Tissue Inhibitor Of Metalloprotease Research Articles

Matrix metalloproteases and their tissue inhibitor in cardiac transplantation☆☆☆

Multiple studies have shown that matrix metalloproteases (MMPs) are involved in the pathologic reactions occurring as a consequence of cardiac transplantation, including ischemia-reperfusion injury and allograft rejection. This study sought to determine the temporal profile of MMP serum levels following cardiac transplantation. Endomyocardial biopsies and serum samples were obtained from 66 recipients at 1, 2, 3, 4, 7, 12, 24, and 52 weeks post-transplant during the routine follow-up protocol, and MMP-1, MMP-8, MMP-9, and tissue inhibitor of metalloproteases (TIMP)-1 serum concentrations were measured by enzyme-linked immunosorbent assay (ELISA). Immunosuppression comprised cyclosporine A (CyA; n=46) or tacrolimus (TAC; n=20) with mycophenolate mofetil and steroids. Increased MMP-8, MMP-9, and TIMP-1 serum levels were observed during the first 2 weeks following transplantation compared to the later time points. MMP-1 was increased at 2 and 3 weeks post-transplant compared to all later time points. No correlation of MMP or TIMP serum concentrations with infection episodes was observed. Early increase in MMP and TIMP serum levels following cardiac transplantation indicates involvement of these molecules in the reaction of the transplant to ischemia-reperfusion or early immunologic adaptation processes of the host. Further investigation of the relationship between MMP and TIMP serum levels and clinical conditions following transplantation including allograft rejection and hemodynamic graft function is necessary.

Expression of Anaplastic Lymphoma Kinase, Tyrosine-Phosphorylated STAT3, and Associated Factors in Pediatric Anaplastic Large Cell Lymphoma

In anaplastic large cell lymphoma (ALCL), anaplastic lymphoma kinase (ALK) activates (phosphorylates) signal transducer and activator of transcription 3 (STAT3) with subsequent cytoplasmic expression, in some cases, of survivin and tissue inhibitor of metalloprotease 1 (TIMP1). These are inhibitors of apoptosis and negative prognostic factors. CD56 is also a negative prognostic marker in ALCL. We assayed 40 cases of predominantly ALK+ pediatric ALCL for pSTAT3, survivin, TIMP1, and CD56 using immunohistochemical analysis. The patients were derived from a Pediatric Oncology Group treatment protocol that showed 72% event-free survival at 4 years for ALCL. The results show that in advanced-stage pediatric ALCL, although most tumors express ALK and a majority show activated STAT3, cytoplasmic localization of survivin and TIMP1 is not frequent, nor is expression of CD56. This may help, in part, explain the relatively good prognosis of pediatric ALCL.

Proteomic Analysis of Exfoliation Deposits

To increase knowledge of the biochemical composition of lenticular exfoliation material (XFM) by using proteomic approaches. Anterior lens capsules from patients with and without exfoliation syndrome (XFS) were homogenized in formic acid and subjected to cyanogen bromide (CNBr) cleavage, and the pattern of chemically generated fragments was compared by SDS-PAGE after silver staining. Unique XFS bands not present in control cases were excised, digested with TPCK-trypsin, and the resultant peptides sequenced with quadrupole time-of-flight mass spectrometry (MS). In parallel experiments, CNBr-fragmented XFM was separately digested in solution with trypsin and elastase, and the resultant peptide mixture was analyzed by liquid chromatography coupled to tandem MS followed by identification through homology searches at nonredundant protein databases. Immunolocalization of the MS-identified components were performed in XFS versus control samples by using conventional immunohistochemical methods and light microscopy. In addition to fibrillin-1, fibronectin, vitronectin, laminin, and amyloid P-component, which are well-known extracellular matrix and basement membrane components of XFM, the proteomic approaches identified the multifunctional protein clusterin and tissue inhibitor of metalloprotease (TIMP)-3 as well as novel molecules, among them fibulin-2, desmocollin-2, the glycosaminoglycans syndecan-3, and versican, membrane metalloproteases of the ADAM family (a disintegrin and metalloprotease), and the initiation component of the classic complement activation pathway C1q. In all cases, classic immunohistochemistry confirmed their location in XFM. A novel solubilization strategy combined with sensitive proteomic analysis emphasizes the complexity of the XFS deposits and opens new avenues to study the molecular mechanisms involved in the pathogenesis and progression of XFS.

Matrix metalloprotease-9 dysregulation in lower airway secretions of cystic fibrosis patients

Matrix metalloproteases (MMPs) are proteolytic enzymes that regulate extracellular matrix turnover and aid in restoring tissue architecture following injury. There is an emerging role for extracellular matrix destruction in the pathogenesis of chronic neutrophilic lung diseases. In this study, we examined the expression and activity profiles of MMPs in lower airway secretions from cystic fibrosis (CF) patients, patients with acute respiratory failure (ARF), and normal controls. A discrete repertoire of MMP isoforms was found in the CF samples, with robust MMP-9 expression compared with normal controls and ARF. CF samples possessed increased levels of active MMP-9, as well as decreased amounts of tissue inhibitor of metalloprotease-1 (TIMP-1), a natural inhibitor of MMP-9. The CF inpatient samples demonstrated fully active MMP-9 activity compared with CF outpatients, ARF, and normal controls. CF samples also demonstrated increased human neutrophil elastase (HNE) levels compared with ARF and normal controls. To examine potential mechanisms for the protease dysregulation seen in the CF clinical samples, in vitro studies demonstrated that HNE could activate pro-MMP-9 and also degrade TIMP-1; this HNE-based activation, however, was not seen with MMP-8. A strong correlation was seen between HNE and MMP-9 activity in CF inpatient samples. Finally, the dysregulated MMP-9 activity seen in CF inpatient sputum samples could be significantly reduced by the use of MMP-9 inhibitors. Collectively, these findings further emphasize the proposed protease/antiprotease imbalance in chronic neutrophilic lung disease, providing a potential mechanism contributing to this proteolytic dysregulation.

Involvement of mast cells in the regulation of matrix metalloproteinase-9 and tissue inhibitor of metalloproteases-1 in 12- O-tetradecanoylphorbolacetate-induced inflammation in mice

In this study, we investigated the involvement of mast cells in the regulation of matrix metalloproteinase-9 (MMP-9) in 12- O-tetradecanoylphorbolacetate (TPA)-induced inflammation, using mast cell-deficient (W/W v) mice and control (+/+) mice. Topical application of TPA to the ears induced acute inflammation, accompanied by mast cell degranulation in +/+ mice, which peaked at 6–12 h. There was no significant difference in ear thickness between the groups until 12 h, but the swelling was greater in W/W v mice than +/+ mice at 24–36 h. Western blot analysis revealed that TPA-induced marked increases in levels of proMMP-9 and tissue inhibitor of metalloproteinases-1 (TIMP-1), which existed as complexes with proMMP-9. The amount of proMMP-9-TIMP-1 complex was markedly smaller in +/+ mice than W/W v mice at 6 and 24 h, but had almost returned to control levels in both groups at 48 h. The free form of proMMP-9 was also slightly less abundant in +/+ mice than W/W v mice at 6, 24, and 48 h. Gelatin zymographic analysis revealed that levels of the active species of MMP-9 (approximately 74 and 83 kD), as well as free form of proMMP-9, increased time-dependently after the application of TPA and peaked at 24 h in +/+ mice. The 74-kD band was detected only in +/+ mice at 6 h. Our results therefore suggested that during inflammation degranulation of mast cells results in a reduction of the proMMP-9-TIMP-1 complex levels, together with a fall in the amount of free proMMP-9.

Overexpression of tissue inhibitor of metalloprotease-2 promotes proliferation and infiltration of human monocytic leukemia cells

To investigate the functional role of human tissue inhibitor of metalloprotease (TIMP)-2 gene on the proliferation and infiltrating capability of human monocytic leukemic cells. Human monocytic leukemic cells of the line SHI-1 were cultured and the TIMP-2 expression on the cell membrane was detected by flow cytometry (FCM). The SHI-1 cells were transfected with human TIMP-2 gene (SHI-1/TIMP-2 cells) or blank vector (SHI-1/MSCV cells). The TIMP-2 expressed on the surface of the cell membranes of SHI-1/TIMP-2 and SHI-1/MSCV cells was detected by FCM. The SHI-1/TIMP-2 and SHI-1/MSCV cells were inoculated into the 96-well plate, 24, 48, 72, and 96 hours later MMT method and ELISA were used, and the cell growth curve was drawn to detect the proliferation ability of the cells. Matrigel was put into the upper layer of Transwell chamber. Human bone marrow matrix cells (BMMC) of leukemia patient and SHI-1/TIMP-2 cells or SHI-1/MSCV cells were put into the upper layers as experimental groups, and SHI-1/TIMP-2 cells or SHI-1/MSCV cells only, without human BMMC, were put into the upper layers as control groups. 72 hours later blood cell counting plate was used to measure the number of cells migrating through Matrigel. SHI-1/TIMP-2 cells or SHI-1/MSCV cells were injected intravenously into pre-treated BALB/c nu/nu mice. Thirty days later 8 mice from each group were killed to observe the tumorigenesis in the organs, especially the central nervous system leukemia (CNL). The survival of the other mice was observed. The expression level of TIMP-2 on the cell membrane of the SHI-1/TIMP-2 cells was 99.3% +/- 0.1%, significantly higher than that of the SHI-1/MSCV cells (85.9% +/- 2.6%, P < 0.05). The A values 24, 48, 72, and 96 hours later of the SHI-1/TIMP-2 cells were 0.34 +/- 0.05, 0.6 +/- 0.05, 0.97 +/- 0.12, and 1.28 +/- 0.06 respectively, all significantly higher than those of the SHI-1/MSCV cells (0.28 +/- 0.03, 0.36 +/- 0.03, 0.54 +/- 0.09, and 0.99 +/- 0.03 respectively, all P < 0.05). The SHI-1/TIMP-2 cells and SHI-1/MSCV cells only could not migrate through Matrigel basically. 24 - 48 hours after co-cultivation Shi-1 cells began to appear in the lower layer of Transwell chambers, 72 hours later the trans-Matrigel SHI-1/TIMP-2 cells accounted for 24.7% +/- 6.9% of the inoculated SHI-1/TIMP-2 cells, a proportion significantly higher than that in the case of the SHI-1/MSCV cells (12% +/- 1.4%, P < 0.05). 24 days after the inoculation the mean body weight of the mice inoculated with SHI-1/TIMP-2 cells was 21.5 g +/- 0.4 g, significantly higher than that of the mice inoculated with SHI-1/MSCV cells (17.4 g +/- 0.6 g, P < 0.01). The mice inoculated with SHI-1/TIMP-2 cells showed much more tumors in different organs and much more severe infiltration in the CNS in comparison with the mice inoculated with SHI-1/MSCV cells The mean survival time of the mice inoculated with the SHI-1/TIMP-2 cells was 33.7 days, significantly shorter than that of the mice inoculated with SHI-1/MSCV cells (40 days). TIMP-2 expressed on the cell membrane is critical to promote the proliferation and infiltration of SHI-1 cells.

The influence of MMP-14, TIMP-2 and MMP-2 expression on breast cancer prognosis

IntroductionMatrix metalloproteinase (MMP)-2 is very active at degrading extracellular matrix. It is under the influence of an activator, membrane type 1 MMP (MMP-14), and the tissue inhibitor of metalloproteases (TIMP)-2. We hypothesized that the individual expression of these three markers or their balance may help to predict breast cancer prognosis.MethodsMMP-2, MMP-14 and TIMP-2 expression has been evaluated by 35S mRNA in situ hybridization on paraffin material of 539 breast cancers without distant metastasis at diagnosis and with a median follow-up of 9.2 years.ResultsMMP-2 and MMP-14 mRNA was detected primarily in reactive stromal cells whereas TIMP-2 mRNA was expressed by both stromal and cancer cells. Of the three molecules, an adjusted Cox model revealed that high MMP-14 mRNA (≥ 10% cells) alone predicted a significantly shorter overall survival (p = 0.031) when adjusted for clinical factors (tumor size and number of involved lymph nodes). Prognostic significance was lost when further adjusted for Her-2/neu and urokinase-type plasminogen activator (p = 0.284). Furthermore, when all three components were analyzed together, the survival was worst for patients with high MMP-2/high MMP-14/low TIMP-2 (5 year survival = 60%) and best with low MMP-2/low MMP-14/high TIMP-2 (5 year survival = 74%), but the difference did not reach statistical significance (p = 0.3285).ConclusionOf the MMP-14/TIMP-2/MMP-2 complex, MMP-14 was the factor most significantly associated with the outcome of breast cancer and was an independent factor of poor overall survival when adjusted for clinical prognostic factors, but not for certain ancillary markers.

Differential regulation of cytokine-induced MMP-1 and MMP-13 expression by p38 kinase inhibitors in human chondrosarcoma cells: potential role of Runx2 in mediating p38 effects

To investigate mitogen activated protein (MAP) kinase pathways for their ability to differentially regulate the expression of matrix metalloprotease (MMP)-1 and -13 in human chondrosarcoma cells using pathway-selective inhibitors. Human chondrosarcoma cell lines (SW1353 and JJ012) and human articular chondrocytes (HACs) were treated with cytokines (IL-1beta and TNFalpha) and the expression of MMP-1 and -13 was analyzed. The effects of MAP kinase inhibitors on cytokine-induced expression of MMP-1 and -13 were evaluated using ELISA and Western blot analyses. The possible involvement of the Runx2 pathway in mediating p38 effects on MMP-13 expression was analyzed using promoter-reporter assays, ELISA and immunoprecipitation analyses. IL-1beta and TNFalpha strongly induced the expression of MMP-1 and -13 in SW1353 cells and HACs, whereas only TNFalpha was found to induce the expression of these two MMPs in JJ012 cells. Cytokine treatment did not result in a significant increase in the activity of MMPs because of the excess production of endogenous tissue inhibitors of metalloproteases (TIMPs). Treatment with p38 kinase inhibitors (SB203580 and SB242235) strongly inhibited cytokine-induced MMP-13 expression in a dose-dependent fashion while having a somewhat weaker inhibitory effect on MMP-1 expression. In contrast, inhibitors of extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK) pathways did not inhibit the expression of either MMP. Overexpression of Runx2 robustly stimulated the transcriptional activation of MMP-13 but had no effect on MMP-1 expression. Furthermore, IL-1beta induced the phosphorylation of Runx2, and this effect was blocked by a p38 kinase inhibitor. Our data suggest that Runx2 is likely to be a key downstream mediator of p38 effects in the differential regulation of IL-1beta induced MMP-13 expression. These studies demonstrate the differential inhibition of cytokine-induced MMP-1 and -13 expression by p38 kinase inhibitors in human chondrosarcoma cells. Our studies also suggest the involvement of Runx2, at least in part, in mediating the effects of p38 on MMP-13 expression.

Effects of norcantharidin on angiogenesis of human gallbladder carcinoma and its anti-angiogenic mechanisms

To investigate the effects of norcantharidin (NCTD) on angiogenesis of human gallbladder carcinoma and its anti-angiogenic mechanisms. Human gallbladder carcinoma cells of the line GBC-SD were cultured. BALB/c nude mice were inoculated subcutaneously with the GBC-SD cells and then randomly divided into 6 groups: NCTD group, injected intraperitoneally with 1/5 of the LD(50) of NCTD twice a week for 6 weeks; 5-fluorouracil (5-FU) group, injected intraperitoneally with 1/5 of the LD(50) of 5-FU twice a week for 6 weeks; endostatin (ES) group, intraperitoneally with ES; NCTD + 5-FU group, injected intraperitoneally with 1/5 of the LD(50) of NCTD and 1/5 of the LD(50) of 5-FU twice a week for 6 weeks; NCTD + ES group, injected intraperitoneally with 1/5 of the LD(50) of NCTD and ES twice a week for 6 weeks; and normal saline (NS) group (control group), injected with NS. The mice were killed in the 7th week. The tumors were taken out to measure their volumes and undergo microscopy. SABC method of immunohistochemistry was used to measure the microvessel density (MVD) and the protein expression of the angiogenesis-related factors: proliferating cell nuclear antigen (PCNA), vascular endothelial growth factor (VEGF), angiopoietin (Ang)-2, thrombospondin (TSP), and tissue inhibitor of metalloprotease (TIMP)(2). Suspension of single tumor cell was prepared to examine the cell apoptosis by flow cytometry. RT-PCR was used to examine the mRNA expression of PCNA, VEGF, Ang-2, TSP, and TIMP2. (1) The MVD of the NCTD group was 4.12 +/- 1.4, significantly lower than those of the 5-FU group (15.8 +/- 5.9) and control group (17.6 +/- 3.2) (both P < 0.01), but not significantly different from those of the NCTD + 5-FU group (3.8 +/- 1.7), ES group (4.5 +/- 2.1), and NCTD + ES group (2.9 +/- 1.5) (all P > 0.05). The mice treated with NCTD showed significantly smaller tumor volume, lower PCNA protein expression, higher apoptotic rate, and higher PCNA/apoptosis ratio (P < 0.05 or P < 0.01), and significant correlation between MVD and tumor volume and between MVD and PCNA/apoptosis ratio (both P < 0.05). (2) The protein expression of VEGF and of Ang-2 of the NCTD group were both significantly lower than those of the control and 5-FU groups (all P < 0.01), however, not significantly different from those of the ES, NCTD + 5-FU, and NCTD + ES groups; and the protein expression of TSP and of TIMP2 of the NCTD group were both significantly higher than those of the control and 5-FU groups (all P < 0.01), however, not significantly different from those of the ES, NCTD + 5-FU, and NCTD + ES groups. MVD was positively correlated with VEGF and Ang-2 expression and negatively correlated with the expression of TSP and TIMP2 (all P < 0.05). (3) In comparison with the control group, the mRNA expression of VEGF and of Ang-2 of the tumor cells of the NCTD group were both significantly lower and the mRNA expression of TIMP2 was significantly higher. NCTD down-regulates the expression of the angiogenic factors, such as VEF|GF and Ang-2, and up-regulates the expression of the anti-angiogenic factors, such as TDP and TIMP2, thus inhibiting the angiogenesis in tumor, such as human gallbladder carcinoma, and further inhibiting the growth of tumor.

Cytokine responses of bovine macrophages to diverse clinical Mycobacterium avium subspecies paratuberculosis strains

BackgroundMycobacterium avium subsp. paratuberculosis (MAP), the causative agent of Johne's disease (JD) persistently infects and survives within the host macrophages. While it is established that substantial genotypic variation exists among MAP, evidence for the correlates that associate specific MAP genotypes with clinical or sub-clinical disease phenotypes is presently unknown. Thus we studied strain differences in intracellular MAP survival and host responses in a bovine monocyte derived macrophage (MDM) system.ResultsIntracellular survival studies showed that a bovine MAP isolate (B1018) and a human MAP isolate (Hu6) persisted in relatively higher numbers when compared with a sheep MAP isolate (S7565) at 24-hr, 48-hr and 96-hr post infection (PI). MDMs stimulated with B1018 up-regulated IL-10 at the transcript level and down-regulated TNFα at the protein and transcript levels compared with stimulations by the S7565 and Hu6. MDMs infected with Hu6 showed a down regulatory pattern of IL-10 and TNFα compared to stimulations by S7565. Cells stimulated with B1018 and Hu6 had low levels of matrix metalloprotease-3 (MMP3) and high levels of tissue inhibitor of metalloprotease-1 (TIMP1) at 96-hr PI relative to MDMs stimulated by S7565.ConclusionTaken together, results suggest that the bovine (B1018) and the human (Hu6) MAP isolates lead to anti-inflammatory and anti-invasive pathways in the macrophage environment whereas the sheep (S7565) MAP isolate induces a pro-inflammatory pathway. Thus the infecting strain genotype may play a role in polarizing the host immune responses and dictate the clinicopathological outcomes in this economically important disease.

Mast cell-dependent activation of pro matrix metalloprotease 2: a role for serglycin proteoglycan-dependent mast cell proteases

The formation of active matrix metalloprotease-2 (MMP-2) requires the proteolytic processing of proMMP-2, a process that can occur through the formation of a ternary complex between proMMP-2, the tissue inhibitor of metalloprotease-2 and membrane type 1-MMP. However, other activation mechanisms have been suggested, and in this study we investigated whether mast cells (MCs) may play a role in the activation of proMMP-2. Murine peritoneal cells, a mixture of macrophages, lymphocytes and MCs, were cultured ex vivo. Addition of proMMP-2 to resting peritoneal cell cultures resulted in only slow conversion of proMMP-2 into the active enzyme. However, when MC degranulation was provoked using a calcium ionophore, proMMP-2 processing was markedly enhanced. When the peritoneal cell populations were depleted in MCs, proMMP-2 processing was abrogated, but was reconstituted when purified MCs were added to the depleted cultures. ProMMP-2 processing was sensitive to serine protease inhibitors, but not to inhibitors of other classes of proteases. Furthermore, proMMP-2 processing was completely abrogated in cells lacking serglycin, a proteoglycan that has previously been shown to mediate storage of a variety of MC serine proteases. Taken together, these results suggest a novel mode of proMMP-2 activation mediated by serglycin-dependent MC serine proteases.

Piper longum inhibits VEGF and proinflammatory cytokines and tumor-induced angiogenesis in C57BL/6 mice

The antiangiogenic activity of Piper longum was studied using in vivo as well as in vitro models. In vivo , antiangiogenic activity was studied using B16F-10 melanoma cell-induced capillary formation in C57BL/6 mice. Intraperitoneal administration of the extract (10 mg/dose/animal) significantly inhibited (50.6%) the number of tumor-directed capillaries induced by injecting B16F-10 melanoma cells on the ventral side of C57BL/6 mice. The cytokine profile in the serum of these animals showed a drastically increased level of proinflammatory cytokines such as IL-1β, IL-6, TNF-α, GM-CSF and the direct endothelial cell proliferating agent, VEGF. Administration of the methanolic extract of P. longum could differentially regulate the level of these cytokines. The level of IL-2 and tissue inhibitor of metalloprotease-1 (TIMP-1) was increased significantly when the angiogenesis-induced animals were treated with the extract. The extract of P. longum at non-toxic concentrations (10 μg/ml, 5 μg/ml, 1 μg/ml) inhibited the VEGF-induced vessel sprouting in rat aortic ring assay. Moreover, P. longum was able to inhibit the VEGF-induced proliferation, cell migration and capillary-like tube formation of primary cultured human endothelial cells. Hence, the observed antiangiogenic activity of the plant P. longum is related to the regulation of these cytokines and growth factors in angiogenesis-induced animals.

Mycobacterium tuberculosis Up-Regulates Matrix Metalloproteinase-1 Secretion from Human Airway Epithelial Cells via a p38 MAPK Switch

Pulmonary cavitation is vital to the persistence and spread of Mycobacterium tuberculosis (MTb), but mechanisms underlying this lung destruction are poorly understood. Fibrillar type I collagen provides the lung's tensile strength, and only matrix metalloproteinases (MMPs) can degrade it at neutral pH. We investigated MTb-infected lung tissue and found that airway epithelial cells adjacent to tuberculosis (Tb) granulomas expressed a high level of MMP-1 (interstitial collagenase). Conditioned media from MTb-infected monocytes (CoMTb) up-regulated epithelial cell MMP-1 promoter activity, gene expression, and secretion, whereas direct MTb infection did not. CoMTb concurrently suppressed tissue inhibitor of metalloprotease-1 (TIMP-1) secretion, further promoting matrix degradation, and in Tb patients very low TIMP-1 expression was detected. MMP-1 up-regulation required synergy between TNF-alpha and G protein-coupled receptor signaling pathways. CoMTb stimulated p38 MAPK phosphorylation, and this is the point of TNF-alpha synergy with G protein-coupled receptor activation. Furthermore, p38 phosphorylation was the switch up-regulating MMP-1 activity and decreasing TIMP-1 secretion. Activated p38 localized to MMP-1-secreting airway epithelial cells in Tb patients. These data reveal a monocyte-epithelial cell network whereby MTb may drive tissue destruction, and they demonstrate that p38 phosphorylation is a key regulatory point in the generation of a matrix-degrading phenotype.

Constitutive and Accelerated Shedding of Murine Syndecan-1 Is Mediated by Cleavage of Its Core Protein at a Specific Juxtamembrane Site

Syndecan-1 is a developmentally regulated cell surface heparan sulfate proteoglycan (HSPG). It functions as a coreceptor for a variety of soluble and insoluble ligands and is implicated in several biological processes, including differentiation, cell migration, morphogenesis, and recently feeding behavior. The extracellular domain of syndecan-1 is proteolytically cleaved at a juxtamembrane site by tissue inhibitor of metalloprotease-3 (TIMP-3)-sensitive metalloproteinases in response to a variety of physiological stimulators and stress in a process known as shedding. Shedding converts syndecan-1 from a membrane-bound coreceptor into a soluble effector capable of binding the same ligands. We found that replacing syndecan-1 juxtamembrane amino acid residues A243-S-Q-S-L247 with human CD4 amino acid residues can completely block PMA-induced syndecan-1 ectodomain shedding. Furthermore, using liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS), we identified the proteolytic cleavage site of syndecan-1 as amino acids A243 and S244, generated by constitutive and PMA-induced shedding from murine NMuMG cells. Finally, we show that basal cleavage of syndecan-1 utilizes the same in vivo site as the in vitro site. Indeed, as predicted, transgenic mice expressing the syndecan-1/CD4 cDNA do not shed the syndecan-1 ectodomain in vivo. These results suggest that the same cleavage site is utilized for basal syndecan-1 ectodomain shedding both in vitro from NMuMG and CHO cells and in vivo.

Protease-Antiprotease Imbalance in Inflammatory Diseases in the Lung

We are very interested in the extensive research by Vernooy et al,1 who addressed the importance of matrix metalloproteases (MMPs) in the pathogenesis and/or the development of COPD. It is likely to be important to evaluate the activity of the proteases rather than the expression of MMPs. Protease/antiprotease imbalance has also been postulated to be important in the pathogenesis of COPD. However, the authors did not refer to the activity of the inhibitor of MMPs, tissue inhibitor of metalloprotease (TIMP).

A disintegrin and metalloprotease 21 (ADAM21) is associated with neurogenesis and axonal growth in developing and adult rodent CNS

We have reported that alpha6beta1 integrin regulates the directed migration of neuroblasts from the adult rodent subventricular zone (SVZ) through the rostral migratory stream (RMS). ADAM (a disintegrin and metalloprotease) proteins bind integrins. Here, we show that ADAM21, but not ADAM2, -3, -9, -10, -12, -15, or -17, is expressed in adult rats and mice by ependyma and SVZ cells with long basal processes, and in radial glia at early postnatal times. ADAM21-positive processes projected into the RMS, contacted blood vessels, and were present within the RMS intermingled with neuroblasts up to where neuroblasts start their radial migration and differentiation in the olfactory bulb. Tissue inhibitors of metalloproteases (TIMPs) 1, 2, and 3 are present in the ependymal layer but not in the SVZ and RMS. Thus, ADAM21 could regulate neurogenesis and guide neuroblast migration through cleavage-dependent activation of proteins and integrin binding. ADAM21 is also present in growing axonal tracts during postnatal development and in growing primary olfactory axons in adults. In the olfactory nerve layer, ADAM21 often, but not always, colocalizes with OMP, a marker of mature olfactory neurons, but is not colocalized with the immature marker betaIII-tubulin. This suggests that ADAM21 is involved in the final axonal outgrowth phase and/or synapse formation. TIMP3 is present in periglomerular neurons, where it could restrict ADAM21-mediated axonal growth to the glomeruli. ADAM21's unique disintegrin and metalloprotease sequences and its restricted expression suggest that it might be a good target for influencing neurogenesis and neuronal plasticity.

Cross-talk between farnesoid-X-receptor (FXR) and peroxisome proliferator-activated receptor gamma contributes to the antifibrotic activity of FXR ligands in rodent models of liver cirrhosis.

The nuclear receptors farnesoid X receptor (FXR) and peroxisome proliferator-activated receptor (PPAR)gamma exert counter-regulatory effects on hepatic stellate cells (HSCs) and protect against liver fibrosis development in rodents. Here, we investigated whether FXR ligands regulate PPARgamma expression in HSCs and models of liver fibrosis induced in rats by porcine serum and carbon tetrachloride administration and bile duct ligation. Our results demonstrate that HSCs trans-differentiation associated with suppression of PPARgamma mRNA expression, whereas FXR mRNA was unchanged. Exposure of cells to natural and synthetic ligands of FXR, including 6-ethyl chenodeoxycholic acid (6-ECDCA), a synthetic derivative of chenodeoxycholic acid, reversed this effect and increased PPARgamma mRNA by approximately 40-fold. Submaximally effective concentrations of FXR and PPARgamma ligands were additive in inhibiting alpha1(I) collagen mRNA accumulation induced by transforming growth factor (TGF)beta1. Administration of 6-ECDCA in rats rendered cirrhotic by porcine serum and carbon tetrachloride administration or bile duct ligation reverted down-regulation of PPARgamma mRNA expression in HSCs. Cotreatment with 6-ECDCA potentiates the antifibrotic activity of rosiglitazone, a PPARgamma ligand, in the porcine serum model as measured by morphometric analysis of liver collagen content, hydroxyproline, and liver expression of alpha1(I) collagen mRNA, alpha-smooth muscle actin, fibronectin, TGFbeta1, and tissue inhibitor of metalloprotease 1 and 2, whereas it enhanced the expression of PPARgamma and uncoupling protein 2, a PPARgamma-regulated gene, by 2-fold. In conclusion, by using an in vitro and in vivo approach, we demonstrated that FXR ligands up-regulate PPARgamma mRNA in HSCs and in rodent models of liver fibrosis. A FXR-PPARgamma cascade exerts counter-regulatory effects in HSCs activation.

Upregulated MT1-MMP/TIMP-2 axis in the TSU-Pr1-B1/B2 model of metastatic progression in transitional cell carcinoma of the bladder

Muscle invasive transitional cell carcinoma (TCC) of the bladder is associated with a high frequency of metastasis, resulting in poor prognosis for patients presenting with this disease. Models that capture and demonstrate step-wise enhancement of elements of the human metastatic cascade on a similar genetic background are useful research tools. We have utilized the transitional cell carcinoma cell line TSU-Pr1 to develop an in vivo experimental model of bladder TCC metastasis. TSU-Pr1 cells were inoculated into the left cardiac ventricle of SCID mice and the development of bone metastases was monitored using high resolution X-ray. Tumor tissue from a single bone lesion was excised and cultured in vitro to generate the TSU-Pr1-B1 subline. This cycle was repeated with the TSU-Pr1-B1 cells to generate the successive subline TSU-Pr1-B2. DNA profiling and karyotype analysis confirmed the genetic relationship of these three cell lines. In vitro, the growth rate of these cell lines was not significantly different. However, following intracardiac inoculation TSU-Pr1, TSU-Pr1-B1 and TSU-Pr1-B2 exhibited increasing metastatic potential with a concomitant decrease in time to the onset of radiologically detectable metastatic bone lesions. Significant elevations in the levels of mRNA expression of the matrix metalloproteases (MMPs) membrane type 1-MMP (MT1-MMP), MT2-MMP and MMP-9, and their inhibitor, tissue inhibitor of metalloprotease-2 (TIMP-2), across the progressively metastatic cell lines, were detected by quantitative PCR. Given the role of MT1-MMP and TIMP-2 in MMP-2 activation, and the upregulation of MMP-9, these data suggest an important role for matrix remodeling, particularly basement membrane, in this progression. The TSU-Pr1-B1/B2 model holds promise for further identification of important molecules.

Extracellular Matrix Metalloprotease Inducer–Expressing Head and Neck Squamous Cell Carcinoma Cells Promote Fibroblast-Mediated Type I Collagen Degradation In vitro

Until recently, tumor progression has been considered a multistep process defined by tumor cell mutations and the importance of the surrounding stroma poorly understood. It is now recognized that matrix-degrading enzymes that promote tumor cell invasion are elaborated by both tumor cells and fibroblasts in vivo. To determine the relative role of tumor cell-derived proteases compared with fibroblast-derived proteases, coculture experiments were done with each cell type using an in vitro model of type I collagen degradation. Head and neck squamous cell carcinoma cells in coculture with normal dermal fibroblasts showed matrix degradation, but neither cell type alone produced this effect. Manipulating the in vitro coculture environment showed that collagenolysis in this model was a result of fibroblast-derived matrix metalloproteases (MMP). To explore the possible role of extracellular matrix metalloprotease inducer (EMMPRIN) in this interaction, transfection of EMMPRIN into a cell line with low endogenous EMMPRIN expression was done and showed a significant increase in collagenolysis. Inhibition of collagenolysis with a tissue inhibitor of metalloprotease-2 (TIMP-2) and a synthetic furin inhibitor was observed but not with TIMP-1, which suggested a possible role for membrane type-1 MMP. These results suggest that fibroblast-derived MMPs but not those from tumor cells are important for in vitro collagenolysis and that this process is promoted by tumor cell-expressed EMMPRIN.

Up-regulation of TRAIL mRNA expression in peripheral blood mononuclear cells from patients with minimal-change nephrotic syndrome

Minimal-change nephrotic syndrome (MCNS) is considered to be associated with T-cell dysfunction and with the abnormal secretion of putative glomerular permeability factors; however, the nature of such factors remains elusive. To identify up-regulated genes during the nephrosis phase, we undertook serial analyses of gene expression (SAGE) in peripheral blood mononuclear cells (PBMC) from a patient with MCNS sampled during the nephrosis and remission phases. To confirm the SAGE results, we performed quantitative real-time reverse transcription-polymerase chain reaction (RT-PCR) analyses. We also measured the serum levels of the identified gene product in nephrosis and remission samples from 29 MCNS patients, 57 patients with nephrotic syndrome due to other types of glomerular diseases and 30 healthy individuals. Using more than 20,000 SAGE tags, we identified 15 functionally known genes that were up-regulated (>or=4-fold) in PBMC from the MCNS patient during the nephrosis phase. For further examination, we selected two genes encoding secretory proteins, namely tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) and tissue inhibitor of metalloprotease 1. Real-time RT-PCR analysis confirmed a higher expression of TRAIL mRNA in PBMC during nephrosis than during remission in eight MCNS patients. The expression pattern of TRAIL mRNA, however, was variable among four patients with membranous nephropathy. There was no significant increase of serum levels of a soluble form of TRAIL in MCNS patients during the nephrosis phase. These results suggest that the intracellular TRAIL mRNA expression in PBMC is up-regulated in MCNS patients during the nephrosis phase. This change may represent either an epiphenomenon or it may provide a potential explanation for the altered T-cell function in MCNS.