973 resultados para Matrix Metalloproteinases


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Rodrigues SF, Tran ED, Fortes ZB, Schmid-Schonbein GW. Matrix metalloproteinases cleave the beta(2)-adrenergic receptor in spontaneously hypertensive rats. Am J Physiol Heart Circ Physiol 299: H25-H35, 2010. First published April 9, 2010; doi:10.1152/ajpheart.00620.2009.-We recently observed the enhanced serine and matrix metalloproteinase (MMP) activity in the spontaneously hypertensive rat (SHR) compared with its normotensive Wistar-Kyoto (WKY) rat and the cleavage of membrane receptors in the SHR by MMPs. We demonstrate in vivo that MMP-7 and MMP-9 injection leads to a vasoconstrictor response in microvessels of rats that is blocked by a specific MMP inhibitor (GM-6001, 1 mu M). Multiple pathways may be responsible. Since the beta(2)-adrenergic receptor (beta(2)-AR) is susceptible to the action of endogenous MMPs, we hypothesize that MMPs in the plasma of SHRs are able to cleave the extracellular domain of the beta(2)-AR. SHR arterioles respond in an attenuated fashion to beta(2)-AR agonists and antagonists. Aorta and heart muscle of control Wistar rats were exposed for 24 h (37 C) to fresh plasma of male Wistar and WKY rats and SHRs with and without doxycycline (30 mu M) and EDTA (10 mM) to reduce MMP activity. The density of extracellular and intracellular domains of beta(2)-AR was determined by immunohistochemistry. The density of the extracellular domain of beta(2)-AR is reduced in aortic endothelial cells and cardiac microvessels of SHRs compared with that of WKY or Wistar rats. Treatment of the aorta and the heart of control Wistar rats with plasma from SHRs, but not from WKY rats, reduced the number of extracellular domains, but not intracellular domains, of beta(2)-AR in aortic endothelial cells and cardiac microvessels. MMP inhibitors (EDTA and doxycycline) prevented the cleavage of the extracellular domain. Thus MMPs may contribute to the reduced density of the extracellular domain of beta(2)-AR in blood vessels and to the increased arteriolar tone of SHRs compared with normotensive rats.

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P>Matrix metalloproteinases (MMPs) modulate extracellular matrix turnover, inflammation and immunity. We studied MMP-9 and MMP-2 in experimental paracoccidioidomycosis. At 15 and 120 days after infection (DAI) with virulent Paracoccidioides brasiliensis, MMP-9 was positive by immunohistochemistry in multinucleated giant cells, in mononuclear cells with macrophage and lymphocyte morphologies and also in fungal cells in the lesions of susceptible and resistant mice. Using gelatin zymography, pro- and active MMP-9 and active MMP-2 were detected in all infected mice, but not in controls. Gelatinolytic activity was not observed in P. brasiliensis extracts. Semiquantitative analysis of gelatinolytic activities revealed weak or absent MMP-2 and strong MMP-9 activity in both mouse strains at 15 DAI, declining at 120 DAI. Avirulent P. brasiliensis-infected mice had residual lesions with MMP-9-positive pseudoxantomatous macrophages, but no gelatinase activity at 120 DAI. Our findings demonstrate the induction of MMPs, particularly MMP-9, in experimental paracoccidioidomycosis, suggesting a possible influence in the pattern of granulomas and in fungal dissemination.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Este estudo teve como objetivo avaliar a expressão das metaloproteinases 2 (MMP-2) e 9 (MMP-9) em próstatas caninas normais e com desordens proliferativas, verificando o papel dessas enzimas na remodelação da matriz extracelular (MEC) e no processo de invasão tecidual. Um total de 355 amostras prostáticas foram obtidas, sendo 36 (10,1%) normais, 46 (13,0%) com hiperplasia prostática benigna (HPB), 128 (36,1%) com atrofia inflamatória proliferativa (PIA), 74 (20,8%) com neoplasia intraepitelial prostática (PIN) e 71 (20,0%) com carcinoma prostático (CP). Houve diferença de imunomarcação citoplasmática para MMP-2 e MMP-9 entre o epitélio acinar e o estroma periacinar, quanto aos diferentes diagnósticos. Observou-se correlação entre a expressão de MMP-2 e MMP-9 em relação ao número de células marcadas no epitélio acinar e estroma periacinar, bem como para a intensidade de marcação das células estromais periacinares em próstatas caninas com PIA. Conclui-se que há variação na expressão de MMP-2 e MMP-9 em próstatas caninas de acordo com a lesão, com menor expressão em próstatas caninas normais e com HPB, e maior naquelas com PIA, PIN e CP. Ainda, o microambiente inflamatório na PIA influencia a atividade de ambas as enzimas.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Angiotensin-converting enzyme inhibitors (ACEi) may downregulate matrix metalloproteinases (MMPs). We examined whether enalapril affects MMP-2, MMP-8, and MMP-9 levels and activity, and their endogenous inhibitors (tissue inhibitors of MMPs, TIMP-1 and TIMP-2) levels in hypertensive patients. Moreover, we assessed the effects of enalaprilat on MMP-9 and TIMP-1 secretion by human endothelial cells (HUVECs). Thirty-eight hypertensive patients received enalapril for 8 weeks and were compared with thirty-eight normotensive controls. Blood samples were collected at baseline and after treatment. Plasma ACE activity was determined by a fluorimetric assay. Plasma MMP-2, MMP-8, MMP-9, TIMP-1, and TIMP-2 were measured by ELISA and gelatin zymography. A fluorogenic peptide cleavage assay was used to measure MMP activity. HUVECs cells were stimulated by phorbol-12-myristate-13-acetate (PMA) and the effects of enalaprilat (10(-10) to 10(-6) M) on MMP-9 and TIMP-1 levels were determined. Enalapril decreased blood pressure and ACE activity in hypertensive patients (P < 0.05), but had no effects on plasma MMP-2, MMP-8, MMP-9, TIMP-1, and TIMP-2 levels, or MMP activity. Enalaprilat had no effects on PMA-induced increases in MMP-9 and TIMP-1 secretion by HUVECs or on MMP activity. We show consistent evidence, both in vivo and in vitro, that enalapril does not affect MMPs and TIMPs levels in hypertensive patients.

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Rear-fanged and aglyphous snakes are usually considered not dangerous to humans because of their limited capacity of injecting venom. Therefore, only a few studies have been dedicated to characterizing the venom of the largest parcel of snake fauna. Here, we investigated the venom proteome of the rear-fanged snake Thamnodynastes strigatus, in combination with a transcriptomic evaluation of the venom gland. About 60% of all transcripts code for putative venom components. A striking finding is that the most abundant type of transcript (similar to 47%) and also the major protein type in the venom correspond to a new kind of matrix metalloproteinase (MMP) that is unrelated to the classical snake venom metalloproteinases found in all snake families. These enzymes were recently suggested as possible venom components, and we show here that they are proteolytically active and probably recruited to venom from a MMP-9 ancestor. Other unusual proteins were suggested to be venom components: a protein related to lactadherin and an EGF repeat-containing transcript. Despite these unusual molecules, seven toxin classes commonly found in typical venomous snakes are also present in the venom. These results support the evidence that the arsenals of these snakes are very diverse and harbor new types of biologically important molecules.