Tissue inhibitor of metalloproteinases (TIMP-1) stimulates the secretion of collagenase from human skin fibroblasts

Effect of orthodontic forces on levels of enzymes in gingival crevicular fluid (GCF): A systematic review

Objective:

Orthodontic force application releases multiple enzymes in gingival crevicular fluid (GCF) for activation, resorption, reversal, deposition of osseous elements and extracellular matrix degradation. The current systematic review critically evaluated all existing evidence on enzymes in orthodontic tooth movement.

Methods:

Literature was searched with predetermined search strategy on electronic databases (PubMed, Scopus, Embase), along with hand search.

Results:

Initial search identified 652 studies, shortlisted to 52 studies based on PRISMA. Quality assessment further led to final inclusion of 48 studies (13 moderately and 35 highly sensitive studies). Primary outcomes are significant upregulation in GCF levels of enzymes-aspartate aminotransferase (AST), alkaline phosphatase (ALP), matrix metalloproteinases (MMPs), lactate dehydrogenase (LDH), β-glucuronidase (βG), tartrate resistant acid phosphatase (TRAP), acid phosphatase (ACP) and down regulation in cathepsin B (Cb). Site specificity is shown by ALP, TRAP, AST, LDH, MMP9 with levels at compression site increasing earlier and in higher quantities compared with tension site. ALP levels are higher at tension site only in retention. A positive correlation of LDH, ALP and AST is also observed with increasing orthodontic force magnitude.

Conclusions:

A strong evidence of variation in enzymes (ALP, AST, ACP TRAP, LDH, MMPs, Cb) in GCF is found in association with different magnitude, stages and sites of orthodontic force application.

Imbalances between matrix metalloproteinases (MMPs) and tissue inhibitor of metalloproteinases (TIMPs) in maternal serum during preterm labor

BACKGROUND

Matrix metalloproteinases (MMPs) are involved in remodeling of the extracellular matrix (ECM) during pregnancy and parturition. Aberrant ECM degradation by MMPs or an imbalance between MMPs and their tissue inhibitors (TIMPs) have been implicated in the pathogenesis of preterm labor, however few studies have investigated MMPs or TIMPs in maternal serum. Therefore, the purpose of this study was to determine serum concentrations of MMP-3, MMP-9 and all four TIMPs as well as MMP:TIMP ratios during term and preterm labor.

METHODS

A case control study with 166 singleton pregnancies, divided into four groups: (1) women with preterm birth, delivering before 34 weeks (PTB); (2) gestational age (GA) matched controls, not in preterm labor; (3) women at term in labor and (4) at term not in labor. MMP and TIMP concentrations were measured using Luminex technology.

RESULTS

MMP-9 and TIMP-4 concentrations were higher in women with PTB vs. GA matched controls (resp. p = 0.01 and p<0.001). An increase in MMP-9:TIMP-1 and MMP-9:TIMP-2 ratio was observed in women with PTB compared to GA matched controls (resp. p = 0.02 and p<0.001) as well as compared to women at term in labor (resp. p = 0.006 and p<0.001). Multiple regression results with groups recoded as three key covariates showed significantly higher MMP-9 concentrations, higher MMP-9:TIMP-1 and MMP-9:TIMP-2 ratios and lower TIMP-1 and -2 concentrations for preterm labor. Significantly higher MMP-9 and TIMP-4 concentrations and MMP-9:TIMP-2 ratios were observed for labor.

CONCLUSIONS

Serum MMP-9:TIMP-1 and MMP-9:TIMP-2 balances are tilting in favor of gelatinolysis during preterm labor. TIMP-1 and -2 concentrations were lower in preterm gestation, irrespective of labor, while TIMP-4 concentrations were raised in labor. These observations suggest that aberrant serum expression of MMP:TIMP ratios and TIMPs reflect pregnancy and labor status, providing a far less invasive method to determine enzymes essential in ECM remodeling during pregnancy and parturition.

Histological, hormonal and biomolecular analysis of the pathogenesis of ovine Prolapsus vaginae ante partum

The objectives of the present study were to evaluate the hormonal profiles, histology of the vagina and biomolecular analysis of connective tissue of ewes with and without vaginal prolapse. Blood samples from the jugular vein and biopsies of the vaginal tissue were taken from five late term pregnant, unaffected animals, four sheep during parturition and six ewes suffering from vaginal prolapse ante partum. The blood samples were submitted for determining the concentration of the steroid hormones progesterone by automatic luminescence immunoassay and estradiol-17β by the sequence test. Investigations in the mRNA-expression including the estimation of the transcript levels of the α(2)-chain of collagen I, the collagenolytic metalloproteinase 1 (MMP 1), the tissue inhibitor of MMP 1 (TIMP 1) and the estrogen receptor α were carried out by using semiquantitative reverse transcription-PCR. Additionally, the histology of the vaginal wall of ewes with and without vaginal prolapse and animals intra partum was assessed. Because of a right-skewed distribution, data were logarithmised and described using the geometric mean (xg) and the dispersion factor (DF). The average progesterone concentration of affected ewes (xg = 19.35 ng/ml, DF 1.33) was above those of control animals ante (xg = 10.44 ng/ml, DF 1.58) and intra partum (xg = 9.24 ng/ml, DF 1.92). Compared to the pregnant control group (xg = 20.13 pg/ml, DF 1.49) the plasma levels of 17β-estradiol in animals suffering from ante partum vaginal prolapse (xg = 27.81 pg/ml, DF 1.56) appeared to be slightly increased, but the difference was without statistical significance. The analysis of mRNA expression revealed a difference in the ante partum collagen metabolism in affected sheep. In prolapsed tissue the α2-chain of collagen I showed a decreased expression level in relation to the control animals in late-term pregnancy (P < 0.01). The average mRNA synthesis of MMP 1 or TIMP 1 in affected ewes was higher or lower, respectively, than the synthesis in healthy, late-term pregnant sheep. Significant differences were not observed. The production of transcripts of the estrogen receptor α was significantly decreased within the group of affected sheep compared to the unaffected pregnant ewes. Histological assessment showed that oedema was only detected in the subepithelial zone of the vaginal wall of intra partum sheep. There was no evidence for an inflammation of the prolapsed vaginal tissue since infiltration of leucocytes was present in all samples equally. The thickest vaginal epithelium due to hyperplasia of the epithelial cells was observed in sheep suffering from ante partum vaginal prolapse (xg = 83.95 μm, DF 1.21). This difference was statistically significant between the ante (xg = 31.12 μm, DF 1.22) and intra partum groups (xg = 33.27 μm, DF 1.24). Peripheral concentrations of progesterone and estradiol-17β seem to have no influence on the occurrence of vaginal prolapse in ewes. Regarding histology of the vaginal wall in combination with the expression of local estrogen receptors, it was determined that there is neither a pronounced oedema nor an overexpression of the estrogen receptor α in affected animals, which means that no local estrogenic effect provokes the prolapse of vaginal tissue. The biomolecular analysis led to the new result, that ewes suffering from vaginal prolapse show alterations in the antepartal metabolism of vaginal connective tissue.

Matrix metalloproteinases and tissue inhibitors of metalloproteinases in gingival crevicular fluid during orthodontic tooth movement

Orthodontic tooth movement requires extensive re-modelling of the periodontium. Matrix metalloproteinases (MMPs) degrade the extracellular matrix during re-modelling, while their activity is regulated by the tissue inhibitors of metalloproteinases (TIMPs). The aim of this study was to investigate differences in MMP and TIMP levels in the gingival crevicular fluid (GCF) at the resorption and apposition sides of orthodontically moved teeth, and to compare these with control teeth. GCF samples were collected from eight orthodontic patients wearing fixed appliances with superelastic nickel-titanium coil springs. The samples were analysed by gelatin zymography, which allows detection of both active and latent MMPs, and reverse zymography for analysis of TIMPs. Western blotting was performed to confirm the identity of MMPs. The data were analysed using either the one-way analysis of variance or the Kruskal-Wallis test. In general, higher levels of MMPs and TIMPs were found at both the resorption and apposition sides compared with the control teeth. Remarkably, partially active MMP-1 was found in GCF from both the resorption and the apposition side but was barely present at the control teeth. TIMP-1 was strongly increased at the apposition side. Gelatinases were mainly present at the resorption side, while gelatinolytic fragments were exclusively detected at the apposition side. MMP-9, which is known to be involved in bone degradation, and a 48 kDa gelatinase were increased at the resorption side. The small increase in TIMP-1 at the resorption side might stimulate bone resorption, whereas the large increase at the apposition side reduces bone resorption. The analysis of MMPs and TIMPs may contribute to the improvement of orthodontic treatment regimens.

Spiral ligament fibrocytes release chemokines in response to otitis media pathogens

CONCLUSION

Spiral ligament fibrocytes (SLFs) may be involved in the innate immune response of the inner ear by producing chemoattractants for recruiting inflammatory cells such as neutrophils and monocytes.

OBJECTIVE

The purpose of this study was to investigate the cellular responses of SLFs when challenged by inflammatory stimuli such as components of otitis media pathogens or proinflammatory cytokines.

MATERIALS AND METHODS

To detect released inflammatory cytokines and chemokines, cells were treated for 48 h with whole lysates of nontypable Haemophilus influenzae (NTHi), Streptococcus pneumoniae, or with interleukin 1 alpha (IL-1alpha). The culture medium was then collected and applied to protein arrays. To compare mRNA levels of chemokines, total RNA was extracted after 3 h of treatment with the above agents, and quantitative real-time PCR was performed.

RESULTS

Protein array analysis showed that in response to NTHi or S. pneumoniae, rat SLFs released monocyte chemotactic protein 1, macrophage inflammatory protein 3 alpha, TNF-alpha, and cytokine-induced neutrophil chemoattractant 2 and 3. Treatment with IL-1alpha, on the other hand, resulted in release of MCP-1 but not the other molecules. Tissue inhibitor of metalloproteinase 1 and vascular endothelial growth factor were released regardless of the inflammatory stimulus used.

Tissue inhibitor of metalloproteinase-1 deficiency amplifies acute lung injury in bleomycin-exposed mice

Bleomycin-induced lung injury triggers a profound and durable increase in tissue inhibitor of metalloproteinase (TIMP)-1 expression, suggesting a potential role for this antiproteinase in the regulation of lung inflammation and fibrosis. TIMP-1 protein induction is spatially restricted to areas of lung injury as determined by immunohistochemistry. Using TIMP-1 null mutation mice, we demonstrate that TIMP-1 deficiency amplifies acute lung injury as determined by exaggerated pulmonary neutrophilia, hemorrhage, and vascular permeability compared with wild-type littermates after bleomycin exposure. The augmented pulmonary neutrophilia observed in TIMP-1-deficient animals was not found in similarly treated TIMP-2-deficient mice. Using TIMP-1 bone marrow (BM) chimeric mice, we observed that the TIMP-1-deficient phenotype was abolished in wild-type recipients of TIMP-1-deficient BM but not in TIMP-1-deficient recipients of wild-type BM. Acute lung injury in TIMP-1-deficient mice was accompanied by exaggerated gelatinase-B activity in the alveolar compartment. TIMP-1 deficiency did not alter neutrophil chemotactic factor accumulation in the injured lung nor neutrophil migration in response to chemotactic stimuli in vivo or in vitro. Moreover, TIMP-1 deficiency did not modify collagen accumulation after bleomycin injury. Our results provide direct evidence that TIMP-1 contributes significantly to the regulation of acute lung injury, functioning to limit inflammation and lung permeability.

Down-regulation of tissue inhibitor of matrix metalloprotease-1 (TIMP-1) in aged human skin contributes to matrix degradation and impaired cell growth and survival

Up regulation of matrix metalloproteinases (MMPs), particularly collagenase-1 (MMP-1), stromelysin-1 (MMP-3) and gelatinase A (MMP-2) is responsible for the lysis of dermal collagen and elastin fibers during chronological skin aging. Tissue inhibitor of metalloproteinase-1 (TIMP-1) is one representative of the natural MMP inhibitor family, encompassing four members. Its expression is decreased with fibroblast senescence, both ex vivo and in vivo, thus contributing to increased catabolic activity within dermis. TIMP-1 displays multiple biological functions. It inhibits most MMPs, except membrane-type MMP subfamily, with Ki in the subnanomolar range, but also interacts with the hemopexin-like (PEX) domain of pro MMP-9. Besides, it exhibits keratinocyte and fibroblast growth factor-like activity and has been described as a cell survival factor.

Low molecular weight inhibitors of matrix metalloproteinases can enhance the expression of matrix metalloproteinase-2 (gelatinase A) without inhibiting its activation

BACKGROUND

In the current study, the authors investigated the effects of synthetic low molecular weight inhibitors of matrix metalloproteinases (MMPs) on the expression and activation of MMP-2 in a three-dimensional tissue system.

METHODS

Rabbit periosteal explants were cultured with or without various concentrations of the MMP inhibitors CT1166, CT1399, or CT1746, and conditioned media and tissue extracts were analyzed for the expression and activity of MMP-2.

RESULTS

The data showed that blocking the activity of all MMPs with relatively high inhibitor concentrations completely prevented the conversion of pro-MMP-2 into its active form and that the level of protein was decreased. Selective inhibition of the activity of gelatinases (MMP-2 and MMP-9) by using low inhibitor concentrations, however, induced a higher level of active MMP-2 and increased its expression significantly.

CONCLUSIONS

The current observations indicate that selective inhibitors of MMPs affect the expression and activity of MMP-2, thus providing clues regarding the differing effects such inhibitors appear to have when applied in vivo.

MMPs and TIMP-1 are differentially expressed between acute murine excisional and laser wounds

BACKGROUND AND OBJECTIVES

Matrix metalloproteinases (MMPs) and their physiological inhibitors, the tissue inhibitors of metalloproteinases (TIMPs) play significant roles in wound repair. The aim of this study was to determine whether MMP and TIMP-1 mRNA is differentially expressed between laser-created and excisional skin wounds.

STUDY DESIGN/MATERIALS AND METHODS

Full-thickness wounds were created on the dorsal surface of Balb/c mice by either excision of the skin or with a CO2 laser. Animals were sacrificed at days 1, 3, 5, 7, 10, and 13, and their wounds processed for RNA isolation or histology and immunohistochemistry.

RESULTS

Northern hybridization for MMP-3, -10, -13, and TIMP-1 mRNA demonstrated higher expression on days 1, 3, and 5 in the laser wounds as compared to the excisional wounds. Histological evaluation revealed a two day delay in the resurfacing of laser wounds as compared to excisional wounds. Immunohistochemistry of Day 5 and 7 excisional and laser wounds showed MMP-3 within the epidermal compartment and the neo-dermis. No remarkable differences were noted in the spatial distribution patterns of MMP-3 between wound types.

CONCLUSIONS

Our findings demonstrate that MMPs and TIMP-1 mRNA expression is higher on days 1-5 post injury in full thickness laser-created wounds than in comparable same day excisional wounds.

Disruption of the tissue inhibitor of metalloproteinase-1 gene in reproductive-age female mice is associated with estrous cycle stage-specific increases in stromelysin messenger RNA expression and activity

Tissue inhibitors of metalloproteinases (TIMPs) are expressed in the uteri of virtually all species, yet the precise role of these factors in uterine physiology is uncertain. It has been previously demonstrated that disruption of the TIMP-1 gene product in vivo results in altered reproductive cycles and an aberrant uterine phenotype. Because this phenotype may be due to an elevation in uterine matrix metalloproteinase (MMP) activity, the purpose of the following experiments was to identify which uterine MMPs may have their expression altered in response to disruption of the TIMP-1 gene. Mature female TIMP-1 wild-type and null mice were killed during each stage of the estrous cycle, and uterine MMP activity and transcript expression were assessed. Disruption of the TIMP-1 gene product was associated with an increase in total uterine protease activity. Gel zymography further revealed that uterine stromelysin (stromelysin-1, -2, and -3) activity was significantly increased in the TIMP-1 null mice, whereas Northern blot analysis indicated that an up-regulation of stromelysin-1 and -3 mRNA expression may contribute to this increase in activity. It is concluded from this study that TIMP-1 plays a pivotal role in regulating uterine stromelysins both at the level of protease activity and the level of transcript expression.

Impaired migration, integrin function, and actin cytoskeletal organization in dermal fibroblasts from a subset of aged human donors

Deficits in the motility of fibroblasts contribute to age-related impairment of wound healing. We analyzed 'young' fibroblasts from four healthy donors 22-30 years old and 'aged' fibroblasts from six healthy donors 81-92 years old for migratory ability on type I collagen, secretion of matrix metalloproteases (MMPs), attachment to matrices and, expression and function of integrin alpha2beta1. Cells from each donor were analyzed separately in each experiment. Whereas migration of young fibroblasts was uniformly robust, three aged lines migrated well and three migrated poorly. Synthesis of MMP1 and TIMP1, but not MMP2 or MMP9, was increased in the aged fibroblasts relative to the young fibroblast lines irrespective of their motility. All lines of young and aged fibroblasts attached to plastic or collagen with similar efficiency. Although young and aged fibroblasts expressed comparable levels of the alpha2 integrin; the lines of aged fibroblasts that were poor migrators exhibited a significant reduction in alpha2beta1 function relative to fibroblasts with normal migratory capacities. Moreover, the lines of aged fibroblasts that exhibited poor migration demonstrated a disordered actin cytoskeleton and a reduced ability to contract collagen gels. In conclusion, aged fibroblasts, unlike young fibroblasts, displayed variable migratory capacities. Deficient migration by specific lines of aged fibroblasts was not related to the capacity to attach, express alpha2 integrin, or secrete MMPs and TIMP1, but was characterized by disorganized cytoskeletal actin and reduced alpha2beta1 function.

Selective induction of tissue inhibitor of metalloproteinase-1 in bleomycin-induced pulmonary fibrosis

Tissue inhibitors of metalloproteinases (TIMPs) are multifunctional proteins that have the capacity to modify cellular activities and to modulate matrix turnover. We demonstrate that TIMP-1 messenger RNA (mRNA) and protein expression are selectively and markedly increased in a murine model of bleomycin-induced pulmonary fibrosis. Northern analysis showed that lung steady-state TIMP-1 mRNA levels increased 14-fold after bleomycin administration compared with control mice. Expression of the genes for TIMP-2, TIMP-3, and interstitial collagenase (matrix metalloproteinase-13) was unaltered in the injured lung. In situ hybridization demonstrated that TIMP-1 gene induction was spatially restricted to areas of lung injury. Metalloproteinase inhibitory activity of relative molecular mass of ~ 21 to 28 kD, corresponding to the molecular weights for TIMP-1 and TIMP-2, was identified in lung extracts of bleomycin-injured mice by reverse zymography. Western analysis demonstrated that TIMP-1 protein levels in bronchoalveolar lavage fluid (BALF) of bleomycin-treated mice increased 220- and 151-fold at Days 4 and 28, respectively, compared with control mice. TIMP-2 immunoreactive protein in the BALF increased 20- and 103-fold relative to controls at Days 4 and 28, respectively. These results demonstrate that TIMP-1 gene expression is selectively increased, and that the expression of TIMP-1 and TIMP-2 is differentially regulated in bleomycin-induced pulmonary fibrosis. The profound and durable increase in TIMP-1 and TIMP-2 proteins suggests an important regulatory role for these antiproteases in the inflammatory and fibrotic responses to bleomycin-induced lung injury.

Paradoxical effects of tissue inhibitor of metalloproteinases 1 gene transfer in collagen-induced arthritis

OBJECTIVE

The imbalance between matrix metalloproteinases (MMPs) 1, 3, and 9 and their specific inhibitor, tissue inhibitor of metalloproteinases 1 (TIMP-1), is a critical step in cartilage injury and angiogenesis in arthritis. To explore the therapeutic potential of TIMP-1 gene transfer in erosive arthritis, the effects of an adenoviral vector (Ad-TIMP-1) were assessed in DBA/1 mice with collagen-induced arthritis (CIA).

METHODS

DBA/1 mice with CIA received an intravenous injection of replication-deficient adenovirus containing the human TIMP-1 gene or a control LacZ gene on day 28 postimmunization. The efficiency of gene transfer was determined by serum TIMP-1 detection, measurements of paw swelling, as well as radiologic and histologic examination of the paws.

RESULTS

A single administration of Ad-TIMP-1 resulted in detectable serum levels of the exogenous protein for at least 13 days. The incidence and onset of arthritis were not statistically modified after human TIMP-1 gene transfer in DBA/1 mice compared with control mice. However, the severity of inflammation was statistically significantly increased in Ad-TIMP-1-treated mice and a similar trend was observed in the histologic and radiologic scores. With regard to the mechanisms of the worsened effect in the Ad-TIMP-1-treated mice, we observed 1) higher serum levels of anti-type II collagen IgG2a, 2) a significant increase in endogenous soluble tumor necrosis factor receptor I (TNFRI) in sera, and 3) increased labeling of mouse tumor necrosis factor alpha and TNFRI within arthritic joints.

CONCLUSION

These findings show that overexpression of TIMP-1 does not prevent osteochondral injury in a mouse model of arthritis. Since MMPs have overlapping properties in terms of their roles in extracellular matrix degradation, angiogenesis, and shedding of cell surface adhesion molecules, cytokines, and cytokine receptors, the paradoxical results obtained suggest that TIMP-1 is probably not the main inhibitor to target.

Tissue factor pathway inhibitor-2 is a novel inhibitor of matrix metalloproteinases with implications for atherosclerosis

Degradation of ECM, particularly interstitial collagen, promotes plaque instability, rendering atheroma prone to rupture. Previous studies implicated matrix metalloproteinases (MMPs) in these processes, suggesting that dysregulated MMP activity, probably due to imbalance with endogenous inhibitors, promotes complications of atherosclerosis. We report here that the serine proteinase inhibitor tissue factor pathway inhibitor-2 (TFPI-2) can function as an MMP inhibitor. TFPI-2 diminished the ability of the interstitial collagenases MMP-1 and MMP-13 to degrade triple-helical collagen, the primary load-bearing molecule of the ECM within human atheroma. In addition, TFPI-2 also reduced the activity of the gelatinases MMP-2 and MMP-9. In contrast to the "classical" tissue inhibitors of MMPs (TIMPs), TFPI-2 expression in situ correlated inversely with MMP levels in human atheroma. TFPI-2 colocalized primarily with smooth muscle cells in the normal media as well as the plaque's fibrous cap. Conversely, the macrophage-enriched shoulder region, the prototypical site of matrix degradation and plaque rupture, stained only weakly for TFPI-2 but intensely for gelatinases and interstitial collagenases. Evidently, human mononuclear phagocytes, an abundant source of MMPs within human atheroma, lost their ability to express this inhibitor during differentiation in vitro. These findings establish a new, anti-inflammatory function of TFPI-2 of potential pathophysiological significance for human diseases, including atherosclerosis.

The role of oncostatin M in animal and human connective tissue collagen turnover and its localization within the rheumatoid joint

OBJECTIVE

To study the interaction of interleukin-1alpha (IL-1alpha) and oncostatin M (OSM) in promoting cartilage collagen destruction.

METHODS

Bovine, porcine, and human cartilage and human chondrocytes were studied in culture. The levels of collagenase (matrix metalloproteinase 1 [MMP-1]) and tissue inhibitor of metalloproteinases 1 (TIMP-1) were measured by bioassay and enzyme-linked immunosorbent assay (ELISA). The levels of OSM in rheumatoid synovial fluid were measured by ELISA.

RESULTS

When combined with OSM, IL-1alpha, IL-1beta, and tumor necrosis factor alpha released proteoglycan and collagen from cartilage. OSM was the only member of the IL-6 family to have this effect. Human tendon also responded to IL-1alpha and OSM. OSM increased the production of MMP-1 and TIMP-1 but when combined with IL-1alpha, synergistically promoted MMP-1 production in human chondrocytes and synovial fibroblasts. High levels of OSM were found in human rheumatoid synovial fluids, and confocal microscopy showed that OSM was produced by macrophages in rheumatoid synovial tissue.

CONCLUSION

These results highlight an important new mechanism by which there is irreversible loss of collagen from cartilage.

Human ageing impairs injury-induced in vivo expression of tissue inhibitor of matrix metalloproteinases (TIMP)-1 and -2 proteins and mRNA

Proteolysis is an essential component of wound healing but, if uncontrolled, it may lead to degradation of the neo-matrix and a delay in wound repair. Despite numerous reports of impaired wound healing associated with increasing age, the control of proteolysis is completely unknown. Tissue inhibitor of matrix metalloproteinases (TIMP)-1 and -2 inhibit the activity of matrix metalloproteinases and the pattern of regulation of these molecules determines in part the spatial and temporal regulation of proteolytic activity. This study reports on TIMP-1 and -2 protein localization using immunocytochemistry in healing wounds of healthy subjects of different ages from day 1 to 6 months post-wounding, and has quantified the mRNA levels for both inhibitors using reverse transcriptase-polymerase chain reaction (RT-PCR). TIMP-1 and TIMP-2 proteins are up-regulated from 24 h post-wounding, with a decrease in staining intensity by day 7 for TIMP-2 and by day 14 for TIMP-1. Steady-state mRNA levels for both TIMPs were significantly greater in normal young skin than in aged skin. In the young, there was a significant increase in mRNA expression for TIMP-1 and -2 by day 3 post-wounding, which decreased by day 14 and had returned to basal levels at day 21. In the wounds of the aged subjects, basal levels were observed for TIMP-1 and -2 at all time-points. These results suggest that intrinsic cutaneous ageing is associated with reduced levels of TIMP mRNA both in normal skin and during acute wound repair. These levels may be instrumental in dermal tissue breakdown in normal skin, retarded wound healing, and the predisposition of the elderly to chronic wound healing states.

Transcriptional activity of the human tissue inhibitor of metalloproteinases 1 (TIMP-1) gene in fibroblasts involves elements in the promoter, exon 1 and intron 1

The active forms of all of the matrix metalloproteinases (MMPs) are inhibited by a family of specific inhibitors, the tissue inhibitors of metalloproteinases (TIMPs). Inhibition represents a major level of control of MMP activity. A detailed knowledge of the mechanisms controlling TIMP gene expression is therefore important. We have isolated a genomic clone of the human TIMP-1 gene. A 3 kbp XbaI fragment has been sequenced; this fragment contains 1718 bp 5' flanking sequences, exon 1, a 929 bp intron 1 and part of exon 2. Computer analysis reveals 10 consensus sequences for Sp1, six for activating protein 1 (AP-1), six for polyoma enhancer A3 (PEA3), 12 for AP-2 and five CCAAT boxes. The region hybridizing with a murine TIMP-1 promoter fragment has been subcloned and analysed further. RNase protection identifies six transcription start points, making exon 1 up to 48 bp in length. Transient transfection of promoter-chloramphenicol O-acetyltransferase reporter constructs into primary human connective tissue fibroblasts shows that a 904 bp fragment that hybridizes to a murine TIMP-1 promoter fragment contains a functional promoter. Constructs of -738/+95 to -194/+21 are inducible with serum or phorbol ester to a similar extent to the endogenous TIMP-1 gene. These results and further mapping with 5' deletion mutants from the -738/+95 region have demonstrated that an AP-1 site at -92/-86 is essential for basal expression of the gene. Point mutations within this region have further confirmed the role of this site, along with a more minor role for a neighbouring PEA3 site, in basal expression. Deletions from the 3' end also implicate a region across the exon 1/intron 1 boundary and especially +21 to +58 in basal expression. The +21/+58 region contains a putative binding site for the transcription factor leader-binding protein 1 (LBP-1). Gel-shift analysis shows that protein binds specifically to this region, but competition studies suggest that it is unlikely to be LBP-1.

TIMP-3 mRNA expression is regionally increased in moderately and poorly differentiated colorectal adenocarcinoma

In this study, we report on the distribution of tissue inhibitor of matrix metalloproteinase-3 (TIMP-3) mRNA expression in human normal colorectal mucosa, adenomas and adenocarcinomas. Northern blot analysis showed five TIMP-3 mRNA transcripts to be present in normal mucosal epithelium and in moderately and poorly differentiated carcinoma. Adenomas and well-differentiated carcinomas were not examined in this part of the investigation. In situ hybridization studies showed no detectable TIMP-3 mRNA in normal and adenomatous tissue. In contrast, TIMP-3 mRNA is localized to stromal fibroblast-like cells in colorectal carcinomas, with an increased incidence in moderately and poorly differentiated groups compared with well-differentiated carcinomas. Expression in both the moderately and the poorly differentiated tumour groups was strongest at the tumour invasive edge; none of the poorly differentiated carcinomas showed mRNA expression in regions ahead of the invasive edge, compared with 3 of 12 of the moderate group. To our knowledge, this is the first detailed report on the regional localization of TIMP-3 mRNA in colorectal tumours. We suggest that the lack of TIMP-3 mRNA expression in host stromal tissues ahead of poorly differentiated carcinomas may contribute to their increased invasiveness.

Distinct pattern of matrix metalloproteinase 9 and tissue inhibitor of metalloproteinase 1 mRNA expression in human colorectal cancer and liver metastases

The matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) are perceived as essential for tumour invasion and metastasis. In the present study, we compare the topographical pattern of MMP-9 and TIMP-1 expression in colorectal cancer and liver metastasis by in situ hybridisation. TIMP-1 mRNA was detected in all 26 colorectal cancers examined, while only 18 out of 26 (69.2%) were positive for MMP-9. Both MMP-9 and TIMP-1 mRNA were observed in all ten liver metastases but were absent in three adenomas and in all normal colonic mucosa and liver. There was no association between MMP-9 or TIMP-1 mRNA expression and degree of differentiation or size of Tumours. MMP-9 and TIMP-1 mRNA were similarly observed in the peritumour stroma cells rather than in tumour cells themselves. MMP-9 mRNA positive cells were round and identified as macrophages by immunostaining with an anti-macrophage antibody (KP1), while TIMP-1, mRNA was detected in spindle-shaped stromal cells. In liver metastases, MMP-9 localised within peritumour stroma or at the interface between the tumour stroma and normal liver, whereas TIMP-1 mRNA was located throughout the malignant tumour stroma. Our data demonstrate a distinct pattern of MMP-9 and TIMP-1 mRNA expression in colorectal cancer and liver metastases suggesting distinct cellular origins as well as separate patterns of regulation.