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S S Apte

Publications and source records attributed to S S Apte.

At least 19 recordsLinked to original sources
PubMed1999

ADAM-TS8, a novel metalloprotease of the ADAM-TS family located on mouse chromosome 9 and human chromosome 11.

A disintegrin-like and metalloprotease domain with thrombospondin type I modules (ADAM-TS) describes a novel family of zinc metalloendopeptidases. Its members have a common domain organization, which includes, typically, a pre-pro-metalloprotease domain, a disintegrin-like domain, and one or more thrombospondin-like (TS) modules. We describe here the complete primary structure of mouse ADAM-TS8, through cloning of Adamts8 cDNA. This novel member of the family contains two TS modules and is highly similar in sequence and domain organization to three other recently described gene products, ADAM-TS5, ADAM-TS6, and ADAM-TS7. Adamts8 is expressed at low levels throughout development and in adult mouse lung and heart. Through analysis of an interspecific backcross panel, we place the Adamts8 locus on mouse chromosome 9 at a consensus position of 11 cM and its human ortholog, recently reported as the METH2 gene, on human chromosome 11q25.

ADAM Proteins↗
PubMed1999

ADAM-TS5, ADAM-TS6, and ADAM-TS7, novel members of a new family of zinc metalloproteases. General features and genomic distribution of the ADAM-TS family.

We report the primary structure of three novel, putative zinc metalloproteases designated ADAM-TS5, ADAM-TS6, and ADAM-TS7. All have a similar domain organization, comprising a preproregion, a reprolysin-type catalytic domain, a disintegrin-like domain, a thrombospondin type-1 (TS) module, a cysteine-rich domain, a spacer domain without cysteine residues, and a COOH-terminal TS module. These genes are differentially regulated during mouse embryogenesis and in adult tissues, with Adamts5 highly expressed in the peri-implantation period in embryo and trophoblast. These proteins are similar to four other cognate gene products, defining a distinct family of human reprolysin-like metalloproteases, the ADAM-TS family. The other members of the family are ADAM-TS1, an inflammation-induced gene, the procollagen I/II amino-propeptide processing enzyme (PCINP, ADAM-TS2), and proteins predicted by the KIAA0366 and KIAA0688 genes (ADAM-TS3 and ADAM-TS4). Individual ADAM-TS members differ in the number of COOH-terminal TS modules, and some have unique COOH-terminal domains. The ADAM-TS genes are dispersed in human and mouse genomes.

ADAM Proteins↗
PubMed1999

Egr-1 mediates extracellular matrix-driven transcription of membrane type 1 matrix metalloproteinase in endothelium.

Matrix metalloproteinase activity is instrumental in processes of cellular invasion. The interstitial invasion of endothelial cells during angiogenesis is accompanied by up-regulation of several matrix metalloproteinases, including membrane type 1 matrix metalloproteinase (MT1-MMP). In this study, we show that endothelial cells stimulated to undergo angiogenesis by a three-dimensional extracellular matrix environment increase production of the transcription factor Egr-1. Increased binding of Egr-1 to the MT1-MMP promoter correlates with enhanced transcriptional activity, whereas mutations in the Egr-1 binding site abrogate the increased transcription of MT1-MMP in the stimulated cells. These data identify Egr-1-mediated transcription of MT1-MMP as a mechanism by which endothelial cells can initiate an invasive phenotype in response to an alteration in extracellular matrix environment, thus functionally associating MT1-MMP with a growing number of proteins known to be up-regulated by Egr-1 in response to tissue injury or mechanical stress.

Animals↗
PubMed1999

Human tissue inhibitor of metalloproteinases 3 interacts with both the N- and C-terminal domains of gelatinases A and B. Regulation by polyanions.

We compared the association constants of tissue inhibitor of metalloproteinases (TIMP)-3 with various matrix metalloproteinases with those for TIMP-1 and TIMP-2 using a continuous assay. TIMP-3 behaved more like TIMP-2 than TIMP-1, showing rapid association with gelatinases A and B. Experiments with the N-terminal domain of gelatinase A, the isolated C-terminal domain, or an inactive progelatinase A mutant showed that the hemopexin domain of gelatinase A makes an important contribution to the interaction with TIMP-3. The exchange of portions of the gelatinase A hemopexin domain with that of stromelysin revealed that residues 568-631 of gelatinase A were required for rapid association with TIMP-3. The N-terminal domain of gelatinase B alone also showed slower association with TIMP-3, again implying significant C-domain interactions. The isolation of complexes between TIMP-3 and progelatinases A and B on gelatin-agarose demonstrated that TIMP-3 binds to both proenzymes. We analyzed the effect of various polyanions on the inhibitory activity of TIMP-3 in our soluble assay. The association rate was increased by dextran sulfate, heparin, and heparan sulfate, but not by dermatan sulfate or hyaluronic acid. Because TIMP-3 is sequestered in the extracellular matrix, the presence of certain heparan sulfate proteoglycans could enhance its inhibitory capacity.

Amino Acid Sequence↗
PubMed1998

Cloning of the human tissue inhibitor of metalloproteinase-4 gene (TIMP4) and localization of the TIMP4 and Timp4 genes to human chromosome 3p25 and mouse chromosome 6, respectively.

We have isolated genomic DNA containing the human tissue inhibitor of metalloproteinases-4 gene (TIMP4) and determined the structure of the exons comprising the gene. Like other members of the TIMP family, the TIMP-4 protein is encoded by five exons. These span 6 kb of genomic DNA, so that TIMP4 is similar in size to Timp1 but considerably smaller than TIMP2 and TIMP3. The exon-intron boundaries of TIMP4 are at locations very similar to those of the other TIMP genes, demonstrating the high degree of conservation of gene structure in this family. The human and mouse TIMP-4 genes map to comparable locations in the respective genomes, localizing to human chromosome 3p25 and mouse chromosome 6.

Animals↗
PubMed1998

Accumulation of tissue inhibitor of metalloproteinases-3 in human eyes with Sorsby's fundus dystrophy or retinitis pigmentosa.

BACKGROUND/AIMS: Tissue inhibitor of metalloproteinases-3 (TIMP-3) is normally synthesised by the retinal pigment epithelium (RPE) and deposited in Bruch's membrane. Mutations in the TIMP3 gene cause Sorsby's fundus dystrophy (SFD), which is characterised by thickening of Bruch's membrane, choroidal neovascularisation, and photoreceptor degeneration. To elucidate the role of TIMP-3 in human retinal degenerative diseases, we immunolocalised TIMP-3 in eyes with SFD caused by the Ser-181-Cys TIMP3 gene mutation or retinitis pigmentosa (RP; not caused by TIMP3 mutations). METHODS: Standard light microscopic immunocytochemistry, including antigen retrieval, was used to localise TIMP-3 in paraffin sections of human eyes: two with SFD, three with different genetic forms of RP, and two normal. RESULTS: In the SFD eyes, the thickened Bruch's membrane was strongly TIMP-3 positive except where RPE cells had degenerated. Similarly, in the RP eyes, Bruch's membrane was TIMP-3 positive except where RPE cells were lost, consistent with ongoing RPE mediated turnover of TIMP-3 in this region. In areas of total photoreceptor loss, migrated RPE cells formed cuffs around blood vessels in the RP retinas. Thick, TIMP-3 positive extracellular matrix (ECM) deposits associated with the migrated RPE cells occluded some vascular lumina, correlating with the observed loss of inner retinal neurons in RP. CONCLUSIONS: TIMP-3 is a component of the increased ECM sequestered in Bruch's membrane in SFD. Further information is needed on normal TIMP-3/ECM interactions in Bruch's membrane and the effect of mutant TIMP-3 on this process. The finding of TIMP-3 accumulations in retinas with RP not caused by TIMP-3 mutations emphasises the importance of ECM remodelling in normal and diseased human eyes.

Aged↗
PubMed1998

Production of membrane-type matrix metalloproteinase-1 (MT-MMP-1) in early human placenta. A possible role in placental implantation?

The extracellular matrix proteolytic machinery is known to play a major role in trophoblast invasion, a process that shares similar features with the pathology of tumor invasion. In this study we investigated the expression of the recently described membrane-type matrix metalloproteinase-1 (MT-MMP-1; MMP-14) in early human placenta and decidual membrane to determine whether it might play a role in invasion. With in situ hybridization, the cytotrophoblasts of trophoblastic columns and the infiltrating intermediate trophoblasts in the decidual membrane were found to be the main producers of MT-MMP-1 mRNA. Gene expression was also seen in the villous double-layered trophoblastic epithelium and in the decidual cells of the decidual membrane. In endothelial and fibroblastic cells, however, the hybridization signal was either very weak or nonexistent. Immunohistochemical analysis and immunoelectron microscopy correlated well with the in situ hybridization findings. The most significant exception to this consisted of pericytes of spiral arteries, which appeared to lack MT-MMP-1 mRNA but showed intensive intracytoplasmic staining for the antigen. Our results show that MT-MMP-1 mRNA production is highly characteristic of intermediate trophoblasts, and MT-MMP-1 may have general importance in the tissue organization of early human placenta. We propose that MT-MMP-1 could be one of the key enzymes in the process of trophoblast invasion, acting alone or as a cell-surface activator of other proteinases.

Chorionic Villi↗
PubMed1997

The matrix metalloproteinase-14 (MMP-14) gene is structurally distinct from other MMP genes and is co-expressed with the TIMP-2 gene during mouse embryogenesis.

The matrix metalloproteinases (MMPs) are a family of zinc-containing matrix degrading endopeptidases. A subfamily of membrane type (MT) -MMPs has been described recently. We have determined the structure of the gene (Mmp14) encoding the first MT-MMP to be described, MT1-MMP (MMP-14), and mapped it to mouse chromosome 14. The mouse MMP-14 protein is encoded by ten exons. The novel C-terminal peptide domains of MMP-14 are encoded by a single large exon that also encodes the 3'-untranslated region. The structure of the exons encoding the catalytic domain and pro-domain of MMP-14 is distinct from previously described MMP genes, whereas the exons encoding the hemopexin-like domains are similar to those of most other MMP genes. Mmp14 and the gene for tissue inhibitor of metalloproteinases-2 (Timp2) show a temporally and spatially co-regulated expression during mouse development. They are co-expressed during vascular and urogenital development and during the development of osteocartilaginous and musculotendinous structures. The stringent co-expression of these two genes suggests common regulatory pathways that may have important functional implications for the activation of pro-gelatinase A in health and disease.

Animals↗
PubMed1997

Genes of the membrane-type matrix metalloproteinase (MT-MMP) gene family, MMP14, MMP15, and MMP16, localize to human chromosomes 14, 16, and 8, respectively.

The membrane-type matrix metalloproteinases (MT-MMPs) constitute a newly discovered family of four enzymes within the matrix metalloproteinase (MMP) superfamily. We have mapped the genes for MT1-MMP (MMP14), MT2-MMP (MMP15), and MT3-MMP (MMP16) using in situ hybridization to human metaphase chromosomes. In contrast to the genes for many MMPs that are clustered on chromosome 11, the genes MMP14, MMP15, and MMP16 all map to distinct chromosomes. MMP14 maps to human chromosome 14, MMP15 to human chromosome 16, and MMP16 to human chromosome 8.

Cells, Cultured↗
PubMed1997

Murine tissue inhibitor of metalloproteinases-4 (Timp-4): cDNA isolation and expression in adult mouse tissues.

We have isolated cDNA clones corresponding to a new member of the murine tissue inhibitor of metalloproteinase (TIMP) family, designated Timp-4. The nucleotide sequence predicts a protein of 22,609 Da that contains the characteristic 12 cysteine TIMP signature. TIMP-4 is more closely related to TIMP-2 and TIMP-3 than to TIMP-1 (48%, 45% and 38% identity, respectively). Analysis of Timp-4 mRNA expression in adult mouse tissues indicated a 1.2 kb transcript in brain, heart, ovary and skeletal muscle. This pattern of expression distinguishes Timp-4 from other Timps, suggesting that the TIMP-4 protein may be an important tissue-specific regulator of extracellular matrix remodelling.

Amino Acid Sequence↗
PubMed1997

Tissue inhibitor of metalloproteinases-3 is a component of Bruch's membrane of the eye.

Mutations in tissue inhibitor of metalloproteinases (TIMP)-3 are found in some patients with Sorsby's fundus dystrophy, a retinal degeneration characterized by abnormal deposits in Bruch's membrane and choroidal neovascularization. The purpose of this study was to localize TIMP-3 in the retina/choroid of normal human and animal eyes. Immunolabeling was performed on unfixed and fixed sections of human eyes aged 24 to 85 years and unfixed sections of baboon, chicken, cow, pig, and rat eyes using a monoclonal antibody against a human TIMP-3 synthetic peptide. The antibody produced strong immunolabeling of Bruch's membrane and drusen and weak labeling of retina blood vessels in unfixed human and baboon eyes. Unfixed chicken, cow, pig, and rat tissues showed no reactivity. After antigen retrieval, all fixed human eyes showed specific labeling of Bruch's membrane and drusen, which was strongest in eyes from elderly donors. The results indicate that TIMP-3 is an extracellular matrix component of Bruch's membrane. Thus, abnormal local function of TIMP-3 may lead to the characteristic Bruch's membrane deposits and choroidal neovascularization found in Sorsby's fundus dystrophy. Specific labeling of drusen raises the possibility that altered TIMP-3-mediated matrix remodeling may contribute to age-related degenerative changes in Bruch's membrane.

Adult↗
PubMed1997

Inhibition of angiogenesis by tissue inhibitor of metalloproteinase-3.

PURPOSE: It has been established that Sorsby's fundus dystrophy, a dominantly inherited form of blindness, is caused by mutations in the tissue inhibitor of metalloproteinase-3 (TIMP-3) gene. Because choroidal neovascularization is a prominent feature of Sorsby's fundus dystrophy, the authors have examined whether TIMP-3 protein plays a role in the regulation of angiogenesis. METHODS: Chemotaxis of endothelial cells toward vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) was examined using a modified Boyden chamber assay. Endothelial cells placed in the upper chamber were allowed to migrate through a polycarbonate membrane with 8 microns pores toward VEGF or bFGF present in the lower chamber. Next, the ability of TIMP-3 to inhibit chemotaxis was studied by incubating the cells with varying amounts of TIMP-3 during the assay. Finally, an in vitro angiogenesis assay was performed on collagen gels. Endothelial cells were seeded onto three-dimensional collagen gels. Treatment with bFGF and VEGF induced invasion of the gel and the formation of tube-like structures. TIMPs (1, 2, and 3) were added to the cultures to determine their effect on invasion. An in vivo chorioallantoic membrane (CAM) assay was performed using methylcellulose discs containing bFGF with or without TIMP-3. Induction of new blood vessels was observed with a stereomicroscope. RESULTS: TIMP-3 inhibits chemotaxis of vascular endothelial cells toward VEGF and bFGF, inhibits collagen gel invasion and capillary morphogenesis in vitro, and inhibits bFGF-induced angiogenesis in the CAM assay in vivo. CONCLUSIONS: TIMP-3 has the potential to inhibit angiogenesis. These results allow us to speculate on a possible mechanism by which mutant TIMP-3 protein might contribute to the Sorsby fundus dystrophy phenotype.

Allantois↗
PubMed1996

Oncostatin M differentially regulates tissue inhibitors of metalloproteinases TIMP-1 and TIMP-3 gene expression in human synovial lining cells.

Tissue inhibitor of metalloproteinases (TIMP) 1, 2 and 3 are related proteins that can form complexes with all known matrix metalloproteinases (MMPs). They inhibit the action of MMPs on extracellular matrix components. The balance of MMPs and TIMPs is important for tissue remodeling and its disturbance is believed to play a crucial role in pathophysiological processes such as tumor metastasis, destruction of cartilage and fibrosis. Cytokines and growth factors were found to regulate TIMPs and MMPs in a complex manner. In order to better understand the role of TIMPs in inflammatory joint diseases we have studied in vitro the regulation of TIMP-1 and TIMP-3 by inflammatory cytokines in cultured human synovial lining cells. We found that transforming growth factor beta 1 as well as interleukin-1 beta induce gene expression of both TIMP-1 and TIMP-3. In contrast, oncostatin M, an interleukin-6-type cytokine produced by activated T-lymphocytes and monocytes, had a differential effect on TIMP mRNA levels. After oncostatin M treatment, TIMP-1 expression was up-regulated but basal, as well as interleukin-1 beta-induced, TIMP-3 expression was inhibited. Interleukin-6 itself had no effect on synovial lining cells but a complex of interleukin-6 and the soluble interleukin-6 receptor induced activation of signal transducer and activator of transcription (STAT) factors in these cells and regulated TIMP-1 and TIMP-3 expression in a similar fashion as oncostatin M. Since TIMP-3 is matrix-associated whereas TIMP-1 is found in many body fluids, the role of oncostatin M during inflammatory processes might be to promote ECM degradation in the local environment but to prevent it systemically.

Blotting, Northern↗
PubMed1996

A review of tissue inhibitor of metalloproteinases-3 (TIMP-3) and experimental analysis of its effect on primary tumor growth.

The family of tissue inhibitors of metalloproteinases (TIMPs) presently numbers four distinct gene products that are specific inhibitors of the matrix metalloproteinases (MMPs). The local balance between MMPs and TIMPs is believed to play a major role in extracellular matrix (ECM) remodeling during development and in diseases such as cancer and arthritis. Unlike the other TIMPs, which are soluble. TIMP-3 is unique in being a component of ECM. Mutations in the human TIMP-3 gene cause a dominantly inherited, adult-onset blindness (Sorsby's fundus dystrophy or SFD). In this article, we summarize what is currently known about TIMP-3, discuss possible mechanisms leading up to SFD, and investigate the effect of TIMP-3 on tumor growth. Breast carcinoma and malignant melanoma cell lines were transfected with TIMP-3 expression plasmids and injected subcutaneously into nude mice. Growth curves of the resulting tumors over a period of 6 to 8 weeks demonstrated that increased expression of TIMP-3 resulted in a statistically significant suppression of tumor growth. Deposition of TIMP-3 in the surrounding ECM by tumor cells may inhibit tumor growth by preventing local expansion of tumor, retarding the release of growth factors sequestered in ECM, or inhibiting angiogenesis. TIMP-3 over-expression had no effect on the growth of the two tumor cell lines in vitro. Because recombinant TIMP-3 inhibits endothelial cell migration and tube formation in response to angiogenic factors, we believe that the effect of TIMP-3 on tumor growth seen in this study may be a consequence of its angiostatic action.

Animals↗
PubMed1995

Structure of the human TIMP-3 gene and its cell cycle-regulated promoter.

The gene encoding tissue inhibitor of metalloproteinases-3 (TIMP-3) is regulated during development, mitogenic stimulation and normal cell cycle progression. The TIMP-3 gene is structurally altered or deregulated in certain diseases of the eye and in tumour cells. A detailed knowledge of the TIMP-3 gene and its regulatory elements is therefore of paramount importance to understand its role in development, cell cycle progression and disease. In this study, we present the complete structure of the human TIMP-3 gene. We show that TIMP-3 is a TATA-less gene, which initiates transcription at one major site, is composed of five exons and four introns spanning a region of approximately 30 kb, and gives rise to three distinct mRNAs, presumably due to the usage of alternative polyadenylation signals. Using somatic cell hybrids the TIMP-3 locus was mapped to chromosomal location 22q13.1 We also show that the TIMP-3 5' flanking region is sufficient to confer both high basal level expression in growing cells and cell cycle regulation in serum-stimulated cells. While the first 112 bases of the promoter, which harbour multiple Sp1 sites, were found to suffice for high basal level activity, the adjacent region spanning positions -463 and -112 was found to be a major determinant of serum inducibility. These results provide an important basis for further investigations addressing the role of TIMP-3 in physiological processes and pathological conditions.

3T3 Cells↗