Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.7.48 (transcriptase)
 9,479 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We report on the effect of prolonged hyperglycaemic (11 and 30 mM D-glucose) culture conditions on human mesangial cell matrix metalloproteinases (MMPs), plasminogen activators and their inhibitors. The results indicate that hyperglycaemic conditions modulate the potential proteolytic activity of the enzymes secreted by confluent cultures of these cells. Gelatinase A (MMP-2) activity was always higher in cultures maintained under hyperglycaemic than under normoglycaemic conditions (4 mM D-glucose). In contrast, gelatinase B (MMP-9) activity was decreased under the same conditions. Matrilysin (MMP-7) activity was decreased by up to 100% under hyperglycaemic conditions. Reverse transcriptase-PCR and Western-blotting analyses indicate that in all cases both the transcripts and the protein level were correlated with enzymic activity. One tissue inhibitor of metalloproteinases, TIMP-2, was barely detectable under hyperglycaemic conditions (30 mM D-glucose). In contrast, TIMP-1 increased during the initial 2 weeks of culture in hyperglycaemic conditions and remained elevated to the end of the experiment (4 weeks). Under normoglycaemic conditions TIMP-1 decreased after 2 weeks of culture. Hyperglycaemic conditions also decreased markedly the activity of tissue plasminogen activator (t-PA). This seemed to be due to increased synthesis of its inhibitor, plasminogen activator inhibitor 1, under these conditions rather than to decreased expression of the t-PA enzyme.
 ...
PMID:Modulation of neutral protease expression in human mesangial cells by hyperglycaemic culture. 900 62

The two matrix metalloproteinases (MMPs) Mr 72,000 type IV collagenase (MMP-2, gelatinase A) and Mr 92,000 type IV collagenase (MMP-9, gelatinase B) play key roles in tissue remodeling and tumor invasion by digestion of extracellular matrix barriers. We have investigated the production of these two enzymes as well as the membrane-type MMP (MT1-MMP) and the tissue inhibitors of metalloproteinases (TIMPs) TIMP-1 and TIMP-2 in the bone marrow mononuclear cells (BM-MNCs) of patients with acute myeloid leukemia (AML; n = 24), chronic myeloid leukemia (CML; n = 17), myelodysplastic syndromes (MDS; n = 8), and healthy donors (n = 5). Zymographic analysis of BM-MNC-conditioned medium showed that a Mr 92,000 gelatinolytic activity, identified as MMP-9 by Western blotting, was constitutively released from cells of all patients and healthy individuals examined in this study. In contrast, MMP-2 secretion was found to be absent in all samples from healthy donors but present in 8 of 11 (73%) of the samples from patients with primary AML, 7 of 8 (88%) with secondary AML, and only 1 of 5 (20%) cases with AML in remission, indicating MMP-2 to be produced by the leukemic blasts. MMP-2 release was not detected in CML cell-conditioned medium with the exception of two cases, both patients either being in or preceding blast crisis. In MDS, MMP-2 was found in three of eight (38%) of the patients, two of them undergoing progression of disease within 12 months. Quantitative Northern blot analysis in freshly isolated BM-MNCs showed a relatively low constitutive expression of TIMP-1 in all samples, whereas MMP-9 gene transcription was higher in healthy donors and CML samples, than in AML and MDS. Reverse transcriptase-PCR analysis revealed the presence of TIMP-2 mRNA in the majority of MMP-2-releasing BM-MNCs. MT1-MMP expression was present in most samples of patients with MDS or AML but absent in those with secondary AML and CML. Thus, we have shown that BM-MNCs continuously produce MMP-9 and TIMP-1 and demonstrated that leukemic blast cells additionally secrete MMP-2 representing a potential marker for dissemination in myeloproliferative malignancies.
 ...
PMID:Matrix metalloproteinase production by bone marrow mononuclear cells from normal individuals and patients with acute and chronic myeloid leukemia or myelodysplastic syndromes. 1035 46

Changes in masticatory muscle structure and function are either developmental, as seen in anomalies of facial form, or adaptive, as seen during procedures such as orthognathic surgery and functional-appliance orthodontic therapy. Remodelling of muscle extracellular matrix is pivotal in these processes. This turnover is mediated via members of the family of enzymes known as matrix metalloproteinases (MMP) and inhibited by the tissue inhibitors of metalloproteinases (TIMP). The aim here was to investigate the in vivo pattern of expression and distribution of MMPs and TIMPs in masseter muscle of humans with both normal and abnormal facial forms. Masseter muscle biopsies were taken from 10 patients, four with long-face syndrome and six normal controls as confirmed by cephalometry. Immunohistochemical techniques were used to show the pattern and distribution of MMPs and TIMP proteins in the muscle. Zymography of tissue extracts was used to determine the presence of MMP activity. Reverse transcriptase-polymerase chain reaction (RT-PCR) was used to detect the presence of MMP and TIMP-2 mRNA. MMP-1 was expressed around the individual muscle fibres, especially in those fibre surfaces in contact with the interstices of the connective tissue and around blood vessels. MMP-9 staining was less intense and was expressed in the interstices of the connective tissue and around blood vessels. Zymography of protein extracts confirmed that MMP-9 activity was present. MMP-2 and MMP-3 were not expressed in the samples, although MMP-2 mRNA could be detected by RT-PCR and its activity could be detected by zymography. Intense TIMP-1 staining was present around each muscle fibre, in the interstices of the connective tissue and surrounding blood vessels; TIMP-2 mRNA could be detected in all samples. These staining patterns were seen in all biopsies examined and were irrespective of the facial form of the donor. These findings provide evidence that the mechanisms required for matrix remodelling are present in the human masseter muscle.
 ...
PMID:Identification of matrix metalloproteinases and their tissue inhibitors type 1 and 2 in human masseter muscle. 1077 72

We investigated the role of tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2 in the growth regulation. Primary (PM-WK and KHm-4), recurrent primary (RPM-EP and RPM-MC), lymph node metastatic (MM-AN, MM-BP and MM-RU), and a visceral metastatic (MM-LH) melanoma cell lines were used. Reverse transcriptase-coupled polymerase chain reaction and Western blotting revealed that all expressed and produced TIMP-1 and TIMP-2 except for PM-WK, which neither expressed nor produced TIMP-1. TIMP-1 and TIMP-2 secretion levels were measured by enzyme-linked immunosorbent assay in supernatants of cells. We found that the TIMP-1 production level was correlated with the cell migration rate. Moreover, TIMP-1 enhanced the cell migration of PM-WK. The growth of the primary melanoma cell lines was stimulated by TIMP-1 and inhibited by TIMP-2. In contrast, the growth of the visceral metastatic melanoma cell line was stimulated by TIMP-2.
 ...
PMID:Differential growth regulation in human melanoma cell lines by TIMP-1 and TIMP-2. 1160 52

To assess the possible involvement of vascular endothelial growth factor (VEGF) in the pathology of osteoarthritic (OA) cartilage, we examined the expression of VEGF isoforms and their receptors in the articular cartilage, and the effects of VEGF on the production of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) in OA chondrocytes. Reverse transcriptase-polymerase chain reaction analyses demonstrated that mRNAs for three VEGF isoforms (VEGF(121), VEGF(165), and VEGF(189)) are detectable in all of the OA and normal (NOR) cartilage samples. However, the mRNA expression of their receptors (VEGFR-1 = Flt-1, VEGFR-2 = KDR and neuropilin-1) was recognized only in the OA samples. The protein expression of VEGFR-1 and VEGFR-2 in OA chondrocytes was also demonstrated by immunohistochemistry of the OA cartilage tissue and cultured OA chondrocytes. In situ hybridization and immunohistochemistry indicated that VEGF is expressed in the chondrocytes in the superficial and transitional zones of OA cartilage. A linear correlation was obtained between VEGF immunoreactivity and Mankin scores in the cartilage (r = 0.906, P < 0.001). The production levels of VEGF determined by enzyme-linked immunosorbent assay were significantly 3.3-fold higher in OA than in NOR samples (P < 0.001). Among MMP-1, -2, -3, -7, -8, -9, and -13, TIMP-1 and -2 measured by their sandwich enzyme immunoassay systems, the production of MMP-1 and MMP-3 but not TIMP-1 or TIMP-2 was significantly enhanced by the treatment of cultured OA chondrocytes with VEGF (P < 0.05), whereas no such effect was obtained with cultured NOR chondrocytes. These results demonstrate that VEGF and its receptors are expressed in OA cartilage, and suggest the possibility that VEGF is implicated for the destruction of OA articular cartilage through the increased production of MMPs.
 ...
PMID:Vascular endothelial growth factor isoforms and their receptors are expressed in human osteoarthritic cartilage. 1250

In contrast to adult cutaneous wounds, early fetal wounds heal scarlessly. Fetal rat skin transitions from scarless repair to healing, with scar formation between days 16.5 (E16) and 18.5 (E18) of gestation. Term gestation is 21.5 days. The composition of the extracellular matrix in fetal skin and wounds differs from that of the adult. Matrix metalloproteinases (MMPs) and their tissue-derived inhibitors (TIMPs) determine the architecture of the extracellular matrix. The authors hypothesized that differential expression of MMPs and TIMPs occurs during the ontogenetic transition to scar-forming repair in fetal skin and wounds. Full-thickness, excisional wounds (2 mm) were created on the dorsum of E16 (n = 42 fetuses) and E19 fetal rats (n = 42 fetuses). Wounds were harvested at 24, 48, and 72 hours. Nonwounded skin from littermates was also harvested as controls. Six E16 and E19 wounds were fixed 72 hours after injury, stained with hematoxylin and eosin, and examined by light microscopy. RNA was isolated from the remaining wounds and skin, and a reduced-cycle, primer-specific, reverse-transcriptase polymerase chain reaction was performed to semiquantitatively determine relative gene expression of MMP-1, MMP-2, MMP-7, MMP-9, and MMP-14 and of TIMP-1, TIMP-2, and TIMP-3. Significance was determined by unpaired two-tailed t test (p < 0.05) and analysis of variance. In both E16 and E19 wounds, reepithelialization was complete by 72 hours. E16 wounds healed scarlessly, whereas E19 wounds healed with scar. During late gestation, skin expression of MMP-1 and MMP-14 (membrane type-1 MMP) doubled, whereas MMP-2 expression increased nearly 50-fold. Levels of MMP-7 and MMP-9 were unchanged in developing skin. As for the TIMPs, skin expression of TIMP-2 increased more than four-fold, whereas TIMP-1 and TIMP-3 expression was unchanged. In both scarless and scarring wounds, up-regulation of MMP-1 and MMP-9 occurred. However, the maximal increase in MMP-1 and MMP-9 expression occurred much more rapidly and was much greater in the scarless E16 wounds (28-fold versus 23-fold for MMP-1 and 18-fold versus nine-fold for MMP-9). Unchanged in scarless wounds, MMP-2 levels decreased more than three-fold in scarring wounds. MMP-14 (membrane type-1 MMP) expression increased three-fold in scarless wounds but was unchanged in scarring wounds. In contrast, TIMP-1 and TIMP-3 expression in E19 scarring wounds increased six-fold and four-fold, respectively. MMP-7 and TIMP-2 expression did not change in response to injury. E16 scarless wounds have greater MMP relative to TIMP expression than E19 scarring wounds. This favors extracellular matrix turnover, facilitates migration of fetal cells, and promotes scarless repair.
 ...
PMID:Scarless fetal wounds are associated with an increased matrix metalloproteinase-to-tissue-derived inhibitor of metalloproteinase ratio. 1279 70

Tumor embolism occurs in 30 to 50% of all cases of cardiac myxoma, but the causes are still uncertain. Matrix metalloproteinases (MMPs) are proteolytic enzymes that degrade the extracellular matrix (ECM) and play a crucial role in plaque instability and aortic aneurysm development, in addition to cancer and heart failure. To determine whether MMP activity contributes to tumor embolism, we examined 27 left atrium-sided myxomas, 10 of which showed clinical signs of peripheral embolism. Immunohistochemistry (in all cases) and Western blotting, and in situ and in-gel zymography (in four embolic and six nonembolic consecutive tumors) demonstrated higher expression and activity of MT1-MMP, pro-MMP-2, and pro-MMP-9 in embolic myxomas, whereas pro-MMP-1, MMP-3, and TIMP-1 levels were similar to those of nonembolic tumors. Reverse transcriptase-polymerase chain reaction demonstrated that increased MMP activity was due, at least in part, to increased transcription and that TIMP-2 transcripts increased in embolic myxomas. In vitro, embolic tumor cells retained higher MT1-MMP and pro-MMP-2 levels in basal conditions and after stimulation with interleukin-1beta and interleukin-6. Increased MMP synthesis and release correlated with enhanced ECM degradation products containing glycosaminoglycan chains in embolic myxoma tissue. Our results strongly suggest that MMP overexpression may contribute to an excessive degradation of tumor ECM and increase the risk of embolism in cardiac myxomas.
 ...
PMID:Increased expression and activity of matrix metalloproteinases characterize embolic cardiac myxomas. 1592 Jan 47

Matrix metalloproteinases (MMPs) and the tissue inhibitors of MMPs (TIMPs) have been suggested to play a role in dental pulp destruction. This study examined the effects of interleukin (IL)-1 alpha on pulp fibroblasts. The ability of these cells to degrade collagen was determined with or without IL-1 alpha utilizing a cell-mediated collagen degradation assay. Reverse transcriptase-polymerase chain reaction was utilized to examine the mRNA expression of multiple MMPs and TIMPs with and without IL-1 alpha, while Western blot analyses and zymography were utilized to examine their protein expression. The collagen degradation mediated by these cells was stimulated by IL-1 alpha and inhibited by MMP inhibitors. IL-1 alpha increased the mRNA expression of MMP-1 and MMP-3, as well as induced MMP-7. Western blot analyses confirmed these results. IL-1 alpha increased the secreted protein level of TIMP-1, while only slightly affected the level of TIMP-2. These results suggest that IL-1 alpha can induce pulp destruction by differentially regulating MMPs and TIMPs.
 ...
PMID:Interleukin-1 alpha alters the expression of matrix metalloproteinases and collagen degradation by pulp fibroblasts. 1650 Feb 23

Dental pulp destruction is believed to be regulated, in part, by the matrix metalloproteinases (MMPs) and tissue inhibitors of MMPs (TIMPs). Cytokines are believed to be important in the pathogenesis of pulpitis. This study examined the effects that TNF-alpha, IL-1beta, IL-6, and TGF-beta1 have on the collagen degradation mediated by pulp fibroblasts utilizing a cell-mediated collagen degradation assay. Reverse transcriptase-polymerase chain reaction, Western blot analyses, and zymography were utilized to examine multiple MMPs and TIMPs. The collagen degradation mediated by these cells was stimulated by these cytokines. TNF-alpha, IL-1beta, and IL-6 increased the mRNA and/or protein expression of MMP-1, MMP-2, and MMP-3. TGF-beta1 decreased MMP-1 mRNA expression, while only slightly affecting the MMP-2 and MMP-3 mRNA and/or protein. These cytokines did not affect the expression of TIMP-1 or TIMP-2. These results suggest that these cytokines affect pulp destruction, in part, by differentially regulating the MMPs and TIMPs.
 ...
PMID:The effects of tumor necrosis factor-alpha, interleukin-1beta, interleukin-6, and transforming growth factor-beta1 on pulp fibroblast mediated collagen degradation. 1693 28