, the ability of NaF to induce the expression of MMP-2 and MMP-9 in gingival fibroblasts of mice in the presence or absence of LPS has been assessed, as well as the production of chemokine CCL-3/MIP-1a and nitric oxide. It also evaluated the participation of intracellular signaling pathways p44/42, p38, PI3K e NF-kB involved in this activation, through inhibitors PD98059 (50 μM), SB202190 (10 μM), LY294002 (30 μM) e dexamethasone (10 μM). It was observed that the NaF was capable to stimulate the gingival fibroblasts to express MMP-9, at the concentration of 20 μgF/mL with maximum peak 6 hours after, returning to normal levels 24 hours after. The expression of MMP-2 was not observed. The production of chemokine CCL3/MIP-1α was also observed with the concentration of 20 μgF/mL with maximum peak 6 hours after the stimulation. In the presence of LPS, it was observed an intensification in the expression of MMP-9 and also in the production of CCL3/MIP-1α at the concentration of 20 μgF/mL, 6 hours later. / Mestre

Malignant brain tumors are among the deadliest of human cancers. Despit recent advancements in conventional therapies, glioblastomas remain incurable, largel y due to their ability to invade surrounding tissue. Matrix metalloproteinases are thought to contribute to the invaseive phenotype of human gliomas. Absent in normal brain, matrix metalloproteinase-1 (MMP-1) has been shown to be present in gliomas, and in particular in glioblastoma multiforme (GBM). To begin to examine the role of MMP-1 in these tumore, two human glioma cell lines were stably transfected with MMP-1 cDNA. Confirmation of MMP-1 over-expression in these cells was achieved through real-time PCR and Western blot analysis. The functional consequences of MMP-1 over-expression were analyzed using a collagen type-I invasion assay along with clonogenic and ATP viability assays. Data presented demonstrate that MMP-1 over-expressing cells were more invasive in both cell types and interestingly more clonogenic in on of the glioma cell lines, supporting a possible role for MMP-1 in glioma growth and invasion.